Described here are polyphenylene sulfide (PPS) polymers having significantly improved processability. It was surprisingly found that PPS polymers, terminated with specific end-capping agents in specific amounts, had significantly improved melt stability. Because of the significantly improved melt stability, the PPS polymers can be advantageously incorporated into melt processing techniques.

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. %.

Provided are a device for continuously producing poly(arylene sulfide) (hereinafter, referred to as PAS) and a method for continuous PAS production with which resource savings, energy savings, and a reduction in equipment cost are rendered possible. The device for continuous PAS production according to the present invention includes a housing chamber for housing a plurality of reaction cells; wherein the housing chamber is supplied with at least an organic amide solvent, a sulfur source, and a dihalo aromatic compound. In the reaction cells, the sulfur source is polymerized with the dihalo aromatic compound in the organic amide solvent to form a reaction mixture. The reaction cells communicate with each other through a gas phase within the housing chamber. The reaction cells are sequentially connected, and the reaction mixture sequentially moves to each reaction cell.

Provided are a device for continuously producing poly(arylene sulfide) (hereinafter, referred to as PAS) and a method for continuous PAS production with which resource savings, energy savings, and a reduction in equipment cost are rendered possible. The device for continuous PAS production according to the present invention includes a housing chamber for housing a plurality of reaction cells; wherein the housing chamber is supplied with at least an organic amide solvent, a sulfur source, and a dihalo aromatic compound. In the reaction cells, the sulfur source is polymerized with the dihalo aromatic compound in the organic amide solvent to form a reaction mixture. The reaction cells communicate with each other through a gas phase within the housing chamber. The reaction cells are sequentially connected, and the reaction mixture sequentially moves to each reaction cell.

The present invention provides a method for producing granular polyarylene sulfide (PAS) with increased average particle size and enhanced particle strength, a method for increasing the average particle size of granular PAS, a method for enhancing the particle strength of granular PAS, and granular PAS. The method for producing PAS according to the present invention includes: step 1: a preparation step of preparing a mixture containing an organic amide solvent, a sulfur source, water, a dihalo aromatic compound, and an alkali metal hydroxide; step 2: a pre-stage polymerization step of initiating a polymerization reaction by heating the mixture to produce a prepolymer having a dihalo aromatic compound conversion ratio of not less than 50% in the presence of less than an equimolar amount of an alkali metal hydroxide per 1 mol of the sulfur source; step 3: a post-stage polymerization step of continuing the polymerization reaction in the presence of not less than an equimolar amount of an alkali metal hydroxide per 1 mol of the sulfur source to obtain a reaction product mixture; and step 4: a cooling step of cooling the reaction product mixture after the post-stage polymerization step; wherein step 4 is performed in the presence of at least one type of auxiliary agent such as a carboxylate.

The present invention is to provide a method of producing highly pure polyarylene sulfide (PAS) while the produced amount per unit volume is enhanced and side reactions are suppressed. The method of producing PAS according to an embodiment of the present invention, the method including: a preparation step of preparing a mixture containing an organic amide solvent, a sulfur source, water, a dihalo aromatic compound, and an alkali metal hydroxide in an amount that is less than an equimolar amount per 1 mol of the sulfur source; a first-stage polymerization of heating the mixture; an alkali addition step of adding the alkali metal hydroxide, in an amount that is not less than an equimolar amount per 1 mol of the sulfur source, into the mixture that has undergone the first-stage polymerization step; a concentration step of removing at least a part of the organic amide solvent and/or at least a part of the water in the mixture that has undergone the first-stage polymerization step; and a second-stage polymerization step of heating the mixture that has undergone the alkali addition step and the concentration step and continuing the polymerization reaction.

The present invention is to provide a method of producing highly pure polyarylene sulfide (PAS) while the produced amount per unit volume is enhanced and side reactions are suppressed. The method of producing PAS according to an embodiment of the present invention, the method including: a preparation step of preparing a mixture containing an organic amide solvent, a sulfur source, water, a dihalo aromatic compound, and an alkali metal hydroxide in an amount that is less than an equimolar amount per 1 mol of the sulfur source; a first-stage polymerization of heating the mixture; an alkali addition step of adding the alkali metal hydroxide, in an amount that is not less than an equimolar amount per 1 mol of the sulfur source, into the mixture that has undergone the first-stage polymerization step; a concentration step of removing at least a part of the organic amide solvent and/or at least a part of the water in the mixture that has undergone the first-stage polymerization step; and a second-stage polymerization step of heating the mixture that has undergone the alkali addition step and the concentration step and continuing the polymerization reaction.

The present invention is to provide a method of producing highly pure polyarylene sulfide (PAS) while the produced amount per unit volume is enhanced and side reactions are suppressed. The method of producing PAS according to an embodiment of the present invention, the method including: a preparation step of preparing a mixture containing an organic amide solvent, a sulfur source, water, a dihalo aromatic compound, and an alkali metal hydroxide in an amount that is less than an equimolar amount per 1 mol of the sulfur source; a first-stage polymerization of heating the mixture; an alkali addition step of adding the alkali metal hydroxide, in an amount that is not less than an equimolar amount per 1 mol of the sulfur source, into the mixture that has undergone the first-stage polymerization step; a concentration step of removing at least a part of the organic amide solvent and/or at least a part of the water in the mixture that has undergone the first-stage polymerization step; and a second-stage polymerization step of heating the mixture that has undergone the alkali addition step and the concentration step and continuing the polymerization reaction.

The present invention is to provide a method of producing highly pure polyarylene sulfide (PAS) while the produced amount per unit volume is enhanced and side reactions are suppressed. The method of producing PAS according to an embodiment of the present invention, the method including: a preparation step of preparing a mixture containing an organic amide solvent, a sulfur source, water, a dihalo aromatic compound, and an alkali metal hydroxide in an amount that is less than an equimolar amount per 1 mol of the sulfur source; a first-stage polymerization of heating the mixture; an alkali addition step of adding the alkali metal hydroxide, in an amount that is not less than an equimolar amount per 1 mol of the sulfur source, into the mixture that has undergone the first-stage polymerization step; a concentration step of removing at least a part of the organic amide solvent and/or at least a part of the water in the mixture that has undergone the first-stage polymerization step; and a second-stage polymerization step of heating the mixture that has undergone the alkali addition step and the concentration step and continuing the polymerization reaction.