Conductive polymers

• US 5,807,506 A
• Filed: 04/01/1997
• Issued: 09/15/1998
• Est. Priority Date: 04/01/1997
• Status: Expired due to Term

• Current Assignee: Xerox Corporation (Xerox Holdings Corp.)
• Original Assignee: Xerox Corporation (Xerox Holdings Corp.)
• Inventors: Hawkins, Michael S., Mahabadi, Hadi K., Liebermann, George, Enright, Thomas E., Cunningham, Michael F., McNeil, Daniel M., Cogswell, Aron J.
• Primary Examiner(s): Lieberman, Paul
• Assistant Examiner(s): KOPEC, MARK T
• Application Number:
  US08/829,419
• Time in Patent Office: 532 Days
• Field of Search: 252/511, 252/512, 252/513, 252/514, 252/518.1, 252/519.33, 252/520.1, 252/520.2, 524/495, 524/496
• US Class Current: 252/511
• CPC Class Codes: C08F 292/00 Macromolecular compounds obtained by polymerising monomers on to inorganic materials
• CPC Class Codes: H01B 1/20 Conductive material dispersed in non-conductive organic material organic macromolecular compounds or compositions C08
• CPC Class Codes: H01B 1/22 the conductive material comprising metals or alloys
• CPC Class Codes: H01B 1/24 the conductive material comprising carbon-silicon compounds, carbon or silicon

Abstract

A process for the preparation of conductive polymers which comprises (a) mixing at least one monomer with at least one conductive component, solvent, at least one polymerization initiator, and an optional chain transfer component; (b) effecting solution polymerization by heating; (c) removing said solvent by azeotropic distillation in an aqueous phase to generate a mixture of polymer and conductive component; (d) drying and grinding the resulting mixture; thereafter dissolving the product resulting in at least one monomer, at least one initiator, and at least one crosslinking component, and an optional chain transfer agent to form an organic phase; (e) mixing said organic phase with a second aqueous phase comprised of water, stabilizer, and an alkali halide; (f) polymerizing the resulting suspension by heating; and (g) subsequently optionally washing and drying the polymeric product, and which product is comprised of polymer and conductive component dispersed therein.

Claims

1. A process for the preparation of a conductive polymer product which comprises (a) mixing at least one monomer with at least one electrically conductive component, solvent, at least one polymerization initiator, and an optional chain transfer component;

(b) effecting solution polymerization by heating;

(c) removing said solvent by azeotropic distillation in an aqueous phase to generate a mixture of polymer and electrically conductive component;

(d) drying and grinding the resulting mixture;

thereafter dissolving the intermediate product in a solution comprising solvent, at least one monomer, at least one initiator, and at least one crosslinking component, and an optional chain transfer agent to form an organic phase;

(e) mixing said organic phase with a second aqueous phase comprised of water, stabilizer, and an alkali halide to form a suspension;

(f) polymerizing the resulting suspension by heating; and

(g) subsequently optionally washing and drying the polymeric product, and which product is comprised of polymer and conductive component dispersed therein.

2. A process in accordance with claim 1 wherein said aqueous phase for the azeotropic distillation is comprised of water, or water and a stabilizer of polyvinyl alcohol.

3. A process in accordance with claim 1 wherein said alkali halide is potassium iodide.

4. A process in accordance with claim 1 wherein there is accomplished washing and drying of the polymeric product, and which product is comprised of polymethyl methacrylate polymer and a conductive component of carbon black.

5. A process in accordance with claim 4 wherein washing is accomplished with a mixture of water and an alcohol, which water is present in an amount of from about 75 to about 95 weight percent.

6. A process in accordance with claim 1 wherein said mixing of said organic phase and said second aqueous phase is accomplished for from about 5 to about 20 minutes, followed by further mixing for a period of from about 10 to about 90 minutes, and said solvent is the organic solvent toluene;

and wherein said further mixing is with an inline homogenizer, or with a continuous homogenizer.

7. A process in accordance with claim 1 wherein said heating of step (f) is from about 65°

to about 125°

C.

8. A process in accordance with claim 1 wherein the mixture contains from 2 monomers to about 20 monomers.

9. A process in accordance with claim 1 wherein the solution and the suspension polymerization are accomplished by heating;

wherein heating is accomplished at a temperature of from about 30°

C. to about 200°

C.

10. A process in accordance with claim 1 wherein the number average molecular weight of the solution polymerization product (b) is from about 1,000 to about 50,000, and the weight average molecular weight of the solution polymerization product is from about 5,000 to about 100,000;

and wherein the number average molecular weight of the suspension polymerization product (f) is between about 3,000 to about 500,000, and the weight average molecular weight of the suspension polymerization product is between about 5,000 to about 2,000,000.

11. A process in accordance with claim 1 wherein the mixing of step (e) is accomplished with a high shear mixer, and wherein the product of solution polymerization is separated from the organic solvent by azeotropic distillation.

12. A process in accordance with claim 1 wherein the conductive polymer product obtained possesses an average volume particle diameter of from about 0.05 micron to about 5 microns.

13. A process in accordance with claim 2 wherein the weight percentage of conductive component in the final product is from about 1 to about 50 and wherein the conductive component is evenly distributed throughout the polymer matrix of the final product.

14. A process in accordance with claim 1 wherein the conductivity of the final conductive polymer product is from about 10^-10 to about 0.10 (ohm-cm)^-1 as determined by measuring the electrical resistivity of a pressed pellet thereof and wherein the triboelectric charge of the polymer product is from about +40 to about -40 microcoulombs per gram.

15. A process in accordance with claim 1 wherein the monomer of step (a) is selected from the group consisting of methylstyrene, p-chlorostyrene, monocarboxylic acids and the derivatives thereof;

dicarboxylic acids with a double bond;

vinyl ketones;

vinyl naphthalene;

unsaturated mono-olefins;

vinylidene halides;

N-vinyl compounds;

fluorinated vinyl compounds and mixtures thereof.

16. A process in accordance with claim 1 wherein the monomer of step (a) is selected from the group consisting of acrylic acid, methyl acrylate, ethyl acrylate, butyl acrylate, dodecyl acrylate, octyl acrylate, phenyl acrylate, methacrylic acids, methyl methacrylate, ethyl methacrylate, butyl methacrylate, octyl methacrylate, acrylonitrile and acrylamide;

maleic acid, monobutyl maleate, dibutyl maleate;

vinyl chloride, vinyl acetate, vinyl benzoate;

vinylidene chloride;

pentafluoro styrene allylpentafluorobenzene, and N-vinyl pyrrole.

17. A process in accordance with claim 1 wherein the monomer is methyl methacrylate, the polymer is poly(methyl methacrylate), and the conductive component is carbon black.

18. A process in accordance with claim 1 wherein the conductive component is selected from the group consisting of conductive carbon blacks, metal oxides, metals, and mixtures thereof.

19. A process in accordance with claim 1 wherein the conductive component is selected from the group consisting of acetylene black, iron oxides, TiO and iron powder.

20. A process in accordance with claim 1 wherein the polymerization initiator is selected from the group consisting of azo compounds and peroxides.

21. A process in accordance with claim 1 wherein the polymerization initiator is benzoyl peroxide, lauroyl peroxide, 1-1-(t-butylperoxy)-3,3,5-trimethylcyclohexane, n-butyl-4,4-di-(t-butylperoxy) valerate, dicumyl peroxide, 2,2'"'"'-azodimethylvaleronitrile, 2,2'"'"'-azoiso butyronitrile, azobiscyclohexanenitrile, or 2-methylbutyronitrile, selected in an amount of from about 0.5 to about 3 weight percent, and wherein the stabilizing component is selected from a group consisting of nonionic and ionic water soluble polymeric stabilizers, selected in an amount of from about 0.1 to about 5 weight percent.

22. A process in accordance with claim 1 wherein the stabilizing component is selected from the group consisting of methyl cellulose, ethyl cellulose, hydroxypropyl cellulose, the sodium salt of carboxyl methyl cellulose, polyacrylate acids, polyvinyl alcohol, gelatins, starches, gums, alginates, zein and casein, selected in an amount of form about 0.1 to about 5 weight percent, and wherein the crosslinking component is selected from the group consisting of compounds with two or more polymerizable double bonds, selected in an amount of from about 0.01 to about 5 weight percent.

23. A process in accordance with claim 1 wherein the crosslinking component is divinylbenzene, divinyinaphthalene, ethylene glycol diacrylate, or divinylether, selected in an amount of from about 0.01 to about 5 weight percent, and wherein the chain transfer component is selected from the group consisting of mercaptans and halogenated hydrocarbons, selected in an amount of from about 0.1 to about 2 weight percent.

24. A process in accordance with claim 23 wherein the chain transfer component is carbon tetrachloride, butylmercaptan, or laurylmercaptan.

28. A process in accordance with claim 1 wherein there is accomplished washing and drying of the polymeric product comprised of polymethylmethacrylate polymer and with the conductive component carbon black, and wherein said carbon black is present in an amount of from 1 to about 50 weight percent, and wherein the polymer conductive component size diameter is from about 1 to about 5 microns in volume average diameter.

25. A process for the preparation of a conductive polymer product with an average volume particle size of from about 0.05 to about 5 microns which comprises (1) a solution polymerization of at least one monomer in the presence one or more initiators, an organic solvent, and in the presence of a electrically conductive component, and optional charge transfer agents;

(2) removing the solvent from the resulting slurry of (1) by azeotropic distillation wherein the organic solvent, polymer, conductive component slurry is added or admixed with a heated aqueous phase to enable the polymer slurry to be dispersed in droplets upon addition to the aqueous phase, and wherein the solvent evaporates thereby resulting in solid beads of polymer and conductive component;

(3) drying the solid beads of polymer and conductive component particles, and grinding;

(4) dissolving the ground prepolymer and conductive component of (3) in an organic phase comprised of at least one monomer containing one or more initiators, and a crosslinking agent, and mixing;

(5) premixing the organic phase with an aqueous phase of step (4) comprised of polyvinyl alcohol and potassium iodide, followed by circulating the mixture through an inline or continuous homogenizer;

(6) transferring the suspension of (5) into a second reaction vessel or reactor, and heating to accomplish polymerization;

(7) washing the slurry obtained, after cooling with a mixture of water and an aliphatic alcohol; and

(8) drying the wetcake to enable the product of a polymer containing from about 1 to about 50 weight percent of a conductive component dispersed therein.

26. A process in accordance with claim 25 wherein said average volume particle size is from about 1 to about 5 microns, said one is from 1 to about 3, and said conductive component is carbon black.

27. A process for the preparation of a conductive polymer product which comprises (a) mixing monomer with electrically conductive component, solvent, polymerization initiator, and an optional chain transfer component;

(b) effecting solution polymerization by heating;

(c) removing said solvent by azeotropic distillation in an aqueous phase to generate a mixture of polymer and electrically conductive component;

(d) drying and grinding the resulting mixture;

thereafter dissolving the intermediate product in a solution comprising solvent monomer, initiator, and crosslinking component, and an optional chain transfer agent to form an organic phase;

(e) mixing said organic phase with a second aqueous phase comprised of water, stabilizer, and an alkali halide to form a suspension;

(f) polymerizing the resulting suspension by heating; and

(g) subsequently washing and drying the polymeric product, and which product is comprised of polymer and conductive component.