Nippon Shokubai Co., Ltd.

Hiroyasu Watabe

Kunihiko Ishizaki

Motohiro Imura

Shin-Ichi Fujino

Ryota Wakabayashi

Koji Honda

Yoshihiro Shobo

Mai Sato

Tokio Shuto

Shin-ya Katsube

Yoshifumi Adachi

Tomoyuki Kuwamoto

Akio Naka

Hideo Asano

Hirokazu Niwa

Tsuyoshi Yorino

Masafumi Inoue

Tomoyuki Arake

Hiroki Hayashi

Naoki Katakura

Yoshiyuki Shiotani

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

The invention provides a retardation film, composed primarily of an acrylic polymer, with transparency, heat resistance, and large retardation. The retardation film of the present invention is composed primarily of an acrylic polymer. The film has an in-plane retardation of from 130 nm to 500 nm, inclusive, per 100 &#x3bc;m thickness at a wavelength of 589 nm. The film has a total light transmittance of not less than 85%. The retardation film has a glass transition temperature of preferably from 110&#xb0; C. to 200&#xb0; C., inclusive. The acrylic polymer, which is the primary component, preferably has a lactone ring structure.

Retardation film

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Suita, Japan

Hiroyasu Watabe