| 摘要 |
PROBLEM TO BE SOLVED: To provide a foam having uniform fine closed cells and improved in flexibility, elasticity and mechanical strength by using a polymerization catalyst comprising a metallocene compound containing a tetravalent transition metal to give an ethylene resin having a specified density and subjecting the resin to foaming. SOLUTION: Ethylene and, if necessary, anα-olefin are (co)polymerized in the presence of a polymerization catalyst consisting of a metallocene compound containing a tetravalent transition metal and a cocatalyst comprising, e.g. methylaluminoxane or a boron compound under a normal pressure to 100 kg/cm<2> at -100 to 300 deg.C to give an ethylene resin having a density of 0.840-0.890 g/cc, preferably 0.850-0.890 g/cc. 100 pts.wt. of this resin is blended with 1-25 pts.wt., preferably 2-20 pts.wt., heat-decomposable foaming agent and 0.1-10 pts.wt. crosslinking aid. The blend is melted and kneaded at a temperature at which the foaming agent does not decompose, and extruded to give a foamable sheet, which is crosslinked by ionizing radiation and then heated to foam.
|
