COPOLYESTER RAW MATERIAL FOR AMORPHOUS FILM, HEAT-SHRINKABLE POLYESTER-BASED FILM, HEAT-SHRINKABLE LABEL, AND PACKAGE

摘要

[Problem] To provide: a heat-shrinkable polyester film which has a high thermal shrinkage rate in a primary shrinkage direction, has a low thermal shrinkage rate in a non-shrinkage direction and exhibits little change in shrinkage rate after aging; and a raw material for producing the heat-shrinkable polyester film. [Solution] A copolyester raw material for an amorphous film, which is characterized by satisfying requirements (1)-(4) and being used to produce a film. (1) The raw material contains ethylene terephthalate as a primary constituent component, and if the total amount of glycol components among all polyester resin components is taken to be 100 mol%, the content of neopentyl glycol is 15-30 mol%. (2) The content of constituent units derived from diethylene glycol is 7-15 mol% relative to a total of 100 mol% of glycol components among all polyester resin components. (3) The limiting viscosity of the raw material is not less than 0.60 dl/g and less than 0.70 dl/g. (4) The glass transition temperature is 60-70°C.