Patent ID: 6537404
Filing Date: 2003-03-25
Classification: B29B,B29C,B29K,B29L,C08J,Y02W,Y10T

Abstract:
A method for manufacturing thermoplastic polyester resin foam comprising:a melting and kneading step for melting and kneading a composition comprising at least one moisture-containing recycled thermoplastic polyester resin, and a crosslinking agent selected from the group consisting of an acid dianhydride, a ring-opened compound thereof, and a compound having at least three carboxyl groups, in an extruder comprising at least one twin screw to obtain a molten resin, a moisture removing step for removing moisture in the molten resin by venting said molten resin under vacuum from said extruder to obtain a dehumidified molten resin, a foaming agent injecting step for injecting a physical foaming agent into the dehumidified molten resin to modify the dehumidified molten resin into a foaming molten resin, and an extrusion foaming step for extruding and foaming the foaming molten resin into a low pressure region to obtain thermoplastic polyester resin foam, wherein said recycled thermoplastic polyester resin is PET, having a foaming index of at least 0.4, or adjusted to have a foaming index of at least 0.4 , and the amount of the recycled thermoplastic polyester resin is not less than 26.8%, and up to 90.9% relative to the total amount of supplied materials except the foaming agent.