POLYESTER AND ITS PRODUCTION

摘要

PROBLEM TO BE SOLVED: To produce a polyester suitable as a container for beverages which are thermally sterilized and filled by drawing blow molding of a premolded product in the polyester produced by using an antimony catalyst. SOLUTION: This polyester contains (1) ethylene terephthalate units as a main constituent component, has (2) 0.6-0.9 dL/g intrinsic viscosity, (3) 0.8-2.0 mmol/kg content of antimony element and manifests (4) >=160 deg.C heat-up crystallization peak temperature and <=170 deg.C cooling crystallization peak temperature or the cooling crystallization peak temperature absent and (5) <=1×10-2 spherulites/μm2 number of spherulites in the polyester heated from normal temperature up to 120 deg.C and <=1×10-3 spherulites/μm2 number of spherulites in the polyester cooled from 300 deg.C to 200 deg.C.