| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for preparation of a multilayer preform wherein recovered polyester resin is reused effectively and also which prevents elution of impurities in the recovered polyester resin into contents and whitening in external appearance. SOLUTION: In this method for preparation of a multilayer preform 10, an inner layer 16 being a primary molded body is formed by injecting virgin polyester resin, an intermediate layer 17 being a secondary molded body is formed by injecting recovered polyester resin onto the outer surface of the primary molded body and an outer layer 18 being a tertiary molded body is formed by injecting the recovered polyester resin or the virgin polyester resin onto the outer surface of the secondary molded body, by using multistag injection molding equipment. According to this constitution, the recovered polyester resin is reused effectively and also a multilayer preform being free of whitening is obtained. |
