Process for the production of water-adsorbing cellulose ethers
Abstract
Abstract This invention relates to an improvement in the process for the production of water-adsorbing, but at least partially water-insoluble, cellulose ethers in which cellulose is alkalized in a liquid reaction medium and etherified in a manner such that by etherification only an at least largely water-soluble carboxymethyl cellulose, carboxymethyl hydroxyethyl cellulose, hydroxyethyl cellulose or methyl hydroxyethyl cellulose is produced, and in which the cellulose is reacted in an alkaline reaction medium before, during, or after the etherification with a cross-linking agent which is polyfunctional towards cellulose and selected from the group consisting of acrylamido methylene chloroacetamide, dichloroacetic acid, phosphorous oxychloride, or a compound in which at least two groups functional towards cellulose are ##STR1## the improvement comprising effecting alkalization, etherification, and cross-linking in a liquid reaction medium other than isopropyl alcohol.
Inventors
- 👤 Arno Holst
- 👤 Helmut Lask
- 👤 Michael Kostrzewa
Bibliographic Details
Claims Analysis
Total Claims: 4References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1981-01-02 | 1981-07-04 | 1982-01-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-01-02 | 1985-07-04 | 1986-01-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-01-02 | 1989-07-04 | 1990-01-03 | $7700.00 | Window Closed / Lapsed |