Process for producing improved water absorbing resin and resin made by the same.

摘要

The invention relates to a process for producing improved water absorbing resin comprising the steps of treating water absorbing resin particles (A) with an aqueous solution of a water-soluble compound (B) and a crosslinking agent (C), reacting, and obtaining resin particles crosslinked in the surface vicinity; and a water absorbing resin obtained by this process possessing the absorption characteristics of an absorbency under a pressure-free state of 50 times or more to physiological saline solution, and an absorbency under the pressurized state of 30 times or more to physiological saline solution. The water-soluble compound (B) is at least one water-soluble compound selected from the group consisting of alkylene-oxide adducts of monofunctional alcohols (1), a monofunctional salts of organic acids (2), and lactams (3), and inert to (A) and (C); and the crosslinking agent (C) has two or more functional groups capable of reacting with (A). The obtained improved water absorbing resin possesses an excellent absorbing capacity whether under no pressure or under pressure, and does not form lumps when brought into contact with water. The initial absorption rate is superior, and the dry feeling of the gel after absorbing water is excellent. Therefore, it is used beneficially as a sanitary material, cold insulating material, water sealing materials, and many others.