Methods and compositions for coating substrates

Patent metadata

Field	Value
Publication number	US-9938425-B2
Application number	US-201414479499-A
Country	US
Kind code	B2
Filing date	Sep 8, 2014
Priority date	Feb 28, 2013
Publication date	Apr 10, 2018
Grant date	Apr 10, 2018

Abstract

A method for applying a multilayer coating comprising a basecoat and a clearcoat is disclosed. The basecoat is a curable aqueous composition comprising (1) polymeric particles prepared from ethylenically unsaturated compounds including a multi-ethylenically unsaturated monomer and a keto or aldo-functional monomer, and (2) a polyhydrazide. A hydrophobic polymer is present in the aqueous composition to improve its humidity resistance.

First claim

What is claimed is:

1. An aqueous thermosetting coating composition comprising:
(i) a continuous phase comprising water, and
(ii) a dispersed phase comprising:
(A) polymeric particles prepared from the polymerization of a mixture of ethylenically unsaturated compounds including ethylenically unsaturated monomers comprising from:
(1) 2 to 30 percent by weight of a multi-ethylenically unsaturated monomer and
(2) at least 30 percent by weight of an aldo or keto group-containing ethylenically unsaturated monomer, the percentages by weight being based on total weight of the ethylenically unsaturated monomers;

(B) a polymer prepared from polymerizing the following mixture of ethylenically unsaturated monomers:

(I) a C 8 to C 20 alkyl ester of (meth)acrylic acid;
(II) a polymerizable ethylenically unsaturated monomer comprising a polar functional group; and
(III) optionally, a polymerizable ethylenically unsaturated monomer, wherein (I), (II) and (III) are different from each other; and
wherein the polymer has a glass transition temperature of −10° C. or less;
(C) a polyhydrazide; and
(D) one or more pigments.

2. The composition of claim 1 in which the mixture of ethylenically unsaturated compounds includes an ethylenically unsaturated polyurethane.

3. The composition of claim 2 in which the ethylenically unsaturated polyurethane is prepared from reacting an organic polyisocyanate with a polyol containing carboxylic acid functionality and a hydroxyalkyl (meth)acrylate such that the ethylenically unsaturated polyurethane is free of isocyanate groups.

4. The composition of claim 3 in which the ethylenically unsaturated polyurethane comprises from 30 to 60 percent by weight of the mixture of ethylenically unsaturated compounds and the ethylenically unsaturated monomers in (A) comprise from 40 to 70 percent by weight of the mixture of ethylenically unsaturated compounds; the percentages by weight being based on total weight of the ethylenically unsaturated compounds.

5. The composition of claim 1 in which the ethylenically unsaturated monomers in (A) comprise from 4 to 30 percent by weight of an alkyl ester of (meth)acrylic acid having at least 6 carbon atoms in the alkyl group; the percentages by weight being based on total weight of the ethylenically unsaturated monomers.

6. The composition of claim 1 in which the polyhydrazide is a bishydrazide of a dicarboxylic acid containing from 2 to 16 carbon atoms.

7. The composition of claim 1 in which a film of the polymeric particles has a T g less than 25° C.

8. The composition of claim 1 in which the mixture of ethylenically unsaturated compounds contains at least one compound containing carboxylic acid groups that are at least partially neutralized with an amine.

9. The composition of claim 8 in which the amine is a volatile amine.

10. The composition of claim 1 which additionally contains (E) a polycarbodiimide.

11. The composition of claim 1 wherein the C 8 to C 20 alkyl ester of (meth)acrylic acid (I) comprises octyl (meth)acrylate, lauryl (meth)acrylate, cetyl (meth)acrylate, stearyl (meth)acrylate, behenyl (meth)acrylate, and/or eicosyl (meth)acrylate.

12. The composition of claim 11 wherein the C 8 to C 20 alkyl ester of (meth)acrylic acid (I) is present at an amount of at least 50 weight percent and not more than 95 weight percent based on total weight of monomer solids present in polymer (B).

13. The composition of claim 11 wherein the C 8 to C 20 alkyl ester of (meth)acrylic acid (I) comprises lauryl (meth)acrylate.

14. The composition of claim 1 wherein the polar functional group of the ethylenically unsaturated monomer (II) comprises carboxyl groups, hydroxyl groups, and/or amine groups.

15. The composition of claim 14 wherein the polar functional group of the ethylenically unsaturated monomer (II) comprises a carboxyl group.

16. The composition of claim 1 wherein the ethylenically unsaturated monomer (II) comprises (meth)acrylic acid.

17. The composition of claim 1 wherein the ethylenically unsaturated monomer (II) is present at an amount of at least 0.1 weight percent and not more than 5 weight percent based on total weight of monomer solids present in polymer (B).

18. The composition of claim 1 wherein the polymer (B) has a glass transition temperature of −30° C. or less.

19. The composition of claim 1 wherein the polymer (B) is present in the dispersed phase at an amount of at least 2 weight percent and not more than 30 weight percent resin solids based on the total weight of resin solids of the dispersed phase.

Assignees

• Ppg Ind Ohio Inc

Inventors

• Swarup Shanti
• Sadvary Richard J

Classifications

• C08G18/4854

  Polyethers containing oxyalkylene groups having four carbon atoms in the alkylene group · CPC title

• C08G18/672

  Esters of acrylic or alkyl acrylic acid having only one group containing active hydrogen · CPC title

• B05D7/577 Primary

  some layers being coated "wet-on-wet", the others not · CPC title

• C08F290/067

  Polyurethanes; Polyureas · CPC title

• C08G18/348

  Hydroxycarboxylic acids · CPC title