HEAT-SEALABLE CAP FOR POLYESTER VESSEL AND VESSELS CAPPED WITH SAME

摘要

A method for heat sealing between a thermoplastic polyester vessel and a cap and heat-sealed vessels capable of resisting hot water treatment such as retort sterilization are disclosed. The heat-sealable cap to be used comprises a laminate of a heat-sealing layer containing as a major component a copolymer polyester resin having a softening point of 120 DEG C or above and a glass transition temperature of 30 to 85 DEG C, a metallic material, and an epoxy-phenol resin primer layer provided therebetween. The vessel to be used preferably has a heat-sealable portion comprising a thermoplastic polyester having a melting temperature of 200 DEG C or above in a crystalline state and being oriented to crystallize or thermally crystallized.