Abstract: A stannic acid anhydride represented by the structural formula shown below.

Abstract: By reacting a tin carboxylate with hydrogen peroxide at a particular ratio in an aqueous medium, this invention provides a transparent aqueous tin compound solution which can finally form, in an industrially advantageous manner, tin oxide having excellent transparency, uniformity, compactness, conductivity, etc.

Abstract: This invention provides a water-swellable fiber which is produced from a fiber having a particular cross-sectional structure and containing and linking carboxyl groups thereto at a prescribed degree of neutralization by causing a particular quantity of a specific alkali to adhere to said fiber. The fiber of the invention has no problems in respect to agglutination among the filaments upon storage, no problems upon processing, such as wet system paper-making, and no problems in neutralization thereof. This fiber exhibits sufficient water-swelling properties in use.

Abstract: A spinning solution of an acrylonitrile polymer is subjected to dry-wet spinning through an annular type spinneret having a non-perforated part, i.e. a part not formed with spinning orifices, extending from the outer periphery to the inner periphery. The spinneret has more than 3,000 spinning orifices, at the perforated part of the annular portion. The extruded fibers are then passed through a coagulation bath, and the coagulated fibers are then stretched. By this method, uniform acrylic fibers can be produced without causing quality unevenness and fiber defects due to uneven coagulation, filament agglutination, and fluctuation of the gap between spinneret lower surface and liquid surface of the coagulation bath.

Abstract: A bead-like glycidyl (meth)acrylate polymer is produced by aqueous suspension polymerization of glycidyl (meth)acrylate alone or a monomer mixture composed of more than 50 weight % of said monomer and at least one other monomer which forms the remainder, in the presence of a specific aqueous polymer, at a pH of from 2 to 9 and at a stirring speed of from 50 to 500 r.p.m. By heat treating said bead-like polymer at a pH below 3 and at a temperature above 70.degree. C., hydroxyl groups resulting from the ring opening of the epoxy groups are introduced, whereby a solvent-insoluble bead-like polymer having a gel water content not less than 30% is produced.

Abstract: This invention provides an aqueous antimony oxide sol composed of Sb.sub.6 O.sub.13, 1 to 100 m.mu. in particle diameter, dispersed in an aqueous medium or composed of said Sb.sub.6 O.sub.13 treated with a particular quantity of a particular organic silicon compound and regulated to within a prescribed pH range, which has a high concentration and a small quantity of impurities, and moreover has excellent thermal stability and chemical stability.

Abstract: The present invention provides a gel having excellent separation ability, operability and a long life, for separating useful components from a rhodanate-containing detoxication treated liquid. The gel consists of a cross-linked polymer with more than 50 weight % of repeating units which are composed of 2,3-dioxypropyl (meth)acrylate or 2,3-dioxypropyl (meth)allyl ether, and whose average particle diameter is more than 10.mu. and gel water content is from 30 to 150%. The present invention also provides a method of separation using said gel.

Abstract: Hard polyvinyl alcohol gel is produced by copolymerizing a carboxylic acid vinyl ester monomer with a particular cross-linking agent and then saponifying the copolymer. This hard polyvinyl alcohol gel has excellent mechanical strength and separation ability and has no problem in copolymerizability and polymerization speed. Moreover, it shows no change in cross-linked structure before and after saponification.

Abstract: This invention relates to a method of producing a flame-retardant acrylic polymer by polymerizing, in the presence of a radical polymerization initiator, a vinyl monomer containing acrylonitrile in an amount of more than 75 weight %, in an aqueous medium in which is present a halogen-containing polymer latex substantially free from an emulsifier. The acrylic polymer can provide flame-retardant shaped products, especially fibers, which have no problems in the operation of spinning, transparency, gloss, dyed color clearness, etc.

Abstract: The present invention provides a method of producing a softening agent in which a silicone resin containing particular functional groups, a particular emulsifier and a particular antistatic agent are dispersed stably in an aqueous medium in a particular ratio, and which can give durable slippery touch, softness and processability at the same time to fibers after treatment. The invention also provides an industrially advantageous method of producing acrylic fibers which have animal hair-like touch and processability by one-step treatment, by fixing said softening agent to the acrylic fibers.

Abstract: This invention relates to a method of producing a flame-retardant acrylic polymer by polymerizing, in the presence of a radical polymerization initiator, a vinyl monomer containing acrylonitrile in an amount of more than 75 weight %, in an aqueous medium in which is present a halogen-containing polymer latex substantially free from an emulsifier. The acrylic polymer can provide flame-retardant shaped products, especially fibers, which have no problems in the operation of spinning, transparency, gloss, dyed color clearness, etc.

Abstract: The present invention relates to a process for producing a packing material for use in liquid chromatography which comprises aqueous suspension polymerizing vinyl acetate, a (meth)acrylic acid ester or a glycidyl monovinyl ester or ether with a monomer mixture composed mainly of a cross-linking monomer in the presence of a diluent selected from among epichlorohydrin and glycidyl ethers and thereafter removing it from the resulting polymer particles by ring-opening the epoxy groups in said diluent. This process provides a packing material for use in liquid chromatography which is uniform and porous and moreover is excellent in mechanical strength.

Abstract: Novel porous water-absorbing acrylic fibers composed of not less than 90 weight % of an acrylonitrile polymer and having dispersed therein less than 10 weight % of a water-absorbing resin particles containing carboxyl groups (represented by --COOX wherein X is H, HN.sub.4 or an alkali-metal) and having a degree of water-swellability of 10-300 cc/g, the particle diameter of which resin is not larger than 0.5.mu. at absolute dryness, the carboxyl groups in the water absorbing resin present at least in the outer layer of the fibers being of the type where X is H, and in the inner portion being of the type where X is NH.sub.4 or an alkali metal, said fibers containing pores not smaller than 0.2.mu. in their largest diameter in the inner layer of the fibers and said fibers having a water holding ratio not lower than 20%. The acrylic fibers provided are novel, porous and water-absorbing, having a stable water-absorbing ability which will not be easily lowered by heat treatment, etc.

Abstract: In the suspension polymerization of acrylonitrile in an aqueous medium, the polymerization is conducted in the presence of a water-soluble polymer and an oil soluble radical initiator while maintaining the acrylonitrile concentration higher than 9 weight percent in the polymerization system, whereby the polymerization of acrylonitrile in the water phase is suppressed and a high molecular weight polymer (weight average molecular weight not less than 400,000) having uniform particle diameters is produced.

Abstract: Polyacrylonitrile (PAN) fiber of high strength (tensile strength.gtoreq.20 g/d) produced from a polymer composed mainly of acrylonitrile (AN) and having a weight average molecular weight not less than 400,000, and a method of producing said fiber characterized by a multistage stretching step and a drying step under particular conditions.

Abstract: Colloidal antimony oxide is produced by reacting hydrogen peroxide with antimony trioxide to form a colloidal salt of antimony oxide. In the reaction there is added to the reaction system 1.5 to 30 mol percent of an inorganic alkaline substance per mol of antimony trioxide.

Abstract: The present invention provides an industrial process for producing acrylic fibers having non-circular cross-sections which are excellent in gloss, softness, etc. In this process, which is a wet-spinning method using an inorganic solvent, a particular acrylonitrile polymer solution is spun through a spinnerette having circular spinning orifices. The steps of spinning, coagulation, water-washing and wet-heat stretching are carried out in integral combination and under specific conditions.

Abstract: A water-removing material usable for hydrophobic liquids consisting of a fiber assemblage containing water-swellable fibers, at least a part of the fiber outer layer of which is composed of a hydrophilic, cross-linked polymer and the remainder of which is composed of an acrylonitrile polymer and/or another polymer; and a water-removing filter formed into the shape of a tube by winding said fiber assemblage around an internal tubular support, or by compressing said fiber assemblage into the shape of a tube.

Abstract: A filter capable of separating and removing water semi-permanently from oil by effectively transforming water which is finely, stably dispersed in oil into coarse drops, which filter is composed of a fiber assembly formed with a particular binder, and a method for separating and removing water by passing the oil to be treated through said filter.

Abstract: In packing gels of different activities together into a liquid chromatographic column, this invention provides a method which makes it possible to obtain a remarkably elevated separation performance by packing a gel of high activity in a layer at the outlet side of the column for a length within the range of 5 to 60% of the total packing length.