GB691278A - Linear polyamides - Google Patents

Abstract

Polyamides resistant to degradation on exposure to daylight are obtained by reacting diamines with dicarboxylic acids having the general formula <FORM:0691278/IV (a)/1> where x is an integer from 3-10. Examples specified are diphenoxy-propane (butane, pentane, hexane or decane)-4 : 41-dicarboxylic acids. Other dicarboxylic acids may be mixed in minor proportions with these acids and reacted simultaneously with the diamines, lists of which are given in the Specification. Some or all of the reactants may be used in the form of amide forming derivatives. If desired, a proportion of a monoaminocarboxylic acid, e.g. caprolatam, may be included, e.g. as described in Specification 495,790. The polyamide forming reaction is carried out under conventional conditions, e.g. at temperatures of 200-300 DEG C. and in presence of solvents, e.g. phenol, and catalysts, e.g. phosphoric acid. Filaments are formed from the polyamides by melt extrusion and may be drawn on rollers. In examples: (1) 80 parts of the salt formed from hexamethylene diamine and diphenoxybutane-4 : 41-dicarboxylic acid, 10 parts phenol, and 0.04 parts phosphoric acid are heated at 220 DEG C. for 2 hours in an evacuated nitrogen purged vessel. The vessel is opened and heated for another hour while a slow stream of oxygen-free nitrogen is passed through the melt. The reactants in the other examples are (2) diphenoxypropane - 4 : 41 - dicarboxylic acid; (3) diphenoxyhexane-4 : 41-dicarboxylic acid. In (4) and (5) the ether esters of the acids are employed; (6) the product of (1) is dried for 20 hours at 160 DEG C., moulded into a rod of 1 inch diameter at a p temperature of 265 DEG C. and a pressure of 5600-6000 p.s.i., and extruded to form filaments as described in Specification 527,532. Specification 487,734 also is referred to.