FI81950C - TOBAKSPRODUKT MED FOERBAETTRADE MEDEL FOER AVGIVANDE AV AROMAEMNEN. - Google Patents

Description

A tobacco product with improved means for releasing flavorings. - Tobaksprodukt med förbättrade medel för avgivande av aromämnen.

, 81950

The present invention relates to tobacco products according to the preamble of claim 1, which generally have a fuel element, a physically separate aerosol generating means, and improved means for releasing one or more volatile flavorings to the user. As used herein, the term "tobacco product" includes cigarettes, cigars, pipes and other tobacco products that emit aerosols, such as smoke. More particularly, the present invention relates primarily to a carbon-filled sheet, preferably containing tobacco, wherein the sheet is used at least as part of the mouthpiece of such products for storing flavoring agents, especially highly volatile flavoring agents such as menthol.

Cigarettes, cigars and pipes are the most popular forms of smoking tobacco products. Over the years, several tobacco products and articles have been presented as an improvement or alternative to these popular tobacco products, especially cigarettes.

For example, many have suggested tobacco substitutes. See. for example, U.S. Patent 4,079,742. Two such substances, Cytrel and NSM, were introduced in Europe in the 1970s as a partial substitute for tobacco, but they did not achieve any long-term commercial success.

Many others have suggested tobacco products, especially smoke-fume products based on aerosol or vapor generation. See. for example, those disclosed in the prior art in U.S. Patent 4,714,082.

None of the aforementioned tobacco products, to the knowledge of the present inventors, have ever achieved any commercial success, nor have any of them been widely marketed. The absence of such tobacco products from the market is probably due to several reasons, incl. unsatisfactory development of aerosols, both initially and during the life of the product, poor taste, deterioration of taste due to heat of the smoke generator and / or flavor, presence of significant amounts of pyrolysis product and by-product smoke, and unpleasant appearance.

Thus, despite decades of interest and effort, there is still no tobacco product on the market that produces the benefits, advantages, and pleasures associated with smoking without producing significant quantities of incomplete combustion and pyrolysis products.

Recently, however, patent publications EP 0174645, EP 0212234 and US 4,714,082 and FI patent application no. 883873 describes tobacco products, particularly cigarette products, that can provide the benefits, advantages, and enjoyment associated with smoking without producing significant amounts of incomplete combustion or pyrolysis products. The improved flavor release means of the present invention are particularly suitable for use in such products.

Menthol-treated tobacco products represent a significant share of the total market. In fact, almost a third of all cigarettes manufactured are to some extent treated with menthol. However, one problem with menthol and other volatile and semi-volatile flavorings used in tobacco products is that flavorings usually migrate to other parts of the product. Such migration is well documented in the literature. See. for example, M.Brozinski et al., Beitrage zur Tabaksforschung International 6, ss. 124-130 (1972); J.G.Curran, Tobacco Science 17, p. 10-11 (1973). In cigarettes, migration occurs regardless of whether the flavors are contained in the tobacco, filter, coating material, or packaging material (e.g., menthol-treated film). The end result is similar for all such applications. During storage, an equilibrium level of flavorings is created, allowing the flavorant to pass through the entire tobacco product and associated packaging. The degree of migration depends on e.g. the vapor pressure of the flavoring agent, its solubility in the various components of the product and its relative humidity, as well as the resistance to migration of different substances (e.g. tobacco, coating, filter aid, adhesive, etc.).

Some attempts have been made to solve migration problems, but they have achieved only limited success. For example, various chemicals have been used, such as chemically bound non-volatiles to reduce migration (e.g., beta-cyclodextrin-menthol complexes, menthol glucosides, menthol amides, esters, etc.). See. e.g., U.S. Patents 3,426,011 and 3,344,796. In general, all of these substances have limited uses, due to the cost and poor taste of the smoke produced.

Others have studied the so-called the use of microencapsulated perfumes in different parts of the tobacco product. See. for example, U.S. Patents 3,550,598 and 3,540,456, and CH 475,418 and NL 8201585.

Others have encapsulated volatile flavors in polymer systems such as linear low density polyethylene and inorganic filters, e.g., CaCO 3, alumina, etc., and placed these substances in the form of pellets or fibers or particles in filter systems or packaging systems. The problem with this approach is the persistence of migrations (albeit in a controlled manner), the often large amounts of flavoring agents required in substances at a cost, and the low overall rates of flavoring release, usually at levels of 1 to 18% by weight.

4,81950

The use of carbon in different parts of cigarettes has also been suggested. In particular, carbon has been used in wrapping systems, as a filler, in filters to reduce gas phase smoke particles, and to introduce flavorants into a cigarette. See. e.g., U.S. Patents 2,063, 104; 3,744,496; 3,902,504; 4,505,202 and 4,225,636. However, carbon, and in particular activated carbon, has not achieved significant commercial use as a carrier for flavoring agents such as menthol, since activated carbon e.g. adsorbs most of the menthol before it can be released to the smoker. To compensate for this phenomenon, the carbonaceous substance is usually impregnated with a flavoring agent. However, as noted above, it results in undesired migration of the flavorant to other parts of the tobacco product. See. e.g., U.S. Patent 3,236,244, which describes the use of activated carbon and the removal of unwanted portions from smoke and the release of flavoring agents therein.

U.S. Pat. No. 3,972,335 recognizes this problem. It shows the closure of small pores of activated carbon with a pore-modifying agent such as sucrose. The pore modifier is explained to be used in such amounts that the less retaining portions of the activated carbon are not sealed but remain to be used to adsorb the flavoring agent. Thus, this increases the durability of storing the tobacco product by reducing the transport of the flavoring agent but allowing for the effective release of the flavoring agent during smoking. However, there appears to be significant migration of more than about 40%. See. example, I columns 5-6. As a result, carbon filters or carbon coatings are not generally recommended for menthol-treated tobacco products.

The present invention relates generally to a tobacco product according to the preamble of claim 1 having a fuel element, physically separate aerosol generating means, and improved means for releasing menthol and other volatile flavors with the aerosol without significant migration of flavor to the fuel element or other parts of the tobacco product. The improved flavorant release means of the invention includes that the release means comprises 5,81950 carbon-filled sheet material containing at least one flavorant.

This carbon-filled sheet material is located in a non-combustible portion of the tobacco product, e.g., any portion of the product that is longitudinally located behind the fuel element and at a distance from the fuel element. However, it is preferably in the form of a cylinder segment or plug located between the aerosol generating means and the mouthpiece of the tobacco product.

Preferably, tobacco products using improved flavor release means are cigarettes using a short, i.e. less than 30 mm long, preferably carbonaceous fuel element. Preferably, the aerosol generating means is located longitudinally behind the fuel element and in thermally conductive communication with the fuel element. The mouthpiece preferably comprises a filter segment, which preferably has a relatively low efficiency, in order to avoid its interaction with the aerosol produced by the aerosol generating means. The flavor release means of the present invention comprises a carbon-filled sheet material that can be used in any non-combustible portion of the tobacco product, i.e., any portion that is longitudinally located behind or otherwise spaced from the fuel element. Preferably, it is located between the filter segment and the aerosol generating means. In certain preferred embodiments, the flavor release means comprises a segment of wrapped, folded, or assembled sheet of carbon-filled tobacco paper having a length of about 5-15 mm.

It has been found that the improved flavoring release means of the present invention helps to reduce the migration of flavorings, especially menthol and other volatile flavorings, to other parts of a tobacco product or to equipment used in the manufacture of such products. The reduction of migration to the fuel source is particularly important due to the unfavorable taste nuisance that can result from the thermal decomposition or pyrolysis of aromatics in the combustible fuel element. The reduction in migration also contributes to prolonging the shelf life of volatile flavorings, such as 6 81,950 tobacco products containing menthol. It has also been found that flavoring agents are smoked evenly and easily from the carbon-filled sheet material when smoking as aerosols and hot gases from the aerosol generating means pass along or through the sheet material. It is believed that somewhat higher than normal temperatures immediately behind the aerosol generating means contribute to the uniform release of flavoring agents throughout the life of the tobacco product. In addition, tobacco products that use a carbon-filled sheet material as a component of the mouthpiece provide such less migration and uniform release of flavors without a substantial reduction in the release of other aerosol components, e.g., glycerin, water, and the like. In other words, the filtration efficiency of the carbon-filled sheet material is substantially lower than that of other cigarette filter materials, such as cellulose acetate tow. This is important in maintaining the desired release of the aerosol generated by the tobacco products of the present invention.

The preferred carbon-filled sheet material according to the invention also acts as a coolant, which helps to lower the temperature of the aerosol received by the smoker and also helps to prevent the filter material from melting or deteriorating.

Preferred tobacco products using the improved flavorant release device of the present invention are capable of releasing at least 0.6 mg of aerosol, measured as wet total particulate matter (WTPM), during the first three breaths when smoked under FTC smoking conditions comprising two 35-second breaths of two seconds separated by a 58-second glow time. Even more preferably, embodiments of the invention can release 1.5 mg or more of aerosol during the first three breaths. Most preferably, embodiments of the invention can release 3 mg or more of aerosol during the first three breaths under FTC smoking conditions. In addition, preferred embodiments of the invention release on average at least 0.8 mg of WTPM per breath during at least six breaths, preferably at least 10 breaths, under FTC smoking conditions.

7 81950

In addition to the above advantages, the preferred tobacco products of the present invention can provide an aerosol that is chemically simple, comprising substantially air, carbon oxides, water, an aerosol former, any desired flavors or other desired volatiles, and residues of other substances. Preferably, the aerosol also does not have any significant mutagenic effect as measured by the Ames Test. In addition, the inexpensive products can be made seemingly ashless so that the user does not have to remove the ash during use.

As used herein, and for the sole purpose of this specification, an "aerosol" is defined to include vapors, gases, particles, and the like, both visible and invisible, and in particular those ingredients which the user considers "smoke-like" and which are generated by the temperature of the combustible fuel element. substances in an aerosol generating device or elsewhere in the product.

As used herein, "conductive heat transfer" is defined as the physical arrangement of an aerosol generating means and a fuel element, wherein heat is transferred by conduction from the combustible fuel element to the aerosol generating means during substantially the entire fuel cell combustion cycle. Conductive heat transfer can be achieved by placing the aerosol generating means in contact with the fuel element and thus close to the combustible portion of the fuel element, and / or by using a conductive member to conduct heat from the combustible fuel to the aerosol generating means. Preferably, both methods of heat conduction are used.

As used herein, the term "carbon-filled" means primarily carbonaceous.

8 81950 As used herein, the term "insulating member" applies to all materials that primarily act as insulators, preferably do not burn during use, but may contain slow-burning carbon or similar substances, as well as substances that melt during use, such as low temperature Suitable insulators have a thermal conductivity [in g-cal (s) (cm2) (° C / cm)] of less than 0.05, preferably less than 0.02 and most preferably less than 0.005, see Hackh's Chemical Dictionary, s 672 (4th edition, 1969) and Lange: Handbook of Chemistry 10, pp. 272-274 (11th edition, 1973).

The improved tobacco products using the flavor release means of the present invention are described in more detail in the accompanying drawings and the following detailed description of the invention.

Figure 1 is a longitudinal section of a preferred cigarette using the improved flavor release means of the present invention.

Figure 1A illustrates, as seen from the ignitable end, the preferred channel structure of the fuel element.

Figure 2 illustrates the results of the migration study with preferred cigarettes, some of which are provided with a carbon-filled sheet material according to the present invention.

Figure 3 schematically illustrates a method of forming a carbon-filled sheet material into a filter plug-shaped cylinder segment.

Figure 3A illustrates a dual cone system used to collect or fold material into the shape of a filter plug.

9,81950

According to the present invention, there is provided an improved flavor release means for use in a tobacco product. The flavor release means is particularly well suited for tobacco products with a small combustible fuel element, a physically separate aerosol generating means and a separate mouthpiece, as in the products described in the above-mentioned EP 174,645 and 212,234.

In general, the improved flavor release means comprises a carbon-filled sheet material, typically formed by adding carbon (active, inactive, or a mixture thereof) to a regular paper pulp, such as pulpwood or flax fibers and / or pulp tobacco stems and stems. This material is then formed into a sheet material using conventional papermaking methods.

Although the porosity of the carbon-filled sheet material can vary over a wide range, it preferably has a characteristic porosity of between 100 and 250 CORESTA units, and a net porosity of more than 150 CORESTA, preferably between 300 and 30,000 CORESTA. Net porosity is obtained by making holes by mechanical, electrostatic or laser means, and / or by slitting the sheet material. Sheet materials in this region of porosity are particularly preferred because it allows a greater amount of flavor to be placed in the carbon-filled sheet material by adsorption and / or absorption mechanisms, and because the total surface area of the flavor release means can be increased very much without increasing the carbon-filled sheet material.

The carbon content of the sheet material can vary over a very large range, depending on several factors, including the type and amount of carbon and / or flavoring material used, the location of the carbon-filled sheet material in the tobacco product, and the shape and structure of the sheet material. In general, the carbon content may range from 5 to 75% by weight of the sheet material, preferably from 10 to 40%, and most preferably from about 10,81,950 to 15%. Although higher amounts of carbon can be used, sheets containing more than about 75% by weight of carbon cause limitations in papermaking as well as limitations in paper properties, e.g., its tensile strength, very high dusting, and related problems.

Although both activated and inactive carbon can be used as the carbon component of the sheet material, activated carbon is preferred. As will be appreciated by those skilled in the art, there are numerous grades of activated carbon that are commercially available and can be used in accordance with the teachings of the present invention. For example, there are carbon-based, wood-based, and coconut-based activated carbons that are available from a variety of sources. One particularly preferred activated carbon, coconut shell based carbon, is PCB manufactured by Calgon Carbon Corporation, Pittsburg, Pennsylvania. This special carbon can be ground to different sizes. Although almost any particle size could be used in the sheet material of the present invention, preferred sizes range from about 250 to 600 U.S. Pat. mesh.

As will be appreciated by those skilled in the art, other adsorbent / absorbent agents may be included in the sheet material in addition to or instead of the carbon component of the sheet material. Such materials include tar, silica gel, zeolite, perlite, zeolite, activated alumina, magnesium silicate, and the like.

As mentioned above, the carbon-filled sheet material can be made using ordinary paper pulp. Preferably it is made from a mixture of wood pulp and tobacco pulp and stem pulp. The carbon component of the sheet material is generally added to the pulp of the pulp materials and their mixture and formed into a sheet using a conventional paper machine. The preferred sheet material is carbon filled tobacco paper treated by adding the desired amount of carbon to the tobacco pulp used to make the 81450 Kimberly-Clark tobacco of the P144-185-GAPF brand. Unmodified P144-185-GAPF contains about 60% tobacco, mainly flue gas dried / strong tobacco stems, and 35% softwood pulp (based on the dry weight of the substance). The moisture content of the unmodified sheet type material is preferably between about 11 and 14%. The tensile strength of the substance when dry is about 630 to 1300 g / cm, and the basis weight when dry is about 38 to 44 g / m 2. The substance is prepared using a conventional papermaking type process in which about 2% Glycerin or other wetting agent, about 1.8% potassium carbonate, about 0.1% flavorings and about 1% commercial adhesive are added. The adhesive is commercially available under the brand name Aquapel 360XC Ractive Size, from Hercules Corp., Wilmington, Delaware.

Flavoring agents can be incorporated into or on the carbon-filled sheet material in any of a number of ways, including, for example, spraying, dipping, printing, vapor deposition, and the like. Preferably, the flavoring agent is added to the sheet by a vapor deposition method. Vapor deposition is a procedure that typically involves heating a flavorant to a point where it is highly volatile and transporting the carbon-filled sheet material past or in contact with the vapors long enough for the desired amount of flavorant to be adsorbed / absorbed into the carbon-filled sheet material. In a preferred deposition method, called inner leaf transfer, the carbon-filled sheet material is contacted with an inner layer material. The inner layer material may be one of several materials, such as a heavy gauge coating, provided that its affinity for the flavor material is less than that of the carbon-filled sheet material of the present invention.

Another preferred method of adding a flavor to the sheet material comprises printing the flavor on the sheet material. Generally, printing involves passing the sheet material through a roll which rotates through a bath containing the flavor substance in question.

Another method of adding flavoring agents to carbon, either before or after it is added to the sheet material, will be apparent to one skilled in the art.

i2 81 950

A variety of flavoring agents, such as menthol, vanilla, artificial coffee, tobacco extracts, nicotine, nicotine salts, caffeine, spirits, coconut butter, and other substances that impart flavor to an aerosol produced in a tobacco product, may be used in the practice of the present invention. Other flavoring agents that may be used include those listed in "Tobacco Flavorings for Smoking Products", R.J. Reynolds Tobacco Company, Winston-Salem, North Carolina (1972).

The amount of flavor impregnated or otherwise contained in the sheet material can vary over a wide range, depending on the type of flavor, amount of flavor, carbon content of the sheet material, carbon activity, location of the sheet material in the tobacco product, manner of wrapping alpha ionone, it may be desirable to include as little as 0.00001% by weight of the sheet material. When menthol is a flavoring agent, the amount can range from 0.001% to saturation. In a preferred tobacco product, such as those described in Example I, the amount of menthol contained in the carbon-filled sheet material is between about 3-6%, most preferably between about 4-5%.

As mentioned above, in some preferred embodiments, the carbon-filled sheet material is located between the aerosol generating means and the mouthpiece side filter, and preferably forming a cylindrical filter plug. The sheet material can be formed into a cylindrical shape or other shape by conventional filter plug manufacturing methods, such as conventional plug making machines for making cellulose acetate tows.

13 81 950

Figure 3 illustrates one means for forming a carbon-filled sheet material in the form of a filter plug. As schematically shown in Figure 3, a roll 53 of flavored carbon-filled sheet material 50 is unwound and drawn into a tapered cone 54 for preforming, which "collects" or "folds" the sheet material 50 into a cylindrical shape suitable for a variety of cylindrical plug making machines. with different concentrations of carbon, flavor, etc., can be treated separately or simultaneously to provide a multi-compartment or layered flavor release means.This shaped cylinder 55 obtains wrapping paper 56 and the combination is cut to desired lengths 57 using knives 58. Continuous adhesive is added with an applicator before entering the device. to the other edge of the coating paper 56. As these components pass through the device, the formed cylinder 55 is further compressed into a rod with a cylindrical cross-section, at the same time ritään paper 56. When the bead of adhesive material contacts the remaining portion of the rod coverage, it is sealed closed jasauvalla. This endless cylinder rod is then cut to lengths 57 by a cutter 58.

Alternatively, it is preferred to use the double cone system shown in Figure 3A instead of a single cone 54. This system comprises a cone inside the second cone as a preforming device. The carbon-filled sheet material is fed into the annular space between the cones in a substantially stress-free state so that at the point of entry the sheet material rotates around the radial portion of the inner core. The cones can be moved relative to each other to provide the desired flatness and firmness of the cylinder body.

Although not essential for the manufacture of approved flavored carbon filled sheet material cylinders, flavorants may be added to the sheet material prior to its transformation into a cylinder body. The two treatments illustrated in Figure 3 may include a pair of i4 81950 grooved rollers 59 used for corrugation and a liquid spreader 60 used to surface treat the sheet material with, for example, menthol, glycerin or other flavoring or wetting agents.

In preferred embodiments where the carbonaceous sheet material is located between the aerosol generating means and the mouthpiece side filter in the form of a cylindrical body or plug, the length of the flavored carbonaceous sheet material body generally varies depending on the type and amount of flavoring agent used. In cigarettes using the preferred mouthpiece described in Example I, below, the length of the piece of carbon-filled sheet material is generally about 5 to 30 mm, preferably about 5 to 15 mm, and most preferably about 10 mm.

From a performance and / or aesthetic point of view, the firmness of a flavored carbon-filled sheet body used in accordance with the present invention can vary widely without substantially affecting the release of the aerosol to the user. However, it is desirable to have at hand a body that feels solid and has the firmness of a cigarette using a conventional cellulose acetate filter.

The overall pressure drop of tobacco products using the improved flavor release means of the present invention is preferably similar to or less than that of other cigarettes. The pressure drop in the carbon-filled sheet material and the filter media in the actual mouthpiece will vary according to the pressure drop in the front of the tobacco product. Preferred tobacco products, such as those mentioned in Example I below, generally have a lower pressure drop than conventional filter cartridges, usually in the range of about 0.1 to 6.0 cm water / cm filter length, preferably in the range of about 0.5 to 4.0 cm water / cm cm of filter length, and most preferably in the range of about 0.7 to 1.5 cm of water / cm of filter length. The pressure drop of the filter is the pressure drop in centimeters of water when 1050 cm / minute of air is passed through the filter plug. These pressure losses can be normalized per unit length of the filter plug by dividing the values by the length of that filter.

is 81950

Preferred tobacco products using the flavor release device of the present invention are described in the following patent applications: applicant_number_date

Sensabaugh et al., 650,604 14.9.84

Shannon et al. 684,537 21.12.84

Farrier et al., 769,532, 26.8.86

Banerjee et al. 939,203 8.12.86

Sensabaugh et al. EP 85111467.8 11.9.85 (published 19.3.86) Banerjee et al. EP 86109589.1 14.9.85 (published 4.3.87) The above publications are incorporated herein by reference.

One such tobacco product is illustrated in Figure 1, which is incorporated herein by reference. Referring to Figure 1, a cigarette having a low carbon fuel element 10 is illustrated through a plurality of, preferably about thirteen, passageways 11 arranged as shown in Figure 1A. In another preferred embodiment, a fuel element with eleven holes is used in the same manner as in the arrangement of Figure 1A, but with only five central channels in an "X" -shaped pattern. This fuel element consists of extruded carbon (preferably carbonized paper), sodium carboxymethylcellulose (SCMC) as a binder, K 2 CO 3, and water, as described in the aforementioned patent applications and EPO applications.

The circumference 8 of the fuel element 10 is surrounded by a flexible sheath of insulating fibers 16, such as glass fibers.

ie 81950

The metal capsule 12 covers a portion of the mouthpiece of the fuel element 10 and physically surrounds a separate aerosol generating means containing a substrate 14 with one or more aerosol-forming agents. The substrate may be in particulate form, in the form of a rod or in another form, as explained in the applications referred to above.

The capsule 12 is surrounded by a tobacco filler roll 18. Two slit-like channels 20 are arranged in the center of the tube shrunk in the capsule mouthpiece.

On the mouthpiece side end of the tobacco roll 18 is a mouthpiece 22, preferably comprising a cylinder body of a flavor-filled carbonaceous sheet material 24 of the present invention and a body of felt-like thermoplastic fibers 26 through which the aerosol passes to the user. The product, or part thereof, is provided with one or more layers wrapped on cigarette papers 30-36.

As mentioned above, the carbon-filled sheet material may be placed in one or more other non-combustible portions of the tobacco product. For example, the carbon-filled sheet material could be torn and placed in part of all or part of a roll of tobacco, or it could be used as one or more non-combustible wrappers that combine different parts of a tobacco product.

When the aforementioned cigarette is lit, the fuel element burns to generate heat which is used to evaporate the tobacco flavor and any other aerosol-forming substance or substances in the aerosol generating means and the tobacco roll. Because the preferred fuel element is relatively short, the hot combustible cone of fire is always close to the aerosol generating means, which maximizes heat transfer to the aerosol generating means and the tobacco roll, resulting in the production of aerosol and tobacco flavors, especially when using a preferred heat conductor. The hot gases, aerosol, and flavoring agents from the aerosol generating means and the tobacco roll heat the carbon-filled sheet material of the present invention that releases its flavoring agent.

i7 81 950

Due to the small size and combustion characteristics of the fuel element, the fuel element usually begins to burn over substantially its entire bare length within a few breaths. Thus, the portion of the fuel element that is close to the aerosol generating means heats up rapidly, which significantly increases the transfer of heat to the aerosol generating means and the tobacco roll, especially during the first and intermediate breaths. Because the preferred fuel element is so short, it never has a long proportion of non-combustible fuel that would act as a condenser, as was common in previous thermothermal aerosol products. This in turn raises the temperature applied to the flavor-filled carbon-filled sheet material, which probably raises the release of the flavor from the carbon component of the sheet. However, because the aerosol-forming agents and tobacco flavors and flavors in the carbon-filled sheet material are physically separate from the fuel element, they are subjected to substantially lower temperatures than the combustible fuel develops, minimizing temperature degradation of the flavors and aerosol-forming agents.

In a preferred embodiment, the short carbonaceous fuel element, the thermally conductive member, and the insulating member cooperate with the aerosol generating means and the tobacco roll to provide a system capable of producing a substantial amount of aerosol, tobacco flavor, and flavor from carbon-filled sheet material at virtually every breath. The location of the fire cone in the immediate vicinity of the aerosol generating means and the tobacco roll after a few breaths results in a high heat output with the insulating member during both the breaths and the glow times between relatively long breaths.

is 81950

In general, the combustible fuel elements that can be used in the preferred embodiment are no larger in diameter than the cigarette (i.e., 8 mm or less) and are generally less than about 30 mm in length prior to smoking. Preferably, the fuel element is about 15 mm or less in length, preferably about 10 mm or less. Preferably, the diameter of the fuel element is between about 2-8 mm, preferably about 4-6 mm. The density of the fuel elements used herein can generally range from about 7 g / cm 3 to 0.85 g / cm 3.

The material used to form the fuel element is preferably carbon. Preferably, these fuel elements have a carbon content of at least 60 to 70%, most preferably about 80% or more, by weight. High carbon fuel cells are preferred because they produce minimal pyrolysis and incomplete combustion products, little or no visible sidestream smoke, and minimal ash, and have a high heat capacity. Less carbonaceous fuel elements, e.g., those containing about 50 to 60 weight percent, may be used, especially when a smaller amount of tobacco, a quantity of tobacco extract, or a non-combustible filler is used. Preferred fuel elements are described in more detail in the aforementioned patent applications and EP publications.

The aerosol generating means is preferably located closer than 15 mm from the ignition end of the fuel element. The aerosol generating means may vary in length from about 2 mm to 60 mm, preferably in the range of 5 to 40 mm and most preferably in the range of about 20 to 35 mm. The diameter of the aerosol generating means may range from about 2 mm to about 8 mm, and is most preferably from about 3 to 6 mm.

· * Preferably, the aerosol generating means comprises one or more thermally stable substances containing one or more aerosol-forming substances. As used herein, a "thermally stable" material is one that can withstand high, i.e., controlled temperatures, e.g., in the range of about 400 ° C to 600 ° C, which can occur near fuel, without significant decomposition or combustion. The use of such a substance is believed to contribute to the maintenance of the simple "smoke" chemistry of the aerosol, as evidenced by the lack of Ames test activity in the preferred embodiment. Although not considered to be preferred, other aerosol generating means, such as heat-breaking microcapsules or solid aerosol-forming agents, may be considered within the scope of this invention provided that they are capable of releasing sufficient aerosol-forming vapors.

Persistent materials that can be used as a carrier or substrate for an aerosol-forming agent are well known to those skilled in the art. The useful substrate should be porous and should be able to retain the aerosol-forming compound when heated with fuel. Useful thermally stable materials include adsorbent carbons such as porous grade carbons, graphite, activated carbon inactivated carbons, and the like such as PC-25 and PG-60 available from Union Carbide Corp., as well as SGL carbon available from Calgon Carbon , Corp. Other suitable materials include inorganic solids such as ceramics, glass, alumina, vermiculite, clays such as bentonite, or mixtures thereof. Carbon and alumina substrates are preferred.

A particularly preferred alumina substrate is high surface area alumina (about 280 m 2 / g), such as the grade obtained from Davison Chemical Division of W.R. Grace & Co. marked SMR-14-1896. This alumina (-14 to +20 U.S. mesh) is preferably sintered for about an hour at a high temperature, e.g., above 1000 ° C, preferably between 1400 ° C and 1500 ° C, followed by suitable washing and drying steps prior to use.

20 81 950

The aerosol-forming agent or agents used in the present invention must be capable of generating an aerosol at the temperatures prevailing in the aerosol generating means as the combustible fuel element is heated. Such agents are preferably non-tobacco, non-aqueous aerosol-forming agents, and are composed of carbon, hydrogen, and oxygen, but may contain other agents. Such substances may be in solid, semi-solid or liquid form. The boiling or sublimation point of the substance and / or mixture of substances can be as high as about 500 ° C. Substances with these properties include: polyhydric alcohols such as glycerin, triethylene glycol, and propylene glycol, as well as aliphatic esters of mono-, di- or polycarboxylic acid such as methyl stearate, dimethyldodecandioate, dimethyl tetradecandioate.

Preferred aerosol-forming agents are polyhydric alcohols, or mixtures of polyhydric alcohols. More preferred aerosol formers are selected from glycerin, triethylene glycol and propylene glycol.

When the substrate is used as a substrate, the aerosol-forming agent may be dispersed in or on the substrate by any known method in a concentration sufficient to penetrate or coat the agent. For example, the aerosol-forming agent may be applied as such or as a dilute solution by immersion, spraying, vapor deposition, or the like. Solid aerosol-forming agents can be used among the substrate and evenly distributed prior to forming the final substrate.

Although the amount of aerosol-forming agent may vary from one substrate to another and from one aerosol-forming agent to another, the amount of liquid aerosol-forming agents may generally range from about 20 mg to 140 mg, and preferably in the range of about 40 mg to 110 mg. As much aerosol-forming substance as possible in the substrate should be released to the user in WTPM form. Preferably more than 2% by weight, even more preferably more than 15% by weight and most preferably more than 20% by weight of the aerosol-forming agent in the substrate is released to the user in WTPM form.

21 81950

The aerosol generating means may also contain one or more volatile flavoring agents, such as menthol, vanilla, artificial coffee, tobacco extracts, nicotine, nicotine salts, caffeine, spirits, and other substances that impart flavor to the aerosol. It may also contain any other desired volatile solid or liquid substances, such as those described in Leffingwell et al., Above. Alternatively, these additives may be placed in the mouthpiece, or in a preferred tobacco dose.

A particularly preferred aerosol generating means comprises the aforementioned alumina substrate containing spray-dried tobacco extract, levulinic acid or glucose pentaacetate, one or more flavoring agents, and an aerosol former such as glycerin.

A dose of tobacco can be placed downstream of the fuel element. In such cases, hot vapors pass through the tobacco by extracting and distilling the volatile parts of the tobacco, without combustion or substantial pyrolysis. Thus, the user receives an aerosol containing the flavors and aromas of natural tobacco, without the numerous combustion products produced in a conventional cigarette.

In a preferred embodiment, the thermally conductive material used as the reservoir for the aerosol generating means is typically a metal film, such as an aluminum film, having a thickness ranging from less than 0.01 mm to about 1.00 mm or greater. The thickness and / or type of conductive material can be varied (e.g., Grafoil, Union Carbide) to achieve the desired amount of heat transfer.

As shown in the embodiment illustrated in Figure 1, the thermally conductive member preferably contacts or covers the back of the fuel element and may form a container or capsule surrounding the aerosol generating medium of the present invention. Preferably, the thermally conductive member extends less than about half the length of the fuel element. Even more preferably, the thermally conductive member extends less than about 5 mm, preferably 2-4 mm, over the rear of the fuel element in contact therewith. Preferred recessed members of this type do not affect the ignition or combustion properties of the fuel element. Such members contribute to the extinction of the fuel element when it has been used up to the point where it contacts the conductive member which acts as a cooler. These bodies also do not protrude from the ignition head of the product even when the fuel cell has been used.

The insulating members used in the preferred tobacco products are preferably formed as a flexible sheath of one or more insulating layers. Preferably, this sheath is at least about 0.5 mm thick, more preferably at least 1 mm thick. Preferably, the jacket extends over at least half, even the entire length of the fuel element. Even more preferably, it also extends substantially over the entire periphery of the fuel element and the aerosol generating means. As shown in the embodiment of Figure 1, different materials can be used to isolate the two parts of the product.

Currently preferred insulation materials, especially for the fuel element, are ceramic fibers such as glass fibers. Preferred glass fibers include experimental materials produced by Owens - Corning, Toledo, Ohio under the designation C GLASS S-158, 6432 and 6437. Other suitable insulating materials, preferably non-combustible inorganic materials, may also be used.

To maximize aerosol release, which could otherwise dissolve in the radial (i.e., surrounding) air filtering through the product, non-porous paper can be used from the aerosol generating means to the mouthpiece.

23 81 950 Such papers are known in the cigarette and / or paper industry, and blends of such papers can be used for a variety of functional effects. Preferred papers used in the products of the present invention include: RJR Archer's 88-17234 paper; RJR Archer's 8-0560-36 Tipping with Lip Release Paper; Ecusta 646 Plug Wrap; and ECUSTA 30637-801-12001, manufactured by Ecusta, Pisgah Forest, North Carolina; and Papers P1768-182, P780-63-5, P850-186-2, P1487-184-2 and P850-1487-125 to Kimberley-Clark Corporation. The filter is preferably provided with a series of holes located about 23 mm from the mouthpiece of the tobacco product to provide about 22% air dilution.

The aerosol produced in the preferred tobacco products of the present invention is chemically simple, comprising substantially air, carbon oxides, an aerosol former containing any desired flavoring or other desired volatiles, water, and residues of other substances. The WTPM produced in the preferred products of the present invention has no mutagenic effects as measured by the Ames Test, i.e., there is no significant dose-response relationship between the WTPM produced by the preferred tobacco products of the present invention and the reversible substances present in the exposed products. standard test in micro-organisms. According to the authors of the Ames Test, a significant dose-dependent reaction indicates the presence of a mutagenic substance in the test product. See. Ames et al., Mut. Res., 31: 347-364 (1975); Nagao et al., Mut. Res., 42: 335 (1977).

Another advantage of the preferred embodiments of the present invention is the relative absence of ash produced compared to other cigarette ash. When the preferred carbon fuel element burns, it is substantially converted to carbon oxides, generating relatively little ash, and thus there is no need to remove ash when using the tobacco product of the present invention.

2 «81950

The use of the improved flavor release means of the present invention in cigarettes is further illustrated with reference to the following examples, which help to understand the present invention but are not to be construed as limiting it. All percentages given herein are by weight unless otherwise indicated. All temperatures are in degrees Celsius and have not been corrected.

EXAMPLE I

A cigarette of the type illustrated in Figure 1 was prepared as follows.

A. Fuel Source Preparation

A fuel element (length 10 mm, outer diameter 4.5 mm) with an apparent (total) density of about 0.86 g / cm 3 was made of carbon (90% by weight), SCMC binder (10% by weight) and (1% by weight) .

The carbon was prepared by carbonizing non-talc grade Grand Canadian Kraft hardwood paper under a nitrogen mattress, gradually raising the temperature by about 10 ° C per hour to a final carbonization temperature of 750 ° C.

After cooling the carbon under nitrogen to below 35 ° C, the carbon was ground to a particle size of mesh -200 (U.S.). The comminuted carbon was then heated to about 850 ° C to remove volatiles.

After again being cooled under nitrogen to below 35 ° C, the carbon was ground to a fine powder, i.e. a powder having an average particle size of 0.1 to 50.

This fine powder was mixed with Hercules 7HF SCMC (9 parts carbon: 1 part binder), 1% by weight K2CO3, and enough water to make it a rigid, doughy paste.

25 81950 From this paste, fuel elements were extruded with seven central holes, each about 0.53 mm in diameter, and six circumferential holes, each about 0.25 mm in diameter. The lattice thickness, i.e. the distance between the central holes, was about 0.2 mm, and the average outer lattice thickness (distance between the circumference and the circumferential holes) was 0.48 mm, as shown in Fig. 1A.

These fuel elements were then baked in nitrogen gas at 900 ° C for three hours after formation.

B. Spray-dried extract

The mixture of flue gas dried tobacco grades was ground to a medium fine dust and extracted with water in a stainless steel vessel at a concentration of about 0.1 to 0.15 g of tobacco per liter of water. The extraction was performed at ambient temperature using mechanical stirring for about 1-3 hours. The mixture was centrifuged to remove suspended solids, and the aqueous extract was spray-dried by continuously pumping the aqueous solution into a conventional spray-dryer, An-hydro Size No. 1, with an inlet temperature of about 215 to 230 ° C, and collecting the dried powder at the outlet of the dryer. The outlet temperature ranged from about 82 to 90 ° C.

C. Preparation of sintered alumina • y

High surface area alumina (area about 280 m / g) from WRGrace & Co with a particle size of about mesh -14 .. +20 (US) was sintered at a humidity of about 1400-1550 ° C for about an hour, washed with water and dried. This sintered alumina was combined in two steps with the substances in Table I in the proportions indicated: 26 81 950

Table I

Aluminum 68.11%

Glycerin 19.50%

Spray-dried extract 8.19% HFCS (invertose) 3.60%

0.60% for cocoa

Total: 100.0% The treated alumina was then dried to reduce the moisture content to about 1% by weight. In the second step, this treated alumina was mixed with the other substances listed above until the liquid was substantially absorbed into the alumina support.

D. Composition

The capsule forming the structure of the cigarette according to Figure 1 was made of deep-drawn aluminum. The capsule had an average wall thickness of about 0.1 mm, a length of about 30 mm, and an outer diameter of about 4.5 mm. The back of the container was closed except for two slit-like openings (each about 0.65 x 3.45 mm, about 1.14 mm) to allow the aerosol to enter the user. Approximately 330 mg of the aerosol-producing medium described above was used to fill the capsule. A fuel element prepared as described above was placed at the open end of the filled capsule to a depth of about 3 mm.

E. Insulating sheath

The fuel cell-capsule combination was wrapped from the end of the fuel cell in a 10 mm long glass fiber jacket of Owens-Corning C GLASS S-158 with 3% by weight pectin binder to form a diameter of about 7.5 mm. The fiberglass sheath was then wrapped in an inner wrapping material, Kimberley-Clark experimental paper, designated P780-63-5.

27 81 950 F. Roll of tobacco

A 7.5 mm diameter tobacco rod (length 28 mm), coated with Kimberley-Clark P1487-125 paper wrapper, was modified by placing a rod therein, about 4.5 mm in diameter, to form a longitudinal channel therein.

G. Composition

The jacketed fuel element-capsule combination was placed in the channel of the tobacco rod until the fiberglass jacket contacted the tobacco. The fiberglass and tobacco compartments were joined together with an externally wrapped material that covered both the fuel element / insulating jacket / inner coating combination and the wrapped tobacco rod. The outer wrapper was Kimberley-Clark paper marked P1768-182.

A mouthpiece of the type illustrated in Figure 1 was constructed by combining two compartments: 1) a 10 mm long, 7.5 mm diameter carbon filled tobacco sheet material near the capsule, wrapped in Kimberley-Clark paper P850-184-2 and 2) 30 mm long, 7 in diameter, A 5 mm cylindrical compartment of felt-like melt-extruded thermoplastic polypropylene web obtained from Kimberley-Clark Corporation, designated PP-100-F, and wrapped in Kimberley-Clark Corporation paper P1487-184-2.

The carbon-filled tobacco sheet material was prepared containing about 17% PCB-G activated carbon from Calgon Carbon Corporation in the paper used to make the sheet material and was obtained from Kimberley-Clark Corporation under the designation P144-185-GAPF. This substance would be provided with about 4.5% by weight of menthol flavoring by an inner layer transfer method. Both mouthpiece compartments were made by passing tuft paper and thermoplastic web fibers through a double cone forming system as described above. The two compartments were combined with a bonding coating wrapper Kimberley-Clark Corporation paper P850-186-2.

The combined mouthpiece portion was attached to the jacketed fuel cell - capsule compartment with a final coating wrapper

Ecusta 30637-801-12001 paper.

28 81 950 The cigarettes thus prepared produced menthol aerosol without any undesirable taste defects due to scorching or thermal deterioration of menthol or other aerosol-forming substances. Sensory comparisons comparing such products with commercially available low-tar menthol cigarettes showed similar results in terms of menthol taste detection and release.

EXAMPLE II

Cigarettes similar to those described in Example I were formed to study the migration of menthol from the source to the fuel source over a 10 day period under 24/40 humidity conditions (24 ° C and 45% relative humidity). All prototypes were equipped with approximately the same amount of menthol. For prototypes A and B, menthol was added directly to both the tobacco sheath and the aerosol-containing medium. Prototypes C and D contained menthol in Kimberley-Clark tobacco paper sheet P144-185-GAPF (sheet material made without carbon content) located between the aerosol generating means and the filter. With prototype E, menthol was placed on top of plastic-like beads obtained at Narrden Flavor House, Germany, under the brand name NFM. The beads were placed in a cavity made in the filter portion of the product. With prototype F, menthol was placed in an experimental fungicide obtained from Advanced Polymer Systems, designated DH-43-16, and incorporated into a P144-185-GAPF tobacco paper sheet (sheet material made without carbon content) placed in an aerosol generating device and product protection. between the data part. In the prototype G prepared according to the present invention, menthol was placed on a 10 mm long portion of the carbon-filled sheet material according to the present invention placed between the aerosol generating means and the filter.

29 81950

As can be seen in Figure 2, there is a substantial reduction in the migration of menthol into the fuel source of such products when menthol is placed in the carbon-filled sheet material of the present invention used in place of a normal tobacco paper wrapper.

Claims (13)

30 81 950 A tobacco product comprising: a fuel element (10), a physically separate aerosol generating means (12) comprising at least one aerosol generating agent, and separate means (24) for releasing an aerosol produced by the aerosol generating means to a smoker, characterized in that the release means (24) comprises carbon a sheet material containing at least one flavoring agent. Tobacco product according to Claim 1, characterized in that the carbon-filled sheet material is in the form of a cylinder. Tobacco product according to Claim 1, characterized in that the carbon-filled sheet material is torn. Tobacco product according to one of Claims 1 to 3, characterized in that the carbon content of the sheet material in percentages by weight is between about 5 and 75%. A tobacco product according to claim 4, characterized in that the carbon content of the sheet material in the weight percent is between about 10-40%. A tobacco product according to claim 4, characterized in that the carbon content of the sheet material in percentages by weight is between about 15-30%. A tobacco product according to claim 2, characterized in that the flavoring agent is menthol in an amount in the range of about 0.001% by weight until saturation. 31 81950 Tobacco product according to claim 7, characterized in that the amount of menthol by weight is between about 3 and 6%. Tobacco product according to claim 7, characterized in that the amount of menthol by weight is between about 4 and 5%. Tobacco product according to one of Claims 1 to 3 or 7 to 9, characterized in that the carbon-filled sheet material is tobacco-containing paper. A tobacco product according to claim 10, characterized in that the tobacco material has a tobacco content of about 65% by weight. A tobacco product according to claim 2, characterized in that the length of the cylinder of the carbon-filled sheet material is between about 5 and 30 mm. A tobacco product according to claim 12, characterized in that the length of the carbon-filled sheet material cylinder is between about 5 and 15 mm. 32 81 950