Cigarette filter

• US 5,360,023 A
• Filed: 06/12/1992
• Issued: 11/01/1994
• Est. Priority Date: 05/16/1988
• Status: Expired due to Term

• Current Assignee: R J Reynolds Tobacco Company (R. J. Reynolds Tobacco)
• Original Assignee: R J Reynolds Tobacco Company (R. J. Reynolds Tobacco)
• Inventors: Worrell, Gary W., Perfetti, Thomas A., Blakley, Richard L., Shelar, Gary R., Gentry, Jeffery S.
• Primary Examiner(s): BAHR, JENNIFER DOYLE
• Application Number:
  US07/898,111
• Time in Patent Office: 872 Days
• Field of Search: 131/331, 131/342, 131/341, 131/335, 131/339, 131/365, 55/16, 55/68, 55/74, 55/75, 55/98
• US Class Current: 131/331
• CPC Class Codes: A24B 15/14 made of tobacco and a binding agent not derived from tobacco
• CPC Class Codes: A24B 15/165 comprising as heat source a carbon fuel or an oxidized or thermally degraded carbonaceous fuel, e.g. carbohydrates, cellulosic material
• CPC Class Codes: A24B 15/24 by extraction; Tobacco extracts
• CPC Class Codes: A24D 1/00 Cigars; Cigarettes
• CPC Class Codes: A24D 1/02 with special covers
• CPC Class Codes: A24D 1/18 Selection of materials, other than tobacco, suitable for smoking
• CPC Class Codes: A24D 3/043 with ventilation means, e.g. air dilution A24D3/041 takes precedence
• CPC Class Codes: A24D 3/163 Carbon

Abstract

Cigarettes include a filter element which have a gathered web of paper incorporating a carbonaceous material. The paper is gathered so as to include a plurality of longitudinally extending channels, and the channels provide a cross-sectional void area of about 5 to about 30 percent of the filter element.

Claims

1. A cigarette comprising a tobacco rod connected to a filter element having two ends and a cross-sectional area, said filter element comprising at least first and second separately formed filter segments positioned in longitudinal abutting relation, said first filter segment having a mouth end and comprising a gathered web of a paper including a carbonaceous material, the paper being gathered so as to form a plurality of longitudinal channels each having a longitudinal axis, each channel being open from end to end of said first filter segment alone the longitudinal axis thereof, each channel further having a cross-sectional void area, the total cross-sectional void area of said open channels comprising more than about 5 percent of the cross-sectional area of the first filter segment such that at least some mainstream smoke from the tobacco rod passes through the open channels in the first filter segment, the cross-sectional area of the first filter segment being entirely filled with the carbonaceous paper material and said open channels, said second filter segment comprising a filamentary tow material abutting the mouth end of the first filter segment, said second filter segment having a draw resistance such that the cigarette has a total pressure drop of between about 50 to about 200 mm of water at 17.5 cc/sec. air

2. The cigarette of claim 1 wherein the first filter segment including the gathered web of paper including a carbonaceous material exhibits a pressure drop of less than 2 mm water pressure drop at 17.5 cc/sec air flow per 1 mm length of filter segment.

3. The cigarette of claim 1 wherein each channel has a cross-sectional void area of about 0.05 mm² to about 0.3 mm².

4. The cigarette of claim 1 wherein the filter segment is devoid of any channels having a cross-sectional void area of more than about 2 mm².

5. The cigarette of claim 1 wherein the filter element has a circumference of about 23 mm to about 25 mm, and the first filter segment includes about 100 to about 200 channels.

6. The cigarette of claim 1 wherein the filter element has a circumference of about 23 mm to about 25 mm, and the first filter segment includes about 45 to about 100 channels.

7. The cigarette of claim 1 wherein the paper includes more than about 20 weight percent carbonaceous material, based on the dry weight of the paper.

8. The cigarette of claim 1 wherein the paper includes more than about 30 weight percent carbonaceous material, based on the dry weight of the paper.

9. The cigarette of claim 1 or 6 wherein the paper is corrugated.

10. The cigarette of claim 1 wherein the carbonaceous material within the first filter segment is an amount of about 75 to about 250 mg.

11. The cigarette of claim 1 wherein the paper consists essentially of wood pulp and carbonaceous material.

12. The cigarette of claim 1 wherein the paper exhibits a tensile strength of at least about 800 g/in.

13. The cigarette of claim 1 wherein the paper exhibits an inherent porosity of about 50 to about 300 CORESTA units.

14. The cigarette of claim 3 or 4 wherein the filter element including the gathered web of paper including a carbonaceous material exhibits a pressure drop of less than 2 mm water pressure drop at 17.5 cc/sec air flow per 1 mm length of filter element having that paper.

15. The cigarette of claim 3 or 4 wherein the carbonaceous material within the first filter segment is an amount of about 75 mg to about 250 mg.

16. The cigarette of claim 3 or 4 wherein the paper includes more than about 30 weight percent carbonaceous material, based on the dry weight of the paper.

17. The cigarette of claim 3 or 4 wherein the carbonaceous material has a carbon content above about 90 weight percent.

18. The cigarette of claim 3 or 4 wherein the paper has a basis weight of about 35 g/m² to about 60 g/m².

19. The cigarette of claim 1, 2, 5 or 7 wherein the carbonaceous material has a carbon content about 90 weight percent.

20. The cigarette of claim 8 wherein the carbonaceous material with the paper is less than about 65 percent, based on the dry weight of the paper.

21. The cigarette of claim 1, 2, 3, 4, 5 or 7 wherein the carbonaceous material has the form of particles having a diameter of about 20 μ

m to about 100 μ

m.

22. The cigarette of claim 1, 2, 3, 4, 5 or 7 wherein the carbonaceous material has the form of particles having a diameter of about 30 μ

m to about 70 μ

m.

23. The cigarette of claim 1, 2, 3 or 4 wherein the filter element has a circumference of about 23 mm to about 25 mm, and the gathered web of paper is provided from a web having a width of about 5 inches to about 8.5 inches.

24. The cigarette of claim 1 or 2 wherein the paper has a basis weight of about 35 g/m² to about 60 g/m².

25. The cigarette of claim 1 or 3 wherein the total cross-sectional void area of the channels is about 10 to about 30 percent of the cross-sectional area of the first filter segment.

26. The cigarette of claim 1, 2 or 10 wherein the paper has a thickness of about 0.08 mm to about 0.2 mm.

27. The cigarette of claim 1, wherein the total cross-sectional void area is up to about 30 percent.

28. The cigarette of claim 1, wherein the longitudinal length of the first filter segment is 10-30 millimeters.

29. The cigarette of claim 1, wherein the web of gathered paper has a width of 3.5 to 11 inches.