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:
Jul. 01, 2014
Filed:
Apr. 27, 2011
Yusuke Watanabe, Himeji, JP;
Kazushi Torii, Himeji, JP;
Kozo Nogi, Himeji, JP;
Kunihiko Ishizaki, Himeji, JP;
Reiko Nakatsuru, Himeji, JP;
Shigeru Sakamoto, Himeji, JP;
Yusuke Watanabe, Himeji, JP;
Kazushi Torii, Himeji, JP;
Kozo Nogi, Himeji, JP;
Kunihiko Ishizaki, Himeji, JP;
Reiko Nakatsuru, Himeji, JP;
Shigeru Sakamoto, Himeji, JP;
Nippon Shokubai, Co., Ltd., Osaka, JP;
Abstract
A water absorbent resin having less fine powder or powdery dust and a controlled particle size is provided, and the water absorption rate of the water absorbent resin is increased by a simple method at low cost, while maintaining or improving other physical properties such as liquid permeability. Disclosed is a method for producing a polyacrylic acid (salt)-type water absorbent resin powder, which includes, in sequence, a step of polymerizing an aqueous solution of acrylic acid (salt)-type monomer; a step of gel-crushing a gel of a water-containing gel-like crosslinked polymer during polymerization or after polymerization; a step of drying the water-containing gel-like crosslinked polymer; and a step of pulverizing and classifying the dried polymer, wherein water absorbent resin fine particles having a particle size of less than 150 μm or a hydrated-particles thereof is added to a step prior to the drying step, and in the drying step, hot air drying is carried out with a hot air having an average flow velocity of 1.0 to 3.0 [m/s], a dew point of 30° C. to 100° C., and a hot air temperature of 140° C. to 235° C.