Patent GB-541592-A (GB)
Title: Improvements in or relating to the production of artificial filaments, films and other articles from organic polymerisation products
IPC: D01F6/60
Filed: 1940-05-31
Abstract: 541,592. Artificial filaments, films &c. ; resinous condensation products. DREYFUS, H., MONCRIEFF, R. W., and SAMMONS, C. W. May 31, 1940, No. 9551. [Classes 2 (ii) and 2 (iii)] Artificial filaments, yarns, films, foils, and other shaped or moulded articles are obtained by shaping or moulding in the fused condition a solution comprising a filament-or film-forming polymer in formic acid and having such a composition that it is a solid solution at ordinary temperatures. The polymer may be a synthetic linear condensation polymer, e.g. a polyamide. The polymer may be obtained by condensing a diamine with a dicarboxylic acid or a dihalide or diester of a dicarboxylic acid. It may be obtained by condensing an aminocarboxylic acid with itself or with another similar compound. The polymer may be formed by condensation of hexamethylene diamine and adipic acid and it may be formed into a solid solution with formic acid, the solution comprising 72 per cent. of polyamide and 28 per cent. of formic acid. The solid solution becomes liquid on heating. Such a composition may be formed from a more dilute solution by heating and evaporating part of the formic acid. Artificial filaments may be obtained by extruding the molten composition under the pressure of an inert gas, or liquid, and the extruded materials may be received in an inert atmosphere contained in an enclosed chamber. The extruded materials may be received, preferably after a short passage through a hot gaseous medium, in a liquid setting medium, e.g. water, an aqueous solution of caustic soda, or sodium formate, or an organic medium such as acetone. The filaments may be drawn at a speed exceeding the rate of extrusion and they may be further stretched, preferably in presence of water, steam, or other hydroxy-containing compound, after setting. Residual formic acid may be removed by washing. The formic acid may be used together with additions of other solvents such as trichloracetic acid, phenol, or resorcinol, or a low melting point sulphonamide may be incorporated in the solution. Effect materials, such as titanium dioxide, pigments, or dyestuffs may be added. Instead of polyamides, other fibre- or filmforming materials may be used. The fused composition may be moulded by injection moulding devices. Staple fibre may be obtained from the continuous filaments, e.g. by cutting. The films may be used for wrapping purposes or for inter-layers in splinterless glass manufacture. In an example, hexamethylene diammonium adipate, phenol, and adipic acid, are heated at 190‹ C. for several hours in an atmosphere of nitrogen to form a high viscosity polymer. The product is dissolved in formic acid and the solution is poured into water. The precipitated polymer is washed with hot water and acetone. It is dissolved in formic acid and the solution is concentrated by heating at 75‹ C. until the mass becomes solid at that temperature. The mass is then fused under nitrogen and extruded through a heated nozzle into a chamber containing nitrogen. Specifications 529,510, 540,967 and 541,238 are referred to.