| 摘要 |
PURPOSE:To eliminate the necessity of cleaning vent holes and enhance productivity by mounting a vent sheet constituted of a sheet-shaped base of superior air permeation formed with fiber materials and thermoplastic resin films to be laminated on the inner surface of a mold and carrying out foam molding. CONSTITUTION:A vent sheet 1 is constituted of a sheet-shaped base 2 of 40g/m<2>, formed of fiber pulp as a material and a polyethylene film 3 as a thermoplastic resin film laminated on one surface of said base. Foaming raw liquid (raw material) mainly composed of polyurethane resin is injected into a cavity of a clamped mold 10 and foamed thereon. Air inside the cavity pushed out in foaming flows through micro-pores of the polyethylene film 3 of the vent sheet 1 together with the gas generated at the time of foaming, flows through the base 2 and further vent holes 11a of a top force 11 to be discharged out a system. On the other hand, the base 2 is not impregnated with a polyurethane foam 20 in the process of foaming, which is not entered into the vent holes 11a, either. |
