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US4062368A Expired / Lapsed US ⏱️ 0.0 years remaining

Tobacco-smoke filters

Assignee: Brown and Williamson Holdings Inc
•
Filing: 1975-06-19
•
Granted: 1977-12-13
•
Expires: 1995-06-19
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Abstract

Abstract According to the invention, a material for the filtration of tobacco smoke by reduction of vapor-phase constituents without adverse effect on the taste of the smoke comprises carbon particles of a size substantially within the range of 300 to 1700 micron, coated over their surfaces, individually and without being bonded together, with a barrier layer which has a thickness within the range of 5 x 10-4 to 0.5 micron and which is discontinuous in that it has a porosity within the range of 7,000 to 200,000 cm3/min/10 cm2 per 10 cm water gauge and a permeability for organic vapors contained in tobacco smoke such that it permits the passage of molecules within the size range 5 x 10-4 to 2 micron, the said layer being composed substantially of an organic non-nitrogen-containing polymeric material which is non-volatile, substantially non-water-soluble and non-toxic. The invention is further concerned with tobacco smoke filters comprising such coated carbon particles.

Inventors

  • 👤 Robin Arthur Crellin
  • 👤 Christopher Robert Jenkins
  • 👤 James William Percy Phelpstead

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-11-04 11:15
CPC Classifications
A; A24; A24D; A24D3/00; A24D3/06; A24D3/16; A24D3/163

Claims Analysis

Total Claims: 5
Claim 1
Independent Claim 184 words
A tobacco-smoke filter which reduces vapor-phase constituents in tobacco smoke without adversely affecting taste, said filter containing from 10 to 200 mg of a particulate material comprised of carbon particles having a size substantially within the range of 300 to 1700 micron, said particles being coated over their external and internal surfaces, individually and without being bonded together, with a discontinuous barrier layer consisting of an organic, nitrogen- free, non-volatile, non-toxic polymer which is substantially water insoluble under conditions of use, said barrier layer having: a. a thickness within the range of 5 × 10 -4 to 0.5 micron, b. a porosity within the range of 7,000 to 200,000 cm 3 /min/10 cm 2 per 10 cm water gauge, and c. a permeability to molecules within the range of 5 × 10 -4 to 2 microns, said barrier layer being present at a coating level within the range of 0.1% to 8%, said coating level being designated as the weight of the coated carbon less the weight of the uncoated carbon divided by the weight of the uncoated carbon and expressed as a percentage.
Claim 2
Dependent Claim 184 words
A tobacco-smoke filter which reduces vapor-phase constituents in tobacco smoke without adversely affecting taste, said filter containing from 10 to 200 mg of a particulate material comprised of carbon particles having a size substantially within the range of 300 to 1700 micron, said particles being coated over their external and internal surfaces, individually and without being bonded together, with a discontinuous barrier layer consisting of an organic, nitrogen- free, non-volatile, non-toxic polymer which is substantially water insoluble under conditions of use, said barrier layer having: a. a thickness within the range of 5 × 10 -4 to 0.5 micron, b. a porosity within the range of 7,000 to 200,000 cm 3 /min/10 cm 2 per 10 cm water gauge, and c. a permeability to molecules within the range of 5 × 10 -4 to 2 microns, said barrier layer being present at a coating level within the range of 0.1% to 8%, said coating level being designated as the weight of the coated carbon less the weight of the uncoated carbon divided by the weight of the uncoated carbon and expressed as a percentage.
Claim 3
Dependent Claim 19 words
A tobacco-smoke filter according to claim 1, wherein the polymeric material is a synthetic polymer of a vinyl compound.
Claim 4
Dependent Claim 23 words
A tobacco-smoke fitter according to claim 1, wherein the polymeric material is selected from the group consisting of polyhydroxyethylmethacrylate, polymethylmethacrylate and polymethacrylic acid.
Claim 5
Dependent Claim 14 words
A tobacco-smoke filter according to claim 1, wherein the polymeric material is polyvinyl acetate.

References Cited (Backward Citations)

US2297248A Cited
US2876133A Cited
US3117943A Cited
US3091550A Cited
US3256236A Cited
US3217715A Cited
US3544507A Cited
US3528433A Cited
US3652461A Cited
US3856745A Cited
US3894545A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1980-12-12 1981-06-13 1981-12-13 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1984-12-12 1985-06-13 1985-12-13 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 1988-12-12 1989-06-13 1989-12-13 $7700.00 Window Closed / Lapsed

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