GB928312A - Process for the polymerisation of lactams - Google Patents

Abstract

A process for the production of polyamides comprises mixing a monomeric lactam having at least six carbon atoms in the ring with a compound of the formula LiAlRn(OR1)4-n, where n is an integer of from one to four inclusive, R is H or alkyl and R1 being alkyl, and maintaining the mixture at a temperature above its melting point until a solid product is produced. Lactam polymerization accelerators, e.g. organic p isocyanates, carbodiimides or acyl halides may also be present in the reaction mixture. Specified lactams are S -caprolactam, enantholactam, capryllactam, dodecanolactam, a -methyl-S -caprolactam, a ,d -dimethylcaprolactam and b -phenyl-S -caprolactam. Specified lithium aluminium compounds are lithium aluminium hydride, lithium-tri-t-butoxy alumino hydride, lithium-tri-t-amyloxy alumino hydride, lithium diethoxy alumino hydride, lithium di-isopropoxy alumino dihydride, lithium aluminium tetraethyl, lithium dimethyl aluminodihydride, lithium aluminium tetra-n-butyl, lithium aluminium n-butyl tri-isobutyl, lithium aluminium tetra-n-hexyl, lithium aluminium tetra-n-octyl, lithium aluminium tetra-n-decyl and lithium aluminium-n-propyl triethyl. In the examples, S -caprolactam is polymerized in the presence of:-(1) lithium aluminium hydride; (2) lithium aluminium n-butyl tri-isobutyl; (3) lithium aluminium tetra-n-decyl and (4) lithium tri-t-butoxy alumino hydride. Inert pigments and fillers, e.g. finely divided metals, glass fibres or graphite may be present in the reaction mixture. Specification 924,453 is referred to.