Patent ID: 7834133

Claim:
A process for producing a poly(arylene sulfide) by polymerizing a sulfur source and a dihalo-aromatic compound in an organic amide solvent, the process comprising: a dehydration step of heating a mixture containing the organic amide solvent, the sulfur source and an alkali metal hydroxide to discharge at least a part of a distillate containing water from an interior of a system containing the mixture to an exterior of the system; a charging step of preparing a charging mixture containing the organic amide solvent, the sulfur source, the alkali metal hydroxide, water and the dihalo-aromatic compound and having a pH of 12.5-13.5 as measured by a pH meter; a first-stage polymerization step in a uniformly dissolved state of a reaction mixture of heating the charging mixture to a temperature of 170 to 270° C. to initiate a polymerization reaction, thereby forming a prepolymer that a conversion of the dihalo-aromatic compound is at least 50%; and a second-stage polymerization step in a phase-separated state of adding a phase separation agent into the reaction system containing the prepolymer and adding an alkali metal hydroxide in an amount corresponding to 1 to 10 mol % per mol of the sulfur source at a time or in portions, thereby continuing the polymerization reaction at a temperature of 240 to 290° C.