GB622201A - - Google Patents

Abstract

622,201. Condensers ; insulation. BALSBAUGH, J. C. Oct. 5, 1945, No. 25934. Drawings to Specification. [Classes 36 and 37] [Also in Group VIII] A dielectric material for a condenser is produced by assembling a plurality of layers of Alsifilm in face-to-face relationship and compressing the layers into a substantially homogeneous laminated structure. Alsifilm is formed from a gel of purified white California bentonite, which, after drying, is treated with a solution of a salt of a polyvalent cation and an organic acid, e.g. ethylene diamine diacrylate in water. The salt referred to above may be polymerizable to form a dielectric resin, in which case the treated film is dried at a temperature sufficiently low and/or for a time sufficiently short to avoid substantial polymerization. Electrode layers coated with a suitable resin, e.g. zirconyl methacrylate, are then assembled with a number of Alsifilm layers between them, and the whole subjected to a steadily increasing pressure, e.g. up to 1000 lb. per square inch, and to a temperature of 150‹ to 250‹ C., until the Alsifilm is polymerized to form an integral structure. Alternatively, the Alsifilm is cured before assembly, in which case each surface of the electrodes and the Alsifilm is brushed with a lacquer or varnish, e.g. of polyvinyl carbazole and terphenyl dissolved in toluene, the layers assembled as before, and the whole subjected to heat and pressure. In a modification, layers of Alsifilm, either cured or uncured, may be coated with a liquid dielectric, e.g. hydrocarbon transformer oil, and mechanically clamped tightly together between electrodes in a bath of the liquid dielectric. Specifications 573,759, [Group VIII], and 613,521 are referred to.