| 摘要 |
PROBLEM TO BE SOLVED: To obtain loose cushioning material excellent in cushioning properties (restoring properties) and, moreover, in biocomposability at a low cost by expanding a material, whose main raw material is starch containing a specific amount of amylose, by specific times, and forming the material into a shape of a cylindrical body having a specific diameter and length and having both ends closed. SOLUTION: The material whose main raw material is starch containing 45wt.% of amylose is foam-molded to increase by 30-60 times and to obtain a rose-like expanded cushioning material 8 having a shape of a cylindrical body measuring 13-25mm in diameter and 20-65mm in length, wherein the central part of the column is a cavity 11 and both ends of the cylindrical body are closed. The expanded cushioning material 8 of this type is manufactured by such a method that the material is heated, kneaded and compressed by an extruder, is discharged from a discharge port of dies to be expanded, and is cut in a fixed size immediately after discharge. In this instance, a ratio of the diameter of the discharge port to the length of a land is set to 1 to (1-1) to (1-1.75), and the center of the discharge port is so disposed as to be positioned on a shaft of a screw of the extruder, thereupon the material is discharged from the dies at a discharge temperature of 165-195 deg.C and under a discharge pressure of 45-100kg/cm<2> . |
