A hollow fiber filtration membrane in which even when a relatively small contaminant having a size close to that of a permeation effective component is present in a filtration solution, Flux decrease over time during filtration is suppressed, and a useful component can be efficiently recovered, the hollow fiber filtration membrane including a polysulfone-based polymer and a hydrophilic polymer and having a large number of pores, the hollow fiber filtration membrane having a gradient asymmetric porous structure in which an average pore diameter of the pores increases from an outer surface portion toward an inner surface portion of the membrane, a content of the hydrophilic polymer of the membrane being from 6.0 to 10.0% by mass, a ratio between a content of the hydrophilic polymer at the inner surface portion and the content of the hydrophilic polymer of the membrane being in the range of from 0.50 to 0.80.

A hollow fiber filtration membrane in which even when a relatively small contaminant having a size close to that of a permeation effective component is present in a filtration solution, Flux decrease over time during filtration is suppressed, and a useful component can be efficiently recovered, the hollow fiber filtration membrane including a polysulfone-based polymer and a hydrophilic polymer and having a large number of pores, the hollow fiber filtration membrane having a gradient asymmetric porous structure in which an average pore diameter of the pores increases from an outer surface portion toward an inner surface portion of the membrane, a content of the hydrophilic polymer of the membrane being from 6.0 to 10.0% by mass, a ratio between a content of the hydrophilic polymer at the inner surface portion and the content of the hydrophilic polymer of the membrane being in the range of from 0.50 to 0.80.

Provided are: a high-melting-point resin fiber having heat resistance and solvent resistance, offering excellent workability/formability, and having a diameter of 4 μm or less; and a nonwoven fabric including the high-melting-point resin fiber. Also provided is a method for efficiently producing a high-melting-point resin fiber having a diameter of 4 μm or less, via laser melt electrospinning. The high-melting-point resin fiber according to the present invention includes a resin having a melting point of 250° C. or higher and has a diameter of 4 μm or less. In the high-melting-point resin fiber, the resin having a melting point of 250° C. or higher is preferably a PEEK. The fiber preferably has a degree of crystallinity of 30% or less.

Fibrous structures and more particularly to fibrous structures that exhibit improved TEWL properties, for example lower TEWL % Difference Values as measured according to the TEWL Test Method described herein, compared to known fibrous structures, sanitary tissue products comprising such fibrous structures and method for making such fibrous structures are provided.

Fibrous structures and more particularly to fibrous structures that exhibit improved TEWL properties, for example lower TEWL % Difference Values as measured according to the TEWL Test Method described herein, compared to known fibrous structures, sanitary tissue products comprising such fibrous structures and method for making such fibrous structures are provided.

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 polymetalloxane is described having a constituent unit represented by the following general formula (1):

##STR00001##

wherein R.sup.1, R.sup.2, R.sup.3, M a, b and m are as defined.

The problem is to provide a porous membrane with a reduced phenomenon in which membranes firmly adhere to one another during production of the porous membrane (membrane adhesion). The problem is solved by a porous membrane comprising a hydrophobic polymer and a hydrophilic polymer, wherein an average value T of ratios of the number of counts of ions derived from the hydrophilic polymer to the number of counts of ions derived from the hydrophobic polymer is 1.0 or more when a surface of the porous membrane is measured by time-of-flight secondary ion mass spectrometry (TOF-SIMS).

The problem is to provide a porous membrane with a reduced phenomenon in which membranes firmly adhere to one another during production of the porous membrane (membrane adhesion). The problem is solved by a porous membrane comprising a hydrophobic polymer and a hydrophilic polymer, wherein an average value T of ratios of the number of counts of ions derived from the hydrophilic polymer to the number of counts of ions derived from the hydrophobic polymer is 1.0 or more when a surface of the porous membrane is measured by time-of-flight secondary ion mass spectrometry (TOF-SIMS).