Injection moldable glass clear transparent polyamide

Claim 1

A copolyamide having a glass transition temperature (Tg) of 140°-170° C. consisting essentially of the polymeric condensation product of (a) a diamine of the formula ##STR2## wherein R 1 and R 2 are independently selected from the group consisting of hydrogen and methyl, n is an integer from 0 to 6, and wherein each cyclohexane ring may be partially or wholly substituted with methyl groups; (b) a substantially stoichiometric amount, based on the amount of component (a), of a dicarboxylic acid or acid mixture, consisting of from 50 to 100% of isophthalic acid, from 0 to 50 mol or weight % of terephthalic acid, and from 0 to 15 mol % of other polyamide-forming dicarboxylic acid or acids; and (c) 30 to 40% by weight, based on the total weight of components (a), (b) and (c), of a further polyamide-forming component which is selected from the group consisting of amino lauric acid, laurolactam and aminoundecanoic acid, some of said group may be replaced by a member of the class consisting of aliphatic dicarboxylic acids and aliphatic diamines, stoichiometric mixtures of aliphatic dicarboxylic acids and aliphatic diamines, and blends of said salts and mixtures, said member subject to the conditions that the average number of carbon atoms per amide group or between each pair of amide-forming groups is at least 9, that the minimum number of carbon atoms between the amide-forming groups is at least 6, and that, when component (b) is not 100% isophthalic acid or isophthalic acid/terephthalic acid mixture, the sum of the weights of the other polyamide-forming dicarboxylic acids in (b) and of component (c) must be from 30 to 40% by weight, based on the total weight of components (a), (b) and (c), said product having a melt viscosity of 2000 to 15000 poises at about 300° C.