Patent US4278978A successfully refreshed from Google Patents.
US4379772A
Expired / Lapsed
US
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Method for forming an electrode active layer or sheet
Assignee: Diamond Shamrock Chemicals Co
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Filing: 1980-10-31
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Granted: 1983-04-12
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Expires: 2000-10-31
Abstract
Abstract The present disclosure is directed to an electrode active layer or sheet containing from about 60 to about 85 wt. % active carbon in intimate admixture with 15 to 40 wt. % fibrillated PTFE. This electrode has improved strength and is capable of operation at high current density with resistance to mechanical failure due to blistering of the electrode, and to a process for producing same. The process is characterized by combining a dilute dispersion of smaller polytetrafluoroethylene particles with a suspension of catalyzed or uncatalyzed larger active carbon particles to discontinuously coat active carbon with PTFE; fibrillating same; comminuting said fibrillated PTFE/active carbon mix; and then rolling same into a self-sustaining, coherent sheet form. Alternatively, the sheet form can be provided by deposition of the heat treated polytetrafluoroethylenated active carbon on a filter paper or like medium.
Inventors
- 👤 Frank Solomon
- 👤 Charles Grun
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 15:44
CPC Classifications
C; C25; C25B; C25B11/00; C25B11/04; C25B11/042; C25B11/043; C25B11/051; H; H01; H01M; H01M4/00; H01M4/86; H01M4/8663; H01M4/8668; H01M4/88; H01M4/8817; H01M4/8821; H01M4/8875; H01M4/8878; H01M4/8882; H01M4/8896; H01M4/90; H01M4/92; H01M4/96; Y; Y02; Y02E; Y02E60/00; Y02E60/30; Y02E60/50; Y10; Y10S; Y10S264/00; Y10S264/47
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
95 words
A process for forming active layer or sheet comprising adding a dilute aqueous dispersion of polytetrafluoroethylene particles to an aqueous suspension of larger active carbon particles to discontinuously coat said active carbon particles with smaller polytetrafluoroethylene particles; fibrillating said discontinuously coated particles by shear blending at between about 15° C. and 75° C. to form an intimate mix of carbon particles having attenuated adherent polytetrafluoroethylene particles; chopping said intimate mix to yield a granular mix to reduce any compression of the intimate mix during shear blending and nonsinteringly forming said granular mix into a sheet.
Claim 2
Dependent Claim
95 words
A process for forming active layer or sheet comprising adding a dilute aqueous dispersion of polytetrafluoroethylene particles to an aqueous suspension of larger active carbon particles to discontinuously coat said active carbon particles with smaller polytetrafluoroethylene particles; fibrillating said discontinuously coated particles by shear blending at between about 15° C. and 75° C. to form an intimate mix of carbon particles having attenuated adherent polytetrafluoroethylene particles; chopping said intimate mix to yield a granular mix to reduce any compression of the intimate mix during shear blending and nonsinteringly forming said granular mix into a sheet.
Claim 3
Dependent Claim
23 words
A process as in claim 1 wherein said granular mix is formed by rolling at temperatures of from about 60° to 90° C.
Claim 4
Dependent Claim
22 words
A process as in claim 1 wherein said active carbon particles have a particle size ranging from about 1 to 30 microns.
Claim 5
Dependent Claim
35 words
A process as in claim 1 wherein a soluble or volatile particulate pore-forming agent is added to said suspension and blended therewith prior to fibrillating and the pore-forming agent is subsequently removes from the sheet.
Claim 6
Dependent Claim
20 words
A process as in claim 1 wherein said granular mix is formed by filtration upon a salt bed filter medium.
Claim 7
Dependent Claim
23 words
A process as in claim 1 wherein said granular mix contains from about 60 to 85 wt.% active carbon the remainder being polytetrafluoroethylene.
Claim 8
Dependent Claim
34 words
A process as in claim 1 wherein said active carbon particles have an ash content of less than about 4 wt.% and a B.E.T. surface area of about 1000 m 2 /g and higher.
Claim 9
Dependent Claim
25 words
A process as in claim 1 which includes depositing a precious metal catalyst on said active carbon particles before adding said dilute polytetrafluoroethylene dispersion thereto.
Claim 10
Dependent Claim
12 words
A process as in claim 8 wherein said precious metal is platinum.
Claim 11
Dependent Claim
12 words
A process as in claim 8 wherein said precious metal is silver.
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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) | 1986-04-11 | 1986-10-11 | 1987-04-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-04-11 | 1990-10-11 | 1991-04-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-04-11 | 1994-10-11 | 1995-04-12 | $7700.00 | Window Closed / Lapsed |