| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for producing a biodegradable foam useful as a highly expanded cushion material for packing, which has excellent water resistance and compostability, by kneading a composition obtained by mixing a polyester-based biodegradable resin, an organic peroxide, and a chemical foaming agent, crushing the obtained mixture to give powder, followed by molding the obtained powder in a mold. SOLUTION: This method comprises the following steps: (1) a composition obtained by mixing (A) a polyester-based biodegradable resin (e.g. polylactate), (B) an organic peroxide (e.g. benzoyl peroxide), and (C) a chemical foaming agent (preferably, N,N'-dinitropentamethylenetetramine-based one or sodium bicarbonate-based one) is mixed to give a composition. (2) the obtained composition is kneaded. (3) the obtained preparation is crushed to give powder. (4) the obtained powder is molded by foaming in a mold. Preferably 0.01-1 pt.wt. of component B and usually 20-50 pts.wt. of component C are mixed with 100 pts.wt. of component A. Preferably, 5-30 pts.wt. of cellulose fibers can further be mixed with 100 pts.wt. of component A in order to enhance biodegradability and compostability. It is preferable that an average particle size of the composition is 0.1-3 mm. |
