| 摘要 |
PURPOSE:To stably produce prefoamed particles without any specific treatment for applying an internal pressure by using a base resin comprising a non-crosslinked, linear, low-density polyethylene resin which has a crystalline structure which exhibits two endothermic peaks in the DSC curve obtained by differential scanning calorimetry. CONSTITUTION:Out of non-crosslinked, linear, low-density polyethylenes (LLDPE and ethylene/4-10C alpha-olefin copolymers, wherein the content of the alpha-olefin is generally 3-25wt.% with 6-20% thereof especially preferred.), one which has a crystalline structure which exhibits two endothermic peaks in the DSC curve obtained when the temperature of 1-5mg of the resin is increased to 220 deg.C at a rate of 10 deg.C/min by a differential scanning calorimeter, then decreased at a rate of 10 deg.C/min, and again increased to 220 deg.C at a rate of 10 deg.C/min is used as formable non-crosslinked, linear, low-density polyethylene resin. In order to produce prefoamed particles for molding in a mold from the resin, the resulting resin is dispersed in water together with a foaming agent in a sealed container, the dispersion is kept under heating to allow the foaming agent to impregnate into the resin particles, and then the resin particles are released from the container into a low-pressure atmosphere, thereby allowing them to foam. |
