maybe (precursor to?) this form of varnish
formatting link
This invention relates to polymeric insulation compositions which are crosslinked to produce heat resistant and flame resistant products useful for coating wire and cable products. More particularly, the invention relates to crosslinkable flame retardant ethylene-vinyl ester and ethylenealkyl acrylate copolymer insulation compositions which do not tarnish the surface of copper conductors upon curing. / THE PROCESSING ADDITIVE While any known processing agent can be employed, fatty acids or fatty acid derivatives, polymeric processing resins and hydrocarbon oils, or combinations thereof, are most generally used. The fatty acid derivatives can include metal soaps, esters, ester-soaps, amides, and the like. The term fatty acid as employed herein, refers to aliphatic carboxylic acids having from 8 to 22 carbon atoms. While these acids are usually derived from natural sources, they can also be synthetically produced. The fatty acids can be branched or straight-chain, saturated or unsaturated and they may consist of a single acid, or as is more commonly the case, a mixture of acids within the specified carbon content range. Illustrative fatty acids include caproic acid, caprylic acid, capric acid, lauric acid, myristic acid, myristoleic acid, palmitic acid, palmitoleic acid, stearic acid, isostearic acid, oleic acid, linoleic acid, eleostearic acid, behenic acid, erucic acid and the like. Useful fatty acid mixtures are obtained from triglycerides present in natural fats and oils including coconut oil, cottonseed oil, linseed oil, palm oil, soy oil, tall oil, safflower oil, corn oil, rapeseed oil, tallow or the like.