Abstract: This invention relates to: a molding material comprising a bundle of continuous reinforcing fibers (A), a polyarylene sulfide prepolymer (B) comprising at least 50% by weight of cyclic polyarylene sulfide and having the weight average molecular weight of less than 10,000 or polyarylene sulfide (B?) having the weight average molecular weight of 10,000 or greater and the degree of dispersion of 2.

Abstract: A polyarylene sulfide h as a narrow molecular weight distribution and a high molecular weight and high purity which is industrially useful, wherein the polyarylene sulfide has a weight average molecular weight of 10,000 or more, and weight loss when heated, ?Wr=(W1?W2)/W1×100?0.18(%) (wherein ?Wr is weight loss ratio (%), W1 is sample weight when arrived at 100° C. and W2 is sample weight when arrived at 330° C.). Its production method includes a polyarylene sulfide prepolymer which contains a cyclic polyarylene sulfide at least 50 wt % or more, and of which weight average molecular weight is less than 10,000 is heated to be converted to a high polymer of which weight average molecular weight is 10,000 or more.

Abstract: This invention provides a method for producing a polyarylene sulfide, comprising the step of bringing a low-hydrated alkali metal sulfide containing respectively 0.05 to less than 0.8 mole of water and an organic amide solvent per mole of the sulfur contained in the alkali metal sulfide, into contact with a dihalogenated aromatic compound in an organic polar solvent for polymerization. This invention also provides a polyarylene sulfide obtained by the method. The problem to be solved by this invention is to provide a method for efficiently producing a polyarylene sulfide in a short time using an alkali metal sulfide small in water content and organic amide solvent content.

Abstract: This invention provides a method for producing a polyarylene sulfide, comprising the step of bringing a low-hydrated alkali metal sulfide containing respectively 0.05 to less than 0.8 mole of water and an organic amide solvent per mole of the sulfur contained in the alkali metal sulfide, into contact with a dihalogenated aromatic compound in an organic polar solvent for polymerization. This invention also provides a polyarylene sulfide obtained by the method. The problem to be solved by this invention is to provide a method for efficiently producing a polyarylene sulfide in a short time using an alkali metal sulfide small in water content and organic amide solvent content.