Verfahren zum Herstellen eines Diaphragmas, insbesondere eines Separators für elektrische Akkumulatoren

摘要

993,851. Permeable diaphragm material. BRITISH FIBRAK SEPARATOR CO. Ltd., M. P. LATHAM, and A. HARDY. Oct. 6, 1962 [Oct. 9, 1961], No. 36211/61. Addition to 954,296. Heading B2E. A permeable diaphragm material comprises a corrugated porous base material and a layer of sintered thermoplastic powder bonded to the corrugated material by a continuous bond of sintered thermoplastic powder. The material may constitute an electric battery separator wherein the corrugated sheet is a fibrous sheet comprising cellulose fibres with up to 10% glass fibres impregnated with an acid-resisting resin, e.g. a water-soluble phenolic resin or a polyvinyl chloride latex. The sintered powder, e.g. polyvinyl chloride, may have an average particle diameter of about 10 microns, and the bond may be a sintered mixture of thermoplastic powders having an average particle diameter of from ¢-1 micron, and about 10 microns. The face of the sintered layer may have pores of predetermined size constituted by the interstices of a continuous lace-like network of thermoplastic extending over the face, the network comprising abutting finely divided particles of the thermoplastic sintered together at their points of contact and adhering to the face. The non-coated face of the corrugated base material may have pores of predetermined size constituted by the interstices of a continuous lace-like network of thermoplastic extending over the face, the network comprising abutting finely divided particles of the thermoplastic sintered together at their points of contact and adhering to the base material. The material may be produced by impregnating a fibrous sheet with acid-resisting resin, corrugating and curing or partially curing the material, coating a face of the material with a mixture of finely divided particles of a thermoplastic including at least two constituents of different average particle size such that the particles penetrate into the corrugated material, covering the coating with a layer of finely divided particles of thermoplastic having an average particle size substantially the same as the larger of the said constituents, and then sintering the thermoplastic. Finely divided particles of a thermoplastic may be applied to the face of the sintered layer, and to the non-coated face of the base material, so as to form a layer of abutting particles, the particles being then sintered together at their points of contact to form a continuous lace-like network having interstices which constitute pores of regulated size. The material may be passed under a finishing roller to produce a ribbed or flat surface as desired. Specification 843,452 also is referred to.