Coating compositions with modified particles and methods of using the same

• US 20030224174A1
• Filed: 06/03/2002
• Published: 12/04/2003
• Est. Priority Date: 06/03/2002
• Status: Active Grant

• Current Assignee: PPG Industries Ohio Incorporated (Nouryon BV)
• Original Assignee: PPG Industries Ohio Incorporated (Nouryon BV)
• Inventors: Carney, Joseph M., Poindexter, Laura E., White, Michael L., Anderson, Lawrence G., Hockswender, Thomas R., Simpson, Dennis A., Sadvary, Richard J., White, Daniela, Tyebjee, Shiryn, Schneider, John R., Mayo, Michael A., OʼDwyer, James B.
• Granted Patent: US 6,790,904 B2
• Time in Patent Office: Days
• US Class Current: 428/413
• CPC Class Codes: C08K 3/22 of metals
• CPC Class Codes: C08K 3/28 Nitrogen-containing compounds
• CPC Class Codes: C08K 3/36 Silica
• CPC Class Codes: C08K 9/06 with silicon-containing compounds
• CPC Class Codes: C09D 7/62 modified by treatment with other compounds
• CPC Class Codes: C09D 7/67 Particle size smaller than 100 nm
• CPC Class Codes: C09D 7/68 Particle size between 100-1000 nm
• CPC Class Codes: C09D 7/69 Particle size larger than 1000 nm
• CPC Class Codes: Y10T 428/31511 Of epoxy ether

Abstract

Liquid coating compositions having improved mar and scratch resistance are disclosed. The coatings generally comprise one or more particles that have been modified to render the particles more surface active. The improved resistance is achieved without affecting the appearance or mechanical performance of the coatings. Methods for using the coatings, and the substrates coated therewith, are also disclosed.

Claims

1. A liquid coating comprising:

a) a film-forming resin; and

b) a plurality of particles dispersed in said resin, wherein the particles have been chemically modified to have a surface tension lower than that of the film-forming resin as cured without particles.

2. The coating composition of claim 1, wherein the particles have been modified by attachment of a compound having the structure:

F—

L—

Z

wherein F is a moiety comprising a functional group;

Z is a moiety that decreases the surface tension of the particle to which it is attached; and

L is a group that links F and Z.

3. The coating composition of claim 2, wherein L comprises the reaction product of an epoxy and an amine.

4. The coating composition of claim 2, wherein L comprises the reaction product of an epoxy and a carboxylic acid.

5. The coating composition of claim 4, wherein the carboxylic acid is stearoyl sarcosine.

6. The coating composition of claim 2, wherein L comprises the reaction product of an epoxy and an alcohol.

7. The coating composition of claim 2, wherein L comprises the reaction product of an amine and an isocyanate.

8. The coating composition of claim 2, wherein L comprises the reaction product of an amine and a carboxylic acid.

9. The coating composition of claim 2, wherein L comprises the reaction product of an isocyanate and an alcohol.

10. The coating composition of claim 2, wherein L comprises the reaction product of an acrylate and an amine.

11. The coating composition of claim 1, wherein said particles are modified through the attachment of a compound having the structure:

Si(OR)₃—

(CH₂)_n—

Z

wherein R is an alkyl group having 1 to 30 carbons;

n is 0, 1 or 2; and

Z is a moiety that decreases the surface tension of the particle to which it is attached.

12. The coating composition of claim 11, wherein Z comprises a long chain alkyl group.

13. The coating composition of claim 11, wherein Z comprises a fluorocarbon.

14. The coating composition of claim 11, wherein Z comprises a silane to which is attached at least two methyl groups.

15. The coating composition of claim 12, wherein Z is —

(CH₂)_n1—

CH₃;

wherein n₁ is 1 to 30; and

wherein the total of n and n₁ is 3 or greater.

16. The coating composition of claim 15, wherein n₁ is 7 to 17.

17. The coating composition of claim 12, wherein Z is

18. The coating composition of claim 13, wherein Z is —

(CF₂)_m—

CF₃, wherein m is 0 to 30.

19. The coating composition of claim 18, wherein m is 7.

20. The coating composition of claim 14, wherein Z is —

(CH₂)_n3—

(Si(CH₃)₂—

O)_m1—

Si(CH₃)₃; and

wherein n₃ is 0 to 17 and m₁ is 1 to 50.

21. The coating composition of claim 20, wherein n₃ is 0 to 4 and m₁ is 1 to 10.

22. The coating composition of claim 1, wherein the surface tension of said modified particles is 50 dynes/cm or less.

23. The coating composition of claim 22, wherein the surface tension of said modified particles is 40 dynes/cm or less.

24. The coating composition of claim 1, wherein there is a greater concentration of particles in the surface region than the bulk region.

25. The coating composition of claim 1, wherein the particles are evenly distributed between the surface and bulk regions.

26. The coating of claim 1, wherein said inorganic particles are selected from silica, alumina, alkali alumina silicate, borosilicate glass, nitrides, oxides, quartz, nepheline syenite, zircon, buddeluyite, and eudialyte.

27. The coating of claim 26, wherein said silica is crystalline silica, amorphous silica, fumed silica, precipitated silica or mixtures thereof.

28. The coating of claim 1, wherein the particles are nanoparticles having an average particle size of between 2.0 and 500 nanometers.

29. The coating of claim 28, wherein the average particle size ranges between 5 and 200 nanometers.

30. The coating of claim 1, wherein the particles are microparticles having an average particle size of between 0.5 and 50 microns.

31. The coating of claim 30, wherein the average particle size ranges between 0.5 and 10.

32. The coating of claim 1, wherein the weight percent of the particles is less than 20, with weight percent based on total weight of the composition.

33. The coating of claim 32, wherein the weight percent is between 0.01 and 10.

34. The coating of claim 33, wherein the weight percent is between 0.01 and 8.

35. The coating of claim 11, wherein the Z moiety has no functional groups.

36. A substrate coated with the coating of claim 1.

37. The substrate of claim 36, wherein said substrate is metallic.

38. The substrate of claim 36, wherein said substrate is polymeric.

39. The substrate of claim 36, wherein one or more additional layers are disposed between the substrate and the coating.

40. A method for improving scratch and/or mar resistance of a coated substrate comprising applying to at least a portion of the substrate the coating of claim 1.

41. The method of claim 40, wherein at least an intervening layer is applied to said substrate prior to application of the coating.

42. The coating composition of claim 1, wherein the coating, when cured and subjected to mar and/or scratch testing, has a greater 20 degree gloss retention as compared to no particle being present.

43. The coating composition of claim 42, wherein the 20 degree gloss retention after mar and/or scratch testing is 20 percent or greater.

44. The coating composition of claim 42, wherein the 20 degree gloss retention after mar and/or scratch testing is 50 percent or greater.

45. The coating composition of claim 42, wherein the 20 degree gloss retention after mar and/or scratch testing is 70 percent or greater.

48. A substrate coated with a first coating of claim 1 and a second coating of claim 1, wherein the first and second coatings are different.

49. The coating composition of claim 43, wherein the cured coating has a flexibility of at least 6 at a temperature of 70°

F.

50. The coating composition of claim 49, wherein the cured coating has a flexibility of at least 8 at temperature of 70°

F.

51. The coating composition of claim 44, wherein the cured coating has a flexibility of at least 6 at a temperature of 70°

F.

52. The coating composition of claim 51, wherein the cured coating has a flexibility of at least 8.

53. The coating composition of claim 45, wherein the cured coating, has a flexibility of at least 6 at a temperature of 70°

F.

54. The coating composition of claim 53, wherein the cured coating has a flexibility of at least 8.

58. The liquid coating composition of claim 1, wherein the coating is a 1K system.

59. The liquid coating composition of claim 1, wherein the coating is a 2K system.

60. The liquid coating composition of claim 59, wherein the resin pack further comprises an aminoplast.

61. The liquid coating composition of claim 60, wherein the aminoplast is melamine.

46. A coating composition comprising:

a) a film-forming resin; and

b) a plurality of particles dispersed in said resin, wherein the particles have been modified such that they lower the surface tension of the film-forming resin.

47. A method for lowering the surface tension of a cured coating comprising adding to the uncured liquid coating composition a particle having a lower surface tension that the cured coating has without the addition of the particle.

55. A cured coating having a gloss retention after mar and/or scratch testing of 38 percent or greater and a flexibility of 6 or greater at a temperature of 70°

F.

56. The cured coating of claim 55 having a gloss retention after mar and/or scratch testing of 55 percent or greater and a flexibility of 8 or greater.

57. The cured coating of claim 55 having a gloss retention after mar and/or scratch testing of 75 percent or greater and a flexibility of 8 or greater.