| 摘要 |
PROBLEM TO BE SOLVED: To obtain the subject aliphatic polyester copolymer excellent in crushability, powder-forming property, etc., in addition to biodegradability by subjecting an aliphatic diol to polycondensation with an aliphatic dicarboxylic acid, etc., and a lactone, etc., and specifying weight average molecular weight of the resultant polycondensation product. SOLUTION: (A) An aliphatic diol [e.g. an aliphatic diol of the formula HO-(CH2)1-OH (1 is 2-4)] is subjected to polycondensation with (B) an aliphatic dicarboxylic acid (anhydride or diester compound) [e.g. an aliphatic dicarboxylic acid of the formula HOOC-(CH2)m-COOH (m is 2-8) and (C) (i) a lactone [e.g. a compound of formula I (n is 2-5)] and/or (ii) a hydroxycarboxylic acid [e.g. a compound of formula II (X is H or methyl)] in an amount of 1-15 pts.wt. based on 100 pts.wt. copolymer to provide the objective copolymer having 1,500-20,000 weight average molecular weight(Mw) and 1.5-8.0 ratio (Mw/Mn) of Mw to number average molecular weight (Mn).
|
