Abstract: A foamable resin composition according to the present invention comprises starch, an aliphatic polyester and water, and wherein 10 to 40 parts by mass of the water and 10 to 80 parts by mass of the aliphatic polyester are included with respect to 100 parts by mass of the starch. The foamable resin composition preferably comprises 3 to 60 parts by mass of a glycerin with respect to 100 parts by mass of the starch. The whole composition of the foamable resin composition is made of a biodegradable raw material, and the molded product of the composition has excellent water resistance and favorable moldability, is free from problems in mechanical characteristics such as strength, and also has a cost advantage.

Abstract: A foamable resin composition according to the present invention comprises 10 parts by weight or less, preferably 0.5 to 8 parts by weight of a biodegradable resin and/or polyolefin resin, 10 to 30 parts by weight of water and 0.01 to 5 parts by weight of an inorganic filler, with respect to 100 parts by weight of a modified starch. The modified starch is preferably at least one of oxidized starches, esterified starches, acetylated starches and cationic starches. The foamable resin composition can maintain strength, etc., of the foamed body obtained at a practical level even though the amount of the biodegradable resin and/or polyolefin resin is reduced as much as possible, and has a cost advantage.