US5414079A
Expired / Lapsed
US
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Oxidized cellulose
Assignee: Biocontrol Inc
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Filing: 1993-08-03
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Granted: 1995-05-09
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Expires: 2013-08-03
Abstract
Abstract A method for making an oxidized cellulose product from a cellulose material is disclosed. The method involves oxidizing a cellulose material into an oxidized cellulose product, comprising treating the cellulose material with a hypochlorite solution having an active chlorine content of between about 4 and about 6%, at a pH exceeding 9.5 and at a temperature, and for a time, effective to convert the cellulose material into the oxidized cellulose product; filtering the oxidized cellulose product; and washing the oxidized cellulose product with an antichlor agent such as sodium thiosulfate to remove chlorine and to raise the oxidized cellulose product to a neutral pH. The oxidized cellulose product may be used to form films, dispersions, gels, as carriers, for pharmaceuticals, cosmetics and other products.
Inventors
- 👤 Gilbert S. Banker
- 👤 Vijay Kumar
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 02:05
CPC Classifications
A; A61; A61K; A61K8/00; A61K8/02; A61K8/04; A61K8/18; A61K8/72; A61K8/73; A61K8/731; A61Q; A61Q19/00; C; C08; C08B; C08B15/00; C08B15/02; A61Q17/00; A61Q17/04
Claims Analysis
Total Claims: 23
Claim 1
Independent Claim
82 words
A method of oxidizing a cellulose material into an oxidized cellulose product, comprising: treating the cellulose material with a hypochlorite solution having an active chlorine content of between about 4 and about 6%, at a pH exceeding 9.5 and at a temperature, and for a time, effective to convert the cellulose material into the oxidized cellulose product; filtering the oxidized cellulose product; and washing the oxidized cellulose product to remove chlorine and to raise the oxidized cellulose product to a neutral pH.
Claim 2
Independent Claim
82 words
A method of oxidizing a cellulose material into an oxidized cellulose product, comprising: treating the cellulose material with a hypochlorite solution having an active chlorine content of between about 4 and about 6%, at a pH exceeding 9.5 and at a temperature, and for a time, effective to convert the cellulose material into the oxidized cellulose product; filtering the oxidized cellulose product; and washing the oxidized cellulose product to remove chlorine and to raise the oxidized cellulose product to a neutral pH.
Claim 3
Dependent Claim
19 words
A method in accordance with claim 1 wherein the oxidized cellulose product is additionally rinsed with methanol or acetone.
Claim 4
Dependent Claim
22 words
A method in accordance with claim 2 wherein the oxidized cellulose product is washed with an antichlor agent to remove chlorine therefrom.
Claim 5
Dependent Claim
18 words
A method in accordance with claim 3 wherein the effective pH ranges from about 9.5 to about 14.
Claim 6
Dependent Claim
20 words
A method in accordance with claim 4 wherein the initial pH of the hypochlorite solution is about 13.5 to 14.
Claim 7
Dependent Claim
19 words
A method in accordance with claim 4 wherein the effective temperature ranges from about 25° to about 90° C.
Claim 8
Dependent Claim
19 words
A method in accordance with claim 4 wherein the effective temperature ranges from about 70° to about 80° C.
Claim 9
Dependent Claim
19 words
A method in accordance with claim 6, wherein the volume to volume ratio of cellulose solution is about 1:>5.
Claim 10
Dependent Claim
24 words
A method in accordance with claim 6, wherein the weight to volume ratio of cellulose to hypochlorite ranges from about 1:7.5 to about 1:15.
Claim 11
Dependent Claim
21 words
A method in accordance with claim 6 wherein the cellulose material is cotton linters, α-cellulose, wood cellulose, or purified wood cellulose.
Claim 12
Dependent Claim
20 words
A method in accordance with claim 10 wherein the pH of the reaction mixture exceeds 9.5 throughout the oxidation step.
Claim 13
Dependent Claim
14 words
A method in accordance with claim 3 wherein the antichlor agent is sodium thiosulfate.
Claim 14
Independent Claim
101 words
A method of oxidizing a cellulose material into an oxidized cellulose product, comprising: reacting the cellulose material with a hypochlorite solution having an active chlorine content of between about 4% and 6%, at a temperature ranging from about 60° C. to about 80° C., and a pH ranging from about 9.5 to about 14 for a period of time effective to convert the cellulose material into the oxidized cellulose product; isolating the oxidized cellulose product by filtration; washing the oxidized cellulose product in an aqueous solution of an antichlor agent; followed by rinsing the oxidized cellulose product with methanol or acetone.
Claim 15
Independent Claim
101 words
A method of oxidizing a cellulose material into an oxidized cellulose product, comprising: reacting the cellulose material with a hypochlorite solution having an active chlorine content of between about 4% and 6%, at a temperature ranging from about 60° C. to about 80° C., and a pH ranging from about 9.5 to about 14 for a period of time effective to convert the cellulose material into the oxidized cellulose product; isolating the oxidized cellulose product by filtration; washing the oxidized cellulose product in an aqueous solution of an antichlor agent; followed by rinsing the oxidized cellulose product with methanol or acetone.
Claim 16
Dependent Claim
20 words
A method in accordance with claim 13 wherein the pH of the reaction mixture exceeds 9.5 throughout the oxidation step.
Claim 17
Dependent Claim
21 words
A method in accordance with claim 13 wherein the cellulose material is cotton linters, α-cellulose, wood cellulose, or purified wood cellulose.
Claim 18
Dependent Claim
21 words
A method in accordance with claim 15, wherein the volume of hypochlorite is at least 5 times the weight of cellulose.
Claim 19
Dependent Claim
24 words
A method in accordance with claim 15, wherein the weight to volume ratio of cellulose to hypochlorite ranges from about 1:7.5 to about 1:15.
Claim 20
Dependent Claim
13 words
An oxidized cellulose product made in accordance with the process of claim 1.
Claim 21
Dependent Claim
13 words
An oxidized cellulose product made in accordance with the process of claim 4.
Claim 22
Dependent Claim
13 words
An oxidized cellulose product made in accordance with the process of claim 13.
Claim 23
Dependent Claim
13 words
An oxidized cellulose product made in accordance with the process of claim 15.
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| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 1998-05-08 | 1998-11-07 | 1999-05-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2002-05-08 | 2002-11-07 | 2003-05-09 | $3760.00 | Window Closed / Lapsed |
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