Method for producing polyacrylic acid (salt) type water absorbent resin powder
US8765906B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Apr 27, 2011 |
| Grant date | Jul 1, 2014 |
| Priority date | — |
| Expiry date | Apr 27, 2031 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC08J2333/02
- WIPO fieldMacromolecular chemistry, polymers
- WIPO sectorChemistry
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.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.