Sanyo Chemical Industries, Ltd.

Hitoshi Takai

Kenji Tanaka

Keiji Tanaka

Takashi Sumiya

Masashi Date

Tsuyoshi Yuki

Shingo Mukaida

Satoshi Tamabuchi

Yoshiyuki Iwasaki

Daisuke Tagawa

An absorbent composition is produced by drying a mixture obtained by mixing a micro-filler (B) with a hydrogel having a water absorptive resin (A) and water. The hydrogel is produced by performing polymerization to produce the resin (A) and not drying the resin (A) after the polymerization. The absorbent composition has a specific surface area at least 10% lager than that of a reference composition produced by drying the hydrogel without the micro-filler (B).

Absorbent compositions, methods for producing thereof and absorbent products

The present invention relates to a process for producing water absorbent resin comprising a step of adding a high-molecular crosslinking agent which has at least 2 azetidinium salt groups in the molecule and has at least 1000 weight-average molecular weight to the water absorbent resin paticles having carboxylic groups and carboxylic acid salt groups and a step of efficiently crosslinking the vicinity of the surface of the water absorbent resin particles. In the process for producing water absorbent resin according to the present invention, the use of high-molecular crosslinking agent achieves less permeation of the crosslinking agent into the water absorbent resin particles and enables efficient crosslinking of the vicinity of the surface of the water absorbent resin particles. Consequently, the water absorbent resin having high water absorbency both under pressure-free state and under loading can be manufactured. Because the crosslinking agent contains a large amount of azetidinium salt groups highly reactive to carboxylic acid groups or carboxylic acid salt groups in the molecule, the water absorbent resin having high crosslinking efficiency, good safety, and good flowability can be manufactured.

Process for producing water absorbent resin

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Kyoto, Japan

Hitoshi Takai