Coating powder formulation
The present invention relates to a powder coating formulation, comprising at least one partially crystalline thermoplastic unsaturated polyester (A), at least one thermoplastic allyl prepolymer (B) which is copolymerizable with said polyester, and a thermal initiation system (C), including at least one thermal initiator, wherein the allyl prepolymer (B) has a weight average molar mass greater than 5000 g/mol, preferably greater than 10000 g/mol, and particularly preferably greater than 20000 g/mol, and/or has a viscosity of 30 mPas to 200 mPas, preferably of between 40 mPas and 170 mPas, particularly preferably of between 50 mPas and 150 mPas, and wherein the unsaturated polyester (A) has a melting point of between 90 and 120° C., preferably of 90-110° C., particularly preferably of 90-105° C., and still more preferably of 90-100° C.
1. A powder coating formulation, comprising at least one partially crystalline thermoplastic unsaturated polyester (A), at least one thermoplastic allyl prepolymer (B), which is copolymerizable with said polyester, and a thermal initiation system (C), including at least one thermal initiator, wherein the allyl prepolymer (B) has a weight average molar mass greater than 5000 g/mol, and/or has a viscosity of 30 mPas to 200 mPas, and wherein the unsaturated polyester (A) has a melting point of between 90 and 120° C.
2. The powder coating formulation of claim 1 , wherein the allyl prepolymer (B) has a weight average molar mass greater than 20000 g/mol, and/or has a viscosity of 50 mPas and 150 mPas, and wherein the unsaturated polyester (A) has a melting point of between 90 and 100° C.
3. The powder coating formulation of claim 1 , wherein the allyl prepolymer (B) is a polymer of ortho- or meta-phthalic acid diallyl ester.
4. The powder coating formulation of claim 1 , wherein the allyl prepolymer (B) is a polyester comprising allyl groups.
5. The powder coating formulation of claim 1 , wherein the unsaturated polyester (A) has a double bond equivalent weight of 140 to 1000 g/mol.
6. The powder coating formulation of claim 5 , wherein the unsaturated polyester (A) has a double bond equivalent weight of 400 to 500 g/mol.
7. The powder coating formulation of claim 1 , wherein the allyl prepolymer (B) has a double bond equivalent weight of 250 to 2000 g/mol.
8. The powder coating formulation of claim 7 , wherein the allyl prepolymer (B) has a double bond equivalent weight of 300 to 400 g/mol.
9. The powder coating formulation of claim 1 , wherein the thermal initiation system (C) comprises at least one thermal initiator, which is characterized by having a temperature, at which its half-life is one minute, of between 80 and 150° C.
10. The powder coating formulation of claim 9 , wherein the thermal initiation system (C) comprises at least one thermal initiator, which is characterized by having a temperature, at which its half-life is one minute, of between 100 and 130° C.
11. The powder coating formulation of claim 1 , wherein the thermal initiation system (C) comprises a peroxide.
12. The powder coating formulation of claim 11 , wherein the peroxide is a dialkyl peroxide, a diacyl peroxide, or a perester.
13. The powder coating formulation of claim 1 , wherein the proportion of the partially crystalline thermoplastic unsaturated polyester (A) is between 20-80%, based on the binding agent.
14. The powder coating formulation of claim 13 , wherein the proportion of the partially crystalline thermoplastic unsaturated polyester (A) is between 40-75%, based on the binding agent.
15. The powder coating formulation of claim 1 , wherein the proportion of the allyl prepolymer (B) is between 20-80%, based on the binding agent.
16. The powder coating formulation of claim 15 , wherein the proportion of the allyl prepolymer (B) is between 20-60%, based on the binding agent.