Patent US4478991A successfully refreshed from Google Patents.
US4478991A
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Sulfonic acid copolymer electrolyte
Assignee: Wyeth Holdings LLC
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Filing: 1982-04-14
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Granted: 1984-10-23
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Expires: 2002-04-14
Abstract
Abstract In electrochromic devices having a layer of electrochromic material, e.g. tungsten oxide, in contact with a polymeric electrolyte layer, the stability and speed of the device are improved by using a copolymer of 2-acrylamido-2-methylpropanesulfonic acid and vinyl sulfonic acid as the polymeric electrolyte.
Inventors
- 👤 Sun Y. Huang
- 👤 Robert D. Giglia
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 11:46
CPC Classifications
G; G02; G02F; G02F1/00; G02F1/01; G02F1/15; G02F1/1514; G02F1/1523; G02F1/1525
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
34 words
A water-soluble, transparent-film-forming copolymer of 2-acrylamido-2-methylpropane sulfonic acid (AMPS) and vinyl sulfonic acid (VSA) wherein the proportion of AMPS units to VSA units in the copolymer is in the range from 3:2 to 2:3.
Claim 2
Dependent Claim
34 words
A water-soluble, transparent-film-forming copolymer of 2-acrylamido-2-methylpropane sulfonic acid (AMPS) and vinyl sulfonic acid (VSA) wherein the proportion of AMPS units to VSA units in the copolymer is in the range from 3:2 to 2:3.
Claim 3
Dependent Claim
20 words
A copolymer defined by claim 1 wherein the proportion of AMPS units to VSA units in the copolymer is 1:1.
References Cited (Backward Citations)
US4296016A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-10-23 | 1988-04-23 | 1988-10-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-10-23 | 1992-04-23 | 1992-10-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-10-23 | 1996-04-23 | 1996-10-23 | $7700.00 | Window Closed / Lapsed |