Importance

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Abstract

The present invention relates to substantially pure poly(arylene ether), e.g. purities exceeding about 99%, and to a method for making the same. The method which eliminates multiple rinses with a complexing reagent includes removing the catalyst from the polymerization mixture by mixing the polymerization mixture with a complexing reagent and liquid/liquid centrifuging the multiphase mixture. Water is then added to the polymer phase prior to a subsequent liquid/liquid centrifuge process. Once the catalyst has been sufficiently removed, the polymer can be concentrated in a flash vessel (which is not heated) by introducing a heated polymer phase to the vessel at a high pressure and quickly reducing the pressure. The concentrated polymer can then be introduced to an extruder to produce the high purity polymer. Due to the introduction of low molecular weight poly(arylene ether) at the intake zone of the extruder, essentially pure poly(arylene ether) can be isolated by this process. By combining the extruder process with an underwater pelletizer, thus providing extremely rapid cooling of the polymer melt when it exits the extruder and contacts air, much better color and lower amount of black specs in the final product is obtained.

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First Claim