CA1139093A

CA1139093A - Conductive latex compositions, elements and processes

Info

Publication number: CA1139093A
Application number: CA000343457A
Authority: CA
Inventors: Donald A. Upson; David J. Steklenski
Original assignee: Eastman Kodak Co
Current assignee: Eastman Kodak Co
Priority date: 1979-02-16
Filing date: 1980-01-10
Publication date: 1983-01-11
Also published as: JPS55133455A; US4237194A; JPS6366865B2; JPS55133465A

Abstract

CONDUCTIVE LATEX COMPOSITIONS, ELEMENTS AND PROCESSES
Abstract Or the Disclosure A coating composition useful in forming con-ductive layers comprises a latex having water as a con-tinuous phase and, as a dispersed phase, hydrophobic polymer particles having associated therewith a polyani-line salt semiconductor. The coating composition can be coated on a variety of supports to produce conductive elements. The coating compositions are particularly useful in forming antistatic layers for photographic elements or conducting layers for electrophotographic and electrographic elements. Also disclosed is a preferred process for preparing a latex coating composition com-prising the steps Or loading polymer particles with the polyaniline component of the polyaniline acid addition salt semiconductor and then acidifying the latex to form a polyaniline salt coating composition.

Description

COND~CTIVE LATEX COMPOSITIONS, ELEMENTS AND PROCESSES
Background of the Invention , = . _ .
Field of the Invention The present ~nvention relates to new conductive compositions, elements and processes. More specifically, the conductive compositions of the present invention are dispersions of hydrophobic latex polymer particles having associated therewith polyaniline acld addition salt semi-conductors. Processes for making polyaniline salt-containing latices and methods for preparing elementshaving coatings o~ the compositions form other aspects of the present invention.
Description Relevant to the Prior Art The unwanted buildup Or static electricity on an insulating support has been a continuing problem. It ls well-known that a thin conductive layer will prevent static buildup but, while it ls possible to formulate a conductive composition that can be coated on a support, it has been quite difficult to combine these conductlve properties with other desirable physical properties.
The stringent physical and optical requirements for photographic elements make the formulation of suitable antistatic compositions for these elements particularly troublesome. Many conductors are known which can be coated on photographic elements to provide static pro-tection. One particularly useful class of compositions which can be used in photographic elements is a compo-sition containing the polyaniline acid addition salt (hereinafter "polyaniline salt") semiconductor described in US Patent 3,963,498 issued June 15, 1976, to Trevoy.
These semiconductors are formed by the reaction o~ a neutral polyanilineimine (hereinarter "polyaniline~') with an acld. These semiconductors o~er a number of advan-tages when used in antistatic coatings, particularly when used with photo~raphic films. For example, because these materials are electronic conductors as opposed to ionic conductors, their conductivity is relatively independent o~ relative humidity. Thus3 they retain high conductlvit under conditions o~ low humidity where the bulldup of .. . . .. . , . . ._ . . , . . . , . .. .. . . . .. ... _ , . .

unwanted static electricity ls particularly difficult to control. Further, these semiconductors retain their conductivity when coated in a suitable binder and there-~ore can be used in a variety of elements using conven-tional coating techniques. Still another advantage o~these semiconductors is that they are relatively inex-pensive and therefore can bè used on a rela~ively large scale at low cost.
The polyaniline salt semiconductors of Trevoy o~fer a number of advantages; however3 further improve-ments have been sought. While coatings containing a relatively low coverage of these semiconductors are useful in reducing the resistivity of an insulating support to a certain extent, relatively high coverages o~ these semi-conductors, when used in conventional coatln~ composi-tions, are re~uired to achieve su~ficient conductivity to eliminate static problems under severe conditions. For example~ in order to achieve resistivities on the order of 106 ohm/sq, it is necessary to coat the semiconductors o~
Trevoy at coverages greater than about 35 mgfm2. Unror--tunately, these semiconductors are colored and at these coverages impart to the elements on which they are coated an undesirable density. As an illustration, a coating containing 35 mg/m2 of a typical serniconductor disclosed in the Trevoy patentg e.g., N-{~-t(4-methoxyanllino)anl-lino]phenyl}-1,4-benzoquinone imlne ~-toluenesulron~c acid salt, would have a highly desirable conductivlty of about 1.0 x 108 ohm/sq, but would also have an integrated opti-cal density of about 0.025 in the visible portion of the spectrum. If the coverage of the polyaniline salt in ~uch a layer were to be reduced so as to reduce the undesirable optical density, the res1stivity would increase. For certain critical applicatlons such as, ~or example, in the production of transparent photographic materials, it would not be possible to get suf~iciently high conductivity whlle at the same time desirable low optical density. It is readily apparent that improvements in the semiconduc-tive coating compositions would be extremely desirable.

. .

Aside from the optical densit~ problems associated with the semiconductors of Trevoy, these semiconductors are, in general, insoluble in water. This can be undesirable because coating layers onto photographic supports is more sa~elv and economically accomplished if water can be used as the basis for the coating 5 composition. Extensive milling permits dispersions of water-in-soluble semiconductors to be made in the presence of protective colloids such as gelatin. However, milling in this manner is time-consuming and energy-intensive. It would be ~ighly desirable if a suitable method of coating semiconduc-tors from water could be lO devised.
It is known to use latex dispersions as binders for conductive materials. In conventional processes such as those de-scribed in US Patent 4,011,176, the antistatic materials, such as semiconducting compounds, are simply dispersed in the continuous 15 phase, along with the latex particles. This usually requires ex-tensive mixing and/or milling in order to disperse water-insoluble antistatic material. ~hen this is attempted with polyaniline salt semiconductor antistatic ma-terials, it produces a useful aqueous-based coating composition. However, when the latex is coated and 20 coalesced on a support, high coverages of the polyaniline salt semiconductor are still required to produce the desired high con-ductivity. This high coverage again resul-ts in undesirable density.
While for many reasons semiconductors are highly de-25 sirable in photographic elements, the prior art does not suggesta solution to the difficult problems discussed above. There is no suggestion as to how these semiconductors can be coated from aqueous solutions in order to produce high-conductivity coatings.

30 S mary of the Invention We have found that the above difficult problems can be substantially reduced by preparation o~ a coating composition which uses a polyaniline salt semiconductor, the composition being prepared by particular methods using particular materials.
35 By using the materials and methods described herein, we are able to produce an aqueous-based ~ ~ 3~ 3 coating composition which is capable Or forming coatlngs having, at the same time, high conductivity and low opti-cal denslty. In one aspect of our inventlon, we provide an element comprising a support having thereon a conduc-tive layer, the conductive layer comprising a coalesced,cationically stabilized latex binder and a polyaniline salt semiconductor formed by the reaction o~ a polyaniline and an acid. The lmprovement according to our invention is that the semlconductor and the latex are chosen so that the semiconductor is associated with the latex be~ore coalescing.
The coating composition which forms the layer described above is another important aspect o~ our inven-tion. The coating composition comprises a latex havlng water as a continuous phase and, as a dispersed phase 3 cationically stabilized hydrophoblc polymer particles having associated therewith the semiconductor. The key to the present lnvention is thatg in order to produce layers having high conductivity at low coverage, lt is necessary that the semiconductor be associated with the hydrophobic latex particle in the coatlng composition. By "associated with" we ~ean that the semiconductor is attached to or located within the polymer particle, that ls, the semi-conductor is not merely mlxed or dispersed with the latex dispersion as is known ln the art, but must become a part of the individual polymer particles. Thus, substantially all of the semlconductor in the coating composition must be adsorbed, absorbed or otherwise become an integral part of the polymer particles. By preparing a coating com-position wherein the semiconductor is associated with thelatex particles, we are able to produce coatings having unexpectedly high conductivity at low coverages.
Another aspect o~ our invention is a preferred process ror associating khe semiconductor with the polymer particles in the latex. While other processes can be used, the process of the present invention is particularly pre~erred. The process comprises the steps o~
~ orming a ~olution by d1ssolving a poly-aniline in a water-miscible organlc solYent 7

(2) forming a latex by dispersing cationically stabilized hydrophobic loadable polymer particles in an aqueous continuous phase, (3~ blending the latex with the solution, (4) loading the polymer particles by removing the 5 organic solvent thereby forming a polyaniline-loaded latex, and (5) forming a polyaniline salt-loaded latex by adding sufficient acid to the polyaniline-loaded latex to convert sub-stantially all of the polyaniline-loaded latex to polyaniline salt-loaded latex.
In yet another aspect of the present invention, we pro-vide a process of preparing a conductive element comprising a support having thereon a conductive layer, the process comprising the steps of:
(1) forming the latex coating composition described 15 above, (2) coating the ]atex on a support,

(3) removing the continuous phase of the la-tex and

(4) coalescing the latex so as to form the layer.
Using the coating compositions and processes of our 20 invention, the layers of our invention can be highly conducting while at the same time have very low coverages of the semicon-ductor. This means a savings in materials in the coating process and coatings with very low optical density. These advantages are obtained with coating compositions which can be easily and safely 25 coated because of their aqueous base.
Further, the layers of our invention unexpectedly ex-hibit highly uniform conductivity over the surface of the layer.

D'etailed Descri'ption o'f the Inventio_ According to the present invention, the semiconductor must be associated with the hydrophobic latex particle in the coating composition. Layers coated from such coating compositions have desirable high conductivity at low coverages. One particu-35 larly preferred method of preparing the polymer particles having ~.

the polyaniline salt semiconductor associated therewith is to loadthe particles with the semiconductor according to an adapta-tion of the method described by Chen in Research Disclosure, No. 15930, Vol. 159, July, 1977. It is preferred to adapt the process of Chen by first forming a polyaniline-loaded latex and then con-

5 verting this latex to a polyaniline salt-loaded latex by treatment with acid. The adapted process of Chen is particularly preferred when used with the polyaniline salt semiconductor because large quantities of the semiconductor can be associated with the polymer particles uslng this method.
The preferred adapted loading process is a five-step process. First, a solution is formed by dissolving a polyaniline in a water-miscible organic solvent. Second, a latex is formed by dispersing hydrophobic loadable polymer particles in an aqueous continuous phase. Third, the latex is blended with the solution 15 of the polyaniline. Fourth, the polymer par-ticles are loaded by removing the organic solvent. This s-tep forms a polyaniline-loaded latex. Finally, in the fifth step, the polyaniline-loaded latex is converted to a polyaniline salt-loaded latex by acidify-ing the latex with a suitable acid. The resulting polyaniline 20 salt-loaded latex forms an excellent coating composition having a semiconductor associated with the latex polymer particles. A
useful conductive element can be prepared by coatiny the describ~d latex coating composition on a suitable support/ removing the continuous phase of the latex and coalescing the latex so as to 25 form a conductive layer on the support.
The polyanilines which can be used to form the coating compositions and elements of the present invention are described in US Patent 3,963,498 to Trevoy. More particularly, the poly-aniline component is the D moiety which is described by Trevoy in 30 column 3, line 15, through column 6, line 8. Specific useful polyanilines can be found in Table 1 of the patent at column 6, line 63, through column 7, line 30. While all of the poly-anilines described by Trevoy can be used in the preferredcompositions and elements o~ the present ~nvention, the pre~erred imines are N-{~-[4 (~-methoxyanilino)anillno]-phenyl}-1,4-benzoqulnone imine (polyaniline (a)), N-{~-[~
(anilino)anilino]phenyl}-1,4-benzoquinone dilmine (poly-aniline (b)) and N-{p-[4 (~-methylanilino)anilino]}phenyl-1,4-benzoquinone imine (polyaniline(c)).
In order to ~orm the loaded latex which is useful as the pre~erred coating composition of the present invention, the polyaniline or semiconductor is dissolved in a water-miscible organic solvent. Use~ul solvents are those which:
(a) can be dissolved in distilled water at 20 C to the extent o~ at least 20 parts by volume of solvent in 80 parts by volume of water;
(b) have boiling points (at atmospheric pres-sure) above about -10 C.;
(c) do not detrimentally react chemlcally or physically with latex polymer or the semiconductor and (d) do not dissolve more than about 5 weight percent of the loaded polymer particles at 20 C.
Useful water-miscible organic solvents are water-miscible alcohols, ketones and amides, tetrahydro-~uran, N-methyl-2-pyrrolidone~ dimethylsulfoxide and mixtures thereof. Particular examples of these solvents include acetone, ethyl alcohol9 methyl alcohola :Isopropyl alcohol, dirnethylformamide, methyl ethyl ketone and the like. The polyanilines are generally soluble in acetone and this is the preferred solvent for the preferred pro-cess.
Use~ul latex polymers, in addltion to beingcapable of associating with the semiconductor, should meet several requirements. The latex polymers must be cat-ionically stabilized and should have a glass transition temperature less than about 65 C. The polymer partlcles should be capable o~ forming a fully coalesced layer under condltions which do not degrade the physical or chemical properties of the support.

.

The aqueous latices which are the pre~erred coatiny compositions consist essentially of water as a continuous phase and loaded polymer particles as a dispersed phase. The loadable polymer particles are those which meet the following test. At 25 C, the loadable polymer particles being tested must (a) be capable 5 of forming a latex with water at a polymex-particle concentration of from 0.2 to 50 percent by weight, preferably 1 to 20 percent by weight, based on total weight of the latex, and (b) when 100 mL of the latex is then mixed in an equal volume of the water-miscible organic solvent to be employed in forming the loaded polymeric 10 latex composi-tion, stirred and allowed to stand for 10 minutes, exhibit no observable coagulation of the polymer particles.
Further, the latex, after being loaded wi-th the polyaniline, must be able to be acidified without exhibiting observable coagulation, again for about 10 minutes. Useful loadable polymer particles are 15 disclosed by Chen in Re'search Disclosure, No. 15930, Vol. 159, July 1977. More particularly, useful loadable polymer particles are the cationically stabilized polymers of the polymers described in the 'Research Disclosure at page 63, column 2, through page 67, co lumn 1 .
T.J. Chen has now discovered that certain cationically stabilized polyurethane latex polymer particles meet his described loading test. He has unexpectedly found that these urethanes form loaded latices which are more stable than loaded latices which are made from other conventional latices. By "stable" it is meant 25 that the loaded urethanes can be stored for long periods, i.e., 30 days or longer, without observable coagulation. As a result of this property, hydrophobes which have been diEficult to load because of crystallization, etc., can now be loaded onto/into these urethanes. The discovery that loaded, cationically 30 stabilized polyurethanes are surprisingly stable is not our dis-covery, but is the discovery of T.~. Chen made prior to our dis-covery that cationically stabilized latices loaded with polyaniline ..~

g salt semiconductors form coatings with unexpected conductivity.
Polyurethane latlces which can be loaded according to the discovery of Chen are polyurethanes derived from a polyol component and an isocyanate component. The polyol unit can comprise:
(a) from 10 to 100 mole percent o~ one or a mixture of prepolymers having two or more than two hydroxy end groups and a molecular weight from 300 to 20,000, preferably from 500 to

6,000, the recurring units in said polyols being lower alkyl ethers or lower alkyl esters; and correspondingly (b) 90 to 0 mole percent of a low-molecular-weight diol with or without a functionality to impart a positive or a negative charge to the resulting polyurethane latex polymer.
The isocyana-te component can comprise one or a mixture of diisocyanates conforming to the structure OCNRNCO, wherein R
15 is alkylene, alkylene-containing hetero atoms such as oxygen, cycloaliphatic, e.g., cyclohexylene, alkylenebiscyclohexylene and isophorone-1,4-diyl, arylene, substituted arylene, alkylenebisar-ylene and arylenebisalkylene. More particularly, urethanes which can be loaded according to the discovery of Chen to form highly 20 stable latices can be represented by the structure:
t ~X
-t-Z-R2-Z-t~ 11 o wherein R is as described above; Rl is:

~ZR3~m{Z~C)mR4}nZ-or ~.3~3 -Z~R5-z-c-R6~c-zt--R5 -Z
Il 11 1 o o wherein each Z is independently -0- or -NH-; R , R3 and R5 are independently selected from alkylene of about 2-10 carbon atoms, cycloalkylenebis(oxyalkylene) such as 1,4-cyclohexylenebis(oxy-ethylene), arylenebisalkylene such as phenylenebismethylene, or the residue of a poly(alkylene oxide) group such as ~alkylene-Otpr 5 the alkylene having about 2-4 carbon atoms and p being about 2-500;
R4 is an alkylene group of about 2-10 carbon atoms; R6 is alkylene of about 2-10 carbon atoms or arylene such as phenylene, naphth-ylene, bisphenylene, oxydiphenylene and the like; 1 and n are in-dependently 2-500; m is 0 or 1; y is 0 to 90 mole percent of the 10 diol component of the polyurethane; and z is the -total isocyanate component of the polyurethane; the ratio of (x ~ y) to z being about 0.4 to 1Ø
A wide Variety of polyols and diisocyanates can be used to form stable loadable urethanes according to Chen~ Ap-15 propriate polyols include: ~1) diols such as alkylenediols of2-10 carbon atoms, arylenediols such as hydroquinone, and poly-ether diols CHO~CH2CH20tnH~; (2~ -triols such as glycerol, 2-ethyl-2-hydroxymethyl-1,3-propanediol, l,l,l-trimethylolpropane and 1,2,6-hexanetriol; (3) tetraols such as pentaerylthritol; higher . 20 polyols such as sorbitol; and poly(oxyalkylene) derivatives of the various polyhydric alcohols mentioned. Other desirable polyols include linear polyesters of ~W ~ 500 with terminal hydroxyl groups, low acid numbers and water content; block co-polymers of ethylene and propylene oxides with a diamine such as 25 ethylenediamine; and caprolactam polymers having end hydroxyl groups. Typical diisocyanates include 2,4- and 2,6-toluene di-isocyanate, diphenylmethane 4, 4'-diisocyanate, polymethylene polyphenyl isocyanates, bitolylene diisocyanate, dianisidine diisocyanate, 1,5-naph-thalene diisocyanate, 1,6-hexamethylene 30 diisocyanate, bis(isocyanatocyclohexylmethane diisocya-~ 7~
!~ .

~:~.3~

nate, isophorone diisocyanate, 2,2,4-(2,4,4)-trimethylhexa-methylene diisocyanate, and xylylene diisocyanate.
Polyurethanes which are useful herein are those de-scribed above which are cationically stabilized. These polyure-thanes comprise a polyol uni-t which imparts a positive charye to 5 the polyurethane. Useful polyurethanes which are cationically stabilized include those described in US Patent 3,873,484.
Latices of this type are commercially available from the Witco Chemical Corp under the designation Witcobond W-210TM.
Other particularly useful cationically stabilized latex 10 polymer dispersions which have been loaded ~ith polyaniline salt semiconductor are listed below. The number in parentheses after a polymer, here and throughout this specification, indicates the weight percentage o~ the respective monomers in the polymer.

(1) poly(n butylmethacrylate-co-vinylbenzyl chloride) (90/10) quaternized with trimethylamine (2) poly vinyl acetate-co-tetrahydrofurfuryl metha-crylate-co-methyl methacrylate-co-~N,N,N-trimethyl-N-vinylbenzylammonium chloride) (70/20/5/5) quaternized with trimethylamine (3) poly (vinyl acetate-co-methyl methacrylate) (90/10) (4) poly~tetrahydrofurfuryl methacrylate-co-N,~,N-trimethyl-N-vinylbenzylammonium chloride~ (90/10) quaternized with trimethylamine (5) poly{methyl acrylate-co-tetrahydrofurfuryl methacrylate-co-~2-(methacryloyloxy)ethyl trimethylammonium methosulfate~} (35/60/5) (6) poly ~-butyl methacrylate-co-butyl acrylate-co-(N,N,N-trimethyl-N-vinylbenzylammonium chloride~
(70/20/10) quaternized with trimethylamine

(7) poly(vlnyl acetate) After the solution of the polyaniline and the disper-sion of the loadable polymer particles are ~ormed, the -two are blended. Generally, it is preferred to blend ... .
c.< ~

~L~ 3~

the water-miscible organic solvent solution into the dispersion of the loadable polymer particles Blending is undertaken so that khe polyaniline re~ains in solution and the loadable polymer particles remain dispersed.
While blending of water and the loadable polymer particles with the water-miscible organic solvent solut~on of the polyaniline can result in significant loading o~
the polyaniline into the polymer particles 9 some of the polyaniline could still remain in the continuous phase dissolved in the water-miscible organic solvent. It is pre~erred further to load the polyaniline into the polymer particles by removing at least a major portlon Or the water-miscible organic solvent. While any o~ the methods of remcving the water-miscible organic solvent disclosed in the above-cited Research Disclosure of Chen Gan be used, it is preferred to remove rapidly the water miscible organic solvent by evaporakion under reduced pressure.
The result of these steps is that the loadable polymer particles have associated therewith (i.e., loaded) the polyaniline component Or the semiconductor.
It is preferred that the loading o~ the poly-aniline take place at a substantlally neutral pH. The polyaniline-loaded latex may only be stable at a pH of 7.0 for about 1-3 wks. However~ after acidification to ~orm the polyaniline salt-loaded latex, th~ pH is typically about 2.7. At this pH, the coatlng composition ls stable ~or long periods, i.e., greater than 30 days.
It is preferred that the loading of the poly-aniline and the subsequent acidification o~ the loaded latex take place in the presence of a surfactant. As is known in the art, the surfactant aids in keeping the hydrophob~c latex polymer particles in suspension. The surfactant is typically present at a concentratlon of about 2 percent by weight of the coating composition, although this concentration can be varied depending on the particular surfactant, latex, solvent and polyaniline.
Prererred surfactants are those having an HLB (hydrophile-lipophile balance) between about 13 and 17. Surfactants meeting this criteria include ethoxylated alkyl phenols ., .

~1.3~3 such as Igepal Co-730TM, Triton X-102 , Triton X-165TM and Igepal c0-630T ; and block copolymers o~ poly(ethylene oxi~e) and poly (propylene oxide) such as Pluronic L-64 and Pluronic L-44T .
The weight ratio of the polymer particles to polyani-line in the coating composition and therefore the coatings them-5 selves can vary over a wide range. It has been found that ~hisratio has little effect on the relationship between resistance of the coa~ing and the coverage of the semiconductor. The amount of binder can therefore be chosen to optimize the physical properties of the layer and the properties of the coating composition to lO facilitate coating. A useful range of the weight ratio of polymer to polyaniline is between about 1:1 and 20:1. Particularly de-sirable layers and coating compositions are formed when this ratio is between 4:1 and lQ:l.
The next step in the preferred process is to convert 15 the polyaniline-loaded polymer particles to polyaniline salt-loaded particles by acidifying the loaded latex dispersion which resulted from the previous step. Acidifying of the latex can be accomplished by simply mixing a solution containing the appro-priate acid with the latex dispersion. The amount and particular 20 acid should be chosen so that (a) substantially all of the poly-aniline is converted to polyaniline salt and (b) the resulting latex is stable for a time sufficient to form coatings. Where the acid chosen has the effect of destabilizing the latex, the coating composition containing the polyaniline salt-loaded latex 25 must be coated immediately. In preEerred embodiments, however, the latex should be storage-stable. Therefore, the acid should be selected so that, when it is mixed with the polyaniline-loaded latex, the resulting polyaniline salt-loaded latex is stable for at least lO minutes. The selection of a suitable acid to form 30 stable latices depends upon the presence of surfactants, the par-ticular loadable polymer particles chosen, the particular poly-aniline chosen, the pH of the initial polyaniline-loaded latex and other factors~ Useful acids include halogen acids, e.g., hydrogen chloride, hydrogen 3q~ 3 bromide, hydrogen fluoride, hydrogen iodide, rluoroboric acid and the like; sulfur acids such as sulf'urous acid, sulfuric acid, thiosulfuric acid, thiocyan~c acid and ~he like; acids of phosphorous such as phosphorous acld, phosphoric acid and the like; nltrogen acids such as nitrous acid, nitric acid and the like. Organic acids including mono-, di- and polyrunctional organic acids are also useful. Use~ul organic acids include aliphatic acids, both saturated and unsaturated, having from 1 to about 8 carbon atoms, for example, formic, acetic, pro-pionic, maleic and the like; aromatic acids such as phthalic, terephthalic~ benzoic and the like; and organic compounds containing acidic hydrogen atoms such as bar-bituric acid and 2-barbituric acid. Preferred acids ~or forming stable latex dispersions include phosphoric acid, nitric acid, and methanesul~onic acid Phosphoric acid forms stable latex dispersions and, in addition, forms coatings having exceptional con-ductivity, even in comparison with similar coatings of the invention using other acids. Phosphoric acid is therefore particularly preferred.
As mentioned above, sufficient acid is added to the latex to convert substantially 211 0~ the polyaniline to polyaniline salt. It can be desirable in some cir-cumstances to add excess acid to the polyaniline~loadedlatex. By "excess" we mean more than a stoichiometric amount. Excess acid assures that the latex rorms con-ductive coatings even if some of the acid is lost from the coating, such as by leaching. The amount Or acld added to the polyaniline-loaded latex can therefore vary over a wide range. Typically, useful amounts of acid fall within the range of 1.0 to 10.0 moles acid/mole imine. Where this ratio is greater than about 4:1, an overcoat layer may not properly adhere to the conducting layer. Where this ratio i~ less than about l.O, the layer may not have sufficient conductivity. Because the acid component of the polyaniline salt semiconductor can vary over this wide range, it is more accurate to describe the coverage in a layer of the semiconductor in terms of the coverage Or the polyaniline.
Preparation Or the pre~erred coating composition cornprising hydrophobic latex polymer particles loaded with polyaniline salt semlconductor has been described in detailO Loading in the described manner is the prererred method for associating the semiconductor with the latex.
It will be understood, however, that other methods can be used. For example, the semiconductor and the latex poly-mer can be chosen so that the semiconductor is soluble ina monomer which is used to form the latex polymer. So long as the polyaniline salt semiconductor is capable of being associated with the latex, the coating composition will produce layers having unexpectedly high conductivity in comparison with layers made from conventional coating compositions.
The weight percent solids in the latex coating compositions of the present invention can vary widely. As is well-known in the art, the percent solids, along wikh the method of coating~ has a substantial influence on the coverage of the layer that results from the coalescence of the coating composition. By "solids7' in this context we mean the suspended hydrophobic polymer particles including the semiconductor associated therewith. A useful range ~or the weight percent solids in the coating composition is between about 0.2 percent and about 15 percent.
~ oating compositions having latex polymer par-ticles having associated therewith the semiconductor can be coated on a wide variety Or supports to ~orm use~ul conducting elements. The support can be a number of materials which can take a number of forms. For example~
the coating compositions described herein can be coated on polymeric materials such as poly~ethylene terephthalate), cellulose acetate~ polystyrene, poly(methyl methacrylate) and the like. The compositions can also be coated on other supports such as glass, paper including resin-coated paper, and metals. Fibers 3 including synthetic fibers 9 use~ul for weaving into cloth9 can be used as the support.
Planar supports such as polymeric ~ilms useful in pho-~ .. . . .. . . . .

~3 ~

tography are particularly use~ul. In addition, the com-posi~ions of the present invention can be c~ated onto virtually any article where it is desired to have a con ductive coating. F~r example, the c~mpositions can be coated on small plastic parts to prevent the unwanted buildup of static electricity or coated on small polymer~c spheres or other shapes such as those used for toners in electrography and the like.
The compositions o~ the present invention can be coated onto the support using any suitable method. For example, the compositions can be coated by spray coating, fluidized bed coating, dip coating, doctor blade coating or extrusion hopper coating, to mention but a few.
A ma~or advantage of the conductive layers of the present invention is that they exhibit surprisingly high conductivity at low coverage of the semiconductor.
By low coverages we mean coverages of about 10 mg/m2 or less. Increasing the coverage beyond about 40 mg/m produces little increase in conductivity. The exact co~erage will depend on the particular semiconductor and latex chosen and, of course, the desired conductivity. In instances where optical density Or the conductive layer is not a problem, for example, where the layer is coated on an opaque support, high coverages can also be useful.
The coating compositions of the present inven-tion form useful conductive coatings by coalescing the latex having associated therewith the semiconductor after the composition has been coated. Typically, coalescence occurs by simply allowlng the continuous aqueous phase to evaporate. In some instances, depending upon the exact nature of the polymer particles, it may be necessary to heat the coated composition for a short period to coalesce the latex. This is well-known in the art. In some cases, improved physical properties result when the coalesced layer is cured by heating the layer, such as to about 120 C, for a short perlod~ such as for about 30 sec.
In some embodiments~ it may be desirable to coat the layer Or the compositions of the present in~ention with a protecti~e layer. The protective layer can be , . .. ,, .. . . , . . _ . ... . . . . . ~ , .. _ . . _ . . . _ . . _ .. _ . ...

~d~

present for a variety o~ reasons. For example~ the pro-tective layer can be an abrasion-resistant layer or a layer which provides other desirable physical properties.
In many embodiments, for example, it can be desirable to 5 protect the conductive layers of the present invention from conditions which could cause the leaching Or the acid component of the preferred polyaniline salt semiconductor.
Where the conductive layer of the present invention is part of an element having a basic layer, lt can be desira~
ble to provide a barrier in the form of a protective layer to prevent the contact of the conductive layer by base.
The protective layer is typically a film-forming polymer which can be applied using coating techniques such as those described above for the conductlve layer itself.
Suitable film-forming resins include cellulose acetate, cellulose acetate butyrate, poly(methyl methacrylate)~
polyesters, polycarbonates and the like. Currently pre-ferred protective layers include layers of poly(n-butyl acrylate-co-styrene)~ poly(_-butyl acrylate-co-methyl methacrylate), poly(_-butyl methacrylate-co-styrene), poly(methyl methacrylate) and poly(l,4-butylene-1,1,3-trimethyl-3-phenylindan-4',5-dicarboxylate).
The coating compositions of the present lnven-tion are particularly useful in forming antistatlc layers for photographic elements or conductive layers ln elec-trographic and electrophotographic elements. The com-positions of the present invention can provide high con-ductivity in layers having low coverages and there~ore low optical densities. Thus, the compositions of the present invention are particularly useful in forming antistatic layers for transparent photographic elements such as pro~ection transparencies, motion-picture film, microfilm and the like. Elements of this type comprise a support having coated thereon at least one radiation-sensitive layer. While the conductive layers described hereln can be ln any position in the photographic element~ it is preferred that the conductive layer be coated on the photographic support on the side Or the support opposite the slde having the coating of the radiation-sensitive ~3 -~8-- material. The coating compositions of the present inven-tion are advantageously coated directly on the support which can have a thin subbing layer as is known ln the art, and are then overcoated wikh the described protective layer. Alternatively, the conductive layers of the pres-ent invention can be on the same side Or the support as the radiation-sensitive materials and the protecti~e layers can be included as interlayers or overcoats, if desired.
The radiation-sensitive layers Or the photo-graphic or electrophotographic elements Or the present invention can take a wide variety of forms. The layers can comprise photographic silver salt emulsions, such as silver hal~de emulsions; diazo-type compositions; vesicu-lar image-forming compositions; photopolymerizable com-positions; electrophotographic compositions comprislng radiation-sensitive semiconductors; and the like. Pho-tographic silver halide emulsions are particularly pre-ferred and are described for example, ln Product Licens-ing Index, Publication 9232, Vol. 92, December, 1971,pages 107-110.
Another particularly useful element is an elec-trographic element. The conductive layers Or the presen~
invention, because of the uniformity of their conductlvlty and the humidity independence of their conductivity~ are excellent conductive layers for such an element. This embodiment of the present invention comprises a support having coated thereon the conductive layer as described herein and, as the outermost layer, a dielectric layer.
In this embodiment, the conductive layer can have some density so that high coverages of polyaniline~ such as about 35 mg/m2 can be used so that the resulting conduc-tive layer can have very high conductivity. Higher or lower coverages can also be used. The dielectr~c layer can be formed from any dielectric film-forming material such as any of the polymers listed above as useful as the protective layer. The currently preferred dielectric layer for this embodiment is poly(ethylene-co-4,4~-iso-propylidene bisphenoxyethyl terephthalate) which is described in ~S Patent 3,703,372. Optionally, and ln preIerred embodiments, the dielectric layer further comprises a ma~ting agent. Numerous ma~ting agents can be used such as polytmethyl methacrylate) beads described in ~S Patents 2,701,245 and 3,810,759. The currently pre-rerred matting agent is beads o~ polyethylene, along with some fluorocarbon such as PolyfluoTM #190 beads available from Micro Powders, Inc, of Yonkers, NY. This type of matting agent is preferred because it does not swell in the solvents used, thereby preventing bead agglomeration which degrades image quality. The use of electrographic elements Or the type described is well-known and i~
described, for example~ by Dessauer and Clark, Xerog-raphy and Related Processes, Focal Press, 1965, Chapter XVI, pp 439-450.
The resistance of the surface Or the coatings Or the present invention can be measured using well-known techniques. The resistivity is the electrical resistance of a square of a thin film Or material measured in the plane of the material between opposite sides. This ls described more fully in R. E. Atchison, _st. J. Appl.
Sci. 10 (1954).
The coverage o~ the imine component of the preferred conductive layer Or the present invention can be readily calculated using known methods.
The following examples are presented to illus-trate the practice of the invention and are not intended to limit the invention in any way.
Example 1:
(A) Preparation Or a polyaniline salt-loaded polymer latex A 28.4-g portion of a 35.2% by weight solid dispersion of Witco Bond W-210TM was diluted to a total weight of 400 g with water. To this was added a solution of 2.0 g Or N-{~-[4-(~-methoxyanilino)anilino~phenyl}-1,4-benzoquinone imine in 100 mL of acetone. The acetone was then removed by rotary evaporationg forming a polyaniline-loaded polymer d:lspersion of the Witco Bond W-210TM latex.
To 393 g Or the polyaniline-loaded latex were added 500 g ~20-Or water, 14 ML of 10% phosphoric acid, and then addi-tional water to total weight of 1,180 g. The resulting dispersion i~ a polyaniline salt-loaded latex.
(B) Preparation o~ a conducti~e coating The polyaniline sal~ dispersion described above was coated onto a subbed polyester support at a wet coverage of 10.8 mL/m2. The water sf the latex disperslon was removed by evaporation with a moderate amount of heat to give a coalesced film having an electrical resistivity of 2 x 106 ohm/sq and a dry coverage of the imine com-ponent of the layer o~ 17 mg/m2 of support. The inte-grated optical density o~ support between 400 an~ 700 nm was 0.015 Example 2:
A 100-g portion of the polyaniline salt-loaded latex prepared in Example 1 was diluted with water to a total weight of 333 g and coated at a rate of 8.6 mL/m2 onto a subbed polyester support. The water was removed by evaporation to give a coalesced ~ilm having a sur~ace electrical resistivity of 5 x 107 ohm/sq and a dry cov erage of the polyaniline component of 4.3 mg/m2 of sup-port.
Example 3:
A 107-g portion o~ the polyaniline-loaded latex dispersion prepared as in Example 1 was diluted with water to a total weight of 400 g. To this disperslon was added 3.65 mL of a 10% solution of methanesulfonlc acid. The resulting polyaniline salt-loaded latex was coated onto a subbed polyester support and the water removed by evapo-ration. The resulting coalesced film had a surface elec-trical resist~vity o~ 1.1 x 107 ohm/sq and a dry coverage of polyaniline component o~ 17 mg/m2 of support.
Example 4:
A polyaniline-loaded latex was formed as in Example 1, except that the imine chosen was N-{~-[~-(anilino~anilino]phenyl~-1,4-benzoquinone diimine. An 80-g portion Or thls polyaniline-loaded polymer dispersion was diluted to a weight of 340 g with water, and 2.70 mL
o~ a 10% solution of phosphoric acid was added. The resulting polyaniline salt-loaded latex dispersio~ was coated onto a subbed polyester support. The water Or the latex was removed by evaporation to give a coalesced film having a surface electrical resistivity of 9.3 x 106 ohm/sq and a dry coverage Or the polyaniline component o~
17 mg/ft of support.
Example 5:
(A) Preparation o~ a polyaniline salt-loaded latex To 30.39 g of a 16.45% solids latex o~ poly(n-butyl methacrylate-co-vinylbenzyl chloride) (90/10) qua-ternized with trimethylamine was added 0.10 g o~ Igepal Co-730~M Surfactant, as a dlspersing aid, and water to give a total weight of 200 g. To thls latex was added a solution of 1.0 g of the polyaniline of Example ~ in 55 mL
of acetone. The acetone was removed by rotary evaporatlon to produce a polyaniline-loaded latex. To 1.7 g of the imine-loaded latex dispersion were added 200 g Or water, 3.8 mL of a 10% solution Or phosphoric acid, and addi-tional water for a total weight of 400 g. The result wasa polyaniline salt-loaded latex.
(B) 5Oating of the polyaniline salt-loaded latex The latex ~rom step (A) was coated onto a subbed polyester support at a coverage of 10.8 mL/m2. The water was removed by evaporation to give a coalesced film havlng a surface electrical resistivity of 5 x 106 o~n/sq and a dry coverage of the polyaniline component o~ 17 mg/m2 of support. The inte~rated optical density in the 400-700 nm region was 0.015.
Example 6:
This is a comparative example.
A polyaniline salt-loaded latex was prepared according to the procedures set forth in Example 1. The latex used was a 5~ by weight latex Or poly(n-butyl acry~
late-co-2-acrylamido-2-methylpropanesul~onic acid) (90/10~, an anionically stabilized latex. The polyanillne was N-{~-~4-(~-methoxyanillno)anilino]phenyl}-1,4-benzo-quinone imine which was ~ntroduced into the latex using a 0.5% by weight solution o~ the imine in acetone~ To 4~' g of this polyaniline-loaded latex were added 7.3 mL of a 2%
phosphoric acid solution in water to form the polyaniline salt-loaded latex. This latex was coated onto a subbed polyester support and the water was removed by evaporation 5 to give a coalesced rilm. The film had an electrical resistivity of 2.0 x lO9 ohm/sq and a covera~e of the polyaniline component of 16 mg/m2.
Example 7:
This is a comparative example.
A conductive coating was prepared using the polyaniline salt of Example l in a gelatin binder in the following manner: An amount of 400 mL of a 1% by weight gelatin solution was warmed to 40 C and 4.0 mL of a solution containing 1% by weight Olin lOGTM surfactant and 0.76 g of 85g phosphoric acid were added. Then 25 mL of a solution containing o.8 g of the polyaniline of Example l in acetone were added to the gelatin solution with strong agitation. The acetone was removed by rotary evaporation leaving a finely divided dispersion of the polyaniline salt in the gelatin solution. The polyaniline salt was not associated with the gelatin. This dispersion was coated on a suitable polyester support so as to produce a coverage Or the polyanillne of about 28.6 mg~m2 Or sup-port. Arter drying, the layer had a resist~vity of 5.3 x 108 ohm/sq. This example illustrates that conventional layers of polyaniline salt semiconductors, even when the semiconductor is coated at almost twice the coverage, do not exhlbit the high conductivity of the layers of the present invention. Compare Example l's coverage of 17 mg/m and resistivity o~ 2 x 106 ohm/sq with comparative Example 7's coverage of 28.6 mg/m and resistivlty of 5.3 x 108 ohm/sq.
Example 8:
This is a comparative example.
A conductive coating was prepared using the polyaniline salt of Example l and the latex binder of Example l, except that the polyaniline salt was not asso-ciated with the latex before coating and coalescing. The conductive layer was prepared in the follo~ing manner: To 180 mL o~ water containing 6.2 mL of 10% phosphoric acid and 0.1 g of Igepal C0-730TM surfactant were added 25 mL
of an acetone solution containing 1.05 g o~ the polyani-line of Example l and 0.1 g of Igepal C0-630TM. The addition was made with strong agitation. The acetone was removed from the resulting solution, resulting in a finely divided dispersion of the polyaniline salt semiconductor in water. To this dispersion were added 14.2 g of a 3~%
by weight solids dispersion of Witco Bond W-210TM latex.
Under those conditions, no noticeable amount of semicon-ductor became associated with the latex; rather~ a codis-persion of semiconductor and latex was formed. This codispersion was coated on subbed polyester support and dried to form a coalesced layer having polyaniline cov-erage of 10.8 mg/m of support. This layer had a resis-tiv~ty of 3.8 x 107. A layer coated from the loaded latex described in Example l was coated at the same coverage and had a resistivity of 3.5 x lO~. When this comparison was repeated at a coverage of polyaniline of 5.4 mg/m , resistance of the coating made from codispersion was 4.3 x 108 ohm/sq, more than an order Or magnitude increase, while the coating made from the loaded latex increased by less than a factor of two to 6.3 x 106 ohm/sq.
Examples 9-12:
These are comparative examples.
In a manner similar to Example 8, coatings were made rrom codispersions and from coating compositions of the present invention using various polyanilines and acids.
Codispersion preparations (identlfied a and c):
A solution of 1.0 g of the polyanlline and 0.1 g of Igepal C0-630TM surfactant ln 55 mL of acetone were added to 200 mL of a strongly agitated~ aqueous solution containing 0.2 g Igepal 730TM surfactant and sufficient acid to produce a ratio of 2.5 moles acid/mole polyani-line. The acetone was removed ~rom the resulting solution to produce a disperslon of polyaniline salt in water. To this dispersion were added 5.0 g of latex polymer (Wit-cobond W-210TM) solids to form a codispersion o~ poly-aniline salt and latex polymer.
Loa~ed latex preparation (identified b and d):
Latices loaded with polyaniline salt were pre-pared in a manner similar to Example 1.
Both the loaded latex of the invention and the codispersion were coated at coverages of 10.8 and 5.4 mg polyaniline/m2. The results are shown in table 1.
Examples 13-19:
Example 1 was repeated, substituting various cationically stabilized latex polymers ~or Witcobond W-210TM. In each case, the weight ratio of latex poly-mer/polyaniline was 5:1. The results are shown in Table 1. The numbers for the polymers are given above in the discussion of useful loadable polymers.
The following table reproduces pertinent data from the above examples. Where appropriate, the desig-nation for the polyaniline and for the binder corresponds to the designation given these components above.

--2~i--O
~r~
h h ~ h h h h h h ~

O O O O O O O O O O
b Q) a~
o h S~ h h h ~ h h ~ h h h ~ E
O O O O O O O O O O O O
C) C~ C) C) C~ C) U t~
c~ D o~ D r~ r~l ~D r~l t--~ ~D c~ t~
ooo o oo oooooo o o o oooooooooooo ~1 ~ r~ lr~ r-l r~ r~ r~ r-l r~ r-l r~ r~ r~ r~l r1 r~ r~l r~l ~ ~I r~ r~ r~ r~t r~l X X ~ X X ~ X X X X X ~ X X X X X X X X X ~C
O ~a:) Lr~ ~ ~ t-- CO O t~l ~D ~ O ~ C--u~ O .. . . ~
~ ~ cs~~ Lr~ t~ ~J ~D ~ r~l ~ J 3 t~ r~~ 3 a~ r~l L

a) t~ ~ J a~ t J 0~ a:) a ~ 0:) a:) 3 3 Ot~ r 3 3 h a~ ~ C--J ~ O O If ~ O .0 U' Il~ O O 11~ ~n O O Ir~ O O Ir~ L~
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P C~
E~ u h rl X ~
OOO OO~OOOOO O O O OOOOOOOOOOOO
~: r~ r~l r-1r~ d a;l r~ r~l r-l r~l r~l r~l r~l r~l r~ r-l r~l r~ r~ r-t r~ r-1 r~ r~l r-l N N N t~J~ ~i r~l ~J N ~J N N N N t~ .1 N N N ~ U N ~J ~J tU N
m , I II r-l ~ ~) I I I I I I I I I I I I I I I I I I I I

h h ~S: h h h h h h h ~ h h h h h h h h o o ~ o a) o o o o o o o o a) o a) o ~ o ~ o o o o o o o o o c~ ~ ~ 0 ~I td ~ ~ P~ ~ ~ p, ~ ~4 td r~l ~d r~ ~d r~l t~
n tn S ~ S ~ tn tn tn tn tn tn tn S ~ S ~ S 3 S ~ h h h h tn tn u~ tn rn tn ~n tn o 0~ tn~ tn o 0 0 o 0 0 o~ tnJ~ tn~ rn~ tn~ o O O O O o O O
.~ ~ .C ~ .C tl ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ,C S

~: td td rd R ~ ~ ad s~ ~ rd ~ d ~ sd td .Q P ~ ~ U ~ c) c~
o r~l P ~ a t~ 5~ ~ ~ rd ~ v ~ ~ ~ v ~a ~d D v ~a E~ r-l tu ~ 3Ir~D ~t~ C~ t~ ~ tr~ a~ O O O O r~ r~ r~ r~ t.~J N ~J ~J
t~d r1 r-J t1 r~ r~l r~ r--I r~l r-t r~ r~l r~
~C
P:

. .. . . , . ,.. _ . _ .. . _ _ ,~ _ . . , _, , ~ 3.3~

V

~ ~o ~o ~o ~ ~o ~o ~o .,1 Q O O Q O O O
CJ r~ r-l r~l r-l r~ r-l r~l ~Q
~ X X X X X X X
~1 S 0 3 ~rl r~
U:) O .. . ..
a~ ~ ~1 3 t~l C
_~ ~
~1 h E~ .......
Q~ O O O O O O O
11~ ~> bO r~ r-l r~ r~ r~l r-l ~1 r-l O
Q ~>
E~
h a) l ~3 1~0 h h h h h h h ~ O O O O o O O
rl S ~ .C .C S S
C~ ~ ~ ~ Q~ ~ P. P~
¢ U~
OOOOOOO
5: S~.C CSS
P~
U~
~C
~i ~ , ~ ,~

r~l o a-r-1 r~ r~ r~l r~
~C

b~

Example 20:
An electr~graphic element was prepared by coat-ing a conductive layer on a subbed poly(ethylene tereph-thalate) fllm support and then overcoating the conductive layer with a dielectric layer. The conductive layer was coated using the coating composition described in Example 1, wherein the weight ratio of latex to polyaniline was 5:1, so as to produce a coverage of polyaniline salt of about 30 mg/m2. The dielectric layer was a 3.5~micron layer of poly(ethylene-co-4,4'-isopropylidene bisphenoxy-ethyl terephthalate) (50:50) containing 3.5 weight percent Poly~luoTM #190 matt beads. A spreading agent as described in US Patent 3,861,915 was used in coating the dielectric layer.
The described electrographic element was imaged on a Gould #5005 Plotter/Printer stylus recording device and toned with a liquid electroscopic developer. Image quality was excellent.
The invention has been described ln detail with particular rererence to preferred embodiments, but it will be understood that variations and modifications can be e~ected without departing from the spirit and scope of the invention.

. . , . _ . . .

Claims

We claim:

1. A coating composition comprising a latex having water as a continuous phase and, as a dispersed phase, cationically stabilized, hydrophobic polymer par-ticles having associated therewith a polyanillne acid addition salt semiconductor.

2. A coating composition according to Claim 1 wherein said hydrophobic polymer particles are loaded with said semiconductor.

3. A coating composition according to Claim 1 wherein the weight ratio of the hydrophobic polymer par-ticles to the imine of said polyaniline salt semiconductor is between 4:1 and 10.1.

4. A coating composition according to Claim 1 having a weight percent solids between 0.2 percent and 15 percent.

5. A coating composition according to Claim 1 wherein the polyaniline of said polyaniline salt semi-conductor is selected from the group consisting of:
N-{?-[4-(?-methoxyanilino)anilino]phenyl}-1,4-benzoquinone imine and N-{?-[?-(anilino)anilino]phenyl}-1,4-benzoqui-none diimine.

6. A coating composition of Claim 1 wherein said polyaniline salt is the phosphoric acid addition salt.

7. A coating composition according to Claim 1 wherein said hydrophobic polymer particles comprise cationically stabilized, substantially linear, polyure-thane urea.

8. A coating composition according to Claim 1 wherein said hydrophobic polymer particles are particles of poly(n-butyl methacrylate-co-vinylbenzyl chloride) (90/10) quaternized with trimethylamine.

9. A process for preparing a coating compo-sition comprising a latex having water as a continuous phase and, as a dispersed phase, cationically stabilized, hydrophobic polymer particles having associated therewith a polyaniline acid addition salt semiconductor, said process comprising the steps of:
(a) forming a solution by dissolving a polyaniline in a water-miscible organic solvent;
(b) forming a latex by dispersing cationically stabilized, hydrophobic loadable polymer particles in an aqueous continuous phase;
(c) blending said latex with said solu-tion;
(d) loading said polymer particles by removing said organic solvent thereby forming a polyaniline-loaded latex; and (e) forming a polyaniline salt-loaded latex by adding sufficient acid to said polyaniline-loaded latex to convert substantially all of said polyaniline-loaded latex to polyaniline salt-loaded latex.

10. A process according to Claim 9 wherein said organic solvent is removed in step (d) by evaporation under reduced pressure.

11. A process according to Claim 9 wherein said acid is added in step (e) at a ratio of 1:1 to 10:1 moles acid/mole polyaniline.

12. A process according to Claim 9 wherein said water-miscible organic solvent is selected from the group consisting of alcohols, ketones, amides, tetrahydrofuran, N-methyl-2-pyrrolidone and dimethylsulfoxide.

13. A process according to Claim 9 wherein said water-miscible organic solvent is acetone.

14. A process according to Claim 9 wherein said polyaniline in step (a) is selected from the group con-sisting of:
N-{p-[4-(p-methoxyanilino)anilino]phenyl}-1,4 benzoquinone imine and N-{p-[p-(anilino)anilino]phenyl}-1,4-benzoqui none diimine.

15. A process according to Claim 9 wherein said acid is phosphoric acid.

16. A process according to Claim 9 wherein said hydrophobic polymer particles comprise cationically stabilized, substantially linear, polyurethane urea.

17. A process according to Claim 9 wherein said hydrophobic polymer particles are particles of poly(N-butylmethacrylate-co-vinylbenzyl chloride) (90/10) qua-ternized with trimethylamine.

18. In an element comprising a support having thereon a conductive layer comprising a coalesced, cationically stabilized latex and a semiconductor, the improvement wherein said latex and said semiconductor are chosen so that said semiconductor is associated with said latex before coalescing and said semiconductor is a poly-aniline acid addition salt.

19. An element according to Claim 18 wherein said conductive layer is coated with a protective layer.

20. An element according to Claim 19 wherein said protective layer comprises a polymer selected from the group consisting of poly(n-butyl acrylate-co-styrene), poly(n-butyl acrylate-co-methyl methacrylate), poly(n-butyl methacrylate-co-styrene) and poly(methyl methac-rylate).

21. An element according to Claim 18 wherein the weight ratio of latex to polyaniline component is between 4:1 and 10:1.

22 An element according to Claim 18 wherein the polyaniline of said polyaniline salt is selected from the group consisting of:
N-{?-[4-(?-methoxyanilino)anilino]phenyl}-1,4-benzoquinone imine and N-{?-[?-(anilino)anilino]phenyl}1,4-benzoqui-none diimine.

23. An element according to Claim 18 wherein said polyaniline salt is the phosphoric acid addition salt.

24. An element according to Claim 18 wherein said coalesced latex comprises cationically stabilized, coalesced, substantially linear, polyurethane urea.

25. An element according to Claim 19 wherein said coalesced latex comprises coalesced particles of poly(N-butylmethacrylate-co-vinylbenzyl chloride) (90/10) quaternized with trimethylamine.

26. In a photographic element comprising a support having coated thereon (a) at least one radiation-sensitive layer and (b) a conductive layer comprising a coalesced, cationically stabilized latex binder and a semiconductor, the improvement wherein said latex and said semiconductor are such that said semiconductor is asso-ciated with said latex before coalescing and said semi-conductor is a polyaniline acid addition salt.

27. A photographic element according to Claim 26 wherein said radiation-sensitive layer comprises a pho-tographic silver salt emulsion.

28. An element according to Claim 26 wherein said conductive layer is coated with a protective layer.

29. An element according to Claim 26 wherein said protective layer comprises a polymer selected from the group consisting of poly(n-butyl acrylate-co-styrene), poly(n-butyl acrylate-co-methyl methacrylate), poly(n butyl methacrylate-co-styrene) and poly(methyl methac-rylate).

30. An element according to Claim 26 wherein the weight ratio of latex to polyaniline is between 4:1 and 10:1.

31. An element according to Claim 26 wherein the polyaniline of said polyaniline salt is selected from the group consisting of:
N-{?-[4-(?-methoxyanilino)anilino]phenyl}-1,4-benzoquinone imine and N-{?-[?-(anilino)anilino]phenyl}1,4-benzoqui-none diimine.

32. An element according to Claim 26 wherein said polyaniline salt is the phosphoric acid addition salt.

33. An element according to Claim 26 wherein said coalesced latex comprises cationically stabilized, coalesced, substantially linear, polyurethane urea.

34. An element according to Claim 26 wherein said coalesced latex comprises coalesced particles of poly(N-butylmethacrylate-co-vinylbenzy1 chloride) (90/10) quaternized with trimethylamine.

35. In an electrographic element comprising a support having coated thereon a conductive layer and an outermost dielectric layer, the improvement wherein said conductive layer comprises a coalesced, cationically stabilized latex binder and a polyaniline acid addition salt semiconductor, wherein said latex and said semicon-ductor are such that sald semiconductor is associated with said latex before coalescing.

36. An element according to Clalm 35 wherein said dielectric layer further comprises a matting agent.

37. An element according to Claim 35 wherein the polyaniline of said polyaniline salt is selected from the group consisting of:
N-{?-[4- [?-methoxyanilino)anilino]phenyl}-1,4-benzoquinone imine and N-{?,-[?-(anilino)anilino]phenyl}-1,4-benzoqui-none diimine.

38. An element according to Claim 35 wherein said polyaniline salt is a phosphoric acid addition salt.

39. An element according to Claim 35 wherein said latex binder comprises cationically stabilized, substantially linear polyurethane urea.

40. A process of preparing a conductive element comprising a support having thereon a conductive layer, said process comprising the steps of:
(a) forming a latex having water as a continuous phase and, as a dispersed phase, cationically stabilized, hydrophobic polymer particles having asso-ciated therewith a polyaniline acid addition salt semi-conductor;
(b) coating said latex on said support;
(c) removing said continuous phase; and (d) coalescing said latex so as to form said layer.

41. A process according to Claim 40 wherein said latex in step (a) is prepared by a process which comprises the steps of:
(i) forming a solution by dissolving a polyaniline in a water-miscible organic solvent;
(ii) forming a latex by dispersing said hydrophobic loadable polymer particles in an aqueous continuous phase;
(iii) blending said latex with said solu-tion;
(iv) loading said polymer particles by removing said organic solvent thereby forming a polyaniline-loaded latex; and (v) forming a polyaniline acid addition salt-loaded latex by adding sufficient acid to said polyaniline-loaded latex to convert substantially all of said polyaniline-loaded latex to polyaniline salt-loaded latex.