Powder composition

Patent metadata

Field	Value
Publication number	US-10604661-B2
Application number	US-201615374017-A
Country	US
Kind code	B2
Filing date	Dec 9, 2016
Priority date	Jan 31, 2008
Publication date	Mar 31, 2020
Grant date	Mar 31, 2020

Abstract

There is described a powder coating composition suitable for food contact use comprising a mix of: (A) a first polyester that is amorphous and COOH functional being obtained from IPA and/or TPA and no more than 10 mole % neopentyl glycol (NPG); (B) a second optional COOH functional polyester obtained from analiphatic diacid and analiphatic diol, and (C) a curing agent that comprises functional groups reactable with the COOH of the polyester(s). The powders are suitable for coating the interior of metal cans especially those holding alcoholic beverages.

First claim

The invention claimed is:

1. A powder coating composition comprising a binder and 0 mole % of neopentyl glycol, wherein the binder consists of a mixture of:
(A) a first polyester that is amorphous and comprises at least one carboxy group; the first polyester having an acid number from 15 to 100 mg KOH/g, a glass transition temperature (Tg) from 45° C. to 80° C. and a viscosity from 5 to 15000 mPa·s, said first polyester being obtained from:
an acid component comprising:
(a) a dicarboxylic acid component consisting of isophthalic acid, terephthalic acid and mixtures thereof; and
(c) from 1 up to 18 mole % of polyacids comprising at least three carboxy groups; and
a polyol component (b) consisting of propylene glycol;
(b) a polyol component consisting of propylene glycol; and
(B) optionally a second polyester that is amorphous and that comprises at least one carboxy group; the second polyester being obtained from an aliphatic diacid and an aliphatic diol, and
(C) a curing agent that comprises functional groups reactable with carboxylic acid groups on the polyester(s) (A) and (B), which is at least one selected from the group consisting of an epoxy resin and a β-hydroxyalkylamide hardener, wherein the binder consists essentially of amorphous polyesters.

2. The composition according to claim 1 , in which the first polyester (A) has an acid number from 20 to 80 mg KOH/g.

3. The composition according to claim 1 , wherein the binder consists of a mixture of said first polyester (A), said second polyester (B) and said curing agent (C).

4. The composition according to claim 1 , in which the dicarboxylic acid component (a) is terephthalic acid, optionally in combination with isophthalic acid.

5. The composition according to claim 1 , in which the dicarboxylic acid component (a) is isophthalic acid.

6. The composition according to claim 1 , in which
the second polyester (B) is obtained from:
(a) a dicarboxylic acid component comprising, by mole % of total acid,
(i) from 75 to 100 mole % of a first acid comprising at least one linear non-branched aliphatic diacid selected from the group consisting of:
succinic acid, adipic acid, glutaric acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, 1,12-dodecanedioic acid, 1,4-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid anhydrides thereof, and any mixtures thereof; and
(ii) optionally from 0 to 25 mole % of a second acid selected from the group consisting of fumaric acid, maleic anhydride, phthalic anhydride, isophthalic acid, terephthalic acid, and any mixtures thereof; and

(b) a polyol component comprising:
an alcohol selected from the group consisting of:
propyleneglycol, 2-methyl-1,3-propanediol, 2-butyl-2-ethyl-1,3-propanediol, 1-ethyl-2-methyl-1,3-propanediol, 2-ethyl-2-methyl-1,3-propanediol, diethyleneglycol; 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, hydrogenated Bisphenol A; ethyleneglycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,14-tetradecanediol, 1,16-hexadecanediol, hydroxypivalate of neopentyl glycol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, hydrogenated Bisphenol A, and any mixtures thereof.

7. The composition according to claim 1 , in which the first and/or second polyester is branched.

8. The composition according to claim 1 , wherein the powder coating composition is a thermosetting powder coating composition comprising a binder system consisting of from 19 to 99 parts by weight of polyester (A), from 0 to 44.5 parts by weight of polyester (B), and from 1 to 65 parts by weight of the curing agent (C),
wherein polyester (B) has a Tg of less than or equal to 50° C. and which comprises with respect to a total amount of acids, from 75 to 100 mol % of an aliphatic diacid and, with respect to a total amount of alcohols, from 75 to 100 mol % of an aliphatic diol different from neopentyl glycol.

9. The composition according to claim 1 , wherein the binder consists of:
(A) from 19.0 to 99.0 parts by weight of the first polyester;
(B) from 44.5 to 0 parts by weight of the second polyester; and
(C) from 1 to 65 parts by weight of the curing agent,
all parts being based on a total weight of polyester resins and curing agents.

10. The composition according to claim 1 , wherein the binder consists of:
(A) from 24.5 to 95.5 parts by weight of the first polyester;
(B) from 30.0 to 1.5 parts by weight of the second polyester; and
(C) from 3 to 50 parts by weight of the curing agent,
all parts being based on a total weight of polyester resins and curing agents.

11. The composition according to claim 1 , wherein the polyacids (c) comprising at least three carboxy groups are selected from the group consisting of trimellitic acid, pyromellitic acid and their corresponding anhydrides.

12. The composition according to claim 1 , wherein the binder consists of a mixture of the first polyester (A) and the curing agent (C).

13. A coated article obtained by a process comprising the steps of
coating at least one surface of a substrate with the powder coating composition according to claim 1 ; and
heating the coated substrate to thermally cure the coating thereon to form an adherent layer of the coating composition on the substrate.

14. The article according to claim 13 , wherein the substrate is a metal can holding an alcoholic beverage.

15. The article according to claim 13 , wherein the substrate is selected from metal sheets for food and/or beverage products.

16. The article according to claim 13 , wherein the substrate is selected from metal containers for food and/or for beverage products.

17. The article according to claim 13 , wherein an interior and/or exterior surface of the substrate are coated, and
wherein the substrate is a food container coming into contact with alcohol.

18. The article according to claim 13 , wherein at least an interior surface of the substrate is coated, and
wherein the substrate is a metal can for holding an alcoholic beverage.

19. A process for coating substrates comprising the steps of
coating at least one surface of a substrate with a powder coating composition according to claim 1 ; and
heating the coated substrate to thermally cure the coating thereon to form an adherent layer of the coating composition on the substrate.

20. The process according to claim 19 wherein the substrate is selected from metal sheets for food and/or beverage products.

21. The process according to claim 19 wherein the substrate is selected from metal containers for food and/or for beverage products.

22. The process according to claim 19 , wherein the interior and/or exterior of a food container coming into contact with alcohol is coated.

23. A powder coating composition comprising a binder and 0 mole % of neopentyl glycol, wherein the binder consists of a mixture of:
(A) a first polyester that is amorphous and comprises at least one carboxy group; the first polyester having an acid number from 15 to 100 mg KOH/g, a glass transition temperature (Tg) from 45° C. to 80° C. and a viscosity from 5 to 15000 mPa.s, said first polyester being obtained from an acid component and a polyol component wherein:
the acid component consists of:
(a) a dicarboxylic acid component consisting of isophthalic acid, terephthalic acid and mixtures thereof; and
(b) from 1 up to 18 mole% of polyacids comprising at least three carb

Assignees

• ALLNEX Belgium SA

Inventors

• Moens Luc

Classifications

• Y10T428/1355

  Elemental metal containing [e.g., substrate, foil, film, coating, etc.] · CPC title

• C08K5/20

  Carboxylic acid amides · CPC title

• B65D25/14

  Linings or internal coatings (of containers made by folding or erecting blanks made of paper B65D5/56 {; linings for domestic water storage heaters F24H1/183}) · CPC title

• C08L2205/02

  containing two or more polymers of the same C08L -group · CPC title

• C08L67/02

  Polyesters derived from dicarboxylic acids and dihydroxy compounds (C08L67/06 takes precedence) · CPC title