CA1103839A - Solventless silicone resins - Google Patents

Abstract

Abstract of the Disclosure There is provided by the present invention a process for producing a solventless silicone resin having a viscosity at 100%, varying from 200 to 5,000 centipoise at 25°C, comprising adding a mixture of water and alcohol to the desired organochlorosilanes taking the silicone alkoxylate and washing it repeatedly with alcohol until the acid content is at least below 1000 parts per million, adding an alkali metal hydroxide to reduce the acidity of the silicone alkoxylate such that it does not exceed 100 parts per million, and then adding sufficient water such that the amount of water that is added is between 0.2 to 0.8 moles of water per mole of hydrocarbonoxy radicals in such silicone hydrolyzate The excess alcohol and water is stripped off to give the solvent-less silicone resin of the instant invention having an organo to Si ratio varying from 1.1 to 1.9, having a silanol content varying from 1 to 4% by weight and a hydrocarbonoxy content that varies from 7 to 14% by weight.
A less preferred solventless system can be obtained by simply mixing in an organic solvent, a high alkoxy containing silicone resin produced 'by traditional procedures, and a high silanol silicone resin also produced by traditional procedure and stripping off the solvent.

Description

! ~
Background of the Invention ,, ',, The present invention relates to a p~ocess for producing a sol~rentless ~silicone resin and rnore particularly the present inven-j tion relates to a solventless silicone resin and a process for S I producing a solventless silicone resin where such silicone resin ~ has a vi~co~ity varying anywhere froIm 200 to 5, 000 centipoise at

2~C.
Silicone resins are well lcnown in the art. Such silicone resins usually comprise a resin composed of trifunctional siloxy ln units and d~Eunctional siloxy UIlitS with a silanol content varying anywhere rom 0.1 to 8% and optionally an alkoxy content varying anywhere from 0 to 4% by weight. Such silicone resins composed of trifunctional silo~r units and difunctional siloxy unita are the j most prevalent type of silicone resins for orming varnishes and 1 silicone based pain~s, as well as for forming molding and encap j ~ulating silicone compositions. It should be noted that such j silicone resins are desired in the above applications since it has been found that products produced from silicones and silicone resin 1 usually have better high temperature stability and weatherability I properties as compared to traditional organic compositions.
There is also present in silicone chemistry, silicone resins j composed of monofunctional siloxy units and tetrafunctional siloxy units with optionally difunctional 6;10~t units. However, such ' resins have been found to be more use~ul in the production of 2S surfactants and silicone adhesives r ather than in the fabrication of 1 ~, i 1'

3~ 60 SI ~71 ¦' coatings. Accordingly, a highly success~ul silicone coating usually, . comprises one having trifunctional siloxy units and di~unctional ~iloxy units since the combination of such un its in a silicone re sin give the resin, when it cures, the appropriate hardness while at ¦ ~ the same tLme giving it some flexibility such that it can in some ¦I cases withst~nd extreme temperature cycling which i~ not posq,ible ~I with organic resins and compositions. An e~ample of a suitable ¦ silicone re~iin to be found in the prior a.rt is, fox instance, that ¦ disclosed in the patent o~ oedel, USP 31 846, 358, which ,, -¦ issued November 5, ].974. This referenee provldes -the . production of a silicone resin without the use of a wa,ter immiseible 1~ I organic 601vent, but by the use of 2n aliphatic a:Lcohol.
Simply the Roedel process comprises taking a mixture of I alcohol and water in the app.ropriate amounts, adding it to the I organochlorosilanes, and producing the appropriate àlkoxylated silo~ane. The alkoxylate is then washed with an aliphatic alcohol such that the acidity of the silicone alkoxylate is in the area of 1000 parts per million of acid or below. Then there is added an I 1 -alkali metal hydroxide to the silicone hydrolyzate to further reduce , the acidity to the desired level.
Finally, there is added to the sllicone alko~srlate additional ~( water and an aliphatic alcohol as a solubili~ing agent to hydroIyze ¦~ most of the alkoxy groups in the silicone alkoxylate to form the ¦I desired silicone resin therefrom. The alcohol is then stripped 1, from the isilicone resin to leave behind a solid mass or th~ resin may 1, be cut in organic solvent for use in various products and : I . `I ,`

;~ compositions such as varnishes, silicone paints, molding composi-tions and also as a sil;cone resin encapsulant. However, while such silicone resins have many advantages they have one well-known l! disadvantage, they callnot be utili~ed as solventless resins in liquid ¦¦ form. Accordingly, in most cases, to utilize such silicone resins, it i9 necessary to ~ltili~e an organic sol~ent to dissolve the silicone resin so thatit is present in anywhere from 5% to 90% silicone solids in solution 60 that it can be utilized and incorporated in various compo sition 8 .
It should be noted with respect to the Roedel process, in Column 6 beginning w*h line 42, Roedel points out that there is ¦ sufficient water added to his silicone resin such that most of the ¦ alkoxy and halogen groups are removed from his final silicone I resin product. In addition, Roedel points out specifically in I Column 7, line 32, tbat his silicone resin has an alkoxy content that varies from 0. 2 to 4. 0% by weight. Further, it should be noted that in Example l, the silicone resin product that was obtained by the ¦ procedure of Roedel was a hard b~ittle solid. A.ccordingly, this 1l disadvantage of the silicone resin of Roedel, that is in order for it to 1l be a liquid at room temperature, it has to be dissolved in an organic solvent and is a disadYantage that has gained more prominence i recently.
Accordingly, organic solve~ts while suitable or dissolving I~ the æilicone resin and preparing an appropriate solu~ion have the ¦, disadYantage that they have to be disposed of or evaporated ater ), the silicone resin has been incorporated into a composition.
:Accordingly, because oE restrictions in many geographical areas l i ,, , ¦I much care and thought has to be allotted to the proper handling and disposal of such solvents after they have been utilized in the particular process.
Acc~rdingly, the use of organic solvents results in unnecessary e~pense in whatever process they are utilized in, both in their initial cost and in their final disposal.
It should be noted t~at while the l~oedel patent involved a process which did away with the use of hydxocarbon solvents in the actual process of producing the silicone resin, nevertheless, because of the form that the final product is produced a hydrocarbon solvent is needed for the final silicone resin product to be utilized properly.
~ccordingly, for the above reasons, it was highly desirable :
: to develop a solventless silicone resin system, that i6, where the final silicone resin product would be a liquid of desirable low visco~ity at room temperatuxe, such that a solvent i9 not needed.
i~ . Solventless silicone resin system. is, for Lnstance~ to be found in the patent of Mink, USP 3, 948, 848, which has recently issued. Such solventless silicone resins as disclosed in this paten~
conmprise a two-component silicone resin system in which one-component comprises a vinyl-cont.aining copolym.er com.posed of trifunctional siloxy units and di~unctional siloxy UtlitS, and the eecond com.ponent comprises a copolym.er containing hydrosiloxy units ¦ ;
.~ in which the unit8 themselves are selected from trifunctional siloxy units and difunctional siloxy unitæ. In such com.positions ~; 25 in either one or th~ other of the two components there is present a `:~ platinum. catalyst. If it is desired to cure the composition of ~ this patent the two compositions a~e mi~;ed together and .~ 39 60 SI 171 cured in the presence of a platinum catalyst to form a silicone '~ encapsulating composition. It is also disclosed that such a compo-, sition can be utilized as a one- con~ponent systern by the use of I inhibitors. It is also disclosed that other les~s expensivc catalyst s I
I may be ~sed in such compositions by the patentee but nevertheless, ' ' it has been ound by experience and ac, the patent states that I ~.
, platinum is the most preerred catalyst or such curing reactions. I
While such composition has been found to be an appropriate ¦
I encapsulating composition, it has several disadvantages. The rnost liG pronounced disadvantage i8 that it is quite expensive because of the us,e of two components and also the platinum catalyst. Further, such two component systems are di;Eficult to work with by inexper-ienced applicators. Another disadvanta~e of such a compo sition as ¦ that disclosed in the ~oregoing Mink patent is that the cured compo-~
lS I sition does not have desîrable thermal stab;lity at temperatures ¦
abo~re 250 C for extended periods of time. The reason fox this is I that the ethylene chain that is ormed by the hydrogen atom adding ! on to the vinyl group in the curing of the silicone resin result s in j i an ethylene bond which is not that stable at ten~peratures exceeding i above 250 C. Accordingly, both in terms of expense and in terms , of properties, the above Mink composition while having many ¦
¦ advantages has thoæ disadvantages which detract from its utility.
¦ Another developrneD~ in the so~ventless systems is that to ' be found in Magne, USP 3, 978, 025. The Magne process has two '~
disadvantages while it does produce a suitable solventless silicone ¦
¦I resin system. In the Magne process, while the chlorosilanes are hydroly~.ed in an alcohol-water mixture, neveltheless, in order to maintain a homogeneous medium Magne teaches the use of an ' organic solvent. Accordingly, his process has the disadvantage of ~ I

S~lj"7~ j,ii gj~ ;S~ 'ti,i' 7i~ A~ If~ tliltli ~? ';~" ~ 'Mi ~ ': 'i il i:

~f~3~ ~ 60SI- 171 i~ i the handling and disposal of such oxganic solvents.
l Another clisadvantage in Magne's process is that he discloses :in Column 3 the use of a large excess of water in his final .
Il hydrolysis step. ~ ~ . .
¦, ~ccordingly, it was highly desirable to develop a solvent~
¦ less silicone resin and a process for developing a solventless silicone resin having the appropriate low viscosities at room. I , temperature, that IS, a viscosity in the neighborhood of 200 to 5, 000 1 .
centipoise at 25C, or preferably viscosities of 400 to 2, 000 centi~
poise at 25C, which do not utilize a hydrocarbon solvent in the process for their production, and which are ineæpensive to produce and use. Accordingly, it i6 one object o the present invention to ' .
provide for an improved process for producing solventless silicone resins without using hydxocarbon fiolvents.
It is an additional object of the present invention to provide for an improved solventless silicone resin system. which is inexpensive and simple to produce. I ~l . It is an additional ;:~bject of the present inventio~ to provide ~r a solventless silicone reisin sy~tem. which has a viscosity varying anywhere from 200 to 5, 000 centipoise at 25"C.
It is still an additional object o the present insrention to ¦ provide for a 601ventless silicone resin having a viscosity 1:hat does I I
not eæceed 5, OOû centipoise at 25C that iB composed of trifw;~ctional , .
~ siloxy units and diunctional siloxy units having a silanol content i .
~ that varies from 1 l:o 4% and having a m.ethoxy content that varies ~ .
¦ from 7 to 14% by weight, .~f~ 6 0 S I 171 It is ~et an additiona.l obj~ct of the pre~;ent invention to provide for a process for producing a sol~rentless silicone resin s~rstem which is eminently f;uitable for the production of silicone I paints a.nd sillcone valnishcs. These and other objects of the l~ present invention are accomplished by meal~s o thc disclosure set orth hereinbelow. ~ j ¦ Sumrrlary o the Invention : In accordance with the above objects, there is provided by the present inyention a process for producing a solventless silicone resin having a viscosit~ at 100% solids varying from Z00 I ::
to 5, 000 centipoise at 25(~, corrlprising ta) adding to organo-chlorosilanes o the formula, 1~ ' Ra Si C14_a I where R is ~elected from the class consisting of alkyl radicals, l 5 I cycioalk~l radicals, alkenyl radicalri, aryl radicals and fluoroalkyl t radicals, a~l having up to 8 carbon atoms, and mixtures thereof where a is l or 2, from 0. 05 to 0. 2 .part of water, and rom 0.1 ! to l part of an aliphatic alcohol of up to 3 carbon atoms, per part ¦ o organochlorosilanes to form a silicone alko~ylate; (b) re:ELuxing 20 ii the alkoxylate; (c) inserting additional amounts of said aliphatic ~.
alcohol to sald alkoxylate and removing said alcohol until the acid i content of said alkoxylate is below 1000 parts per r~lillion; (d) ' adding an alkali metal hydroxidè\ to the said al.koxylate until its ~ acid content does not exceed lO0 parts per million; (e) adding 25 ¦ water to said alkoxylate such that the amount o water that is added 7 ¦ I

is from 0. 2 to 0. 8 moles of water per mole of hydrocarb~noxy radicals in said alkoxylate; and ~f) he~ting said alkoxylate so as Il to complete the hydrolysis reaction with the additional water to li obtain the deæired resin product. In step (b) ~Cl is removed by 5 I distillation and the reaction dxiven to~ard completion. In any case, ~ some distillation by heat of the e~ccss acid iB deslrable since that ¦ will remove a laxge amount o the acid rom the silicone alkoxylate without requiring repeated washing with the aliphatic alcohol.
To remove the small amounts of acid, it is necessary af~er the refluxing to wash the silicone alkoxylate with quantities of an alipha~ic alcohol and xemove the alcohol phase by heating the silicone alkoxylate ~o a~ to strip of the alcohol and acid or by physical separation of the acid-alcohol phase. Such stripping procedures may be carried out àny number of times untiL ~prefer-ably, the acid content i6 below lO00 parts per million. Finallr, it is desirable to reduce the acid content to lOO parts per million or below and moxe pxeferably io 50 parts per million or below by adding an alkali metal hydroxide such as, potassium hydroxide, ¦ to the silicone alkoxylate to effect such acid reduction. The ¦
20 ¦ reason the alkali metal h~rdrc>xide is not used initially in the reduction of acidity is that large quantities of the allcali metal hydroxide would be utilized and the salts th~t would be ~orrn~ed as a reRult of such neutralization reactions have an undesirable ef~ect Il on the electrical properties o the cured silicone resin.
Z5 ¦1 Accordingly, it i3 not de~irable to add the alkali metal hydroxide to the silicone alkoYylate vmtil moat oi ~he acid has been removed I

', 33~
and then the alkali metzl hydroxide is added to simplify the final acid reduction to the appropriate level.
~, In addition~ it should be noted that it is desired to reduce `
I the acidity of the silicone res;ll alkoxyl~te to the appropriate l~ level as indicated abov~ since if watel is added in the final hydrol-~ ysis and there is a lal~ge amount of acid present then what rcsults j i is that the silanol groups are condensed out to result in a high viscosity silicone resin and one that has too few silanol groups to effect proper cure of the silicone xesin to form a hard coat or film in the final application of the resin.
Accordingly, after the acidity of the alkoxylate has been red~ced then the appropriate amount of water is simply a~ded to ¦ efect the final silicone resin product. Further, in the final ¦ addition of water, it is desirable that the water be added in in-crements so as to eect better reaction in the final hydrolysis , reaction~ It is also desirable that some alcohol optionally be used in the inal hydrolysis of the silicone resin alkoxylate so that the silicone alkoxylate and water are æolubilized, thus making it ~ easier to react with the water~ ¦

j E`inall~, it should be noted that the ratio of water to alkoxy ' groups, that iB, the ratio of 0~ 2 to 0. 8 moles of water per mole ~ of alkoxy radicals in the silicone alkoxylate, that is, of the ! moless of water that is added to the inal hydrolysis is critical~

If too little water is added then sufficient silanol groups are not i in~parted to the silicone resin product and as a result the silicone `
¦ resin product will not cure properly~ If more than 0. 8 moles of I ¦ .

_ 9 _ .

339 ~o SI 171 ', .

water, is added then too many of the hydrocarbonoxy radicals or alkoxy radicals will hydrolyze in the silicone alkoxylate resulting in the hydrolyzate cross-linking more than is desired and there 1 re~ults a silicone resin product of high viscosity.
¦~ Accordingly, it must be pointed out that the most critical aspect of the process of the instant invention is the concentration of moles of water that is utili~ed per mole of hydrocarbonoxy radicals in the silicone alko~{ylate în the final hydrolysis reaction.
~ Utilizing the above process there is obtained by the process of the present invention a silicone re sin product having an organo to Si ratio that varies from 1. 0 to 1. 9:1, a silanol content that varies generally from 1 to 4% by weight and more preferably 1 to 3% by weight and a hydrocarbonoxy content that varies from 7 to 14% by ¦ weight and more preferabl~r 7 to 12% by weight.
! The solventless silicone resin may have at room temperature ¦ in the absence of a solvent, that i8, at 100% solids, a viscosity that varies anywhere from generally 200 to 5, 000 centipoise at 25C~I
and more preferably a viscosity varying from 500 to 2, 000 centipoise j at 25 C. Such silicone resins may be cured with a metal salt of , a carboxylic acid at a concentration of aIlywhere ~rom . 05 to 0. 5%
by weight of the metal by weight of the total silicone resin wherein , the metal is selected rom rnanganese to zinc in the Periodic Table . ~ with the exception that the metal salt of iron cannot be used at a concentration higher than . 01% by weight of the metal and more , preferably at a concontration no higher than . 005% by ~eight of the total silicone resin solids and must be used in corribination with j Il I

3~ , , I, one of the other metals. A more preferable cuxing system for such' ¦, ~ilicone resins is a cnbination of an amine functional silane and ¦~ more specifically any of the amino propyl triethoxy silanes in combina-tion with a n~etal salt of a carboxylic acid. There is utili~ed anywhere I from 2S to 75% by weight o the rnetal salt of a carboxylic acid in comb;nation with 25 to 75% by weight o the arnine functional silane and where the total combination of catalysts varies from 0. 5 to 4. 0% by weight of the total silicone xesin product.
¦ The most preferred combination catalyst that can be utilized I is a carboxylic acid salt o zinc in combination with gamma-amino-propyltriethoxysilane. Such a catalyst system is desired because I , ,it initiates cure of the silicone resin composition at temperatures ~ i of 150 C while the other cat alyst systems initiate cure at terxlperà~
tures above 200 and more usually at 250C. ¦
I ~ I
I The above process for the solventless silicone resin system ¦
'' is the most preferred in accordance with the instant invention.
However, in the alternative there n~ay be prepared another type of l solventless silicone resin system in accordan oe with the disclosure I of the instant case which is almost as desirable and has almost the I same properties as the silicone resin produced by the process set ~' I ~orth herein above. Accordingly, in the alternatiYe there rnay be produced a solventless silicone resin system having a viscosity at ` 100% solids varying frorn 200 to 5, 000 centipoise at 25C:, comprising i ', (a) from 35 to 65% by weight of a first silicone resin wherein said resin is composed of organo trifunctional siloxy units and diorgano i difunctional siloxy units where the organo to Si ratiD varies rom ~
1~ 1. 0 to 1. 9:1; a hydrocarbono~ content that varies from 10 to 25% .
¦I by weight and a silanol content that is less than 1% by weight, and , , ' ~ 3~39 ~, (b~ from 35 to 65% by weight of a second silicone resin compo sed of monoorgano txifunctional siloxy units and diorgano difunctional siloxy units where the organo to Si :ratio varies from 1. 0 to 1. 9:~, and has a hydrocarbonoxy content that varie s from 0 to ~% by weight, I and a silarlol content that varies from 3 to 8% by weight, where the I organo groups in said resins are selected from the class consisting ¦ o allcyl radicals, cycloalk~l radical~, alkenyl radicals, ar yl radicals and fluoroalkyl radicals all having up to 8 carbon atoms ~ and mixtures thereof.
¦ The two silicone resins disclosed in the above solventless system are ~ilicone resins produced by prior art methods. Th~
two resins are sirnplr dissolved in a hydrocarbon solvent, and I the solvent i:3 stripped off to yield the desired solventless silicone ¦ xesin at 100% solids and havîng a visc osity within the range set I forth hereinabove. Such solventless silicone resin systems can be I utilized in the applications as stated previously without necessitating ¦ the use of organic solvents. However, in at least the case of 1~ the production of a silanol containing silicone resin of the prior ¦ art, such resin does involve the use o organic soIve~ts in :
the process for producing it.

.~ I Descliption of the Preferred Embodiment The reactants for producing the silicone resins of the ¦ instant case comprise a mixture o organohalosilanes in which in most instances the halo is chlorine. For most practical 25 f purposes, the only type of halosilan-s that are reacted to produce Il - 12-! ,1"~ o ~ l If ~ !

!i silicorle resins are chlorosilanes where the chlorosilanes are com-¦l posed of trifunctional chlorosilanes and difunctional chlorosilanes.
i Accordingly, the organochlorosilanes have the formul.~, ~I Ra S; C19 S l~ where .R is selected from the class cons;sting of monovalent hydrocarbon radicals and halogenated monovalent hydrocarbon radicals, and a i5 a whole number ~;hat is either 1 or 2, such that in the final silicone resin the R to Si ratio in the resin varies from 1. 0 to 1 9:1. More preferably the R substituent groups in the formula of the chlorosilanes above is preferably selected from alkyl radicals such as, methyl, ethyl, propyl; cycloallcyi radicals such as, cyclohexyl, cycloheptyl, and etc.; alkenyl radicals such as vinyl~ allyl; aryl radicals such as phenyl, methylphenyl, ethyl- ¦
phenyl;and fluoroalkyl radicals such as 3, 3, 3 trifluoropropyl. In ~ the mo~t preferred embodiment of the instant case, the R radical ¦ is selected rom alkyl radicals, cycloalkyl radical* alkenyl radicals~ aryl radicals and fluoroalkyl radicals, all such radicals I having up to 8 carbon atorns and mixtures of such radicals. Most ¦ preferably, the R radical is selected from methyl and phenyl and I a is such that the proportionate amount of moDoorgano trichloro i silane and diorganodichlorosilane will be su~icient such as to give - `
¦ the final silicone resin product the desired R to Si ratio that is ~ ;
desired for the particular resin. Such chlorosilanes are well ~ known in the silicone art. Accordingly, to initiate the reaction, ! a mixture of alcohol and water a~e s`imply added to the foregoing ~I chlorosilanes where the alcohol is an aliphatic alcohol of 1 to 3 .. , , ` ~

60SI-171 ' , ~l carbon atoms. Most preferably the alcohol is m~thanol. Although aliphatic alcohols of above 3 carbon atoms may operate in some circ~lmstar~ces, nevertheless, the alko~y groups that they form in , th~ silicone rcsin pxoduct in th~ hydrol~rsi3 mày not be desired in S the s~licone :resins of the in~ant case since at high temperatures, , that is, temperatur~s above 250 C, such higher alkoxy groups j may be unstable. ln additio~, such higher aliphatic alcohols do not T react as readily to produce the alkoxylated silicone resins of the I instant case and do not hydrolyze off as readily.

~Accordingly, the mixture of water and aliphatic alcohol is preferably added to a mi~ture of chlorosilanes such as, pex part of organochlorosilanes there is utilized from . 05 to 0. 2 part of water and from 0.1 to 1 pa~t o the aliphatic alcohol. Most preferably I there is utilized from . 05 to 0. 5 parts of watex and 0.1 to 0. 4 partls ¦ of the aliphatic alcohol per part of organochlorosilane. Such a~nounlts of alcohol and water are not necessarily critical. There must be I suf~icient water added such that the water will allow some of the ¦ chlorine groups in the silane to hydroly~e to be replaced by alkoxy ¦ groups from the alcohol and to allow some cross-hnking of the j chlorosilanes to ~orrn the silicone xesin alkoxylate. It i6 importantl 3 that too much water not be present in this initial hydrolysis reaction ¦i since ;f too much water is present then a small amount of alkoxy groups is formed and there will be formed silanol groups and J s;loxy crosslinking bridges between the silane monomer fox~ning a ¦

I high visco~ity silicone resin.

l l . .

Accordingly, most preferably there is utilized from . 05 to 0. 2 parts of water per part of chlorosilanes such that the appropriate amount of alkoxy groups are ormed in the silicone resin alkoxylate I and such that the chlorosilanes are not overly hydrolyæed. In such S a hydrolysis-allcoxylation procedure, it i3 desired to add the xnixture of alcohol and water to the chlorosilanes so as to maintain the te.m.peratuse of reaction at room. ternperature or below. With auch addition procedure at room. temperature, the reaction .
temperatur~ will first go below room ternpera1:ure and then slowly reach room temperature toward the end of the hydrolysis~alkoxylation.
Accordingly, for m.ost purposes, it is desired to add the mixture of alcohol and H~0 to the chlorosilanes. Such addition step can take place in any amount of time but it most preferably takes place in a period of tim.e from 0. 5 to 2 hours and most preferably from. Of !; to 1-1/2 hours. The mixture should be agitated during the addition of the alcohol and water to the chlorosilanes. ~fter the addition of the alcohol and water to the chlorosilanes in which the hydrolysis~
alkoxylation iæ completed, it is then necessary to reduce the acidity ¦ ~
content of the silicone resin alkoxylate that is formed. The reason I ~.
for this i8 that if the acidity of the silicone slkoxylate is much above l -! 100 part~ per million then the acid content in the silicone alko~ylate , -will, when the water is added in the subsequent hydrolysis step i as will be discloæed below, Gatalyze the condensation of silanol and alkoxy groupe resul:ting in a formation of a silicone resin of high , viscosity as the silicone resin product which is undesired in I accordance with the present invention.
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~. 60 SI 171 ~l~L 3 ~ 9 The acid/water and methanol and the silicone resin alkoxylate, ¦~ is then heated at a temperature in the range of hO to 80C so as to drive off hydrogen chloride acid that is formed during the hydrolysis.' I At any rate, it i9 desired to heat the silicone alkoxylate in the foregoing temFe rature ran~e to dri~e off as rnuch hydrogen chloride as is possible. At the end of this step there results a silicone alkoxylate having an alko~fy content of anywhere from 5 to 40% by weight with a hydro~en chloride content of anywhere from 0. 5 to ji Z~O by weight Accordingly9 it is still desirable at this point to reduce the acidity o the silicone allcoxylate To accomplish this there is added to said silicone alkoxylate of anywhere from 0.1 to Z parts of an aliphatic alcohol and preerably an aliphatic alcohol of 1 to 3 ¦
carbon atoms such as, methanol, per part o the silicone alkoxylate.
l S ¦ The alcohol is mixed with the silicone alkoxylate and then i~ 3 desirably distilled o:Ef at t0mperatures in the range of 80 to 100C i either under atmospheric pressure or sub-atmospheric pr essure to remove the aloohol and strip oi~E, along w*h the alcohol, the hydrogen ehloride in th0 silicone alkoxylate. This step may be repeated any number of times until the acidity of the alkoxylate-is below 1000 parts per million. The addition of ~e methanol is ¦ repeated asmany times as is necessary to bring the acidity of the I s;licone alkoxylate to the foregoing levels.
t Accordingly, at this point it is still desirable to reduce the ¦ acidiky of the silicone alkoxylate to 100 parts per million or less. ¦
I In order to accomplish this the necessary amount of alkali metal ¦¦ hydroxide and most preferably, potassium hydroxide or sodium hydroxide is added to the alkoxylate BO as to reduce the acidity to 100 parts per xnillion or less.

¦l It should be noted that an alkali metal hydroxide wa i not used ¦~ in the initial reduction of acidity since it is highly undesirable to have a large an~ount o alkali rnetal salts in the alkoxylate and ', I in the final silicone resin product since such will, in some instances I detract from the electrical properties of the silicone resin product. i I Accordingly, after the alkali metal hydroxide has been added there i I is obtained a silicolle resin alkoxylate with an acid content that does~
not exceed lO0 parts per million and preferably does not exceed 50!
parts per million. At this instance then the silicone alkoxylate ¦ ~ t may then be hydrol~zed. It is this hydrolysis step which is critica in the process o~ the instant case. The function of the hydrolysis step is to substitute some alkoxy groups with silanol groups in the i2ilicone resin alkoxylate to produce a silicone resin having the viscosities discussed previously. If too much water is added, then too many of the alkoxlr groups will be removed, the silicone resin ¦
will become too highly crosslinked resulting in a silicone resin with~
unacceptable high viscosity. If too little water is utilized in the hydrolysis, then sufficient silanol groups will not be imparted to the silicone reL2in product such that it will be able to cure as desired with most known catalysts. Accordingly, there is desirably added I - -to the s iliccine alkoxylate of the instant case and having the acldity ~ discussed previously, from generally 0. 2 to 0. 8 moles of water per ! mole of alkoxy group in the silicone reiin alkoxylate and more ; preferably from 0. 3 to 0. 8 moles of water per mole of alkoxy ~
¦ groups in the silicone resin alkoxylate. ¦ -! It should be noted that for this addition of water in this step ~
which iB criti al, it ie neceseary to measure the alko y content of i ~~' l l 1 -17- l 39 6 0SI 17 l ¦, the silicone alkoxylate so that the desired amount of water can be i ¦! added, A s,ilicone resin of the viscosities discussed previously Il will not be obtained unless the oregoing arnounts of water are added ¦, a~ set orth above, The addition is preferably carried out at room S j ternperature to the reflux temperature of the system which is about 7S C, The water may be added with good agitation to the silicone j alkoxylate and allowed to react in a ieriod of time o anywhere I
rom 0. 5 to 3 hours in a one-step addition. However, n~ost prefer .
ably the wate~ is added in two or more increments such as four .
increments over a period of time varying from 1 to 3 hours with good agitation so as to allow the water to properly mix into the silicone alkoxylate and fully react, i It is desirable in this final hydrolysis reaction that most, ¦ , if not all, of the water react to replace the alkoxy groups in the desired amount so as to produce the silicone resin product of the ¦ ,, instant case having the proper amount of alkoxy groups and having the desired viscosity properties, It is irnportant that alnlost all I of the water that is added react with the silicone resin alkoxylate ¦ Yince that will impart to the silicone resin the de~ired crosslinked ¦ resinous structure, Accordingly, to facilitate such compIete reaction I a~d in addition to the incremental add;tion of water that is I i -i recommended above, there may be utilized as a solvent the foregoing ¦.:
J aliphatic alcohols of 1 to 3 carbon atoms and most preferably I methanol, In order to facilitate the foregoing reaction there may be i added anywhere from 0,1 to 2 parts per part of the alkoxylate o the~
i~ aliphatic alcohol to the s,ilicone allcoxylate The water and alcohol i ¦I can be mixed~ the alcohol solubilizing the~ silicone alkoxylate and wa~er j 11 - 18 - ~ :

60SI~ 1 71 ¦l so that the hydrolysis reaction with the water takes place more ¦1 rapidly and rnore fully. It may be noted that addition~l alcohol i6 generated during the hydrolysis reaction. After the necessary per;od of time, as speciied above, of 0. 5 to 3 hours and more preferably from 1 to 3 hours there xesults a silicone resin product of the installt case with some .methanol and possibly very small amounts of water being present. Such m.ethanol and water can then ¦ ~
be ætripped off at temperatures in the range of 80 to lOODC at :' atmDspheric pressure or sub-st.mospheric pressure to yield the desired silicone resin product o the instant case at lOO~o solids having a viscosity varying from. 200 to 5, 000 centipoise at 25C, and m.ore preferably having a viscosity varying from. 500 to 2, 000 .
centipoisc at 25C.
It should be noted that the acid content of the silicone resin alkoxylate of the instant case is quite important in that in the I .:
hydrolysis step the acid content o the silicone resin alkoxylate ahould i .
not exceed 100 parts per million,. but more preferably does not exceed 50 parts pex million and most preferably does not exceed 15 parts per million. Accordingly, with the above process there is 1 -obtained a silicone resin with an R to Si ratio whexe R was as pre- ¦
viouely def;ned in which ths R to Si varies from. 1. 0 to 1, 9:1, the resin I
has a silallol content that varies anywhere from. 1 to 5% by weight and I ~.
an alkoxy content that varies anywhere from. 7 to 14% by weight and more preferably varies anywhere from. 7 to 12% by weight. This silicone resin is the desired s:ilicona resin of the instant invention.
Such a silicone resin may be utilized at 100% solids as such and may be utilized to form. a coating which may be cured by the well known catalysts utilized for silicone resins, that is, metal ,: . ' .' 1'.

60SI-~71 "

¦ salts of a carboxylic acid. Acco:rdingly, to cure such a siliconer~sin there may be added to i~ a curing catalyst at a concentrati~n of . 05 to 0. 5% of metal by weight of the resirl o a metal salt of a carbo~ylie acid where the ~Qetal is selectecl rom. the class varying rom. manganese to z~lc in the Periodic Table with the exception ' ;
o iron and heating the mixture at a temperature of above 150C, and more preferably at Z50C. The best cure takes place upon heating of the resin at a temperature of 200 or 250C. The metal salts of iron are not preferl:ed as a catalyst with the resins o:~ the instant caæe sinee it has been ~ound that although when utilized as catalysts they result in a silicone film of excellent hardness and of excellent cure, such a cured ilm. does not have good heat stability at temperatures of 250C or above. .
Accordingly, iron salts of carboxylic acids are not preferred ¦ as catalysts for the sillcone resins of the instant case unless such I ' silicone resin coatings that are form.ed are to be utlllzed or exposed at: temperatures below 250C. It has been found, however, that t~e silicone resins of the instant case can be cured with iron salts of f -carboxylic acids to fol m coatings of excellent hardness and c>f some ¦
- measure of thermal stability at temperatures of 250C or above by ';~
utilizing as a catalyst from. . 005% by weight or less o:f iron as the ¦ iron 6alt of a carboxylic acid based on the weight of the total silicone acid composi~ion, in combination wi~h . 05 to 0. 5% by weig~ht o~ another metal as the metal 6alt of carboxylic acid, that is, metals varying from manganese to zinc irl the Periodic Table I . i - 20- ~
., . .

60SI~171 3~
i' .
such as, for instance, zinc octoate.
. The most preferred catalysts for utilization with the silicone ¦I resin of the instarlt case and in which cure can take place at ' temperatures above l S0~ C and more preferably at temperahlres ~ above 200 or ~50 C in which the cured silicone resin coating has good hardne3s as well as good thermc 1 stability at temperatures of 250 C or above, are zinc salts and manganese salts of carboxylic acids~ such as zinc octoate or manganese octoate. .However, even though the abo~re catalysts axe suitable with the silicolle resins of .
the instant case in producing silicone resin coatings of good hard-ness and excellent thermal stabllity, they have one disadvantage, that is they normally do not start the cure of the silicone resin until the temperature of normally above 200 C or 250 C is reached.
Accordingly, during sucll heating step a certain amount of the volatiles in the silicone resin will be volatilized beore cure of the I, silicone resin takes place, thus, resulting in loss of silicone resin product. Accordingly, it is highly desirable to have a catalyst system for such silicone resins which initiates the cure of the ¦ -¦ silicone resin at temperatures lower than 250 or 200~C. I
I Accordingly, there is also a third type of a catalyst system I -disclosed for the silicone resins of the instant case which is composed of from 0. 5 to 4. 0% by weight of the total composition o the cataly~t ¦ which i8 the combination of 25 to 75% by weight of a metal salt of . a caxboxylic acid, the mctal being selected fro~ the class con-¦I sisting of metals varying from manganese to zinc in the Periodic I
I Table with the exception of iron and :ro~ 25% to 75~0 by'welght of ¦

I l.t ! I .~
I I''`
~ 21- i `

j an amine functional silane, Generally, when both types of catalyst systems are considered, the catalyst can be used at a concentra-11 tion of anywhere from 0. 5 to 4% by wèight o metal and aminoxy 1 silan~ bascd on the silicone res;n. The mixture is then hcated at ~ tempoxature~3 above 100 C, and more desil~ably in the range of 140 to 180C to ef~ect the cure of the siliconè resin to form a ¦ silicone coating of good hardness and good thermal stability at ¦ temperatures of 250 C or ab~ve.

I As noted previously in this additional catalyst systern, it is not de.sired that iron salts of carboxylic acids be utilized in the catalyst system or the reasons given before. With respect to theamine functional silanes, such amine functional silanes can be any type o amine unctional silarles but are more preferably selected I from amine alkylene silanes in which the alkylene group is arly-where from 2 to 8 carbon atoms long. The most preferred amine functional silanes are the gamma-aminopropyltriethoxysilanes and mixtures o such propyl amino silanes which are well lcnown in the I! art. The foregoing metal salt of a carboxylic acid may be mixed -Ii with the amine functional silane in the desired proportions, ~I The most preferred range for amine functional silanes to il metal salt o~ carboxylic acid being in the 22-75 by weight concen-¦, tration so that the catalyst system is composed of 25% by weight of the amine functional silane and 75% by weight of the metal salt of a carboxylic acid. Utilizing such a catalyst syste~n the cure is ~

25 ' initiated at temperatures of as low as 125 C and is completed at I -. .' ' i j'l temperatures of 180C or in the range of 160 to 200C, thus ?~ rninirnizing the escape of volatiles from the silicone resin product ¦

¦¦ ?~

,! o the instant invention prior to cure. Accordingly, in such a il catalyst system not only is good hardness and good thermal stabilit~f ~ obtained from the silicone coating that is ormed but cure is initiat~d `' 5 ~1 at ternperatures a8 low as lZS C, thus minimizing the loss of volatiles flom the silicone resin product. I`he only disadvantage with such a curing catalyst system is that it has a short shelf life. The system must be used within Z4 hours after the aminoxy ¦-functional silane has been added to the mixture. Such a curing I
; catalyst system o~ers the advantages of low 105s of volatiles, that I is, the ad~rantage of the SIH olefin platinum cataly~ed silicone resin .

. I 1 gystems o the prior art that was discussed p.reviously without incurring as much an expense in production of the system as is the ~I case with the system of the prior art that was discussed previously :

: ' ~ The silicone resins of the instant case have many uses, but ¦

15 1l the two most prominent uses for such silicone resins are that they ¦

¦I can be utili~ed in the formation of silicone paints and silicone !
~I varnishes and similar types of coating syst0ms. In the p:roduction .
¦¦ of silicone paints the silicone resin of the above case is used at i il 100% solids with a pigment where there is present from . OS to ~! 0. 5% of the total compositi~ of one of the curing catalysts discu~s 1:

,) ed previously and other normal ingredients utilized in such silicone i resin paint systems. The resulting silicone paint may then be - applied to the substrate and cured at elevated temperature s to ormt a hard silicone paint coating which has thermal stability as high as ,' 250 C or above. The silicone resins of the instant case can also ~i i~ be utilized to produce silicone varnishes which is accomplished by - ~' talcing the resin at 100% solids where there is present fxom 0. 05 tc 'I 60SI~171 ¦1 0. 5% by w~ight of the resin, the curing catalysts disclosed pre-viously, and c~ing by simply h~3ating the coated surface at . tcmp~rature~t of 200 - 250C, resull:ing in a cured silicone varnish ~ coating in a period o tirne varying anywhere from. 30 to 60 minutes.
¦ But osE.7ecially the silicone resin of the instant case may be utilized ! at 100% solids in forming various silicone coatings on various sub-il strates with or without the use of primers and with the above curing ¦¦ catalyst svstem.s to form silicone coatings for the usual electrical ~¦ ineulative applications.
i~ The silicone resin o the instant case may also be approxi- .
, mately duplicated by ~:nixing or preparing a mixt~lre of a high silanol silicone resin disclosed by the prior art and a high alkoæ~r . .
containing resin as taught by th~ prior art. ~ccordingly, in l another le~s preferred embodiment of the instant case, there ;8 ! provided a solventless silicone resin system having a viscosity at 100% solids ~arying from 200 to 5, 000 centipoise at 25C, comprising (a) from 50 to lSyo by weight o~ a irst silicone resin when said resin is com.posed o~ organo trifunctional siloxy ~nits and diorgano . -trifunctional silox~ units where the organo to Si ratio varies from ! 1 0 to 1. 9~1 and a hydrocarbonoxy content that varies rom 10 to 25%
~! by weight and a silanol content that is les6 than 1% and (b) fronn 50 to 85% by weight of a second silicone resin composed of mionoorgano ` trifunctional silo~r units and diorganodifunctional siloxy units where 'I the organo to Si ratio varies from 1. 0 to 1. 9:1 having a hydro-~I carbonoxy content that varies from 0 to 4% by weig~t and a I

1' silanol conten~t that varies from 3 to 8% by weight whe~e the organo ¦I groups in said resin are selected from. ~he class consisting of alkyl¦¦ radicals, cycloalkyl radicals, alkenyl radicals, aryl radicals and fluoroallcyl radicals, all having up to 8 caxbon atom.s and mix~ures thereof. In short, the organo substituent groups in such prior art silicon~ resins which orrns the ~ni~ure can be selected from any of the monovalent hydrocarbon raclicals and halogenated mono- ¦
valent hydrocarbon radicals defined previously, and for the organo substituent groups of the preferred silicone resin of the instant case.
The silicone resin is produced by dissolving the second . silicone resin in a hydrocarbon solvent, the second silicone resin beîng a solid at room. temperature, to form a solution if the resin .
is not in solution already, mi~ing in the first said silicone resin in said solution and ater mixing, stripping off the hydrocarbon solvent at elevated temperatures to leave behind a solventless resin system.
Any well known hydrocarbon sol~ent can be utilized. Examples of .
such solvents that may be utilized a.re, for instance, æylene, toluene, . benzene, cyclohexane, cycloheptane, chlorinated hydrocaxbon sol-vents and etc.
The irst silicone resin that was discussed previously is a highly m.ethoxyla$ed silicone resin which is a solventless silicone : -resin, that is, it i6 a liquid at room. temperature and has a viscoslt~r of anywhere ~rom 50 to 200 centipoise at 25C. The only reason why the first silicone resin cannot be u~ ed by itself is ¦ ~-that it does not have sufficient silanol groups in the resin l:o cure properly to form a hard silicone resin coating. As such, such silicone resin~ have limited uses except as intermediates. ~ : -., .', -25-., .

60SI~171 1~' s ! The second silicone resin while ha~ing sufficient silanol grou~s to allow curing to a hard coating, nevertheless, has such a high viscosity at rooi~ tempexature at 100% sol;ds that it has to be ' disso~ed in a solvent to be utili~ed.
Accordingly, such second silicone resin, thal: is the silanol resin, is dissolved in a hydrocarbon solvent at anywhere from 5 to 50~o solids then the first silicone resin, that is the high alkoxy resin may be added to a solids concentration of anywhere from 5 to 40% by weight in the solvent. The resulting resins are dissolved and then the hydrocarbon is stripped of under reduced pressure to leave behind a solventless silicone resin system which has proper-ties approæimating the properties of the irst silicone resin of the instan~ case. A high silanol content resin may be obtainecl by a process w011 known in the prior art and comprises usually a proces s o~ agitating a mixture of organohalosilanes where the organohalo- ¦
silanes were as previously defined. The organo substituent group on such organohalosilanes is the same as $hose organo substituent I groups as was previously defined for the radical E~. There is ¦ mixed with such organohalosilanes from about 1. 7 parts to abou$ 10 l 20 ~ parts by weight of water, per part 4f organohalosilane; from about ¦
¦¦ 0.2 to about 0.5 parts of acetone per part of organohalosilane; and ¦I from about 0. 3 to about 5 parts by weight of a water immiscible 11 organic solvent per part of organohalosilane where the organo wate~
!~ immiscible organic solvent may be any water immiscible organic 25 , solvent such as, xylene, toluene and etc., and from 0 to about 1 ~ mole of an aJ.iphatic alcohol having rom I to 8 caxbon atoms per i ' .' I
~1 -26- !

~1~ 3~3~ -mole of halogen attached to the silicon of the organohalosilane.
Then there is separated the oxganic solvent solution of a silanol ,l containing polydiorganosiloxane having an average ratio from 1 to organo radicals per silicor ator~ from said hydrolysis mixture.
The xesulting silicoIle resin hydrolyzate that is obtained from such ' hyd:rolysis procedure is sirnply washed with water until the acidity I
is reduced to the desired level that is below lO0 parts per million and more preferably below 50 parts and most preferably below 15 parts per million. Such reduction of acidity is carried out by decantation of the acid/ ~vater mixture and also by stripping off the hydrogen chloride gas initia~ly formed in well known stripping procedures results in the high silanol content silicone resin.
It should be noted that the halo in such organohalosilane reactant is most preferably chlorine. The organohalosilane mix- I
¦ ture may be any organohalosilane mixture and is preferably selected from an organotrichLorosilane, or a mixtuxe of organotrichlorosilanT
and dioxganodichlorosilane, or a reaction product of an aliphatic monohydric alcohol having from 1 to 8 carbon atoms and a mi~ture j of organotrichlorosilanes and dlorganodichloroeilanes, and the m~x- ¦
ture of such a reaction product and with the mi~ture o:E organotri-chlorosilane and diorganodichlorosilane wherein the foregoing organ~
groups are the same as given previously for the R radical defined i for the chlorosilanes utilized to produce the preferred silicone resi I¦ pr oduct of the instant case.
2S I Utilizing such a procedure there is obtained a high silanol content resin in which the organo to Si ratio may vary anywhere 3~

from 1.0 to 1.9:1 and most preferably varies from 1.1 to 1.9:1 and having an alkoxy content t.ha-t varies anywhere from 3 to 8~ by weight. The production oE such prior art silicone resins is most fully disclosed in Canadian Patent 868,996, issued April 20, 1971, of Duane F. ~errill. Modifications of t.he foregoing procedure can also be found in the patents of Duane F.
Merril.1, U.S. Patent No. 3,450,672 issued June 17, 1969 and U.S. Patent 3,7~0,527 issued Fe~ruary 5, 1974.
Vari.ations of the above procedures are also known in the art for producing the high silanol content resin and any such procedure can be utilized to produce such a resin. It should be noted -that such resins produced by the utilization of the procedures set forth in the foregoing patents of Duane F. Merrill, results in a silicone resin which is a solid at room temperature.
The high alkoxy resin can also be produced by methods well known in the prior art following the first hydrolysis-alkoxylation step in the foregoing patent of Roedel, U.S. Patent 3,846,358. This resin is simply produced as recited in the patent by contacting a mixture of organotrihalosilanes and diorganodihalosilanes (where the halogen is chlorine and where the organo groups are the same as the R radicals defined above for the`procedure for producing the perferred silicone resin of the instant case), with from about 0O5 to 1 part of water per part of organo-chlorosilane and with from 0.1 to 1 part of an aliphatic alcohol having from 1 to 8 carbon atoms forming an , 60Si_171 ~! alkoxyl~ted organosils:~ane hydroly~ate having from. 5 to 40% by Il weight of the alko~y groups.
¦I The rest of the steps of the E~oedel patented process are ¦ not followed except for docreasîng the acid content. ~ccordingly, S the silicone resin alkoxylate obtained from. this first step of thefo:regoing :Roedel '358 patent is is01ated by removing or by stripping the methanol of:~ at elevated teTn.pexatures. The acid content is decreased by washing the hydrolyzate with an aliphatic alcohol, pre-erably methanol, and then removing aliphatic alcohol by stripping until the acid content does not e~ceed 1000 parts per million. Then finally the acid conte~ is further reduced such that it does not exceed 50 parts per million and more preferably does not exceed lS parts per million by adding an allcali m.etal hydroxide to the silicone resin so a~ to decrease the acid content to the desired level. As stated previously, any excess m.ethanol that has been added during the washing steps is removed by stripping at elevated temperatures o:~ 150-160C either at atm.ospheric pressure or at sub-atrnospheric pressure. A~ a result o~ this procedure there re~ults a silicone resin having hydrocarbonoxy content or a~coxy ¦ content var~ing anywhere rom ~ to 40% by weight and more ;
¦ preferably for u6e.in the instant process from 10 to 40% by weight, .~ ¦ and a silanol content that is up to 0. 5% by weight. ¦
- ~ It should be noted that although trace6 of silanol may be I present such silicone resins stilldonothavea sufficientlyhigh 1 silanol cont~nt to cure properly with m.ost of the :
.

. - 29-~ 60 SI 171 3~

1~ known metal salts of carboxsrlic acid catalyst.
¦¦ The process for producin,g the high alkoxylated silicone ¦I resin of the prior art is basically the first step in the process o the ¦I foregoing Roedel, USP 3, 846, 3S8, followed by acid reduction and isolation of the silicone resin, It should be noted that if a sub-sequent hydrolysis step of the Roedel patents is carried out that there is obtained a solid as the silicone resin product. Such a material is unsuitable for forming the silicone resin blends of the instant case. However~ utilizing this procedure th,_re is obtained a highly alkoxylated silicone resin having a m.ethoxy content varying anywhere from. 5 - lO and more preferably lO - 40%
by weight and a viscosity of anywhere fronm 25 to 200 centipoise at 25C. It should be noted that while such a silicone resin ha~ some uses, nevertheless, it is highly undesirable or directly forming coatings such as electrical protectîve coatings or silicone paint coatings sinee it will not cure properly even with the application of a metal salt of a carboxylic acid and even with the use of heat to cure the resin.
To obtain the solventless silicone resin blend of the less preferred embodiment of the instant case, the high silanol content re~in is simply taken as a solution in a hydrocarbon solvent such as xylene, toluene, benzene, cyclohexane, cycloheptane or the chlorinated hydrocarbon solvents at a solids concentration of any- !
l where from 5 to 50% by weight and the high alko~y content resin is ! then added to the solution and dissolved at a concentration of any-~l where from S to 45% by weight. When the solution is com.plete, then le Il I
. ' I
l - 30-. solvent i3 simply stripped off to give the less preferred solventless silicone resin o the preserlt case.
' The Example~ b~elow are given 'to illustrate the reduction Il to practice of the invention. They are not given to æ,et limits a,o~ to the scope of the inst3nt invcntion. All p3rts are by w~ight.

EXAMP LE I

There was composed a Resin A comprising adding Z400 parts of phenyltrichlorosilan,e, to 830 parts of hexyltrichlorcsilane and there is added to the blend, a blend of 549 parts of methanol and 2',58 pa:rts of water over a period of time of 50 minutes. The pot temperature was 25 C at the beginning, but dropped to 3 C and at the end of the addition was 18C. The mixture was then heate-to refl~lx at 78 C, cooled and then added to it 130 parts of MeOH, stirred for 5 minutes and stripped to 100C at 100 mm~ of ¦ mercury ~ae,uum. The acidity wae 1010 parta per million HCl.
Then there was added to it sufficient amounts of a 30% by weight of KOEI in methanol solution to reduce the acidity to 9 parts per million HGl. The methoxy cox~tent was 18. 9~o by weight.
Then took ,270 parts of the above methoxy1ate and added 75. 5 parts I
I of MeOH and 5. 95 parts of H20 to give a water to methoxy mole , ~ 1 I ratio o O. 2, heated the mi~ture to reflux for 1 hour at 68'~C and i then stripped the mixture to lOO'~C at 100 mm mercury vacuum to 1l ~
¦ yield l~e sin A. ¦ ~ -¦ There was taken 2S0 parts of metho~;ylate intermed;ate ¦¦ above used to form Resin A and adjusted to 12 ppm of HCi. To ' .' I . ..
l - 31-!I this there was added 70 parts of MeOH and 8. 2 parts of ~rater.
¦I The resulting mi~ture was heated to reflux and refluxed for 1 hour at a pot temperature of 68C. The resulting silicone resin and i methanol mixture was then heated to 100C at lOO mm. of vacuum I to strip off ~he methanol. The silicone resirl liquicl was filtered to give the silicone resin product, which i8 Resin B.
There was prepared a Resin C where in the metho~ylate which was utili~ed in the preparation of Resi~ ~ containing 18. 9'~o by weight of methoxy groups was taken, that is, 250 parts of such rnethoxylate was taken and adjùsted to l2 parts per miliion of acidity. There was added to this 70 parts of methanol with 10. 9 part3 of water. The resulting mi~ture was heated to reflux and refluxed for l hour at 70 C. The methanol was then stripped of at 100C and lOO mrn. of mercury vacuum and the silicone resin liquid that wa~ left was filtered to obtain the Resin C product.
There was then prepared a Resin D in accordance with the prior art procedures. Resin D was prepared by taking 74. 3 parts of phenyltrichlorosilane and 2S. 7 parts of he~yltrichlorosilane and adding to this bl~nd 30. 3 parts of methanol and 4 l p~rts of water.
During addition, the temperature dropped and then rose back to room temperature. The resulting mixture was then heated to reflux for 15 minutes at a temperature of 70 - 90C, and cooled to room temperature. Then 4 parts of methanol was added to it and I rnethanol and hydrogen chloride were stripped off by heating the ¦
¦ ~nixture at atmospheric pressure to a temperature of 125 - 130-C. I -II ~t the end of this stripping procedure, there was lOOO to 3000 parts -32- i~

- ; 60SI-171 ?
I per rnillion o HCl in the silicone resin methoxylate. There was ¦¦ then added to the methoxylate 5. 7 partæ of methanol and a 45% .?
¦ ~queous pot~ssium hydroxide solution to reduce the acidity of the 1 silicone ~lkoxylate to 80 to 150 parl:s per mlllion o hydrogen chlori~e.
Thc methoxylate was then heated to reflu~ at a temperature of 70 _ 75~C, and there was added 11 parts of wa,ter in 4 equal increments of 2, 75 parts e~ch allowing 15 minutes reElux between additions.
Then the entire mi~ture was refluxed for an additional 1 ha~ r. At the end of that time, the mixture was stripped to remove methanol and excess water at 9SC at atmospheric pressùre and then the pressure during such stripping procedure was reduced to 100 mm of mercury. At the end of that time there was obtained a highly viscous silicone resin which was dissolved in irst 5. 3 parts of n-butyl acetate and then reduced further in viscosit~ by addition of mineral spiril:s. The final properties as well as the hydrolysis conditions of these silicone resins is given in Table I below, for comparison purposes. It should be noted th~t the viscosities of the resins ~?roduced in accord~nce with the instant process were much lower than the viscosity of the prior art resin - Resin D.

TABLE I

Material Hydrolysis Conditions Product Prope~ties pprn HCl ~2~L~ 'iæc. (cps~ %OH %OMe __ I
Resin D 100 1. 0 Thick semi-3. 5 4. a1. o 2.10 s olid Resin A 9 0. 2 485 1. 9 14.1, j Resin B 12 0. 3 977 1. 5 13. 4i ¦ Resin C 12 0.4 2270 3.1 12.21 -.r? ?~ ?l'~ ?~ ?~ t~ r~ t1~ ?l j i! j}iil3i j 60,SI-171 !
EXAM PLE II

There was prepared a Resin E in accordance with the ¦ process of the instant case, comprising taking 318 parts of ¦ meth~rltrichlorosilane, 795 parts of phenyltricillorosilane, 77~ of dimethyld;chlorosilane, 1113 parts of diphenyldichlorosilane and adding to this blend a blend o~ 479~ parts of methanol and Zl 6 parts of water, which addition took place over an hour. The mixture during such addition dropped from the initial temperature of 25~ C
to -2DC and then rose to 24C by the end of the addition. The resulting mixture was heated to reflux and refluxed for 15 minutes at 68C. Then there was added to it 120 parts of methanol and t~e mixture was stripped at 100 C and 100 n~n. of vacuum . This addition of methanol and stripping was repeated after whish the acidity was reduced to S40 parts of HCl. Then the acidity of the mi~{ture was adjusted to 4 parts per miilion of HCl by adding NaOC~I3 in methanol. This methox~rlate contained 15% by weight of methoxy groups. Then 250 part~ of the methox~late was taken and there was added to it 60 parts of methanol and 12. 2 parts of ~ -water. The rnixture was refluxed for 1 hour at 71 C and methanol wasstripped oi~E at 100C and 100 mm. of vacuum to ~rield the Resin E a~ a product.
¦ Resin F was then prepared. There was then taken 250 ¦ parts of the methoxylate utili~7ed or prepared in accordance with ¦ the procedure or preparing Resin Æ as set forth above and there !
I was added to it 60 parts of rnethanol and 14. 7 parts of water.
.' ,,'' . .
~1 - 34 _ Il I

I The resulting rnixture was heated to reflux for 1 hour at 75C,and ¦ at the end of that t;me the methanol was strippecl off at 100 C
¦ and 100 mm. of mercury vacuum to yield the silicone resin product - Resin F.
Thexe was prepared a R.asin G by taking 250 parts of the metho~ylate produced in accordance with the procedure set orth in the production of Resin E and there was added to such metho~y-late 60 parts of methanol and 17. 2 parts of water. The re~ulting mixture was heated to reflux for 1 hour at a temperature of 72C.
At the end of that time, the rnethanol was stripped off at 100C
temperature and 100 mm. of vacuum.
There was prepared a Resin H. Such procedure comprised taking 236 parts of methyltrichlorosilane, 66S parts of phenyltri-chlorosilane, 203 parts of dimethyldichloxosilane, 398 parts of diphenyldichlorosilane and adding to such chlorosilanes a blend of Z31 parts of methanol and 119 parts of water over a 42 rninute I -period. During such addition the pot temperature dropped from 25C to -20C and then rose to Z30C The resulting mi~ture was heated to reflux for 15 minutes at a ternperature of 67 C. The~
there was added to it 60 parts of methanol and the methanol and HCl was stripped off at a temperature of 100 C and 100 mm. of mercury vacuum. Another 60 parts of methanol was added and upon stripping to 1û0C at 100 mm. the acidity was xeduced to ~ 419 parts per million of HCl. Addition of a third portion of 25 j methanol and strippin~ reduced the acidity to 83 parts per million j of HCl. There was then added to the methoxylate 10 parts of ; 60 SI 171 ¦I calcium carbonate and 60 parts of methanol and the mixture was 1i refl~-Lxed for 15 minutes. There was further added to it 5 parts ~, I of Celite 545 i~nd th~ resultir~g mixture was stripped at 100 C
and 100 mm. o mercury vacuum, I'he resulting mixture was then, iltexed to remove excesss calcium carbonate and filter aid and there resulted a silicone methoxylate ha~ring 5 parts pcr million of HCl. At the end of this step, 160 parts of the mcthoxylate was j taken which methoxylate contained 17. 5'~o of methoxy groups and there was added to it 36, 6 parts of methanol and 6. 6 parts of water. The resulting mi~tu~e was heated to reflu~ and refluxed for l hour at 70 C. The methanol was then stripped off at 100 C
and 100 mm. of mercury ~acuum to leave behind` the desired product Pcesin H. The hydrolysis conditlons and the product properties o the silicone resins produced in accordance with the procedures above of l?<esins E, F, G, H are set forth in Table II
below. The data in Table II below indicates that there IS obtained the preferred silicone resin of the instant case with the properties discuss~d previously by following the process conditions of the instant case. , Mate~ial Hydrolysis Conditions Product Propert;es ppm HClH20/ OMe Visc. (cps) %OH ~_ Resin E 4 O. 53 370 2. 08. O
I Re sin :F' 4 0. 64 500 2. 7( 8. 3 ¦ Resin G ' 4 0. 75 930 2.17. l ~el:i H 5 0.40 316- 1. 5 10 6 EXAMPLE III

¦I Then samples of Resin F was taken as prepa~red and dis-¦ closed in Exan~ple II and were cured in 1 mil. films with different I metal salts o carboxylic acid as indicated below. The resulting Eilrns wer~ tested for hardness by passing pencils of different hardness over the cured ilm surEace and noting if the pencil scratched the ~urface. Further heat tests were carried out for the resin cured with metal salt of carbo~ylic acid as indicated below for ~iferent times o~ cure. In addition, the hardness of the pencil that did not scratch the surface of the cured coatiTlg that i5 the highest hardness of the pencil that did not scratch the cured coating of the silicoDe resin is indicated in Table III below.
Accordingly, the foregoing tests of Resin F for its cured coating hardness for diferent cur:ing time at a temperature of l S 250 C is indicated in Table III below. .

TABLE III
Cure of Solventless Resin in l-rnil Films Material Metal Octoate Catalyst Pencil EIardness _ As Metal Minutes at 250 C. ¦
2t7 Resin F 15 30 S0 ¦
A 0. 005% Fe HB F
B 0. 500 Zn 5B 2:B B ¦
C 0.1 00 Mn < 6B 4B 3B
D 0.100 Co ~6B 5B 3B
Z5 IIn Table III above the A~ B, C, and D under Material in-, , ~ dicate dif ierent :ar ple: of Re:in F that were te:ted with the ~' 60 SI 171 3~

¦ different rnetal salts of carboxylic acids as indicated in the Table.
In addition to the above tests, Samples of Resin F were tested again being cured by different metal salts of carbo~ylic ~cids as indicated in Table IV belo~v wherein the samples were cured at a temperat~lre of 250 C for periods of time varying from 30 - 60 minutes to 24 hours and the hardness of the surface again was determined by the pencil test. In addition, s~ch cured samples were then maintained at 250C after the hardness test to determine how long they could be kept at that temperature before cracking.
l 0 Accordingly, the data on Table IV below indicate s also this information giving as sueh the thermal stability of the sillcone resi~
coa~ing ormed from Resin F as cured by difYerent cur~ng catalysts The data that was obtained from such tests is as follows:

TAB LE IV
Thermal Stability of l-mil .Film of Sol~entless :Resin Metal Octoate Pencil Hardness Hours Crack Catalyst Time at 250 C. free tirne at Material as Metal _ 250 C
30 min. 60 min. 24hrs.
2 0 R e sin A 0. 005% Ee F F H 2~
B 0. 500 Zn 2B B 2H ~240~3H) C 0.100 Mn 4B 3B H ~240~2H) D 0. 100 Co 5B 5B HB ~240(3El) EXAMPLE IV
This E~ample illustrates the ormation of the less p:referred alternate embodiment of the instant case wherein the solventless i silicone resins are formed by mixing high silanol content resins ¦
with high alkoxy content resins.

t ~ 7it ~ J ~ ~". ' I It'~ ' t 6û SI 171 LfV~

Accordingly, there was prepared a Resin K eomprising takin~
159 parts of methyltrichlorosilane, 398 parts of phenyltrichlorosilane, 387 parts of dimethyldichlorosilane and 557 parts of diphenyldichloro-~ silane ~hich was added to 1350 parts of toluene and 1350 parts of !
acetone, and ~500 pa:rts of water. The c~ddition toolc placc over 7S minutes and the resin-solvent phase was separated after the hydroly~ate mi~ture had been allowed to settle for 30 minutes. To the resin pha~e there was added ~5 parts of water and the mixture stripped at atmospheric pressure to at 150C to yleld a silicone resin solution in toluene having a solids content o 80.7% by weight ¦
and an acidity of 26 parts per million of HCl. To the resin soluti n was added 150 parts toluene and 30 parts of water and the solution again stripped at atmospheric pressure to 150 C to yield a resin solution in toluene of 83.1% solids and an acidity o 17 parts per lS million HC l. Utilizing such a procedure there was obtained Resm Then there was obtained a Resin J which was obtained by utili~ing the same concentration of ingredients and same procedure I ¦-as set forth for Resin K except the resin was obtained at 84. 2%
solids in toluene and having acidity o 2S parts per rnillion of HCl.
Resin J represents another batch of Resin K.
Then there was obtained a Resin L, which was produced by taking 831 parts of phenyltrichlorosilane, 530 parts o dimethyldi~ I
chlorosilane, 111 parts of diphenyl dichlorosilane, and ~9 parts of ¦
trimethylchlorosilane and hydroly~ing the blend in a mixture of 135 ~ i parts of toluene, l 350 parts o acetone and 4500 parts of water. I
The entire addition took place over 35 minutes during which the ¦

11l reaction temperature was kept below 45 C. The phase s were allowed to separate. There was added to the silicone hydrolyzate 45 parts of water and water and solvent were stripped off to 100 C
¦¦ at atmospheric pressure. There results a silanol containing resin 1 dissolved in toluene containing 38. 6~to solicls ancl 11 parts per million of acîd. The silanol content of the sil;cone resin was 7. 5%' by weight.
The foregoing resins K,J and Lwere then blended with a Resin N and stripped of solvent to obtain the solventless silicone resin 1() system of the instant case, as was discussed previously. Resin N
was obtained by taking a blend of 62. 2 parts of phenyltrichlorosilanl .
29~, 2 parts of dimethyldichlorosilane and 13. 6 parts oE diphenyldi chlorosilane and adding to it a blend of 1 7.1 parts of methanol and 7. 5 parts of water. The addition was over a 1 _ 2 hour period l 5 and methanol and water was added to the silanes. The resulting mixture was then heated to reElu~ for lS minutes. To this was -added 1 3.1 parts o wash methanol, the mixture agitated or lO
minutes to 15 minutes and then allowecl to settle for 20 _ 30 minutesr The methanol-HCl layer was then decanted off and there was added to the silicone alkoxylate layer 0. 5 parts of calcium carbonate and 0. 8 parts of Celite 545. The resulting mixture was stirred for 10 minutes and then stripped to 160C at 100 mm. mercpry pressure. The silicone methoxylate resin remaining was ~hen I ¦
filtered to yield a silicone resin having a ~riscosity of 30 70 centipoise at 25C and a metho~y content of 18. 5 percent by weight., The foregoing high methoxy silicone resin, P~esin N was the mixed in various amounts with the high silanol 11 ~

~1 _40_ ~
Il .

contcnt resins K, J an~ L, ~hos~ plfparation was d;sclosed pre-viously, ancl solvent ~ernov~sd by stri~?ping to produce a low viscosity solventless silicon~l resin ~ysteln having a viscos¦ty in the range of 200 to 5, 000 ce~tipoisc at 25C which could be cured to procluce silicone resin coatings. 'I'hese solventless silicone l~esins were pr~parecl by simply adding the high methoxy;
resln to the solvent solution o the h;gh Yilanol content resins an ~tripping of the solvent. Properties o ~uch individual silicone resins as that dlscussed abov~e, as well a~3 the properties of the final solventless silicone resin blend are set forth in Table Y
below.
T~ABLE V
lends of EIydrolyza e R_s - Metho~y Reactive Resins Hydrolyzate Methoxy l~ole Wt. Visc.
15Resin (H) Resin (l~t) Ratio Ratio cp~.
l~esin Blend Resin % OH Resin ~oOMe OHl OMe EI/ M ~;ardner) . ... ... . _ . .. .... . . .. ... ~ __ .. .
S K 6.9 N 18.5 0.98 60/~0 V l/2 1977) T K " N " l.66 71/29 Y l/2 .
(~Ol 5 U K " N ~' 2. 73 80/20 Z 3 (4630) V J 5.8 N ~ l.34 70l30 Z l/4 (2378) W L7. 5 N " 2. 22 75/ 25 Z
. (2270) X L " N ~ 1. 50 67/33 W
(1070) The above data indicate that a ~olventless silicone resin system can be obtained by the blending in the appropriate amounts ¦¦ the proper types o prio~ art silicone resins to produce a solventlesl !I silicone resin system having the desi:red viscosity and which produces coating~;with desirable properties.

Claims (17)

The embodiments of the invention in which an exclu-sive property or privilege is claimed are defined as follows:

1. A process for producing a solventless silicone resin having a viscosity at 100% solids varying from 200 to 5,000 centi-poise at 25°C comprising (a) adding to organo chlorosilanes of the formula, Ra Si Cl 4-a where R is selected from the class consisting of alkyl radicals, cycloalkyl radicals, alkenyl radicals, aryl radicals and fluoroalkyl radicals all having up to 8 carbon atoms and mixtures thereof where a is lor 2, from 0.05 to 0.2 part of water and from 0.1 to 1 part of an aliphatic alcohol of up to 3 carbon atoms per pa rt of organochlorosilane to form a silicone alkoxylate; (b) heating the alkoxylate to reflux (c) inserting additional amounts of said aliphatic alcohol to said alkoxylate and removing said alcohol until the acid -content of said alkoxylate is below 1000 parts per million; (d) adding an alkali metal hydroxide to said alkoxylate until its acid content does not exceed 100 parts per million (e) adding water to said alkoxylate such that the amount of water that is added is from 0.2 to 0.8 moles of water per mole of hydrocarbonoxy radicals in said alkoxylate; and (f) heating said alkoxylate so as to effect the hydrolysis reaction with the additional water to obtain the desired resin product.

2. The process of Claim 1 wherein after step (a), the alkoxylate is heated to a temperature in the range of 60° to 80°C
to drive off HCl prior to step (c).

3. The process if Claim 1 wherein in step (c) there is added from 0.1 to 2 parts of the aliphatic alcohol per part of said alkoxylate and wherein said alkoxylate and alcohol mixture is heated to a range of 80° C to 100° C to strip off the alcohol and HCl wherein the step is repeated until the acid content is below 1000 parts per million.

4. The process of Claim 3 wherein the aliphatic alcohol has the formula, R' OH
where R' is selected from the class consisting of alkyl radicals of 1 to 3 carbon atoms.

5. The process of Claim 4 wherein the aliphatic alcohol is methanol and the alkali metal hydroxide is potassium hydroxide.

6. The process of Claim S wherein after the potassium hydroxide is added, the acid content of the mthoxylate does not exceed 100 parts per million.

7. Tha process of Claim 1 wherein in the step (e) the wate is added in increments over a period of time varying from 0, 5 to 3 hours.

8. The process of Claim 5 wherein the potassium hydroxide is added as a solution in said methanol.

9. The process of Claim 7 wherein methanol is added along with the water in step (e) 30 as to solubilize the water into the alkoxylate and wherein in step (f) said methanol is stripped off to leave behind the silicone resin at 100% solids.

10. The silicone resin product by the process of claim 1 wherein said resin has an R to Si ratio that varies from 1.0 to 1.9 to 1, a silanol content that varies from 0 to 4% by weight and a hydrocarbonoxy content that varies from 7 to 14% by weight.

11. The silicone resin produced by the process of claim 1 wherein the said resin has a R to Si ratio that varies from 1.0 to 1.9 to 1, and a viscosity at 100% which varies from 5000 to 2,000 centipoise at 25°C.

12. The process of claim 1 wherein said resin is cured by adding to it from 0.05 to 0.5% of metal by weight of the total composition of a catalyst which is a metal salt of a carboxylic acid selected from the class consisting of metals ranging from manganese to zinc in the Periodic Table with the exception of iron and heating the mixture at a temperature above 200°C.

13. The process of claim 12 wherein said resin is cured by adding to it in addition to the metal salt catalysts the iron salt of a carboxylic acid at a concentration of from 0.005% iron or less by weight of the total composition.

14. The process of claim 1 wherein said resin is cured by adding toit from 0.5 to 4.0% by weight of the total composition of a catalyst which is the combination of 25 to 75%
by weight of the metal salt of a carboxylic acid the metal ion being selected from the class consisting of metals ranging from manganese to zinc in the Periodic Tahle with the exception of iron and 25 to 75% by weight of an amine functional silane, and heating the mixture at a temperature above 100°C.

15. The process of claim 14 wherein the amine functional silane is gamma aminopropyltriethoxy silane.

16. A silicone paint containing the silicone resin of claim 1 wherein in said silicone paint there is present at 100%
solids the silicone resin of claim 1 and from 0.05 to 4.0% by weight of the silicone resin of a curing catalyst selected from the class consisting of metal salts of carboxylic acids where the metal ion varies from manganese to zinc in the Periodic Table with the exception of iron and amine functional silanes and mixtures thereof.

17. A silicone varnish containing the silicone resin of claim 1 wherein in said silicone varnish there is present said silicone resin at a concentration of 100% solids and from 0.05 to 4.0% by weight of the silicone resin of a curing catalyst selected from the class consisting of metal salts of carboxylic acid where the metal ions vary from manganese to zinc in the Periodic Table with the exception of iron and amino functional silanes and mixtures thereof.