Weldable coating compositions having improved intercoat adhesion

• US 6,641,923 B2
• Filed: 07/31/2001
• Issued: 11/04/2003
• Est. Priority Date: 07/31/2001
• Status: Expired due to Fees

• Current Assignee: PPG Industries Ohio Incorporated (Nouryon BV)
• Original Assignee: PPG Industries Ohio Incorporated (Nouryon BV)
• Inventors: Anderson, Lawrence G., Sadvary, Richard J., Jones, Dennis W., Gaggini, Sherry M.
• Primary Examiner(s): Dawson, Robert
• Assistant Examiner(s): Keehan, Christopher M
• Application Number:
  US09/919,213
• Publication Number:
  US 20030064256A1
• Time in Patent Office: 826 Days
• Field of Search: 524/2, 524/414, 524/612, 528/4, 528/5, 528/8, 528/13, 525/100, 525/101, 525/107, 525/113, 525/124, 428/413, 428/416, 428/447
• US Class Current: 428/447
• CPC Class Codes: B23K 35/226 Non-corrosive coatings; Primers applied before welding
• CPC Class Codes: C08G 59/304 containing phosphorus
• CPC Class Codes: C08G 77/56 Boron-containing linkages C08G77/485 takes precedence
• CPC Class Codes: C08K 5/0041 Optical brightening agents, organic pigments
• CPC Class Codes: C08K 5/55 Boron-containing compounds C08K5/0091 takes precedence
• CPC Class Codes: C08L 2666/28 Non-macromolecular organic substances
• CPC Class Codes: C08L 2666/54 Inorganic substances
• CPC Class Codes: C08L 83/00 Compositions of macromolecular compounds obtained by reactions forming in the main chain of the macromolecule a linkage containing silicon with or without sulfur, nitrogen, oxygen or carbon only; Compositions of derivatives of such polymers
• CPC Class Codes: C09D 163/00 Coating compositions based on epoxy resins; Coating compositions based on derivatives of epoxy resins
• CPC Class Codes: C09D 167/00 Coating compositions based on polyesters obtained by reactions forming a carboxylic ester link in the main chain based on polyester-amides C09D177/12; based on polyester-imides C09D179/08; Coating compositions based on derivatives of such polymers
• CPC Class Codes: C09D 5/08 Anti-corrosive paints
• CPC Class Codes: C09D 5/24 Electrically-conducting paints conductive materials H01B1/00
• CPC Class Codes: Y10T 428/31511 Of epoxy ether
• CPC Class Codes: Y10T 428/31522 Next to metal
• CPC Class Codes: Y10T 428/31663 As siloxane, silicone or silane

Abstract

A weldable curable coating composition with improved intercoat adhesion is disclosed comprising a resinous binder comprising a polymer (A) with functional groups and a crosslinking agent with functional groups reactive with those of polymer (A); an electroconductive pigment; and an adhesion promoting compound comprising boron containing compounds. In an alternative embodiment, the adhesion promoting compound may comprise siloxane polymer reacted with aluminates, titanates, zirconates, silicates, siloxanes, silanes, and mixtures thereof, wherein each component is different.

Claims

1. A thermosetting coating composition comprising:

(A) a resinous binder comprising;

(1) at least one functional group-containing polymer, and

(2) at least one curing agent having functional groups reactive with the functional groups of (1);

(B) at least one electroconductive pigment dispersed in resinous binder (A), said pigment selected from at least one of zinc, ferrophosphorus, and tungsten; and

(C) at least one boron-containing compound selected from boric acid, boric acid equivalents, and mixtures thereof, wherein each component is different, and wherein said boron-containing compound comprises a reaction product formed from the following reactants;

(1) at least one polysiloxane comprising at least one of the following structural units (I);

2. The thermosetting coating composition of claim 1 wherein the electroconductive pigment (B) is dispersed in the resinous binder (A) such that the weight ratio of (B) to (A) is within the range of 0.5 to 9.0:

1, the thermosetting coating composition being characterized such that when deposited and cured on said metal substrate, the cured coating is weldable.

3. The thermosetting coating composition of claim 1 wherein at least one R² comprises OH.

4. The thermosetting coating composition of claim 1, wherein said polysiloxane comprises one or more ungelled organic polysiloxanes having reactive functional groups, said polysiloxane having the following structure (II) or (III):

where m has a value of at least 1;

m′

ranges from 0 to 75;

n ranges from 0 to 75;

n′

ranges from 0 to 75;

each R, which may be identical or different, is selected from of H, OH, monovalent hydrocarbon groups, monovalent siloxane groups and mixtures thereof of any of the foregoing; and

R^a comprises the following structure (IV);

5. The thermosetting coating composition of claim 4, wherein the polysiloxane is a reaction product formed from the following reactants:

(A) a silicon hydride-containing polysiloxane having the following structure (V);

wherein the R groups are selected from H, OH, monovalent hydrocarbon groups, siloxane groups and mixtures thereof, wherein at least one of the groups represented by R is H, and n′

ranges from 0 to 100, such that the mole percent of hydrogen-bonded silicon atoms to non-hydrogen-bonded silicon atoms ranges from 10 to 100 percent; and

(B) one or more hydroxyl functional materials comprising at least one primary hydroxyl group and at least one unsaturated bond capable of undergoing hydrosilylation reaction.

6. The thermosetting coating composition of claim 5, wherein reactant (B) is a hydroxyl functional group-containing allyl ether selected from trimethylolpropane monoallyl ether, pentaerythritol monoallyl ether, trimethylolpropane diallyl ether and mixtures thereof;

or an allyl alcohol.

7. The thermosetting coating composition of claim 1, wherein the functional group-containing polymer (1) is selected from at least one of an epoxy group-containing polymer, and a polyester polymer.

8. The thermosetting coating composition of claim 7 wherein the functional group-containing polymer comprises an epoxy group-containing polymer.

9. The thermosetting coating composition of claim 8, wherein the functional group-containing polymer comprises a phosphatized epoxy group-containing polymer.

10. The thermosetting coating composition of claim 7 wherein the functional group-containing polymer comprises a polyester polymer.

11. The thermosetting coating composition of claim 10, wherein the functional group-containing polymer comprises a phosphatized polyester polymer.

12. The thermosetting coating of claim 1, wherein the functional group-containing polymer comprises a reaction product of an epoxy group-containing polymer

and a compound containing phosphorous acid groups, the reaction product having reactive functional groups.

13. The thermosetting coating composition of claim 1, wherein the curing agent (2) is selected from at least one of a blocked isocyanate, an aminoplast resin, a carboxylic acid, a polyol, a polyamine.

14. The thermosetting coating composition of claim 13, wherein the curing agent (2) comprises at least one aminoplast resin.

15. The thermosetting coating composition of claim 13, wherein the functional groups of the curing agent (2) comprise at least one blocked isocyanate.

16. The thermosetting coating composition of claim 13, wherein the functional group-containing curing agent (2) comprises at least one blocked isocyanate and at least one aminoplast resin.

53. A substrate coated with the thermosetting coating composition of claim 1.

54. The substrate of claim 53, wherein the substrate is selected from steel, cold rolled steel, electrogalvanized steel, hot dip galvanized steel, galvaneal steel, galvalume steel, aluminum.

63. The thermosetting coating composition of claim 1, wherein the electroconductive pigment (B) comprises zinc.

64. The thermosetting coating composition of claim 1, wherein the electroconductive pigment (B) comprises ferrophosphorus.

65. The thermosetting coating composition of claim 1, wherein the electroconductive pigment (B) comprises tungsten.

17. A thermosetting coating composition comprising:

(A) a resinous binder comprising;

(1) at least one epoxy group-containing polymer, and

(2) at least one curing agent selected from a blocked isocyanate and an aminoplast resin; and

(B) at least one electroconductive pigment selected from at least one of zinc, ferrophosphorus, and tungsten dispersed in resinous binder (A) such that the weight ratio of (B) to (A) is within the range of 1 to 6.0;

1, and

(C) at least one boron-containing compound selected from boric acid, boric acid equivalents, and mixtures thereof, wherein the boron-containing compound (C) comprises a reaction product formed from the following reactants;

(1) at least one polysiloxane comprising at least one of the following structural units (I);

18. The thermosetting coating composition of claim 17, wherein the resinous binder (A) further comprises at least one catalyst selected from at least one of dibutyl tin dilaurate, dibutyl tin oxide, dibutyl tin diacetate, phosphoric acid, alkyl acid phosphate, and carboxylic acid.

19. The thermosetting coating composition of claim 17 which further comprises a corrosion inhibitive pigment dispersed in resinous binder (A) such that the weight ratio of the corrosion inhibitive pigment to (A) is within the range of 0.1 to 0.7.

24. The thermosetting coating composition of claim 17 wherein the boron-containing compound (C) comprises a polysiloxane borate ester.

25. The thermosetting coating composition of claim 24, wherein the boron-containing compound (C) is present in an amount sufficient to provide an amount of boron ranging from 0.001% to 5% based on total weight of resin solids present in the composition.

55. A substrate coated with the thermosetting coating composition of claim 17.

56. The substrate of claim 55, wherein the substrate is selected from steel, cold rolled steel, electrogalvanized steel, hot dip galvanized steel, galvaneal steel, galvalume steel, aluminum.

20. A thermosetting coating composition comprising:

(A) a resinous binder comprising;

(1) at least one phosphatized epoxy group-containing polymer, and

(2) at least one curing agent selected from at least one of a blocked isocyanate and an aminoplast resin;

(B) at least one electroconductive pigment selected from at least one of zinc, ferrophosphorus, and tungsten dispersed in resinous binder (A) such that the weight ratio of (B) to (A) is within the range of 1.0 to 6.0;

1, and

(C) at least one boron-containing compound selected from boric acid, boric acid equivalents, and mixtures thereof,

wherein each component is different, the thermosetting coating composition being characterized such that when deposited and cured on said metal substrate, the cured coating is weldable.

21. The thermosetting coating composition of claim 20 wherein the boron-containing compound (C) comprises a reaction product formed from the following reactants:

(A) at least one polysiloxane comprising at least one of the following structural units (I);

22. The thermosetting coating composition of claim 20, wherein the resinous binder (A) further comprises at least one catalyst selected from at least one of dibutyl tin dilaurate, dibutyl tin oxide, dibutyl tin diacetate, phosphoric acid, alkyl acid phosphate, and carboxylic acid.

23. The thermosetting coating composition of claim 20 which further comprises a corrosion inhibitive pigment dispersed in resinous binder (A) such that the weight ratio of the corrosion inhibitive pigment to (A) is within the range of 0.1 to 0.7.

26. A multilayer composite coating comprising a weldable primer coating formed over at least a portion of a substrate, the primer coating formed from a primer film-forming composition and a topcoat over at least a portion of the primer coating, the topcoat formed from a topcoat film-forming composition, wherein the primer film forming composition comprises:

(A) a resinous binder comprising;

(1) a functional group-containing polymer, and

(2) a curing agent having functional groups reactive with the functional groups of (1);

(B) an electroconductive pigment dispersed in resinous binder (A) such that the weight ratio of (B) to (A) is within the range of 0.5 to 9.0;

1,the cured coating is weldable, and

(C) at least one boron-containing compound selected from boric acid, boric acid equivalents, and mixtures thereof, wherein the boron containing compound (C) of the primer film forming composition comprises the reaction product of the following reactants;

(1) a polysiloxane comprising at least one of the following structural units (I);

27. The multilayer composite coating of claim 26, wherein at least one of the R² comprises OH.

28. The multilayer coating composition of claim 26, wherein said polysiloxane (1) comprises one or more ungelled organic polysiloxanes having reactive functional groups, said polysiloxane having the following structure (II) or (III):

where m has a value of at least 1;

m′

ranges from 0 to 50;

n ranges from 0 to 50;

R is independently selected from of H, OH, monovalent hydrocarbon groups, siloxane groups and mixtures thereof connected to the silicon atoms; and

R^a comprises the following structure (IV);

29. The multilayer coating composition of claim 28, wherein the polysiloxane (1) is the reaction product of the following reactants:

(A) a silicon hydride-containing polysiloxane having the following structure (V);

wherein the R groups are selected from H, OH, monovalent hydrocarbon groups, siloxane groups and mixtures thereof, wherein at least one of the groups represented by R is H, and n′

ranges from 0 to 100, such that the mole percent of hydrogen-bonded silicon atoms to non-hydrogen-bonded silicon atoms ranges from 10 to 100 percent; and

(B) one or more hydroxyl functional materials comprising at least one primary hydroxyl group and at least one unsaturated bond capable of undergoing hydrosilylation reaction.

30. The multilayer coating composition of claim 29, wherein reactant (B) of the primer film-forming composition comprises a hydroxyl functional group-containing allyl ether selected from an allyl alcohol and at least one of trimethylolpropane monoallyl ether, pentaerythritol monoallyl ether, trimethylolpropane diallyl ether and mixtures thereof.

31. The multilayer coating composition of claim 26, wherein the functional group containing polymer (1) is selected from at least one of an epoxy group-containing polymer, a phosphatized epoxy group-containing polymer, a polyester polymer, and a phosphatized polyester polymer.

32. The multilayer coating composition of claim 26, wherein the functional group containing polymer (1) comprises at least one epoxy group-containing polymer.

33. The multilayer coating composition of claim 26, wherein the functional group containing polymer (1) comprises at least one phosphatized epoxy group-containing polymer.

34. The multilayer coating composition of claim 26, wherein the functional group containing polymer (1) comprises a polyester polymer.

35. The multilayer coating composition of claim 26, wherein the functional group containing polymer (1) comprises a phosphatized polyester polymer.

36. The multilayer coating composition of claim 26, wherein the functional group containing polymer (1) comprises a reaction product of an epoxy group-containing polymer and a compound containing phosphorous acid groups, the reaction product having reactive functional groups.

37. The multilayer coating composition of claim 26, wherein the curing agent (2) is selected from at least one of a blocked isocyanate, an aminoplast resin, a carboxylic acid, a polyol, and a polyamine.

38. The multilayer coating composition of claim 26, wherein the functional group containing curing agent (2) comprises at least one aminoplast resin.

39. The multilayer coating composition of claim 26, wherein the functional group containing curing agent (2) comprises at least one blocked isocyanate.

40. The multilayer coating composition of claim 26, wherein the functional group containing curing agent (2) comprises at least one blocked isocyanate and at least one aminoplast resin.

41. The multilayer coating composition of claim 26, wherein the electroconductive pigment (B) of the primer film forming layer composition comprises zinc.

42. The multilayer coating composition of claim 26, wherein the electroconductive pigment (B) of the primer film forming layer composition comprises ferrophosphorus.

43. The multilayer coating composition of claim 26, wherein the electroconductive pigment (B) of the primer film forming layer composition comprises tungsten.

44. A multilayer composite coating comprising a weldable primer coating formed over at least a portion of a substrate, the primer coating formed from a primer film-forming composition and a topcoat over at least a portion of the primer coating, the topcoat formed from a topcoat film-forming composition, wherein the primer film forming composition comprises:

(A) a resinous binder comprising;

(1) at least one epoxy group-containing polymer, and

(2) at least one curing agent selected from a blocked isocyanate (and an aminoplast resin;

(B) at least one electroconductive pigment dispersed in resinous binder (A) such that the weight ratio of (B) to (A) is within the range of 1.0 to 6.0;

1; and

(C) at least one boron-containing compound selected from boric acid, boric acid equivalents, and mixtures thereof, wherein the boron-containing compound (C) comprises a reaction product formed from the following reactants;

(1) at least one polysiloxane comprising at least one of the following structural units (I);

45. The multilayer coating composition of claim 44, wherein the resinous binder (A) further comprises at least one catalyst selected from dibutyl tin dilaureate, dibutyl tin oxide, dibutyl tin diacetate, phosphoric acid, alkyl acid phosphate, and carboxylic acid.

46. The multilayer coating composition of claim 44, wherein the resinous binder (A) further comprises a corrosion inhibitive pigment dispersed in a resinous binder (A) such that the weight ratio of the corrosion inhibitive pigment to (A) is within the range of 0.1 to 0.7.

51. The multilayer coating composition of claim 44, wherein the boron-containing (C) compound comprises a polysiloxane borate ester.

52. The multilayer coating composition of claim 44, wherein the boron-containing (C) compound is present in an amount sufficient to provide an amount of boron ranging from 0.001% to 5% based on total weight of resin solids present in the composition.

47. A multilayer composite coating comprising a weldable primer coating formed over at least a portion of a substrate formed from a primer film-forming composition and a topcoat over at least a portion of the primer coating from a topcoat film-forming composition, wherein the primer film forming composition comprises:

(A) a resinous binder comprising;

(1) at least one phosphatized epoxy group-containing polymer, and

(2) at least one curing agent selected from at least one of blocked isocyanate and aminoplast resin;

(B) at least one electroconductive pigment selected from at least one of zinc, ferrophosphorus, and tungsten dispersed in resinous binder (A) such that the weight ratio of (B) to (A) is within the range of 1.0 to 6.0;

1, and

(C) at least one boron-containing compound selected from boric acid, boric acid equivalents, and mixtures thereof,

wherein each component is different, the primer coating composition being characterized such that when deposited and cured on said substrate, the cured coating is weldable.

48. The multilayer coating composite of claim 47 wherein the boron-containing compound (C) a reaction product formed from the following reactants:

(A) at least one polysiloxane comprising at least one of the following structural units (I);

49. The multilayer coating composition of claim 47, wherein the resinous binder (A) further comprises at least one catalyst selected from dibutyl tin dilaureate, dibutyl tin oxide, dibutyl tin diacetate, phosphoric acid, alkyl acid phosphate, and carboxylic acid.

50. The multilayer coating composition of claim 47, wherein the resinous binder (A) further comprises a corrosion inhibitive pigment dispersed in a resinous binder (A) such that the weight ratio of the corrosion inhibitive pigment to (A) is within the range of 0.1 to 0.7.

57. A thermosetting coating composition comprising:

(A) a resinous binder comprising;

(1) at least one functional group-containing polymer, wherein the functional group-containing polymer comprises a phosphatized epoxy group-containing polymer, and

(2) at least one curing agent having functional groups reactive with the functional groups of (1);

(B) at least one electroconductive pigment dispersed in resinous binder (A); and

(C) at least one boric acid ester derivative selected from at least one of triethanolamine borate, mannitol borate, n-propanolamine borate, trimethylolpropane borate, glycerol borate, and mixtures thereof, wherein each component is different.

58. A thermosetting coating composition comprising:

(A) a resinous binder comprising;

(1) at least one functional group-containing polymer, wherein the functional group-containing polymer comprises a phosphatized epoxy group-containing polymer, and

(2) at least one curing agent having functional groups reactive with the functional groups of (1);

(B) at least one electroconductive pigment dispersed in resinous binder (A); and

(C) at least one boron-containing compound comprising a reaction product formed from the following reactants;

(1) at least one polysiloxane comprising at least one of the following structural units (I);

59. The thermosetting coating composition of claim 58 wherein at least one R² comprises OH.

60. The thermosetting coating composition of claim 58, wherein said polysiloxane comprises one or more ungelled organic polysiloxanes having reactive functional groups, said polysiloxane having the following structure (II) or (III):

where m has a value of at least 1;

m′

ranges from 0 to 75;

n ranges from 0 to 75;

n′

ranges from 0 to 75;

each R, which may be identical or different, is selected from of H, OH, monovalent hydrocarbon groups, monovalent siloxane groups and mixtures thereof of any of the foregoing; and

R^a comprises the following structure (IV);

61. The thermosetting coating composition of claim 60, wherein the polysiloxane is a reaction product formed from the following reactants:

(A) a silicon hydride-containing polysiloxane having the following structure (V);

wherein the R groups are selected from H, OH, monovalent hydrocarbon groups, siloxane groups and mixtures thereof, wherein at least one of the groups represented by R is H, and n′

ranges from 0 to 100, such that the mole percent of hydrogen-bonded silicon atoms to non-hydrogen-bonded silicon atoms ranges from 10 to 100 percent; and

(B) one or more hydroxyl functional materials comprising at least one primary hydroxyl group and at least one unsaturated bond capable of undergoing hydrosilylation reaction.

62. The thermosetting coating composition of claim 61, wherein reactant (B) is a hydroxyl functional group-containing allyl ether selected from trimethylolpropane monoallyl ether, pentaerythritol monoallyl ether, trimethylolpropane diallyl ether and mixtures thereof;

or an allyl alcohol.