The invention is directed to two-component coating compositions comprising
A) at least one hydroxy-functional (meth)acrylic copolymer having an OH value from 160 to 200 mg KOH/g and a weight average molecular weight Mw from 2,500 to 30,000 and
B) at least one polyisocyanate cross-linking agent;
wherein the hydroxy-functional (meth)acrylic copolymer A) is obtained by AI) free-radically copolymerizing a monomer mixture comprising
a) at least one hydroxy functional free-radically copolymerizable olefinically unsaturated monomer,
b) at least one cycloaliphatic ester of a free-radically copolymerizable olefinically unsaturated carboxylic acid and
c) at least one additional free-radically copolymerizable olefinically unsaturated monomer which is different from component a) and b) and
AII) reacting at least part of the hydroxyl groups of the hydroxy-functional (meth)acrylic copolymer obtained in step AI) with
d) at least one lactone compound;
wherein the hydroxy-functional (meth)acrylic copolymer obtained in step AI) has a glass transition temperature Tg of at least 50° C. and wherein said copolymer is free of epoxy-functional free-radically copolymerizable olefinically unsaturated monomers.
                            本发明涉及一种两组分涂料组合物,包括A)至少一种具有OH值为160至200mg KOH/g和重量平均分子量Mw为2,500至30,000的羟基官能团(甲基)
丙烯酸酯共聚物和B)至少一种多
异氰酸酯交联剂。其中,羟基官能团(甲基)
丙烯酸酯共聚物A)是通过AI)自由基共聚一种单体混合物获得的,该单体混合物包括a)至少一种羟基官能自由基共聚的烯烃不饱和单体,b)至少一种自由基共聚的环状脂肪族酯,该脂肪族酯是由自由基共聚的不饱和
羧酸和c)至少一种与组分a)和b)不同的自由基共聚的烯烃不饱和单体;AII)反应AI)步骤中获得的羟基官能(甲基)
丙烯酸酯共聚物的至少一部分羟基基团,与d)至少一种内酯化合物反应。其中,在步骤AI)中获得的羟基官能(甲基)
丙烯酸酯共聚物具有至少50℃的
玻璃化转变温度Tg,并且该共聚物不含环氧官能自由基共聚的烯烃不饱和单体。