| 摘要 |
A semiconducting composition for electric cables, an electric cable incorporating the composition, and a method of producing a cross-linked semiconducting layer of an electric cable are disclosed. The semiconducting composition comprises, based on the total weight of the composition,(a) 50-90% by weight of an ethylene copolymer,(b) carbon black in an amount at least sufficient to make the composition semiconducting,(c) 0-8% by weight of a peroxide cross-linking agent,(d) 0-8% by weight of conventional additives,characterised in thatthe ethylene copolymer (a) is a heterogeneous ethylene-alkyl(meth)acrylate copolymer, which besides ethylene moieties comprises 2-10 mole % of an alkyl(meth)acrylate comonomer moiety, chosen among methyl(meth)acrylate, ethyl(meth)acrylate, (iso-)propyl(meth)acrylate and butyl(meth)acrylate, and the melting point of which is at least 95° C. and is higher than (108.5-1.7x(mole % of alkyl (meth)acrylate comonomer)) degree centigrade. The copolymer is preferably obtained by high pressure radical polymerisation in a tubular reactor. |
