Heat-sealed closure for polyester container

摘要

The present invention provides a strong heat seal to a thermoplastic polyester container which can withstand hot water treatment such as retorting, and to a heat sealed container. A heat-sealable closure is also provided. It is composed of a laminate consisting of a heat-seal layer comprising as a main component a copolymerized polyester resin having a softening temperature of 120 DEG C. and a glass-transition temperature of 30 DEG to 85 DEG C., a metal substrate, and an epoxy-phenol resin primer layer interposed between them. Preferably, the container has a heat seal portion composed of a thermoplastic polyester having a fusion temperature in the crystalline state of at least 200 DEG C. This polyester portion is oriented and crystallized or heat-crystallized.