| 摘要 |
PROBLEM TO BE SOLVED: To provide a biodegradable foam sheet needing no complicated process for its production, easy to transport or handle, and having high mechanical strength and good appearance, and to provide a method for producing the sheet. SOLUTION: This biodegradable foam sheet, which is made from a cellulose acetate resin, is thick and has plate rigidity. This foam sheet is produced by the following process: an expandable biodegradable resin composition prepared by compounding the cellulose acetate resin as the main component with a biodegradable plasticizer and water as the foaming agent is extruded via a T-die having a profile slit design with repeated wideness and narrowness and an enough lip width to obtain a thick sheet and concurrently expanded by the aid of the vaporizing expansive force of the water. This foam sheet thus produced has highly smooth surfaces with striated unevennesses of definite shape arranged regularly in line. The other objective method for producing the biodegradable foam sheet is provided as described above. |
