| 摘要 |
PROBLEM TO BE SOLVED: To provide an aliphatic polyester which is produced as a high-molecular-weight one without using a chain extender such as an isocyanate compound or a carbonate compound and is excellent in moldability of injection molding, blow molding and extrusion molding, thermal stability and mechanical properties such as tensile properties. SOLUTION: The aliphatic polyester comprises an aliphatic diol unit, an aliphatic carboxylic acid unit and an organic acid unit having a pKa value of 3.7 or below at 25°C, wherein a content of carbonate bond included in the polyesters is less than 1 mol%, a content of urethane bond is less than 0.06 mol%, a content of aliphatic monooxymonocarboxylic acid unit is less than 0.02 mol%, a content of phosphorus atom derived from phosphorus-containing compound selected from among organic phosphinic acids, organic phosphonic acids and hydrogen phosphate salts is less than 10<SP>-9</SP>mol%, based on the whole monomer units constituting the polyester, and a reduced viscosity (ηsp/C) is 1.6 or more. COPYRIGHT: (C)2010,JPO&INPIT
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