Production process for highly water absorbable polymer
US4525527A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 21, 1983 |
| Grant date | Jun 25, 1985 |
| Priority date | — |
| Expiry date | Jan 21, 2003 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/31855
- WIPO fieldMedical technology
- WIPO sectorInstruments
Abstract
Disclosed is a process for preparing water absorbing, cross-linked acrylate resins by aqueous polymerization of (A) acrylic acid neutralized 70 to 100 mole percent for example with ammonia, and/or caustic alkali and/or an amine; with (B) acrylamide in a mole ratio of 70 to 100 mole percent (A) to 30:0 mole percent (B); and (C) a water miscible or a water soluble polyvinyl monomer in an amount of 0.001 to 0.3 weight percent based on the total weight of (A) and (B). In accordance with one embodiment of the invention, the concentration of monomers (A) plus (B) should be at least 70 percent by weight of the polymerization mixture of (A) plus (B) plus (C) to achieve a substantially dry polymer (less than 15 weight percent water) when polymerization is completed by utilizing the exothermic heat of polymerization and cross-linking to drive off water without the need for additional heating to obtain a dry solid. The addition of polystyrene and/or methylcellulose substantially increases the water absorbing capacity of these polymers.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.