| 摘要 |
Solutions of linear aromatic poly(imideamide)s which are, on the one hand, clear at room temperature (23 DEG C) and stable in storage at the same temperature and, on the other hand, are suitable for producing especially films or varnishes exhibiting little colour. More precisely, these solutions consist: a) of gamma -butyrolactone as solvent and b) of a particular poly(imideamide) which is prepared by reaction of an aromatic diisocyanate, a monoanhydride of a tricarboxylic acid and optionally of an aromatic diacid, while taking care, on the one hand, to use 2,4-diisocyanatotoluene and/or 2,6- diisocyanatotoluene as diisocyanate and, on the other hand, to conduct the polycondensation in the presence of a chain limiting agent consisting of benzoic acid or phthalic anhydride. The concentration of the poly(imideamide) in the gamma -butyrolactone, expressed as weight of polymer relative to the total of polymer plus solvent, is between 5 and 40%. |
