| abstract |
PURPOSE: To prepare an elastic block copolyester useful as flexible parts and having improved heat resistance and chemical resistance, by reacting an aromatic poly- ester with a polyoxyethylene glycol and/or an aliphatic polyester. n CONSTITUTION: (1) A soft segment comprising (A) a polyoxyalkylene glycol having an average molecular weight of about 300W5,000 and the ratio of carbon atom number to oxygen atom number of 20W45, and/or (B) an aliphatic polyester (e.g. polytetramethylene adipate, etc.), is ester-exchanged with (2) a hard segment comprising (C) an aromatic polyester (e.g. polytetramethylene terephthalate, etc.) to give a polyester containing 20W80 wt% of the soft segment and having ≥ 20 wt.% of the ortho-chlorophenol-insoluble part. n COPYRIGHT: (C)1979,JPO&Japio |