| 摘要 |
PURPOSE:The titled crosslinked copolymer excellent in impulse breakdown resistance, AC breakdown resistance, inhibition of deterioration due to water tree, flexibility, moldability and inhibition of low tie tree generation, comprising a crosslinked copolymer of ethylene with N-vinylpyrrolidone. CONSTITUTION:An ethylene copolymer of a number-average MW >=1,000 is obtained by radical-polymerizing ethylene with 0.0015-5mol% N-vinylpyrrolidone at a temperature >=120 deg.C and a pressure >=500kg/cm<2> in the presence of a catalyst (e.g., t-butyl peroxypivalate). 100pts.wt. composition formed by mixing this copolymer with, optionally, a thermoplastic resin (e.g., PE) is mixed with 0.5-4pts.wt. chemical crosslinking agent (e.g., dicumyl peroxide) and crosslinked to obtain an electrical-insulating crosslinked ethylene copolymer having an N-vinylpyrrolidone unit content of 0.005-10mol% and a gel content (according to the method of measurement as stipulated by JIS C3005) >=40%. |
