| 摘要 |
PURPOSE:To obtain the subject foam, excellent in cushioning properties and flexibility and useful as a heat insulating material, etc., by mixing and melting a polybutene-1-based resin with a specific evaporation type foaming agent at a high temperature under a high pressure, subsequently extruding the melt under atmospheric pressure and releasing the pressure. CONSTITUTION:A polybutene-1-based resin and an evaporation type foaming agent such as propane (pressed thereinto in an amount of preferably 5-30 pts.wt. based on 100 pts.wt. resin) having 4-7 pts.wt., preferably 5.5-6.5 pts.wt. number of impregnation pts., when impregnated into the polybutene-1-based resin under conditions of 120 deg.C temperature and 10kg/cm<2>G pressure for 60min, are mixed and melted at a high temperature under a high pressure and extruded under atmospheric pressure. The pressure is then released to afford the objective foam. Furthermore, the aforementioned foam has 15-40kg/m<3> density, 0.2-1.5mm average cell diameter and >=10wt.% closed cell ratio. |
