METHOD FOR PRODUCING POLYOLEFIN RESIN FOAM

PROBLEM TO BE SOLVED: To provide a method for producing polyolefin resin foam, capable of easily producing the foams having ≥5 times expansion rate without causing deformation after expansion. SOLUTION: The polyolefin resin foam is produced by mixing a material comprising a polyolefin resin, sodium hydrogencarbonate to be decomposed to generate carbonic acid gas and water when heated and an oxide of an alkali metal or an alkaline-earth metal, and heating the mixed material to foam the polyolefin resin with the carbonic acid gas generated by decomposition of the sodium hydrogencarbonate. Wherein the content of the oxide is determined to be 5-100 pts.mass per 100 pts.mass polyolefin resin. A crosslinking agent is preferably contained in the material. And cooling after heating and then re-heating at 50-120°C for 3-24 h is preferable. COPYRIGHT: (C)2007,JPO&INPIT