Abstract: Provided is a method of purifying a polyarylene sulfide by washing it with a mixture of an aprotic organic solvent and an alkyl halide, or with a mixture prepared by adding a halogenoaromatic compound having an electron-withdrawing group to an aprotic organic solvent. The method makes it possible to reduce the impurities such as alkali metal halides in polyarylene sulfide, thus giving thermally stable polyarylene sulfide.

Abstract: Provided are a polyarylene sulfide having a chloroform soluble content of at most 0.5% by weight and having an inherent viscosity &eegr;inh of from 0.05 to 0.4; a polyarylene sulfide resin composition comprising a polyarylene sulfide and an inorganic filler, of which the chloroform soluble content is at most 0.5% by weight relative to the polyarylene sulfide in the composition; car parts produced through injection molding of the composition; and a method for producing a polyarylene sulfide. The polyarylene sulfide has a reduced content of low-molecular components, and has well balanced properties of fluidity, flexural strength and impact resistance.

Abstract: A process for separating a solid compound other than lithium hydroxide, such as sodium chloride, in which lithium hydroxide is hydrosulfurized by bubbling gaseous hydrogen sulfide through an aprotic solvent, such as a polar organic compound, containing lithium hydroxide and the solid compound other than lithium hydroxide, solid-liquid separation is conducted under a condition in which the reaction of lithium hydrosulfide to lithium sulfide and hydrogen sulfide is suppressed and at a temperature of the liquid for separation at 50 to 150° C., and the separated crystal cake is further washed with the aprotic solvent to highly recover lithium hydrosulfide.

Abstract: Provided is a polyarylene sulfide resin composition having well-balanced fluidity and mechanical strength. The composition is such that its spiral flow length, x (mm), to give a molding having a thickness of 1 mm and the flexural strength, y (MPa), of the molding satisfy the following numerical formula (I), and comprises (A) from 50 to 70 parts by weight of a polyarylene sulfide resin, (B) from 30 to 50 parts by weight of glass fibers and (C) from 0 to 3 parts by weight, relative to 100 parts by weight of the polyarylene sulfide resin (A), of a coupling agent. y≧−(3x/10)+340  (I) wherein x falls between 100 and 300.

Abstract: Provided are a polyarylene sulfide having a chloroform soluble content of at most 0.5% by weight and having an inherent viscosity &eegr;inh of from 0.05 to 0.4; a polyarylene sulfide resin composition comprising a polyarylene sulfide and an inorganic filler, of which the chloroform soluble content is at most 0.5% by weight relative to the polyarylene sulfide in the composition; car parts produced through injection molding of the composition; and a method for producing a polyarylene sulfide. The polyarylene sulfide has a reduced content of low-molecular components, and has well balanced properties of fluidity, flexural strength and impact resistance.

Abstract: A method for producing an anhydrous alkali metal sulfide, which entails a) bubbling a solution of an alkali metal hydroxide in an aprotic organic solvent, such as N-alkylcaprolactam or N-alkylpyrrolidone, with hydrogen sulfide gas at a temperature between 50 and 250° C., thereby forming a product containing alkali metal hydrosulfide, and then b) terminating the hydrogen sulfide introduction after the system has come to contain substantially no water remaining therein, and heating the system, thereby effecting dehydrosulfurization to form the alkali metal sulfide.

Abstract: Provided is a polyarylene sulfide resin composition of which the moldings are burred little and which has good mechanical properties and good flow moldability. The composition comprises from 20 to 90% by weight of a polyarylene sulfide and from 10 to 80% by weight of an inorganic filler, and is characterized in that its burrs are on the level of at most 120 &mgr;m, that it has a weld strength of at least 50 MPa and that the length of its spiral flow having a thickness of 1 mm is at least 100 mm. Preferably, the polyarylene sulfide to be in the composition has a specific index to the degree of branching and a specific flexural strength.

Abstract: This invention provides a method for producing polyarylene sulfide continuously, comprising; 1) polymerization step wherein polyarylene sulfide is polymerized from a sulfur compound in the liquid or gas state and a dihalogenated aromatic compound in non-protonic organic solvent, 2) separation step wherein mixture of the polymerization solution and the washing solution is separated into the polymer phase and the solvent phase, and in said separation step said polymer phase is continuously taken out in the liquid state. The method of this invention makes it possible to produce polyarylene sulfide of high purity that it is suitable for molding and injection molding of the seat, the film, the fiber, etc. for the electronic and electric material field etc., with high-molecular-weight and low content of by-products, efficiently and economically.

Abstract: By mixing an alumina gel suspension prepared by dispersing alumina gel in pure water in an alumina concentration of 0.1 to 12% by weight, with an aqueous metal salt solution wherein a compound of a Group VIA metal and a compound of a Group VIII metal are dissolved, and then evaporating water to dry while stirring the mixture, the metal component can be loaded effectively on the alumina gel to a sufficiently high loading quantity, and active catalyst compositions useful as catalysts being superior in functions, such as activities, to the conventional hydrogenation catalysts are easily obtainable. Sufficiently desulfurized hydrocarbons are obtainable by allowing the catalyst compositions to contact sulfur-containing hydrocarbons in the presence of hydrogen.