GB536130A - Improvements in or relating to the moulding of polymeric materials - Google Patents

Abstract

536,130. Moulding polyamides. DU PONT DE NEMOURS & CO., E. I. Sept. 26, 1939, No. 26680. Convention date, Sept. 30, 1938. [Class 2 (iii)] [Also in Group V] Shaped articles are prepared by heating to a temperature above its melting point sufficient to cause ready flow under pressure but insufficient to induce excessive fluidity a composition comprising a crystalline synthetic linear polyamide or polyester-polyamide with or without plasticizers and fillers, forcing the molten composition under pressure into a closed mould, cooling to the solid state within the mould and ejecting the formed article. Articles that may be made include combs, solid toilet ware, electric switch cases, electric insulation, vanity boxes, powder boxes, knobs, handles, buttons, jewellery, rods, tubes, printing rolls, stamping and printing dyes, machine bearings, shoe box toes, shoe heels, shoe counters, hookless fasteners, toys, unbreakable bottles, dentures, mouthpieces for pipes, printing plates, piano keys, billiard balls, ivory substitutes, gaskets and dishes. Suitable polymers include those derived from amino acids (or derivatives such as lactams), or from diamines and dibasic acids with or without the addition of reactants such as hydroxyacids or glycols. Plasticizers include sulphonamides (such as N-alkylated toluene sulphonamides), phenols (such as diphenylolpropane, diamylphenol, tertiary amylphenol) and cyclic ketones (such as camphor). Fillers include talc, kieselguhr, asbestos, mica, or effect materials such as pearl essence. In examples, molten compositions for injection into moulds are prepared by (1) heating a mixture of hexamethylene di-ammonium adipate and mixed toluene sulphonamides ; (2) heating a mixture of hexamethylene diammonium adipate, N- ethyl-o- and -p-toluene sulphonamides and p-tertiary-amylphenol, extruding into cold water grinding and melting ; (3) grinding polyhexamethylene adipamide and heating the powder ; (4) heating a mixture of hexamethylene diammonium adipate and decamethylene diammonium adipate, extruding into cold water, cutting and heating ; (5) heating a mixture of hexamethylenediammonium adipate and diamylphenol, with or without the addition of talc, extruding into cold water, cutting and heating; (6) heating a mixture of adipic acid, ethylene glycol and hexamethylene diammonium adipate, grinding the product and heating.