SE500634C2 - fILTER TIP - Google Patents

Abstract

A filter cigarette includes a rod (1) of smokable material enclosed in a burnable envelope (2) and a filter connected to one end of the rod. The filter is a multi-component filter and includes one part (3) which contains activated carbon (6) and at least one part (4) which contains solely cellulose-based fibrous filter material, and is ventilated to a degree of ventilation of at least 50 %.

Description

15 20 25 30 35 40 5GB 6515- 2 material. Both of these general constructions are applicable to obtain a filter according to the present invention.

The mechanism of action of a multicomponent filter is believed to be that a portion of the aerosol particles are adsorbed to the surface of the fibrous filter material, after which their components are absorbed into the fibrous material. In the case of activated carbon, on the other hand, there is mainly an adsorption of gaseous components in the smoke.

Such a filter, built according to the two-component model, is known under the registered trademark CURZEL.

It is often sought to improve the degree of filtration of a cigarette filter by introducing so-called ventilation.

Ventilation means that small holes are made in the papers that enclose the filter or that these papers are made of air-permeable material. The ventilation causes secondary, diluting air to be sucked in through the air-permeable areas on the periphery of a cigarette filter while a flare is drawn on the cigarette, while a corresponding part of the total flare volume is drawn directly through the glow of the cigarette.

To a limited extent, the amount of undesirable components in the smoke from a cigarette can be reduced by using different types of tobacco or by using specially treated tobacco. Such measures give measurable changes in the amount of particulate smoke components, tar, while only marginal changes of the gaseous components are obtained.

According to the EC decision, a maximum amount of L5 mg - tar from cigarettes will be allowed from 1993 and in the Swedish market, cigarettes that emit 5 to 12 mg of tar are most common. However, there are a few brands with ultra-low smoke yields of down to 1 mg of tar. The amounts of tar can be determined by standard methods, such as ISO standards 3308 and 4387.

Despite the fact that a lot of work has been done to develop cigarettes that reduce the amount of unwanted components in the smoke, there is still a need for improvements in the area. The present invention now provides such improvements to a substantial extent.

According to the present invention there is provided a filter cigarette which comprises a smokable material enclosed in a combustible casing and a filter closed to the smokable material, characterized in that the filter is of 3 multicomponent type. The filter is either constructed as a two-component filter, with a component of cellulosic-based fibrous filter material and activated carbon, connected closest to the smokable material, and a component of cellulosic-based fibrous filter material without the addition of activated carbon, or the filter is constructed as a three-component filter , line a section containing activated carbon or the above-mentioned combination of fibrous filter material and activated carbon, which at each end is connected to a component of fibrous filter material without the addition of carbon particles.

All components of a filter construction according to the invention are cylindrical and have a circumference which is substantially equal to the circumference of the cylinder of smokable material.

Such a filter according to the invention is ventilated to a degree of ventilation of at least 50%, measured in measuring equipment commonly used for the tobacco industry.

The accompanying drawing schematically shows three different embodiments of a filter cigarette according to the invention. The three figures are longitudinal sections of a part of a filter cigarette at the mouth end. In the drawing figures, like details have the same reference numerals.

Figure 1 shows a part of a cigarette, which comprises a string of a smokable material 1, especially when tobacco, which is enclosed by a combustible casing 2. At the mouth end of the cigarette a filter is arranged, which comprises two filter components 3 and 4. The front filter component 3 here contains a fibrous filter material 5, denoted by zigzag lines, in admixture with grains of activated carbon 6, denoted by dots. The rear filter component 4, closest to the mouth end of the cigarette, contains only a fibrous filter material 7.

Figure 2 shows another embodiment, where the filter is built up of three filter components 8, 9 and 10. The front filter component 8 here contains only fibrous filter material 7, and the intermediate filter component 8 contains grains of activated carbon 6, but no fibrous filter material. .

The rear component 10, closest to the mouth end, contains only fibrous filter material 7.

Figure 3 shows a third embodiment, where the filter is built up of three filter components 11, 12 and 13. The front and 10 15 20 25 30 35 40 \! Ȁ 5056. 4 C the rear filter component 11, resp. 13 contains here only fibrous filter material in the same way as the embodiment shown in figure 2. The intermediate filter component 12, on the other hand, contains a mixture of fibrous filter material 5 and grains of activated carbon 6, in the same way as the filter component 3 in Figure 1.

The filter components in the various embodiments are ventilated to a total extent of at least 50%. For this, perforations can be arranged in the casing materials of the filter, or the filter casing can be made of a porous material. How the filter ventilation is to be arranged in detail is well known to those skilled in the art, and is not shown in detail in the drawing.

The smokable material is preferably tobacco, which can be processed according to current industry standards.

The material may also be provided with minor amounts of flavoring and flavoring additives, as well as other additives normally used in the cigarette industry. The tobacco may consist wholly or partly of specially treated tobacco, such as volume expanded tobacco or reconstituted tobacco.

The combustible cover consists mainly of cigarette paper of the usual type. However, it may consist wholly or partly of tobacco material, such as reconstituted tobacco. The casing may have been made naturally porous in the manufacture or provided with microscopic perforations after the material itself has been manufactured.

Filter cigarettes with a flammable casing of tobacco material are classified in some countries as "cigars" or "cigarillos". However, such products are also included in the present invention.

The filter connected to the combustible material is surrounded by paper, which has been made naturally porous in the manufacture or where one or more of the papers has been perforated, either during the manufacture of the paper or after the filter has been applied to the tobacco rod during cigarette manufacture.

These porous or perforated papers enclosing the filter allow ventilation of the filter when a flare is drawn on the cigarette during smoking, and the degree of ventilation is preferably at least 70% and may be as high as 80% or more, measured by conventional methods and equipment well known in the art. in the cigarette industry. 10 15 20 25 30 35 40 5 sno 634 In a particularly preferred embodiment, the smokable material consists of a tobacco material, and emits at the above ventilation intervals no more than about 5 mg of tar, determined by standard method, and the filter consists of either of the three multifilter constructions specified previously. .

The cellulose-based filter material may be any of those previously known for this purpose. In particular, the filter material consists of creped paper, regenerated cellulose or cellulose acetate fibers. Mixtures of cellulose-based filter materials can also be used.

Activated carbon can be used as one of the types of vegetable, mineral or animal origin that are common on the market. The carbon may have undergone various chemical or physical treatments to modify it in various ways, to improve general or specific adsorption properties. Coal of mineral origin, especially from coal, has been shown to give particularly advantageous results.

Analyzes have shown that a filter cigarette according to the invention gives a sharp reduction in the amount of gaseous smoking components, many of which are undesirable, which are released to the smoker. This reduction is surprisingly large in comparison with what is to be expected with knowledge of the state of the art. Use of the preferred filter described herein in a cigarette with a tar emission of about 6 mg per cigarette and a degree of ventilation of about 50% results in a reduction in the content of undesirable components in the gas phase of about 50% compared to the same reference cigarette which alone differs. in that the described filter has been replaced with a cellulose acetate filter. On the other hand, a use of the preferred filter according to the present invention with a degree of ventilation of about 80% and a tar emission of about 1 mg per cigarette reduces the content of undesirable components in the gas phase by as much as 78% compared to a cigarette with acetate filter alone but which is otherwise identical.

This large percentage reduction at a higher degree of ventilation and thus a lower tar emission is completely surprising. A person skilled in the art, with knowledge of the filter's performance on a cigarette with a lower degree of ventilation and a higher tar content, would possibly expect a reduction of no more than 50% of the volatile components in an increase in the degree of ventilation.

SUS 6É4 6 The solid smoke from the filter cigarettes according to the invention has been subjected to comparative tests with regard to levels of undesirable components in the gas phase, as well as with regard to cytotoxicity. These tests are described in more detail below: The test cigarettes and reference cigarettes contained the same tobacco material with a tar emission of about 1 mg / cigarette, a nicotine emission of about 0.2 mg / cigarette and a JO emission of about 1 mg / cigarette, determined by standard methods.

The filter for the cigarettes according to the invention consisted of two parts, one containing a mixture of cellulose acetate fibers and activated carbon derived from coal, and one containing only cellulose acetate fibers and located closest to the mouth end of the cigarette. The filters of the reference cigarettes contained only cellulose acetate fibers of the conventional type. The ventilation rate was 80% for both samples and the reference cigarette. 1. Chemical gas phase analysis The levels of a number of gas phase components belonging to different functional groups were determined quantitatively by means of high-resolution gas chromatography in a conventional manner. The following Table 1 shows the percentage reduction of the gas phase components for a filter cigarette according to the invention in relation to the reference cigarette.

Table 1 Chemical gas phase; Reduction of gas phase components (%) compared - with reference Chemical group (n = number of specific Reduction,% compounds within each group) Saturated hydrocarbons (n = 10) 52 Unsaturated hydrocarbons (n = 6) 75 Aromatic hydrocarbons (n = 3) 86 Aldehydes (n = 6) 71 Alcohols (n = 1) 66 Nitriles (n = 3) 90 N-heterocycles (n = 4) 95 Ketones (n = 11) 88 Mean (n = 44) 78 10 15 20 25 30 35 40 , 500 634 2. Cytotoxicity test The cytotoxicity was determined in a known manner by measuring the ability of cigarette smoke to induce the inhibition of colony formation ability in individual V79 cells from Chinese hamster lung (Jenssen, D. in: GJ Kilbey, M. Legator, W. Nichols and C .

Ramel (Eds) Handbook of Mutagenicity Test Procedures, Elsevier Science Publishers BV. Amsterdam (1984) p. 239-290).

The cytotoxicity was determined partly on fresh (non-condensed) gas phase and partly on fresh solid smoke. The results are given as an IC 50% value, ie. the number of flares of a cigarette which reduces the number of colonies formed by 50% in relation to an untreated control group. The results are shown in the following Table 2: Table 2 Biological tests of gas phase and solid smoke; Cytotoxicity in V79 cells Gas phase Full smoke Cigarette IC-50% value IC-50% value (flare) (flare) According to the invention 29.8 (0.2) 16.7 (2.2) Reference cigarette 11.0 (1 , 7) 8.5 (1.5) The results in the table show that the gas phase from the reference cigarette has almost three times as high cytotoxicity in this test as the gas phase from the cigarette according to the invention, while the whole smoke from the reference cigarette has substantially twice as high cytotoxicity in this test as the whole smoke from the cigarette according to the invention.

In summary, it has thus been shown that filter cigarettes according to the present invention, when compared with reference cigarettes, which differ only in the filter used, show a marked reduction in the content of undesirable components in the gas phase, and a markedly lower cytotoxicity of the gas phase. and full smoke. This means that the filter cigarettes according to the present invention represent a considerable technical advance over the state of the art.

This progress is quite surprising to those skilled in the art, since the percentage reduction of unwanted gas phase components 654 8 components is much greater than that obtained by comparing the corresponding filters on cigarettes with lower ventilation and higher tar emission, as shown above. With a more dilute gas phase, as obtained with higher ventilation, one would expect a lower percentage of separation instead of a higher one. This unexpected effect is obtained in filter cigarettes according to the present invention.

In the foregoing, the invention has been described with reference to a specific example of filter cigarette according to the invention. It should be noted, however, that the invention is not limited to this embodiment alone, but includes all conceivable variants and modifications within the scope of the patent claims.

Claims (8)

9 Patent claim 5 Û Û 6 E 4 A filter cigarette, comprising a string of smokable material, enclosed in a combustible casing, and a filter connected at one end of the string, characterized in that the filter is of the fl component type, and comprises a component containing activated carbon, and at least one component containing cellulose-based breast material, that the filter, mounted on a cigarette, is ventilated to a ventilation rate of at least 50%, and that the filter cigarette emits a maximum of 5 mg of tar in standardized smoke analysis. Filter cigarette according to claim 1, characterized in that the filter consists of a front component, which contains a cellulose-based filter material mixed with activated carbon, and a rear component, closest to the mouth of the cigarette, which contains only the filter filter material. Filter cigarette according to claim 1, characterized in that the filter consists of three components, a front component, which contains only the brittle filter material, an intermediate component, which contains only activated carbon, and a rear component, which contains only the brittle filter material. Filter cigarette according to claim 1, characterized in that the filter consists of three components, a front component, which contains only the brittle filter material, an intermediate component, which contains the brittle filter material in combination with activated carbon, and a rear component. , which contains only the ñbrosa ñlterternaterial. Filter cigarette according to one of Claims 1 to 4, characterized in that the activated carbon is of mineral origin, especially from coal. Filter cigarette according to one of Claims 1 to 5, characterized in that the smokable material consists of tobacco. Filter cigarette according to one of Claims 1 to 6, characterized in that the ventilation degree of the filter is at least 70%. 5 q; çf a _ v å ”.. 8. According to any one of claims 1-7, it is claimed that the cellulosic-based brittle material consists of wrapped paper, regenerated cellulose or cellulose acetate fibers.