초록 ▼

According to the present invention, the manufacturing method for the water absorbing resin involves the step of polymerizing a water-soluble unsaturated monomer, 0.06 of 5 mol % of which is composed of an internal crosslinking agent; and the step of drying a water-containing gel which has a thermall

According to the present invention, the manufacturing method for the water absorbing resin involves the step of polymerizing a water-soluble unsaturated monomer, 0.06 of 5 mol % of which is composed of an internal crosslinking agent; and the step of drying a water-containing gel which has a thermally decomposing radical initiator content index of 40 to 100 at 100 to 250° C. The water absorbing resin of the present invention contains a water-soluble unsaturated monomer as a repeat unit for a major chain, 90 mol % of the monomer being composed of an acrylic acid and/or salt thereof, the resin having an internal crosslinking structure and exhibiting a weight-average molecular weight Mw of 360,000 to 1,000,000 daltons and an intrinsic viscosity IV of 2.1 to 6.0 dL/g where the weight-average molecular weight Mw and the intrinsic viscosity IV are measured after treatment under set 2 of hydrolysis conditions.

대표청구항 ▼

1. A water absorbing resin, comprising a water-soluble unsaturated monomer as a repeat unit for a major chain, 90 mol % or more, based on the total monomers making up the resin, of an acrylic acid and/or salt thereof, the resin having an internal crosslinking structure and exhibiting a weight-averag

1. A water absorbing resin, comprising a water-soluble unsaturated monomer as a repeat unit for a major chain, 90 mol % or more, based on the total monomers making up the resin, of an acrylic acid and/or salt thereof, the resin having an internal crosslinking structure and exhibiting a weight-average molecular weight Mw of 360,000 to 1,000,000 daltons and an intrinsic viscosity IV of 2.1 to 6.0 dL/g where the weight-average molecular weight Mw and the intrinsic viscosity IV are measured after treatment under set 2 of hydrolysis conditions, in which treatment 20 mg of the water absorbing resin is left in 10 grams of a 0.1 mol/L aqueous solution of sodium hydroxide at 80° C. for 3 weeks, and the water absorbing resin regulates a thermally decomposing radical initiator content index for a water-containing gel to 40 to 100. 2. The water absorbing resin of claim 1, wherein the resin shows a molecular weight distribution Mw/Mn after the treatment of 2.0 to 3.0. 3. The water absorbing resin of claim 1, wherein the resin contains extractable polymer content which has a weight-average molecular weight Mw of 150,000 to 500,000 daltons. 4. The water absorbing resin of claim 1, wherein the resin contains extractable polymer content which has an intrinsic viscosity IV of 1.0 to 2.0 dL/g. 5. The water absorbing resin of claim 1, wherein the resin contains extractable polymer content which has a molecular weight distribution Mw/Mn of 2.0 to 3.0. 6. The water absorbing resin of claim 1, wherein: the water absorbing resin has a mass-average particle diameter D50 of 200 to 600 μm; the water absorbing resin contains 0 to 5 mass % particles of such sizes that the particles can pass through a sieve having a mesh opening size of 150 μm; and the water absorbing resin has such a particle size distribution with a logarithm standard deviation σζ of 0.20 to 0.50. 7. The water absorbing resin of claim 1, further containing an α-hydroxy carboxylic acid salt.