Patent ID: 6500508
Filing Date: 2002-12-31
Classification: C08K,H01B,Y10S,Y10T

Abstract:
An insulating tube as produced by shaping into a tube then cross-linking it with a flame retardant resin composition comprising:(a) a thermoplastic polyolefinic resin having a density of smaller than 0.89g/cm3, prepared by copolymerizing ethylene and non-polar &agr;-olefin in the presence of a single-site metallocene catalyst; (b) a halogen-containing flame retardant; and (c) zinc oxide; wherein the cross-linked flame-retardant resin composition has an initial tensile strength of n less than 1.05 kg/mm2 and an initial elongation of not less than 100%, as stipulated in the UL Standards; and wherein the resin composition has a flame resistance that satisfies all the following three requirements in the VW-1 perpendicular combustion test: 1) the longest burn time for the sample is within 60 seconds; 2) the kraft paper attached to the upper side of the sample is not burnt; and 3) the absorbent cotton disposed below the sample is not burnt by the burnt droppings of the sample; wherein the resin composition has modules of tensile elasticity of not larger than 10kg/cm2 and has a specific dielectric constant less than 3.3, and wherein the resin composition comprises about 20 to about 60 parts by weight of halogen-containing flame-retardant and about 5 to about 20 parts by weight of zinc oxide, based upon 100 parts by weight of the thermoplastic polyolefinic resin.