| abstract |
(57) [Summary] An object of the present invention is to provide a method for producing PPS in which the recovery of unreacted monomers is facilitated in a cycle in which granular PPS is shortened. A method for producing a granular polyphenylene sulfide by polymerizing at least one sulfur source and a polyhaloaromatic compound in an organic polar solvent in a closed container and gradually cooling the mixture at a later stage of the polymerization reaction. In the late stage of the polymerization reaction, the mixture was gradually cooled so that at least 50% of the polymer was present in the form of solid granules, and the pressure in the closed vessel was 0.39 × 1 In the state of not less than 0 6 Pa, the pressure of the vessel is released, the polymerization reaction mixture comprising the gas phase and the liquid phase is degassed, and the pressure of the vessel is reduced to 0.20 × 10 6 Pa or more. Method for producing sulfide. |