| abstract |
A transparent polyamide containing terephthalic acid radicals or radicals of the mixture of terephthalic and isophthalic acids and a cycloaliphatic diamine radical and having the chain formations: <IMAGE> +TR <IMAGE> and <IMAGE> +TR <IMAGE> in which: y1+y2 is between 10 and 200 with y1/(y1+y2)>0.5; m, p, m' and p' are whole numbers equal to or greater than zero, such that: <IMAGE> is between 0.5 and 10, taken statistically over the marcomolecule; Z and Z' are the same or different and are either a polymethylene segment -(CH2)-n where n is a whole number equal to or greater than 6 or a sequence containing an amide resulting from condensation of an aliphatic diamine containing at least 6 carbon atoms between the amine functions and an aliphatic dicarboxylic acid containing at least 4 carbon atoms between the acid functions; A and B are the same or different and represent hydrogen or a methyl, ethyl, or isopropyl radical; X and Y are the same or different and represent hydrogen or a methyl radical; and q is a whole number between 0 to 6. The process of making such polyamide comprises a first stage wherein terephthalic acid or a mixture of terephthalic and isophthalic acids containing more than 50 mol. % terephthalic acid are reacted with a lactam followed by a second stage where the oligomeric diacid obtained is reacted with a cycloaliphatic diamine. |