530374-A is referenced by 3 patents.
530,374. Impregnating-compositions for electric insulation; electric cables. CALLENDER'S CABLE & CONSTRUCTION CO.. Ltd., HILL, H., and BECKINSALE, S. May 6, 1939, No. 13617. [Class 140] [Also in Group XXXVI] Fibrous material, e.g. paper or cloth, is impregnated by treatment with (a) an oleaginous liquid vehicle and diluent, (b) a body consisting of or containing free organic acid and (c) a base which reacts with the acid within the material to form a water-insoluble soap. The oleaginous liquid is miscible with or a solvent for the acidic bodies and free from water, for example, petroleum oils, or mixtures thereof with petroleum products, coal tar products, natural bitumens or synthetic resins. Rosin oil may function both as acidic body and oleaginous liquid vehicle. The basic substance may be calcium hydroxide or calcium, magnesium, zinc or aluminium oxides.; The acidic body may be a higher fatty acid, e.g. stearic, palmitic or oleic acids, a natural resin such as rosin, or a destructive distillation product of organic material, e.g. pine tar, stockholm tar, rosin pitch and rosin oil. Coal tars, coal tar pitches and petroleum residual pitches may be added. Either the acidic or the basic component may be incorporated in the fibrous material prior to treatment with the remaining components. For a cable dielectric, paper may be loaded with hydrated lime during manufacture or applied in powder form whilst applying the paper to the conductor. After drying, e.g., at 140 C. the hot cable core is immersed in a cold mixture of rosin oil and thin transformer oil thinned if desired with naphtha or a chlorinated solvent.; For cable sheaths an aqueous suspension of slaked lime is applied and the paper or fabric and quicklime is dusted on the wetted material which is then impregnated with a mixture of blown asphalt, rosin, oleic acid and transformer oil. Alternatively a mixture of rosin oil, lime, calcium hydroxide and transformer oil is used for impregnating immediately after mixing. Embossed paper, e.g. of the kind described in Specification 352,533 may be used as the fibrous material.