A branched polyarylene sulfide resin includes an S substituent group with a cleaved disulfide compound, which has a halogen content of 4,000 ppm or less, a melt viscosity as measured at a temperature of 330 C. and a shear rate of 2 sec.sup.1 of 1.010.sup.4 to 50.010.sup.4 Pa.Math.s, and a melt viscoelasticity tan as measured at a temperature of 310 C. and an angular velocity of 1 rad/sec of 0.1 to 0.6.

A branched polyarylene sulfide resin includes an S substituent group with a cleaved disulfide compound, which has a halogen content of 4,000 ppm or less, a melt viscosity as measured at a temperature of 330 C. and a shear rate of 2 sec.sup.1 of 1.010.sup.4 to 50.010.sup.4 Pa.Math.s, and a melt viscoelasticity tan as measured at a temperature of 310 C. and an angular velocity of 1 rad/sec of 0.1 to 0.6.

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.sup.1) of 0.1 to 8000 Pa.Math.s produced by the method.

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.sup.1) of 0.1 to 8000 Pa.Math.s produced by the method.

A heat-resistant, chemical-resistant polyphenylene sulfide block copolymer containing polyphenylene sulfide units and aromatic polyester units, wherein the polyphenylene sulfide units have a number average molecular weight in the range of 6,000 to 100,000. Provided is a polyphenylene sulfide block copolymer that overcomes the disadvantages of block copolymers including a low-molecular-weight polyphenylene sulfide segment and having poor heat resistance and chemical resistance.

A heat-resistant, chemical-resistant polyphenylene sulfide block copolymer containing polyphenylene sulfide units and aromatic polyester units, wherein the polyphenylene sulfide units have a number average molecular weight in the range of 6,000 to 100,000. Provided is a polyphenylene sulfide block copolymer that overcomes the disadvantages of block copolymers including a low-molecular-weight polyphenylene sulfide segment and having poor heat resistance and chemical resistance.

To provide a polyarylene sulfide (hereinafter, PAS) manufacturing method and PAS manufacturing device that further eliminates processing costs in manufacturing PAS, by recovering from solid content containing an unreacted sulfur source and alkali metal halide produced as a byproduct the sulfur source and the solid content with a reduced amount of the sulfur source, and then conveniently and easily reusing the unreacted sulfur source without performing a large-scale process. A method of manufacturing PAS according to the present invention comprises: a polymerizing step of producing PAS; an extracting step of bringing an extraction solvent into content with solid content produced in the polymerizing step, and extracting at least a portion of a sulfur source from the solid content; a recovering step of separating and recovering the solid content passing through the extracting step and an extraction liquid produced in the extracting step; and a recycling step of supplying at least a portion of the extraction liquid preferably as at least a portion of PAS produced raw material in the polymerizing step; where the extraction solvent is (1) a protic organic solvent or (2) a mixed solvent containing water and an organic solvent, and the amount of the sulfur source in the solid content recovered in the recovering step is 2 parts by mass or less with regard to 100 parts by mass of the alkali metal halide.

To provide a polyarylene sulfide (hereinafter, PAS) manufacturing method and PAS manufacturing device that further eliminates processing costs in manufacturing PAS, by recovering from solid content containing an unreacted sulfur source and alkali metal halide produced as a byproduct the sulfur source and the solid content with a reduced amount of the sulfur source, and then conveniently and easily reusing the unreacted sulfur source without performing a large-scale process. A method of manufacturing PAS according to the present invention comprises: a polymerizing step of producing PAS; an extracting step of bringing an extraction solvent into content with solid content produced in the polymerizing step, and extracting at least a portion of a sulfur source from the solid content; a recovering step of separating and recovering the solid content passing through the extracting step and an extraction liquid produced in the extracting step; and a recycling step of supplying at least a portion of the extraction liquid preferably as at least a portion of PAS produced raw material in the polymerizing step; where the extraction solvent is (1) a protic organic solvent or (2) a mixed solvent containing water and an organic solvent, and the amount of the sulfur source in the solid content recovered in the recovering step is 2 parts by mass or less with regard to 100 parts by mass of the alkali metal halide.

Provided is a method for manufacturing fine polyarylene sulfide (PAS) powder, in which impurities such as alkali metal salts and/or PAS oligomers are reduced while the wettability of the fine PAS powder in a fine PAS powder-containing solid is retained after solid-liquid separation of a separation liquid obtained by subjecting a dispersion liquid containing granular PAS to separation into granular PAS and a separation liquid; and a fine PAS powder.

The method for manufacturing a fine PAS powder of the present invention includes: (a) separating granular PAS and a separation liquid from a dispersion liquid containing granular PAS, by solid-liquid separation using at least one screen that has an opening diameter of 75 to 180 m; (b) performing solid-liquid separation of the separation liquid to obtain a fine PAS powder-containing solid; (c) heating the fine PAS powder-containing solid to reduce an amount of an organic solvent to obtain a wet cake; and (d) washing the wet cake using an aqueous solvent. The water content of the wet cake after heating is at least 30 wt. %.

Provided is a method for manufacturing fine polyarylene sulfide (PAS) powder, in which impurities such as alkali metal salts and/or PAS oligomers are reduced while the wettability of the fine PAS powder in a fine PAS powder-containing solid is retained after solid-liquid separation of a separation liquid obtained by subjecting a dispersion liquid containing granular PAS to separation into granular PAS and a separation liquid; and a fine PAS powder.

The method for manufacturing a fine PAS powder of the present invention includes: (a) separating granular PAS and a separation liquid from a dispersion liquid containing granular PAS, by solid-liquid separation using at least one screen that has an opening diameter of 75 to 180 m; (b) performing solid-liquid separation of the separation liquid to obtain a fine PAS powder-containing solid; (c) heating the fine PAS powder-containing solid to reduce an amount of an organic solvent to obtain a wet cake; and (d) washing the wet cake using an aqueous solvent. The water content of the wet cake after heating is at least 30 wt. %.