US4195649A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Tobacco smoke filter
Assignee: Japan Tobacco Inc
•
Filing: 1978-01-13
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Granted: 1980-04-01
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Expires: 1998-01-13
Abstract
Abstract A tobacco smoke filter capable of selectively removing irritating materials and unpleasant bitter components from tobacco smoke and containing as a filter element nitrogen-containing activated carbon fibers produced by oxidizing acrylonitrile polymer fibers and then activating the oxidized fibers.
Inventors
- 👤 Katsuichi Noguchi
- 👤 Kazuo Maeda
- 👤 Yuriko Anzai
- 👤 Minoru Hirai
- 👤 Kazuo Izumi
- 👤 Kenji Niijima
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 10:22
CPC Classifications
A; A24; A24D; A24D3/00; A24D3/06; A24D3/16; A24D3/163
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
36 words
A tobacco smoke filter containing, as a filter element, nitrogen-containing activated carbon fibers produced by oxidizing acrylonitrile polymeric fibers having an acrylonitrile content of more than about 60% and then activating the oxidized acrylonitrile polymeric fibers.
Claim 2
Dependent Claim
36 words
A tobacco smoke filter containing, as a filter element, nitrogen-containing activated carbon fibers produced by oxidizing acrylonitrile polymeric fibers having an acrylonitrile content of more than about 60% and then activating the oxidized acrylonitrile polymeric fibers.
Claim 3
Dependent Claim
39 words
The tobacco smoke filter according to claim 1, wherein the nitrogen-containing activated carbon fibers have a specific surface area of about 100 to about 1500 m 2 /g and a nitrogen content of about 2 to about 15 wt.%.
Claim 4
Dependent Claim
20 words
The tobacco smoke filter according to claim 1, wherein the nitrogen-containing activated carbon fibers are combined with other fibrous materials.
Claim 5
Dependent Claim
30 words
The tobacco smoke filter according to claim 1, wherein the filter comprises the nitrogen-containing activated carbon fibers and at least one of pulp, acetate fibers, rayon fibers and polypropylene fibers.
Claim 6
Dependent Claim
25 words
The tobacco smoke filter according to claim 1, consisting essentially of a paper produced from a pulp with which nitrogen-containing activated carbon fibers were blended.
Claim 7
Dependent Claim
32 words
The tobacco smoke filter according to claim 1, consisting essentially of a non-woven fabric comprising nitrogen-containing activated carbon fibers blended with at least one of acetate fibers, rayon fibers and polypropylene fibers.
Claim 8
Dependent Claim
25 words
The tobacco smoke filter according to claim 1, wherein the filter comprises a core of the nitrogen-containing activated carbon fibers concentrically surrounded by other fibers.
Claim 9
Dependent Claim
30 words
The tobacco smoke filter according to claim 1, wherein the filter comprises the nitrogen-containing activated carbon fibers in a cylindrical form combined with a filter tip made of other fibers.
Claim 10
Dependent Claim
40 words
The tobacco filter according to claim 1, wherein the filter comprises a non-woven fabric comprising nitrogen-containing activated carbon fibers inserted into a cylindrical filter made of other fibers at a right angle to the longitudinal direction of said cylindrical filter.
Claim 11
Dependent Claim
68 words
The tobacco smoke filter according to claim 1, wherein said nitrogen-containing activated carbon fibers are produced by oxidizing acrylonitrile polymeric fibers in an oxidizing atmosphere under tension at a temperature of about 200° to about 300° C. until the amount of bonded oxygen reaches about 50 to about 90% of the saturated amount of bonded oxygen and then activating said oxidized fibers to produce nitrogen-containing activated carbon fibers.
Claim 12
Dependent Claim
38 words
The tobacco smoke filter according to claim 10, wherein said tension is such that the shrinkage of said fibers at the temperature of oxidation is about 50 to about 90% of the free shrinkage ratio at that temperature.
Claim 13
Dependent Claim
22 words
A method of removing acidic materials from tobacco smoke comprising passing tobacco smoke through the tobacco smoke filter according to claim 1.
Claim 14
Dependent Claim
26 words
The tobacco smoke filter according to claim 1, wherein nitrogen is present in the fibers in an amount of about 4 to about 10 weight percent.
Claim 15
Dependent Claim
26 words
The tobacco smoke filter according to claim 1, wherein nitrogen is present in the fibers in an amount of about 2 to about 15 weight percent.
Claim 16
Dependent Claim
21 words
The process of claim 14, wherein activation is at a temperature within the range of about 700° to about 1,000° C.
Claim 17
Dependent Claim
20 words
The process of claim 15, wherein activation is for a period of from about 10 minutes to about 3 hours.
Claim 18
Dependent Claim
20 words
The process of claim 15, wherein activation is with NH 3 , CO 2 , steam or a mixture thereof.
Claim 19
Dependent Claim
22 words
The process of claim 17, wherein the nitrogen content of the activated carbon fibers is about 2 to about 15 weight percent.
Claim 20
Dependent Claim
22 words
The process of claim 17, wherein the nitrogen content of the activated carbon fibers is about 4 to about 10 weight percent.
Claim 21
Independent Claim
78 words
A method of producing a tobacco smoke filter comprising oxidizing acrylonitrile polymeric fibers having an acrylonitrile content of more than about 60% in an oxidizing atmosphere under tension at a temperature of about 200° to about 300° C. until the amount of bonded oxygen reaches about 50 to about 90% of the saturated amount of bonded oxygen, activating said oxidized fibers to produce nitrogen-containing activated carbon fibers, and shaping the nitrogen-containing activated carbon fibers into a tobacco filter.
Claim 22
Independent Claim
78 words
A method of producing a tobacco smoke filter comprising oxidizing acrylonitrile polymeric fibers having an acrylonitrile content of more than about 60% in an oxidizing atmosphere under tension at a temperature of about 200° to about 300° C. until the amount of bonded oxygen reaches about 50 to about 90% of the saturated amount of bonded oxygen, activating said oxidized fibers to produce nitrogen-containing activated carbon fibers, and shaping the nitrogen-containing activated carbon fibers into a tobacco filter.
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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) | 1983-04-01 | 1983-10-01 | 1984-04-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-04-01 | 1987-10-01 | 1988-04-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-04-01 | 1991-10-01 | 1992-04-01 | $7700.00 | Window Closed / Lapsed |