Abstract: A method for the production of a water-absorbent agent comprises mixing an absorbent resin containing a carboxyl group with an additive soluble in the aqueous solution of at least one member selected from the group consisting of inorganic acids, organic acids, and polyamino acids and a cross-linking agent capable of reacting with the carboxyl group. A water-absorbent agent obtained by adding from 0.005 to 8 parts by weight of an epoxy compound to 100 parts by weight of a water-absorbent resin, exhibiting an absorption capacity without load of at least 45 (g/g), an absorption capacity under load of 20 g/cm2 of not less than 30 (ml/g) and having a residue amount of an epoxy compound of not more than 2 ppm. A water-absorbent composition comprises a polyamino acid (salt) and a water-absorbent resin containing a carboxyl group.

Abstract: A method for the production of a water-absorbent agent comprises mixing an absorbent resin containing a carboxyl group with an additive soluble in the aqueous solution of at least one member selected from the group consisting of inorganic acids, organic acids, and polyamino acids and a cross-linking agent capable of reacting with the carboxyl group. A water-absorbent agent obtained by adding from 0.005 to 8 parts by weight of an epoxy compound to 100 parts by weight of a water-absorbent resin, exhibiting an absorption capacity without load of at least 45 (g/g), an absorption capacity under load of 20 g/cm2 of not less than 30 (ml/g) and having a residue amount of an epoxy compound of not more than 2 ppm. A water-absorbent composition comprises a polyamino acid (salt) and a water-absorbent resin containing a carboxyl group.

Abstract: A method for the production of a water-absorbent agent comprises mixing an absorbent resin containing a carboxyl group with an additive soluble in the aqueous solution of at least one member selected from the group consisting of inorganic acids, organic acids, and polyamino acids and a cross-linking agent capable of reacting with the carboxyl group. A water-absorbent agent obtained by adding from 0.005 to 8 parts by weight of an epoxy compound to 100 parts by weight of a water-absorbent resin, exhibiting an absorption capacity without load of at least 45 (g/g), an absorption capacity under load of 20 g/cm2 of not less than 30 (ml/g) and having a residue amount of an epoxy compound of not more than 2 ppm. A water-absorbent composition comprises a polyamino acid (salt) and a water-absorbent resin containing a carboxyl group.

Abstract: A method for the production of a water-absorbent agent comprises mixing an absorbent resin containing a carboxyl group with an additive soluble in the aqueous solution of at least one member selected from the group consisting of inorganic acids, organic acids, and polyamino acids and a cross-linking agent capable of reacting with the carboxyl group. A water-absorbent agent obtained by adding from 0.005 to 8 parts by weight of an epoxy compound to 100 parts by weight of a water-absorbent resin, exhibiting an absorption capacity without load of at least 45 (g/g), an absorption capacity under load of 20 g/cm2 of not less than 30 (ml/g) and having a residue amount of an epoxy compound of not more than 2 ppm. A water-absorbent composition comprises a polyamino acid (salt) and a water-absorbent resin containing a carboxyl group.

Abstract: A method for the production of a water-absorbent agent comprises mixing an absorbent resin containing a carboxyl group with an additive soluble in the aqueous solution of at least one member selected from the group consisting of inorganic acids, organic acids, and polyamino acids and a cross-linking agent capable of reacting with the carboxyl group. A water-absorbent agent obtained by adding from 0.005 to 8 parts by weight of an epoxy compound to 100 parts by weight of a water-absorbent resin, exhibiting an absorption capacity without load of at least 45 (g/g), an absorption capacity under load of 20 g/cm2 of not less than 30 (ml/g) and having a residue amount of an epoxy compound of not more than 2 ppm. A water-absorbent composition comprises a polyamino acid (salt) and a water-absorbent resin containing a carboxyl group.

Abstract: A water-absorbent resin is produced by dispersing a solid blowing agent having an average particle diameter within a range of from 1 &mgr;m to 100 &mgr;m in an aqueous monomer solution containing an unsaturated monomer and a cross-linking agent, and then polymerizing the unsaturated monomer. The water-absorbent resin has excellent water absorption characteristics, such as improved dispersion and absorption rate of aqueous fluid, enhanced water retention capacity and dry touch, lower water-soluble component content, and lower residual monomer content. When a water-absorbent resin composition using the water-absorbent resin is used for, for example, a sanitary material, it is possible to improve the absorption rate and water retention capacity, and prevent leakage of fluid from the sanitary material.

Abstract: The invention provides a production process of a water-absorbent resin, by which process the polymerization temperature can be controlled in static aqueous solution polymerization. The production process of a water-absorbent resin comprises the step of polymerizing statically an aqueous solution with a thickness of 10˜50 mm including a hydrophilic monomer, and is characterized in that the polymerization heat is removed using both cooling due to heat conduction transfer and cooling due to the latent heat of vaporization, thereby controlling the maximum attained temperature of the polymerization system in the range of 60˜95°C. or controlling the increase in solid content in the range of 0.2 to 10 weight %.

Abstract: A hydrophilic polymer is denatured with a gaseous denaturant or a powdery denaturant substance made from a liquid denaturant substance. The liquid denaturant substance is made into powders by, for example, a method of mixing the liquid denaturant substance with a water-insoluble compound, a method of cooling the liquid denaturant substance to or below its melting point to turn the same into a solid state. Consequently, the hydrophilic polymer can be denatured uniformly. In case that the hydrophilic polymer is denatured with a gaseous denaturant, the hydrophilic polymer and denaturant react with each other efficiently in a safe manner regardless of the size or shape of the hydrophilic polymer. In case that the hydrophilic polymer is denatured with the powdery denaturant substance, not only the liquid denaturant substance which is substantially in the solid state can be mixed with the hydrophilic polymer, but also the denaturation timing can be readily controlled.

Abstract: A method for the production of a water-absorbent resin capable of fast water absorption is disclosed which comprises the steps of dispersing bubbles of an inert gas in an aqueous monomer solution of a mixture of a water-soluble unsaturated monomer and a water-soluble cross-linking monomer and subjecting the mixture to copolymerization under the condition that a volume of the monomer solution wherein the inert gas is dispersed is in the range of 1.02 to 5 times of a volume of non-dispersant state.

Abstract: A water-absorbent resin is produced by crushing a mass of crosslinked hydrogel polymer having high adhesion and elastic properties without kneading it, and drying the crushed crosslinked hydrogel polymer. In the case when the crosslinked hydrogel polymer includes cells therein, the crosslinked hydrogel polymer is crushed so as to restrain reduction in the number of cells contained in the crosslinked hydrogel polymer. The crosslinked hydrogel polymer is crushed by any of crushing methods including: shearing the crosslinked hydrogel polymer with a fixed blade and a rotary blade; cutting the crosslinked hydrogel polymer with a cutter having a pair of rotary blades that are mounted on different shafts and rotate while at least partly overlapping each other; cutting the crosslinked hydrogel polymer with a cutter having a rotary blade using a lubricant; and crushing the crosslinked hydrogel polymer after freezing.

Abstract: A water content of a water-containing gel of a hydrophilic cross-linked polymer is reduced by pressuring (calendaring) it. Then, a gel composition including, for example, a water-containing gel including cross-linked poly(meth)acrylic acid (salt), glycerol (polyhydric alcohol) and polyester fibers (auxiliary forming material), etc., is fed to a drum dryer on an upstream side of a pressurizing roller. Then, the resulting gel composition is pressurized (calendared) heated by a pressurizing roller to be formed into a sheet. As a result, a sheet-like absorbent material having at least one smooth surface can be obtained. The absorbent material resulting from the described method shows excellent properties and especially absorbing properties such as absorbing rate, absorbency under load, and shape retaining properties.

Abstract: A water-absorbent resin is produced by dispersing a solid blowing agent having an average particle diameter within a range of from 1 .mu.m to 100 .mu.m in an aqueous monomer solution containing an unsaturated monomer and a cross-linking agent, and then polymerizing the unsaturated monomer. The water-absorbent resin has excellent water absorption characteristics, such as improved dispersion and absorption rate of aqueous fluid, enhanced water retention capacity and dry touch, lower water-soluble component content, and lower residual monomer content. When a water-absorbent resin composition using the water-absorbent resin is used for, for example, a sanitary material, it is possible to improve the absorption rate and water retention capacity, and prevent leakage of fluid from the sanitary material.

Abstract: This invention concerns an absorbent composite a supporting member and a cationic absorbent polymer and anionic absorbent polymer particles fixed to the supporting member. This absorbent composite excels in absorbing capacity under pressure, vertical aspiration power, and flexibility and suffers only sparing exfoliation of an absorbent polymer. This invention further concerns an absorbent composite which contains an absorbent polymer in an amount of at least 30% by weight based on the total weight of the absorbent composite and, after absorbing a liquid, shows a value of not less than 3 for the expansion anisotropy specified by the following formula.Expansion anisotropy=(Ez/Ex+Ez/Ey)/2(wherein Ex, Ey, and Ez respectively represent coefficient of liner expansion in the directions of X axis, Y axis, and Z axis) and an absorbent article using the absorbent composite.

Abstract: A method for the production of a water-absorbent agent comprises mixing an absorbent resin containing a carboxyl group with an additive soluble in the aqueous solution of at least one member selected from the group consisting of inorganic acids, organic acids, and polyamino acids and a cross-linking agent capable of reacting with the carboxyl group. A water-absorbent agent obtained by adding from 0.005 to 8 parts by weight of an epoxy compound to 100 parts by weight of a water-absorbent resin, exhibiting an absorption capacity without load of at least 45 (g/g), an absorption capacity under load of 20 g/cm.sup.2 of not less than 30 (ml/g) and having a residue amount of an epoxy compound of not more than 2 ppm. A water-absorbent composition comprises a polyamino acid (salt) and a water-absorbent resin containing a carboxyl group.

Abstract: In a body fluid-absorbing article composed of a liquid-permeable front-surface member, a liquid-impermeable rear-surface member, and a fibrous absorbent member nipped therebetween and adapted to be used with the front-surface member held in contact with the human body, by the improvement having disposed in half of the thickness of the absorbent member on the front-surface member side an absorbent composite (A) obtained by applying an ethylenically unsaturated monomer capable of forming an absorbent polymer by polymerization or an aqueous solution of the monomer to a fibrous web and thereafter polymerizing the monomer.