Flame retardant dielectric compsn. - comprising mixt. of poly:chlorobenzene(s) and poly:alkyl bi- or terphenyl(s), for transformers

摘要

Parent patent described flame resistant dielectric compsns. comprising (a) a polychlorobenzene (PCB) fraction contg. a PCB with >=3 Cl atoms and o-dichlorobenzene (o-DCB); and (b) a hydrocarbon oil comprising >=u hydrocarbon such as mono- or polyalkylbiphenyls, mono- or polyalkylterphenyls and di- or terphenyls which are at least partly hydrogenated. In the patent of addn. o-DCB is replaced by m- and/or p-DCB opt. mixed with o-DCB. More specifically the compsn. comprises: (A) 75-90% of a mixt. of (i) 75-95wt. % >=1 PCB from tri- and tetra-chlorobenzene and (ii) 25-5wt.% m- and/or p-DCB opt. mixed with o-DCB, and (B) 25-10% of (b) in parent patent, the alkyl having 1-5C. Compsn. is used as an insulator in e.g. capacitors, and transformers. Compsn. stays liq. in use even at low temps. (-25 degrees C), is non-flammable, has low viscosity (15 cp at 60 degrees C); has excellent dielectric props. and is biodegradable.