Patent Description:
Various types of leaf tobacco are used in smoking articles such as cigarettes, and by changing the type of leaf tobacco used, smoking articles that exhibit a variety of smoking flavors can be obtained. One known technique for adjusting the smoking flavor of cigarettes involves blending various types of shredded leaf tobacco having different smoking flavors.

The technique of blending different types of leaf tobacco includes, as described in Patent Document <NUM>, for example, a step in which a plurality of types of leaf tobacco raw materials separately subjected to processing such as vacuum treatment are each cut to produce cut filler leaf components, following which the cut filler leaf components are blended.

The invention described in Patent Document <NUM> indicates that, in the cutting treatment carried out therein, the cutting width is varied according to the type of leaf tobacco and the type of drying system, and should be set within the range of <NUM> to <NUM>.

Another known approach for imparting smoking flavor to tobacco involves, as described in Patent Document <NUM>, adding to tobacco or the like a paste-like material obtained by chemically treating citrus rinds.

<CIT> describes a method of producing a powdered tobacco extract that comprises extracting the soluble constituents from tobacco with a solvent, e.g. water, atomizing the solution and evaporating the minute droplets quickly with a hot gas to form a powder of the solute. The evaporation is carried out in a spray-dryer using hot air. The tobacco powder may be stored in containers for subsequent use as e.g. a coating to a web of paper or reconstituted tobacco. Preferably the web is formed from the non-soluble residue of the extraction process, this residue being formed into a tobacco web by a conventional paper making machine. The powder is made into a concentrated solution and coated on the web. The coated web may then by spray painted with a dispersion of finely divided tobacco in water.

<CIT> describes a method of preparing tobacco in sheet, web, or filament form that comprises subjecting the tobacco to a grinding or like reducing operation in water to reduce the tobacco to particles mainly of colloidal size and to form a colloidal dispersion of the particles in water, and subjecting the product to sheet, web, or filament forming and drying operations. The tobacco used may be in the form of whole leaves, fragments, stems, etc., or the waste from the manufacture of cigars, cigarettes, etc. It is dried, broken up in a shredding or other device and ground in a ball mill to fine powder. This is mixed with water for wet grinding in the same or a separate mill to form a colloidal dispersion without destroying the taste, odor and color of the tobacco. Instead of grinding first dry and then wet, the whole grinding may take place in the presence of water and may give a product containing some fibrous particles in the colloidal dispersion. These may be filtered out if desired. The product is extruded, spread or centrifugally applied to sheet-forming surfaces, for example, on an endless belt, the inner surface of a rotating cylinder, or iron or steel plates, which may be chromium-plated. The resulting film is dried by heat, a suction pump etc. in an atmosphere controlled as to humidity.

<CIT> describes formed tobacco products, such as flat or cord-like products, that are produced by (a) milling the tobacco with a liquid in a continuously operating mill; and (b) converting the finely milled product in a conventional manner into the desired form. The method gives formed tobacco products, such as cigarettes, cigars, and pipe-tobacco.

When smoking flavor is imparted to smoking articles, it is preferable for addition of the flavor to the smoking articles be carried out uniformly in such a way that the smoking flavor emerges evenly to the user.

In the art described in Patent Document <NUM>, the width of the cut leaf tobacco is in units of from several hundred microns to several millimeters. In cigarettes wherein such cut leaf tobacco has been blended, the cut leaf tobacco has a tendency to segregate within the cigarette according to the size of the cut strips.

For example, because the leaf tobacco in cigarettes is generally made up of strips of tobacco leaf that have been cut to a length of <NUM> to <NUM> and a width of <NUM> to <NUM> and has a fixed volume, mixing therein a very small amount of one type of leaf tobacco tends to give rise to unevenness. Specifically, given that ordinary commercially sold cigarettes contain an average of <NUM> strips of shredded leaf tobacco, mixing therein <NUM>% of one type of shredded leaf tobacco requires the uniform admixture of <NUM> strips of shredded leaf tobacco.

If this cannot be achieved, the smoking flavor of the cigarette may lack uniformity. In the method described in Patent Document <NUM>, the material that is added differs from tobacco, and thus cannot impart a smoking flavor distinctive to tobacco.

Accordingly, the object of this invention is to provide art which uniformly imparts a smoking flavor to tobacco products such as smoking articles.

The inventors have conducted extensive investigations, as a result of which they have discovered that a tobacco product having added therein a tobacco material containing leaf tobacco particles having an average particle size of <NUM> or less and a liquid dispersion medium for dispersing the particles, wherein the dispersion medium is a substance that is a liquid at normal temperature, wherein the weight ratio of the leaf tobacco particles, based on the total weight of the tobacco material, is from <NUM> to <NUM> wt%, and the leaf tobacco particles and the dispersion medium are included in the tobacco material in a combined amount, based on the total amount of the tobacco material, of at least <NUM> wt%, and wherein the tobacco product contains shredded tobacco, the tobacco material is applied to the shredded tobacco, and the weight ratio of leaf tobacco particles having an average particle size of <NUM> or less, based on the weight of the shredded tobacco, is from <NUM> to <NUM>%, can resolve the above problems in cigarettes.

The invention provides art for uniformly imparting a smoking flavor to tobacco products such as smoking articles.

The invention is described in detail below by way of embodiments, examples and the like.

The tobacco material includes leaf tobacco particles having an average particle size of <NUM> or less, and a dispersion medium for dispersing the particles; wherein the dispersion medium is a substance that is a liquid at normal temperature; wherein the weight ratio of the leaf tobacco particles, based on the total weight of the tobacco material, is from <NUM> to <NUM> wt%, and the leaf tobacco particles and the dispersion medium are included in the tobacco material in a combined amount, based on the total amount of the tobacco material, of at least <NUM> wt.

The leaf tobacco particles included in the tobacco material can be obtained by, for example, the following method.

No limitation is imposed on the types of tobacco that can be used as the leaf tobacco, although suitable use can be made of leaf tobacco raw materials from major varieties of tobacco such as flue-cured, burley, domestic and oriental tobaccos, and of fermented leaf tobacco obtained using such raw materials. As these leaf tobaccos, treated stem tobacco, expanded tobacco and sheet tobacco can also be used.

Because the above leaf tobaccos each have distinctive smoking flavors, there exists a desire for a method of uniformly adding very small amounts to smoking articles.

These leaf tobaccos are subjected to conventional drying treatment, following which they are coarsely ground using a conventional coarse grinding mill.

The drying treatment step and the coarse grinding step using a coarse grinding mill are not particularly limited, with the average particle size of the coarsely ground leaf tobacco falling in the range of from several hundred microns to several millimeters.

A liquid dispersion medium is added to the coarsely ground leaf tobacco, and these ingredients are mixed together by stirring.

The mixture obtained by such stirring and mixing is then finely ground using a wet fine grinding mill (e.g., MIC-<NUM>, available from Nara Machinery Co. The rotational speed of the machine is typically from <NUM>,<NUM> to <NUM>,<NUM> rpm, and grinding is carried out for a period of about <NUM> to <NUM> minutes.

By carrying out such operations, the leaf tobacco is ground to an average particle size of <NUM> or less.

When obtaining a dispersion of leaf tobacco particles dispersed in a liquid, use is generally made of a wet fine grinding mill, although the tobacco material can be obtained using even a dry fine grinding mill. Specifically, the coarsely ground leaf tobacco is finely ground to an average particle size of <NUM> or less using a dry fine grinding mill such as a jet mill, following which a liquid dispersion medium is added and stirring is carried out to effect mixture.

In this invention, the average particle size is a value determined by the laser diffraction-scattering method. The apparatus used is a laser diffraction-type particle size analyzer (e.g., the Shimadzu SALD-<NUM> Nanoparticle Size Analyzer), and the refractive index is set in the range of <NUM> to <NUM> i.

Using such measurement principles and instruments, the average value for the particle diameters obtained by analytic software supplied with the instrument is treated as the average particle size.

The leaf tobacco particles included in the tobacco material have an average size of <NUM> or less.

Because the finely ground leaf tobacco particles have this average size, the leaf tobacco particles in the tobacco material readily disperse evenly, making it possible to uniformly impart a smoking flavor to smoking articles.

The lower limit in the average particle size of the leaf tobacco particles is generally <NUM> or more, and may be <NUM> or more.

The average size of the leaf tobacco particles can be made larger by shortening the grinding time when using a fine grinding mill or by adjusting the dispersion medium to a low viscosity.

The dispersion medium may be one or more selected from among water, monovalent alcohols, polyvalent alcohols, sugar alcohols, sugars and polyvalent alcohol esters.

By using such a dispersion medium, the average particle size of the leaf tobacco can be adjusted to the desired value.

Illustrative examples of the dispersion medium include monovalent aliphatic alcohols such as methanol, ethanol, <NUM>-propanol, <NUM>-propanol, <NUM>-butanol, <NUM>-butanol, <NUM>-methyl-<NUM>-propanol, <NUM>,<NUM>-dimethylethanol and cyclohexanol; monovalent alcohols having an aromatic substituent such as benzyl alcohol; and also monovalent alcohols containing one or more halogen element, and monovalent alcohols having one or more ether bond.

In this invention, "polyvalent alcohol" refers generally to compounds having two or more hydroxyl groups on a single molecule and the types thereof are not limited. Examples thereof include glycerol and propylene glycol. Illustrative examples of sugar alcohols include sorbitol, maltitol, xylitol, erythritol, lactitol, sorbitan, xylose, arabinose, mannose and trehalose. Illustrative examples of sugars include lactose, sucrose, coupling sugar, glucose, enzyme-saccharified starch syrup, acid-saccharified starch syrup, maltose starch syrup, maltose, isomerized sugar, fructose, reduced maltose, reduced starch syrup, and honey.

Polyvalent alcohol esters are exemplified by fatty acid polyvalent alcohol esters. Examples of fatty acid polyvalent alcohol esters include fatty acid triglycerides.

The dispersion medium is a substance that is a liquid at a normal temperature.

Of the above, the use of water alone or of water in combination with a substance that dissolves in water is preferred.

Of these, the use of a mixed dispersion medium of water and glycerol is preferred from the standpoint of adjusting the average particle size of the leaf tobacco, when it has been finely ground, within the desired range.

No particular limitation is imposed on the mixing ratio of water with a dispersion medium other than water. When water and glycerol are used, these may be mixed in any ratio.

Tobacco products to which the tobacco material is added are not particularly limited, and are exemplified by smoking articles. Illustrative examples of smoking articles include cigarettes, cigar, pipe tobacco, hookah tobacco, and tobacco for Japanese kiseru pipes.

Because the tobacco material is obtained by dispersing the tobacco leaf particles in a liquid dispersion medium, the tobacco material can take the form of a slurry.

To have the tobacco material take the form of a slurry, the liquid dispersion medium and the leaf tobacco particles are mixed in a weight ratio of generally <NUM> part of leaf tobacco per <NUM> to <NUM> parts by weight of tobacco material, such that the leaf tobacco particles account for <NUM> to <NUM> wt% of the tobacco material.

In cases where the tobacco material is in the form of a slurry, the tobacco material is evenly and uniformly added to the smoking article by, for example, using a spray or the like to apply the tobacco material to the smoking article. In this way, the smoking flavor ingredients present in the tobacco material can be uniformly imparted to the tobacco product.

The tobacco material is applied to shredded tobacco.

When the tobacco material is to be added to cigarettes, it also may be added to cigarette paper, filter, tipping paper or the like which make up the cigarettes. Addition may be carried out at a single place, or may be carried out at two or more places such as at the shredded tobacco and the tipping paper each. Alternatively, it is also possible to impart differing smoking flavors during the smoking of a tobacco product such as a cigarette by adding tobacco materials obtained from different types of tobacco at different points on the cigarette paper.

In cases where the tobacco material is added to the filter of a cigarette, the tobacco material is impregnated into the filter.

The tobacco product contains shredded tobacco, to impart a desired smoking flavor to the tobacco product. The weight ratio of the tobacco material and the shredded tobacco is such that the weight ratio of leaf tobacco particles having an average particle size of <NUM> or less that are included in the tobacco material, based on the weight of the shredded tobacco, is from <NUM> to <NUM>%.

In cases where strongly flavored leaf tobacco is used in the tobacco material, a smaller weight ratio (e.g., about <NUM> to <NUM>%) may be employed.

No particular limitation is imposed on the variety of tobacco in the shredded tobacco to which the tobacco material is added.

Aside from the above-described particles of finely ground leaf tobacco, various additives may be added to the tobacco material. Illustrative examples include spearmint leaves, peppermint leaves and tea leave such as green tea for smoking flavor design, food ingredients such as coffee, cocoa, cardamom, menthol and sugar, polysaccharide thickeners such as glucan and pectin used to enhance dispersibility by adjusting the viscosity, food additives such as various types of emulsifiers, sizing agents such as carboxymethyl cellulose sodium (CMC), and curing agents for enhancing handleability following addition to leaf tobacco.

The timing in the addition of these additives is not particularly specified; addition may be carried out before finely grinding the leaf tobacco raw material so that the additives are finely ground together, or may be carried out to the slurry obtained after fine grinding.

These additives may be mixed with the leaf tobacco particles in any ratio.

The leaf tobacco particles having the above-indicated specific average particle size and the dispersion medium are included in the tobacco material in a combined amount, based on the total amount of the tobacco material, of at least <NUM> wt%.

The invention is described more fully below by way of examples. However, the invention is not limited to the following examples.

The following tests were carried out on smoking articles obtained using tobacco materials in order to determine whether the smoking flavor had been uniformly imparted.

Shredded tobacco used in commercially sold cigarettes was used in both Example <NUM> and Comparative Example <NUM>.

The average particle size of the leaf tobacco particles contained in the resulting tobacco slurry (tobacco material) was about <NUM>.

Shredded Latakia tobacco in amounts of <NUM> wt% or <NUM> wt% was added to commercial shredded tobacco and thoroughly blended. Cigarettes were produced using the resulting blended tobaccos. The sample names for the respective cigarettes thus obtained were K-<NUM> and K-<NUM>.

Controls were prepared by producing cigarettes using commercial shredded tobacco (in which shredded Latakia tobacco was not blended).

The samples evaluated were the following six types prepared as described above: K-<NUM>, K-<NUM>, S-<NUM>, S-<NUM>, S-<NUM> and S-<NUM>. Each sample was judged on a "Yes" or "No" basis as to whether the smoking flavor was uneven and whether, compared with the control, there was a change in the smoking flavor. The order of smoking is the order of the samples starting from the control. Evaluation was carried out by <NUM> male panelists (age, <NUM>±<NUM> years) who were instructed to take five or more puffs when smoking a cigarette.

The evaluation results are shown in Table <NUM> below.

Cigarettes were produced by rendering Latakia tobacco, which is one type of fermented leaf, into a slurry and spraying the slurry onto shredded tobacco (Example <NUM>). As a comparative product, cigarettes in which shredded Latakia tobacco was blended in a fixed ratio were produced (Comparative Example <NUM>). The smoking flavors of the cigarettes produced in Example <NUM> and Comparative Example <NUM> were checked by smoking the cigarettes, as a result of which it was possible to confirm that the cigarettes obtained by spraying on the tobacco material had a smoking flavor that was less uneven than the cigarettes obtained by the conventional blending method (involving the mixture of shredded tobacco with another type of shredded tobacco). It was confirmed from this that, even in cases where a small amount of the tobacco material was used, smoking flavor can be evenly imparted even to smoking articles such as cigarettes.

Hence, by making use of the tobacco material, subtle design in the smoking flavor of smoking articles is possible.

As in Example <NUM> and Comparative Example <NUM>, commercially sold shredded tobacco was used.

A <NUM> wt% menthol solution was prepared, and <NUM> of the solution was uniformly sprayed onto <NUM> of tobacco raw material. After spraying, the sprayed tobacco raw material was left to stand for at least one day to allow the menthol to blend in. The menthol concentration of this tobacco raw material was measured and found to be <NUM> wt%.

The tobacco raw material is referred to below as "shredded tobacco," and tobacco raw material flavored with menthol is referred to as "menthol-flavored shredded tobacco. Formation of Slurry from Menthol-Flavored Shredded Tobacco.

The average size of the leaf tobacco particles was <NUM>.

Menthol-flavored shredded tobacco was added in an amount of <NUM>, <NUM> or <NUM> wt% to shredded tobacco not flavored with menthol and thoroughly blended. Cigarettes were produced using the blended tobacco. The sample names for the respective cigarettes thus obtained were U-<NUM> and U-<NUM> and U-<NUM>. Analysis of Unevenness in Menthol Distribution.

As described above, a tobacco raw material to which menthol had been added was finely ground using a fine grinding mill, thereby preparing a tobacco material containing tobacco particles of the particle size specified in this invention. Cigarettes containing shredded tobacco that was sprayed with this tobacco material using a sprayer were then produced. In addition, cigarettes in which a tobacco raw material to which menthol had been added was blended (mixed) in a fixed ratio were produced as comparative products.

The menthol contents of these cigarettes were quantitatively analyzed by gas chromatography.

As shown in Table <NUM>, when the tobacco material was added to cigarettes, compared with cases in which a conventional blending method (in which one shredded tobacco is mixed with another shredded tobacco) was used, the variation in the menthol concentration among the individual cut pieces was very small, showing that the finely ground leaf tobacco raw material is evenly present in each of the cut pieces of the cigarette. In particular, even in cases where the amount of tobacco material added was small, the variation in concentration among the cut pieces was found to be small (the coefficient of variation was small).

This shows that, by using the tobacco material, subtle design in the smoking flavor of smoking articles is possible.

As in Example <NUM>, tobacco slurries (tobacco materials) were prepared using different types of leaf tobacco raw materials. The types of leaf tobacco raw materials and the treatment methods used are shown below in Table <NUM>.

The average particle size was determined using a SALD-<NUM> system from Shimadzu Corporation at a refractive index setting of <NUM> to <NUM> i.

By using a fine grinding mill to finely grind leaf tobacco under the conditions shown in Table <NUM>, tobacco slurries (tobacco materials) containing leaf tobacco particles having respective average sizes of from <NUM> to <NUM> were obtained. It was possible in all of the samples to obtain tobacco materials containing the leaf tobacco particles having an average size of <NUM> or less specified in this invention.

Claim 1:
A tobacco product having added therein a tobacco material;
the tobacco material comprising: leaf tobacco particles having an average particle size of <NUM> or less; and a dispersion medium for dispersing the particles; wherein the dispersion medium is a substance that is a liquid at normal temperature;
wherein the weight ratio of the leaf tobacco particles, based on the total weight of the tobacco material, is from <NUM> to <NUM> wt%,
and
the leaf tobacco particles and the dispersion medium are included in the tobacco material in a combined amount, based on the total amount of the tobacco material, of at least <NUM> wt%; and
wherein the tobacco product contains shredded tobacco, the tobacco material is applied to the shredded tobacco, and the weight ratio of leaf tobacco particles having an average particle size of <NUM> or less, based on the weight of the shredded tobacco, is from <NUM> to <NUM>%.