EPOXY FUNCTIONAL POLYESTER RESINS, PROCESS FOR THEIR PREPARATION, AND OUTDOOR DURABLE COATING COMPOSITIONS COMPRISING THEM

摘要

An isocyanate-modified epoxy-functional polyester is prepared by the reaction of an epihalohydrin in the presence of a base with a carboxyl-functional polyester resin (II) obtained by reacting (a) at least one aromatic or (cyclo)aliphatic dicarboxylic acid A having aromatic or secondary carboxyl groups, or the anhydride thereof, (b) at least one diol B having primary or secondary hydroxyl groups, (c) compound C1 having one monofunctional primary or secondary hydroxyl group and/or at least one compound C2 having one primary or secondary hydroxyl group and one tertiary aliphatic carboxyl group, and, optionally, (d) a dihydroxymonocarboxylic acid having a tertiary aliphatic carboxyl group and two aliphatic hydroxyl groups, and/or (e) a trihydroxyalkane (E1) or tetrahydroxyalkane (E2), to produce an epoxy-functional polyester whose terminal hydroxyl groups are reacted with an isocyanate.