To provide a method for efficiently and stably manufacturing powders of a low-molecular weight polyphenylene ether while suppressing the polymer loss due to scales, and further to provide a simple manufacturing method that is adaptable to the batch operation suitable for separately producing polyphenylene ethers having a variety of molecular weights, and also to the continuous operation suitable for mass production of polyphenylene ethers having the same molecular weight.
The method of manufacturing polyphenylene ether comprises polymerizing a phenolic compound in the presence of a catalyst and an oxygen-containing gas using at least one good solvent (A) for polyphenylene ether and at least two poor solvents for the ether. In the above two or more poor solvents, it is indispensable to use a solvent (B) and a solvent (C) whose solubilities to water at 20C are 50 g/100 ml and 50 g/100 ml, respectively. and the polymerization form in the later period of the polymerization is precipitation-separation. In the method, the mass ratio of the solvent (B) to solvent (C) is within the range of 1.5:1-10:1.
Yoshio Narui
Yoshiaki Matsui
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