US Patent 7834133 Production process of poly(arylene sulfide)

A process for producing a poly(arylene sulfide) including a charging step 1 of preparing a charging mixture containing an organic amide solvent, a sulfur source, an alkali metal hydroxide, water and a dihalo-aromatic compound and having a pH of at least 12.5; a first-stage polymerization step 2 of heating the mixture 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 3 of adding a phase separation agent into the reaction system and adding an alkali metal hydroxide in an amount corresponding to 1 to 10 mol % per mol of the charged sulfur source at a time or in portions, thereby continuing the polymerization reaction.