FI94385C - Concentric smoking filter with different blue and web-like filter media - Google Patents

Abstract

A concentric smoking filter (12) in which one of the filter media (20 or 21) is a fibrous tow, such as fibrous cellulose acetate tow, and one of the filter media (21 or 20) is a web material, such as paper, is provided. The filter improves the taste, particularly, of "ultra-light" cigarettes. <IMAGE>

Description

94385

Concentric smoke filter with separate baffle and web filtration materials

Concentrated filter filter with separate filter and filter media

The invention relates to smoke filters, in particular concentric smoke filters. More particularly, the invention relates to concentric smoke filters having concentrically arranged parts of tow and web filter media.

Most smoke filters, especially cigarette filters sold commercially as part of a cigarette, consist of a cylindrical herbal rod or "plug" formed of plasticized cellulose acetate fibers. Some filters are variants of this standard filter with a retracted mouthpiece or made of two end-placed plugs with either an empty space or a space filled with some other material such as carbon. It is also known to make filters with a plurality of adjacent plugs, these plugs differing in density or some other property.

. It is also known to use filtration materials other than cellulose acetate. One such material is a suitable sheet or web material. This web material from which the cylindrical stopper is formed may be paper or other web-like material, including sheet-like cellulose acetate. When such web materials are used as filters, they are usually crimped before forming the plug. Paper webs can also be creped to improve tensile strength.

Some such different materials and different structures have also been combined. For example, it is known to make filters with two or more contiguous 94385 2 plugs, at least one of which is a cellulose acetate herb, and at least one of which is a web material.

Finally, it is known to manufacture "concentric filters" in which a filter is formed from two different cellulose acetate tows which differ from one another, for example in density. One cellulose acetate herb forms a cylindrical "core", while the other herb forms an annular outer layer.

Such concentric filters have been shown e.g. in U.S. Pat. Nos. 3,369,061, 4, 355, 995 and DE 32 07 683.

The characteristics of cigarette filters are determined by various parameters, such as the pressure drop called "RTD", usually measured as the height of the water column, and the efficiency, measured as the percentage of total particulate matter (TPM) retained by the filter. The RTD value of a filter depends on how the smoker experiences the filter in terms of how strongly the cigarette must be sucked to obtain the desired amount of smoke, while the efficiency of the filter regulates the TPM content of the smoke.

'. It has been found that although web-like filters, especially paper filters, are more effective than soot filters, the web material, especially paper, still produces a sidestream taste in the smoke that reduces burner satisfaction. In addition, the appearance of visibly accumulated smoke components at the end of the paper filter is more irregular and smudged than in the cellulose acetate soot filter, which also adversely affects the aesthetic impression conveyed to the burner. Such a difference in appearance is assumed to be due to the channeling of the accumulating material into the channels resulting from the creasing and assembly of the web during the manufacture of the plug.

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As consumer preferences appear to be less and less focused on cigarettes releasing different substances, the need for more efficient filters that pass different substances released less from the cigarette without increasing filter suction resistance is increasing. There is a need to take advantage of the improved efficiency of paper filters while still avoiding the negative effects of paper filters on consumers. It would be desirable to provide an effective filter that is permeable to a small variety of substances so that the taste it produces, its absorption resistance, and the aesthetic impression it provides are acceptable.

The object of the invention is to provide a highly efficient filter which is permeable to only a small variety of substances while the taste impression it produces, its suction resistance and the aesthetic impression obtained from it are acceptable.

According to the invention, there is provided a smoke filter, the characteristic features of which are defined in the appended claims • c -, comprising a filter plug having a central core of first filter material and an outer layer of second filter material surrounding this central core. One of these first and second filter materials is a cellulose acetate tow and the other of these first and second filter materials is an aggregated crumpled web-like material. When this filter is attached to a cigarette product, and when it passes through the cigarette product when burning a certain total amount of particulate materials, the taste sensation obtained from the cigarette product corresponds to the taste associated with a total amount of particulate materials greater than this total amount.

The above and other objects and advantages of the invention will be apparent from the following detailed description and the accompanying drawings, in which like reference numerals refer to like parts throughout.

Fig. 1 is an oral end view of a cigarette, 4 Q Λ '1 G Γ, y -r JO j having a filter according to a first embodiment of the present invention;

Figure 2 is a radial cross-section of the filter of Figure 1;

Figure 3 is an oral end view of a cigarette having a filter according to another embodiment of the present invention;

Figure 4 is a radial cross-section of the filter of Figure 3;

Figure 5 is an oral end view of a cigarette having a filter according to a third embodiment of the present invention;

Figure 3 shows an oral end view of a cigarette having a filter according to a fourth embodiment of the present invention.

Within the scope of the invention, it has surprisingly been found that when a concentric filter is made of a core of paper or other web material and an outer cell of cellulose acetate. or vice versa, this not only achieves good filtration efficiency without producing a paper off-flavor, but also provides a cigarette with a small total amount of particulate matter released but with the same taste as a cigarette with a total amount of particulate matter released. . greater.

As shown in Figures 1 and 2, the cigarette 10 has a tobacco rod 11 and a filter 12 according to a first preferred embodiment of the invention. The tobacco rod 11 is wrapped in a conventional wrapper 13, while the filter 12 is wrapped in a conventional blotting paper 14. The filter 12 comprises a cellulosic

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5 9 4 3 ε ϋ the outer layer 20 of the acetate guide and the central core 21 of the paper. a manufacturing technique, such as steam bonding or spray coating of the outer surface of the outer layer 20, may be used, if desired, to make a filter that does not need to be covered inside the wrapper. The paper core 21 is a paper web that is crumpled and assembled into a single cylindrical shape and wrapped inside a stopper wrapping paper 23.

The plug wrap 23 improves the maneuverability of the core 21 as well as its aesthetic appearance, and allows a substantially complete concentricity to be achieved. Flavor or other additives, for example soluble components of tobacco, may be included in the stopper wrapper 23 to enhance the sensation of the filtered smoke. A similar result can be obtained by forming a stopper wrapper 23 of a tobacco-containing material, for example a sheet of modified tobacco. The plug wrapper 23 is preferably porous so that smoke and air can move freely between the outer layer 20 and the core 21. At the same time, the presence of the wrapper 23 contributes to preventing the passage of smoke along the interface between the outer layer 20 and the core 21.

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The filter 12 of the most preferred embodiment has a circumferential length of about 24.45 mm and an average weight of about 258 mg. The cross-sectional area of the core 21 is preferably about 60% of the total cross-sectional area of the filter 12. The suction resistance of the filter 12 is about 130-160 mm WG (water gauge), with the suction resistance of the central core 21 being about 350-450 mm WG. The suction resistance of the filter 12 is more preferably about 146 mm WG, the suction resistance of the central core 21 at about 400 mm WG

In a particularly preferred embodiment, the cellulose acetate tow forming the outer layer 20 is preferably 8.0 / 30,000 cellulose acetate tow having a thickness of 8 denier / fiber, a total of 30,000 denier, and having a cross-sectional shape of "Y". The web forming the core 21 is preferably 100% cellulose, semi-creped, softwood pulp paper with 10% cross-creping to improve tensile strength. Such paper is available from Tela Papierfabrik AG, Balsthal, Switzerland.

The aeration of the cigarette 10 is preferably about 65-75%, more preferably 67%, and is provided by suitable aeration holes 15 in the blotting paper 14. If the surface of the filter 12 is not permeable to air, then the filter 12 should also be provided with suitable holes.

Figures 3 and 4 show a cigarette 30 having a filter 31 according to another preferred embodiment, the structure of which is similar to that of the filter 12, except that the core 40 is of a herbal material and the outer layer 41 is of a web material. Also in this embodiment, the web material of the outer layer 41 must be wrapped inside the plug wrap 42, while the plug wrap or? the other permeable wrap 43 around the rudder core 40 is optional, as the rudder core 40 can be made as described above by a self-supporting filter rod fabrication technique.

The filter 31 of the most preferred embodiment has a circumferential length of about 24.45 mm and an average weight of about • 240 mg. The cross-sectional area of the core 40 is preferably about 60% of the total cross-sectional area of the filter 31. The suction resistance of the filter 31 is about 165-195 mm W. G., the suction resistance of the central core 40 being about 285-385 mm W. G. The suction resistance of the filter 31 is more preferably about 182 mm W. G., the central suction resistance. the suction resistance of the core 40 being about 334 mm W. G.

In this embodiment, the cellulose acetate conductor forming the core 40 is preferably 1.6 / 35,000 cellulose acetate conductors having a thickness of 1.6 denier / fiber, a total of 35,000 denier, and having a cross-sectional shape of "Y". The web forming the outer layer 41 is preferably the same, 100% cellulose 94385 7 (semi-creped, softwood pulp paper with 10% cross-creping to improve tensile strength used in the core 21 of the filter 12.

The aeration of the cigarette 30 is preferably about 65-75%, more preferably 67%, and is accomplished through suitable aeration holes 15 in the tissue paper 14, such as the aperture of the cigarette 10.

Figure 5 shows a cigarette 50 having a filter 51 according to a third preferred embodiment of the present invention. The filter 51 is a so-called "dual power" filter consisting of two adjacent filter blocks 52, 53. The filter block 52 adjacent the tobacco rod 11 is as described above. a concentric filter in which either the core 54 or the outer layer 55 is made of a web material, one of which being then a herbal material. The filter block 53 at the mouth end is a conventional herbal filter, for example a cellulose acetate filter, and is used mainly for cosmetic reasons.

• Nevertheless, block 53 has certain filtering and suction resistance properties, and block 52 must be adapted so that the entire filter 51 has the desired properties.

In the preferred case of this embodiment, the block .. 52 has a structure similar to the filter 12, but is only 18-20 mm long, while the block 53 is a 7-9 mm long plug formed of 2, 6/42000 cellulose acetate tow, in which is 2.6 denier / fiber, for a total of 42,000 denier, with a "Y" shape in cross section. The total suction resistance of the filter is about 125-175 mm WG, preferably about 141 mm WG The suction resistance of block 53 is about 15-45 mm WG, preferably about 36 mm WG The suction resistance of block 52 is about 85-175 mm WG, preferably about 93 mm WG The suction resistance of the paper core 54 of 52 is about 250-450 mm WG, preferably about 267 mm WG. with suitable aeration holes 15.

Fig. 6 shows a cigarette 60 having a filter 61 according to a fourth embodiment of the present invention. The filter 61 is a retracted filter consisting of a filter block 62 retracted into the blotting paper 14 at 63. The filter block 62 adjacent the tobacco rod 11 is a concentric filter as described above. , wherein either the core 64 or the outer layer 65 is a web material and one of them is a herb material.

The above filtration parameters have been obtained with an 85 mm long cigarette. It is clear that the filters according to the invention can also be used in longer cigarettes. If the cigarette is longer, the filtration parameters must be adjusted in a manner familiar to a person skilled in the art.

Example I

In the example, a filter according to the most preferred embodiment of the invention discussed above in connection with Figures 1 and 2 was prepared, except that the outer layer of the tow was 8.0 / 25,000 cellulose acetate tow with 8.0 denier / fiber and a total of 25,000 denier, and this filter was attached. very light "tobacco rod with the following characteristics: - tobacco 487 mg - total suction resistance 107 mm WG

- filter suction resistor 146 mm W. G.

. - degree of aeration 67% - length of blotting paper 32.0 mm.

The cigarette was burned in a burner under FTC conditions to give the following results:

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9 Q 'Z p r ✓ ~ r yj 0 W> - TPM 1, 8 mg - nicotine 0, 16 mg - water 0; 21 mg - "tar" 1.5 mg - suction 1km. 6.2

Expert smokers also smoked such cigarettes, which produce 1.5 mg of "tar", and reported that the taste of the cigarettes is equivalent to that of a cigarette producing 4-5 mg of "tar." At a degree of aeration of 67%, the efficiency of the filter was about 76%. In the absence of aeration, the efficiency would have been about 61%.

It was also found that the appearance of the retained material visibly accumulated at the end of the filter resembled the material retained on the strainer filter compared to the material collected on the web filter, although most of this retained material had accumulated on the surface of the web core. This is assumed to be due to the fact that the smoke enters the core 21 as the aerating air enters the cigarette through the holes 15 and then tends to spread back to the outer herb layer 20 through the permeable wrapper 23.

Example II

A filter according to a preferred embodiment according to Figure 5 .. was prepared and connected to a "very light" tobacco rod having the following characteristics: - tobacco 429 mg - total suction resistance 93 mm W. G.

- filter suction 141 mm W. G.

- degree of aeration 71% - length of blotting paper 32 mm.

The cigarette was burned in a burner under FTC conditions to give the following results: 10 G /. .7 P Γ.

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- TPM 1, 6 mg - nicotine 0, 13 mg - water 0.10 mg - "tar" 1.4 mg - suction 1km. 5.3

As in Example I, expert smokers were also allowed to smoke such cigarettes, and they found that the taste of the cigarettes corresponded to that of a cigarette producing 4-5 mg of "tar".

The filter according to the invention improves the taste of low-release cigarettes. It is also possible that the performance of the filter according to the invention is similar in the case of larger amounts of released substances. For example, a cigarette that releases a moderate amount of different substances can be experienced as a full-fledged cigarette.

Thus, it is stated that the invention provides a highly efficient filter which is permeable to a small variety of substances, but which still produces an acceptable taste and other aesthetic effects. It will be apparent to one skilled in the art that the present invention may be practiced in embodiments other than those described above, which seek to illustrate the invention without limiting it in any way. The invention is limited only by the following claims.

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Claims (19)

A smoking filter, which comprises a filter plug (12, 31, 52, 62) having a centrally located core (21, 40, 54, 64) of a first filter material and an outer layer (20, 41, 55, 65) surrounding the centrally located core and is of a second filter material, one of said first and second filter materials being fiber-blend and the other of said first and second filter materials being assembled corrugated web material, characterized in that the filter suction resistance is about 130-195 mm WG, while the suction resistance of the centrally located core (21, 40) is about 285-450 mm WG Smoking filter according to Claim 1, characterized in that the first filter material (21) is of said web-shaped material and the second filter material (20) is of said fiber-blank. A smoking filter according to claim 2, characterized in that the second material is cellulose acetate blend having about 8, 0 denier / filament and a total of about 25000-30000 denier, preferably about 30000 denier. The smoking filter according to claim 1, characterized in that the first filter material (40) is non-fibrous and the second filter material (41) is web-shaped material. The smoking filter according to claim 4, characterized in that the first fiber material is cellulose acetate blend with about 1, 6 denier / filament and a total of about 35000 denier. 6. A smoking filter according to any of claims 1-5, characterized in that the web-shaped material is paper. The smoking filter according to claim 6, characterized in that the paper has been creped before it has been corrugated and assembled. 94385 A smoking filter according to any of claims 1-5, characterized in that the web-shaped material is fiber-felt. 9. A smoking filter according to claim 8, characterized in that the fiber filter is sheets of cellulose acetate. A smoking filter according to any of claims 1-9, characterized in that the assembled corrugated web-shaped material is enclosed in a plug housing (23, 42). Smoking filter according to claim 10, characterized in that the plug housing (23) is porous. 12. A smoking filter according to claim 10 or 11, characterized in that the plug housing (23) contains flavor components. • <* 13. Smoking filter according to claim 12, characterized in that the plug housing (23) is a material containing tobacco, such as a sheet of reconstituted tobacco. '.4. Smoking filter according to Claim 12, characterized in that the plug housing (23) is plug-wrapping paper to which are added flavoring components, advantageously soluble components of tobacco. Smoke filter according to claim 1, 2 or 3, characterized in that its filtration efficiency is about 61% in unventilated form. Smoke filter according to any of the preceding claims, characterized in that its degree of ventilation is 65-75%. ΟΠΟΓ / ^ J 0 J Smoke filter according to any of the preceding claims, characterized in that the surface of the cut-through of the core (21, 40) constitutes about 60% of the total surface of the cut-through of the filter. Smoking filter according to claim 1, 2 or 3, characterized in that the suction resistance of the filter is about 146 mm W. G., with the suction resistance of the centrally located core (21) being about 400 mm W. G. 19. A smoking filter according to claim 1, 4 or 5, characterized in that the suction resistance of the filter is about 165-195 mm W. G., with the suction resistance of the centrally located core (40) being about 285-385 mm W. G. • <r r