| 摘要 |
PURPOSE: A urethane-modified copolymeric polyester resin for a paint is provided, to improve corrosion resistance and processability. CONSTITUTION: The urethane-modified copolymeric polyester resin is prepared by reacting a polyester resin comprising a dicarboxylic acid as an acid component and an alkylene oxide group additive of bisphenol A as a polyvalent alcohol component with a diisocyanate compound in the equivalence ratio NCO/OH of 0.4-0.8, and has an OH value of 5-10 KOH mg/g. Preferably the polyester resin comprises 3-25 mol% of 1,4-cyclohexanedicarboxylic acid or its ester derivative in an acid component and 5-40 mol% of an alkylene oxide group additive of bisphenol A represented by the formula I in a polyvalent alcohol component, wherein R is an alkylene group of C2-C3; and m and n are identical or different each other and are 1 or 2 and 2<=m+n<=4.
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