The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
May. 03, 2011
Filed:
Jul. 13, 2009
Hiroyuki Ikeuchi, Hyogo, JP;
Makoto Nagasawa, Nara, JP;
Hiroyuki Ikeuchi, Hyogo, JP;
Makoto Nagasawa, Nara, JP;
Nippon Shokubai Co., Ltd., Osaka, JP;
Abstract
An object of the present invention is to provide a method for producing a particulate water-absorbent polymer particle having remarkably improved long-term color stability, without an adverse effect (such as a delay in polymerization) on synthesis of the particulate water-absorbent polymer. The method includes the steps of polymerizing a monomer aqueous solution (B) containing (i) at least one type of monomer (A) that is capable of forming a particulate water-absorbent polymer by polymerization, (ii) at least one type of crosslinking agent, (iii) at least one type of polymerization initiator and (iv) an organophosphorus compound in an amount of not less than 1 but not more than 100 ppm by mass with respect to the monomer (A) so as to form a hydrogel polymer, and drying the hydrogel polymer. The method enables to provide an excellent particulate water-absorbent polymer that realizes (i) long-term color stability and improvement in urine tolerance and (ii) absorbing property, which are in such a trade-off relationship. In this way, the above object is attained.