GB1378751A - Electric insulators - Google Patents

Abstract

1378751 Insulators BRITISH INSULATED CALLENDER'S CABLES Ltd and BRITISH INSULATED CALLENDERS CONSTRUCTION CO Ltd 23 March 1972 [24 March 1971] 7697/71 Heading H2C An insulator, e.g. a section insulator, comprises a body having at least one surface (the running surface), formed by a composition comprising the cured reaction product of a cycloaliphatic epoxy resin, an acidic hardener, an accelerator, and dispersed in the product a mineral filler and a low-friction fluorocarbon polymer in specified proportions, the insulator being reinforced with glass fibres or other fibres of high tensile strength. Preferably the hardener is dicarboxylic or polycarboxylic acid or an anhydride thereof, possibly including a small proportion of, e.g. polyazelaic polyanhydride, the accelerator is of the amine or polyol type, or stannous octoate, the filler is of quartz or silica flour, calcite, gibbsite, bauxite, insulating grade clays or periclase, with a particle size preferably not greater than 50 micrometers; the fluorocarbon polymer is of fine dispersion grade P.T.F.E. A preferred composition for the material is given. Insulators may be made wholly of this material with a glass fibre rod insert and compression-jointed metal endfittings, possibly pinned in place (Figs. 1-3 and 6-8, not shown), to avoid flexure, a web of resinbonded fibre glass (5) may be glued to the rod (Fig. 4, not shown). If the material is vacuumcast on the glass fibre, the surface may be "resin-rich"-this is removed by abrading. A conventional cycloaliphatic resin may be used for part of the rod (7) (Fig. 5, not shown).