초록 ▼

A cable-sheating composition and its use as outer sheath for a power cable or a communication cable are disclosed. The cable-sheating composition is a multimodal, preferably bimodal, mixture of olefin polymers, preferable ethylene plastics, having a density of about 0.915-0.955 g/cm.sup.3 and a melt

A cable-sheating composition and its use as outer sheath for a power cable or a communication cable are disclosed. The cable-sheating composition is a multimodal, preferably bimodal, mixture of olefin polymers, preferable ethylene plastics, having a density of about 0.915-0.955 g/cm.sup.3 and a melt flow rate of about 0.1-0.3 g/10 min, said olefin polymer mixture comprising at least a first and a second olefin polymer, of which the first has a density and a melt flow rate selected from (a) about 0.930-0.975 g/cm.sup.3 and about 50-2000 g/10 min and (b) about 0.88-0.93 g/cm.sup.3 and about 0.1-0.8 g/10 min. Preferably, the olefin polymer mixture has been obtained by coordination-catalyzed polymerization of at least one .alpha.-olefin in several stages, preferably two stages consisting of a loop reactor/a gas-phase reactor or a gas-phase reactor/a gas-phase reactor, through polymerization or copolymerization of ethylene in the first stage and copolymerization of ethylene with butene, 4-methyl-1-pentene, 1-hexene or 1-octene in the second stage.

대표청구항 ▼

[ What is claimed is:] [1.]1. A method for using a cable-sheathing composition comprising:applying a cable-sheathing composition as an outer sheath for a power cable, wherein the cable-sheathing composition comprises a multimodal molecular weight distribution ethylene polymer mixture obtained by pol

[ What is claimed is:] [1.]1. A method for using a cable-sheathing composition comprising:applying a cable-sheathing composition as an outer sheath for a power cable, wherein the cable-sheathing composition comprises a multimodal molecular weight distribution ethylene polymer mixture obtained by polymerization of ethylene in more than one stage, the ethylene polymer mixture having a density of about 0.915-0.955 g/cm.sup.3 and a melt flow rate of about 0.1-3.0 g/10 min, said ethylene polymer mixture comprising at least a first and a second ethylene polymer, of which the first has a density and a melt flow rate selected from the group consisting of: (a) about 0.955-0.975 g/cm.sup.3 and about 100-1000 g/10 min and (b) about 0.88-0.93 g/cm.sup.3 and about 0.01-0.8 g/10 min., wherein the multimodal molecular weight distribution ethylene polymer mixture after extrusion as a cable-sheathing at 180.degree. C. or 210.degree. C. a shrinkage according to UNI-5079 of 1% or less when held at 23.degree. C. for 24 hours and a shrinkage of 1% or less when held at 100.degree. C. for 24 hours.