Abstract: The invention relates to a dielectric composition having improved gas absorption for electrical devices which comprises from 99% to 70% by weight of a mineral oil and from 1% to 30% by weight of at least one polyarylalkane composition.

Abstract: The invention relates to a crosslinkable impregnating dielectric composition comprising a polydiene polyol, a polyisocyanate and a chemically inert liquid filler, (an insulating liquid) characterized in that a sufficient amount of the said liquid filler is used in order to maintain a viscosity of less than 50 mPa s at the impregnation temperature for a period at least equal to 1 day and in order to obtain a tans at 20° C. and at 50 Hz, after complete crosslinking, of less than 0.02. The invention also relates to a process for preparing the said composition.

Abstract: The invention relates To a process for the impregnation of electrical capacitors which includes performing the impregnation of the coil winding with a dielectric fluid, eliminating the excess of the dielectric fluid, filling the casing containing the impregnated coil winding with a gelable composition and the dielectric fluid for impregnating the coil winding and gelling the gelable composition.

Abstract: The present invention relates to the use of insulating fluids, selected from the group consisting of aliphatic esters, alkylbenzenes, crosslinkable compositions comprising at least one polydiene polyol, at least one polyisocyanate and at least one chemically inert liquid charge, for the impregnation of the wound coils of self-healing capacitors.

Abstract: The invention relates to a process for impregnation of electrical capacitors which consists in performing the impregnation of the coil winding with a dielectric fluid and then eliminating the excess of the said fluid and in filling the casing containing the said impregnated coil winding with a gelable composition including the said dielectric fluid for impregnation of coil winding.

Abstract: The invention relates to a dielectric composition including at least one polyarylalkane oligomer of formula: ##STR1## in which n.sub.1 and n.sub.2 =0, 1 or 2, with the proviso that n.sub.1 +n.sub.2 =1 or 2, x=0, 1, 2, 3, 4, 5 or 6 and that the said composition has, in particular, a breakdown voltage increasing with the temperature.

Abstract: Novel dielectric liquids for such electrical components as transformers, capacitors and cables, especially adopted for low temperature applications, comprise immixtures of benzyltoluene, (methylbenzyl)toluene, benzylxylene and (methylbenzyl)xylene, and optionally include the benzyl or methylbenzyl derivatives thereof; these immixtures are facilely prepared by chlorinating a mixture of xylene and toluene and then adding a catalytically effective amount of a Friedel-Crafts catalyst to the medium of chlorination.

Abstract: Novel dielectric liquids for such electrical components as transformers, capacitors and cables, especially adopted for low temperature applications, comprise a mixture of benzyltoluene and (methylbenzyl)xylene isomers, notably a mixture of benzyltoluene/dibenzyltoluene isomers with (methylbenzyl)xylene/di(methylbenzyl)xylene isomers.

Abstract: Benzyltoluene/benzylxylene admixtures, easily prepared via Friedel-Crafts condensation of benzyl chloride with a mixture of toluene and xylene, are useful dielectric oils exhibiting improved rigidity and are well suited for inclusion in voltage transformers, capacitors, electrical cables, and the like.

Abstract: Novel dielectric compositions, well adapted for low temperature applications, include admixture of benzyltoluene, benzylbenzene and the higher homologs thereof, and optionally contain triphenylmethane, ditolylphenylmethane, tolyldiphenylmethane and the higher homologs thereof; the subject novel compositions are prepared by chlorinating a mixture of toluene and benzene and then treating the product of reaction with an inorganic halide.

Abstract: Dielectric liquids are prepared by (a) Friedel-Crafts condensing at least one aromatic halide with at least one aromatic compound in the presence of a catalytically effective amount of ferric chloride, and thereafter deliberately avoiding any downstream destruction/neutralization and/or washing of such ferric chloride catalyst, (b) optionally, removing unreacted reactants from the medium of reaction, and (c) recovering from such medium of reaction a purified dielectric liquid; the subject process is thus environmentally improved by avoiding the generation of aqueous solutions containing contaminating amounts of objectionable organic compounds.

Abstract: Novel dielectrically improved liquid compositions include at least one electrical insulating oil (A), e.g., benzyltoluene or oligomers thereof, and at least one aldehyde (B) containing at least six carbon atoms, or a functionally substituted such aldehyde, e.g., 3-ethoxy-4-hydroxybenzaldehyde.