US3619451A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Powdered cellulose ether
Assignee: Imperial Chemical Industries Ltd
•
Filing: 1968-09-19
•
Granted: 1971-11-09
•
Expires: 1988-09-19
Abstract
Abstract There is provided a method of preparing free-flowing cellulose ether comprising in press rolls a dried particulate partially gelled cellulose ether at a pressure in excess of 3 tons total load per linear foot of roll at a feed rate such as to give flakes with a thickness of 0.003-0.015 inches.
Inventors
- 👤 John Ernest Gill
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 15:09
CPC Classifications
C; C08; C08B; C08B11/00; C08B11/02; C08B11/04; C08B11/08; B; B24; B24C; B24C3/00; B24C3/08; B24C3/10; B24C3/14; C08B11/10; C08B11/12; C08B11/193; C08B11/20; C08B15/00; C08B15/10
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
24 words
A method as claimed in claim 1 wherein the feed rate is adjusted to give a flaked material having a thickness of 0.004-0.006 inches.
Claim 2
Dependent Claim
14 words
A method as claimed in claim 1 wherein the flaked material is subsequently pulverized.
Claim 3
Dependent Claim
35 words
A method as claimed in claim 1 wherein the cellulose ether is first partially gelled by treatment with a solvent, the degree of gelation being such as to fuse together the particles of cellulose ether.
Claim 4
Dependent Claim
30 words
A method as claimed in claim 4 wherein a water-soluble cellulose ether is treated with water in sufficient quantity to gel the surfaces of the particles and fuse them together.
Claim 5
Dependent Claim
18 words
A method as claimed in claim 4 wherein the cellulose ether is granulated and dried after partial gelation.
Claim 6
Dependent Claim
23 words
A method as claimed in claim 1 wherein the cellulose ether is treated with an aldehyde prior to pressing in the press rolls.
Claim 7
Dependent Claim
21 words
A method as claimed in claim 7 wherein the cellulose ether is treated with an aldehyde during the partial gelation step.
Claim 8
Dependent Claim
44 words
A method as claimed in claim 7 wherein a cellulose ether which is soluble in cold water but insoluble in hot water is allowed to cool while in the water-wet condition, giving partial gelation and the partially gelled product is sprayed with aqueous aldehyde.
Claim 9
Dependent Claim
56 words
A method as claimed in claim 7 comprising purifying a cellulose ether, which is soluble in or gelled by water but insoluble in water-miscible organic solvent, by water-miscible organic solvent washing and diluting the solvent, thereby wetting the cellulose ether with water to allow partial gelation to occur, and then spraying the ether with aqueous aldehyde.
Claim 10
Dependent Claim
23 words
A method as claimed in claim 7 wherein the cellulose ether is aldehyde treated after partial gelation, granulating and drying of the ether.
Claim 11
Dependent Claim
17 words
A method as claimed in claim 7 wherein the aldehyde used to treat the ether is glyoxal.
Claim 12
Dependent Claim
36 words
A method as claimed in claim 1 wherein the cellulose ether is selected from the group consisting of sodium carboxymethyl cellulose, methyl cellulose, ethyl methyl cellulose, hydroxyethyl methyl cellulose, ethyl hydroxyethyl cellulose and hydroxypropyl methyl cellulose.
References Cited (Backward Citations)
GB686116A
Cited
US2833758A
Cited
US2720464A
Cited
US2879268A
Cited
US3072635A
Cited
US3251824A
Cited
US3347847A
Cited
GB1080249A
Cited
US3453261A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-11-08 | 1975-05-10 | 1975-11-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-11-08 | 1979-05-10 | 1979-11-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-11-08 | 1983-05-10 | 1983-11-09 | $7700.00 | Window Closed / Lapsed |