| 摘要 |
A novel polyhydroxy oligomer crosslinkable with polyisocyanates to form a coating composition adapted for use as an automotive topcoat which upon curing forms a hard, glossy, durable coating with outstanding durability and excellent resistance to solvents and water. The coating composition comprises: (A) a polyhydroxy oligomer having a number average (Mn) molecular weight of between about 250-2000 and being the reaction product of: (i) an ester having pendant hydroxyl and carboxyl functionality and being made by reacting (a) a C3-C10 aliphatic branched diol, and (b) an alkyl hexahydrophthalic anhydride; and (ii) a C2-C10 monomer, having reactive functionality capable of esterifying said carboxyl functionality of said ester; (B) a polyisocyanate crosslinking agent having two or more reactive isocyanate groups per molecule; and (C) 0-50 weight percent based on the total weight of (A), (B) and (C) of a hydroxy functional additive having a number average weight (Mn) of between about 150-6000.
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