US4193897A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Contact lenses formed of mixtures of cellulose esters and ethylene/vinyl acetate copolymers
Assignee: Bayer AG
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Filing: 1979-02-21
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Granted: 1980-03-18
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Expires: 1999-02-21
Abstract
Abstract Contact lenses and scleral lenses formed of mixtures consisting essentially of (1) from 99 to 70% by weight of a cellulose ester of one or more aliphatic carboxylic acids, and (2) from 1 to 30% by weight of an ethylene/vinyl acetate copolymer containing from 30 to 98% by weight of incorporated vinyl acetate.
Inventors
- 👤 Frank Wingler
- 👤 Theobald Eicher
- 👤 Friedemann Muller
- 👤 Winfried Fischer
- 👤 Richard Prinz
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 04:21
CPC Classifications
C; C08; C08L; C08L1/00; C08L1/08; C08L1/10
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
61 words
A contact lens or scleral lens formed of a mixture consisting essentially of (1) from 99 to 70% by weight of a cellulose ester of at least one aliphatic carboxylic acid having 1 to 5 carbon atoms and (2) from 1 to 30% by weight of an ethylene/vinyl acetate copolymer containing from 30 to 98% by weight of incorporated vinyl acetate.
Claim 2
Dependent Claim
61 words
A contact lens or scleral lens formed of a mixture consisting essentially of (1) from 99 to 70% by weight of a cellulose ester of at least one aliphatic carboxylic acid having 1 to 5 carbon atoms and (2) from 1 to 30% by weight of an ethylene/vinyl acetate copolymer containing from 30 to 98% by weight of incorporated vinyl acetate.
Claim 3
Dependent Claim
27 words
The contact lens or scleral lens of claim 1 wherein (1) is a member selected from the group consisting of cellulose acetate, cellulose acetopropionate and cellulose acetobutyrate.
Claim 4
Dependent Claim
23 words
A contact lens of scleral lens of claim 1 wherein the vinyl acetate content of (2) is from 60 to 80% by weight.
Claim 5
Dependent Claim
16 words
A contact lens or scleral lens of claim 1 wherein (2) is at least partially hydrolyzed.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1983-03-18 | 1983-09-17 | 1984-03-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-03-18 | 1987-09-17 | 1988-03-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-03-18 | 1991-09-17 | 1992-03-18 | $7700.00 | Window Closed / Lapsed |