| 摘要 |
PURPOSE:To improve the mechanical strength, by fillig a mold, which can be closed, but not be tightly closed, with polypropylene resin prefoamed particles, and heating the prefoamed particles to be molded into a body having a density of 0.06-0.3g/cm<3>, and a cell membrane thickness of 1-50mu. CONSTITUTION:The prefoamd particles are produced by incorporating 5- 30pts.wt. volatile foaming agent into 100pts.wt. polymer such as ethylene/propylene random copolymer, propylene monopolymer, etc. As said volatile foaming agent, aliphatic hydrocarbons such as propane, butane, etc. and cycloaliphatic hydrocarbons such as cyclobutane, etc. can be used. The prefoamed particles are matured at normal temperature under normal pressure, and then are matured under pressure to be provided with an internal pressure of 0.3-5kg/cm<2>G, and the mold, which can be closed, but not be tightly closed, is filled with the prefoamed particles, and the preforamed particles are heated and expanded using steam of 2-5kg/cm<2>G to obtain a molded body having a density of 0.06-0.3g/ cm<3>, and a cell membrane thickness of 1-50mu. |
