ABSORBENT RESIN AND METHOD FOR MANUFACTURING SAME

摘要

[Problem] To provide an absorbent resin capable of exhibiting high swollen gel elasticity while maintaining high swell capacity, and a method for manufacturing the absorbent resin. [Solution] The abovementioned problem is solved by a water-absorbent resin having an internal cross-linked structure and having as a main component of repeating units of a main chain thereof a water-soluble unsaturated monomer having a leaving group, the water-absorbent resin characterized in that the cross-linked structure index represented by equation 1 is 14 or greater, the weight-average molecular weight (Mw) after hydrolysis treatment is 220,000, and the molecular weight distribution (Mw/Mn) after hydrolysis treatment is 3.40 or less. Here, the hydrolysis treatment is a treatment in which 50 mg of the water-absorbent resin in terms of solid content is left at rest for three weeks in 10 g of an aqueous solution of sodium hydroxide having a concentration of 0.1 mol/L at 80°C, and the weight-average molecular weight (Mw) is a value measured after the abovementioned treatment. The water-absorbent resin is also manufactured by a method which includes, for example, a reaction step for reacting a first star polymer having the aforementioned water-soluble unsaturated monomer as a main component of repeating units of each branched chain thereof and having a first reactive functional group at the terminal end of each branched chain thereof with a second star polymer having the aforementioned water-soluble unsaturated monomer as a main component of repeating units of each branched chain thereof and having at the terminal end of each branched chain thereof a second reactive functional group capable of reacting with the first reactive functional group and forming a chemical bond therewith.