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AssigneeTonen Chemical Corporation
InventorsYoichi Imai, Osamu Komiyama, Kazuhiro Ichikawa
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A particle size of potyarylene sulfide obtained in polymerization is controlled by a process characterized in that a gaseous phase part of a reactor is cooled or heated after starting decreasing a temperature of a reaction system o an end of precipitation of polyarylene sulfide formed In an embodiment, a water content in the reaction system is 0.8 to 1.7 moles per mole of the alkali metal sulfide; the gaseous phase part of the reactor is cooled in a polymerization stage to thereby condense a part of a gaseous phase in the reactor and the condensed liquid is refluxed to a liquid phase in the reactor; and the gaseous phase part is only cooled after starting decreasing the temperature of the reaction system, whereby high molecular weight polyarylene sulfide suitable for powder coating is formed, which has a weight average molecular weight of at least 30,000 and an average particle size of 50 to 80 .mu.m, wherein particles of 40 to 150 .mu.m account for at least 90% by weight of the whole particles in a particle size distribution, and the amount of particles of 180 .mu.m or more is 0.5% by weight or less.
A process for the preparation of polyarylene sulfide by reacting an alkali metal sulfide with a dihaloaromatic compound in an organic amide solvent at an elevated temperature, characterized in that a gaseous phase part of a reactor is separately cooled to a temperature lower than a temperature of a liquid phase of the reactor, or separately heated to a temperature higher than a temperature of a liquid phase of the reactor after starting decreasing a temperature of a reaction system to thereby control a particle size of a product polyarylene sulfide.
In a process for preparing a polyarylene sulfide by reacting an alkali metal sulfide with a dihaloaromatic compound in an organic amide solvent at elevated temperature in a reactor to form a gaseous phase and a liquid phase and then cooling the reaction mixture whereby polyarylene sulfide product precipitates, the improvement wherein the particle size of the polyarylene sulfide product can be controlled by separately heating the gaseous phase of the reaction mixture to a temperature higher than the temperature of the liquid phase or separately cooling the gaseous phase of the reaction mixture to a temperature lower than the temperature of the liquid phase of the reaction mixture, prior to or after the reaction mixture is cooled.
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