摘要:
Process for the preparation of copolyamides from adipic acid, terephthalic acid and hexamethylene diamine containing 25-48% by weight of units of hexamethylene terephthalamide, by precondensing the monomers at a temperature of at least 250.degree. C. and a pressure of at least 35 bar and completing the polycondensation in the usual manner.
摘要:
A process for the production of polyamides by the polycondensation of aqueous solutions of salts of diamines and dicarboxylic acids by continuously introducing the aqueous salt solution into a precondensate melt under atmospheric pressure and simultaneously distilling off the water and maintaining the temperature of the melt at a minimum temperature of 180.degree. C.
摘要:
A transesterification process for producing polyester is disclosed. In a first stage of the process there is heated, in an inert gas atmosphere, a first mixture containing at least one dihydroxy compound and at least one diaryl carbonate to form an oligocondensate. In a second stage there is added to the oligocondensate at least one dicarboxylic acid to form a second mixture. The second mixture is heated to a temperature not higher than 290° C. in the presence of a quaternary onium compound as catalyst to form polyester carbonate. Hydroxyaryl formed throughout the process is distilled-off under reduced pressure.
摘要:
An improvement to the transesterification process for the production of aromatic polycarbonates is disclosed. Into the melt which contains diphenols, carbonic acid diaryl esters and optionally branching agents and at temperatures of 130.degree. C. to 400.degree. C. and in the presence of catalysts there is mixed or passing thereover inert gas in a quantity of at least 0.5 Nm3 per kg of polycarbonate melt.
摘要:
A process for the production of polycarbonates is disclosed. Accordingly, oligocarbonate in the melt is passed through a heated tube and inert gas is simultaneously introduced by injecting to the melt.
摘要:
This invention relates to a simplified process for the preparation of polyarylene sulphides with improved product quality from alkali metal sulphides and dihalogenated aromatic compounds, in which the alkali metal sulphides are prepared and reacted in situ.
摘要:
The invention relates to a process for purifying and isolating polyarylene sulphides. In this process polyarylene sulphides are obtained with a particularly low electrolyte content.
摘要:
This invention relates to optionally branched polyarylene sulphides and a process for the production thereof in a polar solvent, from 0.2 to 100 mole %, based on the aromatic dihalogen compounds, of an amino acid being added to the reaction mixture.
摘要:
The present invention provides a two-stage process for the production of polyester carbonates with aliphatic dicarboxylic acids, the polyester carbonates obtained thereby, a process for the production of extrudates and molded articles from the polyester carbonates, and the extrudates and molded articles obtained thereby.