Patent attributes
A process for producing polyarylene sulfide includes: steps of reacting an aromatic dihalide compound and an alkaline metal compound in a polar organic solvent for polymerization under heating and cooling a system including the reaction mixture to recover particulate polyarylene sulfide (PAS). The system after the reaction is gradually cooled at an average cooling speed of 0.2 to 1.0 deg. C./min. selectively in a temperature range of from 1 deg. C. below to 1 deg. C. above a maximum system-viscosity temperature. As a result, the process can be operated at a relatively short polymerization cycle and yet provides the product PAS particles with a high and stable bulk density as to exhibit good processability in the transportation and storage, and excellent transportability in a hopper or a screw of an extruder or a molding machine.
