Filler for polyethylene insulated communication cable - comprises a suspension of lightly crosslinked polystyrene in an aromatic liq. which swells the polymer

摘要

Fillers for polyolefin insulated matched telecommunications cables and cable couplings, consists of a suspension of fine pearl polymers of lightly crosslinked polystyrene with uniform or variable degree of crosslinking and a particle size of 0.1-200 mu m, esp. 0.1-100 mu m dispersed in an electrically high grade, chemically inert aromatic liq. a low vapour press. The liq. swells the polymer particles. The polymer is e.g. of styrene or ring-methylated styrene crosslinked with 0.5-25 wt.% of divinyl benzene. The aromatic liq. is e.g. dibenzyltoluene or dodecylbenzene. The compsn. pref. contains roughly equal proportions of the styrene polymer and the aromatic liq., opt. together with 0.05-1 wt.% of an amine or phenolic stabiliser such as N,N'-diphenyl-p-phenylenediamine or 4,4'-thiobis-(3-methyl-6-tert.butylphenol). The compsns. are easily applied into the hollow spaces present in the vables. After application they fill =95% of the free space in the cables and thus prevent any water entering the cable. The gelled prods. do not affect the flexibility of the cable and are easily removed e.g. for cable splicing to be carried out. The fillings have excellent electrical properties such as low loss factor and low relative dielectric constant.