Dynamit Nobel Aktiengesellschaft

Erich Behr

Norbert Vollkommer

Wolfgang Wolfes

A process for the preparation of a thermostable polyester which is insoluble in tetrachloroethane and consists of about 40 to 200 units, said polyester having units of the formula ##STR1## combined with units of the formula ##STR2## wherein Ph is ##STR3## AND BOTH R radicals are methyl on some units and both R radicals are phenyl on the balance of the units, said methyl units comprising 5-30 mole percent of the total R-containing units which comprises heating and condensing in the absence of a catalyst 4,4'-dihydroxytetraphenylmethane having a melting point of at least 295.degree. C together with 2,2-bis-(4-hydroxyphenyl)-propane and terephthalic or isophthalic acid dichloride until there is prepared said polyester which is insoluble in tetrachlorethane.

Thermostable polyester

In a process for the manufacture of a polyimide from a polyamide carboxylic acid solution by cyclodehydration of the polyamide carboxylic acid, the improvement which comprises carrying out said cyclodehydration in the presence of a nitrogen containing compound selected from the group consisting of quinoline, isoquinoline, mono-substituted alkyl pyridines, dialkyl substituted pyridines, mono-substituted alkyl quinolines, dialkyl substituted quinolines, monoaralkyl substituted quinolines, diaralkyl substituted quinolines, monoalkyl substituted isoquinolines, dialkyl substituted isoquinolines, monoaralkyl substituted isoquinolines, diaralkyl substituted isoquinolines and mixtures thereof.

Growing community of inventors

Troisdorf, Germany

Erich Behr