HK1020845B - Tobacco smoke filter for removing toxic compounds, smokable device and method of making a smokable device - Google Patents

Description

Cigarette filter for removing toxic compounds, tobacco product and preparation method

Cross reference to related applications

The present application, filed on 1996, 5/15, entitled cigarette filter for the removal of toxic compounds, is a continuation of the U.S. patent application No. 08/648,314; a cigarette filter with humectant on 13/10 in 1995, a continuation-in-part application of U.S. patent application No. 08/543,050; a cigarette filter with humectant on 12/13 of 1994, U.S. patent application No. 08/363,975, filed on 3/26 of 1996 as part of U.S. patent 5,501,238; both of which are issued 1993 on 11/1 and entitled cigarette filters containing humectant, U.S. patent application No. 08/002,951, a continuing application which has now been abandoned. The present invention is also a continuation-in-part application, filed on 19.12.1995 entitled cigarette filters containing microcapsules, patent Cooperation treaty application Serial No. PCT/US 95/16486; the latter is a continuation-in-part application of U.S. patent application No. 08/534,050, the contents of each of which are incorporated herein by reference.

Technical Field

The present invention relates to cigarette filters, and more particularly, to cigarette filters for removing toxic compounds.

Background

It is well known that tobacco smoke contains mutagenic and carcinogenic compounds that cause disease and death in smokers. Examples of such materials include Polycyclic Aromatic Hydrocarbons (PAH) and nitrosamines.

Polycyclic aromatic hydrocarbons produce toxicity by intercalating into DNA molecules. Nitrosamines are electrophilic alkylating agents with strong carcinogenicity. Nitrosamines are not present in fresh or green tobacco, nor are nitrosamines produced during combustion. But rather, forms nitrosamines from the reaction of free nitrate during the processing and storage of tobacco, or results from the metabolic activation of secondary amines present in tobacco after inhalation.

Efforts to reduce the entry of toxic and mutagenic compounds into smokers have included cigarette filters located between burning tobacco and the smoker. Conventional filters are made with or without activated carbon cellulose acetate. However, these conventional filters have only a partial effect in reducing the amount of toxic and mutagenic compounds that enter the smoker. Moreover, conventional filters have the further disadvantage of removing flavor compounds, thus reducing the acceptance of the smoker.

Therefore, there is a need for an improved filter for a cigarette that can greatly remove toxic and mutagenic compounds from the smoke of tobacco. Furthermore, there is a need for an improved filter which allows the passage of flavor compounds while largely removing toxic and mutagenic compounds from the smoke of tobacco. Such an improved filter should preferably be simple to manufacture, inexpensive, and convenient to use.

Disclosure of Invention

The object of the present invention is a cigarette filter that meets the above-mentioned needs. In one embodiment, the filter comprises a porous matrix with a humectant, such as sodium pyroglutamate, dispersed in the filter. The humectant absorbs moisture from the tobacco smoke and thus acts as a wet filter for the tobacco smoke during use.

In another embodiment, the invention is directed to a cigarette filter comprising a porous matrix containing a copper-containing porphyrin, or a copper-containing porphyrin and sodium pyroglutamate, dispersed in the filter. The invention further relates to a cigarette filter containing essentially copper-containing porphyrin dispersed therein.

In another embodiment, the object of the invention is a cigarette filter comprising a porous matrix containing non-liquid water and sodium pyroglutamate, or non-liquid water and microcapsules, or non-liquid water and porphyrins, or non-liquid water, microcapsules and porphyrins, these substances being dispersed in the filter. The invention further relates to a cigarette filter consisting essentially of a porous matrix containing non-liquid water and sodium pyroglutamate, or non-liquid water and microcapsules, or non-liquid water and porphyrins, or non-liquid water, sodium pyroglutamate and porphyrins, or non-liquid water, microcapsules and porphyrins, which are dispersed in the filter.

In another embodiment, the invention is directed to a cigarette filter comprising a porous matrix having microcapsules dispersed therein. The microcapsules comprise an inner core and a shell. The shell includes a wetting agent, preferably sodium pyroglutamate. The shell further preferably comprises methylcellulose. Preferred inner cores comprise chlorophyllin. The inner core further preferably comprises at least one vegetable oil.

The filter of the present invention may also include at least one surfactant or at least one substance that aids in the removal of toxic and mutagenic compounds from tobacco smoke.

The filter of the present invention may be supplied alone or with tobacco products having a body of tobacco, such as cigarettes, cigars or pipes.

According to another embodiment of the invention, there is provided a cigarette filter according to the invention affixed to a separate body of tobacco.

According to another embodiment of the present invention there is provided a method of filtering tobacco on a smoking article comprising the steps of, first, providing a smoking article comprising a tobacco smoke filter according to the present invention, wherein the filter is attached to a body of tobacco. The tobacco body is then ignited, causing smoke to pass through the tobacco body and into the filter. The flue gas is then passed through, thereby filtering the flue gas.

According to another embodiment of the invention, there is provided a method of manufacturing a smoking article comprising the steps of, first, providing a tobacco smoke filter according to the invention. The filter is then attached to the tobacco body.

Detailed Description

These and other features of the present invention will be more readily understood from the following description and appended claims.

According to one embodiment of the present invention, a tobacco smoke filter is provided. The filter may be provided with a cigarette or cigar or other tobacco product containing tobacco bodies. Preferably, the filter is secured to one end of the smoking article such that smoke generated from the tobacco passes through the filter before entering the smoker. The filter may also be supplied separately in a form suitable for attachment to a cigarette, cigar or other tobacco product.

The filter according to the invention has the advantage of removing a large part of the mutagenic and carcinogenic substances from tobacco smoke. The filter also maintains a satisfactory or improved cigarette taste, nicotine content and smoking characteristics. The filter design is acceptable to the user and is neither cumbersome nor attractive, as is the case with commercial filter designs, attached to the end of a prefabricated cigarette. In addition, filters according to the invention can be manufactured from low cost, safe and efficient materials and require only minor modifications to standard cigarette equipment.

According to one embodiment of the invention, the filter comprises a porous substrate. The porous substrate may be any non-toxic material suitable for use as a filter for tobacco products and for cooperating with other substances according to embodiments of the present invention. Such porous substrates include cellulosic fibers, e.g., cellulose acetate, cotton, wood pulp, and paper; as well as polyesters, polyolefins, ion exchange materials, and other materials as will be readily understood by those of skill in the art upon review of the following disclosure.

Filter containing humectant

According to one embodiment of the invention, the filter comprises at least one humectant, which may or may not contain other substances disclosed herein. The humectant is capable of absorbing moisture from tobacco smoke and releasing it into the porous matrix to effect warm filtration of the smoke passing through the filter. Among other advantages, the wet filter system according to the present invention facilitates the removal of particulate matter from tobacco smoke and can be integrated with tobacco-containing products.

The wetting agent can be any suitable wetting agent. For example, the wetting agent may be selected from the following: glycerin, sorbitol, propylene glycol, sodium lactate, calcium chloride, potassium phosphate, sodium pyrophosphate or polyphosphate, calcium citrate, calcium gluconate, potassium citrate, potassium gluconate, sodium tartrate, sodium potassium tartrate, and sodium glutamate.

In a preferred embodiment, the filter contains a humectant which is sodium pyroglutamate (also known as sodium 2-pyrrolidone-5-carboxylate, or NaPCA). Sodium pyroglutamate has the advantage of being non-toxic and effective in removing charged particles from tobacco smoke and acts as a humectant in the temperature range of tobacco smoke. Moreover, it is characterized by innocuity, stability, easy preparation and convenient use. Sodium pyroglutamate has the following structure:

the filter according to the invention is simple and inexpensive to manufacture. In one method of preparation, a solution containing a wetting agent, such as sodium pyroglutamate, is first prepared. The porous substrate is then wetted with the solution. The wetted substrate is then dried to disperse the remaining wetting agent on or within the porous substrate. In a preferred embodiment, the humectant is present in an amount of from about 5% to about 60% by dry weight of the filter.

These and other advantages of the present invention are illustrated by the following comparative examples.

Example 1

Comparison of effectiveness between conventional tobacco smoke filters, wet filtered tobacco smoke filters with sodium pyroglutamate, and commercially available wet filtered tobacco smoke filters

The relative effectiveness of three types of filters in removing tobacco tar was determined:

1) conventional cellulose acetate filters ("cellulose acetate");

2) the wet-filter tobacco smoke filter according to the invention with cellulose acetate and sodium pyroglutamate ('sodium pyroglutamate'), and

3) commercially available wet filtration tobacco smoke filters ("wet filters").

A cellulose acetate filter with sodium pyroglutamate was first prepared by removing the cellulose filter of a commercially available cigarette, the weight of the fibers being about 0.21 g. Then, about 0.5ml of 10% by weight sodium pyroglutamate solution was added to each filter and the filters were dried overnight at 60 ℃.

A conventional cellulose acetate filter and a cellulose acetate filter containing sodium pyroglutamate were weighed and the weighed filters were inserted into a 3.75cm (1.5 inch) long polycarbonate tube having an inner diameter equal to the outer diameter of a standard cigarette. A non-filter cigarette containing 0.85g of tobacco was inserted into the polycarbonate tube adjacent one end of the filter. The other end of the polycarbonate tube was connected to a tube connected to a suction pump. The assay was repeated twice for each filter. The wet filter used in this test was also attached to a non-filter cigarette containing 0.85g of tobacco and then to a tube connected to a suction pump.

The cigarette passed through the filter was lit and intermittently smoked, simulating the suction of the cigarette until only a 0.5 inch unburnt end of the cigarette remained, the filter was removed from the polycarbonate tube or wet filter, weighed and placed in 10ml of methanol to elute tar and other substances from the cigarette remaining on the filter. The absorbance (at a wavelength of 350 nm) of the ethanol extract of the filter is used to indicate the amount of tobacco components of the cigarette retained on the filter. The weight added to the filter during smoking was recorded. The test results are shown in table 1.

TABLE 1

Testing	Filter tip	350	Absorbance at nm	Weight gain
					1	Cellulose acetate filter tip	0.470	A.U	35mg
2	Cellulose acetate filter tip	0.381	A.U	30mg
					3	Pyroglutamic acid sodium filter tip	0.731	A.U	71mg
4	Pyroglutamic acid sodium filter tip	0.625	A.U	60mg
					5	Wet filter tip	0.540	A.U	*
6	Wet filter tip	0.560	A.U	*

^*The weight gain of the tobacco component absorbed on the wet filter cannot be determined because the wet filter actually loses weight due to water evaporation during smoking.

Based on the absorbance data, the filters according to one embodiment of the invention (tables 3 and 4) were more effective than the conventional cellulose acetate filters without humectant (test 1 and test 2) and also more effective than the wet filters (tables 5 and 6).

Filter tip with non-liquid water

According to one embodiment of the present invention, there is provided a filter for wet filtering tobacco smoke, comprising "non-liquid water", with or without other substances disclosed herein. The non-liquid water is the mixture of methylated silica gel and water. In one embodiment, the weight percent of methylated silica gel is from 5 to 40% and the weight percent of water is from 60 to 95%. In a preferred embodiment, the methylated silica gel is 10% by weight and the water is 90% by weight. Preferably, non-liquid water is used as the filter of the present invention with good stability. Moreover, the non-liquid water is cheap, non-toxic and non-polluting to the environment.

In a preferred embodiment, the non-liquid water is present in an amount of from 1% to 20% by weight of the filter, and in a particularly preferred embodiment, the non-liquid water is present in an amount of from 5% to 10% by weight of the filter.

The non-liquid water used in the present invention can be prepared, for example, by the following method: excess water was shaken with methylated silica gel in a closed vessel until an equilibrium latex was obtained. The excess water was decanted and 10% of drying agent, relative to the amount of methylated silica, such as: underivatized silica gel. The latex was further shaken to disperse the drying agent.

One problem with using non-liquid water in tobacco smoke filters is: as a continuous layer is formed between the tobacco and the smoker, non-liquid water tends to clog the filter, thereby increasing resistance to airflow and reducing smoking comfort. To overcome this problem, an embodiment of the invention is provided in which non-liquid water is mixed with a loose fibrous material, the additional fibrous material providing a bridge construction to reduce the impact of the silica gel particles on the filter material when the smoker takes a puff on the cigarette. Examples of such materials include: cellulose and cellulose acetate, which are short enough in length that the non-liquid water behaves as a flowable powder. In a preferred embodiment, the fibres are less than about 1mm in length, and in a preferred embodiment, the tobacco smoke filter according to the invention comprises a porphyrin as discussed herein in addition to non-liquid water. For example: tobacco smoke filters according to the invention comprise a segment of about 1/8 and 1/4 inches and the distal end of the filter is filled with non-liquid water, chlorophyllin and cellulose within the filter, or between conventional filter material and tobacco. In such filters, tobacco smoke passes through the non-liquid water and porphyrin, and carcinogenic smoke constituents are retained in the non-liquid water and porphyrin layer.

The tobacco smoke filter according to this aspect of the invention may be prepared as follows: the non-liquid water and porphyrin mixture is added during the manufacture of the filter, or the mixture is injected into the filter or onto the interface between the tobacco and a conventional filter. The non-liquid water and porphyrin mixture may be injected through the axial end of the filter or through the side of the tobacco product, such as: through a mouthpiece attached to the injection device. Preferably, the injection device determines the amount of material injected per shot.

Alternatively, non-liquid water and porphyrin may be included in the filter extension for attachment to a conventional tobacco product, such as: standard cigarettes, or attached to cigarette filters by smokers. The extended portion of the filter comprises a non-liquid aqueous layer and a porphyrin layer, preferably a fibrous material as a substrate. The filter extension further includes a sleeve extending axially to mate with the proximal-most end of the tobacco product. The sleeve is held by a porous clamp to retain the non-liquid water and porphyrin on the filter extension. Preferably, the sleeve further comprises a length of conventional filter material such that, once attached to the tobacco product, the filter extension and the tobacco product behave in effect as a conventional tobacco product.

Filter tip with copper-containing porphyrin

According to another embodiment of the invention, there is provided a cigarette filter comprising at least one porphyrin, such as: chlorophyllin, with or without other substances disclosed herein. Preferably, the porphyrin is a copper-containing porphyrin such as: chlorophyllin and copper phthalocyanine trisulfonates (copper phthalocyanine ).

Porphyrins are planar compounds that inactivate several mutagenic and carcinogenic agents. Porphyrins inactivate planar mutagenesis and carcinogens primarily by incorporating the carcinogen into the planar porphyrin structure through hydrophobic interactions. Thus, porphyrins ideally need to be maintained in a liquid environment for the most efficient absorption of these tobacco carcinogens. Porphyrins further inactivate carcinogens by pi-pi bonding to Polycyclic Aromatic Hydrocarbons (PAHs). Copper-containing porphyrins also inactivate a wide variety of non-planar mutagens and carcinogens, including certain nitrosamines, by interaction with copper ions. Although known to inactivate various carcinogens, it is not known how to effectively use porphyrins in tobacco smoke filters.

Chlorophyllin is a natural copper-containing porphyrin and is the steady state form of chlorophyll, in which the magnesium in chlorophyll is replaced by copper. The formula of chlorophyllin is as follows:

however, chlorophyllin is difficult to chemically attach to tobacco smoke filter components. Thus, in a preferred embodiment, the copper-containing porphyrin that is mixed with the tobacco smoke filter is copper phthalocyanine. Copper phthalocyanine is a non-toxic synthetic chlorophyllin analog that is more easily attached to tobacco smoke filter components than chlorophyllin. The formula of copper phthalocyanine is as follows:

copper phthalocyanine is incorporated into a tobacco smoke filter by directly adding the copper phthalocyanine to the tobacco smoke filter. In a preferred embodiment, the copper phthalocyanine is incorporated into a tobacco smoke filter as a covalent bond ligand to cotton, such as "blue cotton", to viscose, such as "blue viscose", or other suitable material. In another preferred embodiment, the copper phthalocyanine may be added to a tobacco smoke filter in combination with other tobacco smoke filters of embodiments of the present invention. Copper phthalocyanine is attached to cellulose fibers in the form of an active reagent called c.i. reactive Blue 21, as described in the following references: hayatsu, Journal of Chromatography, 597: 37-56(1992), under mild conditions, form a stable ether linkage with free hydroxyl groups on cellulose fibers or other materials (unlike chlorophyllins and porphyrins).

In a preferred embodiment, the copper phthalocyanine is present in an amount of 0.1 to 5% by dry weight of the filter, whether free or covalently bonded. In a particular embodiment, the copper phthalocyanine is present in an amount of 1 to 3% of the dry weight of the filter.

Example II

Determination of the carcinogen-removing Capacity of cigarette filters comprising copper Phthalocyanine conjugated to a cellulose matrix

According to one embodiment of the present invention, cigarette filters comprising copper phthalocyanine conjugated to a cellulosic substrate were tested experimentally for their carcinogen removing ability. A standard cigarette filter comprises about 0.14g of cellulose acetate. According to one embodiment of the invention, the cigarette filter is identical to a standard filter, made of 0.14g of "blue cotton", copper phthalocyanine cellulose (catalog # 2029, Sigma, st. louis, MO) and attached to a cigarette (wanbao road). A control cigarette with the original cellulose acetate filter was also used in this experiment.

Two types of cigarettes are smoked simultaneously using a suction pump. The filters were removed and extracted with 1% ammonium hydroxide, respectively. 25 μ l of the filter extract was subjected to HPLC analysis using a Waters C18 reverse phase analytical column, eluted with 70% acetonitrile in water at a flow rate of 1ml/min, according to the knowledge of the skilled person. Detection was performed using UV absorption at 254 nm.

According to one embodiment of the invention, the average total peak area of the filter containing copper phthalocyanine is 7.81X 107. mu.V-sec. The average total peak area of the control filter without copper phthalocyanine was 4.34X 107. mu.V-sec. Thus, the filter containing copper phthalocyanine retained a total amount of tobacco residue of 1.8 times that of the conventional cellulose acetate filter. More significantly, in the chromatogram area expected to represent various polycyclic aromatic hydrocarbons (retention time of 9-10 minutes), the filter containing copper phthalocyanine retained 15.6 times (ratio of 1.22X 107. mu.V-sec to 0.0793X 107. mu.V-sec) as much material as the conventional cellulose acetate filter. This experiment shows that the overall efficiency of the filter containing copper phthalocyanine according to one embodiment of the invention in retaining tobacco residue is improved and the selective trapping amount of mixed polycyclic aromatic hydrocarbons is increased compared to conventional cigarette filters.

Filter tip with microcapsule

According to another embodiment of the present invention, there is provided a tobacco smoke filter comprising a porous matrix having microcapsules dispersed therein, with or without other materials disclosed herein. The microcapsules preferably comprise an inner core with an outer shell.

The core of the microcapsule comprises at least one vegetable oil. Suitable vegetable oils include at least one oil selected from the group consisting of: castor oil, cottonseed oil, corn oil, sunflower oil, sesame oil, soybean oil, and rape oil. In a preferred embodiment, the vegetable oil is sunflower oil, as will be readily understood by those skilled in the art: other oils are also suitable. In a preferred embodiment, the vegetable oil is used in an amount of 20% to 80% by dry weight of the microcapsules, more preferably 30% to 70% by dry weight of the microcapsules.

In a preferred embodiment, the microcapsule core further comprises a porphyrin, such as: chlorophyllin, or another porphyrin, such as: copper phthalocyanine. The preferred amount of chlorophyllin is from 1% to 10% of the dry weight of the microcapsules, more preferably from 2% to 5% of the dry weight of the microcapsules.

The microcapsule shell includes a wetting agent. In a preferred embodiment, the wetting agent is sodium pyroglutamate, although it will be appreciated by those skilled in the art that: other wetting agents may also be used. In a preferred embodiment, wetting agents, such as: the amount of sodium pyroglutamate is from 10% to 90% of the dry weight of the microcapsules, more preferably from 20% to 70% of the dry weight of the microcapsules.

In another preferred embodiment, the microcapsule shell further comprises methylcellulose. In a preferred embodiment, the amount of methylcellulose is from 5% to 30% by dry weight of the microcapsules, more preferably from 10% to 25% by dry weight of the microcapsules.

In another preferred embodiment, the microcapsule shell comprises, in addition to or instead of methylcellulose, a polymeric agent, such as: polyvinyl alcohol or polyvinylpyrrolidone, or both polyvinyl alcohol and polyvinylpyrrolidone. In a preferred embodiment, the polymeric agent is used in an amount of from 2% to 30% by dry weight of the microcapsules, more preferably from 5% to 20% by dry weight of the microcapsules.

The compounds used to make the microcapsules of the present invention are commercially available from sources known to those skilled in the art, such as: sigma chemical company, st.

Microcapsules for use in the present invention may be prepared by various methods known to those skilled in the art, for example: the microcapsules according to the invention can be prepared by the following process, namely: 200g of vegetable oil were mixed with 500g of an aqueous suspension comprising 25 g of low-viscosity methyl cellulose, 5g of chlorophyllin, 50g of sodium pyroglutamate, 150g of corn starch, and the mixture was emulsified and spray dried to form microcapsules.

The microcapsules of the present invention may be formed by a spray drying process, namely: at the cigarette manufacturing plant, cellulose acetate tow is sprayed onto a cylindrical filter rod before it enters the filter. Alternatively, suitable microcapsules may be manufactured and applied to the cellulose acetate tow by dropping the microcapsules onto the tow by a vibrating disk, or by other techniques as will be appreciated by those skilled in the art. Further, the microcapsules are incorporated into the pre-formed filter by spraying the microcapsules onto the filter tow before the tow is wound and formed into a rod of filter material.

Those skilled in the art will appreciate that: the manufacture of filters containing microcapsules according to the invention requires only minor modifications to conventional filter cigarette manufacturing equipment. Moreover, filters containing microcapsules according to the invention are only a little more expensive to manufacture than conventional filters.

In use, the humectant portion of the microcapsules adsorbs the moisture of the tobacco smoke passing through the filter, sodium pyroglutamate being particularly preferred because it can enter the filter in dry form.

The oil portion of the microcapsules adsorbs a certain amount of harmful volatiles such as: pyridine, and does not prevent the passage of fragrance. Chlorophyllin is a strong inactivator of carcinogens in tobacco.

The methylcellulose fraction of the microcapsules imparts structural stability to the microcapsules, but disperses upon heating and is exposed to moisture. Unlike most conventionally used viscosity increasing substances, methylcellulose precipitates in hot solutions and, moreover, methylcellulose dissolves more readily at low temperatures than most conventionally used viscosity increasing substances.

The filter tip containing the microcapsules comprises sodium pyroglutamate, a methyl cellulose shell, vegetable oil and a chlorophyllin core, when the tobacco smoke is filtered, the microcapsules capture heat and moisture in the tobacco smoke, and the methyl cellulose is precipitated into a fiber material, so that the effective surface area for wet filtration of the tobacco smoke is increased. This allows moisture retained in the sodium pyroglutamate to be rapidly dispersed into the filter material with the chlorophyllin fraction being approximately uniformly located between the liquid and oil environments, which increases the ability to inactivate particles, gas phase poisons and carcinogens in the tobacco smoke more than if the chlorophyllin were in only one phase.

Filter tip containing surfactant

In another embodiment, the filter of the present invention further comprises at least one surfactant, with or without other substances disclosed herein, in order to improve the effectiveness of the tobacco smoke filter. In a particularly preferred embodiment, the surfactant is present in an amount of from about 0.1 to 10%, more preferably from 0.1 to 2% by weight of the filter.

The surfactant is preferably non-toxic and includes one or more of the following components: (1) a polyoxyalkylene derivative of a tartaric fatty acid ester (i.e., a polyoxyalkylene tartrate ester), (2) a fatty acid monoester of a polyhydric alcohol, or (3) a fatty acid diester of a polyhydric alcohol, although the use of other suitable surfactants will also be understood by those skilled in the art. Examples of suitable surfactants include ethoxylates, carboxylic acid esters, glycerol esters, polyoxyethylene esters, sorbitan esters, ethoxylated natural fats, oils and waxes, ethylene glycol esters of fatty acids, polyoxyethylene ester fatty acid amides, polyalkylene oxide block copolymers, and poly (oxyethylene) -including oxypropylene. Other suitable surfactants as understood by those skilled in the art may also be used.

Filter containing additive

The filter may additionally include one or more other substances which filter or inactivate tobacco poisons or carcinogens. Examples of such materials include antioxidants and radical scavengers such as: glutathione, cysteine, N-acetylcysteine, sodium mercaptoethanesulfonate, vitamin C, and N, N-diphenyl-p-phenylenediamine; acetaldehyde inactivators, such as: alkylene glycol compounds, amines, and amine thiols; nitrosamine traps and carcinogen inactivators, such as: ion exchange resin, chlorophyll; and nicotine traps, such as: tannic acid and other organic acids. In one embodiment, the filter comprises colloidal silica gel, a compound capable of scavenging secondary amines from the tobacco, thereby preventing conversion of the secondary amines to nitrosamines in the body. Other suitable materials as understood by those skilled in the art may also be used. In a preferred embodiment, the other materials are present in an amount of about 0.1% to 10%, more preferably 0.1% to 2% by weight of the filter.

Filters containing certain mixtures disclosed herein

According to another embodiment of the present invention, there is provided a tobacco smoke filter comprising a combination of compounds disclosed herein. In a preferred embodiment, the filter comprises a humectant, such as: sodium pyroglutamate is mixed with non-liquid water. This mixing function synergistically improves the wet filtration performance of tobacco smoke. In one embodiment, the filter includes sodium pyroglutamate in an amount of about 1% to 20% by weight of the liquid portion in the non-liquid water. In a preferred embodiment, the filter comprises sodium pyroglutamate in an amount of about 5% to 10% by weight of the liquid portion in the non-liquid water.

In another preferred embodiment, the filter comprises a copper-containing porphyrin, such as copper phthalocyanine, in combination with a humectant, such as: sodium pyroglutamate, non-liquid water, or both are wetting agents. These combinations are particularly preferred because copper-containing porphyrins are more effective at scavenging carcinogens in a liquid environment. In one embodiment, the copper-containing porphyrin is present in an amount of about 0.5% to about 5% by weight of the non-liquid water.

In another embodiment, the filter comprises chlorophyllin in combination with a humectant, non-liquid water, or both. In one embodiment, the chlorophyllin is present in an amount from about 0.5% to 5% by weight of the non-liquid water, and the wetting agent is present in an amount from about 1% to 20% by weight of the non-liquid water.

A particular example of such a mixture is blue viscose (copper phthalocyanine impregnated viscose) in combination with non-liquid water. This combination did not compromise stretch when the 0.3cm tobacco end in a standard cellulose acetate tobacco smoke filter was used in an amount of about 10 to 100mg, but the Ames test showed a reduction in tobacco smoke mutagenicity of 75% to 80%.

According to the method disclosed herein, a mixture of non-liquid water and porphyrin can be prepared by adding an equal amount of porphyrin to non-liquid water as methylated silica gel. The porphyrin must be added after the non-liquid water is completely stably emulsified. Separation of the porphyrin in water prior to emulsification on methylated silica gel can result in the production of unstable porphyrin/non-liquid water mixtures. In a preferred embodiment, the amount of porphyrin added per gram of methylated silica gel is from 0.1 to 0.5 g. A similar method is used to prepare a mixture of non-liquid water and porphyrin-derivatized fiber, such as blue cotton or blue viscose. After the two substances are mixed, the mixture is shaken or stirred to achieve homogeneity.

Filter tip comprising a circumferential partition

Filters according to the invention are preferably provided with an outer circumferential, moisture-impermeable barrier or cap to prevent the smoker's hand from becoming wet. Those skilled in the art will appreciate that such a cover is made of a polymeric material, such as ethyl vinyl acetate copolymer, polypropylene, or nylon.

Position of substance in filter

In accordance with the present invention, the substances disclosed herein may be incorporated into filters in various configurations, such as: the substance or substances may be dispersed in the filter in a substantially uniform manner, and in addition, the substance or substances may be dispersed only in a section of the filter, for example, in the proximal third (closest to the smoker end), the middle third, or the distal third (closest to the tobacco end).

In another embodiment, at least two substances are dispersed to different segments of the filter. The two segments may have an overlap region. For example, a filter according to the invention has non-liquid water dispersed in the distal third of the filter and a copper-containing porphyrin dispersed in the proximal third of the filter. Also for example: a filter according to the invention has microcapsules dispersed in the distal third of the filter and sodium pyroglutamate dispersed in the proximal third of the filter, so that the two substances are dispersed in an overlapping and non-overlapping region of the filter.

In another embodiment, the substance may be incorporated into a filter and then added to a standard tobacco smoke filter. In a preferred embodiment, the substance may be incorporated into a shortened form of tobacco smoke filter similar to a standard tobacco smoke filter and then added to a standard tobacco smoke filter. In this embodiment, the user will not perceive the additional shortened filter as being significantly shorter because it is similar in construction to a standard filter, unlike commercially available filters that are added to the proximal end of a tobacco product.

Further, the substance according to the invention may be incorporated into a lamina of the filter between the fibrous material filling the remainder of the filter and the tobacco body.

Filter-tipped tobacco articles incorporating the invention

According to another embodiment of the invention, there is provided a tobacco product comprising a tobacco smoke filter affixed to a body of tobacco, for example: the tobacco product may be a combination of a cigarette and a filter with microcapsules of sodium pyroglutamate dispersed therein.

Method for filtering tobacco

According to another embodiment of the present invention, a method of filtering tobacco in a smoking article is provided. The method comprises the following steps: firstly, a tobacco product is provided with a tobacco smoke filter according to the invention, and secondly, the filter is affixed to the tobacco body. The tobacco body is then ignited, causing smoke to pass through the tobacco body and into the filter. Finally, the smoke is allowed to pass through a filter capable of filtering the smoke.

Method for manufacturing tobacco products

According to another embodiment of the invention, there is provided a method of manufacturing a smoking article comprising the steps of first providing a tobacco smoke filter according to the invention and then affixing the filter to a body of tobacco.

Although the invention has been discussed in detail with reference to certain preferred embodiments, other embodiments are possible, and the spirit and scope of the appended claims should not be limited to those included herein

In a preferred embodiment.

Claims (44)

1. A tobacco smoke filter comprising a porous matrix having copper phthalocyanine dispersed therein.

2. A filter according to claim 1, wherein the porous matrix further has microcapsules dispersed therein, the microcapsules comprising an inner core and an outer shell.

3. A filter according to claim 2, wherein the microcapsules comprise sodium pyroglutamate.

4. A filter according to claim 2, wherein the microcapsules comprise methylcellulose.

5. A filter according to claim 1, wherein the porous matrix further has dispersed therein non-liquid water, said non-liquid water being a mixture of methylated silica gel and water.

6. A filter according to claim 1, wherein the porous matrix further has dispersed therein non-liquid water and microcapsules, said microcapsules comprising an inner core and an outer shell, said non-liquid water being a mixture of methylated silica gel and water.

7. A filter according to claim 1, wherein the porous substrate further has dispersed therein non-liquid water which is a mixture of methylated silica gel and water and sodium pyroglutamate.

8. A filter according to claim 1, wherein the porous substrate further has sodium pyroglutamate dispersed therein.

9. A smoking article comprising a tobacco smoke filter according to claim 1, wherein the filter is affixed to a body of tobacco.

10. A method of filtering tobacco in a smoking article comprising the steps of:

(a) providing a smoking article comprising a tobacco smoke filter according to claim 1, wherein the filter is affixed to a body of tobacco;

(b) igniting the body of tobacco so that the smoke flows through the body and into the filter;

(c) the smoke is passed through the filter to filter the smoke.

11. A method of making a smoking article comprising

(a) Providing a tobacco smoke filter according to claim 1; and

(b) the filter is attached to a tobacco body.

12. A tobacco smoke filter consisting essentially of a porous matrix having copper phthalocyanine dispersed therein.

13. A smoking article comprising a tobacco smoke filter according to claim 12, wherein the filter is affixed to the body of tobacco.

14. A method of filtering tobacco in a smoking article comprising the steps of:

(a) providing a smoking article comprising a tobacco smoke filter according to claim 12, wherein the filter is affixed to a body of tobacco;

(b) igniting the body of tobacco so that the smoke flows through the body and into the filter;

(c) the smoke is passed through the filter to filter the smoke.

15. A method of making a smoking article comprising

(a) Providing a tobacco smoke filter according to claim 12; and

(b) the filter is attached to a tobacco body.

16. A tobacco smoke filter consisting essentially of a copper-containing porphyrin and a porous matrix having microcapsules dispersed therein, said microcapsules comprising a core and an outer shell.

17. A filter according to claim 16, wherein the microcapsules comprise sodium pyroglutamate.

18. A filter according to claim 16, wherein the microcapsules comprise methylcellulose.

19. A smoking article comprising a tobacco smoke filter according to claim 16, wherein the filter is attached to the body of tobacco.

20. A method of making a smoking article comprising

(a) Providing a tobacco smoke filter according to claim 16; and

(b) the filter is attached to a tobacco body.

21. A tobacco smoke filter consisting essentially of copper phthalocyanine and a porous matrix in which a non-liquid water is dispersed, said non-liquid water being a mixture of methylated silica gel and water.

22. A smoking article comprising a tobacco smoke filter according to claim 21, wherein the filter is attached to the body of tobacco.

23. A method of filtering tobacco in a smoking article comprising the steps of:

(a) providing a smoking article comprising a tobacco smoke filter according to claim 21, wherein the filter is attached to a body of tobacco;

(b) igniting the body of tobacco so that the smoke flows through the body and into the filter;

(c) the smoke is passed through the filter to filter the smoke.

24. A method of making a smoking article comprising

(a) Providing a tobacco smoke filter according to claim 21; and

(b) the filter is attached to a tobacco body.

25. A tobacco smoke filter consisting essentially of copper phthalocyanine, non-liquid water and a porous matrix having microcapsules dispersed therein, said microcapsules comprising an inner core and an outer shell, said non-liquid water being a mixture of methylated silica gel and water.

26. A smoking article comprising a tobacco smoke filter according to claim 25, wherein the filter is attached to the body of tobacco.

27. A method of filtering tobacco in a smoking article comprising the steps of:

(a) providing a smoking article comprising a tobacco smoke filter according to claim 25, wherein the filter is attached to a body of tobacco;

(b) igniting the body of tobacco so that the smoke flows through the body and into the filter;

(c) the smoke is passed through the filter to filter the smoke.

28. A method of making a smoking article comprising

(a) Providing a tobacco smoke filter according to claim 25; and

(b) the filter is attached to a tobacco body.

29. A tobacco smoke filter consisting essentially of a porous matrix having dispersed therein copper phthalocyanine and sodium pyroglutamate.

30. A smoking article comprising a tobacco smoke filter according to claim 29, wherein the filter is attached to the body of tobacco.

31. A method of filtering tobacco in a smoking article comprising the steps of:

(a) providing a smoking article comprising a tobacco smoke filter according to claim 29, wherein the filter is attached to the body of tobacco;

(b) igniting the body of tobacco so that the smoke flows through the body and into the filter;

(c) the smoke is passed through the filter to filter the smoke.

32. A method of making a smoking article comprising

(a) Providing a tobacco smoke filter according to claim 29; and

(b) the filter is attached to a tobacco body.

33. A tobacco smoke filter consisting essentially of a porous matrix having dispersed therein copper phthalocyanine, non-liquid water which is a mixture of methylated silica gel and water, and sodium pyroglutamate.

34. A smoking article comprising a tobacco smoke filter according to claim 33, wherein the filter is attached to the body of tobacco.

35. A method of filtering tobacco in a smoking article comprising the steps of:

(a) providing a smoking article comprising a tobacco smoke filter according to claim 33, wherein the filter is attached to a body of tobacco;

(b) igniting the body of tobacco so that the smoke flows through the body and into the filter;

(c) the smoke is passed through the filter to filter the smoke.

36. A method of making a smoking article comprising

(a) Providing a tobacco smoke filter according to claim 33; and

(b) the filter is attached to a tobacco body.

37. A tobacco smoke filter comprising a porous substrate having copper-containing porphyrin dispersed therein.

38. A tobacco smoke filter comprises a porous matrix with non-liquid water and porphyrin dispersed therein, wherein the non-liquid water is a mixture of methylated silica gel and water.

39. A tobacco smoke filter consisting essentially of a porous substrate having copper-containing porphyrin dispersed therein.

40. A tobacco smoke filter consisting essentially of a porous matrix having dispersed therein non-liquid water which is a mixture of methylated silica gel and water and a porphyrin.

41. A tobacco smoke filter consisting essentially of a porous substrate having sodium pyroglutamate and a copper-containing porphyrin dispersed therein.

42. A smoking article comprising a tobacco smoke filter according to any one of claims 37 to 41, wherein the filter is attached to a body of tobacco.

43. A method of filtering tobacco in a smoking article comprising the steps of:

(a) providing a smoking article comprising a tobacco smoke filter according to any one of claims 37 to 41, wherein the filter is attached to a body of tobacco;

(b) igniting the body of tobacco so that the smoke flows through the body and into the filter;

(c) the smoke is passed through the filter to filter the smoke.

44. A method of making a smoking article comprising

(a) Providing a tobacco smoke filter according to any one of claims 37 to 41; and

(b) the filter is attached to a tobacco body.