Process for producing an open cell foam

Claim 1

A process for producing an open cell foam, wherein the open cell ratio ranges from about 50% to about 98% of the total void volume, which comprises irradiating a thermoplastic resin polymer blend composition comprising (a) a thermoplastic resin polymer blend including 1,2-polybutadiene, wherein the thermoplastic resin polymer responds with difficulty to an ultraviolet wave length of about 254 to about 400 mμ, the 1,2-polybutadiene being present in an amount of about 10 to about 90% by weight to the total weight of 1,2-polybutadiene and blended thermoplastic resin polymer, the 1,2-polybutadiene having not less than about 70 mol% 1,2-bonds, a molecular weight of not less than about 50,000, a degree of crystallinity of about 10 to about 50%, and a syndiotactic stereospecificity of 20% or higher, (b) a photosensitizing agent and (c) a thermally decomposable foaming agent with ultraviolet light of a wavelength of about 254 to about 400 mμ to cross-link the 1,2-polybutadiene, and subsequently foaming the composition at a temperature higher than the softening point of the 1,2-polybutadiene and that of the thermoplastic resin polymer blended therewith and higher than the decomposition temperature of the foaming agent.