Plastic-jacketed tube, e.g. copper@ water pipe

摘要

A tube with a plastic jacket made of a polyethylene (PE)-based mixture contains: (a) 15-45 wt.% chalk as filler; (b) 8-30 wt.% elastomer-modified polyolefin as plasticiser; (c) 1-10 wt.% metal-free thermal stabiliser, and (d) PE homopolymers and copolymers with a content of at least 15 wt.%. The casing composition contains 25-35 wt.% (a), 10-18 wt.% (b) (especially elastomer-modified polypropylene, PE or polybutene), 1-3 wt.% (c), 0.5-3 wt.% pigment mixture for colouring, 0.2-1.5 wt.% lubricants and processing aids, and PE homo- and co-polymer mixture as above, preferably HDPE, LDPE and/or LLDPE. The jacket shows a thermal conductivity of 0.1-0.5 (preferably 0.16-0.35) W/m/K at 40 deg C, a heat distortion temperature of at least 105 deg C and an elongation at break (DIN 53455) of at least 680%; it also meets the fire resistance requirements for building materials Class B2 (DIN 4102). The plastic jacket is preferably fitted round a copper pipe.