| 摘要 |
PURPOSE:To obtain the subject foamed material having improved formability, containing bubbles having a specific form and useful as a filler for interior trim of automobile, etc., by heating a crosslinked polyolefin resin sheet at a temperature above the softening point and stretching the sheet in lateral and longitudinal directions to effect the foaming of the resin. CONSTITUTION:A resin sheet is produced by adding azodicarbonamide, etc., as a foaming agent and divinylbenzene as a crosslinking agent to a polyethylene resin and a polypropylene resin, etc., and kneading the mixture with an extruder. The sheet is irradiated with electron ray to obtain a crosslinked polyolefin resin sheet 1. The sheet is foamed by heating at a temperature above the softening point with a hot air foaming oven 2 and the foamed material 5 is stretched in lateral direction and longitudinal direction with a stenter 3 and a chilled roll 4 to obtain the objective foamed material having a formability (H/L) satisfying the formula 1 (H is drawing depth in heat-forming; L is drawing diameter in heat-forming) and a bubble shape satisfying the formula II (LMD is bubble diameter of the foamed material in longitudinal direction; LZD is bubble diameter of the foamed material in the direction of thickness) and the formula III (LTD is bubble diameter in the lateral direction of the foamed material). |
