Waterborne polyurethane coating compositions

• US 8,343,601 B1
• Filed: 07/06/2011
• Issued: 01/01/2013
• Est. Priority Date: 07/06/2011
• Status: Active Grant

• Current Assignee: Covestro Deutschland AG
• Original Assignee: Bayer Materialscience AG (Covestro AG), Bayer Materialscience LLC (Covestro AG)
• Inventors: Ekin, Abdullah, Stewart, Raymond, Subramanian, Ramesh, Pohl, Torsten
• Primary Examiner(s): Miggins, Michael C
• Application Number:
  US13/176,911
• Publication Number:
  US 20130011591A1
• Time in Patent Office: 545 Days
• Field of Search: 524/832, 524/819, 524/456, 524/589, 524/590, 524/839, 428/34.4, 428/34.6, 428/34.7
• US Class Current: 428/34.7
• CPC Class Codes: C03C 17/322 Polyurethanes or polyisocyanates
• CPC Class Codes: C08L 61/20 Condensation polymers of aldehydes or ketones with only compounds containing hydrogen attached to nitrogen with aminophenols C08L61/04
• CPC Class Codes: C09D 133/14 of esters containing halogen, nitrogen, sulfur or oxygen atoms in addition to the carboxy oxygen
• CPC Class Codes: C09D 175/06 from polyesters
• CPC Class Codes: Y10T 428/131 Glass, ceramic, or sintered, fused, fired, or calcined metal oxide or metal carbide containing [e.g., porcelain, brick, cement, etc.]
• CPC Class Codes: Y10T 428/1317 Multilayer [continuous layer]
• CPC Class Codes: Y10T 428/1321 Polymer or resin containing [i.e., natural or synthetic]
• CPC Class Codes: Y10T 428/31601 Quartz or glass

Abstract

Aqueous polyurethane coating compositions are disclosed in this specification. The aqueous polyurethane coating compositions contain a polycarbonate-polyurethane resin component, an aminoplast resin component, and a polyacrylic polyol component.

Claims

1. An aqueous polyurethane coating composition comprising:

(a) a water-dilutable hydroxy-functional polyacrylic resin comprising a reaction product of;

(A1) an olefinically unsaturated hydroxy-functional monomer;

(A2) an olefinically unsaturated monomer that comprises an ionic group or a potentially ionic group; and

(A3) an olefinically unsaturated monomer that does not comprise an ionic group, a potentially ionic group, or a hydroxyl group;

(b) a water-dilutable aminoplast resin; and

(c) a water-dilutable polycarbonate-polyurethane resin,

wherein the polycarbonate-polyurethane resin is non-functional.

2. The aqueous polyurethane coating composition of claim 1, wherein the hydroxy-functional polyacrylic resin component (a) has a weight average molecular weight of 500-100000, a hydroxyl number of 16.5 to 264 mg KOH/g and an acid number of 5 to 125 mg KOH/g.

3. The aqueous polyurethane coating composition of claim 1, wherein the aminoplast resin component (b) comprises a melamine-formaldehyde condensation product.

4. The aqueous polyurethane coating composition of claim 1, wherein the polycarbonate-polyurethane resin component (c) is characterized by a glass transition temperature of between −

60°

C. and 0°

C.

5. The aqueous polyurethane coating composition of claim 1, wherein the polycarbonate-polyurethane resin component (c) is characterized by a viscosity at 25°

C. of less than 500 mPa·

s in an 38% to 42% solids aqueous dispersion.

6. The aqueous polyurethane coating composition of claim 1, further comprising an additional polyol resin selected from the group consisting of water-dispersible hydroxy-functional polyester resins and water-dispersible hydroxy-functional polyether-polyurethane resins.

7. A glass substrate at least partially coated with the coating composition of claim 1.

8. A glass container at least partially coated with the coating composition of claim 1.

9. The aqueous polyurethane coating composition of claim 1, wherein the aminoplast resin component (b) comprises an oligomeric methylated melamine-formaldehyde condensation product comprising imino groups, methoxymethyl groups, and methylol groups.

10. The aqueous polyurethane coating composition of claim 9, wherein an equivalent ratio of methylol groups and alkoxylmethyl groups of component (b) to hydroxyl groups of component (a) is at least 0.05:

1.

11. The aqueous polyurethane coating composition of claim 1, wherein the polycarbonate-polyurethane resin component (c) comprises a reaction product of a polycarbonate polyol and a polyisocyanate selected from the group consisting of 4,4′

-diisocyanatodicyclohexylmethane, isophorone diisocyanate, 1,6-hexamethylene diisocyanate, and 1-methyl-2,4(2,6)-diisocyanatocyclohexane.

12. The aqueous polyurethane coating composition of claim 11, wherein the polycarbonate polyol has a number average molecular weight range 500 to 6000.

13. The aqueous polyurethane coating composition of claim 1, comprising:

99% to 1% by weight on a solids basis of the water-dilatable hydroxy-functional polyacrylic resin and a water-dilutable aminoplast resin; and

1% to 99% by weight on a solids basis of the water-dilutable polycarbonate-polyurethane resin

wherein the weight percents total 100% by weight.

14. The aqueous polyurethane coating composition of claim 13, comprising:

40% to 90% by weight on a solids basis of the water-dilutable hydroxy-functional polyacrylic resin;

a water-dilutable aminoplast resin; and

60% to 10% by weight on a solids basis of the water-dilutable polycarbonate-polyurethane resin

wherein the weight percents total 100% by weight.

15. The aqueous polyurethane coating composition of claim 1, wherein the weight ratio on a solids basis of the hydroxy-functional polyacrylic resin to the aminoplast resin is from 55:

45 to 85;

15.

16. The aqueous polyurethane coating composition of claim 15, wherein the weight ratio on a solids basis of the hydroxy-functional polyacrylic resin to the aminoplast resin is from 60:

40 to 70;

30.

17. The aqueous polyurethane coating composition of claim 1, further comprising a silane-functional adhesion promoter.

18. The aqueous polyurethane coating composition of claim 17, wherein the adhesion promoter is selected from the group consisting of γ

-mercaptopropyl-trimethoxysilane, 3-aminopropyltriethoxysilane, 3-aminopropylsilane hydrolysate, 3-glycidyloxypropyltriethoxysilane, and combinations of any thereof.

19. A substrate at least partially coated with the coating composition of claim 1.

20. The substrate of claim 19, wherein the coating exhibits microhardness of no greater than 90 N/mm², direct impact strength of at least 60 in-lbs, and reverse impact strength of at least 20 in-lbs.