Method of adjusting expansion ratio of thermoplastic elastomer foam, method of foaming thermoplastic elastomer, and foam of thermoplastic elastomer

摘要

PURPOSE:To enable the control of expansion ratio of a foamed material in the foaming of a thermoplastic elastomer using water as a foaming agent preferable from the viewpoint of environment and cost by varying the melt ductility of the thermoplastic elastomer. CONSTITUTION:The expansion ratio of a foamed material is controlled in the foaming of a thermoplastic elastomer using water as a foaming agent by varying the melt ductility of the thermoplastic elastomer in a fluidized or plasticized state at the stage to generate or expand bubbles with steam preferably by adding a melt-ductility improving agent or varying the expansion foaming temperature. Concretely, e.g. in the case of using a polymer blend of PVC and a nitrobutadiene rubber as the thermoplastic elastomer, the expansion ratio of the elastomer can be varied by adding a polymer blend of polymethyl methacrylate and PVC as the melt-ductility improving agent.