Improved manufacture of stencil sheets for autographic and typewriting duplication purposes

摘要

205,461. Koresca, W. Oct. 11, 1922, [Convention date]. Water paints.-A stencil is prepared from a sheet of Japanese paper coated with a composition including protein and suitable tempering agents such as natural and artificial soft resins, e.g. colophony or coumarone resin, fatty acids, and fatty substances or similar esters of high molecular weight, oils, soaps, waxes, such as wool-fat, hydrocarbons, natural or artificial caoutchouc masses, gutta-percha and balata. If the substance chosen is soluble in a protein-solvent the dissolving is done simultaneously; otherwise, the -substance is added to the protein solution in the form of a colloidal solution, an emulsion or a suspension. Also, in the case of substances insoluble in protein-solvents, a soluble product generated by transformation or conversion of the substance may be added to the solution of protein and, after the formation of the coating, be retransformed into the original substance, e.g. carbonic or sulpho-acids or resins may be introduced in the form of soaps and afterwards transformed into the free fatty acids. When ammonium soaps are used the transformation may be effected by heating. In a preferred form the substance used is an ammonium soap or a mixture of ammonium soaps of different fatty acids and as a coagulating medium formaldehyde is used. Suitable proportions are given for a coating solution comprising a solution of protein, a solution of stearate of ammonium, a solution of oleate of ammonium and water.