PROCESS FOR PRODUCING POLYMER FOAM BY EXPANSION COMPRISING CELL CREATING STEP AND FOAM FORMING STEP, AND POLYMER FOAM PRODUCED THEREBY

摘要

PURPOSE: Provided are a process for producing a polymer foam having an excellent surface appearance and a higher expansion proportion, and a polymer foam produced thereby. CONSTITUTION: The polymer foam is produced by the process comprising: (I) a melting step of melting a thermoplastic resin composition by heating; (II) a gas feed step of quantitatively supplying an inert gas into the molten resin composition; (III) a kneading step of mixing and kneading the inert gas and the molten resin composition; (IV) a cooling step of cooling the kneaded material; and (V) an expansion step of expanding the cooled kneaded material, wherein the expansion step (V) comprises (V-a) a cell creating step of producing cells and (V-b) a foam forming step of performing growth of the created cells and smoothening of the surfaces thereof, preferably by employing a die.