Preparation of rapidly dissolving/absorbing powders of hydrophilic/super absorbent (CO)polymers
US5994419A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 14, 1997 |
| Grant date | Nov 30, 1999 |
| Priority date | — |
| Expiry date | Nov 14, 2017 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC08F2/32
- WIPO fieldMacromolecular chemistry, polymers
- WIPO sectorChemistry
Abstract
Rapidly dissolving/absorbing free-flowing powders of hydrophilic/superabsorbent (co)polymers, having irregular nonspherical morphology and a particle size distribution ranging from 100 .mu.m to 800 .mu.m, are prepared by (a) phase inversion (co)polymerizing stirred admixture of (i) a hydrocarbonic solution of at least one surfactant having an HBL ranging from 8 to 12 and (ii) an aqueous solution of at least one hydrophilic unsaturated monomer, in the presence of an effective amount of a radical polymerization initiator and at a predetermined temperature of (co)polymerization, (b) next introducing into the medium of (co)polymerization, after (co)polymerization of the at least one hydrophilic unsaturated monomer, a second aqueous solution of at least one hydrophilic unsaturated monomer, (c) then (co)polymerizing the second aqueous solution, and (d) thence extracting the hydrocarbonic phase and water from the resulting (co)polymerizate and drying same, with the proviso (e) that the second aqueous monomer solution is introduced at a temperature of about the predetermined temperature of (co)polymerization and the volumetric ratio of aqueous phase to hydrocarbonic phase ranges from 0.6 t…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.