GB222167A - Improvements in the manufacture of sound records - Google Patents

Abstract

222,167. Dreyfus, C. May 18, 1923. Blanks.-Gramophone and like record blanks are made from a composition comprising rosin and cellulose acetate or other organic acid esters of cellulose or ethers of cellulose; or the rosin may be incorporated with a mixture of such cellulose derivatives, with or without the addition of solvents, plasticizing agents, pigments, filling- materials, stabilizers or neutralizers. Many suitable additional ingredients of these kinds are mentioned. The amalgamation of the rosin with the cellulose derivatives mav be made in solution, preferably using a solvent boiling below 150‹ C., or the ingredients may be mixed together under heat and pressure, or in any other way. A composition in which proportions of the ingredients are specified by way of example comprises rosin, cellulose acetate, and paratoluene sulphonamide, or paratoluene sulphonanilide, or a liquid high-boiling alkylated xylene, toluene, or benzene sulphonamide derivative such as described in Specifications 132,283, 133,353, and 154,334, [all in Class 2 (ii), Cellulose, &c.]. These substances are melted and mixed together, and after the mass has cooled it is powdered and mixed with filling materials, and with dyes or pigments if desired. The mixture is then worked into sheets on hot malaxating rolls, the sheets being afterwards cut into blanks on which sound impressions are made by a matrix. The composition may be pressed into blocks, which are afterwards cut into blanks, or the composition or solution may be used in making laminated records by coating paper &c. sheets which are united by heat and pressure.