Patent ID: 8043539

Claim:
A method to manufacture a biodegradable molded article comprising the steps of: providing a slurry or dough molding material mainly made of starch or a derivative thereof and obtained by adding water therewith; providing a coating film distinct from the slurry or dough molding material and mainly made of a biodegradable plastic and having hydrophobicity; placing the slurry or dough molding material and the coating film into a mold having a given-shaped cavity to obtain a combination of the slurry or dough molding material and the coating film; and heating and molding the combination of the slurry or dough molding material and the coating film in the mold to mold the slurry or dough molding material through steam expansion, and at the same time soften and pressure-bond the coating film to a surface of a biodegradable expanded molded article obtained through steam expansion molding, wherein a mold made up of a pair of a convex mold and a concave mold being used; said mold has an exhaust hole; the molding material and the coating film being placed between the convex mold and the concave mold before the heating and molding; in the heating and molding step, a central part of the coating film being deformed by moving at least either one of the convex mold and the concave mold in a direction wherein these two molds fit together; at least while the coating film is being deformed, a relative moving speed of the convex mold to a plane formed by connecting a surface of non-deforming parts on an outer periphery of the coating film being maintained from 8 mm/s to 12 mm/s; and in the heating and molding step, a gas existing between the coating film and a surface of the mold is discharged out of the cavity through the exhaust hole.