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. 09, 2017
Filed:
Aug. 01, 2013
Nippon Shokubai Co., Ltd., Hyogo, JP;
Makoto Matsumoto, Hyogo, JP;
Seiji Kato, Hyogo, JP;
Shinichi Fujino, Hyogo, JP;
Noboru Nabara, Hyogo, JP;
Ryuichi Otani, Hyogo, JP;
Yasuhiro Kawaguchi, Hyogo, JP;
Narimasa Okugawa, Hyogo, JP;
Kentaro Ichikawa, Hyogo, JP;
Makoto Eto, Hyogo, JP;
Nippon Shokubai Co. Ltd., Osaka, JP;
Abstract
Provided is a method for producing a polyacrylic acid (salt)-based water absorbent resin in which the physical properties (especially liquid permeability) are improved and maintained even in large scale production. The method for producing a polyacrylic acid (salt)-based water absorbent resin, which sequentially includes a polymerization step, in which a monomer aqueous solution having acrylic acid (salt) as a main component is polymerized, a drying step, in which a water-containing gel-like crosslinked polymer obtained in the polymerization step is dried, and a classification step, in which a polymer obtained in the drying step is classified, wherein a rocking-type sieve classification apparatus is used in the classification step, and the rocking-type sieve classification apparatus has a sieve net having a trajectory and a rotation speed in the following ranges; radial gradient R: from 5 to 40 mm, tangential gradient T: from 0.1 to 25 mm, eccentric gradient E: from 40 to 80 mm, and rotation speed F: from 60 to 600 rpm.