Nippon Shokubai Co., Ltd.

Tokio Shuto

Motohiro Imura

Ryota Wakabayashi

Shin-Ichi Fujino

Koji Honda

Yoshihiro Shobo

Mai Sato

Kunihiko Ishizaki

Shin-ya Katsube

Hiroyasu Watabe

Yoshifumi Adachi

Tsuyoshi Yorino

Tomoyuki Arake

Masafumi Inoue

Hiroki Hayashi

Naoki Katakura

[Object] To provide a method for efficiently producing a water-absorbing agent having excellent physical properties. [Solution] The method for producing a water-absorbing agent includes a drying step of drying a particulate crosslinked hydrogel polymer containing a drying aid. The drying aid is (a) a compound having a betaine structure and having a long-chain alkyl group having 8 or more carbon atoms, one quaternary nitrogen, and one acid group within a molecule thereof and/or (b) a compound having a long-chain alkyl group having 8 or more carbon atoms, one tertiary nitrogen, and one or more acid groups within a molecule thereof. An addition amount of the drying aid with respect to a gel solid content of the particulate crosslinked hydrogel polymer is 0.001% by mass to 0.5% by mass. In this production method, surface-crosslinking is performed on water-absorbent resin powder obtained through the drying step.

Method for producing water-absorbing agent

The production method includes a drying step of drying a particulate crosslinked hydrogel polymer obtained by polymerizing a monomer, which is a material of a water-absorbent resin, using a heating device to obtain dried particles. The heating device includes: a rotary container that contains the particulate crosslinked hydrogel polymer therein and rotates; and a plurality of heating tubes that are located within the rotary container, extend in an axial direction of the rotary container, and rotate together with the rotary container. A gel temperature of the particulate crosslinked hydrogel polymer to be subjected to the drying step, the gel temperature being measured by a contact thermometer, is not lower than 50&#xb0; C.

Method for producing water-absorbent resin powder, and drying device and drying method for particulate hydrous gel

The production method includes: a gel-crushing step of grinding a crosslinked hydrogel polymer to obtain a particulate crosslinked hydrogel polymer; a heating drying step of obtaining dried particles from the particulate crosslinked hydrogel polymer by using a continuous stirring drying machine; a post-crosslinking step of post-crosslinking the particulate crosslinked hydrogel polymer or the dried particles; and a sizing step of adjusting a particle size of the dried particles or the post-crosslinked dried particles to obtain water-absorbent resin powder. The particulate crosslinked hydrogel polymer contains a gel fluidizer. A gel temperature of the particulate crosslinked hydrogel polymer containing the gel fluidizer, the gel temperature being measured by a contact thermometer, is not lower than 50&#xb0; C. In the production method, the dried particles or the post-crosslinked dried particles is forcedly cooled before the sizing step.

Method for producing water-absorbent resin powder and production apparatus therefor

[Object] To provide a method for producing a water-absorbent resin in powder form or particle form, which has excellent physical properties such as water absorption performance and the like, at high productivity. [Solution] A method for producing a water-absorbent resin includes: a polymerization step of polymerizing a monomer, which is a raw material of the water-absorbent resin, to obtain a hydrous gel crosslinked polymer dispersed in an organic solvent; and a separation step of separating the organic solvent and the hydrous gel crosslinked polymer. The separation step includes transfer, compression, and discharge of the hydrous gel crosslinked polymer.

Method for producing water absorbent resin

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Suita, Japan

Tokio Shuto