SHIELDING PAPER WITH INDICATOR USE FOR AEROSOL-PRODUCING OBJECTS

Abstract

The invention relates to a sheathing paper for an aerosol-generating article, wherein the paper comprises cellulose fibers and wherein a composition is provided to the paper, comprising a material that accelerates the thermal cleavage of the cellulose and a binder. The average air permeability of the sheathing paper is 10 cm3 / cm2-min-kPa) or more, the composition being provided only in some areas, comprising at least 0.5% and at most 70% of the sheathing paper area.

Description

Description COVERING PAPER WITH INDICATOR USE FOR AEROSOL-PRODUCING OBJECTS Invention Engineering Field The invention relates to an aerosol generating article, wherein the aerosol generating material is heated and the aerosol is then released, but the aerosol generating material does not burn. The aerosol generating article includes a wrapping paper wherein a substance is applied to the entire surface or to parts of the surface, which causes a change in the optical properties of the wrapping paper and thereby indicates that the aerosol generating article has been used. In particular, the wrapping paper of the aerosol generating article according to the invention is designed so that upon heating, its color changes irreversibly at least on parts of the surface, whereby particular attention is paid to the fact that the air permeability of the wrapping paper is minimally affected. The invention also relates to a process for manufacturing said wrapping paper. Background of the Invention In the previous technique, an aerosol generating device was known which included an aerosol generating material and a paper, which wrapped the aerosol generating material and thus formed a rod usually cylindrical in shape. In this case, the aerosol generating material is a material that releases aerosol upon application of heat, where the aerosol generating material is only heated, but not burned. In many cases, the aerosol generating device also includes a filter that can filter components from the aerosol and which is wrapped in a filter wrapping paper, and with a further wrapping paper that connects the filter to the rod wrapped with the aerosol generating material. During the intended use of an aerosol-generating device, it is common for the aerosol-generating material to be heated, but not ignited. This heating can be achieved, for example, by an external device into which the aerosol-generating device is inserted, or by a heat source applied to one end of the aerosol-generating device, which is operated to use the device, for example by ignition. In many cases, several aerosol-generating devices are contained in a single package, and often, after use, the used aerosol-generating device is returned to the package with the remaining unused aerosol-generating device. However, because the aerosol-generating material is only heated but not ignited, the used aerosol-generating device is not or only slightly optically distinguishable from the unused aerosol-generating device. In any case, the consumer cannot readily determine which aerosol-generating device has been used and which has not. Brief Description of the Invention The object of the invention is to provide a wrapping paper for an aerosol generating article that changes optically irreversibly during or immediately after use of the aerosol generating article, so that the aerosol generating article can be readily seen as having been used. The aerosol generating article in the context of the invention is a rod-shaped article comprising an aerosol generating material and a wrapping paper enclosing the aerosol generating material, wherein during its intended use, the aerosol generating material is only heated and does not burn. Heating without burning occurs for ordinary aerosol generating articles in any case where the aerosol generating article is heated to a temperature of up to 400°C. This object is achieved by means of wrapping paper for an aerosol generating article according to claim 1, an aerosol generating article comprising this wrapping paper according to claim 19 and a process for making wrapping paper according to the invention according to claim 21. The embodiment of the beneficial derivatives. provided on claims The inventors discovered that this object can be achieved by means of wrapping paper to which a special composition is applied over the entire surface or in parts and which, upon heating, causes an irreversible discoloration of the wrapping paper by accelerating the thermal decomposition of the cellulose. By means of this discoloration, used aerosol-generating articles can be distinguished from unused articles by simple inspection. It should be noted that in prior art, thermochromic inks are known which exhibit a color change when heated above a certain temperature, but these are deliberately not used in the present invention. One reason for this is that the color change of thermochromic inks is often reversible, so that the color disappears again upon cooling of the aerosol-generating article. In contrast, the decomposition of the cellulose in the wrapping paper according to the invention is in fact irreversible and therefore allows reliable identification of used aerosol-generating articles, even if some time has passed after use.Furthermore, the temperature at which color changes occur for known thermochromic inks is very low, so that even storing unused aerosol-generating items at high temperatures, for example in a parked car during the summer, can cause color changes, so that unused items can be confused with used ones. Furthermore, upon heating aerosol-generating items, temperatures of up to 400°C can be reached for a few minutes and at such temperatures, thermochromic inks can already partially decompose thermally, thereby losing their function. In addition, depending on the construction of the aerosol-generating object, air must flow through the wrapping paper into the aerosol-generating material during its use. However, thermochromic inks applied to wrapping paper can, in principle, reduce the air permeability of the wrapping paper, therefore an insufficient amount of color is often applied to the wrapping paper so as not to affect the function of the object. Finally, the materials that can be used for wrapping paper for aerosol-generating objects are in principle restricted by law in many countries, so the use of thermochromic inks, even if they are technically feasible, is often not permitted. In contrast to the known properties of thermochromic inks, the special inventive effect of the present invention consists in that the material used itself does not change its color, but preferably causes a color change of the cellulose in the wrapping paper. Wrapping paper must contain pulp fibers, with pulp fibers present in the wrapping paper at least 50% of the wrapping paper's mass. This is the minimum amount of pulp fiber necessary to create a visible color change. The wrapping paper has an average air permeability of at least 0 cm3 / (cm2-min-kPa) and at most 200 cm3 / (cm2-min-kPa). In this case, the air permeability is measured in accordance with ISO 2965:2009 with a measuring head with an open area of ​​2 mm χ 15 mm, where the average air permeability is determined from ten measurements at randomly selected positions on the wrapping paper. The composition provided for wrapping paper must contain at least one material that accelerates the thermal decomposition of cellulose to cause a color change, as well as a binder to fix the material in or on the paper. In this case, the material that accelerates the thermal decomposition of cellulose is suitable to cause an irreversible color change of the wrapping paper, visible to the naked eye, due to the thermal decomposition of cellulose in the paper upon heating the wrapping paper to a temperature of at least 130°C for 5 minutes. If the wrapping paper has an air permeability of more than 10 cm3 / (cm2-min-kPa), it is important that air can flow evenly over the surface through the wrapping paper so that larger areas of low air permeability can be avoided. Such areas of low air permeability can result from the use of the composition. Sufficient air permeability is ensured according to the invention by applying the composition only to portions of the wrapping paper, wherein the portions cover at least 0.5% and at most 70% of the wrapping paper surface. This means that the extent of the overall area over which air permeability is affected is limited, but it is also ensured that the area is large enough so that the color change is readily visible. In addition, the homogeneity of the air permeability is ensured according to the invention that the parts are suitably formed and arranged on the wrapping paper, wherein the suitability of the shape or arrangement is determined by two criteria for the purpose of the present invention, of which at least one must be satisfied. According to the first criterion, if the average air permeability of the wrapping paper is at least 10 cm3 / (cm2-min-kPa) and at most 20 cm3 / (cm2-min-kPa), the standard deviation of the air permeability must be at most 6 cm3 / (cm2-min-kPa), and if the average air permeability of the wrapping paper is at least 20 cm3 / (cm2-min-kPa) and at most 200 cm3 / (cm2-min-kPa), the coefficient of variation of the air permeability must be at most 30%. To determine the standard deviation and coefficient of variation of the air permeability, a measuring head with an aperture of 2 mm χ 15 mm was used and the standard deviation and coefficient of variation were determined from ten non-overlapping sections placed close to each other, so that for the determination of the mean value and standard deviation, an area of ​​approximately 300 mm2 was used. The coefficient of variation is then the quotient of the standard deviation and the mean value and is expressed as a percentage. The mean value used in this calculation will generally not be the same as the mean air permeability mentioned earlier, which was determined from measurements at ten randomly selected positions. As an alternative or as a complement to the specification of the dispersion parameter of air permeability, according to the second criterion, at an average air permeability of at least 10 cm3 / (cm2-min-kPa) and at most 200 cm3 / (cm2-min-kPa), it is also sufficient if the parts where the composition is administered on the wrapping paper are formed so that each imaginary circle with a diameter D mm on the wrapping paper contains at least one area where the composition is not administered, where the diameter of the circle D in mm is calculated from the average air permeability x in cm3 / (cm2-min-kPa) byn n(^mafcs—'—10) L' l'mafcs 190 and Dmax=12 mm and Dmin= 6 mm. The effect of this equation is that at low average air permeability, for example, 10 cm3 / (cm2-min-kPa), the circles can have a relatively large diameter of 12 mm and so the parts can contain a coarser structure. This is probably because at low air permeability, the environment of the parts where the material is applied is less important. At high air permeability, for example, 200 cm3 / (cm2-min-kPa), the circles can only have a relatively small diameter of 6 mm and the parts therefore need to have a finer structure, so that air continues to flow homogeneously across the surface of the wrapping paper. In summary, the inventors have invented a wrapping paper for aerosol-generating articles, - comprising pulp fibers, wherein at least 50% of the mass of the wrapping paper is formed by pulp fibers, - having an average air permeability of at least 0 cm3 / (cm2-min-kPa) and at most 200 cm3 / (cm2-min-kPa), measured with a 2 mm x 15 mm measuring head in accordance with ISO 2965:2009 at ten randomly selected positions, - wherein a composition has been provided which includes a material which accelerates the thermal decomposition of cellulose and a binder, and - wherein, in cases where the average air permeability of the wrapping paper is 10 cm3 / (cm2-min-kPa) or more, the composition is only applied to portions covering at least 0.5% and at most 70% of the surface of the wrapping paper, and wherein said portions in these cases, namely where the average air permeability of the wrapping paper is at least 10 cm3 / (cm2-min-kPa), are arranged on the wrapping paper in such a way that at least one of the following two criteria (1) and (2) is satisfied: (1) if the average air permeability of the wrapping paper is at least 10 cm3 / (cm2-min-kPa) and at most 20 cm3 / (cm2-min-kPa), then the standard deviation of the air permeability is at most 6 cm3 / (cm2-min-kPa), and if the average air permeability of the wrapping paper is at least 20 cm3 / (cm2-min-kPa) and at most 200 cm3 / (cm2,min'kPa), then the coefficient of variation is at most 30%, or (2) the parts where the composition is given are formed so that each imaginary circle with a diameter D mm on the wrapping paper contains at least one area where the composition is not given, where the diameter D in mm is calculated from the average air permeability x in cm3 / (cm2-min-kPa) byn n(^mafcs ' (Λ 1θ) L' l'mafcs 190 where Dmaks= 12 mm and Dmin= 6 mm. In this case, the average air permeability was determined as the average value of ten measurements at randomly selected positions on the wrapping paper. Individual measurements were carried out in accordance with ISO 2965:2009 with a measuring head with an aperture of 2 mm χ 15 mm. Thus, during the measurement, it can be neglected that the aperture can usually simultaneously cover the area where the composition is applied and the area where the composition is not applied. For the determination of the standard deviation and the coefficient of variation of the air permeability, ten measurements in accordance with ISO 2965:2009 are also carried out with a measuring head with an aperture of 2 mm × 15 mm, where the measurements are carried out on non-stacked sections placed close to each other, so that for the determination of the mean value and standard deviation, an area of ​​approximately 300 mm2 is used. The coefficient of variation is then the quotient of the standard deviation and the mean value of the determined measured values ​​and is expressed as a percentage. Preferably, the individual measuring sections are arranged so that their long sides, i.e., the 15 mm long sides, lie parallel exactly next to each other with a small distance between them, preferably at most 2 mm. Ordinary wrapping paper for aerosol-generating articles not in accordance with the invention with a naturally homogeneous air permeability over the entire surface has a coefficient of variation determined in this manner of at most 15%. In contrast, wrapping paper in which the composition has been applied to larger portions can have an air permeability coefficient of variation of 50% to 80%. This applies in particular if the composition is film-forming and thus closes the pores of the wrapping paper or if the composition is applied in the form of a tape several millimeters wide. The wrapping paper preferably has a basis weight of at least 15 g / m2, particularly preferably at least 18 g / m2 and particularly more preferably at least 20 g / m2. Such basis weight provides the wrapping paper with a tensile strength favorable for further processing of the wrapping paper on aerosol-generating articles. The wrapping paper preferably has a basis weight of at most 100 g / m2, particularly preferably at most 60 g / m2 and particularly at most 45 g / m2. The basis weight is preferably not so high that the recovery forces make wrapping of the aerosol-generating material difficult during the manufacture of the aerosol-generating article. The basis weight of wrapping paper includes the given composition and can be determined according to ISO 536:2012. Wrapping paper contains pulp fibers, wherein the pulp fibers constitute at least 50% of the mass of the wrapping paper and preferably at least 60% of the mass of the wrapping paper and particularly preferably at least 65% of the mass of the wrapping paper. Pulp fibers are required so that the effect of the material that accelerates the thermal decomposition of cellulose is easily visible optically due to the color change. Pulp fibers are sourced from one or more plants selected from the group consisting of coniferous trees, deciduous trees, spruce, fir, beech, birch, eucalyptus, flax, ramie, jute, abaca, sisal, kenaf and cotton. All or part of the pulp fibers may also be regenerated cellulose fibers, such as Tencel™ fibers, Lyocell™ fibers, viscose fibers or Modal™ fibers. Preferably, the pulp fibers are at least partially bleached, because the white color of the bleached pulp fibers makes color changes more easily visible. The proportion of unbleached pulp fibers, which are typically light to dark brown in color, is preferably at most 50% of the pulp fiber mass. The wrapping paper according to the invention may also contain one or more fillers. The total amount of fillers is preferably at most 40%, in particular preferably at least 10% and at most 38% and in particular at least 20% and at most 35% of the mass of the wrapping paper. The ratio of fillers preferably affects the air permeability, color and opacity of the wrapping paper, so that the color change upon heating of the aerosol generating article made thereof is easily visible. The filler or fillers are preferably white, water-insoluble particles and particularly preferably can be selected from the group consisting of calcium carbonate, magnesium carbonate, magnesium oxide, magnesium hydroxide, aluminum hydroxide, talc, kaolin and titanium dioxide. Wrapping paper may contain additional ingredients necessary for the manufacture of the wrapping paper or that give the wrapping paper further special properties. Examples of these ingredients are pigments, dyes, sizing agents, starches, retention aids, or processing aids, and these can be selected by a skilled person in terms of type and quantity based on his or her experience. Outside the parts to which the composition has been administered, the wrapping paper preferably cannot contain any material that accelerates the decomposition of cellulose, or solely in an amount, which does not exceed 0.5% by mass of the wrapping paper, in particular preferably 0.25% by mass of the wrapping paper and in particular 0.1% by mass of the wrapping per unit area. A higher ratio of this material will make it more difficult to detect a change in the color of the wrapping paper in comparison with the parts to which the composition has been administered. A composition including a binder and a material that accelerates the thermal decomposition of cellulose is applied to the entire surface or to parts of the wrapping paper. The amount of binder applied to the parts of the wrapping paper should be rather small, because the binder reduces the air permeability and increases the coefficient of variation of the air permeability. The amount of binder applied to the parts is preferably at most 15%, in particular preferably at most 10% and in particular at most 5% of the mass of the wrapping paper per unit area. Binders are preferably selected from the group consisting of starch, starch derivatives, cellulose derivatives, carboxymethyl cellulose, alginate, pectin, polyvinyl alcohol, guar, gum Arabic or mixtures thereof. The material that accelerates the thermal decomposition of cellulose is preferably contained, in the area of ​​the wrapping paper to which the composition containing it is provided, in an amount of at least 0.2 g / m2 and at most 8.0 g / m2, in particular preferably at least 0.3 g / m2 and at most 7.0 g / m2 and in particular more preferably at least 0.5 g / m2 and at most 5.0 g / m2. The amount of the material that accelerates the thermal decomposition of cellulose is chosen herein such that the color change is particularly readily visible, in particular to the naked eye, even under poor lighting conditions. Alternatively and preferably, the amount of a given material that accelerates the thermal decomposition of cellulose may be characterized in terms of a quantitative ratio of the amount of pulp fibers contained in the wrapping paper. The quantitative ratio is important because, according to the invention, the material must act on the pulp fibers. The quantitative ratio of the amount of said material in g / m2 to the area to which the composition containing it is administered and the amount of pulp fibers in the wrapping paper in g / m2 is preferably at least 0.05 and at most 0.45, in particular preferably at least 0.06 and at most 0.30 and in particular at least 0.07 and at most 0.25. The most advantageous ratio in each case depends on the specific material that accelerates the thermal decomposition of cellulose. The material that accelerates the thermal decomposition of cellulose is preferably one or more chemical compounds selected from the group consisting of citrate, malate, tartrate, acetate, nitrate, succinate, fumarate, gluconate, glycolate, lactate, oxylate, salicylate, α-hydroxy caprylate, hydrogen carbonate, carbonate, chloride, polyphosphate, phosphonate and phosphate and particularly preferably one or more chemical compounds selected from the group consisting of trisodium citrate, tripotassium citrate, monoammonium phosphate, sodium acetate, potassium acetate, sodium hydrogen carbonate, potassium hydrogen carbonate, sodium carbonate, potassium carbonate, sodium tartrate, potassium sodium tartrate, potassium formate, sodium formate, sodium nitrate and potassium nitrate. Particularly preferred, the material is one or more chemical compounds selected from the group consisting of tripotassium citrate, monoammonium phosphate, sodium hydrogen carbonate, sodium acetate and potassium carbonate.The chemical compounds favored in particular cause particularly clear discoloration of cellulose, as they favor the formation of charcoal particularly well as well. If the average air permeability of the wrapping paper is at least 10 cm3 / (cm2-min-kPa) and at most 200 cm3 / (cm2-min-kPa), then the portions to which the composition has been provided are formed so that they make up at least 0.5% and at most 70%, preferably at least 1% and at most 60%, especially preferably at least 1% and at most 20% and especially more preferably at least 1% and at most 10% of the surface of the wrapping paper. If the average air permeability of the wrapping paper is at least 10 cm3 / (cm2-min-kPa) and at most 200 cm3 / (cm2-min-kPa), then the parts must be formed so that at least one of the following two criteria (3), (4) is met: (3) if the average air permeability of the wrapping paper is greater than 10 cm3 / (cm2-min-kPa) and less than 20 cm3 / (cm2-min-kPa), then the standard deviation of the air permeability is at most 6 cm3 / (cm2-min-kPa), preferably at most 5.5 cm3 / (cm2-min-kPa) and in particular preferably at most 5 cm3 / (cm2-min-kPa), and if the average air permeability of the wrapping paper is at least 20 cm3 / (cm2-min-kPa) and in particular at most 200 cm3 / (cm2-min-kPa), then the coefficient of variation of the air permeability is at most 30%, preferably at most 27.5% and in particular at most 25%, or (4) the parts to which the composition is given are formed so that each imaginary circle with a diameter D mm on the wrapping paper contains at least one area to which the composition is not given, wherein the diameter D in mm can be calculated from the air permeability average x in cm3 / (cm2-min-kPa) byn_n(^mafcs ' (Λ 1θ) L' l'mafcs 190 and where Dmaks= 12 mm and Dmin= 6 mm, preferably Dmaks= 10 mm and Dmin= 5 mm and especially preferably Dmaks= 8 mm and Dmin= 4 mm and especially preferably Dmaks= 6 mm and Dmin= 3 mm. If the average air permeability of the wrapping paper is at least 0 cm3 / (cm2-min-kPa) and at most 10 cm3 / (cm2-min-kPa), the composition may be applied to the entire surface or to parts. In the case of application to parts, the parts to which the composition is applied on the wrapping paper are preferably formed so that each imaginary circle on the wrapping paper with a diameter of 12 mm, in particular preferably with a diameter of 10 mm and in particular with a diameter of 8 mm contains at least one area to which the composition is not applied. If the average air permeability of the wrapping paper is at least 0 cm3 / (cm2-min-kPa) and at most 10 cm3 / (cm2-min-kPa) and the composition is only provided on parts, then the parts to which the composition is provided are formed so that they preferably constitute at least 0.5% and at most 70%, in particular preferably at least 1% and at most 60% and in particular at least 1% and at most 20% and in particular at least 1% and at most 10% of the surface of the wrapping paper. The smaller the area over which the composition is applied, the less the air permeability of the wrapping paper will be affected in terms of its average value and its coefficient of variation, but conversely, the individual areas over which the color change can be seen will also be smaller accordingly and so it will be more difficult to recognize the aerosol-generating object made from it that has been used. Criteria (3) and (4) are not equivalent in their effect, meaning that the fulfillment of one of the criteria does not necessarily cause the fulfillment of the other criterion, but each by itself is sufficient to obtain wrapping paper according to the invention that is particularly suitable for use on aerosol-generating objects. The same applies to the previously mentioned criteria (1) and (2). The aerosol generating article according to the invention is rod-shaped and includes an aerosol generating material and wrapping paper according to the invention, wherein the wrapping paper encloses the aerosol generating material and wherein during the intended use of the aerosol generating article, the aerosol generating material is only heated, but not burned. In a preferred embodiment of the aerosol generating article, the aerosol generating material is heated to a maximum temperature of at least 120°C and at most 500°C and particularly preferably to a maximum temperature of at least 200°C and at most 400°C. In a preferred embodiment, the aerosol generating device may additionally include a filter. Wrapping paper according to the invention can be prepared in a process according to the invention comprising the following steps A-A: A - providing a base wrapping paper, B - providing a composition to the base wrapping paper, and C - drying the wrapping paper obtained in step B, wherein the wrapping paper obtained in step C includes pulp fibers, wherein at least 50% of the mass of the wrapping paper is formed by pulp fibers, and the wrapping paper obtained in step C has an average air permeability of at least 0 cm3 / (cm2-min-kPa) and at most 200 cm3 / (cm2-min-kPa), as measured with a 2 mm x 15 mm measuring head in accordance with ISO 2965:2009, and at step B, a composition is provided which includes a material that accelerates the thermal decomposition of cellulose and a binder, and which, if the average air permeability of the wrapping paper obtained in step C is at least 10 cm3 / (cm2-min-kPa) and at most 200 cm3 / (cm2-min-kPa),applied in step B to an area covering at least 0.5% and at most 70% of the surface of the wrapping paper, and wherein, if the average air permeability of the wrapping paper obtained in step C is at least 10 cm3 / (cm2-min-kPa) and at most 200 cm3 / (cm2-min-kPa), the wrapping paper obtained in step C meets at least one of the following two criteria (1), (2):, (1) if the average air permeability of the wrapping paper obtained in step C is at least 10 cm3 / (cm2-min-kPa) and at most 20 cm3 / (cm2-min-kPa), then the standard deviation of the air permeability is at most 6 cm3 / (cm2-min-kPa), and if the average air permeability of the wrapping paper obtained in step C is at least 20 cm3 / (cm2 -min-kPa) and at most 200 cm3 / (cm2,min'kPa), then the coefficient of variation of the air permeability is at most 30%, or (2) the parts to which the composition is given in step B are formed so that each imaginary circle with a diameter of D mm on the wrapping paper contains at least one area to which the composition is not given, where the diameter D in mm is calculated from the average air permeability x in cm3 / (cm2-min-kPa) of the wrapping paper obtained in step C byn n(^mafcs—'—10) l'—L-'max4 nand Dmax= 12 mm and Dmin= 6 mm. Regarding the properties and components of the wrapping paper obtained in step C, the same required, preferred, particularly preferred and particularly preferred range of values ​​and properties apply as already mentioned for the wrapping paper according to the invention. This applies in particular to the basis weight, standard deviation and coefficient of variation of the air permeability, type and amount of pulp fibers, type and amount of filler and design of the parts to which the composition is given, for example their ratio to the total surface of the wrapping paper and the selection of the parameters DmaxSand Dmin. The composition given in stage B includes a material that accelerates the thermal decomposition of cellulose, a binder and a solvent, where the solvent is preferably water. The material in the composition at stage B that accelerates the thermal decomposition of cellulose is a chemical compound or a mixture of two or more chemical compounds and is preferably dissolved in the solvent of the composition. The material that accelerates the thermal decomposition of cellulose contained in the composition of step B is preferably one or more chemical compounds selected from the group consisting of citrate, malate, tartrate, acetate, nitrate, succinate, fumarate, gluconate, glycolate, lactate, oxylate, salicylate, α-hydroxycaprylate, hydrogen carbonate, carbonate, chloride, polyphosphate, phosphonate, and phosphate and particularly preferably one or more chemical compounds selected from the group consisting of trisodium citrate, tripotassium citrate, monoammonium phosphate, sodium acetate, potassium acetate, sodium hydrogen carbonate, potassium hydrogen carbonate, sodium carbonate, potassium carbonate, sodium tartrate, potassium sodium tartrate, potassium formate, sodium formate, sodium nitrate and potassium nitrate. Particularly preferred, the material is one or more of the chemical compounds selected from the group consisting of tripotassium citrate, monoammonium phosphate, sodium hydrogen carbonate, sodium acetate and potassium carbonate. The composition provided to the base wrapping paper in step B contains a material that accelerates the thermal decomposition of cellulose in an amount preferably at least 3% and at most 30%, in particular preferably at least 4% and at most 25% and in particular at least 5% and at most 20%, respectively, of the mass of the composition. The binder in the composition of stage B is preferably selected from the group consisting of starch, starch derivatives, cellulose derivatives, carboxymethyl cellulose, alginate, pectin, polyvinyl alcohol, guar, gum Arabic or mixtures thereof. The composition provided to the base wrapping paper in step B contains a binder in an amount preferably at least 0.1% and at most 15%, in particular preferably at least 0.3% and at most 12% and in particular at least 0.5% and at most 10%, respectively, of the amount of the composition. The amount of binder in this case also depends on the requirements of the use process in step B, in particular with regard to the viscosity of the composition. During drying in step C, the solvent is principally removed from the composition and, the given dry composition is then applied in an amount of preferably at least 0.2 g / m2 and at most 8 g / m2, in particular preferably at least 0.5 g / m2 and at most 6 g / m2 and in particular at least 1 g / m2 and at most 5 g / m2 to the area to which the composition is actually applied. Application at stage B can be carried out by various processes, of which printing and spraying are preferred and rotogravure printing and flexographic printing are particularly preferred. The drying process at stage C can be carried out by various processes, preferably by contacting one or more heated cylinders, contacting with hot air, infrared radiation, microwave radiation and combinations thereof. In a particularly preferred embodiment of the process according to the invention, after step C, the process includes additional steps D and E, wherein in step D, water is applied to the entire surface of the wrapping paper obtained in step C and in step E, the wrapping paper from step D is dried, particularly preferably by contacting with one or more heated cylinders. During the application of the composition in step B, particularly if the solvent contains water, wrinkles may occur after drying in step C. By means of steps D and E of the particularly preferred embodiment of the process according to the invention, such wrinkles can be significantly reduced or completely avoided. Short Description of Image Figure 1 shows, as an example, wrapping paper and the positions where ten measurements for determining the standard deviation and coefficient of variation of air permeability can be made. Complete Description of the Invention In the following, some preferred embodiments of the wrapping paper according to the invention are described. As the base wrapping paper in stage A of the process according to the invention, two papers marked as base wrapping paper A and base wrapping paper B are used. Base wrapping paper A has a basis weight of 29 g / m2 and contains 69% wood pulp fiber and 31% precipitated calcium carbonate as filler. The percentages in this case refer to the mass of the base wrapping paper. Wood pulp fiber is a mixture of pulp fibers sourced from coniferous and deciduous trees. Base wrapping paper A has an average air permeability of 60.1 cm3 / (cm2-min-kPa), where the air permeability is measured in accordance with ISO 2965:2009 with a measuring head with an aperture of 2 mm x 15 mm at ten randomly selected positions, and the average value is calculated from these ten measurements. Base wrapping paper B has a basis weight of 24 g / m2 and contains 71% wood pulp fiber and 29% precipitated calcium carbonate as filler. The percentages in this case refer to the mass of the base wrapping paper. Wood pulp fiber is a mixture of pulp fibers sourced from coniferous and deciduous trees. Base wrapping paper B has an average air permeability of 74.8 cm3 / (cm2-min-kPa), where the air permeability is measured in accordance with ISO 2965:2009 with a measuring head with an aperture of 2 mm x 15 mm at ten randomly selected positions, and the average value is calculated from these ten measurements. The different compositions are applied by rotogravure printing on the base wrapping papers A and B in sections in the form of a cross-hatched pattern, 1.5 mm wide, so that the sections on which the compositions are applied constitute approximately 40% of the area of ​​the base wrapping paper. The amount of composition applied to the parts is 30 g / m2 for base wrapping paper A and 25 g / m2 for base wrapping paper B to the area where the composition is actually applied. The wrapping paper is then dried according to step C of the process according to the invention. The parameters related to the manufacture of wrapping paper are provided in Table 1, Column No. indicates the wrapper number, column BP indicates the base wrapping paper used for manufacture. Under the column Composition, binders and materials that accelerate the thermal decomposition of cellulose are provided as % to the mass of the composition. The type of binder is provided, where CMC means carboxymethyl cellulose and St means starch. The type of material is also provided, where TKZ means tripotassium citrate, MAP means monoammonium phosphate, NaAc means sodium acetate and KCrb means potassium carbonate. Under the column Wrapping paper, the amounts of binders and materials that accelerate the thermal decomposition of cellulose are provided in g / m2 and as % to the basis weight of the wrapping paper, as is the ratio V of the amount of these materials in g / m2 to the amount of pulp fiber in the wrapping paper in g / m2. Composition Wrapping paper Binder Material Binder Material V No. BP % Art % Art g / m2 % g / m2 % 1 A 0.71 CMC 5.0 TKZ 0.21 0.69 1.50 4.88 0.07 2 A 0.68 CMC 8.7 TKZ 0.20 0.64 73 2.60 MC 8 10.0 TKZ 0.21 0.65 3.00 9.31 0.15 4 A 0.65 CMC 12.0 TKZ 0.20 0.59 3.60 10.98 0.18 5 A 0.63 CMC 14.51 0.61 24.0 0.22 6 A 0.71 CMC 5.0 MAP 0.21 0.69 1.50 4.88 0.07 7 A 0.68 CMC 8.7 MAP 0.20 0.64 2.61 8.20 0.13 8 A 0.70 CMC 3.00 9.31 0.15 9 ​​A 0.65 CMC 12.0 MAP 0.20 0.59 3.60 10.98 0.18 10 A 0.63 CMC 14.8 MAP 0.19 0.56 4.40 1 0 CMC 13.20 NaAc 0.21 0.68 1.50 4.88 0.07 12 A 0.70 CMC 10.0 NaAc 0.21 0.65 3.00 9.31 0.15 13 B 0.75 CMC 10.0 235 0.79 14 B 0.75 CMC 25.0 KCrb 0.19 0.62 6.25 20.53 0.37 15 B 0.70 CMC 30.0 KCrb 0.18 0.55 C 7.50 23.68 0.25 KS 50.16 B 4.59 2.00 7.34 0.12 17 B 5.00 St 25.0 KCrb 1.25 3.97 6.25 19.84 0.37 18 B 5.00 CMC 25.0 KCrb 1.25, 825 16 Regarding the basic wrapping papers A and B the air permeability was measured at ten randomly selected positions according to ISO 2965:2009 with a measuring head with an aperture of 2 mm χ 5 15 mm and the average value was calculated from it. For wrapping papers 1 to 12, made from basic wrapping paper A, an average air permeability between 42 cm3 / (cm2-min-kPa) and 48 cm3 / (cm2-min-kPa) was found, while the average air permeability of wrapping papers 13 to 18, made from 10 basic wrapping papers B, was between 50 cm3 / (cm2-min-kPa) and 55 cm3 / (cm2-min-kPa). For the test of criteria (1) or (3), the coefficient of variation of the air permeability is determined in accordance with ISO 2965:2009 with a measuring head with an aperture of 2 mm x 15 mm. The measurement method is described with reference to Figure 1, with wrapping paper 1 in Figure 1, the composition is given in the form of a crosshair 2 and the measuring head with an aperture of 2 mm x 15 mm is placed at ten adjacent positions 3a to 3j, where each individual position is shifted by 3 mm, resulting in a distance of 1 mm between the areas. The air permeability is measured at each position 3a to 3j. From this, the mean value and standard deviation are determined and the coefficient of variation is calculated. For wrapping papers 1 to 12 made from base wrapping paper A, a coefficient of variation between 10% and 15% is obtained and for wrapping papers 13 to 18 made from base wrapping paper B, the coefficient of variation is between 12% and 17%, so that criteria (1) and (3) are met. For test criteria (2) and (4), the diameter of the imaginary circle was determined for each of the wrapping papers 1 to 18 based on the measured average air permeability. For wrapping paper 1 to 12, made from base wrapping paper A, based on an average air permeability of 42 cm3 / (cm2-min-kPa) to 48 cm3 / (cm2-min-kPa), the result is a circle diameter of (12 - 6) (42 - 10) 11.0 mm to D = 12(12 - 6) (48 - 10) 10.8 mm For wrapping paper 13 to 18 made from base wrapping paper B, based on an average air permeability of 50 cm3 / (cm2-min-kPa) to 55 cm3 / (cm2-min-kPa), the result is the diameter of the circle from to D = 12 (12 - 6) (50 - 10) 190 10.7 mm D = 12 (12 - 6) (55 - 10) 190 10.6 mm The pattern with cross lines with a width of 1.5 mm clearly meets the requirements of criteria (2) and (4) and so this criterion is met for all wrapping papers 1 to 18. Wrapping papers 1 to 18 were heated at 130°C for 5 minutes. After only one minute, a color change was observed in wrapping papers 1, 3, 6, 8, 11, 12, 13 and 17, after 5 minutes, all wrapping papers according to the invention showed, a significant irreversible color change to a yellowish color in the parts where the composition was applied, and for longer heating periods the color changed from light brown to dark brown, which can be clearly seen from the unchanged or hardly changed color outside of these parts. The aerosol-generating body, according to the previous technique, is made from wrapping paper heated in a heater, as intended. After removing the aerosol-generating body from the heater, a distinct color change can be seen in the printed parts, so that the used and unused aerosol-generating bodies can be clearly distinguished from each other.

Claims

Claim 1. Wrapping paper for aerosol-generating articles, comprising pulp fibers, wherein at least 50% of the mass of the wrapping paper is formed by pulp fibers, having an average air permeability of at least 0 cm3 / (cm2-min-kPa) and at most 200 cm3 / (cm2-min-kPa), as measured with a 2 mm χ 15 mm measuring head in accordance with ISO 2965:2009 at ten randomly selected positions, and wherein the composition is provided comprising a material that accelerates the thermal decomposition of cellulose and a binder, wherein the material that accelerates the thermal decomposition of cellulose is capable of causing an irreversible discoloration of the wrapping paper due to the thermal decomposition of cellulose in the paper that is visible to the naked eye upon heating the wrapping paper at a temperature of at least 130°C for 5 minutes, wherein, in the case where the average air permeability of the wrapping paper is 10 cm3 / (cm2-min-kPa) or more,said composition is only applied to portions covering at least 0.5% and at most 70% of the surface of the wrapping paper, and wherein said portions in this case are arranged on the wrapping paper such that furthermore, at least one of the following criteria (1), (2) is satisfied: (1) if the average air permeability of the wrapping paper is at least 10 cm3 / (cm2-min-kPa) and at most 20 cm3 / (cm2-min-kPa), then the standard deviation of the air permeability is at most 6 cm3 / (cm2-min-kPa), wherein the standard deviation is determined from ten measurements with the 2 mm χ 15 mm measuring head on non-overlapping areas placed close to each other, and if the average air permeability of the wrapping paper is at least 20 cm3 / (cm2-min-kPa) and at most 200 cm3 / (cm2-min-kPa), then the coefficient of variation of the air permeability is at most 30%,wherein the coefficient of variation is defined as the quotient of the standard deviation and the mean value of the ten measurements from which the standard deviation is determined, (2) the sections where the composition is given are formed so that each imaginary circle with diameter D mm on the wrapping paper contains at least one area where the composition is not given, wherein the diameter D in mm is calculated from the mean air permeability x in cm3 / (cm2-min-kPa) by nn (^mafcs — ' — 10) h' — Umaks 4 ci n where Dmaks = 12 mm and Dmin = 6 mm, wherein the mean air permeability x corresponds to the mean value of the ten measurements at randomly selected positions on the wrapping paper., 2. The wrapping paper according to claim 1, having a basis weight of at least 15 g / m2, preferably at least 18 g / m2 and particularly preferably at least 20 g / m2.

3. Wrapping paper according to said claim 1 or 2, having a basis weight of at most 100 g / m2, preferably at most 60 g / m2 and particularly preferably at most 45 g / m2.

4. Wrapping paper according to any one of the foregoing claims, wherein the pulp fibers constitute at least 60% of the mass of the wrapping paper and preferably at least 65% of the mass of the wrapping paper.

5. Wrapping paper according to any one of the foregoing claims, wherein the pulp fiber is sourced from one or more plants selected from the group consisting of conifers, deciduous trees, spruce, fir, beech, birch, eucalyptus, flax, hemp, jute, ramie, abaca, sisal, kenaf and cotton.

6. Wrapping paper according to any one of the foregoing claims, wherein at least a portion of the pulp fibers is bleached, wherein the proportion of unbleached pulp fibers, if any, is preferably at most 50% by mass of the pulp fibers.

7. Wrapping paper according to any one of the foregoing claims, containing one or more fillers, wherein the total amount of fillers constitutes at most 40%, preferably at least 10% and at most 38% and particularly preferably at least 20% and at most 35% of the mass of the wrapping paper.

8. Wrapping paper according to claim 7, wherein the filler is formed by water-insoluble particles, is white and is preferably selected from the group consisting of calcium carbonate, magnesium carbonate, magnesium oxide, magnesium hydroxide, aluminum hydroxide, talc, kaolin, titanium dioxide.

9. Wrapping paper according to any one of the foregoing claims, containing no material that accelerates the decomposition of cellulose outside the parts to which the composition has been given, or only in an amount not exceeding 0.5% by mass of the wrapping paper, preferably 0.25% by mass of the wrapping paper and particularly preferably 0.1% by mass of the wrapping paper per unit area.

10. Wrapping paper according to any one of the foregoing claims, wherein the amount of binder provided to the portions of the wrapping paper is at most 15%, preferably at most 10% and particularly preferably at most 5% of the mass of the wrapping paper per unit area.

11. Wrapping paper according to any one of the foregoing claims, wherein the binder is selected from the group consisting of starch, starch derivatives, cellulose derivatives, carboxymethyl cellulose, alginate, pectin, polyvinyl alcohol, guar, gum Arabic or mixtures thereof.

12. Wrapping paper according to any one of the foregoing claims, wherein the material accelerating the thermal decomposition of cellulose is contained in the area of the wrapping paper wherein the composition is contained therein in an amount of at least 0.2 g / m2 and at most 8.0 g / m2, preferably at least 0.3 g / m2 and at most 7.0 g / m2 and particularly preferably at least 0.5 g / m2 and at most 5.0 g / m2.

13. Wrapping paper according to any one of the foregoing claims, wherein the ratio of the amount of the material accelerating the thermal decomposition of cellulose in g / m2 to the area where the composition comprises is given and the amount of pulp fiber in the wrapping paper in g / m2 is at least 0.05 and at most 0.45, preferably at least 0.06 and at most 0.30 and particularly preferably at least 0.07 and at most 0.

25.

14. Wrapping paper according to any one of the preceding claims, wherein the material accelerating the thermal decomposition of cellulose is one or more chemical compounds selected from the group consisting of citrate, malate, tartrate, acetate, nitrate, succinate, fumarate, gluconate, glycolate, lactate, oxylate, salicylate, αhydroxycaprylate, hydrogen carbonate, carbonate, chloride, polyphosphate, phosphonate and phosphate, preferably one or more chemical compounds selected from the group consisting of trisodium citrate, tripotassium citrate, monoammonium phosphate, sodium acetate, potassium acetate, sodium hydrogen carbonate, potassium hydrogen carbonate, sodium carbonate, potassium carbonate, sodium tartrate, potassium sodium tartrate, potassium formate, sodium formate, sodium nitrate and potassium nitrate, wherein the material is particularly preferably one or more chemical compounds selected from the group consisting of tripotassium citrate, monoammonium phosphate, sodium hydrogen carbonate, sodium acetate and potassium carbonate.

15. Wrapping paper according to any one of the preceding claims, wherein, in the case where the average air permeability of the wrapping paper is at least 10 cm3 / (cm2-min-kPa) and at most 200 cm3 / (cm2-min-kPa), the portions to which the composition is provided are formed so that they constitute at least 1% and at most 60%, preferably at least 1% and at most 20% and especially preferably at least 1% and at most 10% of the surface of the wrapping paper.

16. Wrapping paper according to any one of the preceding claims wherein, in the case where the average air permeability of the wrapping paper is at least 10 cm3 / (cm2-min-kPa) and at most 200 cm3 / (cm2-min-kPa), the portions are formed so that at least one of the following two criteria (3), (4) is satisfied: (3) if the average air permeability of the wrapping paper is greater than 10 cm3 / (cm2-min-kPa) and less than 20 cm3 / (cm2-min-kPa), then the standard deviation of the air permeability is at most 5.5 cm3 / (cm2,min'kPa), and preferably at most 5 cm3 / (cm2,min'kPa), and if the average air permeability of the wrapping paper is at least 20 cm3 / (cm2-min-kPa) and at most 200 cm3 / (cm2-min-kPa), then the coefficient of variation of the air permeability is 27.5% and most liked by 25%,or (4) the parts to which the composition is administered are formed so that each imaginary circle with a diameter D mm on the wrapping paper contains at least one area to which the composition is not administered, where the diameter D in mm is calculated from the average air permeability x in cm3 / (cm2-min-kPa) by nn (^mafcs — ' — 10) L' l'mafcs 4 ci n and where Dmax = 10 mm and Dmin = 6 mm, preferably Dmax = 8 mm and Dmin = 4 mm, especially preferably Dmax = 6 mm and Dmin = 3 mm., 17. Wrapping paper according to any one of the preceding claims wherein, in the case where the average air permeability of the wrapping paper is at least 0 cm3 / (cm2-min-kPa) and at most 10 cm3 / (cm2-min-kPa), the composition is applied on the entire surface or on parts, wherein, in the case of application on parts, the parts where the composition is applied on the wrapping paper are preferably formed so that each imaginary circle with a diameter of 12 mm, preferably with a diameter of 10 mm and especially preferably with a diameter of 8 mm on the wrapping paper contains at least one area where the composition is not applied.

18. Wrapping paper according to any one of the foregoing claims wherein, in the case where the average air permeability of the wrapping paper is at least 0 cm3 / (cm2-min-kPa) and at most 10 cm3 / (cm2-min-kPa) and the composition is only provided in portions, the portions to which the composition is provided are formed so that they preferably constitute at least 0.5% and at most 70%, preferably at least 1% and at most 60%, in particular preferably at least 1% and at most 20% and in particular at least 1% and at most 10% of the surface of the wrapping paper.

19. An aerosol generating article, rod-shaped, comprising an aerosol generating material and a wrapping paper according to any one of claims 1 to 18, wherein the wrapping paper encloses the aerosol generating material and wherein during the intended use of the aerosol generating article, the aerosol generating material is only heated, but not burned.

20. An aerosol generating article, rod-shaped, according to said claim 19, wherein during the intended use, the aerosol generating material is heated to a maximum temperature of at least 120°C and at most 500°C and preferably to a maximum temperature of at least 200°C and at most 400°C, and / or which contains a filter.

21. A process for producing wrapping paper for aerosol-generating objects, comprising stages A to C: A - providing a base wrapping paper, B - providing a composition to the base wrapping paper, and C - drying the wrapping paper obtained in stage B, wherein the wrapping paper obtained after stage C includes pulp fibers, wherein at least 50% of the mass of the wrapping paper is formed by pulp fibers, and the wrapping paper obtained after stage C has an average air permeability of at least 0 cm3 / (cm2-min-kPa) and at most 200 cm3 / (cm2-min-kPa), as measured with a 2 mm x 15 mm measuring head in accordance with ISO 2965:2009, and in stage B, a composition is provided which includes a material that accelerates the thermal decomposition of cellulose and a binder,wherein the material accelerating the thermal decomposition of cellulose is capable of causing an irreversible color change of the wrapping paper due to the thermal decomposition of cellulose in the paper that is visible to the naked eye upon heating the wrapping paper at a temperature of at least 130°C for 5 minutes, and wherein, if the average air permeability of the wrapping paper obtained in step C is at least 10 cm3 / (cm2-min-kPa) and at most 200 cm3 / (cm2-min-kPa), in step B the composition is applied only to portions covering at least 0.5% and at most 70% of the surface of the wrapping paper, and wherein, if the average air permeability of the wrapping paper obtained in step C is at least 10 cm3 / (cm2-min-kPa) and at most 200 cm3 / (cm2-min-kPa), the wrapping paper obtained in step C meets at least one of the criteria (1),(2) as follows: (1) if the average air permeability of the wrapping paper obtained in stage C is at least 10 cm3 / (cm2-min-kPa) and at most 20 cm3 / (cm2-min-kPa), then the standard deviation of the air permeability is at most 6 cm3 / (cm2-min-kPa); and if the average air permeability of the wrapping paper obtained in step C is at least 20 cm3 / (cm2 -min-kPa) and at most 200 cm3 / (cm2-min-kPa), then the coefficient of variation of the air permeability is at most 30%, or (2) the parts to which the composition is given in step B are formed so that each imaginary circle with a diameter of D mm on the wrapping paper contains at least one area to which the composition is not given, where the diameter D in mm is calculated from the average air permeability x in cm3 / (cm2-min-kPa) of the wrapping paper obtained after step C by nn (^mafcs — ^min) ' — 10) h' — Umaks 4 nn and where Dmaks = 12 mm and Dmin = 6 mm., 22. The process according to claim 21, wherein the composition provided in step B includes a material that accelerates the thermal decomposition of cellulose, a binder and a solvent, wherein the solvent is preferably water.

23. The process according to claim 22, wherein the agent that accelerates the thermal decomposition of cellulose in the composition of step B is a chemical compound or a mixture of two or more chemical compounds and is dissolved in a solvent of the composition.

24. The process according to any one of claims 21 to 23, wherein the agent accelerating the thermal decomposition of cellulose contained in the composition of step B is one or more chemical compounds selected from the group consisting of citrate, malate, tartrate, acetate, nitrate, succinate, fumarate, gluconate, glycolate, lactate, oxylate, salicylate, α-hydroxycaprylate, hydrogen carbonate, carbonate, chloride, polyphosphate, phosphonate and phosphate, and preferably one or more chemical compounds selected from the group consisting of trisodium citrate, tripotassium citrate, monoammonium phosphate, sodium acetate, potassium acetate, sodium hydrogen carbonate, potassium hydrogen carbonate, sodium carbonate, potassium carbonate, sodium tartrate, potassium sodium tartrate, potassium formate, sodium formate, sodium nitrate and potassium nitrate, wherein the agent is particularly preferably one or more chemical compounds selected from the group consisting of tripotassium citrate, monoammonium phosphate, sodium hydrogen carbonate,sodium acetate and potassium carbonate., 25. The process according to any one of claims 21 to 24, wherein the composition provided to the base wrapping paper in step B contains a material that accelerates the thermal decomposition of cellulose in an amount of at least 3% and at most 30%, preferably at least 4% and at most 25% and particularly preferably at least 5% and at most 20%, respectively, of the mass of the composition.

26. The process according to any one of claims 21 to 25, wherein the binder in the composition of step B is selected from the group consisting of starch, starch derivatives, cellulose derivatives, carboxymethyl cellulose, alginate, pectin, polyvinyl alcohol, guar, gum Arabic or mixtures thereof.

27. The process according to any one of claims 21 to 26, wherein the composition applied to the wrapping paper at step B contains a binder in an amount of at least 0.1% and at most 15%, preferably at least 0.3% and at most 12% and particularly preferably at least 0.5% and at most 10%, respectively, of the amount of the composition.

28. The process according to any one of claims 21 to 27, wherein during drying at step C, the solvent is principally removed from the composition and the dried composition is thereafter administered in an amount of at least 0.2 g / m2 and at most 8 g / m2, preferably at least 0.5 g / m2 and at most 6 g / m2 and particularly preferably at least 1 g / m2 and at most 5 g / m2, respectively, with respect to the area to which the composition is actually administered.

29. The process according to any one of claims 21 to 28, wherein the application of the composition in step B is carried out by molding or drying, preferably by rotogravure molding or flexographic molding.

30. The process according to any one of claims 21 to 29, wherein the drying process at stage C is carried out by contacting with one or more heated cylinders, by contacting with hot air, by infrared radiation, microwave radiation or combinations thereof.

31. The process according to any one of claims 21 to 30, wherein the process further comprises additional steps D and E after step C, wherein in step D, water is applied to the entire surface of the wrapping paper obtained in step C and in step E, the wrapping paper from step D is dried, preferably by contacting with one or more heated cylinders.

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