Water absorbing agent and production method thereof

摘要

A water absorbing agent includes water absorbent resin particles which are obtained by polymerizing a water-soluble ethylenic unsaturated monomer and which internally include a cross-linked structure, wherein a pressurized void average radius index is 140 or more. As a result, it is possible to provide a water absorbing agent which essentially includes water absorbent resin particles and is suitable for use in a sanitary material. Specifically, it is possible to improve not only a performance for absorbing and retaining aqueous liquid without pressure or under pressure but also (i) a performance for quickly absorbing aqueous liquid with a great help of a performance of a fibrous material, (ii) a performance for dispersing the aqueous liquid after absorbing the aqueous liquid, and (iii) a performance for retaining the aqueous liquid after absorbing the aqueous liquid.

主权项

1. A water absorbing agent, comprising water absorbent resin particles which are obtained by polymerizing a water-soluble ethylenic unsaturated monomer and which internally include a cross-linked structure, wherein a pressurized void average radius index is 140 μm or more,
where the pressurized void average radius index is a swollen gel void radius (d50) corresponding to 50% of a cumulative void water content in a physiological saline water under a load of 2.07 kPa, and the water absorbent resin particles each have a spherical or substantially spherical shape and the water absorbing agent contains a pressurized void average radius index enhancing agent selected from the group consisting of a multivalent metal compound, inorganic fine particles and a polycation polymer compound.