| 摘要 |
PURPOSE:To obtain a multi-layer sheet for sheet molding which has well- balanced PP/PET molding properties by laminating polypropylene resin (PP) and polyester resin (PET) of specific crystallization speed using DSC technique. CONSTITUTION:A multi-layer sheet for sheet molding consists of PP and PET which has a crystallization speed of one min. or longer using DSC technique. PET does not become crystallized easily due to the deterioration of crystallization speed of PET. Therefore, the tensile elongation of PET does not deteriorate of a PP/PET laminated sheet is molded within a temperature range suited for PP molding. As a result, troubles such as cracking of the sheet during molding process and the failure of the sheet to elongate according to a mold are eliminated. Further, the well-balanced molding properties of PP and PET is ensured so that a satisfactory molded product is obtained. PET with a crystallization speed of one min. or less becomes crystallized within the optimal molding temperature range of PP and the molding properties of PET are inferior. For example non-elongatable polyethylene terephthalate has a crystallization speed of 10sec. or less. Subsequently it tends to become crystallized immediately, if it is heated, and as such, it is no longer molded satisfactorily. |
