Nippon Shokubai Co., Ltd.

Masafumi Inoue

Hideki Oishi

Shuji Shimizu

Kunihiko Ishizaki

Yoshifumi Adachi

Motohiro Imura

Shin-Ichi Fujino

Ryota Wakabayashi

Koji Honda

Yoshihiro Shobo

Mai Sato

Jiro Iriguchi

Shin-ya Katsube

Tsuyoshi Yorino

Tokio Shuto

Hiroyasu Watabe

Tomoyuki Arake

Hiroki Hayashi

Naoki Katakura

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

A grain aggregate is formed by bonding a plurality of cross-linking polymeric grains via a substance (binder) having a reactive functional group, and alternatively, the grain aggregate is formed by bonding at least two different types of a plurality of grains, thus providing the grain aggregate having the improved heat resistance, solvent resistance, strength and light-diffusing properties. Further, a light-diffusing agent made up of the grain aggregate has the improved light-diffusing properties. Therefore, when applying a light-diffusing mold article including the light-diffusing agent to, for example, a backlight of a liquid crystal display device, high brightness and a wide angle of visibility can be attained. Further, by spray drying of a dispersion liquid containing the grain aggregate, the grain aggregate can be produced with ease.

Grain aggregate and producing method thereof, and light-diffusing agent

A process for producing amino resin particles includes: a reaction process for obtaining a reaction solution containing an amino resin precursor which is obtained by a reaction of an amino compound with formaldehyde, and having a viscosity in a range of from 2&times;10 Pa&middot;s to 5.8&times;10 Pa&middot;s at a temperature in a range of from 95&deg; C. to 98&deg; C.; an emulsion process for obtaining an emulsion by emulsifying the reaction solution; and a curing process for curing the amino resin precursor in the emulsion state by adding a catalyst to the emulsion. With this producing process, it is possible to readily produce amino resin particles with an essentially uniform particle size (narrow particle size distribution). Further, with use of an aqueous dispersion of an inorganic pigment which is obtained by wet pulverizing the inorganic pigment in an aqueous medium until the average particle size of the inorganic pigment measured by a light scattering method becomes not more than 300 nm, it is possible to obtain amino resin particles with superior properties in coloring strength, visibility, heat resistance, solvent resistance, and chemicals resistance.

Process for producing amino resin particles

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Himeji, Japan

Masafumi Inoue