US3960770A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for preparing macroporous open-cell carbon foam from normally crystalline vinylidene chloride polymer
Assignee: Dow Chemical Co
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Filing: 1974-07-25
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Granted: 1976-06-01
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Expires: 1994-07-25
Abstract
Abstract Activated, macroporous open-cell carbon foam which is particularly useful as a filter for cigarette smoke and the like, is prepared by contacting, at a temperature of at least about 25°C a normally crystalline vinylidene chloride polymer in substantially open-cell, macroporous foam form with liquid ammonia until at least about 50 percent of theoretical Cl - is removed, then heating said foam to a temperature sufficient to remove residual ammonium chloride.
Inventors
- 👤 Charles F. Raley, Jr.
- 👤 Delman R. Asher
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 20:39
CPC Classifications
B; B01; B01D; B01D53/00; B01D53/02; A; A24; A24D; A24D3/00; A24D3/06; A24D3/08; C; C01; C01B; C01B32/00; C01B32/30; C01B32/354; C01B32/382
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
95 words
A process for preparing substantially open-cell, macroporous foamed activated carbon said process consisting essentially of (1) contacting, at a temperature of about 25°C. to about 100°C., a normally crystalline vinylidene chloride polymer in substantially open-cell, macroporous foam form with ammonia in liquid form as the sole reactant until at least about 50 percent of theoretical Cl - is removed, then (2) water extracting the reaction product of step (1) to recover a foamed activated carbon, and (3) heating said foamed activated carbon to a temperature up to about 350°C. sufficient to remove residual ammonium chloride.
Claim 2
Dependent Claim
95 words
A process for preparing substantially open-cell, macroporous foamed activated carbon said process consisting essentially of (1) contacting, at a temperature of about 25°C. to about 100°C., a normally crystalline vinylidene chloride polymer in substantially open-cell, macroporous foam form with ammonia in liquid form as the sole reactant until at least about 50 percent of theoretical Cl - is removed, then (2) water extracting the reaction product of step (1) to recover a foamed activated carbon, and (3) heating said foamed activated carbon to a temperature up to about 350°C. sufficient to remove residual ammonium chloride.
Claim 3
Dependent Claim
19 words
The process of claim 1 wherein said vinylidene chloride polymer is a copolymer of vinylidene chloride and vinyl chloride.
Claim 4
Dependent Claim
27 words
The process of claim 2 wherein said vinylidene chloride polymer is a copolymer of about 85 weight percent vinylidene chloride and about 15 weight percent vinyl chloride.
Claim 5
Dependent Claim
28 words
A substantially open-cell activated carbon foam wherein the average cell diameter is at least about 0.01 millimeter, said carbon foam being prepared by the process of Claim 1.
References Cited (Backward Citations)
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US3852429A
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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) | 1979-06-01 | 1979-12-01 | 1980-06-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-06-01 | 1983-12-01 | 1984-06-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-06-01 | 1987-12-01 | 1988-06-01 | $7700.00 | Window Closed / Lapsed |