| 摘要 |
PURPOSE:A composition comprising a vinyl chloride resin, a thermal decomposition type foaming agent and an acrylic resin is, after an organic foaming agent is forced into it in the extruder, extruded, foamed and molded to produce moldings that can give foamed products of uniformly fine cellular structure. CONSTITUTION:A resin composition comprising 100pts.wt. of a vinyl chloride resin, preferably a copolymer with vinyl acetate, 0.01-10pts. of a thermal decomposition type foaming agent for increasing cell uniformly, cell fineness and foaming degree such as azodicarboxylic acid amide and 0.5-30pts. of an acrylic resin for accelerating resin gelation and holding foamed gas, preferably methyl methacrylate polymer is fed to an extruder. Then 1-30pts. of an organic solvent foaming agent boiling at lower than 90 deg.C such as propane is forced into the half to completely gelling resin compositon and they are extruded, foamed and molded. After the foaming agent is forced into the extruder, the temperature is preferably lowered to a temperature that is more than 30 deg.C higher the softening point of the compositon and lower than the apparent gelation temperature and molding is conducted. |
