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. %.

A method is provided for preparing a low temperature thermosetting polyarylene sulfide having significantly low crystallinity while maintaining a low melt flow rate at a high polymerization yield, so as to ensure excellent laser welding property and mechanical properties even when used in a molded product on the transmitting side of laser beam by a laser welding method.

A method is provided for preparing a low temperature thermosetting polyarylene sulfide having significantly low crystallinity while maintaining a low melt flow rate at a high polymerization yield, so as to ensure excellent laser welding property and mechanical properties even when used in a molded product on the transmitting side of laser beam by a laser welding method.

The present invention provides a production method and a production apparatus for a polyarylene sulfide (PAS), thus the formation of a floating polymer and the leakage of the floating polymer to the outside of the vessel in a washing step are prevented, to achieve steady production of the polymer with high quality, to improve the yield of the polymer and to reduce environmental load, wherein the floating polymer refers to a particles of the polymer which are floating on the surface of a washing solution, in the upper part of the inside of a washing vessel, as a result of the adhesion of a gas onto the surface of the particles of the polymer. The present invention provides a production method for a PAS comprising step (I), performing polymerization, step (II), separating and collecting a polymer, step (III), washing a slurry, and step (IV), collecting the polymer after washing, wherein an aqueous medium is sprayed onto a PAS floating on the surface of the aqueous washing solution in the upper part of the inside of the washing vessel in step (III) (step (IIIa), washing a slurry using a counter current, and/or step (IIIb), treating a slurry with acid using a counter current, or the like); and a production apparatus for a PAS comprising a washing device (counter current washing device and/or a counter current contact/acid treatment device or the like) having an aqueous medium spray means.

The present invention provides a production method and a production apparatus for a polyarylene sulfide (PAS), thus the formation of a floating polymer and the leakage of the floating polymer to the outside of the vessel in a washing step are prevented, to achieve steady production of the polymer with high quality, to improve the yield of the polymer and to reduce environmental load, wherein the floating polymer refers to a particles of the polymer which are floating on the surface of a washing solution, in the upper part of the inside of a washing vessel, as a result of the adhesion of a gas onto the surface of the particles of the polymer. The present invention provides a production method for a PAS comprising step (I), performing polymerization, step (II), separating and collecting a polymer, step (III), washing a slurry, and step (IV), collecting the polymer after washing, wherein an aqueous medium is sprayed onto a PAS floating on the surface of the aqueous washing solution in the upper part of the inside of the washing vessel in step (III) (step (IIIa), washing a slurry using a counter current, and/or step (IIIb), treating a slurry with acid using a counter current, or the like); and a production apparatus for a PAS comprising a washing device (counter current washing device and/or a counter current contact/acid treatment device or the like) having an aqueous medium spray means.

The present invention relates to a method for separating volatile substances, particularly iodine, diiodised aromatic compounds and/or mixtures thereof, from material mixtures containing said compounds. The invention further relates to a device for producing polyarylene sulphides, by means of which volatile substances, particularly iodine and diiodised aromatic compounds, can be separated from the polymers.

The present invention relates to a method for separating volatile substances, particularly iodine, diiodised aromatic compounds and/or mixtures thereof, from material mixtures containing said compounds. The invention further relates to a device for producing polyarylene sulphides, by means of which volatile substances, particularly iodine and diiodised aromatic compounds, can be separated from the polymers.

There is provided a polyarylene sulfide configured to satisfy (1) to (4): (1) having a weight-average molecular weight of not less than 10000; (2) having a polydispersity of not greater than 2.5, wherein the polydispersity is expressed by a ratio of the weight-average molecular weight to a number-average molecular weight; (3) having a weight reduction on heating that satisfies an expression of Wr=(W1W2)/W11000.18(%) (where Wr denotes a weight reduction ratio (%) and is a value calculated from a sample weight (W2) at temperature reaching 330 C. relative to a sample weight (W1) at temperature reaching 100 C. in thermogravimetric analysis at a temperature rise rate of 20 C./minute in a non-oxidizing atmosphere at ordinary pressure); and (4) having a nitrogen content of not greater than 200 ppm.

There is provided a polyarylene sulfide configured to satisfy (1) to (4): (1) having a weight-average molecular weight of not less than 10000; (2) having a polydispersity of not greater than 2.5, wherein the polydispersity is expressed by a ratio of the weight-average molecular weight to a number-average molecular weight; (3) having a weight reduction on heating that satisfies an expression of Wr=(W1W2)/W11000.18(%) (where Wr denotes a weight reduction ratio (%) and is a value calculated from a sample weight (W2) at temperature reaching 330 C. relative to a sample weight (W1) at temperature reaching 100 C. in thermogravimetric analysis at a temperature rise rate of 20 C./minute in a non-oxidizing atmosphere at ordinary pressure); and (4) having a nitrogen content of not greater than 200 ppm.

A heat treated fine polyarylene sulfide powder. (i) The heat treated fine polyarylene sulfide powder is manufactured from separation liquid. (ii) The heat treated fine polyarylene sulfide powder is obtained by subjecting the separation liquid to solid-liquid separation to obtain a raw material fine powder polyarylene sulfide. Thereafter the raw material fine powder polyarylene sulfide is subjected to pre-heat treatment and heat treatment. (iii) The heat treated fine polyarylene sulfide powder has an average particle size of from 1 to 80 m. (iv) The heat treated fine polyarylene sulfide powder has a melt viscosity of 1 Pa.Math.s or greater. (v) A generated gas amount of the heat treated fine polyarylene sulfide is 10 ppm or less.