Polyarylene sulfide production method and polyarylene sulfide

Abstract

A method of producing polyarylene sulfide (PAS) by subjecting a sulfur source and a dihalo aromatic compound (DHA) to polymerization reaction in an organic amide solvent under alkaline conditions, the method suppressing side reactions or the like and yielding PAS having a high degree of polymerization at a high yield is provided; and PAS having a high degree of polymerization are provided. A method of producing PAS, including: a preparation step of preparing a preparation mixture containing an organic amide solvent, a sulfur source, an alkali metal hydroxide, water, and DHA, and having a pH of 12.5 or higher; a first-stage polymerization step of heating the preparation mixture to 170° C. or higher to initiate a polymerization reaction and continuing the polymerization reaction at 240 to 280° C., thereby forming a prepolymer having a DHA conversion rate of 50% or greater (at this time, a temperature increasing rate from 220° C. to 240° C. is lower than a temperature increasing rate for 240° C. or higher); and a second-stage polymerization step of adding, in the reaction system, an alkali metal hydroxide in an amount of 1 to 20 mol % per 1 mol of the sulfur source in the presence of a phase separation agent to continue the polymerization reaction at 245 to 290° C. PAS having a melt viscosity (310° C.; shear rate: 1216 sec) of 0.1 to 8000 Pa·s produced by the method.