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Patent US4309534A successfully refreshed from Google Patents.
US4309534A
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Renatured chitosan and process of making same
Assignee: DELAWARE A NOT FOR PROFIT CORP OF, University of
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Filing: 1979-02-15
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Granted: 1982-01-05
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Expires: 1999-02-15
Abstract
Abstract Renatured chitosan having an optical rotation in solution that is at least 20% more negative than that of untreated chitosan and the process of making same. The process for preparing such renatured chitosan is accomplished by aging a solution of chitosan in an aqueous acid at a pH of about 2.0 to 5.5. It is preferred to age the solution at room temperature for about 2 to 14 days until the optical activity shifts toward the negative by at least about 20%.
Inventors
- 👤 Paul R. Austin
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 11:26
CPC Classifications
C; C08; C08L; C08L5/00; C08L5/08; C08B; C08B37/00; C08B37/0006; C08B37/0024; C08B37/0027; C08B37/003
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
84 words
The process for preparing renatured chitosan having an optical rotation as measured in solution at least 20% more negative than that of untreated chitosan which comprises mixing chitosan at room temperature with an aqueous, organic acid at a pH of about 2.0-5.5 until substantially all of the chitosan has dissolved, and allowing the solution to stand at room temperature for about 2-14 days, until the optical activity shifts toward the negative by at least about 20% and thereafter recovering renatured chitosan from the solution.
Claim 2
Dependent Claim
84 words
The process for preparing renatured chitosan having an optical rotation as measured in solution at least 20% more negative than that of untreated chitosan which comprises mixing chitosan at room temperature with an aqueous, organic acid at a pH of about 2.0-5.5 until substantially all of the chitosan has dissolved, and allowing the solution to stand at room temperature for about 2-14 days, until the optical activity shifts toward the negative by at least about 20% and thereafter recovering renatured chitosan from the solution.
Claim 3
Dependent Claim
18 words
The process of claim 1 in which the solution has a pH in the range of about 2.3-4.9.
Claim 4
Dependent Claim
21 words
The process of claim 1 in which the acid is selected from the group consisting of acetic, glycollic and pyruvic acids.
Claim 5
Dependent Claim
18 words
The process of claim 1 in which the solution is neutralized with alkali to precipitate the renatured chitosan.
Claim 6
Dependent Claim
38 words
The process of claim 1 in which a material is added to the solution which is miscible with the acid solution but is a non-solvent for chitosan, thereby coagulating the chitosan in the form of a shaped article.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1985-01-04 | 1985-07-06 | 1986-01-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-01-04 | 1989-07-06 | 1990-01-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-01-04 | 1993-07-06 | 1994-01-05 | $7700.00 | Window Closed / Lapsed |