| 摘要 |
PURPOSE:To certainly lower gas permeability by injecting a multilayered parison by a single-layer die. CONSTITUTION:The resin charged in an accumulator is extruded to a die by a plunger 32. When the plunger 32 is pushed out, the flow speed of the resin in the accumulator 30 becomes slow in the vicinity of the inner wall, surface of the accumulator and becomes fast at the center part thereof to form parabolic flow speed distribution such that the resin at the central part is precedingly extruded in an extrusion direction and the flow speed thereof becomes slow as the resin reaches the inner wall surface of the accumulator. When the plunger 32 is further pushed out, the central part of the resin flows more precedingly and the inclination of the laminating area of a main material 44M and a first auxiliary material 44S becomes large. Finally, the laminating area of the first material 44M and the first auxiliary material 44S becomes the so-called grainlike state of becoming almost parallel to the extrusion direction during a period when the layers of both materials are passed through the resin passage 34 to be supplied to the die 10. |
