Tobacco-smoke filters
Abstract
Abstract A tobacco-smoke filter comprises in admixture or close dispersion a first component which is a ready but weak or weakly retentive adsorbent for vapor-phase constituents, including aldehydes, of tobacco smoke, and a second component comprising amino groups, of which at least 30% are preferably primary groups, and being capable of chemically combining with said constituents to give substantially non-volatile reaction products. Suitably the first component may comprise a porous mineral earth, such as magnesium silicate or silica gel in porous granular form. The second component may comprise an ion-exchange resin or polyethylene imine. The second component may be carried upon a porous particulate material or carried or grafted upon a fibrous material or dispersed in a fibrous material carrying the second material in a dispersed condition. Alternatively, a mixture of granular first and second components may be dispersed in a fibrous or filamentary material or disposed between plugs of such material.
Inventors
- 👤 Henry G. Horsewell
- 👤 James W. P. Phelpstead
Bibliographic Details
Claims Analysis
Total Claims: 13References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1984-11-16 | 1985-05-18 | 1985-11-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-11-16 | 1989-05-18 | 1989-11-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-11-16 | 1993-05-18 | 1993-11-17 | $7700.00 | Window Closed / Lapsed |