| 摘要 |
PURPOSE:To obtain efficiently a multi-layer drawn bottle and to improve the heat resistance, by utilizing a temp. distribution of a preform on the cooling process after injection molding for controlling the temp. of the perform and by selecting a resin composition and a position of a core layer fit thereto. CONSTITUTION:A resin composition having a higher glass transition temp. TgH and a resin composition having a lower glass transition temp. TgL, both selected from a resin composition consisting of 99-20pts.wt. of polyethylene terephthalate and 1-80pts.wt. of aromatic polyester, are respectively a core and a skin layer forming a preform. The surface temp. of the preform on the cooling process are controlled in a temp. range satisfying the equation TgL< the surface temp. of the preform <TgL+50 deg.C (1) and biaxial drawing-blowing is carried out. The difference between the glass transition temp. of two resin compositions selected here satisfies the equation (2) and the melt viscosity of the resin composition for the core layer is smaller than that of the resin composition for the skin layer. X in the equation (2) shows a half of the thickness of the core layer. |
