Abstract: The present invention provides a novel acrylic acid crosslinked polymer and the use thereof. The present invention provides the acrylic acid crosslinked polymer in which the content of soluble components is 40 wt. % or higher. The present invention also provides a method for adjusting the viscosity of a fracturing fluid in a hydraulic fracturing method, the viscosity adjustment method including: A) a step of measuring the types and quantities of metal cations which are in water and which are the object of viscosity adjustment; B) a step of selecting the type and quantity of an acrylic acid crosslinked polymer on the basis of the types and quantities of metal cations and the pH so as to achieve a viscosity that is required for fracturing in a hydraulic fracturing method; and C) a step of adjusting the viscosity of the fracturing fluid using the acrylic acid crosslinked polymer of the selected type and quantity.

Abstract: A water-absorbing resin having a high swollen gel elastic modulus, a high swelling capacity and a method for producing the same are provided where the water-absorbing resin includes a water soluble unsaturated monomer having a dissociable group, an internal crosslinked structure index expressed by the following numerical formula of 14 or more, a weight average molecular weight (Mw) after a hydrolysis treatment of 220,000 or less, and a molecular weight distribution (Mw/Mn) after a hydrolysis treatment of 3.40 or less: Crosslinked structure index=(Equilibrium swelling capacity with respect to 0.9 wt % physiological saline solution1/3/(Weight average molecular weight (Mw) after hydrolysis treatment)×1000000; where the hydrolysis treatment leaves 50 mg of the water-absorbing resin as a solids content to stand still in 10 g of a 0.1 mol/l aqueous sodium hydroxide solution for 3 weeks at 80° C., and the weight average molecular weight (Mw) is measured after the treatment.

Abstract: Absorbing articles comprises water absorbing resin including a water-soluble unsaturated monomer, having a dissociable group, as a main component in a repeating unit of a main chain and an internal cross-linked structure, in which a cross-linked structure index represented by the formula [Cross-linked structure index=(Equilibrium swelling capacity with respect to 0.9% by weight of brine)1/3/(Weight average molecular weight after hydrolysis treatment)×1,000,000] is 14 or more, a weight average molecular weight after hydrolysis treatment is 220,000 or less, and a molecular weight distribution after hydrolysis treatment is 3.40 or less, and a method for producing the same.

Abstract: The present invention provides a novel acrylic acid crosslinked polymer and the use thereof. The present invention provides the acrylic acid crosslinked polymer in which the content of soluble components is 40 wt. % or higher. The present invention also provides a method for adjusting the viscosity of a fracturing fluid in a hydraulic fracturing method, the viscosity adjustment method including: A) a step of measuring the types and quantities of metal cations which are in water and which are the object of viscosity adjustment; B) a step of selecting the type and quantity of an acrylic acid crosslinked polymer on the basis of the types and quantities of metal cations and the pH so as to achieve a viscosity that is required for fracturing in a hydraulic fracturing method; and C) a step of adjusting the viscosity of the fracturing fluid using the acrylic acid crosslinked polymer of the selected type and quantity.

Abstract: Provided is a water-absorbing resin capable of having a high swollen gel elastic modulus while maintaining a high swelling capacity and a method for producing the same. The problem described above is solved by a water-absorbing resin including a water soluble unsaturated monomer having a dissociable group as a main component of a repeating unit of a main chain, wherein the water-absorbing resin has an internal crosslinked structure, a crosslinked structure index expressed by the following numerical formula 1 is 14 or more, a weight average molecular weight (Mw) of the water-absorbing resin after a hydrolysis treatment is 220,000 or less, and a molecular weight distribution (Mw/Mn) of the water-absorbing resin after a hydrolysis treatment is 3.40 or less: Crosslinked structure index=(Equilibrium swelling capacity with respect to 0.

Abstract: Absorbing articles comprises water absorbing resin including a water-soluble unsaturated monomer, having a dissociable group, as a main component in a repeating unit of a main chain and an internal cross-linked structure, in which a cross-linked structure index represented by the formula [Cross-linked structure index=(Equilibrium swelling capacity with respect to 0.9% by weight of brine)1/3/(Weight average molecular weight after hydrolysis treatment)×1,000,000] is 14 or more, a weight average molecular weight after hydrolysis treatment is 220,000 or less, and a molecular weight distribution after hydrolysis treatment is 3.40 or less, and a method for producing the same.