EP3048906A2

EP3048906A2 - Coating method

Info

Publication number: EP3048906A2
Application number: EP14824344.7A
Authority: EP
Inventors: Guenter Griesmayr; Barbara PUEHRINGER; Bernhard KNAUSEDER; Eike SCHOPPER
Original assignee: Tannpapier GmbH
Current assignee: Tannpapier GmbH
Priority date: 2013-09-27
Filing date: 2014-09-25
Publication date: 2016-08-03
Anticipated expiration: 2034-09-25
Also published as: AT514862A1; HUE036383T2; JP2016536977A; WO2015042627A3; MX2016003806A; EA031273B9; AU2014328446A1; KR102080372B1; BR112016006487B1; ES2657425T3; HK1218054A1; US20160262446A1; AU2014328446B2; CL2016000704A1; CN105555154A; NO3048906T3; PL3048906T3; TW201519801A; EA201690578A1; RS56651B1

Abstract

The invention relates to a coating method for sheathing material formed from paper or card for smoking materials or parts of smoking materials in order to reduce the tendency of said sheathing material to absorb and diffuse aqueous or oily substances, the sheathing material being provided on the same side with two coatings, which are applied one on top of the other and are each applied in liquid form in two successive coating steps, the liquid coating mixture in both coating steps consisting of a coating substance and a liquid volatile matrix. In the first coating step, at least one layer of a first coating substance is applied, which reduces the ability of the paper or card to absorb the liquid volatile matrix of the second coating substance; in the second coating step, at least one layer of a second coating substance is applied, which is repellent or impermeable to one or more of the following substances: oils, fats, waxes, alcohols, and water. The liquid volatile matrix used for the first coating substance is different from that used for the second coating substance.

Description

coating process

The invention relates to a coating method for wrapping material made of paper or cardboard for smoking products or parts of tobacco products, the coating method has the purpose of this coating material tends to absorb aqueous or oily substances, as well as the diffusion or migration of such substances through the paper or to reduce the carton. Furthermore, the invention relates to the corresponding coated cladding material.

The invention will be further described primarily with reference to tipping paper for cigarettes as an exemplary casing material according to the invention. The reason for this is that the tipping paper is probably the most important application for the invention and that the description becomes easier to understand by focusing on only a single application. Only in the last part of the description will be briefly discussed further applications.

Essential parts of a conventional filter cigarette are the tobacco rod, the filter and sheathing material in the form of the cigarette paper enveloping the tobacco rod, the filter wrap paper directly enveloping the filter and the tipping paper.

The tipping paper, often referred to as "tipping paper" or "tipping" for short, is that part of the filter cigarette which is touched by the lips of the person smoking the cigarette when the filter cigarette is smoked, enveloping the filter part and usually extending longitudinally of the filter cigarette It is adhesively bonded to the filter wrap paper and the cigarette paper, and by making this bond, the filter part and the tobacco rod part are mechanically connected in the cigarette machine but may also be a film or a composite material of several layers of different materials.

Usually, the tipping paper has an imprint. For example, this print can be reminiscent of cork.

In the Applicant's Austrian Patent Application A 1013/2012 (now published as AT 513413 Al), not yet published on the priority date of the present application, the requirement is stated that an oil-tight barrier should be present between the outer layer of the tipping base paper and the filter wrapper paper, in particular if the mouthpiece covering paper is provided with a substance having a sensory effect (eg substance which causes a sensation of cold when touched with the lips), since this prevents the generally undesired diffusion of this substance into the filter material. According to A 1013/2012, it is proposed to apply an oil-tight film between tipping paper and filter wrap paper.

EP 2551407 Bl proposes a filter wrapper which, compared to other filter wrappers, significantly better brakes oil diffusion, while still itself being a light and very porous, ie well air-permeable, paper, as is important for filter wrap papers. The filter wrapper paper is particularly advantageous when using filters containing liquid flavorant which is intended to enrich the smoke stream but not to diffuse so much through the filter wrapper paper and into the mouthpiece overlay paper running around the finished cigarette outside thereof visible marks appear on the visible surface of the tipping paper. According to EP 2551407 Bl, a special base paper - defined by the freeness of the long fiber pulp and the filler fraction - is proposed for the filter wrap paper, which is impregnated with an aqueous composition, in particular an aqueous solution or suspension. In a further development, it is subsequently nierung on the filter wrapper additionally applied a layer in a likewise aqueous solution.

In DE 2743986 AI Mundstückbelagspapier is proposed, which is colored through and provided with an embossing reminiscent of the natural surface of cork. As a protective coating for embossing and to achieve a gloss effect, the side of the tipping paper intended as the visible side is additionally provided with a lacquer coating. Lacquers for this purpose are exemplified by shellac, ethyl cellulose and polyethylene wax styrene acrylate.

In WO 2009027331 A2, a mouthpiece covering paper is proposed, which is coated with a composite of nitrocellulose lacquer and a cold sensation substance.

EP 10446115 B1 proposes a cigarette paper (ie a paper intended for wrapping the tobacco rod), which is provided with a water-repellent impregnation of cellulose derivative. In order to achieve a desired good air permeability of the cigarette paper despite the impregnation, it is proposed to apply the impregnation in several successive coating operations.

US 2009/0065012 A1 and US 2004/0099280 describe multiple coatings for cigarette paper (ie a paper intended to wrap the tobacco rod) which are applied in several bands to form self-extinguishing cigarettes.

The object underlying the invention is to provide sheathing material in particular mouthpiece covering paper in that processing state, from which only one or more customized optically and / or otherwise sensory perceptible imprints are missing until processing in the cigarette machine. The special requirements for the tipping paper to be provided in said processing state are: The tipping paper should actually be a paper, not a foil. (This is required mainly for haptic reasons, for reasons of further printability and for reasons of processability in the cigarette machine.)

The tipping paper coated according to the invention is said to have a significantly lower tendency to form stains due to ingestion of aqueous, oily, greasy, waxy or alcoholic substances, and diffusion of these substances through the tipping material, irrespective of other customer-specific imprints compared to other papers used as tipping paper.

- The desired "stain prevention" of the tipping pad should be reliable and independent of the properties of the base paper used.

To solve the problem, it is proposed to provide the base paper originating from the papermaking process in two successive coating processes with coatings applied in liquid form, a weakly hydrophobic coating substance being applied as a liquid, volatile matrix during the first coating operation with a preferably organic solvent and wherein in the second process with preferably water as a liquid, volatile matrix, a more hydrophobic and oil-repellent coating material is applied. "Liquid volatile matrix" is understood to mean all types of solvents (inorganic and organic) and dispersion media of dispersions, emulsions or suspensions.

The purpose of the first coating process is essentially to protect the paper from damage caused by the water which is forcibly applied during the second coating process. Only with the second coating process is that coating applied, which has the decisive desired effect of "stain avoidance", in particular the lowest possible tendency to build up take and migration or diffusion of aqueous, oily, waxy and alcohol-based substances causes. According to the present document, a coating process is defined as the application of a coating material, and a coating process can also consist of a time-separated application of several overlapping layers of the coating material.

The desired effect of "stain avoidance" requires a coating which is oil repellent or even oil-tight. The applicant at the time of the invention known oil-repellent or oil-tight coating materials which can be applied in liquid form, are dissolved in water or aqueous solutions, or are present as a dispersion with water as a dispersion medium. However, water as a volatile liquid matrix for paper coatings can only be used to a very limited extent because untreated paper absorbs water quickly and can change to permanent uselessness, namely becoming soft and rough, enlarging its enveloping surface, causing waves and no longer being processed can.

By first applying a coating which is not based on water as a volatile liquid matrix prior to the application of the second, ultimately essential oil repellent coating based on water as a volatile liquid matrix, and which reduces the water absorbency of the paper, the second coating can be used a much larger amount than you could otherwise and thus achieve a much better desired effect ("stain prevention"), than you could otherwise. Spots are local changes in appearance by water, alcohols, solvents, waxes, fats or oils (for example, fatty oils, mineral oils, silicone oils, essential oils). Of course, the invention is also applicable to such a second coating whose volatile liquid matrix, while not based on water, would also undesirably alter the properties of the paper or paperboard. The first coating is therefore generally formulated to the absorption capacity of the

Paper or cardboard against the volatile liquid matrix of the second coating.

The coating according to the invention is particularly advantageous in the case of paper grades with a low grammage (below 80 g / m ² , preferably below 40 g / m ² ), since the negative influence on the paper properties increases with increasing absolute moisture in the paper.

The invention will now be further explained with reference to an embodiment.

Fig. 1: shows the schematic representation of an exemplary coating method according to the invention.

Figure 2: Shows as a result of an ink floating test a tipping base paper coated according to the invention and two comparative papers.

FIG. 1 shows an exemplary online process for producing a paper coated according to the invention. "Online" in this context means that the paper is present as a paper web 4, which is pulled through the coating system and coated continuously. The paper web is usually unwound from a paper roll (mother roll or reel) and wound up again after the coating to a paper roll, or further processed directly, for example, cut into strips. The coating according to the invention is carried out in four steps:

In the first step, the first, lower coating is applied by a coating device 1.1.

In the second step, the first coating is dried.

In the third step, the second coating is applied over the first coating in the coating device 1.2.

In the fourth step, the second coating is dried. The first and second steps and / or the third and fourth

Step can be done multiple times. Say the first and / or second coating process can be carried out by applying a plurality of layers applied one behind the other.

As modifications, it would be conceivable to apply the lower or both coatings according to the invention on both sides or to apply one of the two coatings in succession in succession, wherein each application of a layer is followed by a drying process. It is also possible to see a printing device according to the coating devices before to apply a printing with optical, haptic, sensory or other function on the dried coating, or the other paper side. It would also be conceivable to carry out the application of the first coating and the second coating on two separate systems, for example for space or process engineering reasons. In this case, the paper web 4 is already wound after drying the first coating to form a paper roll. This paper roll is then transported to a second plant where the paper web (4) is unwound and provided with the second coating.

As shown in Fig. 1, the drying can be accelerated by the action of hot air or infrared radiation. As a particularly valuable drying method for the coating according to the invention, a combination of hot air and infrared drying has been found. The coating is, for example, first irradiated with infrared radiation, preferably from the uncoated back side of the paper. So the coating begins first in depth, so to dry on paper. This allows the evaporated solvent (or, more generally, the volatile liquid matrix) to escape through the upper, still liquid layers of the coating that are in the air. Once sufficient solvent has evaporated from the deeper layers, the evaporation of the near-surface can be Solvent by additionally accelerating the drying with

Infrared or hot air from the coated side of the paper forth. This drying process is particularly valuable for the second coating since the volatile liquid matrix of this coating can not escape through the underlying already dried first coating.

The number and arrangement of hot air and infrared sources (2.1, 2.2, 3.1, 3.2, 3.3), as well as the intensity and duration of exposure to them, depends on the paper used and the type and quantity of paint used, and may best be determined by experiment be determined. For example, one or more infrared sources (3.1, 3.2, 3.3) may be mentioned from above (coating side), one-sided from below or on both sides; one or more hot air sources (2.1, 2.2) on one side from above, one-sided from below or on both sides; and combinations of said arrangements of infrared sources (3.1, 3.2, 3.3) and hot air sources (2.1, 2.2). The action of the infrared sources (3.1, 3.2, 3.3) and hot air sources (2.1, 2.2) can be carried out simultaneously or staggered.

Example:

Starting material is an exemplary pulp fiber based base paper, as is common for tipping paper. It has a grammage (basis weight) of about 20-80 g / m ² , in the present example 35 g / m ² .

If the base paper were to be provided directly with the second coating (eg water-based styrene-acrylate lacquer) without the first coating operation, then the readily absorbent base paper would absorb approximately the entire amount of the liquid component of the lacquer. At a solids application of 5 g / m ² and a typical paint composition having a solids content to liquid fraction of 30:70, the mass of the applied liquid is 11.7 g / m ² . Thus, 11.7 g of water are added per 35 g of paste. applied, which corresponds to an increase in the absolute paper moisture, defined as [(wet mass - dry mass) / wet mass], of about 25 wt .-%. By comparison, with the same coating at a grammage of 80 g / m ^2, the absolute paper moisture would only increase by 12.7% by weight. The Applicant has found that with an increase in the regular paper moisture (4 - 7 wt .-%) to an absolute paper moisture of about 14 wt .-%, the paper properties are so adversely affected that the tipping material can not be processed properly. This illustrates the high importance of the coating according to the invention especially for absorbent paper grades with low grammage, since the absorption capacity of the paper for the liquid content of the second coating is reduced by the first coating.

Shellac is used as a coating material for the first coating process. Shellac is mixed with ethanol as a solvent until a flow time of between 18 and 22 seconds results when measuring the viscosity of the mixture with the flow cup test with a cup diameter of 4 mm (ISO cup 4 mm according to EN ISO 2431 version 1993-02-15). Per m ^{2 of} paper, 1 to 6 grams, preferably 3 to 3.5 grams of dry application amount of this mixture are applied evenly on the base paper by gravure printing. The dry application rate can be measured as the weight increase of the paper after drying of the coating and thus represents the mass of the applied, non-volatile coating material.

After the first coating operation, the paper is dried in air at a temperature of 70 ° C to 120 ° C for at least 1-4 seconds.

It is possible to test the success of the first coating, namely "falling below a maximum permissible water absorption capacity of the paper from the side of the coated surface" by means of the standardized so-called Cobb test (ISO 535). When water is used as the test fluid and Cobb 300 (300 seconds exposed to the sample amount of water) or a longer Cobb test is successful, said water absorbency is sufficiently low for this stage of processing. (According to the standard, the test is feasible if more than 80% of the samples do not penetrate within the test period). Cobb30 O values of less than 25 g / m ^{2 were} measured on the samples.

The second coating is applied to the same side of the paper as the first coating, covering the first coating. For the second coating process, styrene-acrylate paint is used, in which water is the liquid volatile matrix. The proportion of water is so high that, when measuring the viscosity with the outlet cup test with a cup diameter of 4 mm (ISO cup 4 mm according to EN ISO 2431 version 1993-02-15), a flow time of between 11 and 23 seconds results. For each m ^{2 of} paper, 1 to 6 grams of dry coating of the coating material, which is present in the liquid-volatile matrix of the liquid paint, is evenly applied by gravure printing.

After the second coating operation, the paper is dried in air at a temperature of 70 ° C to 120 ° C for at least 1-4 seconds.

Even after the second coating, success can be tested using the Cobb test (ISO 535). Again, Cobb300 can be used, in which case the test must be possible with both water and oil as the test fluid. The test with oil is based on the standard SCAN-P 37:77, which describes the Cobb-Unger method. The CobbU value indicates the mass (in grams) of oil that is absorbed in a standardized period of time (6, 10 or 30 seconds) on one square meter of paper. The modification of the test consists in determining the CobbU300 (test duration 300 sec). Cobb300 was chosen because the test duration is approximately the same as the duration of smoking a cigarette. Preferably a Cobb300 value or CobbU300 value of less than 1 g / m ² results in a successful coating at two test liquids less than 0.5 g / m ² Gewichtszunah- According to the paper during the test period through the coated surface recorded test liquid. The standard CobbU30 value (test duration 30 seconds with oil) is therefore also less than 1 g / m ² or less than 0.5 g / m ² .

As a test method for the success of the second coating - and thus also included for the success of the first coating - is very well suited for the assessment of the tightness against oil and grease diffusion in paper usual KIT test. On the 12-part result scale, if the two coatings are properly applied, at least the value 11 is achieved; but it is also a value of 12 achievable and of course preferred. The value 12 means highest resistance to diffusion by oily or similar substances.

(The official name of the KIT test is "Grease resistance test for paper and paperboard T 559 cm-12".) The relevant standardization body is TAPPI (Technical Association of the Pulp and Paper Industry) 12 well-defined oily liquids are added dropwise and it is observed for each drop, whether the respective liquid penetrates to the second surface within a standardized test period.The oily liquids are numbered and have more diffusibility with increasing number.The result of the test is the highest of those Numbers to which the associated liquid does not penetrate the second paper surface during the test period.)

Modifications and generalizations for the coating according to the invention of the paper according to the example are:

For the first coating process are in addition to said shellac as coating materials and ethylcellulose paint (preferably applied in several layers), alkyd resin or nitrocellulose lacquer, wherein combinations of said coatings are particularly advantageous applicable, such as a mixture of shellac and nitrocellulose lacquer or ethyl - cellulosic lacquer or a mixture of alkyd resin lacquer and nitrocellulose luloselack or ethylcellulose lacquer. The mentioned paints or

Lacquer combinations can also be used advantageously in combination with paraffin wax, for example nitrocellulose lacquer, alkyd resin lacquer or ethylcellulose lacquer in combination with paraffin wax. In general, paints and coating materials with similar physical properties to the paints mentioned above, especially in terms of tightness and hydrophobicity can be used. As an organic solvent, ethyl acetate, for example, may well be used instead of ethanol.

The viscosity of the still liquid coating mixture for the first coating process should be such that the flow-through cup test results in a flow time of between 13 and 35 seconds (preferably 18-22 seconds). As the viscosity increases, the concentration of the coating material is higher and more of it is applied per printing process, but it also becomes more difficult to get the coating tightly sealed.

In the first coating operation, a dry application of the coating material of 1 to 6 g / m ² should be applied to the coating mixture, preferably at least 3 g / m ² .

In addition to the abovementioned styrene-acrylate paints, lacquers and coating materials with similar physical properties, in particular with regard to impermeability, hydrophobicity and wettability by oily substances, are generally also suitable for the second coating process.

The viscosity of the still liquid coating mixture for the second coating operation should be such that the outflow cup test results in a flow time of between 11 and 23 seconds, preferably 11 and 12 seconds.

By using a relatively high-viscosity coating mixture in the first coating process, the risk is reduced that the paper will be damaged by excessive amounts of liquid. By using a less viscous coating mixture in the second coating operation, a smoother, more closed surface is achieved. Gravure printing as a method of application is advantageous because it is customary for the printing of tipping paper and for many technical reasons well suited. In the context of the inventive idea, however, it does not matter in principle with which method the liquid coating mixtures are applied, as long as the given rules for quantity per area, uniformity and consistency of the coating mixtures are adhered to. It is therefore also possible to use the flexographic printing process or other application processes.

The coating materials of both coatings are preferably transparent and colorless, but may also contain a colorant. Furthermore, it is possible to add additives and further components such as waxes and resins, for example paraffin wax, to the coating mixtures.

As already mentioned for the first coating in the case of ethylcellulose lacquer, the first coating can be multilayered even when using other lacquers, the same applies to the second coating.

The coating according to the invention is also advantageous if-unlike the example mentioned-papers are used which are already referred to as "wet-strength", because they are better wet-strength by the type of additives contained in the paper (wet strength or wet strength sizing) are as usual papers. The ability to absorb and diffuse aqueous or oily substances is further reduced in this case from a lower baseline. Depending on the properties of the starting material used and the objective of the "stain-avoidance capability", one can make do with less thick layer application according to the invention (more or less amount of liquid coating mixture or less or more volatile liquid matrix).

For fast debugging, whether for a paper grade the appropriate parameters were selected in the coatings and whether the process was carried out correctly, the so-called Ink-floating method very good. In this case, the coated paper is placed with the coated side down on the liquid level of an ink bath (with standardized ink) and it is observed whether and in which time ink penetrates to the top of the paper and discolored. In the case of sufficiently good coatings of tipping paper, after the first coating operation in the ink-floating method, a time of at least 15 seconds is measured before ink penetrates to the top of the paper. After the second coating process, this measured time is more than 300 seconds.

In Fig. 2, the result of the ink floating test is shown after 300 seconds. For the experiment, a typical tipping paper was used. In the ink bath there are three pieces of paper, on the left the mouthpiece covering paper without a coating, in the middle with a first coating formed by shellac and on the right the mouthpiece covering paper according to the invention with a first coating by shellac and a second coating applied with styrene-acrylate lacquer above. The uncoated paper can be recognized as a black area bounded by a white frame, since it is already completely saturated with the ink. The mottled surface of the single-coated paper shows that the ink has already penetrated the paper at the black spots. The tipping paper provided with two different coatings according to the invention does not show any signs of discoloration and can be recognized as a white rectangle.

This test confirms that the water absorption capacity is greatly reduced by the coating according to the invention and indeed so strong that discoloration of the paper is excluded for at least 5 minutes. Thus, the intended use of the mouthpiece covering paper ensures that aqueous substances can not penetrate it. Liquid substances that are contained inside the cigarette or released during smoking penetrate it not and do not appear as visible stains on the outside of the tipping paper.

Of course, it is also prevented that liquid substances that act on the tipping paper from the outside penetrate it and reach deeper layers of the cigarette.

From this aspect, another very advantageous application of the coating according to the invention has been discovered. Since the cigarette usually comes into contact with the lips of the smoker during smoking at its ends facing away from the tobacco rod, it is exposed to moisture in this area, which acts differently depending on the smoking habit on the cigarette. This may cause the paper to soften the cigarette and adhere to the smoker's lips.

It has been found that the coating according to the invention is also outstandingly suitable for the solution of this problem. For this purpose, the coating according to the invention is applied to the outside of the area of the smoking article which comes into contact with the lips of the smoker. In modern filter cigarettes, this is approximately the third of the mouthpiece covering paper facing away from the tobacco part. Appropriately, the tipping paper can also be coated before the composition of the cigarette.

When using a correspondingly pretreated tipping paper on a filter cigarette has been shown that this is not softened even after prolonged contact with saliva. In addition, it was also possible to prevent the lips from sticking to the paper when releasing the cigarette, which is perceived as unpleasant by many smokers. Coatings intended to prevent such adhesion are also referred to as lip-release coatings. It has been found that the lip-release effect of the coating according to the invention is even more pronounced and longer lasting than in the case of coatings The prior art, such as a coating with nitrocellulose lacquer.

Advantages and advantageous variants of tipping paper produced according to the invention are briefly explained:

If paper was coated on only one side with a coating according to the invention, the second paper side is still good water absorption. This is highly desirable in the processing of tipping paper in the cigarette machine, where the speed of processing depends substantially on how quickly an adhesion of tipping paper wrapped around the filter part to the overlap location of the tipping paper has reached a certain minimum strength by itself. The increase in strength increases with the ability of the paper to absorb moisture from the glue used for said bonding. If only one paper side is coated according to the invention, at least one of the two paper surfaces to be joined together is still receptive to liquids or moisture during bonding. This achieves an acceptably rapid increase in the strength of the bond. (Tipping papers which are formed from a continuous non-absorbent film or consist of consistently high wet strength sized paper are problematic in this regard.)

If very good barrier action is to be achieved by the tipping paper in both directions (out of the filter and into the filter), it makes sense to coat it on both sides according to the invention. By applying the coating as printing, it is quite possible and advantageous to leave individual surface areas unprinted on one side of the paper, in particular precisely those surface areas which serve as bonding surfaces of the tipping paper during processing of the paper in the cigarette machine. This is especially valuable for the overlap area - and therefore bonding area - of the tipping paper on the cigarette itself. However, it is also useful for the bonding surface area of the tipping paper with the filter paper and the cigarette paper.

The advantages of a coating according to the invention applied to the outside of the tipping paper are: a) The surface is much better suited for further printing with optical or haptic lacquers than an untreated paper surface since it is much smoother, denser and more error-free. It is therefore possible to print finer and more varied structures and generally requires less printing material. b) The surface has a so-called lip-release effect, that is, it does not tend to stick to the lips even after prolonged contact with wet lips - as is the smoking habits in some countries. It was also surprisingly found that the lip-release effect was even improved with the method according to the invention over known coating methods.

c) The coated surface prevents sensory-active substances, such as typically flavorings often applied locally on the outside of the tipping paper, from spreading in the tipping paper, mixing with other materials also applied to the tipping paper, or even partially into the filter and further enter the smoke stream. It thus makes it possible to use a wider range of sensory substances, to apply a wider range of combinations of these substances to a cigarette and also to provide a greater amount of these substances on the outside of the tipping paper than would otherwise be possible.

When the coating according to the invention is applied to the inside of the tipping paper, its main benefit is that it prevents substances from the inside of the coated area from reaching the outside of the tipping paper diffuse there and cause visible stains and / or an undesirable odor or taste sensation. Particularly important is this type of barrier, if in the filter part or in the tobacco rod of the cigarette in addition to the present without any flavor present by the tobacco, separate flavorings are housed, which are or include oily substances. Particularly significant in number here are the originally from Indonesia so-called Kretekzigaretten in which the tobacco clove oil, as a liquid or as shredded cloves and usually various other additives such as glycerin, molasses, palm sugar, cane sugar or other flavors are added.

A recent major trend is the use of so-called flavor capsules, mainly for attachment in the filter of cigarettes. A flavor capsule is a capsule whose outer shell, for example, by the exertion of pressure, is destructible. As a result, the flavorings contained in the capsule in liquid form and their carrier substances are released. The coating according to the invention is also ideally suited here to prevent the passage of these substances to the outside of the cigarette.

It is also possible, for example, to print microcapsules in the form of microscopically small aroma capsules directly on the outside of the mouthpiece covering paper. The coating according to the invention is suitable for preventing the passage of the substances contained therein into the interior of the cigarette.

For example, vanilla or menthol are used as flavorings for aroma capsules, microcapsules or direct printing. For example, polyethylene glycol (PEG) is used as carriers for flavorings.

If the coating according to the invention is applied only to the inside of the tipping paper, it can be perceived as a haptic advantage that the tipping paper approaches the cigarette feels velvety and less film-like than it would feel if it were also coated there according to the invention.

Not only in Kretekzigaretten often occurs the problem of unwanted staining not only on the mouthpiece covering paper of the cigarettes themselves, but also on the existing paper or cardboard packaging in which the cigarettes are packed. The problem increases with increasing storage time and warmer and wetter ambient climate. The invention can be remedied here by the packaging material consisting of paper or cardboard is coated according to the invention at least on the inside. In the case where cigarette packets are used which have a so-called inner liner, it is particularly advantageous to coat the inner liner on its inner side in accordance with the invention. (The innerliner is the inner, flexible shell of a package consisting of several nested casings, with the shell surrounding the inner liner made of a stiffer material.)

Claims

claims

1) Coating method for wrapping material made of paper or cardboard for smoking products or parts of tobacco products to reduce the tendency for this coating material to absorb and diffuse aqueous or oily substances, wherein the coating material is provided on the same side with two superimposed coatings, the In two coating processes, the liquid coating mixture consists of a coating material and a liquid volatile matrix, characterized in that the coating processes take place in two successive coating processes

at least one layer of a first coating material is applied in the first coating process, which reduces the receptivity of the paper or cardboard to the liquid volatile matrix of the second coating material,

in the second coating process at least one layer of a second coating material is applied, which is repellent or dense to one or more of the following substances, namely oils, fats, waxes, alcohols and water, wherein a different liquid volatile matrix is used for the first coating material than for the second coating material.

2) Coating method according to claim 1, characterized in that at least the first coating material is hydrophobic.

3) Coating method according to claim 1 or 2, characterized in that the liquid volatile matrix of the second coating material is water or an aqueous solution. 4) Coating method according to one of claims 1 to 3, characterized in that liquid volatile matrix of the first coating material is an organic solvent.

5) Coating method according to one of claims 1 to 4, characterized in that the second coating material is more hydrophobic than the first coating material.

6) Coating method according to one of claims 1 to 5, characterized in that the viscosity of the applied in the first coating operation liquid coating mixture is higher than that of the applied in the second coating operation liquid coating mixture.

7) Coating method according to one of claims 1 to 6, characterized in that

the viscosity of the liquid coating mixture applied in the first coating operation is dimensioned such that a flow time between 13 and 35 seconds, preferably between 18 and 22 seconds, results during the outlet cup test ISO 4 mm

the viscosity of the liquid coating mixture applied in the second coating process is such that a flow time between 11 and 23 seconds, preferably between 11 and 12 seconds, results during the outlet cup test ISO 4 mm

in the first coating operation, 1 to 6 g / m 2 dry application, preferably at least 3 g / m 2 dry application of the first coating material are applied, and

In the second coating process, 1 to 6 g / m 2 dry application, preferably 3 to 3.5 g / m 2 dry application of the second coating material, are applied.

8) Coating method according to one of claims 1 to 7, characterized in that - As coating mixture for the first coating process one or more of the paints shellac, ethylcellulose lacquer, nitrocellulose lacquer or Alkydharzlack is used or a lacquer with the said paints in terms of tightness and hydrophobicity-like physical properties and that

- Is used as a coating mixture for the second coating process styrene-acrylate varnish or a varnish with similar in terms of tightness and hydrophobicity physical properties.

Method according to one of claims 1 to 8, characterized in that at least one coating mixture additives and / or other components, such as in particular paraffin wax are added.

) Method according to one of claims 1 to 9, characterized in that the application of the two coatings in at least two coating devices (1.1, 1.2) takes place online on a continuous paper web (4), wherein each coating device (1.1, 1.2) a dryer unit consisting of infrared sources (3.1, 3.2, 3.3) and / or hot air sources (2.1, 2.2) is connected downstream.

A method according to any one of claims 1 to 10, characterized in that it is applied to an absorbent paper having a grammage of at most 80 g / m ² , preferably at most 40 g / m ² .

A method according to any one of claims 1 to 11, characterized in that the first and second coatings are applied to both sides of the paper or board.

) Covering material for tobacco products or parts of tobacco products characterized in that it is coated according to the coating method according to one of claims 1 to 12. Casing material according to claim 13, characterized in that it is the inner casing of a packaging consisting of several nested casings, in particular an inner liner for tobacco products, these tobacco products preferably being creté cigarettes.

Casing material according to claim 13, characterized in that it is a box for tobacco products, these tobacco products being preferably creté cigarettes.

Casing material according to claim 13, characterized in that it is the tipping paper of a cigarette or a cigarillo.

Mouthpiece covering paper according to claim 16, characterized in that it is mounted with the coated according to one of claims 1 to 12 side as the outside of a cigarette and that it has at least one further printing or coating over the coating formed according to one of claims 1 to 12 ,

) Mouthpiece covering paper according to claim 17, characterized in that the further printing or coating contains an aqueous, oily, waxy or alcoholic substance.

Mouthpiece covering paper according to claim 18, characterized in that the substance is a natural or artificial flavoring or its carrier.

Mouthpiece covering paper according to claim 19, characterized in that it is mounted with the coated according to one of claims 1 to 12 side as the inside of a cigarette containing an aqueous, oily, waxy or alcoholic substance. 21) Mouthpiece covering paper according to claim 20, characterized in that the aqueous, oily, waxy or alcoholic substance is present as a flavoring or excipient in one or more flavoring capsules.

22) Mouthpiece covering paper according to one of claims 16 to 21, characterized in that it comprises on both sides a coating formed according to one of claims 1 to 11.

23) Mouthpiece covering paper according to one of claims 16 to 22, characterized in that at least on one side of the coating formed according to one of claims 1 to 8 is interrupted at least on such a surface region of the mouthpiece covering paper, which for joining a cigarette or cigarillo from several items as Adhesive surface is used.

24) Mouthpiece paper according to claim 23, characterized in that the interruption of the coating is in the region in which the tipping paper on the finished cigarette overlaps with itself.

25) Mouthpiece covering paper according to one of claims 16 to 24, characterized in that the coating on the outside of the mouthpiece covering paper is applied to that region which is usually touched by the lips of the smoker, that is approximately to the longitudinal third of the tobacco rod facing away from tipping paper.