Heat-curing powder-lacquer compositions yielding a matte surface after curing of the coating, as well as a simple method for production of same
The invention relates to heat-curing powder-lacquer compositions exhibiting a matte surface after curing of the coating, as well as to a simple method for production of the same.
1. A powder-lacquer composition, comprising:
A) at least one carboxylate-group-containing polymer having an acid number of 5 to 250 mg KOH/g and a glass transition temperature T g higher than 40° C.,
B) at least one β-hydroxyalkylamide having two or three or four β-hydroxyalkylamide groups per molecule and having one of the following formulas:
where
R 2 : methyl,
or
where R 1A denotes hydrogen and R 1B denotes methyl, ethyl, propyl,
or
where R 1A denotes methyl, ethyl, propyl and R 1B denotes hydrogen; and
A: 1,4-disubstituted cyclohexane ring of the formula
wherein the trans content of A is ≧70 mol %;
and wherein the β-hydroxyalkylamides exist in solid form below 150° C.; and
C) optionally, at least one processing aid and/or additive;
wherein the ratio of β-hydroxyalkylamide groups to the carboxylate groups ranges between 0.5:1 and 1.5:1.
2. The powder-lacquer composition according to claim 1 , wherein the trans content of A is ≧80 mol %.
3. The powder-lacquer composition according to claim 1 , wherein the trans content of A is ≧85 mol %.
4. The powder-lacquer composition according to claim 1 , wherein the O-hydroxyalkylamide is obtained from a dialkyl-1,4-cyclohexyldicarboxylate.
5. The powder-lacquer composition according to claim 4 , wherein the trans content of A is ≧80 mol %.
6. The powder-lacquer composition according to claim 4 , wherein the trans content of A is ≧85 mol %.
7. A powder-lacquer composition, comprising:
A) at least one carboxylate-group-containing polymer having an acid number of 5 to 250 mg KOH/g and a glass transition temperature T g higher than 40° C.,
B) a β-hydroxyalkylamide having the formula XII:
with a trans content on the cyclohexyl ring of greater than or equal to 70 mol %; and
C) optionally, at least one processing aid and/or additive;
wherein the ratio of β-hydroxyalkylamide groups to the carboxylate groups ranges between 0.5:1 and 1.5:1.
8. The powder-lacquer composition according to claim 7 , wherein the trans content on the cyclohexyl ring is ≧80 mol %.
9. The powder-lacquer composition according to claim 7 , wherein the trans content on the cyclohexyl ring is ≧85 mol %.
10. The powder-lacquer composition according to claim 1 , wherein the β-hydroxyalkylamide exists in solid form below 170° C.
11. The powder-lacquer composition according to claim 1 , wherein the β-hydroxyalkylamide exists in solid form below 180° C.
12. The powder-lacquer composition according to claim 7 , wherein the at least one carboxylate-group-containing polymer A) is a polyester having a glass transition temperature T g ranging from 40 to 80° C.; an acid number varying from 10 to 150 mg KOH/g; an OH number smaller than 15 mg KOH/g; and an average molecular weight M w of 1,000 to 10,000 g/mol.
13. The powder-lacquer composition according to claim 12 , wherein the at least one carboxylate-group-containing polymer A) has a glass transition temperature T g ranging from 40 to 70° C.; an acid number varying from 12 to 120 mg KOH/g; and an average molecular weight M w of 1,500 to 9,000 g/mol.
14. The powder-lacquer composition according to claim 13 , wherein the at least one carboxylate-group-containing polymer A) has an average molecular weight M w of 2,000 to 8,000 g/mol.
15. The powder-lacquer composition according to claim 7 , wherein the at least one carboxylate-group-containing polymer A) is an acrylic polymer having an OH number smaller than 10 mg KOH/g; an acid number of 10 to 350 mg KOH/g; a T g of 40 to 110° C.; and an M w of 500 to 50,000 g/mol.
16. The powder-lacquer composition according to claim 15 , wherein the at least one carboxylate-group-containing polymer A) is an acrylic polymer having an acid number of 20 to 300 mg KOH/g; a T g of 45 to 100° C.; and an M w of 1,000 to 30,000.
17. The powder-lacquer composition according to claim 16 , wherein the at least one carboxylate-group-containing polymer A) is an acrylic polymer having an acid number of 30 to 250 mg KOH/g; and an M w of 1,500 to 20,000 g/mol.
18. The powder-lacquer composition according to claim 1 , wherein the at least one carboxylate-group-containing polymer A) is a polyester having a glass transition temperature T g ranging from 40 to 80° C.; an acid number varying from 10 to 150 mg KOH/g; an OH number smaller than 15 mg KOH/g; and an average molecular weight M w of 1,000 to 10,000 g/mol.
19. The powder-lacquer composition according to claim 18 , wherein the at least one carboxylate-group-containing polymer A) has a glass transition temperature T g ranging from 40 to 70° C.; an acid number varying from 12 to 120 mg KOH/g; and an average molecular weight M w of 1,500 to 9,000 g/mol.
20. The powder-lacquer composition according to claim 19 , wherein the at least one carboxylate-group-containing polymer A) has an average molecular weight M w of 2,000 to 8,000 g/mol.
21. The powder-lacquer composition according to claim 1 , wherein the at least one carboxylate-group-containing polymer A) is an acrylic polymer having an OH number smaller than 10 mg KOH/g; an acid number of 10 to 350 mg KOH/g; a T g of 40 to 110° C.; and an M w of 500 to 50,000 g/mol.
22. The powder-lacquer composition according to claim 21 , wherein the at least one carboxylate-group-containing polymer A) is an acrylic polymer having an acid number of 20 to 300 mg KOH/g; a T g of 45 to 100° C.; and an M w of 1,000 to 30,000.
23. The powder-lacquer composition according to claim 22 , wherein the at least one carboxylate-group-containing polymer A) is an acrylic polymer having an acid number of 30 to 250 mg KOH/g; and an M w of 1,500 to 20,000 g/mol.
24. The powder-lacquer composition according to claim 1 , which contains a least one co-cross-linking agent based on an epoxy resin and/or a β-hydroxyalkylamide different from B).
25. A method for production of a powder-lacquer composition comprising coextruding in the molten state a composition comprising the following components at a temperature between 80 and 150° C.:
A) at least one carboxylate-group-containing polymer having an acid number of 10 to 250 mg KOH/g and a glass transition temperature T g higher than 40° C.,
B) at least one β-hydroxyalkylamide having two or three or four 3-hydroxyalkylamide groups per molecule of formula I
where
R 1 , R 2 : independently of one another denote the same or different radicals, selected from alkyl radicals, cycloalkyl radicals, aryl radicals, aralkyl radicals or alkenyl radicals having 1-24 carbon atoms, wherein the radicals may also contain heteroatoms and/or functional groups and wherein R 1 may also be hydrogen,
and wherein R 2 may also be
where R 3 : independently of one another denote the same or different radicals, selected from hydrogen, alkyl radicals, cycloalkyl radicals, aryl radicals, aralkyl radicals or alkenyl radicals having 1-24 carbon atoms, wherein the radicals may also contain heteroatoms and/or functional groups and wherein two or more R 3 substituents may be linked to one another to form rings;
wherein the β-hydroxyalkylamides exist in solid form below 150° C.;
C) optionally, at least one processing aid and/or additive;
wherein the ratio of β-hydroxyalkylamide groups to the carboxylate groups ranges between 0.5:1 and 1.5:1.
26. A process comprising coating the powder-lacquer composition according to claim 1 on a substrate, wherein the coating has a matte surface, with a specular gloss according to DIN 67530/ISO 2813 of <50 at an angle of incidence of 60.