Sumitomo Seika Chemicals Co., Ltd.

Maoki Hama

Kenta Kumazawa

Hideki Yokoyama

Hiroki Yabuguchi

Tetsuhiro Hinayama

Koji Takagi

Sho Isokawa

Provided are: a water-absorbent resin that has excellent heat resistance, even in a water-absorbed state; and a water-blocking material comprising the water-absorbent resin. The water-absorbent resin according to the present invention includes a crosslinked polymer of a water-soluble ethylenically unsaturated monomer, and has a gel-viscosity retention S of 0.5 or more as calculated by the following formula (I):

Water-absorbing resin and water-blocking material

Provided are a water-absorbent resin easily separable from a recyclable resource in recovering the recyclable resource, and an absorbent article containing an absorbent material containing the water-absorbent resin. The water-absorbent resin according to the present invention has such a structure that a polymer formed from a water-soluble ethylenically unsaturated monomer is crosslinked by using a post-crosslinking agent. The water-absorbent resin has (1) a water-retention capacity for physiological saline of 35 g/g or more, (2) a water-absorption capacity for physiological saline under a load of 4.14 kPa of 10 mL/g or more, (3) an initial gel viscosity of 3000 mPa&#xb7;s or more, and (4) a gel decomposition index of 0.60 or less: gel decomposition index=B/A wherein A represents an initial gel viscosity (mPa&#xb7;s), and B represents a gel viscosity after one day (mPa&#xb7;s).

Water-absorbent resin and absorbent article

The present invention provides a method for producing water-absorbent resin particles that has a low stirring load, and can produce water-absorbent resin particles having a particle diameter within a specific range, with high productivity. The method for producing water-absorbent resin particles comprises adding an ethylenically unsaturated monomer all at once to a hydrocarbon dispersion medium mixed with a surfactant to perform reversed phase suspension polymerization, wherein the reversed phase suspension polymerization is performed in one step, or two or more steps, the surfactant is at least one selected from the group consisting of polyoxyethylene alkyl ether phosphates, alkali metal salts of polyoxyethylene alkyl ether phosphates, and alkaline earth metal salts of polyoxyethylene alkyl ether phosphates, and the surfactant has an HLB of 9 to 15.

Process for producing water-absorbing resin particles

Provided are: a water-absorbent resin which, when used as an absorbent material, retains a high water-absorption performance, increases the diffusivity of a to-be-absorbed liquid and makes it possible to effectively decrease the amount of re-wet; and an absorbent article formed using an absorbent material including the water-absorbent resin. The water-absorbent resin according to the present invention is a water-absorbent resin obtained by polymerizing a water-soluble ethylenically monomer in the presence of an internal-crosslinking agent and thereafter post-crosslinking the polymer with a post-crosslinking agent, characterized in that when subjected to a liquid flow test, the water-absorbent resin has an effective absorbent material index (K) indicated by equation (I) of 250 or greater.Effective absorbent material index ()=[(the amount of liquid flow) (g)]&#xd7;[(artificial-urine absorption ratio) (g/g)]&#x2003;&#x2003;(I)

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Himeji, Japan

Maoki Hama