Claims
- 1. A dry process for the preparation of conductive carrier particles consisting essentially of mixing carrier core with a first polymer pair and a second polymer pair, heating the mixture, and cooling the mixture; and wherein the first and second polymer pair each contain an insulating polymer and a conductive polymer and wherein the carrier conductivity thereof is from about 10.sup.-6 to about 10.sup.-14 (ohm-cm).sup.-1, and wherein said first polymer pair and said second polymer pair are triboelectrically dissimilar.
- 2. A dry process in accordance with claim 1 wherein the first polymer pair is comprised of an insulating polymer and a conductive polymer, and the second polymer pair is comprised of an insulating polymer and a conductive polymer; and wherein the conductive polymer contains dispersed therein a conductive component.
- 3. A process in accordance with claim 2 wherein the conductive component is carbon black present in an amount of from about 10 to about 50 weight percent.
- 4. A process in accordance with claim 2 wherein the first polymer pair is comprised of an insulating polymethylmethacrylate and a conductive polymethylmethacrylate, and the second polymer pair is comprised of an insulating polyvinylidene fluoride and a conductive polyvinylidene fluoride.
- 5. A process in accordance with claim 2 wherein the first polymer pair is comprised of an insulating polymethylmethacrylate and a conductive polymethylmethacrylate, and the second polymer pair is comprised of an insulating polytrifluoroethylmethacrylate and a conductive polytrifluoroethylmethacrylate.
- 6. A process in accordance with claim 4 wherein the conductive polymethylmethacrylate and the conductive polyvinylidene fluoride contain dispersed therein carbon black in an amount of from about 10 to about 40 weight percent.
- 7. A process in accordance with claim 5 wherein the conductive polymethylmethacrylate and the conductive polytrifluoroethylmethacrylate contain dispersed therein carbon black in an amount of from about 10 to about 40 weight percent.
- 8. A process in accordance with claim 1 wherein the polymer is rendered conductive with carbon black present in an amount of from about 10 to about 40 weight percent.
- 9. A process in accordance with claim 1 wherein the polymer is rendered conductive with carbon black present in an amount of from about 20 to about 40 weight percent.
- 10. A process in accordance with claim 1 wherein said core is steel, or a ferrite.
- 11. A process in accordance with claim 2 wherein said core is steel, or a ferrite.
- 12. A process in accordance with claim 1 wherein the first and second polymer pair each contain an insulating polymer with a conductivity of about 10.sup.-15 (ohm-cm).sup.-1 and a conductive polymer with a conductivity of about 10.sup.-2 (ohm-cm).sup.-1.
- 13. A process in accordance with claim 1 wherein the first polymer pair contains an insulating polymer with a conductivity of about 10.sup.-15 (ohm-cm).sup.-1, and the second polymer pair contains a conductive polymer with a conductivity of about 10.sup.-2 (ohm-cm).sup.-1.
- 14. A process in accordance with claim 1 wherein the first polymer pair is present in an amount of from about 1 to about 99 weight percent, and the second polymer pair is present in an amount of from about 1 to about 99 weight percent.
- 15. A process in accordance with claim 1 wherein the first polymer pair is present in an amount of from about 40 to about 60 weight percent, and the second polymer pair is present in an amount of from about 60 to about 40 weight percent.
- 16. A process in accordance with claim 1 wherein heating is accomplished at a temperature of from about 300 to about 550.degree. F.
- 17. A process in accordance with claim 1 wherein cooling is accomplished by termination of heating.
- 18. A process in accordance with claim 2 wherein cooling is accomplished to from about 25.degree. F. to about 100.degree. F. by termination of heating.
- 19. A process in accordance with claim 2 wherein the triboelectric charging value of the resulting carrier particles is from about -40 microcoulombs per gram to about +40 microcoulombs per gram.
- 20. A process for the preparation of carrier particles with substantially stable conductivity parameters, which comprises (1) mixing carrier cores with a first polymer pair and a second polymer pair and wherein the first and second polymer pair contains an insulating polymer and a conductive polymer; (2) dry mixing the carrier core particles and the polymer mixtures for a sufficient period of time enabling the polymer mixture to adhere to the carrier core particles; (3) heating the mixture of carrier core particles and polymer mixture to a temperature of between about 200.degree. F. and about 550.degree. F., whereby the polymer mixture melts and fuses to the carrier core particles; and (4) thereafter cooling the resulting coated carrier particles.
- 21. A process in accordance with claim 20 wherein the carrier core is steel, iron and ferrites.
- 22. A process in accordance with claim 20 wherein the resulting carrier particles are of a conductivity of from about 10.sup.-6 mho-cm.sup.-1 to about 10.sup.-15 mho-cm.sup.-1.
- 23. A process in accordance with claim 20 wherein the triboelectric charging value of the resulting carrier particles is from about -40 microcoulombs per gram to about a positive 40 microcoulombs per gram.
- 24. A process in accordance with claim 20 wherein the coating is continuous, and is present in a thickness of from about 0.2 micron to about 1.5 microns.
- 25. A process in accordance with claim 20 wherein the polymer mixture is heated for a period of from about 10 minutes to about 60 minutes.
- 26. A process in accordance with claim 20 wherein the carrier core particles have an average particle diameter of between about 30 microns and about 200 microns.
- 27. A process in accordance with claim 20 wherein the carrier core has a surface area of at least 200 cm.sup.2 per gram, and up to 1,000 cm.sup.2 per gram.
- 28. A process in accordance with claim 20 wherein the polymer mixture adheres to the carrier core particles by impaction or by electrostatic attraction.
- 29. A process in accordance with claim 20 wherein the polymers in each pair are dissimilar.
- 30. A process for the preparation of conductive carrier particles consisting of essentially of mixing a carrier core with a first polymer and a second polymer pair; heating the mixture; and cooling the mixture; and wherein the first polymer is insulating and the second polymer pair contains an insulating polymer and a conductive polymer; and wherein the carrier conductivity thereof is from about 10.sup.-6 to about 10.sup.-14 (ohm-cm).sup.-1.
- 31. A process in accordance with claim 30 wherein the first polymer is polymethylacrylate and the second polymer pair is comprised of polyvinylidene fluoride and polyvinylidene fluoride with a conductive component.
- 32. A process in accordance with claim 30 wherein the first polymer is polyvinylidene fluoride, and the second polymer pair is comprised of polymethylmethacrylate and polymethylacrylate with a conductive component.
- 33. A process in accordance with claim 31 wherein the conductive component is carbon black.
- 34. A process in accordance with claim 32 wherein the conductive component is carbon black.
- 35. A process in accordance with claim 34 wherein the carbon black is present in an amount of from about 10 to about 40 weight percent.
- 36. A process in accordance with claim 30 wherein the carrier core is comprised of steel, iron, or ferrites.
- 37. A process in accordance with claim 30 wherein the triboelectric charging value of the resulting carrier particles is from about -40 microcoulombs per gram to about a positive 40 microcoulombs per gram.
- 38. A process in accordance with claim 30 wherein the coating is continuous, and is present in a thickness of from about 0.2 micron to about 1.5 microns; and wherein the polymer mixture is heated for a period of about 10 minutes to about 60 minutes.
- 39. A process in accordance with claim 1 wherein the polymers of each pair are chemically dissimilar.
- 40. A process in accordance with claim 1 wherein four carrier cores are selected.
- 41. A process for the preparation of carrier particles consisting essentially of mixing carrier cores with a first polymer pair and a second polymer pair; heating the mixture; and cooling the mixture; and wherein the first and second polymer pair each contain an insulating polymer and a conductive polymer, and wherein said first polymer pair and said second polymer pair are triboelectrically dissimilar.
- 42. A process for the preparation of conductive carrier particles consisting of mixing carrier core particles with a first polymer pair and a second polymer pair wherein the first polymer pair contains an insulating polymer and a conductive polymer, and the second polymer pair contains an insulating polymer and a conductive polymer, wherein the conductive polymer contains dispersed therein a conductive component, and wherein the conductivity of the resulting carrier particles is from about 10.sup.-6 to about 10.sup.-4 (ohm-cm).sup.-1.
- 43. A process in accordance with claim 42 wherein the first polymer pair is comprised of an insulating polymethylmethacrylate and a conductive polymethylmethacrylate, and the second polymer pair is comprised of an insulating polyvinylidene fluoride and a conductive polyvinylidene fluoride.
Parent Case Info
This is a division of application Ser. No. 08/373,715, filed Jan. 17, 1995 pending.
US Referenced Citations (2)
Number |
Name |
Date |
Kind |
5102769 |
Creatura |
Apr 1992 |
|
5230980 |
Maniar |
Jul 1993 |
|
Divisions (1)
|
Number |
Date |
Country |
Parent |
373715 |
Jan 1995 |
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