| 摘要 |
PURPOSE:The titled crosslinked copolymer excellent in impulse breakdown resistance, AC breakdown resistance and inhibition of deterioration due to water tree, comprising a crosslinked copolymer of ethylene with a specified ethylenically alpha,beta-unsaturated acid halogenated alkyl ester. CONSTITUTION:Ethylene copolymer of a number-average MW >=1,000 is obtained by radical-polymerizing ethylene with 0.001-4mol% ethylenically alpha,beta-unsaturated acid halogenated alkyl ester of the formula (wherein R<1> is H or -CH3 and R<2> is a 1-15 C halogenated alkyl) at a temperature >=120 deg.C and a reaction pressure >=500kg/cm<2> in the presence of a catalyst (e.g., t-butyl peroxyisobutyrate). 100pts. wt. this copolymer 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 a halogenated alkyl ester group content of 0.005-10mol% and a gel content (according to the method of measurement as stipulated by JIS C3005) >=40%. |
