Hoechst Aktiengesellschaft

Andree Henze

Karsten Blatter

Gordon Calundann

Peter Simon

To prepare nitrogen-containing polycondensates, a starting substance which still contains reactive end groups is dispersed in a high-boiling inert solvent, preferably in the presence of a dispersing auxiliary, low molecular weight by-products are distilled off at elevated temperature, the batch is cooled and the dispersed polycondensate is isolated. To prepare the starting substance, a mixture of at least two monomers which react with one another is heated up to a constant reaction temperature, a melt being formed at least in part, but initially no homogeneous melt occurring. The reaction is continued until a homogeneous melt is present. The precondensate formed is then dispersed in the high-boiling inert solvent and the condensation reaction is brought to completion.

Process for the preparation of high molecular weight polycondensates

A process is described for the preparation of polyesters by polycondensation of dicarboxylic acid-diol precondensates (oligomers) at elevated temperature in a liquid heat transfer medium in the presence of customary polycondensation catalysts and, if appropriate, cocondensable modifying agents, wherein the liquid heat transfer medium is inert and free of aromatic structural groups and has a boiling point in the range from 200.degree. to 320.degree. C., wherein the weight ratio of dicarboxylic acid-diol precondensate (oligomers) employed to liquid heat transfer medium is in the range from 20:80 to 80:20 and wherein the polycondensation is carried out in the reaction mixture at 200.degree. to 320.degree. C. in the presence of a dispersion stabilizer. Furthermore, the polyesters and copolyester which can be prepared by the process and their use are described.

Process for the preparation of polyesters and copolyesters, the products

To prepare nitrogen-containing aromatic polymers, for example polyamides, polyimides and polybenzimidazoles, polyvalent aromatic carboxylic acids and aromatic diamines and/or aminocarboxylic acids or reactive derivatives thereof are reacted in a high-boiling inert solvent with the addition of a heat-stable dispersing auxiliary, and volatile by-products formed in this reaction are distilled off. When the reaction has ended, the batch is cooled and the polymer formed is filtered off.

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Hofheim, Germany

Andree Henze