GB835920A - Improvements in or relating to synthetic linear polymers - Google Patents

Abstract

Process for the continuous manufacture of high molecular weight synthetic linear polyamides containing finely-divided pigments by continuous polymerization in which the starting materials are constantly admitted to the hot reaction vessel, and the finished polymer removed therefrom, comprising adding at any stage during the course of the polymerization, a fluid dispersion of said pigment, which is injected by means of a flexible chamber pump operated synchronously with the feeding machinery controlling the admission of the starting materials, the resultant polymer being extruded.ALSO:In a continuous process for the manufacture of high molecular weight synthetic linear polymers in which the starting materials are continuously admitted to the hot reaction vessel and the finished polymer removed therefrom, a fluid dispersion of a finely-divided piment is injected at any stage of the polymerization by means of a flexible chamber pump operated synchronously with the feeding machinery controlling the addition of the starting materials, the resultant polymer being extruded. Specified polymers are polyurethanes, polytriazoles, polyureas, polyesters and polyamides. Pigments specified are ultramarine, barium sulphate, lead chromate, titanium dioxide, carbon black and copper phthalocyanin. The dispersions may be in water, an omega lactam, an aqueous omega lactam or in a polyamide and may contain dispersing agents, e.g. cetyl pyridinium bromide, ethylene oxide modified sorbitan monooleate, a cetyl alcoholethylene oxide reaction product, sodium hexametaphosphate, sodium pyrophosphate or ammonium oleate. The example describes a polymerization of e -caprolactam using acetic acid as viscosity stabilizer in which an aqueous dispersion of finely-divided titanium dioxide is supplied to the polymerization vessel, the product being extruded in the form of filaments.