Abstract: A fiber of sea-islands phase separation wherein the sea component comprises a vinyl alcohol based polymer with high orientation and great crystallinity and the islands component comprises a water-insoluble cellulose based polymer with excellent absorptivity of alkaline solutions, thermal resistance and heat fusion resistance, and wherein the size of the islands is 0.03 to 10 .mu.m and the strength is 3 g/d or more, is readily disintegrated into a fibril of a diameter of 0.05 to 8 .mu.m when a mechanical stress is imposed onto the fiber wet in water.From the fibril with good hydrophilicity, high strength, great particle captivity and excellent reinforcing performance, and additionally with good absorptivity of alkaline solutions and great thermal resistance and heat fusion resistance, none of the fiber components therein is solubilized during fibrillation. Neither a beating process nor a beating solution causes foaming or environmental pollution.

Abstract: A reinforcing material for incorporation into a kneaded and shaped hydraulic material, comprising a fiber having a fineness of 5 d or more, an aspect ratio of from 10-500, a breaking tenacity of 5 g/d or more, an elongation (A) of from 6-20%, a flexing tenacity utilization factor (B) of 35% or more, and (B).ltoreq.4 (A).

Abstract: A vinyl-alcohol-based polymer and vinyl-halide-based polymer are dissolved in a common organic solvent for them, a typical example of which is dimethylsulfoxide, to obtain a dope wherein a solution of the vinyl-halide-based polymer having a particle size of 1-50 .mu.m is present in the solution of the vinyl-alcohol-based polymer. This dope is spun into a low temperature solidifying bath comprising a solidifying solvent such as methanol, and the organic solvent. The resultant is subjected to extraction, drying, dry heat drawing, and optional heat shrinking or acetalization to obtain fiber. In the fiber thus obtained, the vinyl-alcohol-based polymer makes sea phases, and the vinyl-halide-based polymer makes island phases whose size is 0.1-3 .mu.m. The crystallinity degree of the vinyl-alcohol-based polymer is 65-85%.The polyvinyl-alcohol-based flame retardant fiber is useful for clothes, industrial materials, living materials and the like.

Abstract: A fiber of sea-islands phase separation wherein the sea component comprises a vinyl alcohol based polymer with high orientation and great crystallinity and the islands component comprises a water-insoluble cellulose based polymer with excellent absorptivity of alkaline solutions, thermal resistance and heat fusion resistance, and wherein the size of the islands is 0.03 to 10 .mu.m and the strength is 3 g/d or more, is readily disintegrated into a fibril of a diameter of 0.05 to 8 .mu.m when a mechanical stress is imposed onto the fiber wet in water. From the fibril with good hydrophilicity, high strength, great particle captivity and excellent reinforcing performance, and additionally with good absorptivity of alkaline solutions and great thermal resistance and heat fusion resistance, none of the fiber components therein is solubilized during fibrillation. Neither a beating process nor a beating solution causes foaming or environmental pollution.

Abstract: A fiber of sea-islands phase separation wherein the sea component comprises a vinyl alcohol based polymer with high orientation and great crystallinity and the islands component comprises a water-insoluble cellulose based polymer with excellent absorptivity of alkaline solutions, thermal resistance and heat fusion resistance, and wherein the size of the islands is 0.03 to 10 .mu.m and the strength is 3 g/d or more, is readily disintegrated into a fibril of a diameter of 0.05 to 8 .mu.m when a mechanical stress is imposed onto the fiber wet in water.From the fibril with good hydrophilicity, high strength, great particle captivity and excellent reinforcing performance, and additionally with good absorptivity of alkaline solutions and great thermal resistance and heat fusion resistance, none of the fiber components therein is solubilized during fibrillation. Neither a beating process nor a beating solution causes foaming or environmental pollution.

Abstract: By dissolving a vinyl alcohol polymer (A) and an incompatible vinyl polymer (B), preferably an acrylonitrile polymer in a common solvent to prepare a spinning stock solution of a phase separation structure wherein the polymer (B) is present at particle sizes of 2 to 50 .mu.m, and wet spinning or dry-wet spinning the resulting spinning stock solution in a solidifying bath containing a mixture of an organic solvent capable of solidifying both the polymers (A) and (B) and the solvent of the spinning stock solution at a weight ratio of 25/75 to 85/15, thereby drawing the resulting yarn by 8-fold or more, a fiber is provided; and from the fiber can be produced a fibril with good hydrophilicity, a higher strength, and excellent heat fusion resistance, along with excellent wiping performance, filtering performance, micro-particle capturing properties and reinforcing performance, readily, stably and inexpensively.

Abstract: By mixing a high-melting polyvinyl alcohol type polymer (A) and a low-melting water-soluble polymer (B) in a solvent for the polymer (A) to prepare a spinning solution and then subjecting the solution to low-temperature spinning so that the resulting filaments are solidified uniformly in the cross-sectional direction, there is formed a fiber of sea-islands structure comprising said high-melting polyvinyl alcohol type polymer (A) as the sea component and said low-melting water-soluble polymer (B) as the islands component. In this fiber, at least part of the islands component is present in a fiber zone ranging from the fiber surface to 2 .mu.m inside and the fiber surface contains substantially no islands component. This fiber ordinarily shows the performance of the matrix phase, i.e.

Abstract: The process of the present invention comprises wet spinning or dry-jet-wet spinning a PVA-based polymer soluble in water at not more than 100.degree. C. while using a dope solvent and a solidifying solvent each comprising an organic solvent, wet drawing the solidified filaments, subjecting the drawn filaments to extraction treatment and then drying, and further subjecting the filaments to heat shrinking treatment under multi-stage temperature elevation condition. The water soluble fibers of the present invention obtained by this process, while having a low water dissolution temperature of not more than 100.degree. C., have a markedly small maximum shrinkage in water and has high tensile strength and small ash content. The water soluble fibers of the present invention are suitably used for chemical lace base fabrics and blended yarns with wool or jute.

Abstract: Provided are high-performance polyvinyl alcohol fibers having excellent resistances to hot water and dry heat as well as excellent strength and elastic modulus. The fibers are produced from a highly syndiotactic polyvinyl alcohol containing units from vinyl pivalate in an appropriate amount, which renders it possible to draw the highly crystalline fiber in a high drawing ratio of at least 16.

Abstract: High-strength polyvinyl alcohol fiber is provided by extruding a polyvinyl alcohol dope solution through a spinneret into a coagulating bath, the spinneret being located such that substantially only its dope-extruding surface contacts the coagulating bath. This process can produce stably and at a low cost polyvinyl alcohol fibers with excellent strength.

Abstract: The polysulfone hollow fiber membrane provided by the present invention can prohibit bacteria, bacilli, viruses and the like, and is therefore useful, besides as an industrial filter for water purification, as a membrane for body fluid filtration or condensation. In particular, the polysulfone hollow fiber membrane is, being excellent in removing .beta..sub.2 -MG, markedly useful as a membrane for treating body fluid such as hemodialysis and hemofiltration.

Abstract: Heat resistant organic fibers comprising a wholly aromatic polymer having amide group and/or imide group, said fibers having properties satisfying the following formulasTm.gtoreq.350.degree. C.,Tm-Tex.gtoreq.30.degree. C.Xc.gtoreq.10%DE.gtoreq.10%DSR(Tm).ltoreq.15%, and ##EQU1## wherein Tm is a melting point; Tex is an exotherm starting temperature; Xc is a degree or crystallization; DE is an elongation; DSR is a dry shrinkage factor at Tm; and DSR(Tm+55.degree. C.) is a dry shrinkage factor at Tm+55.degree. C. The process for producing the fibers is also disclosed.

Abstract: A reinforced therapeutic tube which is excellent in kink resistance, pressure resistance and flexibility. The tube is made of an elastomeric material with a reinforcing material spirally embedded into the tube wall, and at least one of the tubular parts where no spiral reinforcing material exists. The tip end of the reinforcing material which is wound in spiral shape is bent parallel to the inside surface of the tube and inward of the tube for at least one or more pitches of the spiral, and at least the tip of the reinforcing material bent is buried into the inside wall of the tube.

Abstract: A filtration apparatus for removing undesirable components from a solution to be treated, comprises a module in which a number of hollow fibers are fixed at one end thereof by cast-molding materials, and is opened at the end portion above described and closed at another end portion thereof, in which said solution to be treated can be kept from leaking out of a mechanically sealed portion. Any defect in the sealed portion can be detected from the outside by the provision of an opening which leads the leaked solution to the outside of the apparatus, instead of allowing it to combine with the filtrate. The apparatus is preferably used for the manufacture of purified water which is free from bacteria, pyrogene, and the like. Ultra-purified water of remarkably high purity can be obtained when the apparatus is used as a check filter in a process for manufacturing ultra-purified water.