WO2014159792A1

WO2014159792A1 - Curable silicone compositions, electrically conductive silicone adhesives, methods of making and using same, and electrical devices containing same

Info

Publication number: WO2014159792A1
Application number: PCT/US2014/025151
Authority: WO
Inventors: John Albaugh; Brian CHISLEA; Adriana ZAMBOVA
Original assignee: Dow Corning Corporation
Priority date: 2013-03-14
Filing date: 2014-03-13
Publication date: 2014-10-02

Abstract

A curable silicone composition containing a curable organosiloxane composition, silver, and at least one electrically conductive metal other than silver, the curable silicone composition being characterizable by a total concentration of silver of less than 45 weight percent and lacking gold and copper metals while the composition remains curable to an electrically conductive silicone adhesive having a volume resistivity of less than 0.003 Ohm-centimeter without increasing the concentration of silver in the curable silicone composition to 45 weight percent or higher and without increasing total concentration of electrically conductive metal in the curable silicone composition to 80 weight percent or higher, the electrically conductive silicone adhesive, an electrical device comprising the electrically conductive silicone adhesive, and a method of manufacturing the electrical device; wherein the total concentration of all solids in the curable silicone composition is at least 60 weight percent.

Description

Curable Silicone Compositions, Electrically Conductive Silicone Adhesives, Methods of Making and Using Same, and Electrical Devices Containing Same

[001] Inventions described herein include curable silicone compositions, electrically conductive silicone adhesives, methods of making and using the compositions and adhesives, and electrical devices containing the compositions and adhesives.

[002] One approach to electrically interconnecting components of an electrical device is to use an electrically conductive adhesive (ECA). The ECA binds the components together and facilitates transfer of electric current between them via the ECA during operation of the electrical device. A wide variety of electrical components could employ ECAs.

[003] An ECA generally comprises electrically conductive metal particles dispersed in a non-conductive binder matrix at a concentration above their percolation threshold. Percolation threshold is the minimum concentration of the metal particles in the ECA that is necessary for conduction of electric current through the ECA. Just below the percolation threshold, a distinct cutoff of electric current is reached. The cutoff is at a concentration of metal particles that no longer form a continuous path for the current through the binder matrix.

[004] In addition, the ECA should have a volume resistivity compatible with its application. Volume resistivity (p) quantifies how strongly a material opposes the flow of electric current therethrough.

[005] To achieve acceptable electrical performance, the electrically conductive metal particles in most ECAs are highly electrically conductive particles, especially finely divided solids of silver or copper. Gold, and sometimes the less conductive aluminum, may be useful in some applications. Particles of other metals have much poorer electrical conductivity, as the other metals have more than two times the volume resistivity and less than half the electrical conductivity of aluminum. For example, the volume resistivity of nickel is more than 2.5 times higher than that of aluminum and the volume resistivity of tin is four times higher than that of aluminum. Even aluminum is disfavored for performance reasons in most applications.

[006] Silver-based curable silicone precursor compositions typically have a minimum of 70 weight percent (wt%) of silver for satisfactory electrical performance. Reducing the concentration of silver, which is expensive, below that minimum has led in the past to an unsatisfactory gain in volume resistivity.

[007] Artisans have made different curable precursor compositions and ECAs. Examples of curable precursor compositions and ECAs are mentioned in US 5,075,038 to R. L. Cole et al; US 5,227,093 to R. L. Cole et al.; JP 2004-027134 A to S. Miyazaki; US 8,044,330 B2 to A. Inaba; and WO 2011/101788 A1 to Kleine Jager, et al.

[008] We (the present inventors) found problems with prior art curable precursor compositions and resulting ECAs. For instance, the prior art does not teach how to achieve a curable precursor composition wherein total concentration of silver in the composition is below 45 wt% and while the volume resistivity of the resulting ECA could be maintained below 0.003 Ohm-centimeter.

[009] Also, we found that curable precursor compositions with reduced concentrations of silver particles may have too low viscosity and exhibit too much slump, bleeding, dripping, and/or filler settling during screen printing thereof.

[010] Alternatively or additionally, we found that some prior art ECAs with high silver particle concentrations have poor flexibility (i.e., are too stiff or hard), poor adhesion to a substrate such as a silicate glass (i.e., adhere weakly), or both. Flexible, adhering ECAs are beneficial in applications desiring low stress interconnections and enhanced durability of electronic devices that are exposed to wide temperature variations. We realized it would be desirable to develop a flexible, low silver concentration curable precursor formulation with good adhesion that meets the needs of manufacturing companies while retaining the ECA electrical properties needed by device users.

[011] Our efforts to solve the foregoing concentration and/or flexibility problems led us to an improved curable silicone compositions and silicone ECAs and one or more technical solutions of the foregoing problems that we believe are not disclosed, taught or suggested by the aforementioned art. We believe that attempting to solve the foregoing technical problems with only knowledge of the prior art as a whole would not result in the present invention without an inventive or nonobvious step.

BRIEF SUMMARY OF THE INVENTION

[012] The present invention includes curable silicone compositions, electrically conductive silicone adhesives, methods of making and using the same, and electrical devices containing the compositions and adhesives. Embodiments include:

[013] A curable silicone composition containing a curable organosiloxane composition, silver, and at least one filler other than silver, the curable silicone composition being characterizable by a total concentration of silver of less than 45 wt% and lacking gold and copper metals while the composition remains curable to an electrically conductive silicone adhesive having a volume resistivity of less than 0.003 Ohm-centimeter (Ω-cm) measured according to Volume Resistivity Test Method without increasing the total concentration of silver in the curable silicone composition to 45 wt% or higher and without increasing total concentration of electrically conductive metal in the curable silicone composition to 80 wt% or higher; wherein the total concentration of all solids in the curable silicone composition is at least 60 wt%.

[014] An electrically conductive silicone adhesive (ECSA) composition that is a product of curing the curable silicone composition and is characterizable by a volume resistivity of less than 0.0030 Ω-cm measured according to Volume Resistivity Test Method.

[015] An electrical device comprising first and second electrical components and the electrically conductive silicone adhesive.

[016] A method of manufacturing the electrical device.

[017] The invention may be used in electrical components, end-user devices, and methods of their manufacture.

DETAILED DESCRPTION OF THE INVENTION

[018] The Summary and Abstract are incorporated here by reference. The invention provides the curable precursor composition, the electrically conductive silicone adhesive (ECSA), the electrical device, and the method of manufacturing the electrical device.

[019] "May" confers a choice, not an imperative. Optionally" means is absent, alternatively is present. "Contact" comprises effective touching, e.g., as for facilitating reaction. The contact may be direct touching. Any reference herein to a Group or Groups of elements or the Periodic Table of the Elements means those of the 201 1 edition of the Periodic Table of the Elements promulgated by lUPAC (International Union of Pure and Applied Chemistry). Unless indicated otherwise by specific statement or context (e.g., salt or chelate), any reference to a metal, metal alloy, or metal blend herein refers to the metallic (non-ionic, formal oxidation state 0) form of the relevant element. All "wt%" (weight percent) are, unless otherwise noted, based on total weight of the ingredients used. Ingredients of each composition, mixture, or other material add up to 100 wt%. Any Markush group comprising a genus and subgenus therein includes the subgenus in the genus, e.g., in Markush group "R is hydrocarbyl or alkenyl," R may be alkenyl, alternatively R may be hydrocarbyl, which includes, among other subgenuses, alkenyl. The "curable silicone composition" may be referred to herein as "curable silicone" and the "curable organosiloxane composition" as "curable organosiloxane.

[020] As used herein, volume resistivity (p) and electrical conductivity ( ) refer to bulk volume resistivity and bulk electrical conductivity. If a volume resistivity value and electrical conductivity value inadvertently conflict, the volume resistivity value controls. The volume resistivity is > 0 Ω-cm. Unless indicated otherwise herein, all volume resistivity values are measured according to Volume Resistivity Test Method, described later. [021] The "electrically conductive metal" means an element of any one of Groups 1 to 13 of the Periodic Table of the Elements plus tin, and lead from Group 14, antimony from Group 15, bismuth from Group 16, and lanthanides and actinides, or a metal alloy of any two or more such elements. The element or metal alloy may have a volume resistivity (p) at 20° C less than 0.0001 Ω-cm and an electrical conductivity ( ) at 20° C greater than 1 x10⁶ S/m. Examples of such elements are silver, copper, gold, aluminum, calcium, molybdenum, zinc, bismuth, indium, lithium, tungsten, nickel, iron, palladium, platinum, tin, lead, titanium, mercury, and blends thereof. Examples of such metal alloys are brass (a metal alloy of copper and zinc), bronze (a metal alloy of copper and tin), 67Cu33Zn, carbon steel, grain oriented electrical steel, MANGANIN (trademark name for a metal alloy of formula Cu86^Mnl2^Ni2 by Isabellenhutte Heusler GmbH & Co. KG, Dillenburg, Germany), constantin (a metal alloy of 55% copper and 45% nickel), nichrome, and blends thereof. The total concentration of electrically conductive metal in the curable silicone is less than (<) 85 wt%, alternatively < 82 wt%, alternatively < 81 wt%, all based on weight of the curable silicone. The total concentration of electrically conductive metal in the curable silicone may be > 70 wt%, alternatively > 75 wt%, alternatively > 76 wt%, alternatively > 77 wt%, alternatively > 78 wt%, all based on weight of the curable silicone.

[022] The "highly electrically conductive metal" generally means, in order of increasing volume resistivity and decreasing electrical conductivity, silver, copper, gold, aluminum, or a blend or metal alloy of any two or more such elements. The respective elements Ag, Cu,

Au, and Al, blend and metal alloy are characterizable by volume resistivity (i.e., p < 3 x 10^" 6 Ω-cm) and electrical conductivity (K > 30 x 10^ Siemens per meter (S/m)). The highly electrically conductive metal may be Ag; alternatively a blend or alloy of Ag and Al.

[023] The curable silicone contains the curable organosiloxane, silver, and at least one electrically conductive metal other than silver. E.g., the curable silicone may comprise a blend of the following ingredients: a hydrocarbon vehicle; a curable organosiloxane; and electrically conductive filler consisting essentially of a combination of silver particles and an enhancing filler lacking silver; wherein the total concentration of all the ingredients is 100.0 wt% of the curable silicone. The curable silicone has a total concentration of silver of 20 to 45 wt% and lacks gold and copper metal, alternatively lacks gold, copper, and aluminum metal. The enhancing filler increases the efficiency of the curable silicone, or the ECSA prepared by curing the curable silicone, by increasing the electrical conductivity ( ) and/or decreasing the volume resistivity (p) of the ECSA. The increase in efficiency may be expressed as an increase in K and/or decrease in p per unit total concentration of silver in the curable silicone, or per unit total concentration of silver in the ECSA.

[024] The curable silicone may comprise a blend of the following ingredients: A hydrocarbon vehicle at a concentration of from 7 to 20 wt% based on weight of the curable silicone, wherein the hydrocarbon vehicle is characterizable by a boiling point from 100 to 360 degrees Celsius (° C); a curable organosiloxane at a concentration of from 5 to 40 wt% based on weight of the curable silicone; and electrically conductive filler consisting essentially of a combination of a silver filler and an enhancing filler lacking silver, copper, gold, and aluminum; wherein the silver filler is silver particles or a combination of silver particles and silver-coated core particles, wherein the silver particles are at a concentration of from 5 to 43 wt%, the silver-coated core particles when present are at a concentration of from > 0 to 48 wt%, and the total concentration of silver is from 19.5 to 43 wt%, all based on weight of the curable silicone; and wherein the enhancing filler is metal particles of tin, molybdenum, zinc, bismuth, indium, lithium, tungsten, nickel, iron, palladium, platinum, or a metal alloy or combination of any two or more of the foregoing metals; carbon nanotubes; electrically non-conductive filler particles; or a combination of any two or more of the metal particles, carbon nanotubes, and electrically non-conductive filler particles; wherein the metal particles, when present, are at a maximum concentration of 70 wt% (e.g., maximum of 69 wt%), the carbon nanotubes, when present, are at a maximum concentration of 5.0 wt%, the electrically non-conductive filler particles, when present, are at a maximum concentration of 50 wt% (e.g., maximum 40 wt%), and the enhancing filler is at a total concentration of from 30 to 70 wt% (e.g., maximum of 69 wt%), all based on weight of the curable silicone.

[025] The curable silicone may be characterizable by (i.e., may be curable to an ECSA having) a volume resistivity less than 0.0030 Ω-cm, alternatively < 0.0020 Ω-cm, alternatively < 0.0010 Ω-cm, alternatively < 0.00090 Ω-cm, alternatively < 0.00080 Ω-cm, alternatively < 0.00060 Ω-cm.

[026] The hydrocarbon vehicle is a liquid collection of molecules wherein each molecule consists of carbon and hydrogen atoms, including one or more than one isotopic forms of carbon and hydrogen atoms, respectively. Each molecule has carbon-carbon bonds wherein each carbon-carbon bond independently is a single, double, triple, or aromatic bond. Each molecule independently may be a saturated hydrocarbon, unsaturated hydrocarbon, aromatic hydrocarbon, or a combination of any two or three thereof. Each molecule independently may be acyclic or cyclic, or a combination of acyclic and cyclic portions. Each acyclic molecule or portion independently may be branched or unbranched. Each cyclic molecule or portion independently may be aromatic or non-aromatic. Additionally, each cyclic molecule or portion independently may be monocyclic or polycyclic, including bicyclic or tricyclic. Each polycyclic molecule or portion may be simple (separate rings that do not share atoms) or complex (having at least two rings that share at least one atom). Examples of complex polycyclic molecules are bridged, spirocyclic, and fused polycyclic. Each ring of the polycyclic molecule independently may be aromatic or non-aromatic. The hydrocarbon vehicle may be from any one or more of the following classes: alkane, alkene, alkyne, cycloalkane, cycloalkene, cycloalkyne, and aromatic hydrocarbons. The hydrocarbon vehicle may be a mixture of any two or more hydrocarbons of the same or different classes. The mixture of hydrocarbons of the same class may be a mixture of alkanes such as a mixture of unbranched alkanes (normal- alkanes) or a mixture of branched alkanes (e.g., an isoalkanes mixture, neo-alkanes mixture, or tertiary-alkanes mixture). For example, the isoalkanes mixture may comprise at least two of (Cg-C-^isoalkanes, at least two of (C-^-C-^isoalkanes or at least two of (C-| 6-C22)^isoalkanes- ^Tne mixture of hydrocarbons from different classes may be a mixture of alkanes and aromatic hydrocarbons or a mixture of alkanes and alkenes.

[027] The hydrocarbon vehicle is also characterizable by a boiling point of at least 100° C, alternatively from 100° to 360° C. The particular boiling point of the hydrocarbon vehicle is not critical so long as it is above 100° C and yet not so high that the hydrocarbon vehicle could not be substantially removed during curing of the curable silicone and/or thereafter. "Substantially removed" means removal of at least 50 volume percent (vol%), alternatively at least 75 vol%, alternatively at least 90 vol%, alternatively at least 98 vol%, alternatively at least 99 vol% removed, based on starting volume of the hydrocarbon vehicle and an amount such that the ECSA has < 5 wt%, alternatively < 4 wt%, alternatively < 3 wt%, alternatively < 2 wt%, alternatively < 1 wt% of hydrocarbon vehicle after curing has been stopped or completed. The amount of hydrocarbon vehicle remaining in the ECSA after curing may be equal to the weight of the hydrocarbon vehicle used in the curable silicone minus the weight lost during curing. The weight lost during curing may equal weight of the curable silicone before curing minus weight of the ECSA. Alternatively, thermal gravimetric analysis (TGA) may be employed to measure weight change upon heating and pyrolysis gas chromatograph-mass spectrometry may be employed to quantitatively analyze (identify and quantify) materials that have left the curable silicone or ECSA prepared therefrom during curing of the former. The hydrocarbon vehicle can be removed without degrading the ECSA to a degree of decomposition whereat the ECSA would not be able to meet its electrical, adhesive, or both limitations described herein.

[028] Additionally, an embodiment of the hydrocarbon vehicle with a particular boiling point or boiling point range may be used to accommodate beneficial curing conditions for curing the curable silicone. For example, the boiling point or boiling point range temperature range may beneficially facilitate shrinkage of volume of material during curing such that the volume of the curable silicone immediately prior to curing is higher than the volume of the resulting ECSA after curing. The shrinkage may advantageously be at a relatively slow and steady rate such that packing of the electrically conductive filler in the curable silicone is improved, resulting in lower volume resistivity and higher electrical conductivity of the ECSA than would be obtained with a comparative ECSA having a hydrocarbon vehicle having a boiling point less than 100° C, especially less than 80° C, alternatively < 60° C, alternatively < 50° C. The rate of shrinkage may be adjusted to improve packing of the electrically conductive filler in the ECSA.

[029] For most applications, a maximum boiling point (i.e., an end boiling point) of 360° C is sufficient for the hydrocarbon vehicle. When the hydrocarbon vehicle is a mixture of different hydrocarbon molecules, the hydrocarbon vehicle may be characterizable by an initial boiling point of lowest boiling molecules and an end boiling point of highest boiling molecules. For example, the hydrocarbon vehicle may have an initial boiling point greater than 150° C and an end boiling less than 300° C; alternatively an initial boiling point of greater than 210° C and an end boiling point of less than 270° C; alternatively an initial boiling point of > 160° C and an end boiling point < 205° C; alternatively an initial boiling point of > 210° C and an end boiling point < 270° C; alternatively an initial boiling point of > 270° C and an end boiling point < 355° C.

[030] The hydrocarbon vehicle may be present in the curable silicone at a concentration of from 6.5 to 20 wt%, alternatively from 6.9 to 20 wt%, alternatively from 7.0 to 15 wt%, alternatively from 7.0 to 14 wt%, alternatively from 7.0 to 1 1 wt%, all based on total weight of the curable silicone. A concentration of hydrocarbon vehicle below 6 wt% may result in volume resistivity of the resulting ECSA being > 0.01 Ω-cm, alternatively > 0.04 Ω-cm, alternatively > 0.5 Ω-cm.

[031] The "electrically conductive filler consisting essentially of a combination of a silver filler and an enhancing filler lacking silver, copper, gold, and aluminum" means the curable silicone and ECSA has less than 0.2 wt%, alternatively < 0.1 wt%, alternatively < 0.10 wt%, alternatively < 0.05 wt%, alternatively < 0.01 wt% of electrically conductive filler other than silver particles; silver-coated core particles; metal particles of tin, molybdenum, zinc, bismuth, indium, lithium, tungsten, nickel, iron, palladium, or platinum; metal alloys of any two or more of the foregoing metals; metal blends of any two or more of the foregoing metals and metal alloys; and non-diamond allotropes of carbon (e.g., carbon nanotubes). Examples of the electrically conductive filler are silver particles; silver-coated core particles; metal particles of tin, molybdenum, zinc, bismuth, indium, lithium, tungsten, nickel, iron, palladium, or platinum ; non-diamond allotropes of carbon (e.g., carbon nanotubes); metal alloys of any two or more of the foregoing metals; metal blends of any two or more of the foregoing metals and metal alloys; non-metal blends of any two or more of the non- diamond allotropes of carbon; metal and non-metal blends of any one or more of the foregoing metals and any one or more the foregoing non-diamond allotropes of carbon, and combinations thereof. The enhancing filler may be metal particles, wherein the metal particles are tin, alternatively molybdenum, alternatively zinc, alternatively bismuth, alternatively indium, alternatively lithium, alternatively tungsten, alternatively nickel, alternatively iron, alternatively palladium, alternatively platinum, alternatively a metal alloy of any two or more of the foregoing metals, alternatively a metal blend of any two or more of the foregoing metals. The electrically conductive filler, e.g., electrically conductive metal particles, may be unsintered. The non-diamond allotropes of carbon include carbon nanotubes and amorphous, fibrillar, glassy (vitreous), and graphitic polymorphs of carbon, and do not include (exclude) the diamond polymorph of carbon. The electrically conductive filler may consist essentially of a combination of a silver filler and an enhancing filler lacking silver, copper, gold, and aluminum. This means the curable silicone and ECSA has less than 0.2 wt%, alternatively < 0.1 wt%, alternatively < 0.10 wt%, alternatively < 0.05 wt%, alternatively < 0.01 wt% of electrically conductive filler other than the silver filler and enhancing filler. The curable silicone and ECSA may lack or be free of (i.e., may contain 0.00 wt% of) electrically conductive filler other than the combination. The electrically conductive filler may have an aspect ratio ranging from 1 :1 (approximately spherical) to 3,000:1 .

[032] The "silver particles" mean a finely divided solid form of the element having atomic number 47 (Ag), wherein the silver particles overall have at least 90 atomic percent (at%) Ag, alternatively > 95 at% Ag, alternatively > 98 at%, alternatively > 99.99 at% Ag. The concentration of the silver particles in the curable silicone may be from 5 to 43 wt% (e.g., an embodiment of aspect 1 described later), alternatively from 7 to 42 wt%, alternatively from 9 to 41 wt%, alternatively from 10 to 40 wt, all based on weight of the curable silicone. When the curable silicone lacks silver-coated core particles, the total concentration of silver particles in the curable silicone may be from 19.5 to 43 wt% (e.g., an embodiment of aspect 1 described later), alternatively from 19.9 to 41 wt%, alternatively from 20.0 to 40 wt%, alternatively from 20.0 to 29 wt%, alternatively from 19.5 to 25 wt%, alternatively from 19.8 to 25 wt%, alternatively from 20.0 to 24.0 wt%, all based on weight of the curable silicone.

[033] The "silver-coated core particles" mean a finely divided core-shell composite wherein the core is a solid or liquid form of an inner support material that is not silver, copper, or gold and the shell is a coating or film of the element having atomic number 47 (Ag), wherein the shell covers the inner support material. The inner support material may be a liquid having a boiling point > 300° C (e.g., mercury), alternatively a solid. In each silver-coated core particle, the inner support material may be a single particle, alternatively a cluster or agglomerate of a plurality of particles. The inner support material may be electrically conductive or electrically non-conductive (insulating). The electrically non- conductive inner support material may be silica glass, diamond polymorph of carbon, silica, organic polymer, organosiloxane polymer, or a ceramic. Therefore, the inner support material may be silica glass; carbon; a ceramic; aluminum; iron; lithium; molybdenum ; nickel; organic polymer; palladium; platinum; silica; tin; tungsten; zinc; or a metal alloy of any two or more of aluminum; iron, lithium, molybdenum, nickel, palladium, platinum, tin, tungsten, and zinc; or a physical blend of any two or more of silica glass; carbon; a ceramic; aluminum; iron; lithium; molybdenum; nickel; organic polymer; palladium; platinum; silica; tin; tungsten; zinc; and the metal alloy. The silica glass filler particles may be solid or hollow. The electrically conductive core support material in the Ag-coated core particles may be any non-silver electrically conductive particles such as solid metal particles other than Ag particles, solid metal alloy particles lacking silver, particles of non- diamond allotropes of carbon, or a mixture thereof. The inner support material may have a de minimis concentration of Ag, Au, and/or Cu; alternatively a de minimis concentration of Ag, Au, Cu, and Al. The de minimis concentration may be, as total for the sum of concentrations of Ag, Au and Cu; alternatively as total for the sum of concentrations of Ag, Au, Cu and Al, < 5 wt%, alternatively < 2 wt%, alternatively < 1 wt%. alternatively < 0.5 wt%, alternatively < 0.1 wt%, alternatively 0.0 wt%. The inner support material may lack Ag, Au, and Cu; alternatively the inner support material may lack Ag, Au, Cu, and Al. The concentration of silver in the Ag-coated core particles may be from 2 to 59 wt% (e.g., an embodiment of aspect 1 described later), alternatively from 2 to 58 wt%, alternatively from 10 to 45 wt%, alternatively from 12 to 43 wt%, alternatively from 28 to 42 wt%, all based on weight of the Ag-coated core particles. Examples of Ag-coated core particles are silver- coated nickel particles, wherein the core or inner support material is nickel. Examples of silver-coated nickel particles are Ag-coated nickel particles having 15 wt% Ag (Ag/Ni-15), 30 wt% Ag (Ag/Ni-30), or 40 wt% Ag (Ag/Ni-40), based on weight of the Ag-coated nickel particles. The concentration of the Ag-coated core particles in the curable silicone may be from 0 to 48 wt% (e.g., an embodiment of aspect 1 described later), alternatively 0 wt% (i.e., the curable silicone lacks Ag-coated core particles); alternatively from > 0 to 45 wt%, alternatively from 5 to 45 wt%, alternatively from 10 to 42 wt%, alternatively from 17 to 41 wt%, all based on weight of the curable silicone.

[034] If there is any conflict herein between the amount of silver calculated from the quantities of the silver particles and silver-coated particles (accounting for the concentration of silver in the latter) and the total concentration of silver in the curable silicone, the total concentration of silver in the curable silicone controls such that the quantities of silver particles and silver-coated particles may be adjusted, if necessary, so as to satisfy the total concentration of silver in the curable silicone. The total concentration of silver in the curable silicone may be from 19.5 to 43 wt% (e.g., an embodiment of aspect 1 described later), alternatively from 19.9 to 41 wt%, alternatively from 20.0 to 40 wt%, alternatively from 20.0 to 29 wt%, alternatively from 19.5 to 25 wt%, alternatively from 19.8 to 25 wt%, alternatively from 20.0 to 24.0 wt%, all based on weight of the curable silicone. Total concentration of silver in the curable silicone below 19 wt%, alternatively total concentration of hydrocarbon vehicle below 6 wt% and total concentration of silver below 19 wt% in the curable silicone, may result in volume resistivity of the resulting ECSA being > 0.01 Ω-cm, alternatively > 0.04 Ω-cm, alternatively > 0.5 Ω-cm. The curable silicone may lack silver from any source other than the silver particles, and the Ag-coated core particles when present. Advantageously, the concentration of silver in the curable silicone may be beneficially limited to the range of from 19.5 to 43 wt% to improve rheology, enhance durability (flexibility) of the resulting ECSA and electrical device, and/or reduce costs without losing the beneficial electrical conductivity and volume resistivity properties of the resulting ECSA.

[035] The silver particles may be characterizable by an electrical conductivity (K) of > 1 x10⁶ S/m, alternatively K≥ 1 .0x10⁷ S/m, alternatively K≥ 5.0x10⁷ S/m, alternatively K≥ 6.0x10⁷ S/m. The Ag-coated particles (e.g., Ag/Ni-40 particles) may be characterizable by an electrical conductivity ( ) of > 1 x10^ S/m, alternatively K≥ 2.0x10^ S/m, alternatively K

≥ 5.0x10⁶ S/m, alternatively K≥ 1 .0x10⁷ S/m. The silver particles, and the Ag-coated core particles when present, independently may be in the shape of cuboidals, flakes, granules, irregulars, rods, needles, powders, spheres, or a mixture of any two or more of cuboidals, flakes, granules, irregulars, rods, needles, powders, and spheres. The silver particles may have a median particle size of from 0.005 to 20 microns (μιη). The silver particles may be characterizable by a maximum particle size of 500 μιη, alternatively 200 μιη, alternatively 100 μιη, alternatively 50 μιη, alternatively 30 μιη; and a minimum particle size of 0.0001 μιη, alternatively 0.0005 μιη, alternatively 0.001 μιη. The Ag-coated core particles may have a median particle size of from 5 to 100 μιη. The Ag-coated core particles may be characterizable by a maximum particle size of 1 millimeter (mm), alternatively 100 μιη, alternatively 50 μιη, alternatively 10 μιη, alternatively 1 μιη, alternatively 500 nanometers (nm); and a minimum particle size of > 0.001 μιη, alternatively 0.01 μιη, alternatively 0.1 μιη. The particle sizes may be determined by particle size distribution analysis and reported as a median particle size in μιη (D<50), alternatively as the diameter in μιη below which 10% (D10), 50% (D50) and 90% (D90) of the cumulative particle size distribution is found. Prior to preparing the curable silicone, the particle size may be determined with a sample of Ag particles or Ag-coated core particles in dry form or dispersed in a dispersant (e.g., water) using laser diffraction or particle size analyzer instrument. For example, the MALVERN MASTERSIZER S particle size analyzer instrument (Malvern Instruments, Malvern, Worcestershire, UK) may be used with particles having a size in the range of from 300 nm to 1000 μιη; and the MICROTRAC NANOTRAC UPA150 particle size analyzer instrument (Microtrac, Inc., Montgomeryville, Pennsylvania, USA) may be used with particles having a size in the range of from 5 nm to 4 μιη. Atomic force microscopy (AFM), scanning electron microscopy (SEM) or transmission electron microscopy (TEM) may be used to measure the particle sizes of Ag particles and/or Ag-coated core particles after the particles have been dispersed in the curable silicone or after curing same to the ECSA. Unless stated otherwise herein, any particle size measurement is for particles prior to preparing the curable silicone containing same.

[036] The silver particles (e.g., silver flakes), and the Ag-coated core particles when present, independently may be surface treated. For example, such particles may be surface treated to improve "wetability" by the curable organosiloxane and/or dispersability in the curable silicone, ECSA, or both. The surface treatment may comprise contacting the particles with a chemical substance such as an acid, base, compatibilizer, lubricant, or processing aid. The chemical substance may be aqueous sodium hydroxide, a (C4-C28)carboxylic acid or ester (e.g., a fatty acid or fatty acid ester), the hydrocarbon vehicle, a silicon-containing compound, or sulfuric acid. The silicon-containing compound may be an organochlorosilane, organosiloxane, organodisilazane, organoalkoxysilane. The lubricant may be used to treat the silver particles during a milling process of making silver flakes from silver powder to prevent the silver powder from cold welding or forming agglomerates. The chemical substance may, alternatively may not, be removed from the silver particles and/or the Ag-coated core particles before the particles are mixed with other ingredients of the curable silicone. Even if the treated particles are washed with solvent after the treating process, some chemical substances such as the lubricant or compatibilizer may remain chemisorbed on the surface of the particles.

[037] The "enhancing filler" is any filler lacking highly electrically conductive metal and that increases electrical conductivity and/or decreases volume resistivity of the curable silicone compared to electrical conductivity and/or volume resistivity of a comparative curable silicone lacking the enhancing filler. The enhancing filler may enable the curable silicone and ECSA prepared therefrom to have a volume resistivity of less than 0.0030 Ω- cm, alternatively < 0.0020 Ω-cm , alternatively < 0.0010 Ω-cm , alternatively < 0.00090 Ω- cm, alternatively < 0.00080 Ω-cm, alternatively < 0.00060 Ω-cm, despite having a total concentration of silver in the curable silicone of from 19.5 to 43 wt% and a total concentration of electrically conductive metal of < 75 wt% and wherein the only highly electrically conductive metal is silver. Examples of the enhancing filler are metal particles of tin, molybdenum, zinc, bismuth, indium , lithium, tungsten, nickel, iron, palladium, platinum , or a metal alloy or combination of any two or more of the foregoing metals; carbon nanotubes; electrically non-conductive filler particles; or a combination of any two or more of the metal particles, carbon nanotubes, and electrically non-conductive filler particles.

[038] The carbon nanotubes used in the present invention may be single-walled carbon nanotubes; multi-walled carbon nanotubes; derivatized single-walled carbon nanotubes; derivatized multi-walled carbon nanotubes; or a mixture of any two or more of the single- walled carbon nanotubes, multi-walled carbon nanotubes, derivatized single-walled carbon nanotubes, and derivatized multi-walled carbon nanotubes. The carbon nanotubes may be characterizable by an electrical conductivity (K) of > 1 S/m. The enhancing filler may consist of carbon nanotubes. The "single-walled carbon nanotube" (SWCNT) is an allotrope of carbon having single cylindrical structure (i.e., cylindrical graphene). The "multi- walled carbon nanotubes" (MWCNT) is an allotrope of carbon having multiple sheets of graphite (graphene sheets) in form of coaxial (concentric) cylindrical structures (cylinder within cylinder ("Russian Doll model")) or having a single sheet of graphite (graphene sheet) rolled around itself to form a rolled scroll-like structure ("Parchment model"), or a combination thereof. The CNT may or may not have a "bamboo-like" structure, which may be prepared by chemical vapor deposition pyrolysis of melamine under argon atmosphere at 800° to 980° C. The "derivatized carbon nanotube" is a graphenated carbon nanotube, a functional group-containing carbon nanotube, or a combination structure thereof. The functional group-containing CNT has at least one heteroatom-containing moiety that is covalently bonded to a carbon atom of the carbon nanotube wall wherein the moiety has at least one heteroatom that is O, N, S, P, or halogen (F, CI, Br, or I). Examples of such functional groups are -NO3, -SO3H, -PO3H, -OH, -COOH, and -NH2. The "graphenated carbon nanotube" is a hybrid structure comprising a graphitic foliate covalently bonded to a sidewall of a SWCNT or MWCNT. The functional group-containing carbon nanotubes may be obtained from a commercial supplier thereof or prepared according to any suitable method. Examples of the suitable method comprise exposing a starting carbon nanotube with a chemical substance, an environmental condition, or any combination thereof so as to install the at least one functional group on a carbon atom of the starting carbon nanotubes to give the functional group-containing carbon nanotubes. The chemical substance may be an aqueous base such as aqueous sodium hydroxide; aqueous acid such as sulfuric acid, nitric acid, or a mixture thereof; an oxidant (e.g., oxygen gas); or a mixture thereof. The environmental condition may be heat treatment (e.g., 900° to 1 ,100° C for from 1 to 60 minutes), inert atmosphere, or any combination thereof, graphenated carbon nanotube may be obtained from a commercial supplier thereof or prepared according to any suitable method. Examples of the suitable method comprise any one of the methods of Yu, K., et al. (Carbon Nanotube with Chemically Bonded Graphene Leaves for Electronic and Optoelectronic Applications, J. Phys. Chem. Lett., 201 1 ;13(2): 1556-1562); Stoner, B. R. et al. (Graphenated carbon nanotubes for enhanced electrochemical double layer capacitor performance, Appl. Phys. Lett., 201 1 ;99(18):183104-1 to 183104-3); and Hsu, H-C et al.. (Stand-up structure of graphene-like carbon nanowalls on CNT directly grown on polyacrylonitrile-based carbon fiber paper as supercapacitor, Diamond and Related Materials, 2012;25:176-179). Examples of the combination structure are -NO3, -SO3H,

-PO3H, -OH, -COOH, or -NH2 functionalized graphenated carbon nanotubes such as wherein the -NO3, -SO3H, -PO3H, -OH, -COOH, or -NH₂ groups comprise from 0.01 to 5 wt%, alternatively from 0.1 to 3 wt%, alternatively from 0.5 to 2 (e.g., 1 wt%) of the weight of the combination structure.

[039] Each of the different types of carbon nanotubes particles independently may be characterizable by a maximum outer diameter of 10 μιη, alternatively 1 μιη, alternatively 500 nm, alternatively 300 nm, alternatively 200 nm, alternatively 100 nm, alternatively 50 nm; and a minimum outer diameter of 1 nm, alternatively 2 nm, alternatively 5 nm, alternatively 8 nm, alternatively 10 nm, alternatively 15 nm, alternatively 25 nm. The carbon nanotubes particles may be characterizable by a maximum length of 1 mm, alternatively 500 μιη, alternatively 300 μιη, alternatively 150 μιη, alternatively 100 μιη, alternatively 50 μιη, alternatively 25 μιη; and a minimum length of 0.1 μιη, alternatively 1 μιη, alternatively 5 μιη. , alternatively 10 μιη, alternatively 20 μιη. Raman spectroscopy, AFM, SEM or TEM may be used to measure the diameter and length.

[040] The carbon nanotubes may be dispersed in the curable organosiloxane of the curable silicone by any suitable means such as mixing, sonication, or a combination thereof. The concentration of the carbon nanotubes, when present, in the curable silicone may be from > 0 to 5.0 wt% (e.g., an embodiment of aspect 1 described later), alternatively from 0.01 to 4.9 wt%, alternatively from 0.05 to 3.9 wt%, alternatively from 0.1 to 2.9 wt%, alternatively from 0.4 to 2.5 wt%, alternatively from 0.6 to 2.3 wt%, alternatively from 0.7 to 2.2 wt%, for example from 0.4 to 2.2 wt% or from 0.50 to 2.0 wt%, all based on weight of the curable silicone. Advantageously, the concentration of the carbon nanotubes, when present, in the curable silicone may be varied within the foregoing ranges to adjust rheology such as thixotropic index while beneficially maintaining volume resistivity of the resulting ECSA below 0.003 Ω-cm without adding gold or copper, alternatively copper, gold or aluminum (whether discrete elements or in metal alloys or blends); and while maintaining the total concentration of silver in the attractive range of from 19.5 to 43 wt% in the curable silicone.

[041] The metal particles of tin, molybdenum, zinc, bismuth, indium, lithium, tungsten, nickel, iron, palladium, or platinum respectively mean a finely divided solid form of the element having atomic number 50 (Sn), 42 (Mo), 30 (Zn), 83 (Bi), 49 (In), 3 (Li), 74 (W), 28 (Ni), 26 (Fe), 46 (Pd), or 78 (Pt), respectively. The enhancing filler may consist of metal particles of a single one of the foregoing metals, alternatively of an alloy of any two thereof, alternatively an alloy of any three thereof. At least one of the metals of the alloy may be Sn, alternatively Ni. The particles overall have at least 90 atomic percent (at%), alternatively > 95 at%, alternatively > 98 at%, alternatively > 99.99 at% of the element. The metal alloy of any two or more of the foregoing metals means a metallic solid solution of any two or more of the elements. The combination of any two or more of the foregoing metals means a blend of particles of any two or more of the elements and metal alloys. In the curable silicone, when present the metal particles of the enhancing filler are at a maximum concentration, when present, of 70 wt% (e.g., 69 wt%), alternatively from > 0 to 68 wt%, alternatively from 20 to 68 wt%, alternatively from 30 to 67 wt%, alternatively from 38 to 65 wt%, all based on weight of the curable silicone. [042] The "electrically non-conductive filler particles" are finely-divided solids having a volume resistivity (p) at 20° C greater than 100 Ω-cm and an electrical conductivity ( ) at 20° C less than 1 .0 S/m. The enhancing filler may consist of the electrically non-conductive filler particles. The electrically non-conductive filler particles may be silica glass (e.g., soda- lime-silica glass or borosilicate glass), diamond polymorph of carbon, silica, organic polymer, organosiloxane polymer, or a ceramic. The electrically non-conductive filler particles are distinct from the Ag-coated core particles in that the former lack a coating of silver thereon, whereas the latter have a coating of silver thereon. The electrically non- conductive filler particles are distinct from the aforementioned electrically conductive fillers. The electrically non-conductive filler particles may have sufficient size to improve packing of the silver filler in the ECSA such that the ECSA has lower volume resistivity than that of a comparative ECSA having the same concentration of electrically non-conductive filler particles having smaller size. Such sufficient size may be an average particle diameter of the electrically non-conductive filler particles greater than average particle diameter of the silver filler. Spherical silica glass filler particles may beneficially enhance (i.e., decrease) volume resistivity of the resulting ECSA compared to that of an ECSA prepared from an identical curable silicone except lacking the spherical silica glass filler particles. Alternatively or additionally, the spherical silica glass filler particles may beneficially help maintain thickness uniformity of a bondline of the curable silicone, ECSA, or both, wherein the bondline has been disposed on a substrate such as a substrate for an electrical component, and the resulting component experiences above ambient temperature, pressure, or both (e.g., as during a laminating step). Alternatively or additionally, the spherical silica glass filler particles may beneficially penetrate or mechanically abrade away a metal oxide layer (e.g., copper oxide layer) that may have been formed on an exterior surface of a substrate prone to oxidation or on a surface of the silver particles, Ag-coated core particles, or any combination thereof. An example of the substrate prone to oxidation is a copper foil or wire, a surface layer of which copper may spontaneously oxidize in air to form a copper oxide layer. The curable silicone and ECSA may lack, alternatively may further comprise, the electrically non-conductive filler particles. The concentration of the electrically non-conductive filler particles, when present, may be from 0.1 to 10 wt%, alternatively from 0.5 to 8 wt%, all based on weight of the curable silicone.

[043] The metal particles and electrically non-conductive filler particles of the enhancing filler independently may be in the shape of cuboidals, flakes, granules, irregulars, needles, powders, rods, spheres, or a mixture of any two or more of cuboidals, flakes, granules, irregulars, needles, powders, rods, and spheres. The particles may have a median particle size of from 5 to 100 μιη. The particles may be characterizable by a maximum particle size of 1 millimeter, alternatively 100 microns (μιη), alternatively 50 μιη, alternatively 10 μιη, alternatively 1 μιη, alternatively 500 nanometers (nm). Particle size may be measured as described before for measuring Ag particle size.

[044] In the curable silicone, the enhancing filler is at a total concentration of from 30 to 70 wt% (e.g., 30 to 69 wt%), alternatively from 45 to 68 wt%, alternatively from 55 to 68 wt%, alternatively from 58 to 68 wt%, all based on weight of the curable silicone.

[045] The electrically conductive filler other than the silver particles and enhancing filler means any other solid particles characterizable by volume resistivity (p) at 20° C less than 0.001 Ω-cm and electrical conductivity ( ) at 20° C greater than 1 x10⁴ S/m. These other solid particles include particles of non-diamond allotropes of carbon other than carbon nanotubes, particles of calcium; particles of carbon steel (e.g., 1010), grain oriented electrical steel, MANGANIN (Isabellenhutte Heusler GmbH & Co. KG, Dillenburg, Germany), constantan, stainless steel, and nichrome alloy. The non-diamond allotropes of carbon other than carbon nanotubes include amorphous, fibrillar, glassy (vitreous), and graphitic polymorphs of carbon, and do not include (exclude) the diamond polymorph of carbon. The non-diamond allotropes of carbon other than carbon nanotubes also include amorphous, fibrillar, glassy, and graphitic polymorphs of carbon wherein the particles have been derivatized with functional groups (e.g., -COOH or -NH2) and/or treated with a chemical substance (aqueous base such as aqueous sodium hydroxide or aqueous acid such as sulfuric acid, nitric acid, or a mixture thereof) or an environmental condition (e.g., oxidizing and/or heat treatment), or any combination thereof.

[046] The "curable organosiloxane composition" may be any curable organosiloxane such as a condensation curable organosiloxane, free radical curable organosiloxane, or hydrosilylation-curable organosiloxane. The "silicone" includes linear and branched organosiloxanes. The main advantages of the present invention may be achieved with embodiments employing any curable organosiloxane.

[047] Depending on its reactive functional groups, curing or rate of curing of the curable organosiloxane may be enhanced by contacting the curable organosiloxane with a metal- containing catalyst, heat, ultraviolet (UV) light, O2, peroxides, water (e.g., water vapor in air), or a combination thereof. The metal of the metal-containing catalyst may be Sn, Ti, Pt, or Rh. The condensation curable organosiloxane may be hydroxy-functionalized and/or alkoxy-functionalized. Curing or curing rate of the condensation curable organosiloxane may be enhanced by moisture, heat, or heat and moisture. The free radical curable organosiloxane may be alkenyl-functionalized (e.g., vinyl) and/or alkynyl-functionalized. Curing or curing rate of the free radical curable organosiloxane may be enhanced by UV light or peroxides, heat, or both. The hydrosilylation-curable organosiloxane may be alkenyl functionalized (e.g., vinyl) and Si-H functionalized. Curing or curing rate of the hydrosilylation-curable organosiloxane may be enhanced by a hydrosilylation catalyst (e.g., a Pt catalyst), heat, or both hydrosilylation catalyst and heat. Enhancing curing or rate of curing may comprise increasing extent or degree of curing or increasing the rate of curing at a given temperature or decreasing the temperature at which a given rate of curing is achieved.

[048] Each organosiloxane molecule comprises silicon, carbon, hydrogen, and oxygen atoms. As used in "organosiloxane" the term "organo" means a hydrocarbyl, heterohydrocarbyl, or organoheteryl, which groups are collectively referred to herein as organogroups. Each organogroup may be heterohydrocarbyl, alternatively organoheteryl, alternatively hydrocarbyl. The hydrocarbyl, heterohydrocarbyl, and organoheteryl groups are described later. Each organogroup may have from 1 to 20 carbon atoms, e.g., a (C-|-C2o)hyc!iOcarbyl. Each organosiloxane molecule may contain only unsubstituted hydrocarbyl groups (i.e., contain only silicon, carbon, hydrogen atoms bonded to carbon atoms, and oxygen atoms). Alternatively, one or more organosiloxane molecules may be substituted with heterohydrocarbyl, organoheteryl, or a reactive functional group. Each reactive functional group independently may be the alkenyl or alkynyl moiety; Si-H moiety; Si-OH moiety; Si-OR^x moiety, wherein R^x is (C-_| -C-_|o)hydrocarbyl,

-C(0)(C-| -C-| o)hydrocarbyl; or -N=CR¹ R² moiety, wherein each of R¹ and R² independently is (Ci -Cio)hyc!rocarbyl ₀r R¹ and R² are taken together to form a (C2-C1 rj)hydrocarbylene.

[049] Each organosiloxane molecule independently may comprise a silicon-containing base polymer having a linear, branched, cyclic, or resinous structure. For example, each silicon-containing base polymer independently may have a linear structure, alternatively a branched structure, alternatively a cyclic structure, alternatively a resinous structure. Each silicon-containing base polymer independently may be a homopolymer or copolymer. Each silicon-containing base polymer independently may have one or more of the reactive functional groups per molecule. At least some, alternatively most, alternatively substantially all reactive functional groups react during curing of the curable organosiloxane to give the cured organosiloxane. The reactive functional groups independently may be located on the silicon-containing base polymer at terminal, pendant, or terminal and pendant positions. Each organosiloxane molecule of the curable organosiloxane may be a single silicon- containing base polymer, alternatively may comprise two or more silicon-containing base polymers differing from each other in at least one of the following properties: structure, viscosity, average molecular weight, siloxane units, and unit sequence.

[050] The condensation curable organosiloxane may be a diorganosiloxane compound having on average per molecule at least 1 hydroxyl moiety, or a mixture of the diorganosiloxane compound and an organohalogensilicon compound having on average per molecule at least one halogen atom (e.g., CI, F, Br, or I). Alternatively, the condensation curable organosiloxane may be a mixture of the component (A) and component (B) described in US 6,534,581 B1 , at column 3, line 3, to column 4, line 63. (Components (A) and (B) are different than ingredients (A) and (B) described later herein.) The present invention, however, is not limited to this condensation curable organosiloxane.

[051 ] As used in "diorganosiloxane compound" (whether condensation curable or not) the term "diorgano" means a molecule having at least one difunctional (D) unit of formula R2S1O2/2; wherein each R independently is an organogroup. Examples of diorganosiloxane compounds are a polydimethylsiloxane, wherein each organo group of the D units is methyl; poly(ethyl,methyl)siloxane wherein the organo groups of the D units are methyl and ethyl groups as in the D unit of formula CH3(CH3CH2)Si02/2; and poly(methyl,phenyl)siloxane wherein the organo groups of the D units are methyl and phenyl groups as in the D unit of formula CH3(C6H5)Si02/2- The diorganosiloxane compound may have all D units as in a diorganocyclosiloxane compound. Typically, the diorganosiloxane compound further has at least one M, Q, and/or T units. The reactive functional group(s) may be on any one or more of the D units and/or one or more of any M and/or Q units.

[052] The condensation curable organosiloxane may be a diorganosiloxane compound having on average per molecule at least 1 alkenyl moiety. Alternatively, the free radical curable organosiloxane may be the oligomer, polymer, or product of curing the polymerizable monomer described in US 7,850,870 B2, at column 5, line 28, to column 12, line 9. The present invention, however, is not limited to this free radical curable organosiloxane.

[053] Typically, the curable silicone and its curable organosiloxane comprises the hydrosilylation-curable organosiloxane and after curing the ECSA comprises an at least partially hydrosilylation cured organosiloxane. The present invention, however, is not limited to using hydrosilylation-curable/cured organosiloxanes.

[054] Before at least partial curing, a first embodiment of the hydrosilylation-curable organosiloxane typically comprises ingredients (A) and (C) when ingredient (A) contains a Si-H moiety. Alternatively a second embodiment of the hydrosilylation-curable organosiloxane typically comprises ingredients (A), (B) and (C) when ingredient (A) contains or lacks a Si-H moiety. Ingredients (A) to (C) are: (A) at least one diorganosiloxane compound having an average of at least one unsaturated carbon-carbon bonds per molecule; (B) an organohydrogensilicon compound having an average of at least one Si-H moieties per molecule; and (C) a hydrosilylation catalyst. Ingredient (B) may function as a chain extender or crosslinker for extending or crosslinking ingredient (A).

[055] As used in "organohydrogensilicon compound" (whether hydrosilylation curable or not) the term "organohydrogen" means a molecule having at least one difunctional unit of formula RHSi, wherein R independently is an organogroup. When the organohydrogensilicon compound is an organohydrogensiloxane compound, the molecule has the difunctional (D) unit of formula RHS1O2/2; wherein R independently is an organogroup.

[056] During hydrosilylation curing, different molecules of ingredient (A) in the first embodiment, or ingredients (A) and (B) in the second embodiment, react together via hydrosilylation to give the at least partially hydrosilylation cured organosiloxane. The reaction may give substantial curing; alternatively complete curing. The hydrosilylation cured organosiloxane may be substantially cured, alternatively completely cured. Substantially cured means a degree of curing that is at least 90 mole%, alternatively at least 95 mole%, alternatively at least 98 mole% cured based on the limiting ingredient. The degree of curing may be determined by Differential Scanning Calorimetry (DSC). A fully cured material would not show an exotherm peak by DSC analysis when a sample of the fully cured material is heated during the DSC measurement. An uncured material that is capable of curing would show an exotherm peak (e.g., indicative of an exothermic event such as a reaction or mixing that generates or releases heat) having a maximum area for the uncured material by DSC analysis when a sample of the uncured material is heated during the DSC measurement. A partially cured material would show an exotherm peak wherein the area thereof would be intermediate between the area of the exotherm peak for the uncured material and the 0 area (no exotherm peak) for the cured material. The proportion of area of the exotherm peak of the partially cured material compared to the area of the exotherm peak of the uncured material would be proportional to the percent curing of the partially cured material. Each diorganosiloxane compound and organohydrogensilicon compound independently may be the same (i.e., have both Si-H and unsaturated carbon-carbon bonds in same molecule), alternatively different. When ingredients (A) and (B) are the same compound, the curing comprises intermolecular hydrosilylations and may also comprise intramolecular hydrosilylations. When ingredients (A) and (B) are different compounds, the curing comprises intermolecular hydrosilylations.

[057] Ingredient (A), the at least one diorganosiloxane compound, is hydrosilylation- curable and may include a single diorganosiloxane compound, or a plurality of different diorganosiloxane compounds. As suggested in the foregoing paragraph, each diorganosiloxane compound may contain, alternatively lack a Si-H moiety. Each diorganosiloxane compound independently may have an average of at least 1 , alternatively > 1 , alternatively > 2, alternatively > 3, alternatively > 5, alternatively > 10 unsaturated carbon-carbon bonds per molecule. Each unsaturated carbon-carbon bond independently is C=C (alkenyl) or C≡C (alkynyl). Typically at least one of the unsaturated carbon-carbon bonds is C=C, alternatively all of the unsaturated carbon-carbon bonds are C=C, alternatively at least one of the unsaturated carbon-carbon bonds is C≡C, alternatively all are C≡C, alternatively the unsaturated carbon-carbon bonds are a combination of C=C and C≡C. The diorganosiloxane compound may be an alkynyl siloxane or alkenyl siloxane wherein there are at least one alkynyl or alkenyl groups, respectively, and each of the alkynyl or alkenyl groups may be pending from a carbon, oxygen, or silicon atom. Each alkenyl group independently may have one or more C=C bonds. Each alkenyl may have one C=C and be a (C2-Cg)alkenyl, alternatively ^-C^alkenyl (e.g., vinyl or allyl). The

C=C bond in the alkenyl may be internal as in 5-hexen-1 -yl or terminal alkenyl as in H₂C=C(H)-(C₀-C₆)alkylene (H₂C=C(H)-(C₀)alkylene is vinyl). The alkynyl and alkenyl groups independently may be located at any interval and/or location in the diorganosiloxane compound such as terminal, pendant, or both terminal and pendant (internal) positions. The diorganosiloxane compound(s) may be a mixture or blend of at least two different diorganosiloxane compounds, so long as ingredient (A) has the average of at least one unsaturated carbon-carbon bonds per molecule. The diorganosiloxane compound may be a diorganocyclosiloxane monomer or a polydiorganosiloxane.

[058] Referring again to ingredient (A), the polydiorganosiloxane may be straight or branched, uncrosslinked or crosslinked and comprise at least two D units. Any polydiorganosiloxane may further comprise additional D units. Any polydiorganosiloxane may further comprise at least one M, T, or Q unit in any covalent combination; alternatively at least one M unit; alternatively at least one T unit; alternatively at least one Q unit; alternatively any covalent combination of at least one M unit and at least one T unit. The polydiorganosiloxane with the covalent combination may be a DT, MT, MDM, MDT, DTQ, MTQ, MDTQ, DQ, MQ, DTQ, or MDQ polydiorganosiloxane. Ingredient (A) may be a mixture or blend of polydiorganosiloxanes, e.g., a mixture of MDM and DT molecules. Known symbols M, D, T, and Q, represent the different functionality of structural units that may be present in a siloxane (e.g., a silicone), which comprises siloxane units joined by covalent bonds. The monofunctional (M) unit represents R3S1O1/2; the difunctional (D) unit represents R2S1O2/2; the trifunctional (T) unit represents RS1O3/2 and results in the formation of branched linear siloxanes; and the tetrafunctional (Q) unit represents S1O4/2 and results in the formation of crosslinked and resinous compositions. The reactive group- functional siloxane may be R¹ Si03/2 units (i.e., T units) and/or S1O4/2 units (i.e., Q units) in covalent combination with R¹ R⁴2SiO-|/2 units (i.e., M units) and/or R⁴2SiC>2/2 units (i.e., D units). Each "R" group, e.g., R, R¹ and R⁴ independently is hydrocarbyl, heterohydrocarbyl, or organoheteryl, which are collectively referred to herein as organogroups. Each hydrocarbyl, heterohydrocarbyl, and organoheteryl independently may have from 1 to 20, alternatively from 1 to 10, alternatively from 1 to 8, alternatively from 1 to 6 carbon atoms. Each heterohydrocarbyl and organoheteryl independently comprises carbon, hydrogen and at least one heteroatom that independently may be halo, N, O, S, or P; alternatively S; alternatively P; alternatively halo, N, or O; alternatively halo; alternatively halo; alternatively O; alternatively N. Each heterohydrocarbyl and organoheteryl independently may have up to 4, alternatively from 1 to 3, alternatively 1 or 2, alternatively 3, alternatively 2, alternatively 1 heteroatom (s). Each heterohydrocarbyl independently may be halohydrocarbyl (e.g., fluoromethyl, trifluoromethyl, trifluorovinyl, or chlorovinyl), alternatively aminohydrocarbyl (e.g., H₂N-hydrocarbyl) or alkylaminohydrocarbyl, alternatively dialkylaminohydrocarbyl (e.g., 3-dimethylaminopropyl), alternatively hydroxyhydrocarbyl, alternatively alkoxyhydrocarbyl (e.g., methoxyphenyl). Each organoheteryl independently may be hydrocarbyl-N(H)-, (hydrocarbyl)₂N-, hydrocarbyl- P(H)-, (hydrocarbyl)₂P-, hydrocarbyl-O-, hydrocarbyl-S-, hydrocarbyl-S(O)-, or hydrocarbyl-S(0)2-. Each hydrocarbyl independently may be (C-_| -C8)hydrocarbyl, alternatively (C-_| -Cg)hydrocarbyl, alternatively (C1 -C3) hydrocarbyl, alternatively (C-_| -C2)hyclrocarbyl. Each (C-_| -C8)hydrocarbyl independently may be {CJ-CQ) hydrocarbyl, alternatively (C-_| -Cg) hydrocarbyl. Each (C₇-Cg) hydrocarbyl may be a heptyl, alternatively an octyl, alternatively benzyl, alternatively tolyl, alternatively xylyl. Each (C-_| -Cg)hydrocarbyl independently may be (C-_| -Cg)alkyl, (C2-Cg)alkenyl, (C2-Cg)alkynyl, (C3-Cg)cycloalkyl, or phenyl. Each (C-_| -Cg)alkyl independently may be methyl, ethyl, propyl, butyl, or pentyl; alternatively methyl or ethyl; alternatively methyl; alternatively ethyl. Each halo independently may be bromo, fluoro or chloro; alternatively bromo; alternatively fluoro; alternatively chloro. Each R, R¹ and R⁴ independently may be hydrocarbyl; alternatively halohydrocarbyl; alternatively hydrocarbyl and at least one heterohydrocarbyl; alternatively hydrocarbyl and at least one organoheteryl. There may be an average of at least 1 "R" per molecule having an alkenyl or alkynyl group capable of undergoing hydrosilylation. For example, there may be an average of at most 4, alternatively at least 1 , alternatively >1 , alternatively at least 2, alternatively 3, alternatively from 1 to 4, alternatively from 1 to 3 alkenyl or alkynyl group per diorganosiloxane molecule each independently capable of undergoing hydrosilylation. Examples of suitable alkenyl are vinyl, fluorovinyl, trifluorovinyl, allyl, 4-buten-1 -yl, and 1 -buten-4-yl. Examples of suitable alkynyl are acetylenyl, propyn-3-yl, and 1 -butyn-4-yl.

[059] Referring again to ingredient (A), the polydiorganosiloxane may be a polydialkylsiloxane, e.g., an alkyldialkenylsiloxy-terminated polydialkylsiloxane or a dialkylalkenylsiloxy-terminated polydialkylsiloxane, e.g., a dialkylvinylsiloxy-terminated polydialkylsiloxane. Examples of the dialkylvinylsiloxy-terminated polydialkylsiloxane are dimethylvinylsiloxy-terminated polydimethylsiloxane; diethylvinylsiloxy-terminated polydimethylsiloxane; methyldivinylsiloxy-terminated polydimethylsiloxane; dimethylvinylsiloxy-terminated polydiethylsiloxane; dimethylvinylsiloxy-terminated poly(methyl,ethyl)siloxane; poly(methyl,(C₇-C₈)hydrocarbyl)siloxane; and combinations thereof. Alternatively, the polydiorganosiloxane may be a hydroxy-term inated polydiorganosiloxane. The hydroxy-term inated polydiorganosiloxane may be a hydroxy- terminated polydialkylsiloxane having pendent alkenyl, alkynl, or alkenyl and alkenyl groups. Examples of the hydroxy-term inated polydialkylsiloxane are hydroxy-term inated polydimethylsiloxane having pendent vinyl groups; hydroxy-terminated polydiethylsiloxane having pendent vinyl groups; hydroxy-terminated poly(methyl,ethyl)siloxane having pendent vinyl groups; hydroxy-terminated poly(methyl,(C7-C8)hydrocarbyl)siloxane having pendent vinyl groups; and combinations thereof. Terminated means mono (alpha), alternatively bis (both alpha and omega) termination. Alternatively, any one of the foregoing polydialkylsiloxanes may further comprise one or more (e.g., from 1 to 3) internal (alkyl,alkynyl) units, alternatively internal (alkyl,alkenyl) units (e.g., methyl,vinyl or ethyl.vinyl units) or one or more (e.g., from 1 to 3) alkenyl-containing pendent groups, e.g., a dimethylvinylsiloxy-pendent group-containing polydimethylsiloxane. Alternatively, the polydiorganosiloxane may be an alkenyldialkylsilyl end-blocked polydialkylsiloxane; alternatively a vinyldimethylsilyl end-blocked polydimethylsiloxane. Ingredient (A) may be a polydiorganosiloxane comprising methyl and vinyl R groups. Ingredient (A) may be a poly(methyl,vinyl)siloxane (homopolymer); alternatively a hydroxy-terminated poly(methyl,vinyl)siloxane (homopolymer); alternatively a poly(methyl,vinyl)(dimethyl)siloxane copolymer; alternatively a hydroxy-terminated poly(methyl,vinyl)(dimethyl)siloxane copolymer; alternatively a mixture of any of at least two thereof. A poly(methyl,vinyl)(dimethyl)siloxane copolymer means a molecule having

R¹ ,R⁴Si02/2 units wherein R¹ is methyl and R⁴ is vinyl and R¹ ,R¹ SiC>2/2 units wherein each R¹ is methyl.

[060] Referring again to ingredient (A), the diorganocyclosiloxane monomer may be a

(R¹ ,R⁴)cyclosiloxane, wherein R¹ and R⁴ independently are as defined previously. The

(R¹ ,R⁴)cyclosiloxane may be a (C₇-Cg)hydrocarbyl,alkenyl-cyclosiloxane, (C₇-

C8)hydrocarbyl,alkynyl-cyclosiloxane, alkyl,alkynyl-cyclosiloxane, or a alkyl.alkenyl- cyclosiloxane, wherein (Cy-Cgjhydrocarbyl and alkyl independently are as defined previously. The (alkyl,alkenyl)-cyclosiloxane may be, e.g., a (alkyl,vinyl)-cyclosiloxane, e.g., a methyl,vinyl-cyclosiloxane or (ethyl,vinyl)-cyclosiloxane.

[061] Referring again to ingredient (A), the diorganosiloxane compound may further comprise, alternatively may substantially lack volatile diorganosiloxanes. Reiterated, the diorganosiloxane compound may be used as prepared, with volatile diorganosiloxane components retained; alternatively the as prepared diorganosiloxane compound may be devolatilized to remove a volatile fraction before use in the curable organosiloxane.

[062] Referring again to ingredient (A), the diorganosiloxane compound may have a number-average molecular weight (M_n) of from 500 to 50,000 g/mol, alternatively from 500 to 10,000 g/mol, alternatively 1 ,000 to 3,000, g/mol, where the M_n is determined by gel permeation chromatography employing a low angle laser light scattering detector, or a refractive index detector and silicone resin (MQ) standards. The diorganosiloxane compound may have a dynamic viscosity of from 0.01 to 100,000 Pascal-seconds (Pa.s), alternatively from 0.1 to 99,000 Pa.s, alternatively from 1 to 95,000 Pa.s, alternatively from 10 to 90,000 Pa.s, alternatively from 100 to 89,000 Pa.s, alternatively from 1 ,000 to 85,000 Pa.s, alternatively from 10,000 to 80,000 Pa.s, alternatively from 30,000 to 60,000 Pa.s., alternatively from 40,000 to 75,000 Pa.s., alternatively from 40,000 to 70,000 Pa.s., alternatively from 10,000 to < 40,000 Pa.s, alternatively from 5,000 to 15,000 Pa.s, alternatively from >75,000 to 100,000 Pa.s. The dynamic viscosity is measured at 25° C according to the dynamic viscosity test method described later. The diorganosiloxane compound may have less than 10 wt%, alternatively less than 5 wt%, alternatively less than 2 wt%, of silicon-bonded hydroxyl groups, as determined by 29_S i-NMR. Alternatively, the diorganosiloxane compound may have less than 10 mole percent (mol%), alternatively less than 5 mol%, alternatively less than 2 mol%, of silicon-bonded hydroxyl groups, as determined by ²⁹Si-NMR.

[063] The ingredient (A) (e.g., the diorganosiloxane compound) may be from 1 to 39 wt%, alternatively from 3 to 30 wt%, alternatively from 4 to 20 wt% of the curable silicone. Alternatively, the ingredient (A) may be from 50 to 90 wt%, alternatively from 60 to 80 wt%, alternatively from 70 to 80 wt% of the hydrosilylation-curable organosiloxane.

[064] Ingredient (B), the organohydrogensilicon compound, has at least one silicon- bonded hydrogen atom per molecule. The organohydrogensilicon compound may be a single organohydrogensilicon compound, or a plurality of different organohydrogensilicon compounds. The organohydrogensilicon compound may have organo groups and an average of at least two, alternatively at least three silicon-bonded hydrogen atoms per molecule. Each organo group independently may be the same as R, R¹ , or R⁴ groups as defined before. The organohydrogensilicon compound may be an organohydrogensilane, an organohydrogensiloxane, or a combination thereof. The structure of the organohydrogensilicon compound may be linear, branched, cyclic (e.g., Cyclosilanes and cyclosiloxanes), or resinous. Cyclosilanes and cyclosiloxanes may have from 3 to 12, alternatively from 3 to 10, alternatively 3 or 4 silicon atoms. In acyclic polysilanes and polysiloxanes, the silicon-bonded hydrogen atoms may be located at terminal, pendant, or at both terminal and pendant positions.

[065] Referring to an embodiment of ingredient (B), the organohydrogensilane may be a monosilane, disilane, trisilane, or polysilane (tetra- or higher silane). Examples of suitable organohydrogensilanes are diphenylsilane, 2-chloroethylsilane, bis[(p- dimethylsilyl)phenyl]ether, 1 ,4- dimethyldisilylethane, 1 ,3,5-tris(dimethylsilyl)benzene, 1 ,3,5-trimethyl-1 ,3,5- trisilane, poly(methylsilylene)phenylene, and poly(methylsilylene)methylene.

[066] Referring to an embodiment of ingredient (B), the organohydrogensiloxane may be a disiloxane, trisiloxane, or polysiloxane (tetra- or higher siloxane). The organohydrogensiloxane may be further defined as an organohydrogenpolysiloxane resin, so long as the resin includes at least one silicon- bonded hydrogen atom per molecule. The organohydrogenpolysiloxane resin may be a copolymer including T units, and/or Q units, in combination with M units, and/or D units, wherein T, Q, M and D are as described above. For example, the organohydrogenpolysiloxane resin can be a DT resin, an MT resin, an MDT resin, a DTQ resin, an MTQ resin, an MDTQ resin, a DQ resin, an MQ resin, a DTQ resin, an MTQ resin, or an MDQ resin. The M, D, T and Q units may be the same as those described previously. Examples of suitable organohydrogensiloxanes are 1 ,1 ,3,3- tetramethyldisiloxane, 1 ,1 ,3,3-tetraphenyldisiloxane, phenyltris(dimethylsiloxy)silane, 1 ,3,5- trimethylcyclotrisiloxane, a trimethylsiloxy-terminated poly(methylhydrogensiloxane), a trimethylsiloxy-terminated poly(dimethylsiloxane/methylhydrogensiloxane), a dimethylhydrogensiloxy- terminated poly(methylhydrogensiloxane), and a (H,Me)Si resin. Thus, the organohydrogensilicon compound may be the trimethylsiloxy-terminated poly(dimethylsiloxane/methylhydrogensiloxane).

[067] Referring again to ingredient (B), the organohydrogensilicon compound may have a molecular weight less than 1 ,000, alternatively less than 750, alternatively less than 500 g/mol. The organohydrogensilicon compound may be a dimethylhydrogensilyl terminated polydimethylsiloxane; alternatively a trialkylsilyl terminated polydialkylsiloxane - alkylhydrogensiloxane co-polymer; alternatively a trimethylsilyl terminated polydimethylsiloxane - methylhydrogensiloxane co polymer; alternatively a mixture of a dialkylhydrogensilyl terminated polydialkylsiloxane and a trialkylsilyl terminated polydialkylsiloxane - alkylhydrogensiloxane co-polymer. The dialkylhydrogensilyl terminated polydialkylsiloxane may be a dimethylhydrogensilyl terminated polydimethylsiloxane. The trialkylsilyl terminated polydialkylsiloxane -alkylhydrogensiloxane co-polymer may be a trimethylsilyl terminated polydimethylsiloxane methylhydrogensiloxane co-polymer.

[068] The ingredient (B) (e.g., the organohydrogensilicon compound) may be from 0.1 to 10 wt%, alternatively from 0.2 to 8 wt%, alternatively from 0.3 to 5 wt% of the curable silicone. Alternatively, the ingredient (B) may be from 1 to 10 wt%, alternatively from 2 to 8 wt%, alternatively from 3 to 7 wt% of the hydrosilylation-curable organosiloxane. [069] Referring again to ingredients (A) and (B), the hydrosilylation-curable organosiloxane may have a molar ratio of total silicon-bonded hydrogen atoms to unsaturated carbon-carbon bonds of from 0.05 to 100, alternatively from 0.1 to 100, alternatively from 0.05 to 20, alternatively from 0.5 to 15, alternatively from 1 .5 to 14. When ingredients (A) and (B) are different molecules, the hydrosilylation-curable organosiloxane may have a molar ratio of silicon-bonded hydrogen atoms per molecule of the organohydrogensilicon compound to unsaturated carbon-carbon bonds per molecule of the diorganosiloxane compound of from 0.05 to 100, alternatively from 0.1 to 100, alternatively from 0.05 to 20, alternatively from 0.5 to 14, alternatively from 0.5 to 2, alternatively from 1.5 to 5, alternatively from > 5 to 14. The present invention, however, is not limited to the hydrosilylation-curable organosiloxane comprising ingredients (A) and (B).

[070] Ingredient (C), the hydrosilylation catalyst, is any compound or material useful to accelerate a hydrosilylation reaction between the diorganosiloxane compound and the organohydrogensilicon compound. The hydrosilylation catalyst may comprise a metal; a compound containing the metal; or any combination thereof. Each metal independently be platinum, rhodium, ruthenium, palladium, osmium, or iridium, or any combination of at least two thereof. Typically, the metal is platinum, based on its high activity in hydrosilylation reactions. Typically ingredient (C) is the platinum compound. Examples of suitable platinum hydrosilylation catalysts are complexes of chloroplatinic acid and certain vinyl-containing organosiloxanes in US 3,419,593 such as the reaction product of chloroplatinic acid and l,3-diethenyl-l,l,3,3-tetramethyldisiloxane. The hydrosilylation catalyst may be unsupported or disposed on a solid support (e.g., carbon, silica, or alumina). The hydrosilylation catalyst may be microencapsulated in a thermoplastic resin for increased stability during storage of the curable silicone comprising the hydrosilylation-curable organosiloxane before curing. When curing is desired, the microencapsulated catalyst (e.g., see US 4,766,176 and US 5,017,654) may be heated about the melting or softening point of the thermoplastic resin, thereby exposing the hydrosilylation catalyst to ingredients (A) and (B). The hydrosilylation catalyst may be a photoactivatable catalyst (e.g., platinum(ll) β- diketonate complexes such as platinum(ll) bis(2,4-pentanedionate)) for increased stability during storage of the curable silicone before curing. When curing is desired, the photoactivatable catalyst may be exposed to ultraviolet radiation having a wavelength of from 150 to 800 nanometers (nm), thereby activating the catalyst to the hydrosilylation reaction of ingredients (A) and (B).

[071] Ingredient (C) typically is employed in a catalytically effective amount. The catalytically effective amount of the hydrosilylation catalyst is any quantity sufficient to catalyze, increase the rate of hydrosilylation of the diorganosiloxane compound and organohydrogensilicon compound. A suitable concentration of the unsupported and unencapsulated hydrosilylation catalyst in the hydrosilylation-curable organosiloxane is from 0.1 to 1000 parts per million (ppm), alternatively from 1 to 500 ppm, alternatively from 3 to 150 ppm, alternatively from 1 to 25 ppm, based on the combined weight of ingredients (A) to (C). A suitable concentration of the microencapsulated hydrosilylation catalyst in the hydrosilylation-curable organosiloxane is from 1 to 20 wt%, alternatively from 3 to 17 wt%, alternatively from 5 to 15 wt%, alternatively from 10 to 15 wt%, based on the combined weight of ingredients (A) to (C).

[072] Optional ingredients. As described earlier, the curable silicone comprises the following original ingredients: the hydrocarbon vehicle, curable organosiloxane, and the electrically conductive filler consisting essentially of a combination of the silver filler and enhancing filler. In some embodiments the curable silicone and ECSA lack additional ingredients. The term "lack" means contains less than the minimum concentration of; alternatively is completely free of, does not contain (e.g., contains 0.000 wt% of), or does not include any. However, whether curable by hydrosilylation, condensation, free radical, or other chemistry, it may be desirable for the curable silicone and ECSA to further comprise at least one additional ingredient that is distinct from the original ingredients. The at least one additional ingredient should not affect the basic and novel characteristics of the present invention, e.g., achieving one or more of the advantages described herein for the curable silicone and ECSA.

[073] When the optional ingredient is an organosiloxane, the organosiloxane comprises one or more organogroups. Each organogroup independently may be an alkyl, alkenyl, alkynyl, aryl, or organoheteryl. The organogroups are covalently bonded directly to a silicon atom of the organosiloxane. The alkyl groups of the organogroups independently may have from 1 to 6, alternatively from 1 to 3 carbon atoms; alternatively the alkyl may be methyl, alternatively ethyl, alternatively propyl. The alkenyl and alkynyl of the organogroups independently may have from 2 to 6, alternatively from 2 to 4 carbon atoms; alternatively the alkenyl may be vinyl, alternatively propen-3-yl, alternatively buten-4-yl; and alternatively the alkynyl may be acetylenyl, alternatively propyn-3-yl, alternatively butyn-4-yl. The aryl of the organogroups may be phenyl, alternatively naphthyl. The organoheteryl of the organogroups may have from 1 to 5, alternatively from 1 to 3 carbon atoms and at least one heteroatom that is O, S, or N; alternatively O or N; alternatively O; alternatively N; alternatively the organoheteryl may be alkyl-O-alkylene, alternatively dialkyl-N-alkylene; alternatively methyl-O-ethylene, alternatively methyl-O-propylene. [074] In some embodiments the curable silicone and ECSA further comprise the at least one additional ingredient. The amount of the at least one additional ingredient, when present in the curable silicone, or the curable silicone and ECSA prepared therefrom, is not so high as to prevent the curable silicone from satisfying at least the minimum concentrations of the original ingredients or prevent the ECSA from satisfying its limitations such as volume resistivity, total silver concentration, and other functions and concentrations as described herein. When present in the curable silicone, the at least one additional ingredient may be at a total concentration of 0.01 to 15 wt% based on total weight of the curable silicone. When present, the total concentration of all the additional ingredients is from 0.1 to 12 wt%, alternatively from 1 to 10 wt%.

[075] The curable silicone may be prepared with the at least one additional ingredient in any suitable manner. For example, the at least one additional ingredient may be premixed with the curable organosiloxane or a diorganosiloxane ingredient thereof. The resulting premixture may then be blended with the hydrocarbon vehicle, any other ingredients of the curable organosiloxane, and electrically conductive filler to prepare embodiments of the curable silicone wherein the blend further comprises the at least one additional ingredient.

[076] Typically, the at least one additional ingredient includes an adhesion promoter, more typically an organosiloxane adhesion promoter. Alternatively or additionally, the at least one additional ingredient may be one or more of a silicone extender, organic plasticizer, or a combination of silicone extender and organic plasticizer; a cure inhibitor; a defoamer; a biocide; a chain lengthener; a chain endblocker; an anti-aging additive; an acid acceptor; and a combination of any two or more selected from the immediately foregoing listing (i.e., the listing from the silicone extender to the acid acceptor). Alternatively, the at least one additional ingredient may be a combination of the adhesion promoter and any one or more selected from the immediately foregoing listing from the silicone extender to the acid acceptor. For example, the adhesion promoter may be used in combination with the silicone extender, cure inhibitor, or both. The at least one additional ingredient may be the adhesion promoter, alternatively the silicone extender, alternatively the organic plasticizer, alternatively the combination of silicone extender and organic plasticizer, alternatively the cure inhibitor, alternatively the defoamer, alternatively the biocide, alternatively the chain lengthener, alternatively the chain endblocker, alternatively the anti- aging additive, alternatively the acid acceptor, alternatively any one of the combinations. Additionally, it is convenient to name optional ingredients by an intended use of the optional ingredient in the curable silicone and/or ECSA. The intended use, however is not limiting of the chemistry of the so-named optional ingredient and does not restrict how the so-named optional ingredient may react or function during curing of the curable silicone to give the ECSA. To illustrate, a so-called adhesion promoter may function in the curable silicone and/or ECSA as an adhesion promoter and optionally as a chain lengthener, crosslinker, silicone extender, or any combination of adhesion promoter and one or more of chain lengthener, crosslinker and silicone extender.

[077] The adhesion promoters useful in the present invention may comprise a metal chelate, a silicon-based adhesion promoter, or a combination of any two or more thereof. The combination may be a combination of the metal chelate and at least one silicon-based adhesion promoter or a combination of at least two different silicon-based adhesion promoters. The different silicon-based adhesion promoters differ from each other in at least one of the following properties: structure, viscosity, average molecular weight, siloxane units, and unit sequence. Further, the silicon-based adhesion promoters differ from other silicon-based ingredients of the curable organosiloxane (e.g., ingredients (A) and (B) of the embodiment(s) of the hydrosilylation-curable organosiloxane) in at least one of the following properties: structure, viscosity, average molecular weight, siloxane units, and unit sequence. In some embodiments the curable silicone and ECSA lack the adhesion promoter; in other embodiments they further comprise the adhesion promoter.

[078] The metal chelate adhesion promoter may be based on a metal that is lead, tin, zirconium, antimony, zinc, chromium, cobalt, nickel, aluminum, gallium, germanium, or titanium. The metal chelate may comprise the metal cation and an anionic chelating ligand such as a monocarboxylate, dicarboxylate, or alkoxide. The adhesion promoter may comprise a non-transition metal chelate such as an aluminum chelate such as aluminum acetylacetonate. Alternatively, the metal chelate may be a transition metal chelate. Suitable transition metal chelates include titanates, zirconates such as zirconium acetylacetonate, and combinations thereof. The metal chelate may be the titanium chelate. Alternatively, the adhesion promoter may comprise a combination of a metal chelate with an alkoxysilane, such as a combination of glycidoxypropyltrimethoxysilane with an aluminum chelate or a zirconium chelate. Alternatively, the metal chelate may lack silicon. Example of suitable metal chelates are mentioned in US 4,680,364 at column 3, line 65, to column 6, line 59.

[079] Typically, the adhesion promoter is the silicon-based adhesion promoter. Suitable silicon-based adhesion promoters include a hydrocarbyloxysilane, a combination of an alkoxysilane and a hydroxy-functional polyorganosiloxane, an aminofunctional silane, or a combination of any two or more thereof. The hydrocarbyloxysilane may be an alkoxysilane. [080] For example, the adhesion promoter may comprise a silane having the formula R19_RR20_ssi(OR²¹ )4_(_{R + s}) where each R^{1 9} is independently a monovalent organic group having at least 3 carbon atoms; R²⁰ contains at least one Si-C-substituent wherein the substituent has an adhesion-promoting group, such as amino, epoxy, mercapto or acrylate groups; each R²¹ is independently a saturated hydrocarbon group; subscript r has a value ranging from 0 to 2; subscript s is either 1 or 2; and the sum of (r + s) is not greater than 3.

Saturated hydrocarbon groups for R²¹ may be an alkyl group of 1 to 4 carbon atoms, alternatively alkyl of 1 or 2 carbon atoms. R²¹ may be methyl, ethyl, propyl, or butyl;

alternatively R²¹ may be methyl. Alternatively, the adhesion promoter may comprise a partial condensate of the above silane. Alternatively, the adhesion promoter may comprise a combination of an alkoxysilane and a hydroxy-functional polyorganosiloxane.

[081] Alternatively, the adhesion promoter may comprise an unsaturated or epoxy- functional compound. The adhesion promoter may comprise an unsaturated or epoxy- functional alkoxysilane. For example, the functional alkoxysilane can have the formula R²²tSi(OR²³)(4-t), where subscript t is 1 , 2, or 3, alternatively subscript t is 1 . Each R22 is independently a monovalent organic group with the proviso that at least one R²2 is an unsaturated organic group or an epoxy-functional organic group. Epoxy-functional organic groups for R²2 are exemplified by 3-glycidoxypropyl and (epoxycyclohexyl)ethyl.

Unsaturated organic groups for R²2 are exemplified by 3-methacryloyloxypropyl, 3- acryloyloxypropyl, and unsaturated monovalent hydrocarbon groups such as vinyl, allyl, hexenyl, undecylenyl. Each R²3 j_s independently a saturated hydrocarbon group of 1 to 4 carbon atoms, alternatively 1 to 2 carbon atoms. R²³ is exemplified by methyl, ethyl, propyl, and butyl.

[082] Examples of suitable epoxy-functional alkoxysilane type adhesion promoters include 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane,

(epoxycyclohexyl)ethyldimethoxysilane, (epoxycyclohexyl)ethyldiethoxysilane and combinations thereof. Examples of suitable unsaturated alkoxysilanes include vinyltrimethoxysilane, allyltrimethoxysilane, allyltriethoxysilane, hexenyltrimethoxysilane, undecylenyltrimethoxysilane, 3-methacryloyloxypropyl trimethoxysilane, 3- methacryloyloxypropyl triethoxysilane, 3-acryloyloxypropyl trimethoxysilane, 3- acryloyloxypropyl triethoxysilane, and combinations thereof. [083] Alternatively, the adhesion promoter may comprise an epoxy-functional organosiloxane such as a reaction product of a hydroxy-terminated polyorganosiloxane with an epoxy-functional alkoxysilane, as described above, or a physical blend of the hydroxy-terminated polyorganosiloxane with the epoxy-functional alkoxysilane. The epoxy- functional organosiloxane comprises one or more, alternatively two or more epoxy groups and at least one type of organogroup such as the alkyl, alkenyl, alkynyl, aryl, or organoheteryl. The epoxy group(s) independently may be covalently bonded directly to a silicon atom of the organosiloxanyl portion of the epoxy-functional organosiloxane or to any carbon atom of the organogroup. The epoxy group(s) may be located at internal, terminal, or both positions of the organosiloxanyl portion. The epoxy-functional organosiloxane may be an epoxy-functional diorganosiloxane, an epoxy-functional organo,hydrogensiloxane; or an epoxy-functional diorgano/(organo,hydrogen)siloxane. The

"diorgano/(organo, hydrogen)" indicates the siloxane has both diorganoSi D units ("D") and organo-SiH D units (D^H) in the organosiloxanyl portion. The organogroups in any one of such diorganoSi D units may be the same as or different from each other. For example, the epoxy-functional diorganosiloxane may be a bis(alpha,omega-glycidoxyalkyl)- dialkyl/(alkyl,alkenyl)siloxane. The "dialkyl/(alkyl,alkenyl)" indicates siloxane has both dialkyISi D units and alkyl, alkenyISi D units. The "bis(alpha,omega-glycidoxyalkyl)" indicates a dialkyl/alkyl,alkenylsiloxanyl moiety has two terminal glycidoxyalkyl groups, and 0 or optionally 1 or more internal glycidoxyalkyl groups. Alternatively, the adhesion promoter may comprise a combination of an epoxy-functional alkoxysilane and an epoxy- functional siloxane. For example, the adhesion promoter is exemplified by a mixture of 3- glycidoxypropyltrimethoxysilane and a reaction product of hydroxy-terminated methylvinylsiloxane (i.e., hydroxy-terminated poly(methyl,vinyl)siloxane) with 3- glycidoxypropyltrimethoxysilane, or a mixture of 3-glycidoxypropyltrimethoxysilane and a hydroxy-terminated methylvinylsiloxane, or a mixture of 3-glycidoxypropyltrimethoxysilane and a hydroxy-terminated methylvinyl/dimethylsiloxane copolymer.

[084] Alternatively, the adhesion promoter may comprise an epoxy-functional organocyclosiloxane. The epoxy-functional organocyclosiloxane comprises one or more, alternatively two or more epoxy groups and at least one type of organogroup such as the alkyl, alkenyl, alkynyl, aryl, or organoheteryl. For example, the epoxy-functional organocyclosiloxane may be an epoxy-functional D3 to D6 diorganocyclosiloxane; an epoxy-functional D3 to D6 organo,hydrogencyclosiloxane; or an epoxy-functional D3 to D6 diorgano/(organo,hydrogen)cyclosiloxane. The D3 is an organocyclotrisiloxane; D4 is an organocyclotetrasiloxane; D5 is an organocyclopentasiloxane; and D6 is an organocyclohexasiloxane. The epoxy-functional organocyclosiloxane may have one or more, alternatively two or more organocyclosiloxanyl moieties, wherein any two organocyclosiloxanyl moieties may be linked to each other via an alkylene- diorganosiloxanylene-alkylene chain. For example, the epoxy-functional D3 to D6 organo,hydrogencyclosiloxane may be a bis(alpha,omega-glycidoxyalkyl-D3 to D6 organo,hydrogencyclosiloxane), wherein there are at least two glycidoxyalkyl moieties; there are at least two organo,hydrogencyclosiloxanyl moieties, which may be the same as or different from each other; and any two organo,hydrogencyclosiloxanyl moieties independently are linked to each other via an alkylene-diorganosiloxanylene-alkylene chain. The alkyl may be methyl and the alkenyl may be vinyl. Each chain may be the same as or different from each other, may be linear or branched, and may have a backbone of from 3 to 100, alternatively from 5 to 90, alternatively from 8 to 50 atoms, wherein the backbone atoms are C, Si, and O. The epoxy group(s) independently may be covalently bonded directly to a silicon atom of the organocyclosiloxanyl moiety or, when there are two or more organocyclosiloxanyl moieties, to a silicon atom of the alkylene- diorganosiloxanylene-alkylene chain; or the epoxy group(s) may be covalently bonded directly to any carbon atom of any organogroup thereof. The groups in any D unit may be the same as or different from each other.

[085] Alternatively, the adhesion promoter may comprise an aminofunctional silane, such as an aminofunctional alkoxysilane exemplified by H₂N(CH₂)₂Si(OCH₃)3,

H₂N(CH₂)₂Si(OCH₂CH₃)₃, H₂N(CH₂)₃Si(OCH₃)₃, H₂N(CH₂)₃Si(OCH₂CH₃)₃,

CH₃NH(CH₂)₃Si(OCH₃)₃, CH₃NH(CH₂)₃Si(OCH₂CH₃)₃, CH₃NH(CH₂)₅Si(OCH₃)₃,

CH₃NH(CH₂)₅Si(OCH₂CH₃)₃, H₂N(CH₂)₂NH(CH₂)₃Si(OCH₃)₃,

H₂N(CH₂)₂NH(CH₂)₃Si(OCH₂CH₃)₃, CH₃NH(CH₂)₂NH(CH₂)₃Si(OCH₃)₃,

CH₃NH(CH₂)₂NH(CH₂)₃Si(OCH₂CH₃)₃, C₄H₉NH(CH₂)₂NH(CH₂)₃Si(OCH₃)₃,

C₄H₉NH(CH₂)₂NH(CH₂)₃Si(OCH₂CH₃)₃, H₂N(CH₂)₂SiCH₃(OCH₃)₂,

H₂N(CH₂)₂SiCH₃(OCH₂CH₃)₂, H₂N(CH₂)₃SiCH₃(OCH₃)₂, H₂N(CH₂)₃SiCH₃(OCH₂CH₃)₂, CH₃NH(CH₂)₃SiCH₃(OCH₃)₂, CH₃NH(CH₂)₃SiCH₃(OCH₂CH₃)₂, CH₃NH(CH₂)₅SiCH₃(OCH₃)₂, CH₃NH(CH₂)₅SiCH₃(OCH₂CH₃)₂, H₂N(CH₂)₂NH(CH₂)₃SiCH₃(OCH₃)₂,

H₂N(CH₂)₂NH(CH₂)₃SiCH₃(OCH₂CH₃)₂, CH₃NH(CH₂)₂NH(CH₂)₃SiCH₃(OCH₃)₂,

CH₃NH(CH₂)₂NH(CH₂)₃SiCH₃(OCH₂CH₃)₂, C₄H₉NH(CH₂)₂NH(CH₂)₃SiCH₃(OCH₃)₂,

C₄H₉NH(CH₂)₂NH(CH₂)₃SiCH₃(OCH₂CH₃)₂, and a combination thereof.

[086] The concentration of adhesion promoter, when present, may be from 0.1 to 10 wt%, alternatively from 0.5 to 7 wt%, alternatively from 0.7 to 5 wt%, all based on weight of the curable silicone. Alternatively, the concentration of adhesion promoter, when present, may be from 1 to 10 wt%, alternatively from 2 to 9 wt%, alternatively from 3 to 8 wt%, all based on weight of the curable organosiloxane.

[087] The silicone extender may be an unsubstituted hydrocarbyl-containing MD organosiloxane such as a bis(trihydrocarbyl-terminated) dihydrocarbylorganosiloxane, wherein each hydrocarbyl independently is unsubstituted (Ci -Ci o^M (e.g., methyl), (C2- Ci o)a^|kenyl, (C2-Ci o)a^|kyⁿy^|. benzyl, phenethyl, phenyl, tolyl, or naphthyl. Examples of the silicone extender are polydimethylsiloxanes, including DOW CORNING® 200 Fluids, Dow Corning Corporation, Midland, Michigan, USA. These fluids may have kinematic viscosity ranging from 50 to 100,000 centiStokes (cSt; 50 to 100,000 square millimeters per second (mm²/s)), alternatively 50 to 50,000 cSt (50 to 50,000 mm²/s)„ and alternatively

12,500 to 60,000 cSt (12,500 to 60,000 mm²/s). The kinematic viscosity is measured according to the method described later. In some embodiments the curable silicone and ECSA lack the silicone extender; in other embodiments they further comprise the silicone extender. The concentration of the silicone extender, when present, may be from 0.1 to 10 wt%, alternatively from 0.5 to 5 wt%, alternatively from 1 to 5 wt%, all based on weight of the curable silicone.

[088] The cure inhibitor may be used to delay onset of, inhibit, slow the reaction rate of, or prevent start of the curing reaction. When the curing reaction is a hydrosilylation reaction, the cure inhibitor is a hydrosilylation reaction inhibitor, which inhibits the hydrosilylation reaction of the hydrosilylation-curable organosiloxane as compared to that of the same composition but with the hydrosilylation reaction inhibitor omitted therefrom. Examples of suitable hydrosilylation reaction inhibitors are acetylenic alcohols, silylated acetylenic compounds, cycloalkenylsiloxanes, ene-yne compounds, phosphines, mercaptans, hydrazines, amines, fumarate diesters, and maleate diesters, Examples of the acetylenic alcohols are 1 -propyn-3-ol; 1 -butyn-3-ol; 2-methyl-3-butyn-2-ol; 3-methyl-1 - butyn-3-ol; 3-methyl-1 -pentyn-3-ol; 4-ethyl-1 -octyn-3-ol; 1 -ethynyl-1 -cyclohexanol; 3,5- dimethyl-l-hexyn-3-ol; 4-ethyl-1 -octyn-3-ol; 1 -ethynyl-l-cyclohexanol; 3-phenyl-1 -butyn-3-ol; and 2-phenyl-3-butyn-2-ol. E.g., the hydrosilylation reaction inhibitor may be 1 -ethynyl-1 - cyclohexanol. Examples of cycloalkenylsiloxanes are methylvinylcyclosiloxanes, e.g., 1 ,3,5,7-tetramethyl-1 ,3,5,7-tetravinylcyclotetrasiloxane and 1 ,3,5,7-tetramethyl-1 ,3,5,7- tetrahexenylcyclotetrasiloxane. Examples of ene-yne compounds are 3-methyl-3-penten-l- yne and 3,5-dimethyl-3-hexen-l-yne. An example of phosphines is triphenylphosphine. Examples of fumarate diesters are dialkyl fumarates, dialkenyl fumarates (e.g., diallyl fumarates), and dialkoxyalkyl fumarates. Examples of maleate diesters are dialklyl maleates and diallyl maleates. Examples of silylated acetylenic compounds are (3-methyl- 1 -butyn-3-oxy)trimethylsilane, ((1 ,1 -dimethyl-2-propynyl)oxy)trimethylsilane, bis(3-methyl-1 - butyn-3-oxy)dimethylsilane, bis(3-methyl-1 -butyn-3-oxy)silanemethylvinylsilane, bis((1 ,1 - dimethyl-2-propynyl)oxy)dimethylsilane, methyl(tris(1 ,1 -dimethyl-2-propynyloxy))silane, methyl(tris(3-methyl-1 -butyn-3-oxy))silane, (3-methyl-1 -butyn-3-oxy)dimethylphenylsilane, (3-methyl-1 -butyn-3-oxy)dimethylhexenylsilane, (3-methyl-1 -butyn-3-oxy)triethylsilane, bis(3-methyl-1 -butyn-3-oxy)methyltrifluoropropylsilane, (3,5-dimethyl-1 -hexyn-3- oxy)trimethylsilane, (3-phenyl-1 -butyn-3-oxy)diphenylmethylsilane, (3-phenyl-1 -butyn-3- oxy)dimethylphenylsilane, (3-phenyl-1 -butyn-3-oxy)dimethylvinylsilane, (3-phenyl-1 -butyn- 3-oxy)dimethylhexenylsilane, (cyclohexyl-1 -ethyn-1 -oxy)dimethylhexenylsilane,

(cyclohexyl-1 -ethyn-1 -oxy)dimethylvinylsilane, (cyclohexyl-1 -ethyn-1 - oxy)diphenylmethylsilane, and (cyclohexyl-1 -ethyn-1 -oxy)trimethylsilane. The hydrosilylation reaction inhibitor may be methyl(tris(1 ,1 -dimethyl-2-propynyloxy))silane or ((1 ,1 -dimethyl-2-propynyl)oxy)trimethylsilane. The hydrosilylation reaction inhibitor may be a combination of any two or more of the foregoing examples, either taken from within a single structural class or from at least two different structural classes. In some embodiments the curable silicone and ECSA lack the cure inhibitor; in other embodiments they further comprise the cure inhibitor. The concentration of the cure inhibitor, when present, may be from 0.1 to 5 wt%, alternatively from 0.5 to 2 wt%, all based on weight of the curable silicone.

[089] The defoamer may be used to inhibit or prevent foaming during formation of the curable silicone or the curable organosiloxane. In some embodiments the curable silicone and ECSA lack the defoamer; in other embodiments they further comprise the defoamer.

[090] The biocide may be an antimicrobial compound, antibacterial compound, antiviral compound, fungicide, herbicide, or pesticide. The biocide may be used to inhibit contamination or degradation of the curable silicone or the curable organosiloxane during manufacturing, storage, transportation, or application thereof; and/or inhibit contamination or degradation of the ECSA during curing and or use in the electrical component. In some embodiments the curable silicone and ECSA lack the biocide; in other embodiments they further comprise the biocide.

[091] The chain lengthener may be used to extend lengths of chains of ingredients (A), (B), or (A) and (B) before any coupling or crosslinking occurs during curing of the curable silicone. Examples of suitable chain lengtheners are difunctional silanes (e.g., 1 ,1 ,2,2- tetramethyldisilane) and difunctional siloxanes (e.g., a dimethylhydrogen-terminated polydimethylsiloxane having a degree of polymerization (DP) of from 3 to 50, e.g., from 3 to 10). In some embodiments the curable silicone and ECSA lack the chain lengthener; in other embodiments they further comprise the chain lengthener. The concentration of the chain lengthener, when present, may be from 0.1 to 10 wt%, alternatively from 0.5 to 5 wt%, all based on weight of the curable silicone.

[092] The chain endblocker may be used to terminate a chain and prevent further extending or crosslinking during curing of the curable silicone. The chain endblocker may be an unsubstituted hydrocarbyl-containing siloxane M unit, wherein the hydrocarbyl independently is as described for the hydrocarbyl of the silicone extender. An example of a suitable chain endblocker is an organosiloxane having one or more trimethylsiloxy groups. In some embodiments the curable silicone and ECSA lack the chain endblocker; in other embodiments they further comprise the chain endblocker. The concentration of the chain endblocker, when present, may be from 0.1 to 10 wt%, alternatively from 0.5 to 5 wt%, all based on weight of the curable silicone.

[093] The anti-aging additive may be used to delay onset of, inhibit, decrease rate of, or prevent degradation of the curable silicone and/or ECSA when exposed to degradation- promoting condition(s). Examples of degradation promoting conditions are exposure to oxidant, ultraviolet light, heat, moisture, or a combination of any two or more thereof. Examples of suitable anti-aging additives are antioxidants, UV absorbers, UV stabilizers, heat stabilizers, desiccants, and combinations thereof. Suitable antioxidants include sterically hindered phenols (e.g., vitamin E). Suitable UV absorbers/stabilizers include phenol. Suitable heat stabilizers include iron oxides and carbon blacks. Suitable moisture stabilizers include anhydrous forms of silica, magnesium oxide and calcium oxide. In some embodiments the curable silicone and ECSA lack the anti-aging additive; in other embodiments they further comprise the anti-aging additive. The concentration of the anti- aging additive, when present, may be from 0.01 to 5 wt%, alternatively from 0.1 to 2 wt%, all based on weight of the curable silicone.

[094] In some embodiments the curable silicone is a curable silicone comprising a blend of the following ingredients: An isoalkanes mixture comprising at least three of (Ci 2-C-| 6)isoalkanes and has an initial boiling point of greater than 210° C and an end boiling point of less than 270° C and the hydrocarbon vehicle is at a concentration of from 9 to 1 1 wt% based on weight of the curable silicone; A hydrosilylation-curable polydimethylsiloxane comprising at least one vinyl-functional polydimethylsiloxane compound having on average per molecule at least 1 vinyl moieties, at least one trimethylsiloxy-terminated dimethyl methylhydrogensilicon compound having on average per molecule at least 1 .1 Si-H moieties, a microencapsulated platinum hydrosilylation catalyst, a bis(alpha,omega-glycidoxyalkyl-D3 to D6 alkyl,hydrogencyclosiloxane), and bis(alpha,omega-glycidoxyalkyl)-dialkyl/(alkyl,alkenyl)siloxane adhesion promoter; and wherein the vinyl-functional polydimethylsiloxane compound is from 70 to 78 wt% of the hydrosilylation-curable polydimethylsiloxane, the trimethylsiloxy-terminated dimethyl methylhydrogensilicon compound is from 1 to 8 wt% of the hydrosilylation-curable polydimethylsiloxane, the microencapsulated hydrosilylation catalyst is from 10 to 15 wt% of the hydrosilylation-curable polydimethylsiloxane, the bis(alpha,omega-glycidoxyalkyl-D3 to D6 alkyl,hydrogencyclosiloxane) is from 0 to 7 wt% of the hydrosilylation-curable polydimethylsiloxane, and the bis(alpha,omega-glycidoxyalkyl)- dialkyl/(alkyl,alkenyl)siloxane adhesion promoter is from 0 to 10 wt% of the curable polydimethylsiloxane; and wherein together the trimethylsiloxy-terminated dimethyl methylhydrogensilicon compound, microencapsulated hydrosilylation catalyst, bis(alpha,omega-glycidoxyalkyl-D3 to D6 alkyl,hydrogencyclosiloxane), and the bis(alpha,omega-glycidoxyalkyl)-dialkyl/(alkyl,alkenyl)siloxane adhesion promoter are from 20 to 30 wt% of the curable organosiloxane; and Electrically conductive filler consisting essentially of a combination of a silver filler and an enhancing filler lacking silver, copper, gold, and aluminum ; and Wherein the silver filler is silver particles at a concentration of from 19.5 to 25 wt% and total silver concentration is from 19.5 to 25 wt% based on weight of the curable polydimethylsiloxane; and Wherein the enhancing filler is a combination of tin particles and multi-walled carbon nanotubes wherein the multi-walled carbon nanotubes are at a concentration of from 0.7 to 0.94 wt% and the tin particles are at a concentration of from 56 to 64 wt%, all based on weight of the curable silicone. The curable silicone may be characterizable by a volume resistivity of less than 0.00090 Ω-cm.

[095] Alternatively, the vinyl-functional polydimethylsiloxane compound may be from 70 to 75 wt% of the hydrosilylation-curable polydimethylsiloxane; the trimethylsiloxy-terminated dimethyl methylhydrogensilicon compound may be from 1 to 5 wt% of the hydrosilylation- curable polydimethylsiloxane; the microencapsulated hydrosilylation catalyst may be from 10 to 15 wt% of the hydrosilylation-curable polydimethylsiloxane; the bis(alpha,omega- glycidoxyalkyl-D3 to D6 alkyl,hydrogencyclosiloxane) may be from 0 to 7 wt% (e.g., 0 wt%), alternatively from 0.1 to 7 wt% of the hydrosilylation-curable polydimethylsiloxane, and the bis(alpha,omega-glycidoxyalkyl)-dialkyl/(alkyl,alkenyl)siloxane adhesion promoter may be from 0.1 to 10 wt%, alternatively from 1 to 10 wt%, of the hydrosilylation-curable polydimethylsiloxane. Prior to its use to prepare the curable silicone, the hydrosilylation- curable polydimethylsiloxane may lack the hydrocarbon vehicle, silver particles, and enhancing filler lacking silver. As for concentrations of the ingredients in terms of wt% of the curable silicone prepared with the hydrosilylation-curable polydimethylsiloxane, the vinyl-functional polydimethylsiloxane compound may be from 16 to 18 wt% (e.g., 17 wt%) of the curable silicone, the trimethylsiloxy-terminated dimethyl methylhydrogensilicon compound may be from 0.1 to 2 wt% (e.g., 1 wt%) of the curable silicone, the microencapsulated hydrosilylation catalyst may be from 2 to 5 wt% (e.g., 3 wt%) of the curable silicone, and the bis(alpha,omega-glycidoxyalkyl)-dialkyl/(alkyl,alkenyl)siloxane adhesion promoter may be from 1 to 4 wt% (e.g., 2 wt%) of the curable silicone . In such an embodiment of the curable silicone, the concentration of the hydrocarbon vehicle may be from 7 to 19 wt% of the curable silicone, the silver particles may be silver flakes and may be at a concentration of from 19.5 to 25 wt% of the curable silicone, and the enhancing filler is a combination of tin particles and multi-walled carbon nanotubes wherein the multi-walled carbon nanotubes are at a concentration of from 0.7 to 0.94 wt% and the tin particles are at a concentration of from 56 to 64 wt%, all of the curable silicone. In such an embodiment, the total concentration of silver may be from 19.5 to 25 wt% of the curable silicone. When the curable silicone also contains the bis(alpha,omega-glycidoxyalkyl-D3 to D6 alkyl,hydrogencyclosiloxane), the concentration of the bis(alpha,omega-glycidoxyalkyl- D3 to D6 alkyl,hydrogencyclosiloxane) may be from 0.5 to 1 .5 wt% (e.g., 1 wt%) of the curable silicone.

[096] The concentration of SiH-containing ingredients may be adjusted in the curable silicone such that the total SiH concentration in the curable silicone may be reached with different proportions of the SiH-containing ingredients. For example, when the curable silicone also contains the bis(alpha,omega-glycidoxyalkyl-D3 to D6 alkyl,hydrogencyclosiloxane), the concentration of the trimethylsiloxy-terminated dimethyl methylhydrogensilicon compound may be from 0.2 to 0.9 wt% (e.g., 0.5 wt%) and the concentration of the bis(alpha,omega-glycidoxyalkyl-D3 to D6 alkyl,hydrogencyclosiloxane) may be from 0.5 to 1 .5 wt% (e.g., 1 wt%), both based on weight of the curable silicone. When the curable silicone lacks (i.e., 0 wt%) the bis(alpha,omega-glycidoxyalkyl-D3 to D6 alkyl,hydrogencyclosiloxane), the concentration of the trimethylsiloxy-terminated dimethyl methylhydrogensilicon compound may be from 0.2 to 1 .5, alternatively from 0.9 to 1 .5 wt% based on weight of the curable silicone.

[097] It is generally known in the art how to prepare curable silicones comprising multiple ingredients including fillers. For example, the curable silicone and curable organosiloxane may be prepared by a method comprising combining the ingredients such as by mixing. The ingredients may be combined in any order, simultaneously, or any combination thereof unless otherwise noted herein. Typically mechanics of the combining comprises contacting and mixing ingredients with equipment suitable for the mixing. The equipment is not specifically restricted and may be, e.g., agitated batch kettles for relatively high flowability (low dynamic viscosity) compositions, a ribbon blender, solution blender, co-kneader, twin- rotor mixer, Banbury-type mixer, mill, or extruder. The method may employ continuous compounding equipment, e.g., extruders such as twin screw extruders (e.g., Baker Perkins sigma blade mixer or high shear Turello mixer), may be used for preparing compositions containing relatively high amounts of particulates. The curable silicone and curable organosiloxane may be prepared in batch, semi-batch, semi-continuous, or continuous process. General methods are known, e.g., US 2009/0291238; US 2008/0300358.

[098] The curable silicone and curable organosiloxane may be prepared as a one-part or multiple-part composition. The one-part composition may be prepared by combining all ingredients by any convenient means, such as mixing, e.g., as described for the method. All mixing steps or just a final mixing step may be performed under conditions that minimize or avoid heating (e.g., maintain temperature below 30 ° C during mixing). The multiple-part (e.g., 2 part) composition may be prepared where at least a primary organosiloxane (e.g., the diorganosiloxane such as ingredient (A)), and optionally any other organosilicon compound (e.g., an adhesion promoter and/or chain extender/crosslinker such as the organohydrogensilicon compound of ingredient (B)), is stored in one part, and any catalyst (e.g., ingredient (C)) is stored in a separate part, and the parts are combined (e.g., by mixing) shortly before use of the composition. Alternatively, the primary organosiloxane and any catalyst may be stored in one part and any other organosilicon compound may be stored in a separate part. Typically the chain extender/crosslinker and the catalyst are stored in separate parts when the catalyst is catalytically active (not microencapsulated or not inhibited). A master batch containing the primary organosiloxane may be prepared and stored until ready for dilution to prepare the one part. An illustrative preparation is described later in the examples.

[099] The carbon nanotubes may be mixed with at least a portion of the curable organosiloxane to form a master batch comprising a dispersion of the carbon nanotubes and at least the portion of the curable organosiloxane. The dispersing of the carbon nanotubes into the portion of the curable organosiloxane to prepare the master batch may be carried out by any suitable mixing means. Examples of suitable mixing means are ultrasonication, dispersion mixing, planetary mixing, and three roll milling. Alternatively or additionally, surfactants may be used to facilitate dispersion of the carbon nanotubes in a carrier liquid (e.g., water) to form an emulsion, which may be mixed with the curable organosiloxane to give a temporary mixture, and then the carrier liquid (e.g., water) may be removed from the temporary mixture to give the master batch. For convenience, the carrier liquid may have having a boiling point from 20° to 150° C. When a surfactant is used, the carrier liquid typically is water or an aqueous mixture, but the carrier liquid may be nonaqueous such as methanol or a polydimethylsiloxane fluid having a boiling point from 20° to 150° C. Once formed the master batch may then be mixed with the other ingredients of the curable silicone, including any remaining portion of the curable organosiloxane, to prepare the curable silicone.

[0100] Once prepared the curable silicone and curable organosiloxane may be used immediately or stored for any practical period, e.g., > 1 hour, alternatively > 1 day, alternatively > 1 week, alternatively > 30 days, alternatively > 300 days, alternatively > 2 years before use. The curable silicone and curable organosiloxane may be stored in a container that protects the curable silicone or curable organosiloxane from exposure to curing conditions (e.g., heat or moisture). The storage may be at a suitable temperature (e.g., -40° < 20° C, e.g., -30° C) and, if desired, under an inert gas atmosphere (e.g., N₂ or

Ar gas). When desired, curing of the curable silicone may be initiated by exposing it to the curing conditions to give the ECSA.

[0101] The curable silicone may be characterized by the characteristics of the ECSA prepared therefrom. For example, the curable silicone may be characterizable by a volume resistivity, electrically conductivity, flexibility, or any combination thereof of the ECSA.

[0102] The electrically conductive silicone adhesive (ECSA). The ECSA may comprise a binder matrix comprising any cured silicone such as a condensation cured organosiloxane, free radical cured organosiloxane, or hydrosilylation cured organosiloxane. Some embodiments of the present invention provide the ECSA as a composition of matter, which may be described as a product-by-process. Other embodiments provide the ECSA as a composite structure comprising the silver filler and enhancing filler widely dispersed throughout a binder matrix (cured organosiloxane matrix) comprising a product of curing the curable silicone. The as-cured ECSA facilitate transmission of electric current as is, e.g., such that an as-cured ECSA disposed between first and second electrical components of an electrical device facilitates conduction of electric current between the first and second electrical components via the as-cured ECSA without having to expose the electrically conductive filler in the as-cured ECSA. The composite structure of the ECSA may be characterizable by a cross-sectional image, longitudinal image, or two- or three- dimensional arrangement of the silver filler and enhancing filler in the binder matrix. Any carbon nanotubes may require higher magnification viewing to be seen in the cross- sectional image compared to any magnification that may be used to view the silver particles, Ag-coated core particles, and/or cured organosiloxane matrix. The ECSA may be characterized by a volume resistivity of less than 0.003 Ω-cm, or any one of the aforementioned volume resistivity ranges described before. The ECSA may be characterizable by a volume resistivity less than 0.003 Ω-cm, alternatively < 0.00200 Ω-cm, alternatively < 0.00100 Ω-cm, alternatively < 0.00090 Ω-cm, alternatively < 0.00080 Ω-cm, alternatively < 0.00060 Ω-cm. The volume resistivity of the curable silicone is > 0 Ω-cm. Unless indicated otherwise herein, all volume resistivity values are measured according to Volume Resistivity Test Method, described later.

[0103] The ECSA may provide adhesion to a variety of different substrates such as a metal (e.g., aluminum), a ceramic, or a silica glass substrate. In some embodiments, surfaces of some substrates may be treated first to remove or change composition of a surface layer, which may be of a different material than a basal layer of the substrate. Alternatively, the same surface layer may be untreated or mechanically patterned before being contacted with the curable silicone and/or ECSA. Examples of surface layers that might be removed, alternatively left on, are metal oxide layers, protective coatings (e.g., organic coatings applied to metals that are prone to oxidation when exposed to ambient air), and powders such as powder residues that may have been deposited on the substrate be mechanical etching of the substrate. Examples of metal substrates are the electrically conductive metals and metal alloys described before, alternatively aluminum, copper, gold, niobium, palladium, platinum, silver, stainless steels, tantalum, and titanium. The surface layer of the substrate receiving the curable silicone or ECSA is a material that is capable of chemically bonding to the ECSA, which after being prepared by curing the curable silicone thereon is adhered to the material such that the adhesive strength is achieved. The ECSA may also provide adhesion to a variety of different organic polymer substrates that have first been primed or treated. Examples of organic polymer substrates that may be primed or treated to form a surface thereon for adhering to the ECSA are polyethylene and polypropylene. If the surface layer is treated (primed), the priming or treating the surface of the substrate may comprise treating a working portion of the surface thereof with an adhesion promoter or by chemical etching, mechanical etching, or plasma treating the working portion of the surface. Examples of suitable adhesion promoters are OFS 6040 XIAMETER, DOW CORNING P5200 Adhesion Promoter, and 1200 OS Primer Clear. Generally, increasing curing temperature and/or curing time will improve adhesion. [0104] Different embodiments of the ECSA may be compared by characterizing their adhesive strength on a same substrate material such as a particular silica glass substrate according to the Peel Resistance Test Method described later. When the substrate material is an unprimed or untreated substrate, alternatively a substrate that has been previously primed or treated, the ECSA may be characterizable by an adhesive strength of at least 0.3 Newton (N) when measured on silica glass substrate according to the Peel Resistance Test Method. Alternatively, the ECSA may be characterizable by an adhesive strength of at least 0.1 N, alternatively at least 0.3 N, alternatively at least 0.5 N, alternatively at least 1 .0 N. The ECSA may have any maximum adhesive strength. In some embodiments the ECSA may have a maximum adhesive strength of 5 N, alternatively 2 N, alternatively 1 N, alternatively 0.3 N. The adhesive strength value of a particular ECSA may vary depending on the material of the substrate. For purposes of characterizing an embodiment of the curable silicone after curing as being an ECSA, the substrate may be borosilicate silica glass. Different ECSAs may be characterized or compared by their adhesive strength according to the Peel Resistance Test Method when measured on a same substrate such as the borosilicate silica glass substrate. The silica glass may be Eagle XG silica glass (e.g., HS-20/40) from Corning Inc., Corning, New York, USA.

[0105] The ECSA independently may be employed in some applications as an adhesive but not as a means for conducting electrical current, such applications including using the ECSA for adhering same or different substrates comprising non-electrically conductive materials to each other. Reiterated, the use of the ECSA as an adhesive may include applications wherein the ECSA does not function or need to function to conduct electric current. Alternatively, the ECSA may be used in some applications as an adhesive and, at least periodically, as a means for conducting electric current between at least two electrical components of an electrical device. The at least two electrical components have opposing surfaces between which contact the ECSA. The periods during which the electric current may be conducted therebetween are when the electrical components or electrical components and electrical device are electrically active. Alternatively, the ECSA may be employed in some applications as a means for conducting electric current between at least two electrical components of an electrical device, but not as an adhesive for adhering the electrical components to each other. Reiterated, the use of the ECSA as a means for conducting electric current may between at least two electrical components of an electrical device may include applications where the electrical components are being held in electrical operative contact to the ECSA via a means other than adhesive action. Examples of such other non-adhesive means are where the electrical components are disposed in friction fit with each other or a common housing, a mechanical fastening means such as an externally screw-threaded fastener, solder (limited to contact with a very minor areas of the opposing surfaces of the electrical components), and a clamp.

[0106] The theoretical total concentration of silver in the ECSA, assuming complete removal of the hydrocarbon vehicle during curing of the curable silicone to give the ECSA, may be calculated as described later. In some embodiments the theoretical total concentration of silver in the ECSA is from 22 to 49 wt%, alternatively from 23 to 50.0 wt%, alternatively from 25.0 to 39 wt%.

[0107] An electrical device comprising first and second electrical components having opposing surfaces and the ECSA disposed between and in adhering operative contact with the opposing surfaces of the first and second electrical components; wherein the first and second electrical components are disposed for electrical operative communication with each other via the ECSA; and wherein the ECSA is characterizable by a volume resistivity of less than 0.0010 Ω-cm, or any one of the aforementioned volume resistivity ranges described before. The ECSA binds the electrical components together and facilitates transfer of electric current between them via the ECSA during operation of the electrical device. A wide variety of electrical devices may employ the ECSA. The opposing surfaces of the first and second electrical components may be surfaces of an untreated substrate as described above. Alternatively, one or both of the opposing surfaces of the first and second electrical components may be surfaces of substrates that may have previously been primed or treated to form a surface thereon for adhering to the ECSA. Examples of electrical devices that may be manufactured with the curable silicone and ECSA are electrical components such as antenna, attenuators, light ballast, batteries, bimetallic strips, brushes, capacitors, electrochemical cells, control boards, instrument panels, distributors, electrographs, electrostatic generators, electronic filters, light flashers, fuses, inductors, jacks, plugs, electrostatic precipitators, rectifiers, relays, resistors, spark arrestors, suppressors, terminals, and electronics circuit board wiring patterns. Examples of such electrical devices also include higher order electrical devices, which may contain a plurality of such electrical components. The higher order electrical devices include photovoltaic cell modules and panels, and electronic devices such as computers, tablets, routers, servers, telephones, and smartphones. The use of the ECSA in the electrical devices is not particularly limited, and for example the ECSA may be used in place of any ECA of ad rem prior art electrical device.

[0108] A method of manufacturing the electrical device comprising the first and second electrical components having surfaces and the ECSA, the method comprising depositing the curable silicone onto one or both surfaces of the first and second electrical components, and orienting the first and second electrical components so that their surfaces are opposing each other to give a preassembly comprising the curable silicone disposed between and in physical contact with the opposing surfaces of the first and second electrical components; and curing the curable silicone between the opposing surfaces of the first and second electrical components to give the electrical device. The depositing may be performed in any suitable manner. E.g., a suitable manner of the depositing comprises disposing all of the curable silicone on a surface of one, but not both, of the first and second electrical components, and then bringing the disposed curable silicone in opposing contact to the surface of the other one (i.e., the one lacking the composition) of the first and second electrical components to give the preassembly. Another suitable manner of the depositing comprises disposing a first portion of the curable silicone on one of the surfaces of the first and second electrical components, disposing a second portion of the curable silicone on the other one of the surfaces of the first and second electrical components, and then bringing the first and second portions of the disposed curable silicone in opposing contact to give the preassembly. The first and second portions of the curable silicone may be the same or different in amount, composition, batch, age, extent of curing, and/or other property (e.g., temperature). The invention contemplates that still other suitable manners may be used so long as the preassembly is produced therewith. It is generally known in the art how to prepare different electrical component assemblies comprising an ECSA prepared by curing a curable silicone. The electrical device comprises the first and second electrical components and the electrically conductive silicone adhesive disposed between and in adhering operative contact with the opposing surfaces of the first and second electrical components such that the first and second electrical components are disposed for electrical operative communication with each other via the electrically conductive silicone adhesive. The ECSA in the electrical device is characterizable by a volume resistivity of less than 0.0030 Ω-cm measured according to Volume Resistivity Test Method. The manufacturing method may comprise manufacturing more than one electrical device wherein curable silicones having different rheologies are employed for manufacturing different ones of the electrical devices. For example, the method may comprise depositing a first curable silicone having a first thixotropic lndex(n.-|/n.i o) ^{onto tne} opposing surfaces of the first and second electrical components to give a first preassembly comprising the first curable silicone disposed between and in physical contact with the opposing surfaces of the first and second electrical components; and curing the first curable silicone between the opposing surfaces of the first and second electrical components to give a first electrical device; adjusting the rheology of the first curable silicone to give a second curable silicone having a second thixotropic lndex(n.-|/n.io). wherein the first thixotropic lndex(n.-|/n.io) ^ancl second thixotropic lndex(n.-|/n.io) differ from each other by at least 0.3, alternatively at least 0.5, alternatively at least 1 , alternatively at least 2, alternatively at least 3, alternatively at least 4, alternatively at least 5, all as a result of the adjusting; and depositing the second curable silicone onto opposing surfaces of third and fourth electrical components to give a second preassembly comprising the second curable silicone disposed between and in physical contact with the opposing surfaces of the third and fourth electrical components; and curing the second curable silicone between the opposing surfaces of the third and fourth electrical components to give a second electrical device. Each depositing step may independently be performed in any suitable manner as described before to independently give the first and second preassemblies. A portion of a master batch of the first curable silicone may be used in the manufacture of the first electrical device and another portion of the master batch of the first curable silicone may be used in the adjusting step. The first electrical device may be manufactured before, alternatively after the adjusting step. Each of the first and second thixotropic lndex(n.-|/n.i o) values independently may be between 3 and 10. The first and second electrical components of the first electrical device are disposed for electrical operative communication with each other via a first ECSA, wherein the first ECSA is prepared by the curing of the first curable silicone and is characterizable by a volume resistivity of less than 0.0030 Ω-cm. The third and fourth electrical components of the second electrical device are disposed for electrical operative communication with each other via a second ECSA, wherein the second ECSA is prepared by the curing of the second curable silicone and is characterizable by a volume resistivity of less than 0.0030 Ω-cm. The volume resistivity of the first and second ECSAs may be the same, alternatively may differ from each other by less than 0.0001 Ω-cm, alternatively less than 0.00005 Ω-cm, alternatively less than 0.00002 Ω-cm.

[0109] The manufacturing method may comprise manufacturing more than one electrical device wherein the depositing and/or curing conditions (collectively, manufacturing conditions) are different. For example, the depositing and/or curing conditions may be different from each other in at least one of temperature of the curable silicone, rate of flow of the curable silicone, cure time of the curable silicone, orientation of the substrate when in contact with the curable silicone, and chemical composition or structure of the surfaces of the first and second substrates. The rheology may be adjusted without increasing the total concentration of electrically conductive core such that the thixotropic index(n.-|/n.i o) values before and after the rheology adjustment are each between 3 and 10 and differ from each other by at least 0.3, alternatively at least 0.5, alternatively at least 1 , alternatively at least 2, alternatively at least 3, alternatively at least 4, alternatively at least 5, all as a result of the adjusting.

[0110] As mentioned before, in any of the foregoing embodiments, depositing the curable silicone onto the opposing surfaces of the first and second electrical components may comprise contacting the curable silicone to one or both surfaces, and bringing the surfaces into opposition to each other so that the curable silicone directly contacts both of the opposing surfaces. Likewise in any of the foregoing embodiments employing same, the depositing the curable silicone onto the opposing surfaces of the third and fourth electrical components may comprise contacting the curable silicone to one or both surfaces, and bringing the surfaces into opposition to each other so that the curable silicone directly contacts both of the opposing surfaces. The contacting of the curable silicone to the surfaces may be done sequentially or simultaneously. In the electrical device the first and second electrical components sandwich the curable silicone between their opposing surfaces.

[0111] The curable silicone may be applied to the surface(s) by various methods of deposition. Examples of suitable methods include printing through screen or stencil, dispensing, or other methods such as aerosol, ink jet, gravure, or flexographic, printing.

The curable silicone may be applied to the surfaces to make direct physical, adhesive and electrical contact to the first and second electrical components, alternatively the third and fourth electrical components. Curing the applied curable silicone gives the ECSA in direct physical, adhesive and electrical contact to the opposing faces, and enables electrical operative communication between the first and second electrical components, alternatively the third and fourth electrical components, via the ECSA.

[0112] Conditions for curing typically comprise elevated temperature leading to the substantial removal of the hydrocarbon vehicle. Substantially all of other ingredients of the curable silicone are, or react in situ to form components that are, less volatile under the curing conditions than is the hydrocarbon vehicle. Thus, the concentration of silver and other ingredients besides the hydrocarbon vehicle are usually higher in the ECSA than in the curable silicone. If the concentration of hydrocarbon vehicle is X wt% and total concentration of silver is Y1 wt% in the curable silicone, and assuming complete removal (100% removal) of the hydrocarbon vehicle, then theoretically the total concentration of silver in the ECSA would equal Y2 wt% = 100 x [Y1 wt%/(100 wt% - X wt%)]. As described, Y1 is from 19.5 to 43 wt% and X is from 7.0 to 20 wt%, all based on total weight of the curable silicone. Therefore, the theoretical total concentration of silver in the ECSA, assuming complete removal of the hydrocarbon vehicle during curing of the curable silicone to give the ECSA, may be up to < 54 wt% (43 wt% total silver concentration in curable silicone having 20 wt% hydrocarbon vehicle gives ECSA with 43/0.80 = 53.8 wt% Ag). In some embodiments, the total silver concentration in the ECSA may be < 45 wt%, alternatively < 40 wt%, alternatively < 30 wt%, alternatively < 25 wt%. The total silver concentration in the ECSA may be at least 21 .1 wt%, alternatively > 21 .5 wt%, alternatively > 22.0 wt%, alternatively > 24.0 wt%.

[0113] Depending on whether the curable organosiloxane is condensation curable, free radical curable or hydrosilylation curable as described earlier, conditions for the curing may further comprise exposure of the curable silicone to UV light, peroxides, metal-containing catalyst, and/or moisture. For example, curing the hydrosilylation-curable silicone typically comprises heating the hydrosilylation-curable organosiloxane containing the hydrosilylation catalyst to remove a substantial amount of the hydrocarbon vehicle and give the ECSA. The curing conditions may facilitate shrinkage of volume of material during curing and result in improved packing of the electrically conductive filler and an ECSA with increased electrical conductivity, decreased volume resistivity, or both compared to an ECSA that is the same except having a hydrocarbon vehicle with a boiling point below 100 ° C (e.g., 50° C). In the curable silicone and ECSA, all of the electrically conductive filler, e.g., electrically conductive metal particles, including Ag particles, Ag-coated core particles, and metal particles of the enhancing filler, may be unsintered.

[0114] Some advantages and benefits of the present invention. In the present invention, the carbon nanotubes are believed to have minimal or no negative effect on electrical conductivity. While carbon nanotubes generally may impart some electrical conductivity in a cured polymer that would otherwise not be electrically conductive if it lacked carbon nanotubes, instead the present invention advantageously may employ the carbon nanotubes as a concentration-sensitive rheology modifier in the curable silicone at concentrations where the carbon nanotubes ultimately have no or minimal negative effect on electrical conductivity of the ECSA resulting from curing the curable silicone. The present invention provides the curable precursor composition wherein total concentration of silver in the composition is significantly below 45 wt% and while the volume resistivity of the resulting ECA can be maintained below 0.003 Ω-cm. The present invention advantageously found a way to successfully employ certain secondary filler that functions in an enhancing manner in the present curable silicone and ECSA without adding other highly electrically conductive metal such as gold or copper metals, alternatively gold, copper, or aluminum metals, to the curable silicone and ECSA. This has enabled lowering the total concentration of silver in a silicone binder matrix to less than 45 wt% (19.5 to 43 wt%) while still achieving a volume resistivity of the curable silicone less than 0.0030 Ω-cm, alternatively < 0.0020 Ω-cm, alternatively < 0.0010 Ω-cm, alternatively < 0.00090 Ω-cm, alternatively < 0.00080 Ω-cm, alternatively < 0.00060 Ω-cm, without adding other highly electrically conductive metal filler.

[0115] Alternatively or additionally, as mentioned before the curable silicone may be curable at a temperature less than or equal to 160° C. This cure temperature is less than temperatures required for sintering the metal particles and less than temperatures required for soldering conductive compositions based on mixtures of electrically conductive and solderable particles.

[0116] Alternatively or additionally, the curable silicone has sufficient flexibility for end-use application requiring low stress interconnections. The curable silicone and ECSA enhances durability of embodiments of the electrical device and electronic devices that are exposed to wide temperature variations

[0117] Alternatively or additionally, in some embodiments wherein the enhancing filler of the curable silicone contains carbon nanotubes, the curable silicone may advantageously characterizable by a thixotropic index that is adjustable from 3 to 10 (3.0 to 10.0) without increasing the total concentration of silver, and while the curable silicone remains curable to an ECSA having a volume resistivity of less than 0.003 Ω-cm and the total concentration of silver in the curable silicone is from 19.5 to 43 wt% and the curable silicone lacks gold and copper metals, alternatively, copper, gold, and aluminum metals. In such embodiments the rheology of the curable silicone may be adjusted over a wide range to accommodate different application requirements for making electrical devices while the volume resistivity of the resulting ECSA may be maintained below 0.003 Ω-cm. The manner of adjusting of the thixotropic index may comprise adjusting the combined wt% portion of the silver and carbon nanotubes; alternatively raising or lowering the concentration of carbon nanotubes in the curable silicone so long as the concentration remains within the wt% range described herein for the carbon nanotubes therein, alternatively raising or lowering the concentration of the hydrocarbon vehicle so long as the concentration of the hydrocarbon vehicle remains within the wt% range described herein for the hydrocarbon vehicle, or a combination of two, alternatively three thereof. Such manners of adjusting are contemplated so long as the thixotropic index changes by at least 0.3, alternatively at least 0.5, alternatively at least 1 , alternatively at least 2, alternatively at least 3, alternatively at least 4, alternatively at least 5, all as a result of the adjusting, while the thixotropic index remains greater than 3, the total concentration of the electrically conductive filler does not increase, and the curable silicone remains curable to an ECSA having a volume resistivity of less than 0.003 Ω-cm, alternatively < 0.00200 Ω-cm, alternatively < 0.00100 Ω-cm, alternatively < 0.00090 Ω-cm, alternatively < 0.00080 Ω-cm, alternatively < 0.00060 Ω-cm. Even when the concentration of carbon nanotubes is raised or lowered, the thixotropic index of the ECSA prepared from the curable silicone may change by a significant amount (e.g., 1 or more) while unexpectedly the volume resistivity of the resulting ECSA may remain virtually unchanged (e.g., may change by from 0 to 0.0001 , alternatively from 0 to 0.0005, alternatively from 0 to 0.00002 Ω-cm). Further, while the thixotropic index may be adjusted in this range, the volume resistivity of the resulting ECSA may remain virtually unchanged. Further, the present invention may achieve this advantage without using copper and gold, or copper, gold and aluminum. Therefore, in some embodiments, the curable silicone and ECSA composition lack copper and gold, or copper, gold, and aluminum. Alternatively, the adjusting may be achieved without varying concentration of the hydrocarbon vehicle in the curable silicone, alternatively the concentration of the hydrocarbon vehicle in the curable silicone may be varied by itself or in combination with varying the electrically conductive filler.

[0118] Such an adjustable curable silicone is useful for developing different curable precursor formulations that meet the varied rheology needs of electrical component/device manufacturing conditions while retaining the ECSA electrical properties needed by end- users of the electrical component/device device. For example, the curable silicone has rheology characteristics that are useful for screen printing thereof, including for screen printing different types of electrical components/devices. The curable silicone has sufficient viscosity such that it does not exhibit too much slump, bleeding, dripping, and/or filler settling during screen printing thereof. Additionally, the curable silicone may not have too much viscosity for successful screen printing. The curable silicone has adjustable rheology in order to meet the diverse needs of manufacturers of different electrical devices such as photovoltaic devices and electronic circuit boards while retaining the resulting ECA's electrical properties needed by the device users.

[0119] Alternatively or additionally, the curable silicone has sufficient flexibility for end-use application requiring low stress interconnections. The curable silicone and ECSA enhances durability of embodiments of the electrical devices, which include electronic devices that are exposed to wide temperature variations.

[0120] Determining numerical property values: for purposes of the present invention and unless indicated otherwise, the numerical property values used herein may be determined by the following procedures.

[0121] Determining adhesive strength: for purposes of the present invention and unless indicated otherwise, a Peel Resistance Test Method that is in agreement with the test method described in ASTM D6862-04 (Standard Test Method for 90 Degree Peel Resistance of Adhesives) has been used. Peel Resistance Test Method: uses a 90-degree peel test to determine the resistance-to-peei strength of a test adhesive bonding a rigid adherent (substrate such as silica glass) and a flexible adherent (e.g., 2 mm wide Cu wire). For purposes of this test method, surfaces of the adherents do not undergo surface priming or treatment prior to adhesive application thereto. Test adhesive is screen printed onto the rigid adherent through apertures of dimension 0.5 mm x 1 14 mm x 0.25 mm. Flexible 2 mm wide Cu wire is placed on top of the screen printed test adhesive, and the resulting structure is heat treated at 150°C for 15 minutes in air environment to give a test sample. The 90-degree peel resistance measurement takes place on a gripping fixture of an INSTRON electromechanical testing system, which gripping fixture allows a constant 90 degree peel angle to be maintained during the test. The test sample is positioned on the INSTRON table, and clamped down on both sides of the test area at a distance of approx 5 mm to minimize flexure. About 3 centimeter (cm) length of the Cu wire is standing out of the measurement zone (i.e., test area where the Cu wire contacts the rigid adherent) and is used for attaching the test sample to a pull tester. For every measurement the Cu wire is bent at a 2 mm distance from the measurement zone and inserted into the gripping fixture. Either an end portion of the Cu wire overhangs the rigid adherent, or the end portion is pulled up by hand from the rigid adherent to debond (physically separate) the end portion of the Cu wire from the rigid adherent without debonding all of the Cu wire therefrom, and the debonded end portion is disposed into the gripping fixture. The force needed to bend the Cu wire is not taken into account since only data obtained with the same type of Cu wire are compared. A 100 Newton (N; equivalent to 20 lbs) load cell and a strain rate of 0.5 inch per minute (1 .27 cm/minute) is used and the average peel force over a 15 mm length of travel of the test sample is measured. At least 4 specimens are measured for each test sample to obtain an average peel force, which is what is reported.

[0122] Determining boiling point: measure boiling point by distillation at standard atmospheric pressure of 101 .3 kilopascals (kPa). [0123] Determining dynamic viscosity: for purposes of the present invention and unless indicated otherwise, use dynamic viscosity that is measured at 25° C using a rotational viscometer such as a Brookfield Synchro-lectric viscometer or a Wells-Brookfield Cone/Plate viscometer. The results are generally reported in centipoise. This method is based on according to ASTM D1084-08 (Standard Test Methods for Viscosity of Adhesives) Method B for cup/spindle and ASTM D4287-00(2010) (Standard Test Method for High-Shear Viscosity Using a Cone/Plate Viscometer) for cone/plate. Dynamic viscosity for purposes of determining thixotropic index is measured according to the Tl Test Method described later.

[0124] Determining kinematic viscosity: use test method ASTM-D445-1 1 a (Standard Test Method for Kinematic Viscosity of Transparent and Opaque Liquids (and Calculation of

Dynamic Viscosity)) at 25° C. Expressed in cSt or mm²/s units.

[0125] Determining state of matter: Characterize state of matter as solid, liquid, or gas/vapor at 20⁰ C and a pressure of 101 .3 kPa.

[0126] Determining volume resistivity: The volume resistivity of ECSA test samples reported in the Examples below was determined using the following Volume Resistivity Test Method. The volume resistivity was determined using a four-point-probe instrument, GP 4-TEST Pro, from GP Solar GmbH, Germany. This instrument has a line resistance probe head and incorporates Precise Keithley electronics for current sourcing and voltage measurement. The line resistance probe head is constructed to measure electrical resistance through a 5 cm distance along a conductive strip the ECSA test sample. An aliquot of the test material was deposited on non-conductive substrate (e.g., silica glass or ceramic) by screen printing through apertures of dimension 5 mm x 60 mm x 0.25 mm. This formed a uniform line having an area of 5 mm x 60 mm = 300 mm². The spread test material was thermally cured by conveying it through an oven set to a temperature of 150° C under ambient (air) atmosphere for 15 minutes to produce a test sample of the material (e.g., ECSA The voltage drop between the two inner probe tips was then measured at a selected current to provide a resistance value in Ohms (Ω).

[0127] The initial volume resistivity of the cured composition was calculated using the equation p=R(WxT/L) where p is volume resistivity in Ω-cm, R is resistance Ω of the cured composition measured between two inner probe tips spaced 5 cm apart, W is the width of the cured layer in cm, T is the thickness of the cured layer in cm, and L is the length of the cured layer between the inner probes in cm. The thickness of the cured layer was determined using a micrometer (Ono Sokki digital indicator number EG- 225). If desired, a cross sectional area might be determined more accurately using a Zygo 7300 white light interferometer. Even so, all of the thickness measurements in the below examples were determined with the micrometer. Volume resistivity (p) in Ω-cm units represents the average value of three measurements each performed on identically prepared test specimens. These measurements have a relative error of less than 10 percent.

[0128] Determining thixotropic index(n.-|/n.io)^{: Tne} thixotropic index(n.-|/n.io) ^is determined using the following Tl Test Method. Measure dynamic viscosity (η) in Pascal-seconds (Pa.s) at 25° C using an ARES G2 Parallel Plate Rheometer with 40 millimeter diameter plates and a gap of 1 millimeter (Rheometer). Agitate a test sample for 20 seconds at 1 ,200 revolutions per minute (rpm) with a SPEEDMIXER dual asymmetric centrifugal laboratory mixer (model no. DAC 150 FVZ-K, Haushild & Co. KG, Hamm, Germany). Then immediately load the agitated test sample into the Rheometer for a conditioning step and then a flow sweep step. During the conditioning step, mix the test sample for 300 seconds at a shear rate of 0.001 radians per second to give a conditioned test material. Then during the flow sweep step, measure dynamic viscosity of the conditioned test material at shear rates ranging from 0.001 to 100 radians per second (rad-s^-1 or rad/s), recording at least five data points per shear rate decade (i.e., record at least five data points at 0.001 rad/s, at least five data points at 0.01 rad/s, etc. up to and including at least five data points at 100 rad/s). The thixotropic index(n.-|/n.i o) ^is calculated by dividing the dynamic viscosity values in Pa-s at shear rates of 1 and 10 rad/s, respectively

[0129] Determining weight percent (wt%): base weight percent of an ingredient of a composition, mixture, or the like on weights of ingredients added to prepare, and total weight of, the composition, mixture, or the like.

[0130] Ingredients used in the examples follow.

[0131] Hydrocarbon vehicle (HV1 ) was an isoalkanes mixture containing 80 to 81 % (C-| 6)isohexadecanes, 3% (C-| 3)isotridecanes, and 16 to 17% (C-^isododecanes.

[0132] Silver particles (Ag1 ) fatty acid ester lubricated silver flakes having a mean particle size of 3.9 μιη, surface area of 0.86 m²/g, apparent density of 1 .58 g/cm³, and a tap density of 3.02 g/cm³.

[0133] Silver-coated nickel particles Ag/Ni-40, Ag/Ni-30, and Ag/Ni-15 had concentrations of silver in Ag/Ni-40, Ag/Ni-30, and Ag/Ni-15 were 40 wt%, 30 wt%, and 15 wt%, respectively, based on total weight of the silver-coated nickel particles. The Ag/Ni-40, Ag/Ni-30, and Ag/Ni-15 had mean particle sizes of 8 to 9 μιη, 15 to 16 μιη, and 35 to 45 μιη, respectively. The Ag/Ni-40, Ag/Ni-30, and Ag/Ni-15 had apparent density of 3.0 g/cm³, 3.1 g/cm³, and 3.4 g/cm³, respectively.

[0134] Tin particles (Sn1 ) were spherical particles consisting essentially of 99.99 wt% Sn and having an apparent density of 7.28 g/cm³. The particles had a particle size of from 25 to 45 microns with a -325/+500 mesh particle size distribution.

[0135] Multi-walled carbon nanotubes (MWCNT1 ) had an outer diameter of from 50 to 100 nm and length of from 5 to 20 μιη. Derivatized carbon nanotubes (DCNT1 ) were graphenated MWCNT that had > 99.9 wt% purity, and an outer diameter of from 5 to 20 nm and a length of from 5 to 50 μιη.

[0136] Vinyl-functionalized Polydimethylsiloxane (VFPDMS1 ) : this primary organosiloxanes was a vinyl-functionalized polydimethylsiloxane having dynamic viscosity of from 40,000 to 70,000 Pa.s,

[0137] A chain extender/crosslinker was a trimethylsiloxy-terminated dimethyl methylhydrogensiloxane (CE/CL1 ) liquid having a dynamic viscosity of 55 cSt (55 mm²/s). Another chain extender/crosslinker was dimethylvinylsiloxy-terminated methylhydrogencyclosiloxane (CE/CL2).

[0138] Adhesion promoter (AP1 ) was an a 3:2 (wt/wt) mixture of bis(alpha,omega- glycidoxyalkyl)-dialkyl/(alkyl,alkenyl)siloxane adhesion promoter with a kinematic viscosity of 17 cSt (17 mm²/s) and bis(alpha,omega-glycidoxyalkyl-D3 to D6 alkyl,hydrogencyclosiloxane), wherein there are two bis(alpha,omega-glycidoxyalkyl-D3 to D6 organo,hydrogencyclosiloxanyl moieties, which are linked to each other via an alkylene- dialkylsiloxanyl-alkylene linker.

[0139] Catalyst (CAT1 ) was a microencapsulated platinum catalyst in the form of shell- core particles, wherein CAT1 contained 0.008 wt% Pt, wherein the encapsulant or shell was a cured vinyl-terminated polydimethylsiloxane and the core comprised a platinum- ligand complex.

[0140] Silica glass beads (SGB1 ) were solid spherical soda-lime glass particles having a maximum diameter of from 75 to 90 μιη and a specific gravity of from 2.3 to 2.7.

[0141] Non-limiting examples of the invention follow. They illustrate some specific embodiments and aforementioned advantages. The invention provides additional embodiments that incorporate any one limitation, alternatively any two limitations, of the Examples, which limitations thereby may serve as a basis for amending claims. [0142] Preparation Method: The curable silicones of the examples were prepared by mixing the Vinyl-functionalized Polydimethylsiloxane 1 and any multi-walled CNTs or treated CNTs, if used, to form a master batch (MB1 ). Mixing to form MB1 was done with an EXAKT Three Roll Mill (model no. 80E, Exakt Advanced Technology) in 5 passes using a 5 to 70 μιη gap at 30 revolutions per minute (rpm). To a pot of a 0.5 liter planetary mixer (Custom Milling and Consulting, Fleetwood, Pennsylvania, USA) add HV1 ; AP1 ; Ag1 ; any Sn1 ; any Ag/Ni-40; an aliquot of MB1 if CNTs are used; Vinyl-functionalized Polydimethylsiloxane 1 ; and, if used, solid silica glass beads (SGB1 ); and mix resulting contents for 5 minutes at 15 Hertz and 5 minutes at 30 Hertz to wet-out and disperse electrically conductive filler to give a precursor mixture. To the precursor mixture add the chain extender/crosslinker CE/CL1 (or both CECL1 and CE/CL2) and the microencapsulated platinum catalyst (CAT1 ), and mix gently to prevent heating, and de-air the pot to give a curable silicone of any one of Examples 1 to 7. The amounts of the ingredients of the hydrosilylation-curable organosiloxane and the curable silicone prepared therefrom were chosen so as to give the wt% concentrations listed below in Tables 1 and 2, respectively.

[0143] Table 1 : Hydrosilylation-curable organosiloxanes; Examples 1 to 7.

[0144] Table 2: Curable silicones; Examples 1 to 7.

Ag/Ni

(wt%)

(particles

with Thixotropic Hydro¬

40%Ag Filler carbon Organo¬

Ex. Ag1 Sn1 and 60 MWCNTs Vehicle siloxane^* Other

No. (wt%) (wt%) % (wt%) (wt%) (wt%) (wt%)

^*See Table 1 unless noted otherwise.

[0145] The curable silicone compositions (CSCs) of Ex. 1 to 7 may be directly characterized by thixotropic index, total silver concentration, total electrically conductive metal concentration, and indirectly by characterizing the electrically conductive silicone adhesive (ECSA) resulting from curing the CSCs by volume resistivity, adhesion, and theoretical concentration of silver (if all of hydrocarbon vehicle HV1 had been removed during curing). These characterizations are shown below in Table 3.

[0146] Table 3: Direct and indirect characterizations of curable silicone compositions (CSC); Examples 1 to 7.

[0147] As illustrated by the foregoing examples and described above, the total silver concentration may be kept in the range of from 19.5 to < 43 wt% and the total electrically conductive metal concentration below 75 wt%, and yet the volume resistivity of the resulting ECSA remains below 0.0030 Ω-cm, alternatively < 0.0020 Ω-cm, alternatively < 0.0010 Ω-cm, alternatively < 0.00080 Ω-cm. In some embodiments, the thixotropic index of the curable silicone may be adjusted in the range from 4 to 10 (e.g., 3.8 to 9) by varying concentration of carbon nanotubes within a range of from 0.4 to 2.2 wt% (e.g., from 0.80 to 1.0 wt%). The foregoing wt% are based on weight of the curable silicone. Embodiments of the present invention method include such adjusting.

[0148] The below claims are incorporated by reference here as correspondingly numbered aspects except where "claim and "claims" are rewritten as "aspect" and "aspects."

55

Claims

What is claimed is:

1 . A curable silicone composition containing a curable organosiloxane composition, silver, and at least one electrically conductive metal other than silver, the curable silicone composition being characterizable by a total concentration of silver of less than 45 weight percent and lacking gold and copper metals while the composition remains curable to an electrically conductive silicone adhesive having a volume resistivity of less than 0.003 Ohm-centimeter measured according to Volume Resistivity Test Method without increasing the concentration of silver in the curable silicone composition to 45 weight percent or higher and without increasing total concentration of electrically conductive metal in the curable silicone composition to

80 weight percent or higher; wherein the total concentration of all solids in the curable silicone composition is at least 60 weight percent.

2. A curable silicone composition comprising a blend of the following ingredients:

A hydrocarbon vehicle at a concentration of from 7 to 20 weight percent based on weight of the curable silicone composition, wherein the hydrocarbon vehicle is characterizable by a boiling point from 100 to 360 degrees Celsius;

A curable organosiloxane composition at a concentration of from 5 to 40 weight percent based on weight of the curable silicone composition; and

Electrically conductive filler consisting essentially of a combination of a silver filler and an enhancing filler lacking silver, copper, gold, and aluminum;

Wherein the silver filler is silver particles or a combination of silver particles and silver-coated core particles, wherein the silver particles are at a concentration of from 5 to 43 weight percent, the silver-coated core particles when present are at a concentration of from > 0 to 48 weight percent, and the total concentration of silver is from 19.5 to 43 weight percent, all based on weight of the curable silicone composition; and

Wherein the enhancing filler is metal particles of tin, molybdenum, zinc, bismuth, indium, lithium, tungsten, nickel, iron, palladium, platinum, or a metal alloy or combination of any two or more of the foregoing metals; carbon nanotubes; electrically non-conductive filler particles; or a combination of any two or more of the metal particles, carbon nanotubes, and electrically non-conductive filler particles; wherein the metal particles, when present, are at a maximum

concentration of 70 weight percent, the carbon nanotubes, when present, are at a maximum concentration of 5.0 weight percent, the electrically non-conductive filler particles, when present, are at a maximum concentration of 50 weight percent, and the enhancing filler is at a total concentration of from 30 to 70 weight percent, all based on weight of the curable silicone composition.

The curable silicone composition of claim 2 characterizable by a volume resistivity less than 0.0030 Ohm-centimeter measured according to Volume Resistivity Test Method.

The curable silicone composition of claim 2 or 3 characterizable by the following limitations:

Wherein the hydrocarbon vehicle is an alkanes mixture having an initial boiling point greater than 150 degrees Celsius and an end boiling less than 300 degrees Celsius and the hydrocarbon vehicle is at a concentration of from 7.0 to 18 weight percent based on weight of the curable silicone composition;

Wherein the curable organosiloxane composition comprises at least one diorganosiloxane compound, a catalyst, and an adhesion promoter; wherein the at least one diorganosiloxane compound has on average per molecule at least 1 reactive moiety, wherein each reactive moiety independently is an alkenyl moiety, Si-H moiety, Si-OH moiety, Si-OR moiety, wherein R is (C-_| -C-| o)hydrocarbyl,

-C(0)(C-| -C-| o)hydrocarbyl, or -N=CR¹ R², wherein each of R¹ and R²

independently is (Ci -Ci o)hyc!rocarbyl ₀r R¹ and R² are taken together to form a (C2-C-| o)hydrocarbylene; and wherein the at least one diorganosiloxane compound is at least 50 weight percent of the curable organosiloxane composition;

Wherein the concentration of silver particles is from 10 to 40 weight percent, the concentration of silver-coated core particles is from 0 to 38 weight percent, and the total concentration of silver is from 19.8 to 40 weight percent, all based on weight of the curable organosiloxane composition;

Wherein the enhancing filler is tin particles, a combination of tin particles and carbon nanotubes, electrically non-conductive filler particles, or a combination of carbon nanotubes and electrically non-conductive filler particles, and the enhancing filler is at a total concentration of from 36 to 67 weight percent, all based on weight of the curable silicone composition; and

Wherein the curable silicone composition is characterizable by a volume resistivity less than 0.0030 Ohm-centimeter measured according to Volume Resistivity Test Method. The curable silicone composition of claim 4, characterizable by the following limitations:

Wherein the hydrocarbon vehicle is an alkanes mixture;

Wherein the curable organosiloxane composition comprises at least one diorganosiloxane compound, at least one organohydrogensilicon compound, a hydrosilylation catalyst, and an epoxy-functional adhesion promoter; wherein the at least one diorganosiloxane compound has on average per molecule at least 1 alkenyl moiety and the organohydrogensilicon compound has on average per molecule at least 1 Si-H moiety; and wherein the at least one diorganosiloxane compound is from 60 to 80 wt% of the curable organosiloxane composition;

Wherein the concentration of silver particles is from 15 to 25 weight percent, the concentration of silver-coated core particles is 0 weight percent, and the total concentration of silver is from 20.0 to 35 weight percent, all based on weight of the curable organosiloxane composition;

Wherein the enhancing filler is tin particles wherein the tin particles are at a concentration of from 55 to 69 weight percent, a combination of tin particles and carbon nanotubes wherein the carbon nanotubes are at a concentration of from 0.5 to 1 .5 weight percent and the tin particles are at a concentration of from 35 to 65 weight percent, electrically non-conductive filler particles are silica glass particles at a concentration of from 25 to 35 weight percent, or a combination of carbon nanotubes and silica glass particles wherein the carbon nanotubes are at a concentration of from 0.5 to 1 .5 weight percent and the silica glass particles are at a concentration of from 25 to 35 weight percent, and the enhancing filler is at a total concentration of from 40 to 66 weight percent, all based on weight of the curable silicone composition;

Wherein the carbon nanotubes are single-walled carbon nanotubes, multi- walled carbon nanotubes, derivatized carbon nanotubes or a combination of any two or more of the single-walled carbon nanotubes, multi-walled carbon nanotubes, and derivatized carbon nanotubes; and the concentration of carbon nanotubes is from 0.5 to 2.0 weight percent based on weight of the curable silicone composition; and

Wherein the curable silicone composition is characterizable by a volume resistivity less than 0.0010 Ohm-centimeter measured according to Volume Resistivity Test Method. The curable silicone composition of claim 5, characterizable by the following limitations:

Wherein the alkanes mixture is an isoalkanes mixture comprising at least two of (Cg-Ci 2)isoalkanes, at least two of (C-^-C-^isoalkanes or at least two of

(C-| 6-C22)^{isoalkanes ancl tne} hydrocarbon vehicle is at a concentration of from 8 to 12 weight percent based on weight of the curable silicone composition;

Wherein the curable organosiloxane composition is hydrosilylation curable and comprises the at least one diorganosiloxane compound, the at least one trimethylsiloxy-terminated dimethyl organohydrogensilicon compound, a microencapsulated hydrosilylation catalyst, and a bis(alpha,omega-glycidoxyalkyl)- dialkyl/(alkyl,alkenyl)siloxane; wherein the alkenyl of the diorganosiloxane is vinyl and the at least one diorganosiloxane compound has on average per molecule at least 1 .1 vinyl moieties, the at least one trimethylsiloxy-terminated dimethyl organohydrogensilicon compound is and has on average per molecule at least 1 .1 Si-H moieties, or the least one diorganosiloxane compound has on average per molecule at least 1 .1 vinyl moieties and the at least one organohydrogensilicon compound has on average per molecule at least 1 .1 Si-H moieties; wherein the at least one diorganosiloxane compound having vinyl moieties is from 70 to 75 wt% of the curable organosiloxane composition; wherein the at least one trimethylsiloxy- terminated dimethyl organohydrogensilicon compound is from 1 to 5 weight percent, the microencapsulated hydrosilylation catalyst is from 10 to 15 weight percent, and the bis(alpha,omega-glycidoxyalkyl)-dialkyl/(alkyl,alkenyl)siloxane is from 5 to 10 weight percent, and together the organohydrogensilicon compound, microencapsulated hydrosilylation catalyst, and the bis(alpha,omega- glycidoxyalkyl-D3 to D6 alkyl,hydrogencyclosiloxane are from 20 to 30 wt% of the curable organosiloxane composition;

Wherein the concentration of silver particles is from 15 to 25 weight percent, the concentration of silver-coated core particles is 0 weight percent, and the total concentration of silver is from 20.0 to 25 weight percent, all based on weight of the curable organosiloxane composition;

Wherein the enhancing filler is tin particles wherein the tin particles are at a concentration of from 60 to 65 weight percent, a combination of tin particles and multi-walled carbon nanotubes wherein the multi-walled carbon nanotubes are at a concentration of from 0.7 to 1 .3 weight percent and the tin particles are at a concentration of from 39 to 64 weight percent, silica glass particles at a

concentration of from 28 to 32 weight percent, or a combination of multi-walled carbon nanotubes and silica glass particles wherein the multi-walled carbon nanotubes are at a concentration of from 0.7 to 1 .3 weight percent and the silica glass particles are at a concentration of from 28 to 32 weight percent, and the enhancing filler is at a total concentration of from 40.5 to 65.3 weight percent, all based on weight of the curable silicone composition; and

Wherein the curable silicone composition is characterizable by a volume resistivity less than 0.00090 Ohm-centimeter measured according to Volume Resistivity Test Method.

A curable silicone composition comprising a blend of the following ingredients:

An isoalkanes mixture comprising at least three of (C-|2-Cl 6)^isoalkanes and has an initial boiling point of greater than 210 degrees Celsius and an end boiling point of less than 270 degrees Celsius and the hydrocarbon vehicle is at a concentration of from 9 to 1 1 weight percent based on weight of the curable silicone composition;

A hydrosilylation-curable polydimethylsiloxane composition comprising at least one vinyl-functional polydimethylsiloxane compound having on average per molecule at least 1 vinyl moieties, at least one trimethylsiloxy-terminated dimethyl methylhydrogensilicon compound having on average per molecule at least 1 .1 Si-H moieties, a microencapsulated platinum hydrosilylation catalyst, and

bis(alpha,omega-glycidoxyalkyl)-dialkyl/(alkyl,alkenyl)siloxane, and

bis(alpha,omega-glycidoxyalkyl-D3 to D6 alkyl,hydrogencyclosiloxane; and wherein the vinyl-functional polydimethylsiloxane compound is from 70 to 75 weight percent, the trimethylsiloxy-terminated dimethyl methylhydrogensilicon compound is from 1 to 5 weight percent, the microencapsulated hydrosilylation catalyst is from 10 to 15 weight percent, the bis(alpha,omega-glycidoxyalkyl)-dialkyl/(alkyl,alkenyl)siloxane is from 1 to 10 weight percent, and the bis(alpha,omega-glycidoxyalkyl-D3 to D6 alkyl,hydrogencyclosiloxane is from 0 to 7 weight percent, all of the curable polydimethylsiloxane composition; and wherein together the trimethylsiloxy- terminated dimethyl methylhydrogensilicon compound, microencapsulated hydrosilylation catalyst, and the bis(alpha,omega-glycidoxyalkyl)- dialkyl/(alkyl,alkenyl)siloxane, and bis(alpha,omega-glycidoxyalkyl-D3 to D6 alkyl,hydrogencyclosiloxane are from 20 to 30 wt% of the curable organosiloxane composition;

Wherein the silver filler is silver particles at a concentration of from 19.5 to 25 weight percent and total silver concentration is from 19.5 to 25 wt% based on weight of the curable polydimethylsiloxane composition; and

Wherein the enhancing filler is a combination of tin particles and multi- walled carbon nanotubes wherein the multi-walled carbon nanotubes are at a concentration of from 0.7 to 0.94 weight percent and the tin particles are at a concentration of from 56 to 64 weight percent, all based on weight of the curable silicone composition.

. The curable silicone composition of claim 7 characterizable by a volume resistivity less than 0.00090 Ohm-centimeter measured according to Volume Resistivity Test Method.

. The curable silicone composition of any one of the preceding claims, wherein the curable silicone composition is characterizable by a Thixotropic lndex(n.-|/n.i o) ^of from 3 to 10.

0. The curable silicone composition of any one of the preceding claims, wherein the curable silicone composition lacks electrically conductive particles other than the silver particles and any silver-coated core particles, metal particles, and carbon nanotubes.

1 . An electrically conductive silicone adhesive that is a product of curing the curable silicone composition of any one of the preceding claims, wherein the electrically conductive silicone adhesive is characterizable by a volume resistivity of less than 0.0030 Ohm-centimeter measured according to Volume Resistivity Test Method.

2. An electrical device comprising first and second electrical components having opposing surfaces and the electrically conductive silicone adhesive of claim 1 1 disposed between and in adhering operative contact with the opposing surfaces of the first and second electrical components, wherein the first and second electrical components are disposed for electrical operative communication with each other via the electrically conductive silicone adhesive, wherein the electrically conductive silicone adhesive is characterizable by a volume resistivity of less than 0.0030 Ohm-centimeter measured according to Volume Resistivity Test Method.

13. A method of manufacturing an electrical device comprising first and second electrical components having surfaces and an electrically conductive silicone adhesive, the method comprising depositing the curable silicone composition of any one of claims 1 to 10 onto one or both surfaces of the first and second electrical components, and orienting the first and second electrical components so that their surfaces are opposing each other to give a preassembly comprising the curable silicone composition disposed between and in physical contact with the opposing surfaces of the first and second electrical components; and curing the curable silicone composition between the opposing surfaces of the first and second electrical components to give an electrical device comprising the first and second electrical components and an electrically conductive silicone adhesive disposed between and in adhering operative contact with the opposing surfaces of the first and second electrical components such that the first and second electrical components are disposed for electrical operative communication with each other via the electrically conductive silicone adhesive, wherein the electrically conductive silicone adhesive is characterizable by a volume resistivity of less than 0.0030 Ohm-centimeter measured according to Volume Resistivity Test Method.