2K thermosetting powder coating compositions

Patent metadata

Field	Value
Publication number	US-11479679-B2
Application number	US-201515304354-A
Country	US
Kind code	B2
Filing date	Apr 8, 2015
Priority date	Apr 16, 2014
Publication date	Oct 25, 2022
Grant date	Oct 25, 2022

Abstract

A thermosetting powder coating composition C (PCC C) includes a physical mixture of a thermosetting powder coating composition A (PCC A) with a separate, distinct thermosetting powder coating composition B (PCC B). Also provided are processes for making the thermosetting powder coating composition C and for coating an article with the thermosetting powder coating composition C. A cured thermosetting powder coating composition C (c-PCC C) is also provided so as to obtain articles having coated and cured thereon the thermosetting powder coating composition C. Heat-curing can occur at low temperatures. The cured c-PCC C is a powder coating having at least one desirable property such as excellent resistance to swelling, good smoothness, good chemical resistance, low gloss, and/or low yellowness.

First claim

The invention claimed is:

1. A two component (2K) thermosetting powder coating composition C (PCC C) comprising a physical mixture of two different, separate and distinct thermosetting powder coating compositions A (PCC A) and B (PCC B), wherein the weight ratio R=weight PCC A/weight PCC B, is at least 0.01 and at most 99 and the total weight of the mixture of PCC A and PCC B in PCC C, is at least 10% w/w based on the total weight of PCC C, and wherein,
i) PCC A comprises:
A1: an unsaturated polyester resin comprising ethylenic unsaturations having a measured weight per ethylenic unsaturation (WPU) of at least 250 and at most 2200 g/mol;
A2: a copolymerizable agent comprising reactive unsaturations that are different from and are capable of reacting with the ethylenic unsaturations of the unsaturated resin A1, wherein the copolymerizable agent A2 is selected from the group consisting of:
a) a crystalline copolymerizable resin (CCR) having a WPU of at least 190 and at most 1500 g/mol and a M n equal to or higher than 350 Da, and
b) a mixture of a crystalline copolymerizable resin (CCR) with an amorphous copolymerizable resin (ACR) wherein each of the CCR and ACR has a WPU of at least 190 and at most 1500 g/mol and a M n equal to or higher than 350 Da and wherein the mixture has a weight ratio M of weight ACR/weight CCR of at most 1; wherein

the total weight of A1 and A2 in PCC A, is at least 10% w/w based on the total weight of PCC A;
A3: an unsaturated monomer, in an amount of 0-0.9% w/w based on the total weight of PCC A;
A4: a thermal radical initiator in an amount of at least 1 and at most 500 mmol thermally labile groups/Kg of total weight of A1 and A2, said thermal radical initiator comprising:
A4-1: a peroxide selected from the group consisting of peresters, monopercarbonates and mixtures thereof, said peroxide is present in an amount of at least 1 and at most 245 mmol peroxy groups/Kg of total weight of A1 and A2;
A5: a transition metal substance in an amount of 0-4.5 mmol metal/Kg of total weight of A1 and A2, said transition metal substance is selected from the group consisting of Co, Mn, Cu, Fe, V, Ti, transition metal compounds of Co, transition metal compounds of Mn, transition metal compounds of Cu, transition metal compounds of Fe, transition metal compounds of V, transition metal compounds of Ti and mixtures thereof;
A6: an inhibitor in an amount of at least 13 and at most 5000 mg inhibitor/Kg of total weight of A1 and A2; and wherein

ii) PCC B comprises:
B1: an unsaturated polyester resin comprising ethylenic unsaturations having a WPU of at least 250 and at most 2200 g/mol;
B2: copolymerizable agent comprising reactive unsaturations that are different from and are capable of reacting with the ethylenic unsaturations of the unsaturated resin B1, wherein the copolymerizable agent B2 is selected from the group consisting of:
a) a crystalline copolymerizable resin (CCR) having a WPU of at least 190 and at most 1500 g/mol and a M n equal to or higher than 350 Da, and
b) a mixture of a crystalline copolymerizable resin (CCR) with an amorphous copolymerizable resin (ACR) wherein each of the CCR and ACR has a WPU of at least 190 and at most 1500 g/mol and a M n equal to or higher than 350 Da and wherein the mixture has a weight ratio M of weight ACR/weight CCR of at most 1; wherein

the total weight of B1 and B2 in PCC B, is at least 10% w/w based on the total weight of PCC B;
B3: an unsaturated monomer, in an amount of 0-0.9% w/w based on the total weight of PCC B;
B4: a thermal radical initiator in an amount of at least 1 and at most 500 mmol thermally labile groups/Kg of total weight of B1 and B2, said thermal radical initiator comprising:
B4-1: a peranhydride in an amount of at least 0.5 and at most 300 mmol peroxy groups/Kg of total weight of B1 and B2;
B5: a transition metal substance in an amount of at least 0.5 and at most 50 mmol metal/Kg of total weight of B1 and B2, said transition metal substance is selected from the group consisting of Co, Mn, Cu, Fe, V, Ti, transition metal compounds of Co, transition metal compounds of Mn, transition metal compounds of Cu, transition metal compounds of Fe, transition metal compounds of V, transition metal compounds of Ti and mixtures thereof;
B6: an inhibitor in an amount of at least 16 and at most 5000 mg inhibitor/Kg of total weight of B1 and B2; and wherein

iii) the total amount of unsaturated monomer in PCC C ranges from 0 up to 0.9% w/w based on the total weight of PCC C; and wherein
iv) the total amount of thermal radical initiator in PCC C is at least 22 and at most 500 mmol thermally labile groups/kg of total weight of unsaturated resins and copolymerizable agent in PCC C; and wherein the thermally labile groups are selected from peroxy and azo groups, and wherein
(v) a cured powder coating derived from PCC C on medium density fiberboard has a gloss at 60° equal to or lower than 45 as measured according to ASTM-D-523/70.

2. The PCC C according to claim 1 , wherein PCC A further comprises:
A7: a thiol in an amount of 0-5 mmol thiol groups/Kg of total weight of A1 and A2; and/or
A8: an acetoacetamide compound in an amount of 0-200 mmol acetoacetamide compound/Kg of total weight of A1 and A2; and/or
A9: a 1,2,3 trihydroxy aryl compound in an amount of 0-10 mmol 1,2,3 trihydroxy aryl compound/Kg of total weight of A1 and A2, if the A5 comprises one or both of Cu and a transition metal compound of Cu.

3. The PCC C according to claim 1 wherein PCC A further comprises:
A10: a free amine in an amount such that a ratio L of mmol thermally labile groups/mmol free amine is at least 1.1, wherein the mmol thermally labile groups and the mmol free amine each refers to 1 Kg of total weight of A1 and A2.

4. The PCC C according to claim 1 , wherein PCC B further comprises:
B7: a thiol in an amount of 0-5 mmol thiol groups/Kg of total weight of B1 and B2; and/or
B8: an acetoacetamide compound in an amount of 0-5 mmol acetoacetamide compound/Kg of total weight of B1 and B2; and/or
B9: a 1,2,3 trihydroxy aryl compound in an amount of 0-5 mmol 1,2,3 trihydroxy aryl compound/Kg of total weight of B1 and B2, if B5 comprises one or both of Cu and a transition metal compound of Cu.

5. The PCC C according to claim 1 , wherein PCC B further comprises:
B10: a free amine in an amount such that a ratio L of mmol thermally labile groups/mmol free amine is at least 1.1, wherein the mmol thermally labile groups and the mmol free amine each refers to 1 Kg of total weight of B1 and B2.

6. The PCC C according to claim 1 , wherein B4 further comprises:
B4-2 a: a hydroperoxide in an amount of 0-5 mmol h-peroxy groups/Kg of total weight of B1 and B2; and/or
B4-2 b: a perester in an amount 0-25 mmol p-peroxy groups/Kg of total weight of B1 and B2; and/or
B4-2 c: an alkylperoxy carbonate in an amount of 0-25 mmol ac-peroxy groups/Kg of total weight of B1 and B2.

7. The PCC C according to claim 1 , wherein
vi) the total amount of transition metal substance in PCC C is at least 0.25 and at most 50 mmol metal/Kg of total weight of unsaturated resins and copolymerizable agent in PCC C;
vii) the total amount of inhibitor in PCC C is at least 13 and at most 5000 mg inhibitor/Kg of total weight of unsaturated resins and copolymerizable agent in PCC C.

8. The PCC C according to claim 1 , wherein R is at least 0.1 and at most 9.

9. The PCC C according to claim 1 , wherein R is at least 0.2 and at most 4.

10. The PCC C according to claim 1 , wherein a molar ratio K A of mol of the reactive unsaturations in A2/mol of the ethylenic unsaturations in A1 is at least 0.90 and at most 1.10.

11. The PCC C according to claim 1 , whe

Assignees

• Covestro Netherlands Bv

Inventors

• Bongaerts Johannes Gertrudis Christianus
• Wellenberg Petrus Henricus Marinus
• Jansen Johan Franz Gradus Antonius

Classifications

• C08K3/10

  Metal compounds · CPC title

• C08K3/11

  Compounds containing metals of Groups 4 to 10 or of Groups 14 to 16 of the Periodic Table · CPC title

• C08K5/14

  Peroxides · CPC title

• C08K5/0025

  Crosslinking or vulcanising agents; including accelerators · CPC title

• C09D15/00

  Woodstains · CPC title