GB914022A - Production of a finely divided polymer - Google Patents

Abstract

S -caprolactam is polymerized by heating at 80 DEG to 125 DEG C. under substantially anhydrous conditions in the presence of (a) a catalytic amount of an alkali or alkaline earth metal including magnesium, or of a compound of such a metal or of an organo-metallic compound of aluminium or zinc which acts as an anionic polymerization catalyst and (b) a compound containing at least one tertiary nitrogen atom, one group linked to the nitrogen atom being a carbonyl, thiocarbonyl, sulphonyl, phosphinyl or thiophosphinyl group and a second being a carbonyl, thiocarbonyl, sulphonyl, phosphinyl, thiophosphinyl or nitroso group. In a modification of the process there is also present a primary or secondary amine. Specified catalysts include sodium, potassium, lithium, calcium, strontium and barium and hydrides, borohydrides, oxides, hydroxides, amides and carbonates thereof, lithium butyl, di-iso-butyl aluminium chloride and phenyl magnesium bromide. Specified compounds containing tertiary nitrogen atoms include N-substituted imides, e.g. N-acetyl-2-pyrrolidone; N-substituted cyclic imides of dicarboxylic acids, e.g. N-phenyl-succinimide; N:N-diacyl primary alkyl and aryl amines and N:N-diacyl acyl amides, e.g. N:N-diacetyl methylamine; the N:N1:N11-triphenyl ester of isocyanuric acid; N-acyl sulphonamides and N-acyl sulphonimides, e.g. N-acetyl-N-ethyl-p-toluene sulphonamide; disulphonamides of primary alkyl and aryl amines, e.g. N:N-di (p-toluene sulphonyl) amide; N-nitrosoamides, e.g. N-nitroso-2-pyrrolidone; N-nitrososulphonamides, e.g. N-nitroso-N-methyl benzene sulphonamide and N-(dimethyl phosphinyl)-S -caprolactam. Specified primary and secondary amines include methylamine, n-propylamine, iso-propylamine, n-butylamine, t-butylamine, n-pentylamine, t-amylamine, n-hexylamine, stearylamine, benzylamine, cyclohexylamine, dicyclohexylamine and morpholine. The examples disclose the polymerization of S -caprolactam in the presence of N-acetylcaprolactam and sodium hydride. The products of the process may be admixed with glass fibres, clays, calcium carbonate, titanium dioxide, carbon black, molybdenum disulphide, dyes or metallic powders and used as moulding compositions.