METHOD OF REGULATING THE POLYMERIZATION RATE IN THE ANIONIC POLYMERIZATION OF LACTAMS

1276339 Anionic lactam polymerization INVENTA AG FUR FORSCHUNG UND PATENTVERWERTUNG 8 Oct 1969 [9 Oct 1968] 49399/69 Heading C3R The anionic polymerization of lactams with more than 6 ring members is effected using an alkaline catalyst and a combination of cocatalysts one being a "brief activity" co-catalyst (defined by reference to pot-life of a specified polymerization system) and the other being a polycarbodiimide containing at least 3 units where R is C 1-4 alkyl. The latter are those whose use as co-catalysts is the subject of Specification 1,108,721 while the former are exemplified by acetyl lactams, acylating agents e.g. acid chlorides and anhydrides, cyanamides, isocyanates, ketenes and oxazolidinedione derivatives e.g. 2,3-dioxo-2,3,6,6,7,8-hexahydro-oxazolo-[3,2,α)-azepine. Specified alkaline catalysts are lactam-metal compounds which may be formed in situ e.g. from metallic sodium, Grignard compounds or alkali hydrides. The proportions of the co-catalysts may be adjusted to suit the dimensions of the application. Specified lactams are caprolactam, laurolactam and mixtures thereof. Fillers, plasticizers, blowing agents and inorganic or organic pigments may be present during polymerization e.g. graphite, carbon black, MoS 2 , glass fibres, wire gauze or styrene, acrylic, polyester or polyamide resins.