Nippon Shokubai Co., Ltd.

Eri Goto

Kunihiko Ishizaki

Katsuyuki Wada

Takumi Hatsuda

Koji Miyake

Hirotama Fujimaru

Kazuki Kimura

Atsushi Motoyama

A method of producing a water-absorbent resin of the present invention reduces amounts of a residual cross-linking agent and a residual surfactant, achieves high productivity, and improves physical properties of the resultant water-absorbent, such as absorption capacity, extractable polymer content, powder friction, and gel crushability. The method includes the steps of: polymerizing an aqueous monomer solution containing as a major component an acrylic acid monomer in the presence of a cross-linking agent; and drying the resultant polymer by heating, in which the cross-linking agent is a multifunctional (meth)acrylate cross-linking agent having polyethylene glycol structural units including a total of 6 to 200 ethylene oxide repeating units, and the aqueous monomer solution includes a mono(meth)acrylate compound having polyethylene glycol structural units in an amount of 0.1 to 30% by weight relative to an amount of the multifunctional (meth)acrylate cross-linking agent.

Method of producing polyacrylic acid (salt) water-absorbent resin

The present invention provides: a water-absorbing composition such that portions containing the water-absorbing composition in a high concentration exhibit excessive-liquid permeation buffering effects in absorbent articles comprising the water-absorbing composition and hydrophilic fibers; and a use of this water-absorbing composition. The water-absorbing composition comprises a water-absorbent resin and an excessive-liquid permeation buffer, wherein the water-absorbent resin is a product by a process including the step of further crosslinking the surface vicinity of a crosslinked polymer, and this water-absorbing composition is characterized by having a liquid permeation buffering index of not less than 0.4 and exhibiting an absorption capacity of not less than 25 g/g in absorbent structures under load, and further having an average particle diameter in the range of 200&tilde;600 &mgr;m, wherein the ratio of particles having particle diameters smaller than 106 &mgr;m in the water-absorbing composition is not more than 5 weight %. This water-absorbing composition is, for example, used for the absorbent articles comprising the water-absorbing composition and the hydrophilic fibers.

Water-absorbing composition and its use

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Hyogo, Japan

Eri Goto