WO2010118122A1

WO2010118122A1 - Smoke filtration device and method

Info

Publication number: WO2010118122A1
Application number: PCT/US2010/030221
Authority: WO
Inventors: Akshay Navaladi; Bradley Kaanta; Aditya Jain
Original assignee: ORANJEWAY Inc
Current assignee: ORANJEWAY Inc
Priority date: 2009-04-08
Filing date: 2010-04-07
Publication date: 2010-10-14
Anticipated expiration: 2011-10-08

Abstract

The present invention is directed to a filter comprising PDMS or a derivative thereof. Also described is a smoking article comprising the filter of the present invention. The filter of the present invention can remove toxic gas components from mainstream tobacco smoke without reducing the level of nicotine.

Description

Smoke Filtration Device and Method

CROSS-REFERENCE TO RELATED PATENT APPLICATIONS

This application claims the benefit of U.S. Provisional Application No. 61/167,567, filed April 8, 2009, the entire teachings of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

Various toxic components are contained in the main-stream smoke puffed by a smoker in smoking cigarette. Although traditional cigarette filter materials, such as cellulose acetate tow, can effectively remove tar and fine particles, they cannot remove toxic gas components in the smoke. Therefore, a need for new filter material exists.

SUMMARY OF THE INVENTION

The present invention is directed to a filter for removing toxic materials from a gas stream. The filter comprises polydimethyl siloxane (PDMS) or a derivative thereof, wherein the filter is capable of substantially removing at least one toxic gas component from the gas stream.

The present invention is also directed to smoking articles comprising a filter described herein.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 depicts a cigarette having a tobacco rod and a filter of the present invention.

FIG. 2 depicts a filter of the present invention having PDMS strips in a center cavity of cellulose acetate filter material. FIG. 3 is depicts a specific filter of the present invention that is used in testing the efficiency of the filter for removing toxic gas components from a cigarette mainstream smoke.

FIG. 4 are graphs showing quantity of pollutants in cigarette mainstream smoke: a) filtered through the filter of the present invention; and b) unfiltered (i.e., filtered through traditional filter material, cellulose acetate).

FIG. 5 is a graph showing quantity of specific toxic components in cigarette mainstream smoke.

FIG. 6 depicts the apparatus used for testing the efficiency of the filter of the present invention for removing toxic gas components from cigarette mainstream smoke.

DETAILED DESCRIPTION OF THE INVENTION

It has now been found that polydimethyl siloxane or a derivate thereof can efficiently remove toxic gas components from a gas stream. The filter of the present invention can remove various toxic gas component from cigarette smoke without reducing the level of nicotine.

In one embodiment, the present invention is directed to a filter for removing toxic gas components from a gas stream, wherein the filter comprises PDMS or a derivative thereof. In one embodiment, the filter of the present invention is capable of substantially removing at least one gas component from the gas stream. In one embodiment, the gas stream is tobacco mainstream smoke. Alternatively, the gas stream is mainstream smoke from a smoking article.

As used herein, "substantially" removing at least one toxic gas component means removing at least 50% of the gas component from the gas stream. In one embodiment, the filter of the present invention is capable of removing at least 50%, 60%, 70%, 80%, 90%, 95%, 96%, 97%, 98%, 99%, 99.9%, or 100% by weight of at least one toxic gas component from the gas stream.

The term tobacco "mainstream" smoke includes the mixture of gases, vapors and particulates passing through a smoking mixture and issuing through the filter end, i.e., the smoke issuing or drawn from the mouth end of a smoking article for example during smoking of a cigarette. In one embodiment, the filter of the present invention is capable of substantially removing at least one toxic gas component from a gas stream, wherein the gas component is selected from the group consisting of acetaldehyde, acetone, acrolein, acrylonitrile, 1-aminonaphthalene, 2-aminonaphthalene, 3-aminobiphenyl, 4-aminobiphenyl, ammonia, benzene, benzo(a)pyrene, 1,3 -butadiene, butyraldehyde, carbon monoxide, catechol, chromium, m-cresol, p-cresol, o-cresol, crotonaldehyde, formaldehyde, hydrogen cyanide, hydroquinone, isoprene, metals (for example, nickel, selenium, arsenic, cadmium, lead, mercury), methyl ethyl ketone, nicotine, nitric oxide, nitrogen oxides, phenol, propionaldehyde, pyridine, quinoline, resorcinol, styrene, tobacco-specific nitrosamines, toluene, propene, proadiene, 1 ,3- butadiene, isoprene, cyclopentadiene, 1 ,3-cyclohexadiene, methyl cyclopentadiene, diacetyl, cyclopentanone, methyl furan, 2,5-dimethylfuran, hydrogen sulfide, carbonylsulfide, methyl mercaptan and 1-methylpyrrole. Alternatively, the toxic gas component is selected from the group consisting of benzene, benzo(a)pyrene, toluene, formaldehyde, 1 -aminonaphthalene, 2-aminonaphthalene, phenol, acetaldehyde, pyridine and arsenic.

In one embodiment, PDMS or a derivative thereof is incorporated into a filter. Any suitable filter design may be used, which includes, but is not limited to, a mono filter, a dual filter, a triple filter, a cavity filter, a recessed filter or a free-flow filter.

In one embodiment, PDMS or a derivative thereof is incorporated into a mono filter. Mono filters typically contain a variety of cellulose acetate tow or cellulose paper materials. Pure mono cellulose filters or paper filters offer good tar and nicotine retention, and are biodegradable. In one embodiment, PDMS or a derivative thereof is incorporated into a cavity of a mono filter. Particularly, PDMS or a derivative thereof is incorporated into a center cavity of a mono filter. Alternatively, PDMS or a derivative thereof can be mixed with cellulose acetate in the mono filter. In another alternative, the cellulose acetate tow or cellulose paper in the mono filter can be coated with PDMS or a derivative thereof. In one embodiment, the filter of the present invention is depicted in FIG. 2. FIG. 2 depicts a filter 20 having cellulose acetate filter material 21 wrapped within a filter paper 22. The filter 20 also have PDMS strips 23 located in the cylindrical- shaped center cavity of the cellulose acetate filter material 21. In another embodiment, PDMS or a derivative thereof is incorporated into a dual filter. Dual filters can comprise a cellulose acetate mouth side and a pure cellulose segment or cellulose acetate segment on the smoking material or tobacco side. The length and pressure drop of the two segments of the dual filter can be adjusted to provide optimal adsorption, while maintaining acceptable draw resistance. PDMS or a derivative thereof can be incorporated into cellulose acetate segment at either the mouth side or the tobacco side. In one embodiment, PDMS or a derivative thereof is incorporated into a cavity of cellulose acetate segment. Alternatively, PDMS or a derivative thereof can be mixed with cellulose acetate to form the filter segment at the mouth side and/or the tobacco side, Alternatively, PDMS or a derivative thereof is incorporated into a triple filter. Triple filters may have mouth and tobacco side segments, while the middle segment comprises PDMS or a derivative thereof.

In another alternative embodiment, PDMS or a derivative thereof is incorporated into a cavity filter. Cavity filters have two segments, for example, acetate-acetate, acetate-paper or paper-paper, separated by a cavity containing PDMS or a derivative thereof.

In another alternative embodiment, PDMS or a derivative thereof is incorporated into a recessed filter. Recessed filters have an open cavity on the mouth side and contain the PDMS or a derivative incorporated into the plug material.

In one embodiment, PDMS or a derivative thereof is incorporated into the filter as a shaped article, particles or powder. In a particular embodiment, PDMS or a derivate thereof is shaped as strips. Alternatively, fibers of PDMS or a derivative thereof is used in the filter of the present invention. In one embodiment, the filter of the present invention is a component of a smoking article. For example, the filter of the present invention is directly connected with the tobacco rod at one end of the tobacco rod. Alternatively, the filter of the present invention is not a component of a smoking article (i.e., a stand alone filter that can be used in conjunction with a smoking article).

In another embodiment, the filter of the present invention further comprises cellulose acetate tow, cellulose paper, mono cellulose, mono acetate or a combination thereof.

In one embodiment, the filters of the present invention maybe optionally ventilated, and/or comprise additional sorbents (such as charcoal, activated carbon and/or magnesium silicate), catalysts, flavorants or other additives for the cigarette filter. In another embodiment, the present invention is directed to a smoking article comprising a filter described herein. Examples of smoking articles include, but are not limited to, a cigarette, a pipe, a cigar and a non-traditional cigarette. Non- traditional cigarettes include, for example, cigarettes for electrical smoking systems as described in U.S. Patent Nos. 6,026,820; 5,988,176; 5,915,387; 5,692,526; 5,692,525; 5,666,976; and 5,499,636. In one embodiment, the smoking article is a cigarette.

As used herein, a PDMS derivative is a polymer represented by the following structural formula:

wherein:

R, Ri and R₂ are each independently alkyl, alkenyl, alkynyl, cycloalkyl, heterocycloalkyl, aryl or heteroaryl; and n is 0 or an integer from 1 to 10,000.

Exemplary PDMS derivatives include, but are not limited to, polydiphenylsiloxane, polydibenzylsiloxane, polydiethylenesiloxane, polyethylmethylsiloxane, hexamethyldisiloxane, hexamthylcyclotrisiloxane and the like. As used herein, "Alkyl" means a saturated aliphatic branched or straight- chain monovalent hydrocarbon radical having the specified number of carbon atoms. For example, "(C₁-C₆)alkyl" means a radical having from 1-6 carbon atoms in a linear or branched arrangement. "(C₁-C₆)alkyl" includes methyl, ethyl, propyl, butyl, pentyl, and hexyl. Also included within the definition of "alkyl" are those alkyl groups that are optionally substituted. Suitable subsitutions include, but are not limited to, -halogen, -OH, -CN, alkoxy, amino, cycloalkyl, aryl, heteroaryl, or aryloxy.

"Alkenyl" means branched or straight-chain monovalent hydrocarbon radical containing at least one double bond and having specified number of carbon atoms. Alkenyl may be mono or polyunsaturated, and may exist in the E or Z onfiguration. For example, "(C₂-C₆)alkenyl" means a radical having from 2-6 carbon atoms in a linear or branched arrangement.

"Alkynyl" means branched or straight-chain monovalent hydrocarbon radical containing at least one triple bond and having specified number of carbon atoms. For example, "(C₂-C₆)alkynyl" means a radical having from 2-6 carbon atoms in a linear or branched arrangement.

"Cycloalkyl" means a saturated aliphatic cyclic hydrocarbon radical having the specified number of carbon atoms. It can be monocyclic, bicyclic, polycyclic (e.g., tricyclic), fused, bridged, or spire For example, monocyclic (C₃- Cg)cycloalkyl means a radical having from 3-8 carbon atoms arranged in a monocyclic ring. Monocyclic (C₃-C₈)cycloalkyl includes but is not limited to cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl and cyclooctane.

"Heterocycloalkyl" means a saturated 4-12 membered ring containing 1 to 4 heteroatoms, which may be the same or different, selected from N, O or S and optionally containing one or more double bonds. It can be monocyclic, bicyclic, tricyclic, fused, bridged, or spiro.

"Aryl" means an aromatic monocyclic, or polycyclic hydrocarbon ring system. Aryl systems include, but limited to, phenyl, naphthalenyl, fluorenyl, indenyl, azulenyl, and anthracenyl. 'Ηeteroaryl" means a monovalent heteroaromatic monocyclic or polycylic ring radical. Heteroaryl rings are 5- and 6-membered aromatic heterocyclic rings containing 1 to 4 heteroatoms independently selected from N, O, and S, and include, but are not limited to furan, thiophene, pyrrole, imidazole, pyrazole, oxazole, isoxazole, thiazole, isothiazole, 1,2,3-triazole, 1,2,4-triazole, 1,3,4-oxadiazole, 1,2,5- thiadiazole, 1,2,5-thiadiazole 1 -oxide, 1,2,5-thiadiazole 1,1 -dioxide, 1,3,4- thiadiazole, pyridine, pyridine-N-oxide, pyrazine, pyrimidine, pyridazine, 1 ,2,4- triazine, 1,3,5-triazine, and tetrazole. Bicyclic heteroaryl rings are bicyclo[4.4.0] and bicydo[4,3.0] fused ring systems containing 1 to 4 heteroatoms independently selected from N, O, and S, and include indolizine, indole, isoindole, benzo[b]furan, benzo[b]thiophene, indazole, benzimidazole, benzthiazole, purine, 4H-quinolizine, quinoline, isoquinoline, cinnoline, phthalazine, quinazoline, quinoxaline, 1 ,8- naphthyridine, and pteridine.

EXEMPLIFICATION

The example described below compares the efficacy for removing toxic gas components between a filter of the present invention and a traditional filter. The "unfiltered cigarette" described herein refers to a cigarette that contains a traditional filter material, cellulose acetate plug. The "filtered cigarette" described herein refers to a cigarette that contains the filter of the present invention, particular as depicted in FIG. 3, in conjunction with the cellulose acetate plug.

Filter

The filter used in the testing described below is depicted in FIG. 3. Testing procedure

Collection of smoke samples:

1 ) Six 10ml vials were filled with 5ml of cyclohexane., the solvent by choice for dissolving organic compounds contained in cigarette smoke.

2) 3 vials (fl , f2, O) were designated for collecting smoke from filtered cigarettes and the remaining 3 vials (ufl, uf2, uf3) were designated for collecting smoke from unfiltered cigarettes. 3) For collecting filtered smoke samples, first vial fl with the cap removed, was positioned snugly inside a handheld vacuum cleaner (Dirt Devil Detailer, Manufacturer: Royal Appliance Mfg. Co.). A plastic tube was then taken and a filtered cigarette was inserted into one end of the plastic tubing. To the other end of the plastic tubing, was inserted a tapering pipette tip

(Manufacturer: Agilent). The entire plastic tube (with the cigarette on one end and the pipette tip on the other) was inserted through the spout of the vacuum cleaner such that the pipette tip extended into the cyclohexane solvent inside the vial contained within the vacuum cleaner and the filtered cigarette hung outside the vacuum cleaner. The apparatus for collecting the smoke sample is depicted in FIG. 6.

4) The cigarette was then lit and the vacuum cleaner was engaged to start drawing in the filtered smoke in order to bubble it through cyclohexane till the cigarette was exhausted. 5) This process was repeated for 4 more cigarettes, for a total of 5 cigarettes.

After 5 cigarettes, vial f1 was removed, capped and then substituted with vial f2 and subsequently f3, each vial containing smoke from S filtered cigarettes dissolved in cyclohexane.

The entire process was then repeated with unfiltered cigarettes and vials ufl , u£2 and u£3 with all other conditions remaining constant. Collection of smoke samples was performed at room temperature and atmospheric pressure.

A seventh vial with 5ml of cyclohexane was designated as control. With the vial positioned inside the vacuum cleaner, but with no cigarette attached to the end of the plastic tube, the vacuum was engaged with all other conditions remaining the same. The only difference between the control and the preceding six vials was the absence of a cigarette attached to the plastic tube in order to gauge the amount of pollutants present in the experimental setup alone.

An eighth vial with 5ml of cyclohexane was designated as the blank for the purpose of GC-MS analysis. Analysis of smoke samples:

The composition of the smoke collected within each of the six smoke containing vials was analyzed on a GC-MS machine (Agilent 6890N GC, Detector - Agilent 5973 MSD, Phenomenex Phase ZB-5, 30M (L) x 0.25 mm (i.d.) x 0.25 micron, Carrier gas - Helium) at Boston University's Chemical Instrumentation Center. The control and blank solutions were analyzed as well. Settings and experimental conditions are described in Table 1.

Analysis of GC-MS data: 1 ) The area under the peak for each compound found in each of the three smoke samples from filtered cigarettes was noted and divided by the area under the peak of nicotine. Since nicotine concentration is unchanged between filtered and unaltered smoke samples, nicotine served as the normalization factor in order to facilitate comparison of compound concentrations between filtered and unfiltered smoke samples.

2) The three normalized area values were then used to arrive at an average. This process was repeated till an average normalized area-under-the-peak value was obtained for each compound found in smoke samples from filtered cigarettes. 3) The same was repeated for smoke samples from unfiltered cigarettes and in the end, a normalized area-under-the-peak value was obtained for each compound found in smoke samples from unfiltered cigarettes. 4) No peaks other than that for cyclohexane were found in the blank cyclohexane vial, obviating the need for subtracting compound concentrations found in the blank sample from compound concentrations found in the six experimental samples. An extremely negligible number of peaks were found in the control sample, positively indicating that all compounds present in the experimental vials were from their respective cigarettes. 5) The two data sets (one data set containing normalized concentrations of compounds found in filtered smoke samples and the second data set containing normalized concentrations of compounds found in unfiltered smoke samples) were then compared to see which compounds found in smoke samples from unfiltered cigarettes were absent or present in a reduced or greater amount in smoke samples from filtered cigarettes. The resulting findings are listed in Tables 2 and 3 and shown in FIGs.4 and 5.

Table 1.

Table 2. Quantity of gas components detected from the filtered and unfiltered cigarette mainstream smoke.

Table 3. Quantity of specific toxic gas components in filtered and unfiltered cigarette mainstream smoke.

The chemical compounds that correspond to the peaks listed in Table 2 are described in Table 4 below: Table 4

As evidenced by the data described above, the filter of the present invention is significantly more efficient in removing various toxic gas components than the traditional filter, without reducing the amount of nicotine.

Claims

CLAIMSWHAT IS CLAIMED IS:

1. A filter for removing toxic gas components from a gas stream, wherein the filter comprises polydimethyl siloxane (PDMS) or a derivative thereof.

2. The filter of Claim 1 , wherein the filter is capable of substantially removing at least one toxic gas component from the gas stream.

3. The filter of Claim 1 , wherein the filter is capable of removing at least 50%, 60%, 70%, 80%, 90% or 99% of at least one gas component from the gas stream.

4. The filter of any one of Claims 1-3, wherein the gas stream is tobacco mainstream smoke.

5. The filter of Claim 4, wherein the filter is a mono filter, a dual filter, a triple filter, a cavity filter or a recessed filter.

6. The filter of any one of Claims 1 -5, wherein the filter is a component of a smoking article.

7. The filter of any one of Claims 1 -5, wherein the filter is not a component of a smoking article.

8. The filter of any one of Claims 1 -7, wherein the filter further comprises cellulose acetate tow, cellulose paper, mono cellulose, mono acetate or a combination thereof.

9. The filter of any one of Claims 1-8, wherein the toxic gas component is selected from the group consisting of benzene, benzo(a)pyrene, toluene, formaldehyde, 1-aminonaphthalene, 2-aminonaphthalene, phenol, acetaldehyde, pyridine and arsenic.

10. A smoking article comprising a filter of any one of Claims 1 -9.

11. The smoking article of Claim 10, wherein the smoking article is selected from a cigarette, a piper, a cigar and a non-traditional cigarette.