Reduction of carbon monoxide in mainstream cigarette smoke
A smoking article filter is designed to reduce the amount of carbon dioxide (CO) and increase the ratio of total particulate material (TPM) to CO in mainstream cigarette smoke. The design includes a non-porous microcapillary tube centered axially within a low-density filter.
a. Field of the Disclosure
The present disclosure relates to a system, a method, and a device configured to reduce carbon monoxide (CO) in mainstream cigarette smoke, as well as for increasing the ratio of total particulate matter (TPM) to CO delivered by a smoking article.
b. Background Art
In 2005, the European Commission established maximal values for “tar”1 (10 mg), nicotine (1 mg), and carbon monoxide2 (CO; 10 mg) per cigarette or “10-1-10,” as measured by the International Organization for Standardization (ISO) method from 1 Jan. 2004. This requirement creates a target tar/CO ratio of 1.0 for commercial smoking products. This is part of a trend of lowering product yield for all smoke compounds delivered in the cigarette, which entails developing new cigarette designs to lower yields while maintaining product taste and acceptability. A common approach to reach these goals is to increase filter ventilation in filtered cigarettes. Other approaches entail the use of adsorbent materials in the filter to adsorb CO and other non-desirable smoke components. However, these technologies tend to impact taste and product acceptability, so alternative technologies to allow control of the tar/CO ratio can be beneficial to the smoking industry. 1 As used herein, the term “tar” means total particulate matter (TPM) of the mainstream smoke produced from a smoking article after subtracting water and nicotine. The terms will be used interchangeably hereinafter.2 Carbon monoxide is a gas inhaled during smoking It has been linked to increased rates of cardiovascular disease.
Prior art
According to an aspect of the disclosure, a smoking article filter is designed to reduce the amount of CO and increase the TPM/CO ratio in mainstream cigarette smoke. The design includes a non-porous microcapillary tube centered axially within a low-density filter.
In an embodiment, a smoking article comprises a tobacco column comprising a proximal end and a distal ignitable end, the tobacco column configured to generate products of combustion comprising at least one of tar and carbon monoxide; and a filter segment, comprising a proximal mouth end and a distal end coupled to the tobacco column, the filter segment further comprising a tubular filter structure surrounding a non-porous microcapillary tube, the microcapillary tube centered axially within the tubular filter structure; wherein smoke inhaled by a user at the proximal mouth end of the filter segment comprises a ratio of tar to carbon monoxide that is greater than or equal to 1.0.
In another embodiment, a filter segment for use in a smoking article comprises a tubular filter structure surrounding a non-porous microcapillary tube, the microcapillary tube centered axially within the tubular filter structure; wherein smoke inhaled by a user of the smoking article comprises a ratio of tar to carbon monoxide that is greater than or equal to 1.0.
In another embodiment, a method for reducing an amount of carbon monoxide in mainstream cigarette smoke, the method comprises: inserting a non-porous microcapillary tube axially into a filter segment of a cigarette; and controlling at least one of a diameter of the microcapillary tube, a density of the filter segment, and a degree of air ventilation of the filter segment.
Additional features, advantages, and embodiments of the disclosure may be set forth or apparent from consideration of the following detailed description, drawings, and claims. Moreover, it is to be understood that both the foregoing summary of the disclosure and the following detailed description are exemplary and intended to provide further explanation without limiting the scope of the disclosure as claimed.
The accompanying drawings, which are included to provide a further understanding of the disclosure, are incorporated in and constitute a part of this specification, illustrate embodiments of the disclosure and, together with the detailed description, serve to explain the principles of the disclosure. No attempt is made to show structural details of the disclosure in more detail than may be necessary for a fundamental understanding of the disclosure and the various ways in which it may be practiced. In the drawings:
The present disclosure is further described in the detailed description that follows.
DETAILED DESCRIPTION OF THE DISCLOSUREThe disclosure and the various features and advantageous details thereof are explained more fully with reference to the non-limiting embodiments and examples that are described and/or illustrated in the accompanying drawings and detailed in the following.
The present inventors have found that three factors—the diameter of the microcapillary 18, the density of the filter 14B (also referred to as “tow density”), and the degree of air dilution—can be used to control the TPM/CO ratio. In particular, the present inventors have discovered the following useful relationship:
TPM/CO=0.84−0.14*TT+0.25*TID+0.28*AV+0.36*TID*AV (1)
where
-
- TPM is wet total particulate matter in milligrams (mg) per cigarette;
- CO is the total amount of carbon monoxide (g) per cigarette;
- TT is the density of the cellulose acetate filter, which is controlled by varying the tow type and number of tow strands. (For example, higher density filters are formed from 42,000 2.6-denier filaments and lower density filters are formed from 39,000 5.0-denier filaments, respectively.)
- TID is the inner diameter or I.D. of the microcapillary inserted into the cellulose acetate filter; and
- AV is cigarette air dilution expressed as a percentage of air measured between lasered holes in the filter about 13.5 mm from the mouth end and the non-air-diluted cigarette controls.
This relationship was estimated with a coefficient of determination, adjusted R square, of 0.75.
The above equation (1) can be used to design smoking articles with lower CO delivery at equivalent tar levels of commercially available smoking articles. In addition, because mixing of the unfiltered and the filtered smoke stream occurs in the mouth of the smokers, a fuller impact of the tobacco taste is possible. As such, cigarette 10B with a filter designed according to equation (1) above can provide a fuller tobacco taste at lower overall tar delivery compared to a traditional filtered cigarette 10A.
The open pressure drop (OPD) of a cigarette is the perceived drop in pressure between a cigarette's mouth piece and ventilation hole. A maximal OPD is typically desirable. In attempting to increase the TMP/CO ratio and maximize the OPD, the present inventors have found that OPD can be described according to the following equation:
OPD=213+19*TT−20*TID−27*AV−(13.5*TID+3.3*AV*TT) where (2)
-
- TT is the density of the cellulose acetate filter
- TID is the inner diameter or I.D. of the microcapillary inserted into the cellulose acetate filter;
- AV is cigarette air dilution expressed as a percentage of air dilution measured between lasered holes in the filter about 13.5 mm from the mouth end and the non-air-diluted cigarette control; and
- OPD is the open cigarette pressure drop in millimeters (mm) of water.
This relationship was estimated with a coefficient of determination, adjusted R square, of 0.99. In addition, the closed pressure drop referred to inFIG. 2 is the pressure drop from the ignitable end of a cigarette to the mouth end measured using standard physical characterization equipment for cigarettes.
The table 20 in
Using equations (1) and (2) above, the present inventors developed the regression charts shown in
It should be noted that even though the regressions shown in
The present inventors have further found that the nicotine level delivered by cigarettes with filters designed to increase the TPM/CO ratio, as described above, is not significantly affected by the use of such filters. The tar-to-nicotine relationship is shown in
In addition, because the filter segments 14B illustrated in
A mouth end segment 26 can be made of plastic or other non-absorbent material, as shown in
The presently disclosed filter designs can include a plurality of filter segments to further modify the delivered smoke characteristics and alter the appearance of the filter mouth end.
Mouth end segments useful to the practice of this invention can be built in numerous configurations and designs. For example, mouth end segments can be built with cellulose acetate tow to conceal single or multiple microcapillaries. Mouth end segments can be used with e-cigarettes in addition to traditional tobacco cigarettes. Mouth end segments can also be built according to designs that functionalize the aerosol stream by proportionally mixing aerosol of different compositions which originate from single or multiple capillaries, as shown in
Additionally, mouth end segments can also be built according to designs that affect the smoking experience by controlling the aerosol direction and/or velocity exiting the mouth end, as shown in
Claims
1. A smoking article comprising a tobacco column comprising a proximal end and a distal ignitable end, the tobacco column configured to generate products of combustion comprising at least one of tar and carbon monoxide; and
- a filter segment, comprising a proximal mouth end and a distal end coupled to the tobacco column, the filter segment further comprising a tubular filter structure surrounding a non-porous microcapillary tube, the microcapillary tube centered axially within the tubular filter structure;
- wherein smoke inhaled by a user at the proximal mouth end of the filter segment comprises a ratio of tar to carbon monoxide that is greater than or equal to 1.0.
2. The smoking article of claim 1, wherein the filter segment further comprises at least one of the following: cellulose acetate, paper, and nylon fiber.
3. The smoking article of claim 1, wherein the microcapillary tube comprises at least one of the following: a polycarbonate or other polymeric resins, including polyethylene, polypropylene, nylon, paper, and cellulose acetate.
4. The smoking article of claim 1, wherein the smoke inhaled by the user further comprises a reduced amount of carbon monoxide as compared to smoke filtered by a solid filter of a standard cigarette.
5. The smoking article of claim 1, wherein the smoke inhaled by the user further comprises a reduced amount of carbon dioxide and a reduced amount of tar as compared to smoke filtered by a solid filter of a standard cigarette.
6. The smoking article of claim 1, wherein the ratio of tar to carbon monoxide is a function of at least one of the following: a diameter of the microcapillary tube, a density of the filter segment, and a degree of air ventilation of the filter segment.
7. The smoking article of claim 1, wherein the smoke inhaled by the user further comprises a consistent ratio of tar to nicotine as compared to smoke filtered by a solid filter of a standard cigarette.
8. The smoking article of claim 1, wherein the filter segment further comprises a heat reflective or heat absorbent material that coats or forms at least one of the microcapillary tube or the tubular filter structure.
9. The smoking article of claim 1, wherein the filter segment further comprises at least one of the following: a fragrance, an encapsulated fragrance, polymeric beads, or carbon beads.
10. The smoking article of claim 1, wherein a diameter of the microcapillary tube varies within the tubular filter structure.
11. The smoking article of claim 1, further comprising a mouth piece coupled to the proximal mouth end of the filter segment.
12. The smoking article of claim 11, wherein the mouth piece is configured to disperse smoke delivered in the user's mouth.
13. The smoking article of claim 11, wherein the mouth piece is configured to conceal the microcapillary tube.
14. The smoking article of claim 11, wherein the mouth piece comprises a pattern of inlets configured to control a direction or a velocity of aerosol exiting the mouth piece.
15. A filter segment for use in a smoking article, the filter segment comprising a tubular filter structure surrounding a non-porous microcapillary tube, the microcapillary tube centered axially within the tubular filter structure;
- wherein smoke inhaled by a user of the smoking article comprises a ratio of tar to carbon monoxide that is greater than or equal to 1.0.
16. The filter segment of claim 15, further comprising at least one of the following:
- cellulose acetate, paper, and nylon fiber.
17. The filter segment of claim 15, wherein the microcapillary tube comprises at least one of the following: a polycarbonate or other polymeric resins, including polyethylene, polypropylene, nylon, paper, and cellulose acetate.
18. The filter segment of claim 15, wherein the smoke inhaled by the user further comprises a reduced amount of carbon monoxide as compared to smoke filtered by a solid filter of a standard cigarette.
19. The filter segment of claim 15, wherein the smoke inhaled by the user further comprises a reduced amount of carbon dioxide and a reduced amount of tar as compared to smoke filtered by a solid filter of a standard cigarette.
20. The filter segment of claim 15, wherein the ratio of tar to carbon monoxide is a function of at least one of the following: a diameter of the microcapillary tube, a density of the filter segment, and a degree of air ventilation of the filter segment.
21. The filter segment of claim 15, wherein the smoke inhaled by the user further comprises a consistent ratio of tar to nicotine as compared to smoke filtered by a solid filter of a standard cigarette.
22. The filter segment of claim 15, further comprising a heat reflective or heat absorbent material that coats or forms at least one of the microcapillary tube or the tubular filter structure.
23. The filter segment of claim 15, further comprising at least one of the following: a fragrance, an encapsulated fragrance, polymeric beads, or carbon beads.
24. The filter segment of claim 15, wherein a diameter of the microcapillary tube varies within the tubular filter structure.
25. The filter segment of claim 15, further comprising a mouth piece coupled to the tubular filter structure.
26. The filter segment of claim 25, wherein the mouth piece is configured to disperse smoke delivered in the user's mouth.
27. The filter segment of claim 25, wherein the mouth piece is configured to conceal the microcapillary tube.
28. The filter segment of claim 25, wherein the mouth piece comprises a pattern of inlets configured to control a direction or a velocity of aerosol exiting the mouth piece.
29. A method for reducing an amount of carbon monoxide in mainstream cigarette smoke, the method comprising:
- inserting a non-porous microcapillary tube axially into a filter segment of a cigarette; and
- controlling at least one of a diameter of the microcapillary tube, a density of the filter segment, and a degree of air ventilation of the filter segment.
30. The method of claim 29, wherein smoke inhaled by a user of the cigarette comprises a ratio of tar to carbon monoxide that is greater than or equal to 1.0.
Type: Application
Filed: Dec 12, 2014
Publication Date: Jun 16, 2016
Inventors: Steven E. Brown (Oak Ridge, NC), Luis A. Sanchez (Greensboro, NC)
Application Number: 14/569,135