Nippon Shokubai Co., Ltd.

Shigenori Kirimura

Nobuyuki Harada

Yoshifumi Adachi

Masatoshi Nakamura

Kazuhisa Hitomi

Yuji Yamamoto

The present invention provides a process in which no surfactant is used, or even if the surfactant is used the amount thereof is as small as possible, thus stably obtaining a suspension to carry out a crosslinking reaction. A production process for a crosslinked polymer particle, comprising the steps of: forming a suspension in which liquid drops of a first phase are dispersed in a second phase by stirring both phases in the presence of an inorganic particle, wherein the first phase includes a high-molecular compound and a crosslinking agent, and wherein the first phase and the second phase are insoluble in each other, and wherein the affinity of the inorganic particle for water is different from that of the high-molecular compound; and carrying out a crosslinking reaction. Furthermore, an approximately spherical crosslinked polymer particle, which is free from a surfactant.

Crosslinked polymer particle and its production process and use

The present invention has an object to provide a process for producing a water-absorbing agent which is excellent in the absorption capacities under no load and under a load with good balance and can display excellent absorption properties even if the weight percentage of a water-absorbent resin (resin concentration) is high when the water-absorbent resin is used for materials such as sanitary materials. The above object can be achieved by adding a vinyl compound or both the vinyl compound and a polyhydric alcohol to a water-absorbent resin and heating the resultant mixture.

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Himeji, Japan

Shigenori Kirimura