Nippon Shokubai Co., Ltd.

Eri Nagasawa

Kunihiko Ishizaki

Hiroyuki Ikeuchi

Satoshi Matsumoto

Shinichi Fujino

Hirotama Fujimaru

Masatoshi Nakamura

Makoto Nagasawa

Ryoko Tahara

A particulate water absorbing agent includes a polyacrylic acid and/or a salt thereof water absorbent resin as a main component, wherein the water absorbent resin includes &#x3b1;-hydroxycarboxylic acid and/or a salt thereof, and the absorbing agent satisfies a specific particle size distribution and a specific water absorbing performance, thereby solving the conventional problems. Further, a production method of the water absorbing agent is characterized in that &#x3b1;-hydroxycarboxylic acid and/or a salt thereof is added to (a) a monomer aqueous solution whose main component is acrylic acid and/or a salt thereof and which is being cross-linked and polymerized or (b) a hydrogel polymer after the polymerization. As a result, in the particulate water absorbing agent containing the water absorbent resin as a main component, it is possible to realize both excellent water absorbing performance and excellent coloring prevention effect. Further, it is possible to provide an absorbing article particulate water absorbing agent which is suitable for practical use.

Particulate water absorbing agent and production method thereof

The purpose of the present invention is to improve the water absorption of a water-absorbent resin without sacrificing the productivity, production cost, safety, and so on. Provided is a sustainable and renewable water-absorbent resin with excellent whiteness, which is suitable for mass consumption as disposal diapers or the like, and which can dispense with excessive purification of raw material acrylic acid. Also provided is a process for the production of a water-absorbent resin, which comprises: a step of preparing acrylic monomers; a step of polymerizing the monomers; and a step of drying the obtained aqueous gel, wherein the monomers at the time of polymerization contain at least 400 ppm of propionic acid.

Polyacrylic acid (salt) -based water-absorbent resin and a method for producing it

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Himeji, Japan

Eri Nagasawa