EP2836089B1 - Cigarette paper that gives a cigarette a uniform drawing profile - Google Patents

Description

The present invention relates to a cigarette paper which imparts a uniform tensile profile to a cigarette made therefrom. It further relates to a method for producing such a cigarette paper, a cigarette and the use of a location-dependent concentration of a fire salt in a cigarette.

Background of the invention

A typical cigarette is made of tobacco, which is wrapped by the cigarette paper and together with it forms a typically cylindrical tobacco rod. The tobacco rod is followed by the filter, which typically consists of cellulose acetate fibers. The filter and tobacco rod are wrapped by the tipping paper. The tipping paper connects the filter to the tobacco rod. The cigarette paper has in addition to the function of wrapping the tobacco, among other things, the task of the cigarette to give an attractive appearance in the smoked and not hacked state and to influence the smoldering speed of the cigarette. It also serves to control the composition of the smoke, especially the content of tar, nicotine and carbon monoxide.

When smoking, the smoker creates a negative pressure at the mouth end of the smoldering cigarette, is sucked through the air on the one hand by the cone of embers on the cigarette holder, but on the other hand also flows through the air-permeable cigarette paper into the tobacco rod and so diluted the smoke. The stream of air flowing through the air-permeable cigarette paper into the tobacco rod during smoking is called strand ventilation.

In the case where the tipping paper is perforated, air flows through the tipping paper into the filter and also dilutes the smoke. This air flow is called filter ventilation.

The total dilution of the smoke is composed of the strand ventilation and the filter ventilation. However, when smoking and when glimmering free, the tobacco cord burns, so that its length decreases. As a result, the available area for the strand ventilation cigarette paper decreases, so that less and less air can flow through the cigarette paper in the tobacco rod and thus the strand ventilation decreases from train to train. To the same extent, the smoke is less dilute from train to train, and the concentration of the smoke-forming aerosols and gases in the smoke flowing from the mouth end increases. In addition, the tobacco rod has a certain filtration effect on the smoke, which is also decreasing with decreasing length of the tobacco rod. This gives the smoker the impression that the cigarette is getting "stronger" from train to train.

This impression is undesirable and various measures are known in the art to mitigate it. For example, the cigarette paper may be perforated with the portion of the cigarette paper close to the filter being more perforated and thus having a higher air permeability than the rest of the cigarette paper. As a result, the strand ventilation does not decrease as much as with cigarette paper with an approximately constant air permeability along the tobacco rod. However, this method sometimes has the disadvantage that such cigarettes are difficult to ignite because much air flows through the more perforated part of the cigarette paper and the air flow through the tip of the cigarette is too low to start the glowing process when lighting.

An alternative measure is to coat the cigarette paper on the part farther away from the filter so as to reduce the air permeability of the coated areas, thus first consuming portions of the tobacco rod which contribute less to strand ventilation, as in US Pat US 3,911,932 is proposed. Often, however, this measure leads to a disproportionate increase in the content of carbon monoxide in the smoke.

Furthermore, in the US 3,667,479 proposed to coat the cigarette paper in areas with strong oxidizing agents. When smoking, the paper is thermally rapidly degraded at the coated areas, and there are openings through which air can flow and dilute the smoke. The size or number of faces decreases in Towards the mouth end. The disadvantage is that such cigarettes have a very bad ash appearance. A cigarette is expected to remain as a white, closed column after smoking. Black spots, protruding ash particles or holes are undesirable. Due to the coating in partial surfaces, however, exactly such unwanted holes are created.

Finally, for example, in the US 3,805,799 also proposed multilayer coatings of degradable by the smoke and non-degradable substances. However, such solutions have found no distribution.

From the DE 10 2010 032 814 a cigarette paper is known which comprises a water-soluble salt which has lost more than 15% of its initial mass after heating to 230 ° C, the heating starting from a starting temperature of 30 ° C at a heating rate of 5 ° C / min under a Nitrogen flow of 25 ml / min takes place. The water-soluble salt may be contained in discrete strip-shaped portions.

Summary of the invention

Thus, there is still a need for opportunities to achieve a uniform draft profile, but avoid the disadvantages of the prior art, such as high content of carbon monoxide in the smoke, bad ash or inconvenience to the smoker when lighting the cigarette.

This object is achieved by a cigarette paper according to claim 1 and by a manufacturing method for a cigarette paper according to claim 9. Advantageous developments are specified in the dependent claims.

According to the invention, the cigarette paper is equipped with burn salts and designed so that the content of one or more Brandsalze in the cigarette paper from the filter end to the tobacco end changed on a cigarette made from it, in particular, that it changes monotonously within normal production and measurement tolerances, ie either monotonous increases or decreases monotonically. The change need not be strictly monotone, so there may be portions of constant content of the one or more Brandsalzes. The variable content or the variable concentration of Brandsalzen is chosen so that the cigarette paper gives a cigarette, in particular a filter cigarette, a more uniform tensile profile than would be the case for an otherwise similar cigarette with a constant Brandsalzkonzentration along the longitudinal direction of the cigarette.

The burn salts are substances, for example salts, which can increase or decrease the smoldering speed of the cigarette paper. Very commonly used are trisodium and tripotassium citrate and mixtures thereof. The group of Brandsalze, with which the invention can be implemented, but additionally includes citrates, malates, tartrates, acetates, nitrates, succinates, fumarates, gluconates, glycolates, lactates, oxylates, salicylates, α-hydroxycaprylates, bicarbonates, carbonates and phosphates and Mixtures thereof. Trisodium and tripotassium citrate are examples according to the invention of the flame accelerating, ie fire-promoting, Brandsalze, while phosphates can serve as the inventive example of the glow slowing, so fire retardant, Brandsalze. Whether a fire salt is fire-promoting or fire-retardant is generally known to those skilled in the art, or it can be easily determined by measuring the smoldering speed of a cigarette paper containing the fire salt in question in sufficient quantity.

wobei:

• 3 cm ≤L ≤ 11 cm,
• f(x) eine über dem Intervall [0, L] monotone, aber nicht über das gesamte Intervall konstante Funktion ist und
• Δc ≤ 1 Gew.-% vorzugsweise ≤ 0,7 Gew.-%, besonders bevorzugt ≤ 0,5 Gew.-%, ganz besonders bevorzugt ≤ 0,3 Gew.-% und insbesondere bevorzugt ≤ 0,15 Gew.-% und Δc>0 Gew.%, jeweils bezogen auf die Masse des Zigarettenpapiers, ist.

The influence of Brandsalzen on the Abrauchwerte is extremely complex and not fully understood in the field. However, the inventors have found that a more uniform pull profile can be achieved when the concentration c (x) of the at least one fire salt varies along a direction x of the cigarette paper,
where for the location-dependent concentration c (x) on an interval of length L for all x from the interval [0, L], $$f\left(x\right)-\mathrm{\Delta }\mathit{c}\le c\left(x\right)\le f\left(x\right)+\mathrm{\Delta }\mathit{c}$$

in which:

• 3 cm ≤ L ≤ 11 cm,
• f (x) is a monotonic over the interval [0, L], but not constant over the entire interval, and
• Δ c ≦ 1% by weight, preferably ≦ 0.7% by weight, particularly preferably ≦ 0.5% by weight, very particularly preferably ≦ 0.3% by weight and particularly preferably ≦ 0.15% by weight. % and Δ c > 0% by weight, based in each case on the mass of the cigarette paper.

By the concentration or Brandsalzgehalt in the paper, the mass of the anhydrous Brandsalzes based on the mass of the cigarette paper, as it is used on the cigarette, understood and expressed in wt .-%. The direction x of the cigarette papers may or may not necessarily be in accordance with the machine direction.

The length L corresponds to the length of the visible tobacco rod on the cigarette for which the cigarette paper is intended, ie the length from the point where the tobacco rod emerges under the tipping paper to the tip of the cigarette to be lit. This length L may be different for different types of cigarette but will be ≤11 cm and ≥3 cm in the bars. The function f (x) is monotone over the interval [0, L], but does not necessarily have to be strictly monotone. On the contrary, some of the presently preferred embodiments have near-end and near-tip portions having a uniform or substantially uniform concentration c (x) of the burnt salt. In any case, the function f (x) is not constant over the entire interval.

Furthermore, the actual concentration c (x) of the fire salt may deviate from the monotone function f (x) by a value of Δ c . This value Δ c takes into account the usual production and measurement tolerances of Brandsalzgehaltes. Furthermore, Δ c defines a certain corridor about an idealized curve f (x), which still allows an improvement over a constant Br of salt concentration, but possibly deviates locally to a moderate extent from the ideal monotonous course.

Since the influence of Brandsalzen on the Abrauchwerte is comparatively complex and not completely understood, the expert will determine the most suitable variation of the Brandsalzgehaltes experimentally in many cases. However, extensive research by the inventors has shown that, in fact, in many cases, the above-described monotonous or nearly monotonous course of the fire salt concentration gives good results will deliver. It turns out surprisingly that both those location-dependent concentrations c (x), in which the concentration increases from the filter end to the cigarette holder, as well as those in which the concentration from the filter end to the cigarette tip decreases, compared to a uniform distribution of the fire brine improved Train profile can cause. In this respect, the invention indeed defines a class of cigarette papers which have the potential to substantially homogenize the tension profile.

This technical effect can be explained at least qualitatively. It is known that burn salts, which are applied to the cigarette paper at a constant level, influence the smoking values of this cigarette. The relationship between the content of Brandsalzen and the Abrauchwerten depends on the type of Brandsalzes and can be easily determined by the expert in a specific case. Usually, the relationship is nonlinear.

For a significant group of brine salts, in particular for trisodium and tripotassium citrate, the following typical behavior is found in such experiments: If the content of the Brandsalz is increased from a cigarette paper without brominated salt, the values of exhaustion are initially reduced. This reduction is probably at least partially caused by the fact that the cigarette smoldering faster and therefore less trains are taken. Which mechanisms cause exactly this reduction is unknown to the inventors.

If the content of the firing salt is further increased, the exhaustion values fall less and less and, with a certain content of the firing salt, reach a minimum. For papers with citrates as the fire salt, the minimum for tar and nicotine is typically at a fire salt content between 1.5% and 5.0% by weight, for. Trisodium citrate typically at a Brandsalzgehalt of 1.5 wt .-% to 3.0 wt .-% and for tripotassium citrate at 3.5 wt .-% to 5.0 wt .-%, each based on the mass of the cigarette paper, so as it is used on the cigarette. With a further increase in the fire salt content, however, the levels of smoke are beginning to rise again. Despite increasing smoldering speed and therefore further decreasing number of trains, the content of tar and nicotine increases both overall and per train. In part, this may be due to the fact that the accelerated glow even with a train burns more paper and therefore parallel to it the amount of tobacco consumed per move increases. However, even here the mechanisms are not exactly clarified.

According to the invention, this complex behavior is now exploited by selecting the interval and the course of the content of the fire salt along the tobacco rod so that the normally increasing from train to train exhaustion values are compensated by the course of Brandsalzgehalts.

For example, for trisodium or tripotassium citrate this can be done in at least two ways. A first possibility is to choose the content of the Brandsalzes at the filter end of the cigarette near the value at which - with an otherwise equal cigarette but with constant Brandsalzgehalt - a minimum tar and nicotine would be achieved and the content of the Brandsalzes then in the direction of to be lit end of the cigarette monotonically or at least approximately monotonically.

A second possibility is to choose the content of the Brandsalzes at the filter end of the cigarette again close to the value at which a minimum tar and nicotine is achieved, but then to increase the content of the Brandsalzes in the direction of the end of the cigarette to be ignited.

In both cases, the Brandsalzgehalt, which - with a constant Brandsalzgehalt - to minimal tar and nicotine values leads near the filter end of the tobacco rod, ie in a range of the cigarette, which produces the "strongest" features when smoking, while those Brandsalzgehalte, the - At constant Brandsalzgehalt - lead to higher levels of smoke in the vicinity of the lit end of the cigarette, ie where the trains are rather "weak". A "strong" or "weak" train is understood to mean that the levels of exhaustion of tar and nicotine are higher or lower this turn relative to the other strokes on the same cigarette. In both cases, there is a change over the length of the tobacco rod monotonous change in the Brandsalzgehaltes or the Brandsalzkonzentration, but with the opposite slope. In this respect, the monotonous or at least approximately monotonous Brandsalzkonzentrations courses actually define a universal class of Brandsalzprofilen that can be achieved with uniform traction profiles. This can also be confirmed experimentally.

If a mixture of at least two different Brandsalzen present in cigarette paper, the total content of Brandsalzen in cigarette paper, be constant, but is preferably, depending on which Brands salt outweighed in its effect on the Zugprofil, decrease or increase from the filter end to the tobacco end.

For the monotone function f (x) , preferably | f ( L ) - f (0) | ≥ 0.5 wt .-%, preferably ≥ 1.0 wt .-% and particularly preferably ≥ 2.0 wt .-%. Preferably, | f ( L ) - f (0) | ≥ 2Δ c .

As mentioned above, L corresponds to the length of tobacco rod visible on the associated cigarette, ie, the length from the point where the tobacco rod emerges from under the tipping paper to the tip of the cigarette to be lit. The variable x may then be understood as a location coordinate extending along the tobacco rod from the point where the tobacco rod emerges below the tipping paper x = 0 to the tip of the cigarette to be lit, x = L.

A preferred course of the content of at least one Brandsalzes starting from the filter end of the visible tobacco rod, x = 0, in the direction of the end of the cigarette to be lit, first an optional range in which the content of the Brandsalzes is constant, then followed by a linear increase or decrease of the content, and finally again an optional range with constant Brandsalzgehalt.

für alle x aus dem Intervall [0,L] erfüllt sind, mit $$f\left(x\right)=\{\begin{array}{cc}{c}_0& 0\le x\le L_1\\ c_0+\left(c_L-c_0\right)\frac{x-L_1}{L_2-L_1}& L_1<x<L_2\\ c_L& L_2\le x\le L\end{array}$$

wobei für c₀, c_L, L₁ und L₂ wie im Folgenden erläutert spezielle Werte zu wählen sind.Expressed in an equivalent form, the cigarette paper is therefore preferably designed so that for at least one fire salt with the content c (x) at the position x the inequalities $$f\left(x\right)-\mathrm{\Delta }\mathit{c}\le c\left(x\right)\le f\left(x\right)+\mathrm{\Delta }\mathit{c}$$

for all x from the interval [0, L] are satisfied, with $$f\left(x\right)=\{\begin{array}{cc}{\mathrm{<figure-callout\; id="0"\; label="c"\; filenames="imgf0001.png"\; state="\{\{state\}\}">c</figure-callout>}}_0& 0\le x\le L_1\\ c_0+\left(c_L-c_0\right)\frac{x-L_1}{L_2-L_1}& L_1<x<L_2\\ c_L& L_2\le x\le L\end{array}$$

wherein for c ₀ , c _L , L ₁ and L ₂ , special values are to be selected as explained below.

The values L ₁ and L ₂ should be set so that the rise or fall is neither too steep nor too late to begin or end. The upper limit for L ₁ is 2L / 3, preferably L / 2 and more preferably L / 3 has proven. The lower limit for L ₁ is 0, and preferably L / 6. Likewise, the Lower limit for L ₂ with L / 3, preferably L / 2 and more preferably 2L / 3 to choose. The upper limit for L ₂ can usually be set at L, preferably at 5 L / 6. In general, however, it must always be true that L _{1 is} less than or equal to L ₂ .

Although by means of a sudden change in the Brandsalzgehalts, ie L ₁ = L ₂ , the invention can be realized in principle, this embodiment is not preferred. It is better to choose the length of the increase or decrease of Brandsalzgehalts, L ₂ -L ₁ , greater than L / 6, preferably greater than L / 3 and more preferably greater than L / 2. Of course, the length of the rise or fall, L ₂ -L ₁ , on the cigarette can not be greater than the length of the visible tobacco strand, so that L defines an upper limit for the difference L ₂ -L ₁ . Preferably, however, it is possible to provide a constant Brandsalzgehalt near the filter, since this area of the cigarette is hardly smoked anyway. Similarly, one can also provide a range of constant Brandsalzgehalts at the end of the cigarette to be lit, since this area burns in one step when lighting and thus affects the tension profile little. A preferred upper limit for the length of the increase or decrease, L ₂ -L ₁ , is therefore 9L / 10, and more preferably 4L / 5, and most preferably 2L / 3.

The values for c ₀ or c _L should be greater than or equal to 0% by weight, preferably greater than 0.2% by weight and particularly preferably greater than 0.5% by weight. With regard to the upper limits for c ₀ and c _L , 15% by weight is a possible choice, but 10% by weight and more preferably 7% by weight are preferred. If the at least one fire salt, the content of which changes on the cigarette paper, is a citrate, 5% by weight has also proved to be a very particularly preferred upper limit. These ranges apply to c ₀ and c _L independently of each other. However, it must always be true that c ₀ is different from c _L , ie that there is actually a change in the fire salt content, and preferably the amount of the difference c ₀ -c _{L is} greater than 2Δc. The value for Δc again preferably corresponds to the abovementioned values.

There are no restrictions on the geometric distribution of the burn salts on the cigarette paper. With regard to the content of the at least one Brandsalzes at a position x is always to understand its average content in the circumferential direction on the cigarette on a strip of width L / 10 with the position x in the middle of the strip. The For a measurement of the content of Brandsalzen at the position x required sample amount of the paper, for example, about 1 g, you will usually have to remove from several cigarettes, usually about five to ten cigarettes. Suitable methods for the determination of acetates, citrates or phosphates in cigarette paper can be found, for example, in CORESTA Recommended Methods 33, 34 and 45.

Preferably, the cigarette paper is designed so that it can produce cigarettes, which have within the production and measurement tolerances the nominally same course of the content of at least one Brandsalzes along the visible tobacco rod. This may mean, for example, that the cigarette paper is provided with one or more markings which allow the cut of the tobacco rod to be synchronized with the course of the fire salt content, whose positions are thus in a predetermined local relation to the curve c (x) of the fire salt content. The markings are preferably detectable by their action on electromagnetic waves, that is, for example, transmission, reflection, refraction or absorption of visible light, ultraviolet light or infrared radiation, and more preferably by an optical sensor, in particular an optical sensor which responds to reflected visible light to be detected. Preferably, these markers are mounted on the cigarette paper so that they come to lie on the finished cigarette under the tipping paper and thus are not visible to the smoker.

One possible method is to slightly color the composition with the one or more branding salts applied to the paper and to apply a fine but easily detectable line or other mark at the location where the tipping paper overlaps with the cigarette paper , Preferably, one will imprint the line or marking on the later side facing away from the tobacco, so that after production of the tobacco rod, the line or mark remains detectable for an optical sensor. Generally that's the top of the cigarette paper. It is also possible to place the line or mark on the tobacco-facing side of the cigarette paper, but then it is advisable to detect the line or mark on the cigarette paper before the tobacco rod is formed on the cigarette machine.

Preference is given to the fact that on commercial cigarette machines first made a double cigarette, then cut and then one of the two halves is turned to take into account in the design of the course of the content of at least one Brandsalzes consideration. This may mean that the course of the fire salt content c (x) along the running direction of the cigarette paper is periodically alternately applied, optionally with suitable spacing, in the normal and in the reverse direction, so that after cutting the double cigarette the Brandsalzprofil on the visible part of the tobacco strand at nominally equal to all cigarettes.

The invention can also be applied to cigarettes which contain no filter. In this case, the position x = 0 is the mouth end of the cigarette and x = L, the end of the cigarette opposite the mouth end.

As regards the choice of base cigarette paper, d. H. the starting cigarette paper, which according to the invention is to receive the location-dependent Brandsalzkonzentration, there are no restrictions, so that all known from the prior art cigarette papers can be used for the realization of the invention, including colored papers or papers with treated areas, which serve the self-extinction of a cigarette made thereof can.

Base cigarette papers preferred for the invention consist of pulp fibers derived from wood, flax, hemp, esparto grass or other materials. Mixtures of pulp fibers of various origins can also be used. Preferred base cigarette papers have a basis weight of 10 g / m ² to 60 g / m ² , with the range of 20 g / m ² to 35 g / m ^{2 being} particularly preferred.

The preferred base cigarette paper also contains inorganic mineral fillers which are added to the paper in a mass fraction of 10% to 45%. A particularly preferred filler is lime (calcium carbonate), but other oxides such as magnesium oxide and aluminum hydroxide and carbonates and mixtures thereof can also be used. Precipitated lime is preferred over geologically degraded lime for its purity and more uniform particle size. Cigarette papers without filler or with less than 10% filler are also common and conceivable for the invention, especially for non-machine-made cigarettes ("roll-your-own", "make-your-own"). Likewise are Cigarette papers with more than 45% filler known, however, decreases with increasing filler content, the strength of the paper, and the paper tends to release dust during further processing, which is why this design is not preferred for use in machine-made cigarettes.

An important factor for the characterization of the cigarette paper is its air permeability. It is measured according to ISO 2965 and expressed in cm.min ^-1 .kPa ^-1 . The preferred base cigarette papers in the context of the invention have a natural air permeability, ie without further perforation, from 0 cm.sup.- ¹ kPa.sup.- ¹ to 350 cm.sup.- ¹ kPa.sup.- ¹ , preferably between 20 cm.sup.- ¹ kPa.sup.- ¹ and 200 cm min ^-1 kPa ^-1 and more preferably between 30 cm min ^-1 kPa ^-1 and 120 cm min ^-1 kPa ^-1 .

By perforation or other measures, the air permeability can be significantly increased, for example, over 300 cm min ^-1 kPa ^-1 or even over 1000 cm min ^-1 kPa ^-1 .

Cigarette papers are typically made in rolls of, for example, between 0.3m and 5m widths and cut into reels having a cigarette circumference derived width, typically 9mm to 35mm, or an integer multiple of that width.

The known from the prior art treatment of the cigarette paper with Brandsalzen comprises impregnation of the paper on the paper machine in the size or film press with a water-based solution of the Brandsalzes and subsequent drying. Also a soaking of the paper on a separate downstream of the paper machine device is conceivable.

Likewise, methods are known in which an aqueous composition with a particularly high Brandsalzkonzentration is applied over the entire surface and uniformly on the overdried paper by means of a flexographic printing unit integrated in the paper machines and the paper is then rolled directly without further drying.

These processes lead to a nominally constant content of burn salts over the entire paper surface and are not applicable to the subject invention without further modifications. But you can serve the cigarette paper first to equip it with a constant Brandsalzgehalt over the area, so that afterwards by further steps the desired course of Brandsalzgehalts can be produced. For example, a later plotted history of the Brandsalzgehalts could be superimposed on this achieved by soaking or printing constant Brandsalzgehalt. The reverse sequence of the sequence is conceivable, ie, first an order of the course and then an impregnation or printing of the cigarette paper, which is less preferred because the wetting of the paper when soaking or printing the previously applied profile can be changed.

Preferably, the at least one fire salt is applied to the base cigarette paper in the form of a liquid composition, especially a solution, suspension or other form of mixture in a solvent. This order can preferably be achieved by a printing process or by spraying.

In order to produce the desired course of the Brandsalzgehalts as accurately as possible, the single-layer application is preferred over a multilayer.

The printing process can be formed by gravure printing or flexographic printing. In the case of gravure printing, a gravure cylinder is preferably provided with wells, from which the composition to be printed is transferred to the base cigarette paper, wherein the volume of the wells and / or the density of the wells on the gravure cylinder, which is also referred to as "grid size of the wells" can, is or is chosen so that the desired location-dependent concentration c (x) of the Brandsalzes results.

Since many substances used as Brandsalze are water-soluble, the modification of a constant Brandsalzgehalts, as it arises, for example, by impregnation in the size press, conceivable. Such modification may be effected by deliberately applying water to the paper to release burn salts from the paper or to move within the paper. The application of water can be done on a downstream of the paper machine, separate device.

In one embodiment, this process is used to modify a possibly even constant course of the content of at least one fire salt which is already present in the cigarette paper.

Other processing steps, such as printing on self-extinguishing tapes known in the art, may be carried out before, after or simultaneously with such treatment of the paper to create or modify a history of fire salt content.

The composition used to prepare the history of the fire salt content comprises at least one fire salt and a solvent. The term solvent should not be considered as limited to solutions in the chemical sense. The fire salt may also be in suspension in a suspension or other form of the mixture in the solvent. In general, water is preferred as a solvent over organic solvents because it leaves no trace of the taste of the cigarette in the paper and is safe in terms of fire hazard.

The content of the Brandsalzes in the composition is at least 0.1 wt .-%, preferably at least 1 wt .-% and particularly preferably at least 2 wt .-%, and at most 15 wt .-%, preferably at most 10 wt .-% and particularly preferably 7% by weight, where the statements are to be understood as the mass of the anhydrous Brandsalzes based on the mass of the finished composition.

Optionally, the composition, for example, for adjusting the viscosity, other substances, in particular polymers individually or in any mixture, included. Examples of such polymers are cellulose derivatives, such as carboxymethyl cellulose, polysaccharides, such as starch or starch derivatives, or in particular also alginates, dextrins, guar or gum arabic. Such substances may be required, for example, for chromium-plated steel printing cylinders for intaglio printing in order to produce a film on the printing cylinder by the adapted viscosity so that the doctor applied to the printing cylinder does not scratch the printing cylinder. In the case of ceramic-coated printing cylinders, such substances may possibly be omitted in the composition. The viscosity of the composition can be characterized by the flow time, and it will, for example, for the gravure between 10 s and 40 s, preferably choose between 12 s and 35 s, measured as flow time from a cup with an opening of 4 mm according to ÖNORM EN ISO 2431: 2011. The measurement of the flow time should be done at the temperature at which the composition is used in the application process.

In order to achieve a certain content of the at least one Brandsalzes in the cigarette paper, the applied amount of the composition on the initial basis weight of the cigarette paper, ie on the basis weight before the application of the composition must be coordinated. The applied amount of the composition should be at most 100% of the starting surface weight, preferably at most 80%, and more preferably at most 60%. Above all, the upper limits result from the amount of composition which can be applied to a cigarette paper without significantly impairing its processability, for example due to the reduced strength in the wet state. A lower limit results from the possibilities of the application method and is at least 0% of the starting surface weight, preferably at least 0.5% and particularly preferably at least 1%. Surfaces to which no order of the composition is made, of course, can also be provided.

For the drying of the cigarette paper after the application of the composition, any type of dryer can be used, for example hot air dryer, infrared dryer, tunnel dryer, heated drying cylinder or even a drying by microwaves.

The drying of the cigarette paper after the application of a water-based composition is preferably carried out by contact with one or more heated Trockenzylindem. Treating the paper with waterborne compositions often results in the formation of wrinkles in the paper that can be efficiently reduced by drying with drying cylinders. As an additional measure, one or more spreader rollers or smoothing devices can be provided which pull wrinkles from the paper during drying and are preferably arranged so that the paper passes over one or more spreader rollers or the smoothing devices prior to contact with the first drying cylinder. Alternatively, but less preferably, the spreader rollers or smoothing devices may also be arranged after one or more drying cylinders. Of course, in the case of compositions that are not water-based, these technologies can also be used, but the problem of wrinkling does not occur there or only to a considerably lesser extent.

Other parameters that must be set for the application of a composition in printing processes or other processes, such as temperatures, viscosities, velocities, or the design of the printing cylinder, can be easily found by those skilled in the art from their knowledge.

Many application methods also make it possible to vary the content of at least one Brandsalzes not only in the "longitudinal direction" of the paper, ie in the direction of the longitudinal axis of the cigarette to be produced, but also in the transverse direction, ie on the cigarette to be produced in the circumferential direction.

For the subject invention, it depends in the circumferential direction only on the average content of the at least one Brandsalzes, which is why preferably the content of the at least one Brandsalzes in the cigarette paper in the transverse direction, i. is substantially constant in the circumferential direction on a cigarette made from the paper according to the invention. This prevents the cigarette from smoldering unevenly around its circumference, and ash or tobacco falling out or the ash image being deteriorated.

Brief description of the figures

FIG. 1

shows a cigarette and arranged above it in a diagram an exemplary course of the content of the at least one Brandsalzes.

FIG. 2

shows an exemplary course of the content of the at least one Brandsalzes along the cigarette paper, as it results from the usual manufacturing process of machine-made cigarettes.

Detailed description of the invention

In the following, some examples will demonstrate the desired effect according to the invention.

On a cigarette paper with a basis weight of 30 g / m ² of wood pulp, a content of precipitated lime as a filler of 30% of the paper pulp and an air permeability of 50 cm min ^-1 kPa ^-1 , according to ISO 2965, trisodium citrate was applied as Brandsalz.

More specifically, an aqueous solution was prepared from the brine salt, as prepared for the prior art infusion of the paper. The content of Brandsalz in the solution resulted from the desired course of the content in the cigarette paper and the specifications of the application process.

The application of the burn salts was carried out by gravure printing with an engraving of the gravure cylinder corresponding to the geometry of the desired course.

From the cigarette paper, cigarettes having the following properties were manually made. diameter 7.8 mm Length of the cigarette 84 mm Length of the filter 24 mm filter cellulose acetate Length of mouthpiece tipping paper 32 mm Filling weight of the tobacco rod 750 mg tobacco blend American blend

First, long tubes were made from the cigarette paper and cut so that on the cigarette made from it the course of the Brandsalzes corresponds to the desired course. Thereafter, the tubes were filled with tobacco and a filter plug was connected by means of tipping paper with the tobacco-filled tube.

Each 60 cigarettes for each course of Brandsalzgehalts were smoked by machine according to ISO 4387 and collected the tar and nicotine generated each turn in a Cambridge filter pad . From the analysis of the Cambridge Filter Pad, tar and nicotine were determined for each pull.

The content of tar and nicotine in each train was calculated as the mean (M) in mg over all trains, the coefficient of variation (CoV) in% across all trains and the ratio V of the content between last and first train. The coefficient of variation is the standard deviation of the respective smoking value over all the traits of a cigarette divided by its mean and expressed as a percentage. The course of the Brandsalzgehalts according to the function f (x) are characterized by the parameters c ₀ , c _L , L ₁ and L ₂ and shown together with the results in Table 1. Table 1 course tar nicotine No. c ₀ c _L L ₁ L ₂ M CoV V M CoV V % % mm mm mg % mg % 1 1.4 1.4 0 52 1.25 16.1 1.62 0,075 11.6 1.41 2 0.7 0.0 0 52 1.33 13.0 1.47 0.082 7.6 1.25 3 1.4 0.0 0 52 1.30 12.5 1.44 0,080 6.4 1.20 4 2.0 0.0 0 52 1.29 13.5 1.47 0.078 6.8 1.20 5 2.7 0.0 0 52 1.31 16.0 1.56 0.078 8.9 1.25 6 3.5 0.0 0 52 1.35 19.9 1.70 0,080 12.5 1.35 7 2.7 2.5 0 52 1.52 9.4 1.32 0.086 6.6 1.21 8th 2.0 3.5 0 52 1.45 7.1 1.23 0.082 4.8 1.15 9 1.4 3.5 0 52 1.40 6.2 1.18 0,080 4.5 1.12 10 0.7 3.5 0 52 1.37 6.9 1.18 0.079 6.1 1.15 11 0.0 3.5 0 52 1.36 9.3 1.23 0,080 9.1 1.22 12 1.4 3.5 10 40 1.41 4.9 1.18 0.081 3.9 1.13 13 1.4 3.5 5 45 144 4.5 118 0.083 3.4 1.13

The course no. 1 corresponds to a constant Brandsalzgehalt of 1.4% and served as a comparison. On the basis of the ratio V, a clear increase in the tar content of 62% and in the nicotine content of 41% can be seen. The coefficients of variation of tar and nicotine are 16.1% and 11.6%.

The courses 2 to 6 show a sinking from the mouth end to the cigarette tip content of fire salt, while the courses 7 to 13 correspond to an increasing content of fire salt. In the courses 12 and 13 is still in addition to a length of 10 mm and 5 mm respectively at the mouth end and the cigarette holder, the content of Brandsalz constant and in between linearly increasing.

It can be seen from Table 1 that for the courses 2-5 and 7-13 both the coefficient of variation of the tar content and the ratio of the tar content between the last and first train is lower than in the comparison cigarette with the constant course from Example 1. When Nicotine content could be improved even for all gradients 2-13 in terms of the coefficient of variation of the nicotine content or in terms of the ratio in the nicotine content between last and first pull an improvement compared to the reference cigarette.
It can also be seen that in the courses 2-6 with decreasing Brandsalzgehalt along the tobacco rod only smaller improvements can be achieved than with the increasing courses 7-11. This applies to both tar and nicotine. For example, the lowest coefficient of variation of the tar content of gradients 2-6 is obtained at 12.5% on the course 3, ie a drop of 1.4% to 0% Brandsalzgehalt, while the same parameter for all courses 7-11 is already below this value, and for course 9, an increase from 1.4% to 3.5% Bratsalzgehalt, a minimum of 6.2% achieved.

The effect is utilized that at a constant content of about 1.5% to 3.0% trisodium citrate in the cigarette paper, a minimum occurs at tar and nicotine levels.

Both in the direction of the cigarette holder, x = L, sloping gradients 2-6, as well as rising in this direction gradients 7-13, thereby exploiting the effect that near the filter end; where the "strong" traits arise, a Brandsalzgehalt is present, which leads to lower tar and nicotine levels.

Compared to the other examples, however, shows that the courses 6 and 11 are less preferred, because in these courses, the contents of Brandsalzen Filterfilter with 3.5% at 6 and 0% at course 11 already clearly from that Brandsalzgehalt differ, with the minimum tar and nicotine values are reached. With these two Thus, the possibilities for stabilizing the train profile are not fully exploited.

In general, therefore, the fire salt content in the region of the filter end can be selected at least approximately so that it leads to a minimization of a specific smoke value, in particular nicotine or tar, and starting from this value in the direction of the Cigarette tip monotonically or approximately monotonically increases or decreases. The term "approximately chosen so" should also allow deviations from the ideal value of the Brandsalzkonzentration that less than 50%, preferably less than 30%, more preferably less than 15% of the ideal amount with the "per se same cigarette" is also a Cigarette made of the same base cigarette paper or of a similar base cigarette paper in which the grammage does not differ by more than 20% and the mean air permeability according to ISO 2965 by more than 15% from the same base cigarette paper. Particularly good results are shown in the two courses 12 and 13, in which, in addition to the linear increase from 1.4% to 3.5% Brandsalzgehalt, at the mouth end and the cigarette holder respectively areas with a constant Brandsalzgehalt of 1.4% and 3, 5% are provided on a length of 5 mm or 10 mm. Although the ratio of tar and nicotine content between the last and the first move hardly achieves any improvement compared to Examples 2-11, the coefficient of variation of tar and nicotine can be further reduced and reaches values of 4.9% and 4.5% for Tar and 3.9% and 3.4% for nicotine.

The most preferred embodiment of Examples 12 and 13 is in FIG. 1 shown. An exemplary cigarette 100 consists of a filter 101 encased in a tipping paper 102 which partially overlaps the tobacco rod 103, which in turn is enveloped by a cigarette paper 104. On the cigarette 100, the tipping paper 102 is then in the overlap zone over the cigarette paper 104. The dashed line 105 indicates the boundary between the filter and the tobacco rod so that the overlap zone from the dashed line 105 to the position x = 0 along the cigarette axis runs. This in FIG. 1 Diagram 110 arranged above the cigarette 100 shows an exemplary profile of the content of the at least one fire salt. The x-axis 111 shows the position x = 0 at the beginning of the visible tobacco rod and the position x = L at the end of the cigarette to be ignited. On the y-axis 112 is the content of the at least one Brands salt applied. First, the content of the at least one Brandsalzes in the range of x = 0 to x = L ₁ at the level c ₀ constant, reference numeral 113, then it increases in the range of x = L ₁ to x = L ₂ linearly from the level c ₀ to to the level c _L on, reference numeral 114, and then remains up to the position x = L back to the level c _L , reference numeral 115. Of course, this is an idealized course of the deviations in reality, for example, by the usual production tolerances and Inhomogeneities of the paper are possible.

In the manufacture of cigarettes, an endless tobacco rod is formed which is cut into pieces having the length of the tobacco rod on the cigarette. Between each pair of such pieces, a double-length filter plug is inserted and glued to a doubly wide mouthpiece covering paper to form a double cigarette connected to the filter end. In a final cut, the double cigarette is divided into two cigarettes and turned over one of the two cigarettes, so that all running out of the cigarette machine cigarettes are the same orientation. This results in the need to choose the course of the content of at least one Brandsalzes along the cigarette paper web accordingly. Such an exemplary course is in FIG. 2 shown.

The main direction of the cigarette paper, typically the machine direction, is indicated by the arrow 201. In the direction 202, the content of the at least one Brandsalzes is plotted and its course in the direction 201 is represented by the line 203. On the cigarette machine, a piece of tobacco rod is made by cutting at each of the positions indicated by lines 204 and 205. The demarcated by the dashed lines 206 area 207 comes to rest on the double cigarette under the tipping paper and is thus not visible in normal use. In this area 207, the course of the content of at least one Brandsalzes plays no role, because this area is not usually smoked. The x-axes 208 indicate the course of the x-coordinate from the position x = 0 to the position x = L for each cigarette made from the tobacco rod. By producing a double cigarette with the subsequent cut along the lines 204 and 205 and the turning of the cigarette, it is necessary that along the direction 201 each of an ascending and a falling course follow each other periodically, if on the manufactured cigarettes the course of Salary of the at least one Brandsalzes in the visible tobacco rod should always be nominally equal.

To synchronize the cut of the tobacco rod with the curve 203 of the content of the at least one Brandsalzes mark themselves at the indicated by the lines 205 positions, so in the areas 207 offer because the areas 207 are overlapped on the cigarette through the tipping paper and thus the Markings are not visible.

Of course, this is only an exemplary course, and it is easy for a person skilled in the art, for any desired course of the at least one Brandsalzes on the cigarette to determine the corresponding course on the cigarette paper web as a function of the manufacturing process of the cigarette.

The application of brine salts according to the invention also leads to changes in the total tar and nicotine content even compared to the comparative cigarette with the constant course from Example 1. However, these changes can be compensated simply by adapting the filter ventilation or the filter without impairing the effect according to the invention ,

Based on these examples, the skilled person will be able to find a course of the invention content of at least one Brandsalzes with little experimental effort for a large class of Brandsalzen, so that the invention can be easily transferred to a variety of Brandsalze. Likewise, he will be able to find a desired course of the content of at least one Brandsalzes for different cigarette papers and cigarette designs.

Claims (15)

1. Cigarette paper containing at least one burn additive, wherein
   the concentration c(x) of the at least one burn additive varies along a direction x of the cigarette paper, characterized in that
   for the position-dependent concentration c(x) over an interval of length L the following holds for x over the interval [o,L]: $$f\left(x\right)-\mathrm{\Delta }\mathit{c}\le c\left(x\right)\le f\left(x\right)+\mathrm{\Delta }\mathit{c}$$

   

   wherein:

   • 3 cm ≤ L ≤11 cm,

   • f(x) is monotonic over the interval [o,L], but is not a constant function over the entire interval,

   • Δc ≤ 1% by weight and Δc ≥ 0% by weight, respectively with respect to the mass of the cigarette paper, and

   • |f(L) - f(0)| ≥ 2Δc.
2. Cigarette paper according to claim 1, in which Δc ≤ 0.7% by weight, preferably ≤ 0.5% by weight, particularly preferably ≤ 0.3% by weight and especially preferably ≤ 0.15% by weight, and/or.
   in which |f(L) - f(0)| ≥ 0.5% by weight, preferably ≥1.0% by weight and particularly preferably ≥ 2.0% by weight.
3. Cigarette paper according to one of the preceding claims, in which the function f(x) is defined as follows: $$f\left(x\right)=\{\begin{array}{cc}{c}_0& 0\le x\le L_1\\ c_0+\left(c_L-c_0\right)\frac{x-L_1}{L_2-L_1}& L_1<x<L_2\\ c_L& L_2\le x\le L\end{array}$$

   

   in which c₀ or c_L is preferably greater than or equal to 0% by weight, in particular preferably ≥ 0.2% by weight and particularly ≥0.5% by weight and/or preferably ≤ 15.0% by weight, particularly preferably ≤ 10.0% by weight and in particular ≤7.0% by weight, wherein in each case c₀ and c_L, are different from each other.
4. Cigarette paper according to claim 3, in which L₁ ≤ 2L/3, preferably ≤ L/2 and particularly preferably ≤ L/3, and/or L₁ ≥ 0, preferably ≥ L/6, and/or
   L₂ ≥ L/3, preferably ≥ L/2 and particularly preferably ≥ 2L/3 and/or L₂ ≤ L, preferably ≤ 5L/6, wherein L₁ ≤ L₂ always holds, and/or
   L₂ - L₁ ≥ L/6, preferably ≥ L/3 and particularly preferably ≥ L/2 and/or L₂ - L₁ ≤ 9L/10, preferably ≤ 4L/5 and particularly preferably ≤ 2L/3.
5. Cigarette paper according to one of the preceding claims, with at least one mark, the position of which on the cigarette paper being in a pre-determined spatial relationship to the function c(x), wherein the mark is preferably detectable by an optical sensor, wherein the cigarette paper is preferably intended for a filter cigarette and in which the mark is at a position that is located under the tipping paper on a filter cigarette that is to be manufactured therefrom and/or where the mark is applied to the side that is facing away from the tobacco on a finished cigarette.
6. Cigarette paper according to one of the preceding claims, in which the described profile c(x) varies periodically, alternating in normal and reverse directions.
7. Cigarette paper according to one of the preceding claims, in which the at least one burn additive contains one or a mixture of more of the following burn additives: tri-sodium citrate, tri-potassium citrate, further citrates, malates, tartrates, acetates, nitrates, succinates, fumarates, gluconates, glycolates, lactates, oxylates, salicylates, α-hydroxy caprylates, hydrogen carbonates, carbonates and phosphates, and/or
   in which the cigarette paper at least partially consists of pulp fibers or a mixture of pulp fibers, wherein the pulp fibers have preferably been sourced from wood, flax, hemp or esparto grass,
   wherein the cigarette paper preferably has a basis weight from 10 g/m² to 60 g/m², in particular from 20 g/m² to 35 g/m².
8. Cigarette paper according to one of the preceding claims, further containing an inorganic mineral filler, in particular chalk, other oxides, in particular magnesium oxide and aluminum hydroxide, carbonates or mixtures thereof, wherein the filler preferably has a weight ratio of 10% to 45% of the cigarette paper, and/or
   in which the air permeability is between 0 cm min^-1 kPa^-1 and 350 cm min^-1 kPa^-1, preferably between 20 cm min^-1 kPa^-1 and 200 cm min^-1 kPa^-1 and particularly preferably between 30 cm min^-1 kPa^-1 and 120 cm min^-1 kPa^-1.
9. Process for producing a cigarette paper with the following steps:

   - providing a base cigarette paper

   - introducing at least one burn additive into the base cigarette paper in a position-dependent concentration c(x) that varies along a direction x of the cigarette paper,

   characterized in that the position-dependent concentration c(x) over an interval of length L for x over the interval [0,L]: $$f\left(x\right)-\mathrm{\Delta }\mathit{c}\le c\left(x\right)\le f\left(x\right)+\mathrm{\Delta }\mathit{c}$$

   

   wherein:

   • 3 cm ≤ L ≤11 cm,

   • f(x) is monotonic over the interval [0,L], but not a constant function over the entire interval, and

   • Δc ≤ 1% by weight and Δc ≥ 0% by weight, respectively with respect to the mass of the cigarette paper, and

   • |f(L) - f(0)| ≥ 2Δc.
10. Process according to claim 9, in which Δc ≤ 0.7% by weight, preferably ≤ 0.5% by weight, particularly preferably ≤ 0.3% by weight and particularly preferably ≤0.15% by weight.
11. Process according to claim 9 or 10, in which the at least one burn additive is applied to the base cigarette paper in the form of a liquid composition, in particular a solution, suspension or another form of mixture in a solvent, in particular by a printing process or by spraying, wherein
    the printing process is preferably roto-gravure printing or flexographic printing, wherein the flow time of the composition is 10 s to 40 s, preferably 12 s to 35 s, measured in accordance with ONORM EN ISO 2431:2011 with a cup with an opening of 4 mm at the temperature at which the composition is used in the application process,
    wherein in case of roto-gravure printing, a roto-gravure printing cylinder with a recesses is preferably provided from which the composition to be printed is transferred to the base paper, wherein the volume of the recesses and/or the density of the recesses on the roto-gravure printing cylinder is/are selected such that the desired position-dependent concentration c(x) of the burn additive is obtained.
12. Process according to one of claims 9 to 11, in which at least a part of the at least one burn additive is introduced by impregnation of the paper

    - in the size or film-press of a paper machine, or

    - in equipment downstream of the paper machine

    with a solution, in particular a water-based solution of the burn additive, and/or in which the at least one burn additive is initially introduced to the paper with an approximately uniform concentration and then washed out in a position-dependent manner, in order to obtain the desired position-dependent burn additive concentration.
13. Process according to one of claims 11 or 12, in which the content of the at least one burn additive or burn additive mixture in the composition is at least 0.1% by weight, preferably at least 1% by weight and particularly preferably at least 2% by weight and/or at most 15% by weight, preferably at most 10% by weight and particularly preferably at most 7% by weight with respect to the mass of the composition, and/or
    in which the composition contains substances for adjusting the viscosity, in particular polymers or a mixture of polymers,
    wherein the polymers are preferably a cellulose derivative, in particular carboxy methyl cellulose, a polysaccharide, in particular starch or starch derivatives, an alginate, a dextrin, guar or gum Arabic or combinations thereof.
14. Process according to claims 9 to 13, in which the applied amount of the composition per unit area corresponds to at most 100%, preferably at most 80% and particularly preferably at most 60% of the corresponding initial basis weight before application of the composition.
15. Process according to one of claims 9 to 14, further comprising the step of drying the cigarette paper after application of the composition, in particular using a hot air dryer, an infra-red dryer, a tunnel dryer, by heated drying cylinders or the use of micro-waves, wherein
    the composition is preferably water-based and drying is carried out by contact with one or more drying cylinders that can be heated,
    wherein preferably, in addition, one or more spreader rollers or smoothing devices are provided that are suitable for pulling wrinldes out of the paper during drying and that are preferably arranged such that the paper runs over one or more spreader roller(s) or smoothing device(s) before the drying cylinder.

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