Low foaming waterborne coating composition and use thereof

Patent metadata

Field	Value
Publication number	US-9587140-B2
Application number	US-201314379824-A
Country	US
Kind code	B2
Filing date	Jan 29, 2013
Priority date	Feb 21, 2012
Publication date	Mar 7, 2017
Grant date	Mar 7, 2017

Abstract

The present disclosure is directed to a waterborne coating composition having neutral pH that is low foaming and forms dry coating layer that has high hardness and high gloss. This disclosure is further directed to a coating composition comprising a crosslinking component comprising: (a) one or more alkylated melamines that are essentially unreactive to a polyisocyanate; and (b) a polyisocyanate. The coating composition can be particularly suitable for vehicle coatings and other industrial or consumer applications.

First claim

What is claimed is:

1. A process for forming a coating layer over a substrate, said process comprising the steps of:
A) providing a crosslinkable component comprising a film forming polymer having a crosslinkable functional group, wherein the crosslinkable functional group is a hydroxyl group, and wherein the crosslinkable component comprises in a range of from about 20% to about 80% of water, percent based on the total weight of the crosslinkable component;
B) providing a crosslinking component comprising: (a) an alkylated melamine that is essentially free from isocyanate reactive hydrogen such that the alkylated melamine is essentially unreactive to a polyisocyanate; and (b) a polyisocyanate having two or more free isocyanate crosslinking functional groups;
C) mixing said crosslinkable component with said crosslinking component to form a coating composition, wherein said coating composition is essentially free from acid catalyst;
D) applying said coating composition over said substrate to form a wet coating layer thereon; and
E) curing said wet coating layer at a temperature in a range of from about 80° C. to about 200° C. to form said coating layer.

2. The process of claim 1 , wherein the film forming polymer is selected from acrylic polymers, polyester polymers, polyurethane polymers, alkyd resins, or a combination thereof.

3. The process of claim 1 , wherein the alkylated melamine comprises an alkylation group selected from C1-C10 alkyls.

4. The process of claim 1 further comprising the steps of mixing a pigment, a solvent, an ultraviolet light stabilizer, an ultraviolet light absorber, an antioxidant, a hindered amine light stabilizer, a leveling agent, a rheological agent, a thickener, an antifoaming agent, a wetting agent, or a combination thereof, into said crosslinkable component or said coating composition.

5. The process of claim 1 , wherein said coating composition is at a pH in a range of from about 6.9 to about 8.1.

6. The process of claim 1 , wherein the weight ratio of melamine:polyisocyanate is in a range of from about 1:0.1 to about 1:10.

7. A coating composition comprising:
a) a crosslinkable component comprising a film forming polymers having a crosslinkable functional group, wherein the crosslinkable functional group is a hydroxyl group, and wherein the crosslinkable component comprises in a range of from about 20% to about 80% of water, percent based on the total weight of the crosslinkable component; and
b) a crosslinking component comprising: (a) an alkylated melamine that is essentially free from isocyanate reactive hydrogen such that the alkylated melamine is essentially unreactive to a polyisocyanate, and (b) a polyisocyanate having two or more free isocyanate crosslinking functional groups;
wherein the coating composition is essentially free from acid catalyst.

8. The coating composition of claim 7 , wherein the film forming polymer is selected from acrylic polymers, polyester polymers, polyurethane polymers, alkyd resins, or a combination thereof.

9. The coating composition of claim 7 , wherein the alkylated melamine comprises an alkylation group selected from C1-C10 alkyls.

10. The coating composition of claim 7 further comprising a pigment, a solvent, an ultraviolet light stabilizer, an ultraviolet light absorber, an antioxidant, a hindered amine light stabilizer, a leveling agent, a rheological agent, a thickener, an antifoaming agent, a wetting agent, or a combination thereof.

11. The coating composition of claim 7 , wherein the coating composition is at a pH in a range of from about 6.9 to about 8.1.

12. The coating composition of claim 7 , wherein the weight ratio of melamine:polyisocyanate is in a range of from about 1:0.1 to about 1:10.

Assignees

• Axalta Coating Systems Ip Co
• Azalta Coating Systems Ip Co Llc

Inventors

• Yokoyama Ayumu
• Saliya Rajesh Gopalan
• Houze Eric C
• Petkovska Violeta Ilieva

Classifications

• C08K5/0025

  Crosslinking or vulcanising agents; including accelerators · CPC title

• Y10T428/31551

  Of polyamidoester [polyurethane, polyisocyanate, polycarbamate, etc.] · CPC title

• C09D175/04 Primary

  Polyurethanes · CPC title

• C09D5/024

  characterised by the additives · CPC title

• C08G18/722

  Combination of two or more aliphatic and/or cycloaliphatic polyisocyanates · CPC title