Patent ID: 7569656
Filing Date: 2009-08-04
Classification: C08G

Abstract:
1. A method for producing a poly (arylene sulfide) in which a dihalo-aromatic compound and an alkali metal sulfide are polymerized by heating in an organic amide solvent in a polymerizer, which comprises: (1) after the polymerization process, initiating a cooling process for cooling a polymerization reaction system comprising a liquid phase containing the poly(arylene sulfide) produced and the organic amide solvent and a vapor phase containing a gas component (A); and (2) in the cooling process, (i) cooling the gas component (A) in the vapor phase in a reflux condenser provided above the polymerizer and equipped with a jacket through which coolant is passed, wherein vapor phase from the polymerization reaction system passes through a valve to the reflux condenser, and wherein an exhaust valve is located above the reflux condenser, thereby condensing a high boiling gas component (A2) with a boiling point equal to or higher than water, which is present in the vapor phase and includes water vapor, an unreacted dihalo-aromatic compound and the organic amide solvent, (ii) refluxing the condensate back into the polymerization reaction system, and thereby cooling the polymerization reaction system comprising the liquid phase, and (iii) reducing the content of a low boiling gas component (A a) exhausting the low boiling gas component (A1) from the polymerization system through the exhaust valve located above the reflux condenser; b) allowing at least a part of the low boiling gas component (A1) to be absorbed in the liquid phase by adding an alkali metal hydroxide into the liquid phase to react at least a part of the low boiling gas component (A1) with the alkali metal hydroxide in the liquid phase; or c) both a) and b), wherein a gradual cooling by the above cooling process is conducted to reduce the temperature of the liquid phase such that the liquid phase becomes slurry containing a granular solid of the poly (arylene sulfide).