| abstract |
The present invention economically provides a method and device for producing a high-viscosity polylactic acid foam molding material which is suitable for foam molding at a high expansion ratio, and a foam molded article having a high expansion ratio which is formed of said polylactic acid composition. A polylactic acid foam molding material having an MI value of 0.05-5, measured in accordance with JIS K7210 at 190° C. under a 21.6-kg load, is produced by physically or mechanically lowering the molecular weight and rebonding, in the presence of a supercritical inert gas, polylactic acid having a molecular weight in terms of polystyrene of 2,000,000 or higher by GPC measurement generated when three types of crosslinked polylactic acid (A), (B), and (C) having different component ratios of D and L isomers, obtained by reacting polylactic acid composed of D and L isomers with a crosslinking agent, are mixed in a weight ratio of 25-50:25-50:25-50 (where (A)+(B)+(C)=100) and the mixture is melted; and a foam molded article is produced by providing a grinding orifice on an injection molding machine or an extrusion molding machine, discharging from a die at a temperature from the softening point to 110° C., and foam molding. |