Patent Application
20180360106
The present disclosure relates to the field of smoking product filtration, including cigar and cigarette filtration. In particular, it relates to the addition of one or more layers of nano filters and/or micro filters to the filter and the body of tobacco products, including but not limited to cigarettes and cigars, in the aim of effectively reducing the inhalation of toxic and hazardous substances and tar by the human body. Nano filters are composed of nanomaterials of which a single unit is sized (in at least one dimension) between 1 and 1000 nanometers, including but not limited to nanofibrous materials, carbon nanotubes, carbon nanotube membranes, and graphene oxide. Micro filters are composed of micromaterials of which a single unit is sized (in at least one dimension) between 1 and 1000 micrometers, including but not limited to meltblown nonwoven fabrics, carbon fibers, carbon fiber cloths, carbon membranes, and carbon fiber membranes. Nanomaterials and micromaterials can be interwoven or synthesized together to form a filter with mixed sizes of constituent elements. The present disclosure also relates to a method for preparing nanofibrous layers using electrospinning.
In order to minimize the impacts of smoking on human health, to protect the health of people living around the smokers and in the environment affected by smoking, and to prevent the intake of respirable particulate matters and other harmful and unhealthy substances from smoking into human body, there is increasing attention on adding filter layers to cigarettes. A variety of filtering methods and filter materials have been studied for cigarette filtration. However, conventional research and the application of filter materials to reduce the inhalation of particulate matter have not fully met the filtration requirements on the particles and harmful substances generated during cigarette smoking.
In the last century, cigarette filters have widely been used to reduce the harmfulness of smoking on human health. In the 1930s, doctors and researchers published a series of studies on the relation between smoking and lung diseases. At that time, cigarette filters began to receive attention. The purpose of a filter in a cigarette is to reduce the amount of tar and suspended particles in smoke inhaled by a smoker from burning tobacco. There is a dilemma: in order to block tar and small-sized particles, the filter has to be less porous, with high filtration efficiency, but unfortunately as a result, the filter easily becomes clogged by tar and toxic articles. If a filter is clogged, it is impossible for smokers to smoke after only a few puffs. There is an urgent need to find a solution such that fine particles can be blocked while smokers do not suffer from clogged filters.
Electrospinning is a technique that uses a polymer solution or a melt to form a jet stream under a strong electric field for spinning. In recent years, due to its ultra-fine fiber processing technology, electrospinning has received more and more attention. There are currently at least 30 kinds of polymers that can be electrospun, including natural polymers such as DNA, collagen, and silk protein, and synthetic polymers including polyoxyethylene, polyacrylonitrile, nylon, polyvinyl alcohol, polyurethane, and polyester. Compared to other methods that are expensive, time-consuming, and easy to cause pollution, electrospinning can save a lot of cost and energy.
In order to enhance the filtration of tar, nicotine, and suspended particles, various materials and structures for a cigarette filter have been proposed. PCT application WO 2004/080217 A1 discloses a method of electrically processed phenolic materials and the application of such materials to cigarettes. The method of electrical processing in WO 2004/080217 A1 is essentially the same as the electrospinning method, but the method also includes steps of drying and high-temperature carbonization after electrical processing. The method can be used for to produce nano/micro fibers and particles. Such anodized phenolic materials used in cigarettes are not safe. Also, carbonated phenolic materials are brittle and easy to be inhaled. When fine micro/nano fibers or particles are used as filler materials in the filter and placed in the filter with a small pore size, the filter layer is easily clogged with tar or particles of harmful substances.
PCT application WO 2007/048359 A1 discloses the design of mixing 5 to 10 percent nanofibers into a micron fiber filter. With the introduction of nanofibers, it increases the surface area of the material and hence its filtration capacity. The disclosure in WO 2007/048359 A1 still uses conventional acetate fibers as filter materials. This disclosure provides a small improvement on filtration effects because the amount of nanofibers is low. At the same time, due to the mixed design of using nano and micron fibers, the tar, nicotine, suspended particles are more likely to pass through the micron fibers. The nanofibers do not function well, as when fine micro/nano fibers or particles with small pore sizes are placed in the filter as filter materials, the filter layer is easily clogged with tar or particles of harmful substances.
PCT application WO 2013/164623 A1 discloses the addition of short fibers with adsorbents or adsorbed particles on the surface of the cigarette filters. The diameter and length of the short fibers are approximately 5-9 millimeters and 5-20 millimeters, respectively. Short fibers are a mixture of acetate fibers and other common polymer fibers. The size of the adsorbents or adsorbed particles, including activated carbon, on the fibers is between 0.1 and 1 millimeters. The materials used in the invention do not reach the nanoscale either in the diameter of the fiber or in the particle size. The materials are not safe.
Chinese patent CN 102423141 A discloses a method for using an electrospun acetate fiber membrane in the cigarette filter to improve the efficiency of harmful substances filtration. The solvents used are acetone and dimethyl acetamide. Solvent residues are likely contained in the electrospun membrane if the solvent evaporation is not well completed during the production process, leading to potential health risks to smokers. The patent puts the fiber membrane inside the cigarette filter tip portion. Filtration effects and respiratory resistances cannot be well controlled.
Chinese Patent CN 103625090 A discloses a method to prepare a nanofiber membrane modified paper substrate by electrospinning and its application. The nano-spun yarns are between 500 nm and 1 μm in diameter, with a narrow spinning range and larger diameter than the effective nanomaterial filtration.
Because of their excellent filtration effects, electrospinning materials have been developed as filter materials, such as masks, to improve human respiratory health. Chinese Patent CN 104740934 A discloses a stereoscopic electrospinning filter material for a mask and a preparation method thereof. The invention uses polyvinyl butyral as a substrate, and a micro/nanofiber film of 0.2 microns to 1.5 microns in size is prepared on a stereoscopic model using an electrospinning technique. The solvent used in CN 104740934 A is ethanol, which is not as safe and reliable as using a water solvent to produce nano fibers for large-scale production. The diameters of micro/nano fibers prepared in the disclosure in CN 104740934 A are in the range of 0.2 to 1.5 microns, a range that is too small, and the control of the product is not as good. The spinning solution concentration of the polymer polyvinyl butyral is 0.06 g/ml, which is too low.
Chinese Patent CN 102872654 A and CN 102920067 A disclose the use of electrospinning to produce a mask capable of filtering pollutants of 2.5 microns in size or larger. However, the polymer used and the solvents used for preparing the electrospinning solution are toxic, posing serious health risks if a complete evaporation of solvent cannot be achieved. At the same time, the filter materials prepared by these patents are not as effective for filtration of pollutants of 2.5 microns in size or larger.
A first advantage of the present disclosure relates to the placement of one or more filters in a body of a tobacco product or other body for smoking to filter harmful substances caused by smoking thereby protecting human health. The advantage of adding filters to the cigarette body is that the filters can be burnt up, before they are clogged by the accumulation of tar and particles, along with the tobacco in the cigarette body.
A second advantage of the present disclosure is that the surface area of the filter(s) can be increased when specific shapes of the filters are adopted, thereby allowing the same sized filter to tolerate a higher amount of tar without clogging.
A third advantage of the present disclosure is that when multiple filter layers are deployed within one filter, their porosities and thicknesses can vary and they can be placed in either the cigarette filter and/or body section, e.g., filter layers with larger porosities can be closer to the lit end of the cigarette to capture larger contaminants and filter layers with smaller porosity can be closer to the mouth of the smoker to capture smaller contaminants. The porosity determines the sizes of the contaminants that a filter layer can capture, with less porous filters being able to block smaller particles. As a result, finer filter layers, or filter layers that are less porous will unlikely be clogged by larger contaminants, hence enhancing their capability to block more finer contaminants. Similar results can be achieved when multiple filters—but with different porosities—are placed in either the cigarette filter and/or body section.
These and other features, aspects, and advantages of the present disclosure will become better understood with regard to the following description, appended claims, and accompanying drawings where:
The present disclosure can be better understood by the following discussion of the manufacture and use of certain preferred embodiments. Like reference numerals are used to describe like parts in all figures of the drawings.
This present disclosure applies one or more filters in tobacco products including but not limited to cigarettes and cigars, especially for the filtration of toxic suspended particles, with each filter capable of containing one of more layers. Both the layers and filters can display different porosities. Preferably, the filters have a large surface area. Using nano-sized and/or micro-sized particle filtration, the filters can effectively reduce tar and other harmful impurities in smoke, or aerosol, and reduce irritation to the respiratory tracts to protect human health. Filters in the present disclosure can be made of biodegradable materials. Preferably, the selected materials are not toxic and have no side effects. Nanofibers produced by electrospinning can be used in the filters due to their cost effectiveness.
In the present disclosure, the concept of filtration includes any or a combination of various mechanical, physical, chemical, or biological operations or materials that blocks, restricts, adsorbs, traps, disintegrates, destroys, damages, or has any means of restricting certain substances from passing from one point to another, or filter. The substances filtered can be in solid, liquid or gas format.
During the combustion of tobacco leaves, a plurality of harmful gaseous components may be generated, including but not limited to at least one of carbon monoxide, ammonia, 1,3-butadiene, isoprene, acraldehyde, acrylonitrile, hydrogen cyanide, 0-toluidine, 2-naphthylamine, nitrosamine, nitrogen oxide, benzene, n-nitrosonornicotine (NNN), phenol, catechol, benzoanthracene, and benzopyrene. A large number of studies have been carried out on reducing harmful gaseous components from burning tobacco, such as applying filter tips. Such filter tips are often clogged or filled with tar after only a few puffs. According to the present disclosure, the filter(s) is directly placed in the cigarette body, and the filter(s) has a specific adsorption effect and/or is mixed with a specific catalyst, so that more harmful materials can be removed when the filter(s) is designed to possess a large surface area. Particularly, the filter(s) can be burnt out along with the combustion of the tobacco in the cigarette body. Harmful chemicals can be subject to thermal decomposition and/or catalytic decomposition under the high temperature of combustion, and thus reducing inhalation of harmful gas by human body.
When cigarettes are burned, aerosol and tar are produced. After cooling down, tar is in oily liquid form, containing a large number of harmful substances. It's important to filter and remove selectively the harmful substances, and reduce tar. As nicotine and flavor chemicals are also in the aerosol and tar, care needs to be taken to preserve flavors. General tar filtration methods using acetate fibers only are problematic because the filters quickly become clogged. In cases when fine or ultrafine fibers are employed to remove small aerosol particles, smokers often cannot even smoke after a few puffs.
The present disclosure employs two approaches to avoid the clogging problem.
First, one or more filters can be placed in a body of a tobacco product. In case there is more than one filter, the number of filters per unit distance can be set to increase gradually towards the filter tip portion (non-lit end) of the cigarette. Tar clogging can be avoided as the filter or filters close to the lit end are burned subsequently during smoking. That is, as more and more tar accumulates on the filter closer to the lit end, that filter is to be burned when smoking continues, thereby destroying the clogged filter. In another variation of the current design where multiple filters are employed, the number of filters per unit distance remains the same, but the thickness of each layer is gradually increased toward the end of the cigarette, which can also prevent the clogging of the tar while maintaining a high filtration efficiency.
Secondly, multiple layers with different porosities can be bound together to form a filter, called a multi-layer filter, to alleviate the clogging problem. A multi-layer filter effectively enlarges the surface area for filtration. In the present disclosure, one or more multi-layer filters are placed in either the cigarette body, or the tobacco section, or both. The layer(s) that is more porous or that can block only coarse or large particles can be located closer to the lit end of the cigarette, while the layer(s) that is less porous or that can block finer particles can be located closer to filter tip portion of the cigarette. With such an arrangement, larger particles will be blocked or absorbed by the layer(s) closer to the lit end. They will not clog the layer that is designed to block finer particles.
Referring now to
Referring now to
Referring now to
The filter 160 can comprise of one or a combination of a nanofiber layer or a micro meltblown nonwoven layer, and/or other layers with different porosities. In the exemplary embodiment of
Although the filters in
In the present disclosure, the micro or nanofiber filter layers can be manufactured by electrospinning and/or meltblowing techniques. These techniques can be applied to the nanotube membrane and micro membrane filters, which use synthetic and natural polymers as their raw materials. Based on modern micro/nano technologies, the aforementioned filters can significantly reduce the amount of particulate matters and toxic substances inhaled.
In the embodiment shown in
Preferably, a material for preparing the filters or filter layers is filled with a catalyst for decomposing, selectively, toxic matters. For example, CO generated by incomplete combustion of tobacco can be converted into CO2 by using a transition metal-manganese composite oxide catalyst or a catalyst containing CuO, MgO. For another example, hydrogen cyanide can be catalytically decomposed into non-toxic substances by using silver nitrate and nickel nitrate nanoparticles or using cobalt oxide or nickel oxide. Similarly, the level of phenol in smoke or aerosol can be reduced by using copper nitrate and cobalt nitrate. Nitrosamine can be catalytically decomposed by using one or more rare earth oxides such as lanthanum oxide, cerium oxide and praseodymium oxide.
More preferably, the catalysts included within one or more filters can be activated or remain active under high-temperatures. Catalysts can be selected from a relatively wide range, for example, having an activation temperature of between 600˜1000° C. Tobacco combustion can provide the desired high temperature for catalyst activation.
Preferably, the materials used to make the filters and filter layers can selectively adsorb certain toxic gaseous components. When such filters are placed in cigarette body and subsequently burned during smoking, some or most of the toxic matters adsorbed by the filters are subject to thermal decomposition. Selective adsorption can be combined with the catalysts mentioned earlier to better facilitate the elimination of harmful chemicals resulting from burning tobacco.
The present disclosure discloses a group of high efficiency filter materials which can be used for filtering for tobacco products, including electrospinning nanofibers, nanotubes, meltblown micrometer nonwoven fabrics, spunlace nonwoven fabrics, cellulose acetate filter layer, phenolic filter layer, synthetic polymer filter layer, activated carbon particles and the like, or combinations thereof. Electrospun nanofibers can be prepared using one or a mixture of synthetic polymers and natural polymers under normal temperature and pressure. The electrospun nanofibers can be sprayed directly onto the surface of the meltblown or spunlace nonwoven fabrics to form a composite adsorbent filter, or they can be sprayed directly to tobacco or matters in the cigarette body portion, or sprayed directly onto or mixed with acetate fibers or other materials in the cigarette filter tip portion. The materials include synthetic polylactic acid, polyvinylpyrrolidone, nylon, poly Diols, polyvinyl alcohol, chlorinated polyvinyl chloride, diacetate, polyether sulfone, and natural polymers such as chitosan, silk protein, corn gluten, and combinations thereof. They can be dissolved in water, formic acid, glacial acetic acid, ethanol, isopropyl alcohol in the concentration range of 10˜500 mg/ml,
For electrospinning, the concentration of the polymer solution can be 10 to 500 mg/ml, and the solvent can be one or a mixture of the volatile solvents. The number of syringes can be set to 1-2000 as needed, the number of electrospinning needles can be set to 1-2000 as needed. The voltage of electrospinning is the combination of positive voltage, which is in the range of 0˜200 kV, and negative voltage, which is in the range of −0˜−200 kV. The total voltage difference is 10˜400 kV, the solution moving speed of each needle is 0.1-50 ml/hr, and the distance from the spinning needle to the receiving plate is 5-200 cm. The electrospinning process can also be carried out using a wire instead of the needles.
As described above, the filters described in the present disclosure may be made by the process of electrospinning. The material(s) and the electrospinning parameters used can be selected to provide filters like those described above with the desired sizes and desired filtering characteristics. One or more catalysts can be added to the filters if desired. The filters can be located within a body of a tobacco product in the desired location during manufacturing of the tobacco product. For example, the body of the tobacco product may be considered as comprising a plurality of segments, and the body can be filled with alternating portions comprising primarily or consisting essentially of filter or tobacco. Alternatively, the body portion of a tobacco product may be filled with tobacco or one or more filters, then with one or more filters or tobacco, respectively, and so on, such that the body portion of the tobacco product comprises alternating one or more tobacco portions and one or more filter portions. In one embodiment, a filter material can be electrospun onto a tobacco product to create a mixed composition of tobacco and filter materials, with the resulting mixed composition then placed into a body portion of a tobacco product, with that body portion able to include one or more additional filters like those shown and described herein if desired.
It should be noted that a tobacco product may include a plurality of filters, each adapted to provide certain desired filtering characteristics. As noted, two or more filters having different porosities from one another can be placed in the body of the tobacco product, thereby providing a size gradient for filtering particulates. In addition, two or more filters, each having one or more catalysts thereto, wherein the catalysts may differ from filter to filter, can be located in the body of the tobacco product to thereby provide a variety of filtering or adsorption characteristics as may be desired. Moreover, two or more filters, having the same or different shapes, the same or different sizes, and/or comprising the same or different materials, may be located within the body of the tobacco product to provide the desired filtering characteristics.
Although the present disclosure has been described with reference to specific exemplary embodiments, it will be recognized that the disclosure is not limited to the embodiments described, but can be practiced with modification and alteration within the spirit and scope of the appended claims. For example, although most of the foregoing discussion refers to cigarettes and to tobacco products, it should be noted, however, that the systems and methods of the present disclosure can be used in a wider variety of products. For example, filters like those described above may be included in cigars as well as cigarettes. Similarly, filters like those described above may be included in and part of other smoking implements, such as pipes, hookahs, bongs, and the like. Moreover, it should be noted that, although the foregoing discussion has focused on tobacco products and the smoking thereof, the filters and methods described above may be used in connection with other smoking products, such as pipe tobacco, marijuana, hashish, tobacco mixed with molasses or other sweeteners or flavors, other smoking materials for hookahs, and combinations thereof. Accordingly, the specification and drawings are to be regarded in an illustrative sense rather than a restrictive sense. Unless otherwise specifically stated, the terms and expressions have been used herein as terms of description and not terms of limitation. There is no intention to use the terms or expressions to exclude any equivalent of features shown and described or portions thereof and this disclosure should be defined in accordance with the claims that follow.
This application claims the benefit of priority of U.S. provisional patent application Ser. No. 62/521,048, which was filed on June 16, 2017, and which is hereby incorporated herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| 62521048 | Jun 2017 | US |
