| 摘要 |
PURPOSE:To remove efficiently the gas generated in a material and to form an excellent foamed piece by a method wherein stock moldings made by a compounded resin formed by kneading with a blowing agent is mounted on a mold, and a vent hole is formed on the upper side of the mold to heat the formed piece. CONSTITUTION:Blowing agent is added to a material resin composed of vinyl chloride polymer or copolymer with vinyl acetate or the like and they are kneaded sufficiently. The kneaded material is molded by an extruding machine or a pair of calender rolls into rod or plate stock material and cut to element pieces having the specified shape. Raw molded pieces P1 are mounted on the mold and vent holes 30, 30... in the form of a pin hole are formed on the upper side at a suitable interval to heat the pieces. Thus, the gas generated by the internal expansion of the material followed by self-exothermic decomposition of the blowing agent is conducted to the upper part, released outside through the mold face between molds 27, 28 so that generation of void such as air voids etc. are prevented. |
