Abstract: The present invention relates to a crosslinked poly(meth)acrylic acid nitroxide compound resulting from crosslinking of a poly(meth)acrylic acid nitroxide compound, and an object of the present invention is to provide a method of inexpensively and easily producing a crosslinked poly(meth)acrylic acid nitroxide compound having a high radical concentration. The present invention is a method of producing a crosslinked poly(meth)acrylic acid nitroxide compound including a repeating unit represented by the general formula (2): (in the formula, R represents a hydrogen atom or a methyl group), comprising a nitroxidation step carried out in a state that a crosslinked poly(meth)acrylic acid imino compound resulting from crosslinking of a poly(meth)acrylic acid imino compound including a repeating unit represented by the general formula (1): (in the formula, R represents the same group as that represented by R in said general formula (2)) is dispersed in water.

Abstract: A water-absorbent resin is provided which is suitable for absorbing polymer-containing viscous liquids, wherein the specific surface area measured by the BET multipoint technique using krypton gas as the adsorption gas is no less than 0.05 m2/g, and the water retention capacity for 0.9 wt % physiological saline is 5-30 g/g.

Abstract: It is an object of the invention to provide a method of producing a crosslinked poly(meth)acrylic acid compound, in particular a method of producing a crosslinked poly(meth)acrylic acid nitroxide compound, which is a radical compound excellent in solvent stability.

Abstract: A process for preparing a water-absorbent resin made from an ?,?-unsaturated carboxylic acid as an essential monomer characterized in that the process comprises allowing a metal chelating agent to be present at any step in the process in an amount of 0.001 to 6 parts by weight, based on 100 parts by weight of the ?,?-unsaturated carboxylic acid; and adding a reducing agent or an oxidizing agent thereto in an amount of 0.001 to 6 parts by weight, based on 100 parts by weight of the ?,?-unsaturated carboxylic acid before initiation of drying and/or during drying of a gelated product containing a water-absorbent resin obtained by polymerization.

Abstract: A water-absorbent resin is provided which is suitable for absorbing polymer-containing viscous liquids, wherein the specific surface area measured by the BET multipoint technique using krypton gas as the adsorption gas is no less than 0.05 m2/g, and the water retention capacity for 0.9 wt % physiological saline is 5-30 g/g.

Abstract: It is an object of the invention to provide a method of producing a crosslinked poly(meth)acrylic acid compound, in particular a method of producing a crosslinked poly(meth)acrylic acid nitroxide compound, which is a radical compound excellent in solvent stability.

Abstract: A water-absorbent resin is provided which is suitable for absorbing polymer-containing viscous liquids, wherein the specific surface area measured by the BET multipoint technique using krypton gas as the adsorption gas is no less than 0.05 m2/g, and the water retention capacity for 0.9 wt % physiological saline is 5-30 g/g.

Abstract: The present invention provides novel polyaminopyridines which are excellent in solubility in various solvents, and are preferably used in a polymer-type organic electroluminescent material, and a process for preparing the same. More particularly, the present invention provides polyaminopyridines having a repetition structural unit represented by the following general formula (1); and having a number average molecular weight in a range of 500 to 1000000.

Abstract: A process for preparing a water-absorbent resin made from an ?,?-unsaturated carboxylic acid as an essential monomer characterized in that the process comprises allowing a metal chelating agent to be present at any step in the process in an amount of 0.001 to 6 parts by weight, based on 100 parts by weight of the ?,?-unsaturated carboxylic acid; and adding a reducing agent or an oxidizing agent thereto in an amount of 0.001 to 6 parts by weight, based on 100 parts by weight of the ?,?-unsaturated carboxylic acid before initiation of drying and/or during drying of a gelated product containing a water-absorbent resin obtained by polymerization.

Abstract: A carboxyl group-containing polymer composition comprising 100 parts by weight of a carboxyl group-containing polymer (A) prepared by copolymerizing an ?,?-unsaturated carboxylic acid (a) with a compound (b) having at least two ethylenic unsaturated groups; and 0.01 to 20 parts by weight of at least one compound (B) selected from an ester (c) obtained from a polyhydric alcohol and a fatty acid, and an alkylene oxide adduct of an ester (d) obtained from a polyhydric alcohol and a fatty acid. Since the carboxyl group-containing polymer composition is excellent in the solubility in water and gives the aqueous solution excellent thickening property, the polymer composition can be suitably used as a thickener for various aqueous solutions.

Abstract: A water-absorbing resin which has a specific surface area, as measured by the BET multipoint adsorption method employing krypton as an adsorbate gas, of 0.05 m2/g or larger and a water retentivity, as measured with 0.9 wt. % physiological saline, of 5 to 30 g/g. It is suitable for absorbing viscous liquids containing a high-molecular compound.

Abstract: A polymer composition containing carboxyl group which is excellent in water solubility, thickening properties and flow characteristics. This composition comprises (A) a cross-linked polymer comprising (a) an &agr;,&bgr;-unsaturated carboxylic acid and (b) a compound having at least two ethylenically unsaturated groups, and (B) at least one polymer selected from among polymers comprising vinylpyrrolidone as an essential monomer and polyethylene oxide.

Abstract: A process for preparing a water-absorbent resin is provided which enables the water-absorbent resin to ensure the reduction in the release amount of liquid and the increase in the liquid diffusibility. In the preparation process, the water-absorbent resin is prepared by polymerization of a water-soluble ethylenic unsaturated monomer. The polymerization of the water-soluble ethylenic unsaturated monomer is allowed to take place in the presence of a water-absorbent resin having a water-absorbing rate different from that of a water-absorbent resin resulting from polymerization of the water-soluble ethylenic unsaturated monomer. In a preferred mode, the polymerization is performed by a reversed-phase suspension polymerization method.

Abstract: A polymer composition containing carboxyl group which is excellent in water solubility, thickening properties and flow characteristics. This composition comprises (A) a crosslinked polymer comprising (a) an &agr;,&bgr;-unsaturated carboxylic acid and (b) a compound having at least two ethylenically unsaturated groups, and (B) at least one polymer selected from among polymers comprising vinylpyrrolidone as an essential monomer and polyethylene oxide.

Abstract: A method for producing a highly concentrated aqueous acrylic amide-based polymer dispersion which is inexpensive, good in fluidity and easy to handle is provided. The method comprises polymerizing a water-soluble monomer composition containing an acrylic amide monomer in an aqueous solution of an inorganic salt in the presence of a homopolymer of vinylpyrrolidone and/or a copolymer of vinylpyrrolidone and other monomer(s).

Abstract: A polymer composition containing carboxyl groups which has excellent water solubility, thickening properties and flow characteristics. The composition comprises (A) a crosslinked polymer comprising (a) an .alpha.,.beta.-unsaturated carboxylic acid and (b) a compound having at least two ethylenically unsaturated groups, and (B) at least one polymer comprising N-vinylpyrrolidone as essential monomer.

Abstract: There is provided an industrially advantageous process for producing a crosslinked polymer containing carboxyl groups which comprises (a) polymerizing an .alpha.,.beta.-unsaturated carboxylic acid and a crosslinking agent copolymerizable with it in the presence of a radical polymerization catalyst in an inert solvent, (b) heating the polymerized product in the presence of a radical scavenger and (c) removing the solvent. The polymer dissolved in water has high viscosity and excellent flowing properties.

Abstract: The present invention is directed to a method for production of alkylene oxide polymers comprising reacting an alkylene oxide in an inert hydrocarbon solvent in the presence of a catalyst. The method of the present invention offers alkylene oxide polymers with a great commercial value and a high degree of polymerization which can be produced industrially advantageously with high reproducibility by the use of a catalyst obtained by a simple procedure of applying heat treatment to the product obtained by reacting an organic zinc compound with particular aliphatic polyhydric alcohol and monohydric alcohol.

Abstract: Water-absorbent resins having improved water-absorbency, water-absorption rate and water-dispersibility can be produced by crosslinking a water-absorbent resin comprising a carboxylate as a constituent of the resin with a crosslinking agent having at least two functional groups in the presence of water in a proportion of 0.01 to 1.3 parts by weight per part by weight of the resin in an inert solvent.

Abstract: Water-absorbent resins having improved water-absorbency, water-absorption rate and water-dispersibility can be produced by crosslinking a water-absorbent resin comprising a carboxylate as a constituent of the resin with a crosslinking agent having at least two functional groups in the presence of water in a proportion of 0.01 to 1.3 parts by weight per part by weight of the resin in an inert solvent.