Abstract: A method for reproducing lithium sulfide, including the steps of reacting lithium halide generated as a byproduct during the production of a polyarylene sulfide by a reaction between lithium sulfide and a halogenated aromatic compound with sodium carbonate to generate lithium sulfide, isolating the lithium carbonate and reacting the lithium carbonate with a sulfur compound to generate the lithium sulfide. According to the above method, lithium sulfide having a less Na content can be reproduced from lithium halide generated as a byproduct during the production of a polyarylene sulfide.

Abstract: There is disclosed a process for continuously producing a polyarylene sulfide which comprises reacting a sulfur source with a dihalogenated aromatic compound in an aprotic organic solvent, characterized by maintaining the content of the dihalogenated aromatic compound in the polymerization liquid after the substantial completion of the polymerization reaction at 5 mg/g or higher. It is made possible by the process according to the present invention to efficiently produce the polyarylene sulfide which has a high molecular weight and is excellent in thermal stability.

Abstract: There is disclosed a process for producing a polyarylene sulfide (PAS) which comprises reacting a sulfur source with a dihalogenated aromatic compound in the presence of an aprotic organic solvent, characterized in that the process comprises at least one polymerization reaction step wherein a polymer phase as a dispersed phase is in the form of spherical droplets. It is made possible by the continuous polymerization process to discharge the polymer phase and solvent phase from a polymerization vessel at a constant ratio and as a result, to maintain PAS composition (concentration) at a constant level at all times, and thus to provide a continuous PAS production process which is effective for enhancing its molecular weight and stabilizing the same.

Abstract: Provided is a production process for polyarylene sulfide having a high molecular weight and an excellent heat stability. It is a production process for polyarylene sulfide by reacting a dihalogenoaromatic compound with metal sulfide in a polar solvent, wherein all or a part of water required for the reaction is added on a condition that the reaction system is 100° C. or higher, whereby obtained is polyarylene sulfide which is reduced in an intrinsic viscosity [&eegr;] by 0.05 deciliter/g or less at 206° C. when added to an N-methyl-2-pyrrolidone solvent is the polyarylene sulfide of an amount equivalent to the solvent and it is maintained at 265° C. for 8 hours.

Abstract: Provided are a polyarylene sulfide resin and its 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: Provided is a production process for polyarylene sulfide having a high molecular weight and an excellent heat stability. It is a production process for polyarylene sulfide by reacting a dihalogenoaromatic compound with metal sulfide in a polar solvent, wherein all or a part of water required for the reaction is added on a condition that the reaction system is 100° C. or higher, whereby obtained is polyarylene sulfide which is reduced in an intrinsic viscosity [&eegr;] by 0.05 deciliter/g or less at 206° C. when added to an N-methyl-2-pyrrolidone solvent is the polyarylene sulfide of an amount equivalent to the solvent and it is maintained at 265° C. for 8 hours.

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: 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: A process for efficiently manufacturing polyarylene sulfide copolymer in which polymers are well dispersed and which copolymer exhibiting superior mechanical properties. The process comprises reacting a polyarylene sulfide resin (A) and an amination agent (B) in a non-protonic organic solvent (C), and copolymerizing the resulting amino polyarylene sulfide resin (A') and a reactive elastomer (D) in a non-protonic organic solvent (C'), thereby obtaining a polyarylene sulfide resin (A") with the elastomer dispersed in the resin matrix.

Abstract: A novel process for preparing lithium N-methylaminobutyrate, which is useful for preparation of poly(arylene sulfide) such as poly(phenylene sulfide). The process comprises reacting N-methyl-2-pyrrolidone with a hydroxide of an alkali metal other than lithium in an aprotic organic solvent, reacting the resulting reaction product mixture with lithium chloride after removing water therefrom and removing the alkali metal chloride formed as a by-product. According to this process, lithium N-methylaminobutyrate lithium free from alkali metal other than lithium, is easily prepared, which is easily recovered and recycled in the production of said polymers.

Abstract: Disclosed is a process for preparing a polyarylene sulfide, which involves polycondensing a dihalogenated aromatic compound with a source of sulfur in an organic polar solvent while dehydrating at pressure under which polycondensation is performed. This process avoids dehydration operation of the raw materials, particularly the source of sulfur, prior to polycondensation, thereby resulting in the production of the polyarylene sulfide having a high molecular weight.

Abstract: A process for preparing a granular polyarylene sulfide having a high molecular weight is a one-stage polycondensation process which involves subjecting a dihalogen aromatic compound to polycondensation with a source of sulfur in the presence of a polymerization aid in an organic polar solvent and setting the temperature for polycondensation to a range from 220.degree. C. to 248.degree. C. for a predetermined period of time prior to completion of polycondensation up to completion of polycondensation. The resulting granular polyarylene sulfide is suitable for molding or forming into sheets, films, fibers and so on, causes less burrs when subjected to injection molding, has a high molecular weight sufficient to create the property of forming a gel, and is easy to handle.

Abstract: A polyarylene sulfide has an inherent viscosity [.eta..sub.i n h ] of 0.1 to 0.5 dl/g, a weight-average molecular weight of 1.times.10.sup.4 to 2.times.10.sup.5 ; a ratio of the inherent viscosity [.eta..sub.i n h ] to a calculated viscosity [.eta.].sub.calc ([.eta..sub.i n h /[.eta.].sub.calc) of 0.4/1 to 0.8/1; and a degree of whiteness of 50 or higher when measured in accordance with whiteness testing procedures (JIS P8123). The polyarylene sulfide is prepared by reaction by contacting at least one member of a metallic sulfide (A) selected from an alkali metal sulfide and an alkali metal hydrosulfide with a dihalogen aromatic compound (B) and an aromatic compound (C) having three or more than three functional groups in a polar solvent in a molar ratio of the dihalogen aromatic compound (B) to the metallic sulfide (A) [(B)/(A)] ranging from 1.035/1 to 1.300/1 and in a molar ratio of the aromatic compound (C) to the dihalogen aromatic compound (B) [(C)/(B)] ranging from 0.003/1 to 0.05/1.

Abstract: A process for preparing a polyarylene sulfide involves dehydrating a mixture of a hydrous sulfur source and an organic polar solvent under a reduced pressure in a rectification tower and contacting a dihalogen aromatic compound with a dehydrated sulfur source in the organic polar solvent.This process provides the polyarylene sulfide with a white color and a higher molecular weight.

Abstract: A process for preparing a polyarylene sulfide involves contacting a sulfur source with a metallic salt of an aliphatic .omega.-hydroxycarboxylic acid and a dihalogen aromatic compound in an organic polar solvent, thereby carrying out polycondensation with stability in a polymerization system in which a water content is large. the polyarylene sulfide prepared has a high degree of whiteness and with a sufficiently high molecular weight. The use of the metallic salt of .omega.-hydroxycarboxylic acid in a particular range can provide a novel polyarylene sulfide.

Abstract: Polyarylene sulfides are produced by polymerizing a dihalogen aromatic compound with an alkali metal hydrosulfide in the presence of a lithium halide in an organic polar solvent. In this polymerization, an alkali metal hydroxide and/or carbonate is added and a branching agent such as a trihalogen aromatic compound or a halogen aromatic nitro compound is used, if desired.The polyarylene sulfides have a high molecular weight and a less salt contents and a high degree of whiteness.

Abstract: Polyarylene sulfides are prepared by reacting a dihalogen aromatic compound with a sodium hydrosulfide in the presence of an alkali metal aminoalkanoate and a lithium halide in an organic polar solvent. This process can prevent a decomposition of the sodium hydrosulfide during dehydration and produce the polyarylene sulfides in a granular form in high yields and with high efficiency.The polyarylene sulfides obtainable by this process are high in molecular weight and degree of whiteness and low in a content of salts remaining therein. Furthermore, the polyarylene sulfides are in the granular form so that they can be handled with ease because of their readily separability and washability.

Abstract: Disclosed is a method for producing a polyarylene sulfide comprising contacting a dihalogenated aromatic compound with an alkali metal sulfide in a polar solvent, wherein a halogenated aromatic compound containing active hydrogen is present in the reaction system.