| 摘要 |
PURPOSE:To obtain a foamed product with stable expansion ratio, while removing the tendency to volatilize blowing agent by heating the mixture in which rubber plastic and microcapsule like blowing agent are mixed, to foam said mixture. CONSTITUTION:Rubber plastic and micro capsule like blowing agent are kneaded by an extruder, a kneader or a homogenizing roll. This kneaded material is preferably formed into pellet, and this pellet is introduced into a mold and heated, whereby the micro capsule like blowing agent is foamed, while causing the viscosity of raw material to be in the range suitable for foaming. As the rubber plastic to be used, butadiene rubber, polyethylene, ethylene-vinyl acetate copolymer and ionomer, etc. are useful. As the micro capsule like blowing agent to be used, following agent is useful. it is blowing agent of hydrogen carbide series such as isobutane enclosed with the polymer with high gas barrier-property such as vinylidene chloride and/or acrylonitrile copolymer. By such foaming process, a foamed product with stable expansion ratio and without the tendency to volatilize the blowing agent of hydrogen carbide series. |
