Coating composition comprising a polyisocyanate and a polyol

Patent metadata

Field	Value
Publication number	US-10144795-B2
Application number	US-201715650256-A
Country	US
Kind code	B2
Filing date	Jul 14, 2017
Priority date	Oct 22, 2008
Publication date	Dec 4, 2018
Grant date	Dec 4, 2018

Abstract

The invention relates to a non-aqueous coating composition comprising
a. a polyisocyanate, b. a polyol having an average functionality of more than 3 hydroxyl groups per molecule, c. a metal based curing catalyst for the addition reaction of isocyanate groups and hydroxyl groups, and d. a mercapto carboxylic acid,

wherein the coating composition does not contain a carboxylic acid wherein the carbonyl group of the carboxylic acid is in conjugation with a π-electron system.

First claim

The invention claimed is:

1. A non-aqueous coating composition consisting essentially of,
a) an aliphatic or cycloaliphatic polyisocyanate,
b) a polyol having an average functionality of more than 3 hydroxyl groups per molecule, wherein the polyol is selected from polyester polyols, polyacrylate polyols, polycarbonate polyols, polyurethane polyols, melamine polyols, and mixtures thereof,
c) the reaction product of
i) a metal based curing catalyst for the addition reaction of isocyanate groups and hydroxyl groups, based on a metal selected from the group consisting of tin, bismuth, zirconium, and mixtures thereof and
ii) a mercapto carboxylic acid,
and

d) optionally, a volatile organic solvent,
wherein the coating composition does not contain a carboxylic acid wherein the carbonyl group of the carboxylic acid is in conjugation with a π-electron system.

2. The coating composition according to claim 1 , wherein the catalyst for the addition reaction of isocyanate groups and hydroxyl groups is based on tin.

3. The coating composition according to claim 1 , wherein the amount of metal based curing catalyst is in the range of 0.001 to 10 weight-%, calculated on the non-volatile matter of the composition.

4. The coating composition according to claim 1 , wherein the mercapto carboxylic acid is selected from the group consisting of 2-mercapto-carboxylic acids, 3-mercapto-carboxylic acids, and mixtures thereof.

5. The coating composition according to claim 1 , wherein the amount of mercapto carboxylic acid is in the range of 0.1 to 18 weight-%, calculated on the non-volatile matter of the composition.

6. The coating composition according to claim 1 , wherein component b) is a mixture of a polyester polyol and a polyacrylate polyol.

7. The coating composition according to claim 1 , wherein the composition comprises the volatile organic solvent.

8. The coating composition according to claim 6 , wherein the amount of volatile organic solvent does not exceed 420 g/l of coating composition.

9. A kit of parts for preparing a coating composition according to claim 1 , the kit of parts consisting essentially of
a) the polyol,
b) the polyisocyanate, and
(c) a metal based curing catalyst for the addition reaction of isocyanate groups and hydroxyl groups, based on a metal selected from the group consisting of tin, bismuth, zirconium, and mixtures thereof,
(d) a mercapto carboxylic acid; and
(e) optionally, a diluent module comprising a volatile organic solvent;
wherein the metal based catalyst for the addition reaction of isocyanate groups and hydroxyl groups and the mercapto carboxylic acid are distributed, individually or in combination, over one or more of the modules.

10. The kit of parts according to claim 9 ,
wherein the kit of parts comprises the diluent module comprising a volatile organic solvent.

11. A method for forming a coating layer, the method comprising applying the coating composition according to claim 1 to an automobile or a transportation vehicle.

12. The method according to claim 11 , wherein the formed coating layer is a layer in a multi-layer lacquer coating.

13. The method according to claim 11 , wherein the formed coating layer is a top coat layer in a multi-layer lacquer coating.

14. A process of coating a substrate comprising
i) applying the coating composition according to claim 1 to a substrate, and
ii) curing the coating composition at a temperature in the range of 40 to 80° C.

15. The process of coating a substrate according to claim 14 , wherein component b) is a mixture of a polyester polyol and a polyacrylate polyol and the amount of volatile organic solvent does not exceed 420 g/l of coating composition.

16. The kit of parts according to claim 10 wherein the metal based catalyst for the addition reaction of isocyanate groups and hydroxyl groups and the mercapto carboxylic acid are distributed, individually or in combination, only over one or more of modules a) and c).

Assignees

• Akzo Nobel Coatings Int Bv

Inventors

• Van Steenis Dirk Jan Vincent Christiaan
• Van Den Haak Hendrik Jan Willem
• Scherer Taco

Classifications

• C08G18/4288

  modified by higher fatty oils or their acids or by resin acids · CPC title

• C08G18/242

  organometallic compounds containing tin-carbon bonds · CPC title

• C08G18/246

  containing also tin-carbon bonds · CPC title

• C08G18/4063

  Mixtures of compounds of group C08G18/62 with other macromolecular compounds · CPC title

• C08G18/22

  containing metal compounds · CPC title