Method for producing particulate water-absorbing agent
US10537874B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Mar 30, 2016 |
| Grant date | Jan 21, 2020 |
| Priority date | — |
| Expiry date | Feb 4, 2037 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB01J2220/68
- WIPO fieldChemical engineering
- WIPO sectorChemistry
Abstract
Provided is a method for producing a particulate water absorbing agent, the method including the steps of: a polymerization step of polymerizing an acrylic acid (salt)-based aqueous monomer solution so as to obtain a crosslinked hydrogel polymer; a drying step of drying the crosslinked hydrogel polymer so as to obtain a dried polymer; a classification step of classifying a polymer subjected to classification so as to obtain a water-absorbing resin powder having a specific particle size; and a surface-crosslinking step of surface-crosslinking the water-absorbing resin powder that is not surface crosslinked, wherein the classification step is carried out at least either or both of before and/or after the surface-crosslinking step but after said drying step, and wherein a hole shape of a classification sieve used in the classification step is an irregular polygonal or non-circular.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.