Production and use of polyester carbonates
AssigneeBayer Aktiengesellschaft
InventorsSilke Kratschmer, Lothar Bunzel, Wolfgang Alewelt, Renate Wilms
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Abstract
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.
Claims12
A transesterification process for producing polyester comprising in a first stage heating to a temperature of 200 to 290° C., in an inert gas atmosphere for about 30 to 300 minutes, a first mixture containing at least one dihydroxy compound and at least one diaryl carbonate to form an oligocondensate, and in a second stage adding to said oligocondensate at least one dicarboxylic acid to form a second mixture therewith and heating the second mixture for 60 to 200 minutes at a temperature not higher than 290° C. in the presence of a quaternary onium compound as catalyst to form polyester carbonate, and distilling-off under reduced pressure the hydroxyaryl formed throughout said process.
A transesterification process for producing polyester comprising in a first stage heating to a temperature of 200 to 290° C., in an inert gas atmosphere for about 30 to 300 minutes, a first mixture containing at least one dihydroxy compound and at least one diaryl carbonate to form an oligocondensate, and in a second stage adding to said oligocondensate at least one dicarboxylic acid to form a second mixture therewith and heating the second mixture for 60 to 200 minutes at a temperature not higher than 290° C. in the presence of a tetraphenylphosphonium phenolate as catalyst to form polyester carbonate, and distilling-off under reduced pressure the hydroxyaryl formed throughout said process.
Polyester carbonate characterized in having a color number of <0.2 and a characteristic number, Q, lower than 1.3 wherein Q = x + [ 10 ( 5 y + 4 z ] 2 x
- and x is the wt. % of esterified acid in the polyester carbonate, y is the wt. % of free COOH in the polyester carbonate and z is the amount, in wt. % of anhydride structural units in the polyester carbonate.
Dependencies are inferred from the claim text.