A polyphenylene sulfide resin composition for automotive cooling parts contains, with respect to 100 parts by weight of a polyphenylene sulfide resin (A): 30 to 110 parts by weight of glass fibers (B); and 0.1 to 3 parts by weight of a silane compound (C) having a functional group selected from an amino group and an isocyanate group. In this polyphenylene sulfide resin composition, the PPS resin (A) has a number-average molecular weight of 7,000 to 14,000, and gives a residue amount of 2.0 to 5.0% by weight when dissolved in 20-fold amount by weight of 1-chloronaphthalene at 250° C. for 5 minutes and subsequently subjected to heat pressure filtration through a PTFE membrane filter having a pore size of 1 μm.

A method for producing a polyarylene sulfide comprising: initiating a polymerization reaction by heating a mixture containing an organic polar solvent, a sulfur source, water, a polyhaloaromatic compound, and an alkali metal hydroxide in the presence of at least one auxiliary agent selected from the group consisting of carboxylates and the like, to form a reaction mixture containing a prepolymer having a conversion rate of a polyhaloaromatic compound of 50 mol % or greater, then a phase separation agent addition step of adding a phase separation agent into the reaction mixture, then continuing the polymerization reaction, and then cooling the reaction mixture, in the cooling step, the coolant being added to the reaction mixture at a temperature that is at least 5° C. higher than a maximum thickening temperature and lower than 250° C., and a cooling rate at the maximum thickening temperature being 2.2° C./min or higher and 3.9° C./min or lower.

A method for producing a polyarylene sulfide comprising: initiating a polymerization reaction by heating a mixture containing an organic polar solvent, a sulfur source, water, a polyhaloaromatic compound, and an alkali metal hydroxide in the presence of at least one auxiliary agent selected from the group consisting of carboxylates and the like, to form a reaction mixture containing a prepolymer having a conversion rate of a polyhaloaromatic compound of 50 mol % or greater, then a phase separation agent addition step of adding a phase separation agent into the reaction mixture, then continuing the polymerization reaction, and then cooling the reaction mixture, in the cooling step, the coolant being added to the reaction mixture at a temperature that is at least 5° C. higher than a maximum thickening temperature and lower than 250° C., and a cooling rate at the maximum thickening temperature being 2.2° C./min or higher and 3.9° C./min or lower.

To provide a method for producing PAS by which PAS having a small particle size of 50 μm or greater and 550 μm or less as an average particle size can be produced.

In the method for producing PAS, including: (1) a preparation step of preparing a prepared mixture containing an organic polar solvent, a sulfur source, and a dihalo aromatic compound; (2) a pre-stage polymerization step of initiating a polymerization reaction by heating the prepared mixture to produce a prepolymer; (3) a phase separation step of adding water as a phase separation agent to a reaction mixture in a reaction system to form a phase separation state; and (4) a post-stage polymerization step of continuing the polymerization reaction after the phase separation step, in which an organic sulfonic acid metal salt having a specific solubility in water is contained in the prepared mixture or the reaction mixture.

Provided is a resin composition for molding containing a polyarylene sulfide resin that forms a molded body having all of mechanical strength, heat cycle characteristics, and thermal conductivity in a well-balanced manner. Specifically, provided are a resin composition for molding containing a plate-like filler having an aspect ratio of 10 to 500 (A), a polyarylene sulfide resin (B), a thermoplastic resin having a glass transition temperature (Tg) of 20° C. or lower (C), and glass fibers (D) as essential components, the plate-like filler (A) being contained in an amount of 30 to 70 parts by mass relative to 100 parts by mass of the sum of the plate-like filler (A), the polyarylene sulfide resin (B), the thermoplastic resin (C), and the glass fibers (D), and a molded body of the resin composition for molding.

A polyarylene sulfide in which when the cumulative integral value from the molecular weight of 100 to the molecular weight of 10,000 in a molecular weight distribution curve is 100, the cumulative integrated value at the molecular weight of 4000 is 48 to 53, and when the melt flow rate of the polyarylene sulfide is defined as MFR1, and when the melt flow rate obtained after mixing the polyarylene sulfide with an epoxy silane coupling agent at a weight ratio of 100:1 and heating the resulting mixture at 315.5° C. for 5 minutes is defined as MFR2, the rate of change represented by MFR2/MFR1 is not more than 0.085.

A polyarylene sulfide in which when the cumulative integral value from the molecular weight of 100 to the molecular weight of 10,000 in a molecular weight distribution curve is 100, the cumulative integrated value at the molecular weight of 4000 is 48 to 53, and when the melt flow rate of the polyarylene sulfide is defined as MFR1, and when the melt flow rate obtained after mixing the polyarylene sulfide with an epoxy silane coupling agent at a weight ratio of 100:1 and heating the resulting mixture at 315.5° C. for 5 minutes is defined as MFR2, the rate of change represented by MFR2/MFR1 is not more than 0.085.

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 method for producing polyarylene sulfide that can have a high melt viscosity while suppressing ultra-fine powder generation. The method for producing polyarylene sulfide includes: (1) preparing a prepared mixture containing an organic polar solvent, a sulfur source, and a dihalo aromatic compound; (2) initiating a polymerization reaction by heating the prepared mixture to produce a prepolymer; (3) adding water as a phase separation agent to a reaction mixture in a reaction system to form a phase-separated state; and (4) continuing the polymerization reaction after phase separation. In the method, when a dihalo aromatic compound conversion ratio is 80 mass % or greater and 93 mass % or less and after the prepolymer reaches a weight average molecular weight of 10000 or greater in the first-stage polymerization step, an aromatic compound having 3 or more halogen atoms bonded to an aromatic ring is added to the reaction mixture.