| 摘要 |
PURPOSE:To prepare a molded item of a polyethylene terephthalate (PET) sheet which has so-called shape memory characteristics wherein the shape is returned to the heat-molded and crystallized molded shape by heating at a certain temp. and the shape of which can be changed after heating from the shape before heating. CONSTITUTION:In a method for molding a crystalline polyethylene terephthalate sheet wherein after a foamed or an unfoamed crystalline polyethylene terephthalate sheet 1 is softened by preheating, molding is performed in a heating mold 3 and at the same time, crystallization is performed to a specified degree of crystallization and thereafter, cooling and molding are performed in a cooling mold 4, the heating mold 3 and the cooling mold 4 have respectively a different mold face shape and a shape being different from the molded shape molded by the heating mold 3 is molded by the cooling mold 4. The preheating is performed in such a way that the degree of crystallinity does not exceed 18% and the crystallization is performed to the degree of crystallinity of 20-25% by molding in the heating mold 3. |
