One component heat-curable powder coating composition

Patent metadata

Field	Value
Publication number	US-10328455-B2
Application number	US-201514858187-A
Country	US
Kind code	B2
Filing date	Sep 18, 2015
Priority date	Nov 7, 2008
Publication date	Jun 25, 2019
Grant date	Jun 25, 2019

Abstract

The invention relates to a one component heat-curable powder coating composition comprising a resin containing reactive unsaturations and wherein all said reactive unsaturations are carbon carbon double bonds connected directly to an electron withdrawing group, a thermal initiation system comprising a transition metal catalyst and a peroxide, wherein the peroxide is chosen from the group of peroxyesters, mono-peroxycarbonates and mixtures thereof and a co-crosslinker chosen from the group of vinylethers, vinylesters, vinylamides, itaconates, enamines and mixtures thereof.

First claim

The invention claimed is:

1. A one component heat curable powder coating composition comprising:
(i) a polyester resin containing reactive unsaturations, the polyester resin having a weight per the reactive unsaturations (WPU) as determined using 1H-NMR which is higher than 250 and lower than 1500 g/mole,
(ii) a thermal initiation system comprising (a) a transition metal catalyst and (b) a peroxide, wherein
(a) the transition metal catalyst is selected from the group consisting of transition metal salts, transition metal complexes and mixtures thereof, wherein the transition metal is Mn, Fe, Co or Cu, and wherein
(b) the peroxide is selected from the group consisting of peroxyesters, monoperoxycarbonates and mixtures thereof, and wherein the peroxide is represented by formula (1):

wherein
R 1 , R 2 and R 3 each independently stand for an alkyl, and wherein X stands for R 4 or for OR 4 , wherein R 4 stands for an alkyl, an aryl or for an oligomer or polymer, and wherein
the amount of peroxide is at least 10 mmol peroxide/Kg resin containing reactive unsaturations and co-crosslinker, and

(iii) a co-crosslinker having a weight per unsaturation (WPU) as determined using 1H-NMR higher than 150 and lower than 870 g/mole, said crosslinker being chosen from the group consisting of vinylethers, vinyletherurethanes, vinylesters, vinylamides, itaconates, enamines and mixtures thereof, wherein
all of the reactive unsaturations of the polyester resin are carbon-carbon double bonds connected directly to an electron withdrawing group and are reactive towards radicals generated by the peroxide, and wherein
the thermal initiation system is present in an amount such that when the powder coating composition is applied to a substrate and cured at a temperature of 130° C. for 20 minutes, the resulting coating resists at least 70 acetone double rubs (ADR), wherein each ADR is a back and forward movement over a surface of the coating having a thickness of approximately 60 μm using a cotton cloth drenched in acetone covering a hammer head having a weight of 980 grams and a contact surface area with the coating of 2 cm 2 .

2. The composition according to claim 1 , wherein the resin has a WPU higher than 250 and less than 1150 g/mole.

3. The composition according to claim 1 , wherein the resin has a WPU higher than 500 and less than 1500 g/mole.

4. The composition according to claim 1 , wherein the resin has a WPU higher than 500 and less than 1150 g/mole.

5. The composition according to claim 1 , wherein the co-crosslinker has a WPU higher than 150 and lower than 650 g/mole.

6. The composition according to claim 1 , wherein the co-crosslinker has a WPU higher than 150 and lower than 630 g/mole.

7. The composition according to claim 1 , wherein the resin has a hydroxyl value in the range of from 0 to 70 mg KOH per g resin.

8. The composition according to claim 1 , wherein the reactive unsaturations of the resin are based on maleic acid, fumaric acid, itaconic acid, acrylic acid and/or methacrylic acid.

9. The composition according to claim 1 , wherein the reactive unsaturations of the resin are based on maleic acid, fumaric acid, citraconic acid, itaconic acid, and/or mesaconic acid.

10. The composition according to claim 1 , wherein the reactive unsaturations of the resin are based on fumaric acid and/or maleic acid.

11. The composition according to claim 1 , wherein the reactive unsaturations of the resin are based on fumaric acid.

12. The composition according to claim 1 , wherein the peroxide is t-butyl peroxybenzoate, t-butyl peroxy-2-ethyl hexanoate, t-amyl peroxy (2-ethyl) hexanoate or t-butyl peroxy-2-ethylhexyl carbonate.

13. The composition according to claim 1 , wherein the transition metal is a Mn, Fe, or Cu salt or complex.

14. The composition according to claim 1 , wherein the co-crosslinker is chosen from the group of vinylethers, vinylesters and mixtures thereof.

15. The composition according to claim 1 , wherein the co-crosslinker is a vinylether.

16. The composition according to claim 14 , wherein the resin has an acid value of less than 10 mg KOH per g resin.

17. The composition according to claim 15 , wherein the resin has an acid value of less than 10 mg KOH per g resin.

18. The composition according to claim 14 , wherein the resin has an acid value of less than 5 mg KOH per g resin.

19. The composition according to claim 15 , wherein the resin has an acid value of less than 5 mg KOH per g resin.

20. The composition according to claim 1 , wherein the composition further comprises an inhibitor.

21. The composition according to claim 20 , wherein the inhibitor is a hydroquinone or a catechol.

22. The composition according to claim 1 , wherein the resin has a glass transition temperature of at least 40° C. as measured via DSC at a heating rate of 5° C./min.

23. The composition according to claim 1 , wherein the resin has a glass transition temperature of at least 45° C. as measured via DSC at a heating rate of 5° C./min.

24. The composition according to claim 1 , wherein the resin has a glass transition temperature of at least 40 and of at most 65° C. as measured via DSC at a heating rate of 5° C./min.

25. The composition according to claim 1 , wherein the resin has a number average molecular weight in the range of from 1500 to 8000 Da.

26. The composition according to claim 1 , wherein the resin has a number average molecular weight in the range of from 2100 to 4000 Da.

27. The composition according to claim 1 , wherein
the reactive unsaturations of the resin are based on maleic acid, fumaric acid, itaconic acid, acrylic acid and/or methacrylic acid, said resin has a hydroxyl value in the range of from 0 to 70 mg KOH per g resin and a number average molecular weight in the range of from 1500 to 8000 Da and a glass transition temperature of at least 40° C. as measured via DSC at a heating rate of 5° C./min; and
the co-crosslinker has a WPU higher than 150 and lower than 630 g/mole and said co-crosslinker is chosen from the group of vinylethers, vinylesters and mixtures thereof.

28. The composition according to claim 27 , wherein the reactive unsaturations of the resin are based on fumaric acid and/or maleic acid.

29. The composition according to claim 1 , wherein
the reactive unsaturations of the resin are based on maleic acid, fumaric acid, itaconic acid, acrylic acid and/or methacrylic acid, said resin has a hydroxyl value in the range of from 0 to 70 mg KOH per g resin and a number average molecular weight in the range of from 1500 to 8000 Da and a glass transition temperature of at least 40° C. as measured via DSC at a heating rate of 5° C./min; and
the co-crosslinker has a WPU higher than 150 and lower than 630 g/mole and said co-crosslinker is chosen from the group of vinylethers, vinylesters and mixtures thereof; and
the composition comprises an inhibitor.

30. The composition according to claim 29 , wherein the reactive unsaturations of the resin are based on fumaric acid and/or maleic acid.

31. The composition according to claim 1 , wherein
the reactive unsaturations of the resin are based on maleic acid, fumaric acid, ita

Assignees

• Dsm Ip Assets Bv

Inventors

• Jansen Johan F G A
• Drijfhout Jan Pieter

Classifications

• C09D5/033 Primary

  characterised by the additives · CPC title

• C09D167/06

  Unsaturated polyesters having carbon-to-carbon unsaturation · CPC title

• C08K5/0025

  Crosslinking or vulcanising agents; including accelerators · CPC title

• C09D151/08

  grafted on to macromolecular compounds obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds · CPC title

• C08F283/01

  on to unsaturated polyesters {(C08F283/004 takes precedence)} · CPC title