A polyphenylene sulfide monofilament is characterized by having a continuous heat-shrinking stress variation of at most 5% and a size uniformity (U %, Normal value) of at most 1.2%; and a drum-shaped fiber package includes the wound polyphenylene sulfide monofilament described. The polyphenylene sulfide monofilament has a very small aperture variation rate and is optimal for high-precision filters.

A polyarylene ether sulfone comprising in polymerized form A) isosorbide, isomannide, isoidide or a mixture thereof and B) at least one at least one nonsulfonated dihalodiaryl sulfone (compound B) and C) at least one sulfonated dihalodiaryl sulfone (compound C), a process for its preparation and its use in the preparation of coatings, films, fibers, foams, membranes or molded articles.

In order to provide a copolymerized polyphenylene sulfide fiber that is thin, has a low heat shrinkage rate, and is suitable for a use as a paper-making binder having excellent weldability, a copolymerized polyphenylene sulfide fiber is characterized by containing a copolymerized polyphenylene sulfide that has a p-phenylene sulfide unit as a main component and contains 3 mol % or more and 40 mol % or less of a m-phenylene sulfide unit in a repeating unit, and having a degree of crystallization of 10.0% or more and 30.0% or less, an average fiber diameter of 5 μm or more and 25 μm or less, and further a shrinkage rate in 98° C. hot water of 25.0% or less.

A poly(phenylene sulfide) fiber changes little in fiber structure and has excellent long-term heat resistance. Namely, the poly(phenylene sulfide) fiber has a degree of crystallization of 45.0% or higher, a content of movable amorphous components of 15.0% or less, and a weight-average molecular weight of 300,000 or less.

A method for producing a nonwoven fabric is provided. The method includes spinning a molten aromatic polysulfone resin from a nozzle and extending it with a high temperature fluid ejected at high speed, thereby obtaining the aromatic polysulfone resin in a fibrous form, and collecting the aromatic polysulfone resin obtained in a fibrous form on a moving collecting member. The aromatic polysulfone resin has a melt mass flow rate of 130 g/10 min or more under conditions of a test temperature of 400° C. and a nominal load of 2.16 kg, which is determined based on ASTM D 1238. A distance from the nozzle to the collecting member is set to 30 mm or less.

A polyarylene ether copolymer comprising i) at least one block comprising in polymerized form A) isosorbide, isomannide, isoidide or a mixture thereof and B) at least one unit comprising at least one difunctional compound comprising at least one dichlorodiaryl sulfone, a dichlorodiaryl ketone or a mixture thereof and ii) at least one block comprising in polymerized form C) at least one polyalkylene oxide, a process for its preparation and its use in the preparation of coatings, films, fibers, foams, membranes or molded articles.

Dimensionally-stable fibrous structures including ceramic-coated melt-blown nonwoven fibers made of a flame-retarding polymer and processes for producing such fire-resistant nonwoven fibrous structures. The melt-blown fibers include poly(phenylene sulfide) in an amount sufficient for the nonwoven fibrous structures to pass one or more fire-resistance test, e.g. UL 94 V0, FAR 25.853 (a), FAR 25.856 (a), and CA Title 19, without any halogenated flame-retardant additive, and have a ceramic coating. The melt-blown fibers are subjected to a controlled in-flight heat treatment at a temperature below a melting temperature of the poly(phenylene sulfide) immediately upon exiting from at least one orifice of a melt-blowing die, in order to impart dimensional stability to the fibers. The nonwoven fibrous structures including the in-flight heat-treated melt-blown fibers exhibit a Shrinkage less than a Shrinkage measured on a nonwoven fibrous structure including only fibers not subjected to the controlled in-flight heat treatment operation, generally less than 15%.

A polyphenylene sulfide short fiber has a monofilament fineness of 0.70 to 0.95 dtex, a strength of 4.5 to 5.5 cN/dtex, a fiber length of 20 to 100 mm, and a melt flow rate (MFR) value of 200 to 295 g/10 min. The polyphenylene sulfide short fiber enables improvements to be made in the dust collection performance and mechanical strength without impairing the fiber productivity or felt productivity.

The obtained hollow fiber membrane has high water permeability, and has, when used as a humidifying membrane, a linear relationship between supply humidity and humidification amount. Therefore, the hollow fiber membrane is effectively used, for example, as a humidifying membrane for fuel cells. The method for producing a polyphenylsulfone hollow fiber membrane according to present invention can provide a humidifying membrane that suppresses segregation and crosslinking of hydrophilic polymers associated with the operation of the humidifying membrane, and that prevents the deterioration of humidification performance due to the operation. In addition, the producing method of the present invention can produce a polyphenylsulfone hollow fiber membrane for humidifying membranes, wherein the hollow fiber membrane has high water permeability, and has, when used as a crosslinked humidifying membrane, a linear relationship between water vapor supply humidity and humidification amount.

Dimensionally stable fire-resistant fibrous structures including fire-resistant melt-blown nonwoven fibers, and processes and apparatus for producing such dimensionally stable, fire-resistant nonwoven fibrous structures. The melt-blown fibers include poly(phenylene sulfide) in an amount sufficient for the nonwoven fibrous structures to pass one or more fire-resistance test selected from UL 94 V0, FAR 25.853 (a), and FAR 25.856 (a), without any halogenated flame-retardant additive in the nonwoven fibrous structure. The melt-blown fibers are subjected to a controlled in-flight heat treatment at a temperature below a melting temperature of the poly(phenylene sulfide) immediately upon exiting from at least one orifice of a melt-blowing die, in order to impart dimensional stability to the fibers. The nonwoven fibrous structures including the in-flight heat treated melt-blown fibers exhibit a Shrinkage less than a Shrinkage measured on an identically-prepared structure including only fibers not subjected to the controlled in-flight heat treatment operation, and generally less than 15%.