Nippon Shokubai Co., Ltd.

Mai Sato

Ryota Wakabayashi

Yoshihiro Shobo

Shin-ya Katsube

Kunihiko Ishizaki

Motohiro Imura

Shin-Ichi Fujino

Tokio Shuto

Yoshifumi Adachi

Koji Honda

Tsuyoshi Yorino

Hiroyasu Watabe

Tomoyuki Arake

Naoki Katakura

Hiroki Hayashi

Satoshi Matsumoto

Masafumi Inoue

Sumito Kumagai

Masahumi Inoue

The present invention addresses the problem of providing; a water absorbent resin powder having a reduced amount of fine powder generated and a reduced amount of fine powder recovered; and a production method for the water absorbent resin. The production method of the present invention includes a drying step and a fine powder granulation step. The drying step is for obtaining a dried polymer by drying a particulate water-containing gel crosslinked polymer which is obtained using an acid group-containing unsaturated monomer as a main component. The fine powder granulation step is for obtaining a fine powder granulated product by adding a binder and an adhesion control agent to a fine powder made of a water absorbent resin. In this production method, the obtained fine powder granulated product is recovered in the drying step or in any step before the drying step.

Water-absorbent resin powder and production method thereof

A production method includes a surface-crosslinking step of heating a mixture of a surface-crosslinking agent and a particulate dried polymer obtained with an acid group-containing unsaturated monomer as a main component. A moisture content of the particulate dried polymer is not greater than 15% by mass. A heating device including a rotary container 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, is used in the surface-crosslinking step. The heating device includes a means for introducing and discharging a gas into and from the rotary container.

Method for producing water-absorbent resin particles

[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

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Himeji, Japan

Mai Sato