Patent US4035457A successfully refreshed from Google Patents.
US4035457A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Nonbiodegradable polymers
Assignee: GELSUB Inc
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Filing: 1975-05-01
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Granted: 1977-07-12
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Expires: 1995-05-01
Abstract
Abstract A new composition, cellulose acetate-chlorobutyrate pyridinium salt, which has superior biodegradation resistance and polymer membrane forming characteristics and related compositions.
Inventors
- 👤 Robert E. Kesting
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 18:56
CPC Classifications
B; B01; B01D; B01D71/00; B01D71/06; B01D71/08; B01D71/12; B01D71/14; B01D71/18; B01D67/00; B01D67/0002; B01D67/0009; B01D67/0011; B01D67/00111; C; C08; C08B; C08B3/00; C08B3/16
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
82 words
The method of forming membranes comprising the steps of reacting cellulose acetate with an acyl chloride selected from the group consisting of chloro-acetyl chloride, β-chloropropionyl chloride, Γ-chloro-butyryl chloride and Γ-chlorovaleryl chloride and with a pyridinium based tertiary amine to form a cellulose acetate-chloroacylate quaternary ammonium salt, forming a membrane casting solution of the cellulose acetate-chloroacylate quaternary ammonium salt in a solvent therefor mixed with a non-solvent liquid therefor, and casting the solution to form an asymmetric membrane by the phase inversion process.
Claim 2
Independent Claim
82 words
The method of forming membranes comprising the steps of reacting cellulose acetate with an acyl chloride selected from the group consisting of chloro-acetyl chloride, β-chloropropionyl chloride, Γ-chloro-butyryl chloride and Γ-chlorovaleryl chloride and with a pyridinium based tertiary amine to form a cellulose acetate-chloroacylate quaternary ammonium salt, forming a membrane casting solution of the cellulose acetate-chloroacylate quaternary ammonium salt in a solvent therefor mixed with a non-solvent liquid therefor, and casting the solution to form an asymmetric membrane by the phase inversion process.
Claim 3
Dependent Claim
19 words
The method defined in claim 1 wherein the acyl chloride is Γ-chloro-butyryl chloride and the solvent comprises ethylene formal.
Claim 4
Independent Claim
63 words
The method of forming membranes comprising dissolving the quaternary ammonium salt of cellulose acetate-chloroacetate, cellulose acetate-chloropropionate, cellulose acetate-chlorobutyrate or cellulose acetate-chlorovalerate into a solution consisting essentially of a solvent for the salt and a non-solvent for the salt and casting the solution into a thin layer to form by the phase inversion process an integral biodegradation resistant cellulose based asymmetric microporous permselective membrane.
Claim 5
Independent Claim
63 words
The method of forming membranes comprising dissolving the quaternary ammonium salt of cellulose acetate-chloroacetate, cellulose acetate-chloropropionate, cellulose acetate-chlorobutyrate or cellulose acetate-chlorovalerate into a solution consisting essentially of a solvent for the salt and a non-solvent for the salt and casting the solution into a thin layer to form by the phase inversion process an integral biodegradation resistant cellulose based asymmetric microporous permselective membrane.
Claim 6
Dependent Claim
25 words
The method defined in claim 3 wherein the salt is a pyridinium based quaternary ammonium salt of cellulose acetate-chlorobutyrate and the solvent comprises ethylene formal.
Claim 7
Dependent Claim
8 words
The product of the process of claim 1.
Claim 8
Dependent Claim
8 words
The product of the process of claim 2.
Claim 9
Dependent Claim
8 words
The product of the process of claim 3.
Claim 10
Dependent Claim
8 words
The product of the process of claim 4.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-07-11 | 1981-01-10 | 1981-07-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-07-11 | 1985-01-10 | 1985-07-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-07-11 | 1989-01-10 | 1989-07-12 | $7700.00 | Window Closed / Lapsed |