PROCESS FOR THE PRODUCTION OF PIGMENTED POLYAMIDES

1380498 Pigmented anionic polylactams BAYER AG 16 Feb 1972 [17 Feb 1971] 7096/72 Heading C3R A process for producing pigmented polyamides comprises adding (e) an aluminium alcoholate to a mixture of (a) one or more lactams, (b) an alkali or alkaline earth metal lactamate as catalyst, (c) an activator and (d) a pigment or pigment mixture and subjecting the resulting mixture to anionic polymerization. Specified compounds are (a) copro, oenanthic, capylic and lauric lactams; (c) isocyanates, carbodiimide, carbonimides and triazines; (d) ultramarine, TiO 2 , yellow iron oxide and BaSO 4 ; and (e) aluminium methoxide to butoxide, amylate, benzylate and octadecane diolate : (b) may be prepared in situ, e.g. from Na or K formate, Na methylate, K butylate or Na phenolate or from hydrides, oxides or carbonates The aluminium alcoholate is stated to counteract the inhibiting effect of the pigment, reduce the extractable monomer content and result in improved pigment dispersion using little or no wetting agent. The process may be effected continuously or discontinuously to produce granulated for injection moulding or extrusion.