| 摘要 |
PROBLEM TO BE SOLVED: To obtain an odorless cross-liniked polyethylene resin foam improved in softness, strengths, and chemical stability by irradiating a foamable sheet contg. a specific polyethylene resin and a blowing agent with an ionizing radiation to cross-link the sheet and then foaming the cross-linked sheet. SOLUTION: Ethylene and anα-olefin are copolymerized in the presence of a metallocene compd. catalyst contg. a tetravalent transition metal under a pressure in the range from normal pressure to 100kg/cm<2> at -100 to 300 deg.C to give a polyethylene resin having an apparent density of 0.84-0.95g/cc, one crystal melting peak when measured with a differential scanning calorimeter, and a temp. width from the crystal melting peak temp. to the completion of melting of all the crystals of 20 deg.C or lower. The resin in an amt. of 100 pts.wt. is compounded with 1.5-33 pts.wt. blowing agent, formed into a sheet, cross- linked by exposing to an ionizing radiation in a dose of 1-15Mrad, and heated to the decomposition point of the blowing agent or higher, thus giving a cross- linked polyethylene resin foam having an apparent density of 0.02-0.33g/cc and a gel fraction of 3-70%.
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