Method for producing a water-absorbent resin
US9132413B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jul 20, 2011 |
| Grant date | Sep 15, 2015 |
| Priority date | — |
| Expiry date | Nov 16, 2031 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC08F220/56
- WIPO fieldMacromolecular chemistry, polymers
- WIPO sectorChemistry
Abstract
A method for producing a water-absorbent resin comprising at least two stages of reversed-phase suspension polymerization, wherein the first stage of the at least two stages of reversed-phase suspension polymerization comprises the following steps of: (A) performing a primary dispersion by stirring to mix in the absence of surfactants an aqueous solution of a water-soluble ethylenically unsaturated monomer containing a hydrophilic polymeric dispersion agent with a petroleum hydrocarbon dispersion medium in which a hydrophobic polymeric dispersion agent dissolves or disperses; (B) further performing a secondary dispersion by adding a surfactant to the resultant dispersion liquid; and (C) performing a polymerization by using a water-soluble radical polymerization initiator to obtain a water-absorbent resin as particles in a hydrous gel state which disperse in the petroleum hydrocarbon dispersion medium, and a water-absorbent resin obtained by the method.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.