Method and a composition for producing an undercoat layer using dialkyl malonate blocked isocyanates (for electrophotographic applications)

• US 20060009576A1
• Filed: 07/09/2004
• Published: 01/12/2006
• Est. Priority Date: 07/09/2004
• Status: Active Grant

• Current Assignee: Eastman Kodak Company
• Original Assignee: Eastman Kodak Company
• Inventors: Molaire, Michel F.
• Granted Patent: US 7,937,023 B2
• Time in Patent Office: Days
• US Class Current: 524/839
• CPC Class Codes: C08G 18/6212 Polymers of alkenylalcohols; Acetals thereof; Oxyalkylation products thereof
• CPC Class Codes: C08G 18/7831 containing biuret groups
• CPC Class Codes: C08G 18/8093 Compounds containing active methylene groups
• CPC Class Codes: C08K 3/22 of metals
• CPC Class Codes: C09D 175/04 Polyurethanes
• CPC Class Codes: Y10T 428/25 Web or sheet containing structurally defined element or component and including a second component containing structurally defined particles

Abstract

A method and a composition for the production of surface smoothing polyurethane layers for application to a substrate prior to subsequent application of a charge generation layer for electrophotographic applications by preparing a coating solution containing a dialkyl malonate capped isocyanate or polyisocyanate, a polyol and at least one finely-divided metal oxide, coating the substrate with the coating solution and heating the coating solution to a temperature up to about 140° C.

Claims

1. A method for coating an electrophotographic process element with a conductive surface smoothing polyurethane layer;

the method comprising;

a) producing a coating solution comprising a dialkyl malonate capped isocyanate or polyisocyanate, a polyol and at least one finely divided metal oxide or mixtures thereof;

b) coating the substrate with the coating solution to produce a coated substrate; and

,

c) heating the coated substrate at a temperature up to about 140°

C.

2. The method of claim 1, wherein the element comprises a seamless metallic sleeve.

3. The method of claim 1, wherein the element comprises a seamless nickel sleeve.

4. The method of claim 1, wherein the element comprises a seamless plastic sleeve.

5. The method of claim 1, wherein the element comprises a photoelectric film.

6. The method of claim 1, wherein the dialkyl malonate is diethyl malonate.

7. The method of claim 1, wherein the coating solution contains a monofunctional alcohol.

8. The method of claim 1, wherein the dialkyl malonate contain the alkyl groups containing from 1 to about 12 carbon atoms.

9. The method of claim 8, wherein the alkyl groups contain from 2 to about 6 carbon atoms.

10. The method of claim 8, wherein the alkyl groups of the dialkyl malonate are the same.

11. The method of claim 8, wherein the alkyl groups of the dialkyl malonate are different.

12. The method of claim 1, wherein the isocyanate moiety is hexamethylene diisocyanate biuret.

13. The method of claim 1, wherein the isocyanate moiety is isophorone triisocyanate.

14. The method of claim 1, wherein a mixture of DEM-blocked isophorone triisocyanate and DEM-blocked hexamethylene diisocyanate buret is used.

15. The method of claim 1, wherein the isocyanate and polyol are present in amounts sufficient to provide an OH group to NCO group ratio of from about 1 to about 1.0.

16. The method of claim 15, wherein the ratio is from about 1 to about 1.5.

17. The method of claim 1, where the polyol is a vinyl polymer made of 81 mole % vinyl chloride, 4-mole % vinyl acetate, 15-mole % hydroxy ethyl acrylate, and hydroxyl value of 59.

18. The method of claim 1, where the polyol is a mixture comprising a vinyl polymer made of 81 mole % vinyl chloride, 4 mole % vinyl acetate, 15 mole % hydroxy ethyl acrylate, and hydroxyl value of 59;

and three-fourth pentaerhytritol ethoxylated.

19. The method of claim 1, wherein the at least one finely divided metal oxide is selected from the group consisting of metal oxides of titanium, zirconium, indium, antimony, tin, aluminum and mixtures thereof.

20. The method of claim 19, wherein the at least one metal oxide is present in an amount equal to from about 40 to about 90 weight percent of the solids in the polyurethane layer.

21. The method of claim 20, wherein the amount is from about 60 to 80 weight percent.

22. The method of claim 1, wherein the finely divided metal oxide comprises particles of a size less than about 0.1 micron.

23. The method of claim 22, wherein the size is from about 10 to about 50 nanometers.

24. The method of claim 1, wherein the polyurethane layer has a thickness of at least 2 microns.

25. The method of claim 24, wherein the thickness is greater than about 10 microns.

26. The method of claim 7, wherein the mono-functional alcohol is present in an amount from about 10 to about 25-weight percent monofunctional alcohol based upon the weight of the coating solution.

27. A coating composition for depositing a conductive surface smoothing coating on an electrophotographic process element, the composition comprising:

a dialkyl malonate capped isocyanate or polyisocyanate, a polyol and at least one finely-divided metal oxide.

28. The composition of claim 27, wherein the dialkyl malonate is diethyl malonate.

29. The composition of claim 27, wherein the alkyl groups contain from 1 to about 12 carbon atoms.

30. The composition of claim 27, wherein the ratio is from about 1 to about 1.5.

31. The composition of claim 27, wherein the coating solution contains at least one finely divided metal oxide.

32. The composition of claim 27, wherein the composition contains a monofunctional alcohol.

33. The composition of claim 27, wherein the at least one metal oxide is selected from the group consisting of metal oxides of titanium, zirconium, indium, antimony, tin, aluminum and mixtures thereof.

34. The composition of claim 27, wherein the at least one metal oxide is present in an amount equal to from about 40 to about 90 weight percent of the solids in the polyurethane layer.

35. The composition of claim 33, wherein the finely divided metal oxide comprises particles of a size less than about 0.1 micron.

36. The composition of claim 32, wherein the monofunctional alcohol is present in an amount from about 10 to about 25 weight percent mono-functional alcohol based upon the weight of the coating solution.

37. The composition of claim 27, wherein the polyol is a vinyl polymer made of 81 mole % vinyl chloride, 4-mole % vinyl acetate, 15-mole % hydroxy ethyl acrylate, and hydroxyl value of 59.

38. The composition of claim 27, wherein the polyol is a mixture comprising a vinyl polymer made of 81 mole % vinyl chloride, 4-mole % vinyl acetate, 15-mole % hydroxy ethyl acrylate, and hydroxyl value of 59;

and a pentaerhytritol ethoxylated 3/4.