Rhone-Poulenc Industries

Atochem

Elf Atochem S.a.

Atofina

Pierre Jay

Noelle Berger

Raymond Commandeur

Ghislain Schwachhofer

Jacques Kervennal

No&euml;lle Berger

Pierre Bonhomme

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&deg; 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.

Crosslinkable dielectric composition

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.

Impregnating compounds for self-healing capacitors

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.

Dielectrics comprising methyl/benzyl derivatives of diphenylmethane

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.

Dielectric compositions comprising benzyltoluene/(Methylbenzyl) xylene

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.

Benzyltoluenes/benzylxylenes dielectric compositions

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.

Low temperature, polyphenylmethane-based dielectric compositions

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.

Synthesis of dielectric liquids by improved Friedel-Crafts condensation

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.

Dielectric liquid compositions containing hydroxybenzaldehyde

Liquid, non-flammable dielectric compositions especially adapted as insulators/coolants for transformers are comprised of [1] a mixture of polychlorobenzenes, including a major amount of an at least trichlorinated benzene and a minor amount of ortho-dichlorobenzene, and [2] an alkylaromatic hydrocarbon or a partially hydrogenated bi- or terphenyl.

Dielectric compositions comprising mixtures of polychlorinated benzenes

Liquid dielectric compositions useful as electrical insulators are comprised of a mixture of a mixed phthalate of isobutyl alcohol and a branched higher alkanol of a diisobutyl phthalate and/or a phthalate of a branched higher alkanol, and wherein the alkyl groups of the constituents contain from 5 to 18 carbon atoms.

Phthalate mixtures useful as liquid dielectrics

Liquid, non-flammable dielectric compositions especially adapted as insulators/coolants for transformers are comprised of [1] a polychlorobenzene and [2] an alkylaromatic hydrocarbon.

Dielectric compositions comprising polychlorobenzene-alkyl terphenyl

Dielectric compositions comprising benzyl esters of .alpha.-branched chain alkyl-substituted saturated monocarboxylic acids having improved thermal and chemical stability for extended periods of operation under varying conditions are provided.

Dielectric compositions containing benzyl esters

Liquid dielectric compositions useful as electrical insulators are comprised of [1] a liquid dielectric component of known type, in combination with [2] at least one member selected from the group consisting of monocyanophenoxybenzene, monocyanodiphenyl and monocyanoterphenyl.

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Saint-Didier Au Mont D'Or, France

Pierre Jay