Patent US4075279A successfully refreshed from Google Patents.
US4075279A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for the manufacture of swellable cellulose ethers
Assignee: Hoechst AG
•
Filing: 1976-09-23
•
Granted: 1978-02-21
•
Expires: 1996-09-23
Abstract
Abstract This invention relates to an improvement in the process for the manufacture of water-absorbing, but largely water-insoluble cellulose ethers, wherein cellulose is etherified with a halogen fatty acid in an alkaline medium to which organic solvents may be added, to such an extent that without a further reaction a water-soluble cellulose ether would be produced, and wherein, prior to, during, or after etherification, a further reaction is carried out with a cross-linking agent which is polyfunctional towards cellulose in an alkaline reaction medium, the improvement comprising that chips of regenerated cellulose film are used as cellulose.
Inventors
- 👤 Arno Holst
- 👤 Michael Kostrzewa
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 01:44
CPC Classifications
C; C08; C08B; C08B15/00; C08B15/005
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
90 words
In the process for the manufacture of water-absorbing, but largely water-insoluble cellulose ethers, wherein cellulose is etherified with a halogen fatty acid in an alkaline medium to which organic solvents may be added, to such an extent that without a further reaction a water-soluble cellulose ether would be produced, and wherein, prior to, during, or after etherification, said further reaction is carried out with a cross-linking agent which is polyfunctional towards cellulose in an alkaline reaction medium, the improvement comprising that chips of regenerated cellulose film are used as cellulose.
Claim 2
Dependent Claim
90 words
In the process for the manufacture of water-absorbing, but largely water-insoluble cellulose ethers, wherein cellulose is etherified with a halogen fatty acid in an alkaline medium to which organic solvents may be added, to such an extent that without a further reaction a water-soluble cellulose ether would be produced, and wherein, prior to, during, or after etherification, said further reaction is carried out with a cross-linking agent which is polyfunctional towards cellulose in an alkaline reaction medium, the improvement comprising that chips of regenerated cellulose film are used as cellulose.
Claim 3
Dependent Claim
25 words
A process according to claim 1 in which the chips are of regenerated cellulose film coated with a nitro lacquer or a polyvinylidene chloride lacquer.
Claim 4
Dependent Claim
55 words
A process according to claim 1 in which the cross-linking agent is selected from the group consisting of epoxy compounds, halohydrins, epichlorohydrin, polychlorinated higher alcohols, divinyl sulfone, acid chlorides and those compounds in which the group which is polyfunctional towards cellulose is either the acrylamido group, the chloro azomethine group, or the allyloxy azomethine group.
References Cited (Backward Citations)
US2026865A
Cited
US2150205A
Cited
US3732867A
Cited
US3589364A
Cited
US3758457A
Cited
US3936441A
Cited
US3939836A
Cited
US3884907A
Cited
US3976074A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1981-02-20 | 1981-08-22 | 1982-02-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-02-20 | 1985-08-22 | 1986-02-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-02-20 | 1989-08-22 | 1990-02-21 | $7700.00 | Window Closed / Lapsed |