PRODUCTION OF BIODEGRADABLE RESIN FOAM

PURPOSE:To obtain the subject foam having a high expansion rate and closed cells by mixing water-containing starch, water-containing PVA resin, nonionic surfactant and an organic filler, then melting and foaming the mixture. CONSTITUTION:(A) A starch high polymer of 5 to 30wt.% water content such as potato starch or alpha-starch, (B) a vinyl alcohol resin of 5 to 30wt.% water content, preferably of 70 to 100 (mole) % of saponification degree and 700 to 3,000 polymerization degree, (C) a nonionic surfactant, (preferably polyoxyethylene alkylphenyl ether), preferably in an amount of 2 to 5wt.% of the composition, and (D) an organic filler (preferably vegetable fiber products), preferably in an amount of 5 to 30wt.% of the composition, are mixed so that the total water content is adjusted to 5 to 30wt.%, preferably 3 to 30wt.%, and the mixture is molten and foamed to give the objective foamed product. A thickener is preferably added to the composition.