Thermosetting acrylic copolymer usable as a powder paint and method for producing the same

Claim 1

A thermosetting acrylic copolymer for the use as powder paint, which comprises (1) 3 to 30% by weight of at least one repeating unit of the formula (I): ##STR16## wherein R 1 represents a hydrogen atom or methyl group and R 2 represents an alkyl group having 1 to 8 carbon atoms or a cycloalkyl group having 6 to 8 carbon atoms, (2) 1 to 50% by weight of at least one repeating unit selected from the groups of the formulae (II) and (III): ##STR17## wherein R 1a represents a hydrogen atom or methyl group, R 3 represents an alkylene group having 2 to 6 carbon atoms, R 4 represents an aliphatic group containing or not containing a carboxyl group and having 2 to 12 carbon atoms or an aromatic group containing or not containing a carboxyl group and having 6 to 12 carbon atoms, R 5 represents an aliphatic group containing or not containing a hydroxyl group and having 1 to 18 carbon atoms or an aromatic group containing or not containing a hydroxyl group and having 6 to 18 carbon atoms, and n represents an integer of 1 or 2, and (3) 20 to 96% by weight of at least one repeating unit of the formula (IV): ##STR18## wherein R 1b represents a hydrogen atom or methyl group, and X represents an ester, nitrile, amide, R 6 COO-- in which R 6 represents an alkyl group having 1 to 18 carbon atoms, glycidylester, glycidylether or aromatic group having 6 to 18 carbon atoms or a halogen atom, said polymer having a weight average molecular weight of 4,000 to 30,000 and being in a solid state at normal temperature.

Claim 7

A method for producing a thermosetting acrylic polymer for the use as powder paint, which comprises copolymerizing, by way of a suspension copolymerization in an aqueous medium at a pH of 7 or less, (1) 3 to 30% by weight of at least one comonomer of the formula (I'): ##STR19## wherein R 1 represents a hydrogen atom or methyl group and R 2 represents an alkyl group having 1 to 8 carbon atoms or a cycloalkyl group having 6 to 8 carbon atoms, (2) 1 to 50% by weight of at least one comonomer selected from the compounds of the formulae (II') and (III'): ##STR20## wherein R 1a represents a hydrogen atom or methyl group, R 3 represents an alkylene group having 2 to 6 carbon atoms, R 4 represents an aliphatic group containing or not containing a carboxyl group and having 2 to 12 carbon atoms or an aromatic group containing or not containing a carboxyl group and having 6 to 12 carbon atoms, R 5 represents an aliphatic group containing or not containing a hydroxyl group and having 1 to 18 carbon atoms or an aromatic group containing or not containing a hydroxyl group and having 6 to 18 carbon atoms, and n represents an integer of 1 or 2, and (3) 20 to 96% by weight of at least one comonomer of the formula (IV'): ##STR21## wherein R 1b represents a hydrogen atom or methyl group, and X represents an ester, nitrile, amide, R 6 COO-- wherein R 6 represents an alkyl group having 1 to 18 carbon atoms, glycidylester, glycidylether or aromatic group having 6 to 18 carbon atoms or a halogen atom, in the presence of a hydrophobic radical polymerization initiator and chain transfer agent, catalyst, to form a copolymer having a weight average molecular weight of 4,000 to 30,000 and being in solid state at a normal temperature.

Claim 8

A method for producing a thermosetting acrylic polymer for the use as powder paint, which comprises copolymerizing, by way of a suspension copolymerization in an aqueous medium at a pH of 7 or less, (1) 3 to 30% by weight of at least one comonomer of the formula (I'): ##STR19## wherein R 1 represents a hydrogen atom or methyl group and R 2 represents an alkyl group having 1 to 8 carbon atoms or a cycloalkyl group having 6 to 8 carbon atoms, (2) 1 to 50% by weight of at least one comonomer selected from the compounds of the formulae (II') and (III'): ##STR20## wherein R 1a represents a hydrogen atom or methyl group, R 3 represents an alkylene group having 2 to 6 carbon atoms, R 4 represents an aliphatic group containing or not containing a carboxyl group and having 2 to 12 carbon atoms or an aromatic group containing or not containing a carboxyl group and having 6 to 12 carbon atoms, R 5 represents an aliphatic group containing or not containing a hydroxyl group and having 1 to 18 carbon atoms or an aromatic group containing or not containing a hydroxyl group and having 6 to 18 carbon atoms, and n represents an integer of 1 or 2, and (3) 20 to 96% by weight of at least one comonomer of the formula (IV'): ##STR21## wherein R 1b represents a hydrogen atom or methyl group, and X represents an ester, nitrile, amide, R 6 COO-- wherein R 6 represents an alkyl group having 1 to 18 carbon atoms, glycidylester, glycidylether or aromatic group having 6 to 18 carbon atoms or a halogen atom, in the presence of a hydrophobic radical polymerization initiator and chain transfer agent, catalyst, to form a copolymer having a weight average molecular weight of 4,000 to 30,000 and being in solid state at a normal temperature.