GB474712A - Improvements in or relating to electrical conductors and insulating compositions therefor - Google Patents

Abstract

Electric conductors are insulated with a transparent and flame-proof composition containing 100 parts of cellulose derivative admixed with at least 90 parts of plasticizer comprising an alkyl or dialkyl phthalate and a mixture of phenyl phosphates, at least 10 parts of phthalate being present in order to ensure transparency in the composition. Cellulose acetate, formate, propionate, or butyrate, or ethyl, methyl, or benzyl cellulose, may be used as cellulose derivative in the composition. Mixtures of triphenyl and tricresyl phosphates together with dimethyl or diethyl phthalate may be used as plasticizer. The alkyl phthalate serves as high boiling solvent as well as plasticizer. Preferably the composition is mixed with a low boiling solvent such as acetone and applied to the conductors as a lacquer. The coating bath may be at room temperature. After leaving the coating bath, the conductor, e.g. a wire, may be passed through dies or other means for regulating the thickness of the coating. It may then be passed through an oven, the temperature of which should not be below 120 DEG F. If desired the coating may be applied to a conductor already covered with a textile serving. The transparent coating enables identification colourings or tracer threads of the textile serving to be viewed therethrough. The Specification as open to inspection under Sect. 91 refers also to the production of opaque coatings by reducing the proportion of dimethyl phthalate or by reducing the temperature of drying. This subject-matter does not appear in the Specification as accepted.