Moisture-absorbing wrappers for aerosol-generating articles

Abstract

The present invention relates to an aerosol-generating article (10) comprising a plurality of elements and a stick wrap configured to connect the elements to form the aerosol-generating article, the aerosol-generating article being further configured to display a visually perceptible marking (60) upon contact of the stick wrap with moisture. The present invention also relates to an aerosol generation system comprising an aerosol generating device and the aerosol-generating article. The present invention also relates to a method of manufacturing an aerosol-generating article, comprising providing a plurality of elements and providing a stick wrap that connects the elements by wrapping the stick wrap around a rod-shaped element to form the aerosol-generating article, the aerosol-generating article being configured to display a visually perceptible marking upon contact of the stick wrap with moisture.

Description

[Technical Field]

[0001] The present invention relates to an aerosol-generating article comprising a moisture-absorbing wrapper. The present invention also relates to an aerosol-generating system comprising the aerosol-generating article, and a method for manufacturing the aerosol-generating article. [Background technology]

[0002] One type of aerosol generating system is an electrically operated aerosol generating system. Known handheld electrically operated aerosol generating systems typically include an aerosol generating device that includes a battery, control electronics, and an electric heater for heating an aerosol-generating article specifically designed for use with the aerosol generating device. The aerosol-generating article includes an aerosol-forming substrate. In some embodiments, the aerosol-forming substrate is in the form of a plug, such as a cigarette plug, and an electric heater contained within the aerosol-generating device is inserted into the aerosol-forming substrate when the smoking article is inserted into the aerosol-generating device.

[0003] Typically, such aerosol-generating articles are made from a combination of multiple rod-shaped elements, which may also be referred to as plugs. Each plug may be wrapped with plug wrap. Stick wrap may be used to connect the individual rod-shaped elements to form an elongated aerosol-generating article. The proximal end of the aerosol-generating article is intended to contact the user's lips. The distal end of the aerosol-generating article is intended to be inserted into the interior of an aerosol-generating device and heated to generate an inhalable aerosol. The aerosol-generating article may include a substrate plug at its distal end that holds an aerosol-forming substrate, and a mouthpiece filter (MPF) at its proximal end. Another plug may be provided between the substrate plug and the mouthpiece filter. Such a plug may be, for example, a cardboard tube, a cooling element made of polylactic acid (PLA), or a hollow acetate tube (HAT).

[0004] Electrically heated aerosol-generating articles are also referred to as heat-and-burn (HnB) articles because they are heated but not burned during consumption. HnB articles may not necessarily change their appearance during consumption, and as a result, users have difficulty distinguishing between used and unused HnB articles. This can be problematic when consumers return used aerosol-generating articles to their original packaging along with other new (unused) aerosol-generating articles, which may occur if there is no nearby trash can for disposing of used / consumed aerosol-generating articles.

[0005] It would be desirable to provide an aerosol-generating article that allows used aerosol-generating articles to be easily distinguished from unused aerosol-generating articles.

[0006] It may be particularly desirable to provide an aerosol-generating article with a front plug and a coated stick wrap, so that a used aerosol-generating article can nevertheless be easily distinguished from an unused aerosol-generating article.

[0007] It would further be desirable to provide an aerosol-generating article that allows a used aerosol-generating article to be distinguished from an unused aerosol-generating article at all times, at least for several days. Summary of the Invention

[0008] According to some embodiments of the present invention, an aerosol-generating article comprises a plurality of elements and a stick wrap configured to connect the rod-shaped elements to form the aerosol-generating article, the aerosol-generating article configured to display a visually perceptible marking upon contact with moisture from the stick wrap.

[0009] As used herein, the term "heated aerosol-generating article" refers to an aerosol-generating article for producing an aerosol that includes an aerosol-generating substrate that is intended to be heated, rather than combusted, to release volatile compounds capable of forming an aerosol. Such articles are commonly referred to as "heat-not-burn" products.

[0010] As used herein, the term "aerosol-generating substrate" refers to a substrate capable of releasing, upon heating, volatile compounds capable of forming an aerosol. The aerosol generated from the aerosol-generating substrate of the aerosol-generating articles described herein may be visible or invisible and may include vapor (e.g., fine particles of a substance in a gaseous state, e.g., of a substance that is normally a liquid or solid at room temperature) and liquid droplets of the gas and condensed vapor.

[0011] As used herein, the term "rod" or "rod-shaped element" refers to a generally cylindrical element of substantially polygonal cross-section, and preferably of circular, oval or elliptical cross-section. As used herein, the term "article" refers to an aerosol-generating article, unless otherwise specified.

[0012] As used herein, the term "longitudinal" refers to a direction corresponding to the major longitudinal axis of the aerosol-generating article extending between the upstream and downstream ends of the aerosol-generating article. During use, air is drawn longitudinally through the aerosol-generating article. The term "transverse" refers to a direction perpendicular to the longitudinal axis.

[0013] As used herein, the terms "upstream" and "downstream" refer to the relative position of an element (or part of an element) of an aerosol-generating article with respect to the direction in which aerosol is transported through the aerosol-generating article during use.

[0014] The aerosol-generating articles according to the present invention are suitable for use in aerosol-generating systems comprising an electrically heated aerosol generator having an internal heating element for heating an aerosol-generating substrate. For example, the aerosol-generating articles according to the present invention find particular application in aerosol-generating systems comprising an electrically heated aerosol generator having an internal heater blade adapted to be inserted into a rod of the aerosol-generating substrate. Aerosol-generating articles of this type are described in the prior art, for example in EP-A-0 822 670.

[0015] As used herein, the term "aerosol-generating device" refers to a device that includes a heating element that interacts with an aerosol-generating substrate of an aerosol-generating article to generate an aerosol.

[0016] As used herein, the term "water-coloring portion" refers to a portion of a wrapper used in an aerosol-generating system that exhibits a visually perceptible response upon contact with moisture. The visually perceptible response of the water-coloring portion may include one or more of a change in color and a change in opacity of the water-coloring portion.

[0017] As described above, the aerosol-generating article is configured to display a visually perceptible marking upon contact with moisture from the stick wrap. As discussed in more detail below, the article may be configured in various ways, including having the ability to display a visually perceptible marking. The aerosol-generating article may be configured to include a permanent marking that is not visually perceptible on an unused aerosol-generating article and becomes visually perceptible upon use of the aerosol-generating article. Alternatively, the unused aerosol-generating article may not include a marking, but a marking may be generated upon use of the aerosol-generating article. In the latter case, the marking may also be displayed so as to appear upon use of the aerosol-generating article.

[0018] By configuring the aerosol-generating article so that a visually perceptible marking is manifested or revealed upon use, a user can easily distinguish between a used and an unused aerosol-generating article.

[0019] This can be particularly advantageous when a consumer returns a used aerosol-generating article to its original packaging and also keeps an unused aerosol-generating article. This situation may arise when there is no trash can available for disposing of the used aerosol-generating article. The aerosol-generating articles described herein allow a user to easily tell the difference between a used and an unused aerosol-generating article, thereby avoiding an unpleasant and potentially harmful user experience.

[0020] Furthermore, because the user can distinguish between used and unused articles, the user may be more inclined to keep the unused aerosol-generating article rather than littering or improperly disposing of the used aerosol-generating article.

[0021] According to embodiments of the present invention, at least a portion of the wrapper of the aerosol-generating article may be configured as a water-coloring portion. According to embodiments of the present invention, at least a portion of the stick wrap of the aerosol-generating article may be configured as a water-coloring portion. A water-coloring portion is a portion that changes its appearance upon contact with moisture. A water-coloring portion may change its color or opacity upon contact with moisture.

[0022] The color or opacity change of the water-colored portion of the stick wrap may be irreversible. The color or opacity change of the water-colored portion of the stick wrap may be irreversible, at least considering the time scale over which a user might reasonably be expected to carry a used aerosol-generating article. To qualify as an irreversible color change, the change must last for at least 10 days, at least 5 days, or at least 3 days. The color or opacity change of the water-colored portion of the stick wrap may last for at least 24 hours.

[0023] The marking on the aerosol-generating article is made clearly visible due to a change in color or opacity of the water-colored portion of the stick wrap. The change in color or opacity of the water-colored portion of the stick wrap may increase the contrast ratio of the marking relative to the surrounding area of ​​the aerosol-generating article. The change in contrast ratio may be at least 0.5 to 30. The change in contrast ratio may be 1 to 20. The change in contrast ratio may be 2 to 15. The change in contrast ratio may be 3 to 10.

[0024] The aerosol-generating article may be configured to be heated during use. By heating the aerosol-generating article, an aerosol may be formed by evaporation of volatile components of an aerosol-forming substrate contained within the aerosol-generating article.

[0025] The aerosol-generating article may have a proximal end and a distal end. The stick-wrap wrapped element may define an internal airflow path from the distal end to the proximal end of the aerosol-generating article. The stick-wrap wrapped element may be rod-shaped. The stick-wrap wrapped element may be cylindrical and have a generally circular cross-section.

[0026] The aerosol-generating article components may include a substrate plug containing a solid aerosol-forming substrate. The aerosol-generating article components may additionally include one or more of a front-end filter, a mouthpiece filter, a PLA filter, a hollow acetate tube, and a cardboard tube.

[0027] One or more of the individual elements from which the aerosol-generating article is formed may comprise plug wrap, which may be a paper wrapper commonly used in the manufacture of aerosol-generating articles.

[0028] The moisture that the water-coloring portion contacts may be moisture generated as the aerosol-generating article heats and the air and generated aerosol subsequently condense during user experience. As described above, the aerosol generated from the aerosol-generating substrate of the aerosol-generating article described herein may include vapor, as well as droplets of gas and condensed vapor. Thus, an increase in moisture indicates the occurrence of a user experience. This increase in moisture is then used in the mechanisms described herein to distinguish used from unused aerosol-generating articles. The use of a stick wrap containing a water-coloring portion is a convenient and inexpensive way to introduce a distinctive feature that allows users to recognize used aerosol-generating articles.

[0029] There are several ways in which the aerosol-generating article can be configured so that a marking is revealed upon contact of the aerosol-generating article with moisture. Preferred methods for providing such markings are disclosed below.

[0030] According to embodiments, the stick wrap may include a water-colored portion covering a portion of the outer surface of the rod-shaped element of the aerosol-generating article. The portion of the outer surface of the rod-shaped element covered by the water-colored portion of the stick wrap may be marked with a permanent marking. The water-colored portion of the stick wrap may be configured to remain opaque unless the aerosol-generating article is unused and has come into contact with increased levels of moisture. The water-colored portion of the stick wrap may further be configured to decrease in opacity upon contact with moisture.

[0031] The stick wrap of such an aerosol-generating article covers the marking before use. Due to the opacity of the water-colored portion of the stick wrap, the regular marking below the water-colored portion of the stick wrap is not visually perceptible by the user. Therefore, such an aerosol-generating article can be easily identified as an unused aerosol-generating article. During user experience, the aerosol-generating article is heated, and the user draws air through the aerosol-generating article, thereby forming an aerosol that cools within the aerosol-generating article before inhalation. As the heated aerosol cools, condensation and a general increase in the humidity level in the airflow path through the aerosol-generating article occurs. The water-colored portion of the stick wrap comes into contact with humidity generated within the aerosol-generating article. Upon contact with this humidity, the water-colored portion of the stick wrap becomes less opaque, and the regular marking below the water-colored portion of the stick wrap becomes visually perceptible by the user from the outside.

[0032] The water-colored portion of the stick wrap can be made from conventional paper used in the manufacture of aerosol-generating articles. When such paper comes into contact with moisture, it can become more transparent than in its dry state. This can be caused by the similarity of the refractive index of water to the cellulose fibers of the paper. As the moisture content increases, the stick wrap becomes wet, and as water droplets occupy the cavities between the cellulose fibers, the overall refractive index of the wet stick wrap becomes more homogeneous. Therefore, light passing through the wet stick wrap experiences less total internal reflection, which increases the transparency of the stick wrap. The stick wrap becomes less opaque, and markings underneath such water-colored portions of the stick wrap become visible. It has been found that this effect does not completely disappear when the stick wrap dries. Therefore, even after the moisture level of the stick wrap returns to ambient conditions, the markings can still be seen compared to an unused aerosol-generating article.

[0033] The water-coloring portion of the stick wrap may be formed from a paper sheet material having a thickness of less than 100 micrometers. The water-coloring portion of the stick wrap may be formed from a paper sheet material having a thickness of less than 65 micrometers, less than 60 micrometers, less than 55 micrometers, less than 50 micrometers, less than 45 micrometers, less than 40 micrometers, or less than 35 micrometers. The thinner the paper material, the more enhanced the effect on the change in opacity of the paper material when wet.

[0034] The paper sheet material on which the water-colorable portion of the stick wrap is formed can have a basis weight of less than 65 grams per square meter, less than 60 grams per square meter, less than 55 grams per square meter, less than 50 grams per square meter, less than 45 grams per square meter, less than 40 grams per square meter, less than 35 grams per square meter, less than 30 grams per square meter, less than 25 grams per square meter, or less than 20 grams per square meter.

[0035] The water-forming portion of the stick wrap may be formed from a paper sheet material having a higher porosity compared to cigarette paper typically used in HnB products. The water-forming portion of the stick wrap may be formed from a paper sheet material having a porosity that leads to increased air permeability. The air permeability of the paper sheet material used in the water-forming portion of the stick wrap may be greater than 30 Coresta Units (CU) at an applied pressure differential of 1 kilopascal (kPa).

[0036] The water-colored portion of the stick wrap may be formed from a paper sheet material that has any color in the dry state, and preferably from a paper sheet material that is white in the dry state.

[0037] Without wishing to be bound by theory, conventional paper materials are generally opaque because the cellulose fiber material forms a porous structure that further includes hollow, air-filled cavities, and the paper material also typically includes mineral fillers located between the cellulose fibers. The mineral fillers are provided in crystalline form. In a dry paper sheet where the mineral fillers are surrounded by air, the large difference in refractive index between the air and the mineral filler causes light to be scattered by these filler materials. Thus, the paper material appears opaque.

[0038] When such paper material comes into contact with moisture, the porous structure becomes filled with water. The water has a different refractive index, which is closer to the refractive index of the paper material and the mineral filler material contained in the paper. This smaller difference in refractive index between the water and the paper material or mineral filler results in less scattering and makes the paper material more translucent.

[0039] Hydrocarbons such as glycerin can contribute to increasing the translucency of paper materials in at least two ways. On the other hand, fatty materials also increase the refractive index. Therefore, for the same reasons as described above, contacting paper materials with glycerin also increases the translucency of the paper material. In addition, the presence of glycerin helps maintain an increased moisture level in the aerosol-forming substrate. This increased moisture level, in turn, enhances aerosol formation and moisture generation during use of the aerosol-generating system. Therefore, hydrocarbon materials such as glycerin directly and indirectly enhance the effects of the present invention.

[0040] To prevent moisture from the outside air from triggering the transparency of the stick wrap, the stick wrap may have an outer layer or coating extending over at least the water-coloring portion of the stick wrap. The coating may be hydrophobic and transparent. The coating may prevent contact of the coated area of ​​the stick wrap with ambient moisture.

[0041] According to embodiments, the stick wrap may be configured to be substantially transparent. The stick wrap may further be configured to have a water-colored portion. The water-colored portion may be configured to be opaque in a dry state and to decrease in opacity upon contact with moisture. Again, upon contact with moisture, the water-colored portion decreases in opacity, allowing markings on the exterior surface of the element located underneath the water-colored portion to be visible.

[0042] The water-coloring portion of the stick wrap may also be configured to change color upon contact with moisture, which may be perceived by the user and used as an indication or marking of the aerosol generating device that has been used.

[0043] For example, a stick wrap may be provided with a water-colored portion formed by applying a stripe of water-colored ink onto the outer surface of the stick wrap. Such water-colored ink may have a yellowish color in a dry state. Upon contact with moisture, the water-colored ink may change its color, for example, to blue. To make the water-colored portion invisible when the stick has not yet been used, the color of the remainder of the stick wrap may be configured to be approximately the same color as the water-colored ink in a dry state. Thus, prior to use, the complete stick wrap has a homogenous yellowish appearance, with no visible markings. Upon contact with moisture, the water-colored portion changes its color to blue, indicating contact with moisture and, in turn, consumption in the user experience.

[0044] The stick wrap may be substantially transparent and may have a water-coloring portion configured to be opaque when unused or in a dry state. The water-coloring portion may be further configured to change transparency upon contact with moisture. Again, the aerosol-generating article is configured to exhibit a permanent marking on the outer surface of the element covered by the water-coloring portion of the stick wrap. When the water-coloring portion of the stick wrap comes into contact with moisture, the water-coloring portion becomes transparent, revealing the marking underneath. Again, the marking is visible after use, allowing the user to distinguish between used and unused aerosol-generating articles.

[0045] In a further embodiment, the aerosol-generating article includes a color pigment that is transported to the outer surface of the stick wrap by moisture in the stick wrap and capillary action. Upon contact of moisture carrying the color pigment with the stick wrap, a marking indicating that the aerosol-generating article has been used appears on the stick wrap. The color pigment is preferably provided within an element of the aerosol-generating article. The color pigment may be provided within a plug wrap used to package the element of the aerosol-generating article. Moisture generated within the interior volume of the aerosol-generating article, traveling radially outward through the plug wrap, and further into the stick wrap may carry the color pigment to the stick wrap and generate a marking on the stick wrap that is visually perceptible by a user.

[0046] The stick wrap can be configured to have a higher capillary action than the plug wrap used in the aerosol-generating article. Using a stick wrap with a higher capillary action helps combat the effects caused by ambient moisture. Because of its higher capillary action, any ambient moisture that enters the stick wrap from the outside remains within the stick wrap and does not come into contact with the color pigment. Only moisture generated internally within the aerosol-generating article can migrate through the plug wrap and carry the color pigment toward the outer surface of the stick wrap. Therefore, by using a stick wrap with a higher capillary action, an outer coating that protects the stick wrap from ambient moisture can be dispensed. The protective effect of the higher capillary action of the stick wrap depends on the difference in capillary action used in the wrapper material. The greater this difference, the better the protective effect. Therefore, using a stick wrap with a higher capillary action can help reduce spontaneous migration of the color pigment provided within the aerosol-generating article.

[0047] The markings on the aerosol-generating element may have any suitable form that can be easily perceived and understood by a user. The markings may include words, graphical elements, or symbols that may be useful for conveying information to a user. The markings may be printed markings. The markings may include "In Use," "Empty," "Discard," or similar terms. The symbols may include an "X" (initial X), an "!" (exclamation point), a caution sign, or any other symbol suitable for alerting or warning a user.

[0048] The marking may further be configured to indicate the amount of moisture received within the marking zone. The amount of moisture relative to the consumption level of the aerosol-generating article may be converted into the size of the marking area. The amount of moisture may be converted into the amount of marking that appears. For example, the marking may be provided in the form of a gradual marking. The larger the marking, or the greater the percentage of the marking that is exposed to moisture, the higher the level of exposure to moisture and the higher the consumption level. Therefore, the progression of the color change may be used to indicate to the user how much the aerosol-generating article has been used. The area reached by moisture may be controlled according to the amount of moisture by using paper treatments, thereby allowing for moisture changes. While such treatments may be available for water-coloring inks, this is not easily achievable using thermochromic inks. Thermochromic inks are typically sensitive to the value of the maximum temperature reached, but not to the amount of heat involved. Therefore, since the maximum temperature has already been reached during the first user experience, an aerosol-generating article having a thermochromic ink indicator will show the same indication for a completely consumed aerosol-generating article as it would for an aerosol-generating article that has been heated for only one puff.

[0049] The area where the marking appears can be any specific part of the aerosol-generating article. The area can be provided so that it is easily recognizable by the user when removing the aerosol-generating article from the package or when introducing the aerosol-generating article into an aerosol-generating device. The marking is preferably located in a position that remains visible when the aerosol-generating article has already been inserted into the aerosol-generating device. In this way, the user still has an opportunity to detect when they are about to reuse a depleted aerosol-generating article.

[0050] The marking may be provided at a longitudinal location downstream of a substrate plug containing the aerosol-forming substrate, and since the primary heating occurs in the substrate plug, condensation occurs primarily on elements of the aerosol-generating article located downstream of the substrate plug.

[0051] To facilitate radial moisture migration toward the stick wrap, one or more of the elements of the aerosol-generating article may include small openings or perforations extending generally radially. For example, a cardboard tube located downstream of the substrate plug may include a small opening in the cardboard tube below the plug wrap so that a small portion of the heated air and aerosol generated within the cardboard tube can reach the stick wrap.

[0052] The areas of the aerosol-generating article that can be reached by moisture may vary and may therefore depend on the type of heating system of the aerosol-generating device in which the aerosol-generating article is used.

[0053] In the case of an internal heater, such as an induction-heated susceptor, provided longitudinally at the center of the plug of the aerosol-forming substrate, the primary heat is generated at the center of the plug. Moisture, caused by condensation of the heated air and aerosol, is generated primarily in the cooler peripheral regions of the substrate and the plug wrap. From there, the moisture spreads by capillary action in the plug wrap and migrates toward the stick wrap.

[0054] In the case of an external heater, heat is generated primarily in the peripheral region of the substrate plug. The temperature around and near the substrate plug would likely be too high to allow moisture to reach the substrate plug wrap. However, moisture caused by condensation of heated air and aerosols may occur in elements located downstream of the substrate plug. In such an embodiment, dedicated small air channels may be used that travel from the inner core of one of the downstream elements to the plug wrap. Moisture may then travel radially along these channels to reach the stick wrap.

[0055] In this case, the marking must be provided on a portion of the stick wrap separate from the substrate plug. Providing the marking separate from the substrate plug may be desirable in any event, as such positioning limits the possibility that the materials comprising the marking or the hydrophobic coating may form harmful and potentially harmful components during heating.

[0056] As described above, an aerosol-generating article may include multiple elements. Each of these elements may be surrounded by plug wrap. The elements themselves or the plug wrap material may have undergone specific treatments before being combined into the aerosol-generating article. Such treatments may aim to control various moisture-related properties of the elements. Such treatments may adjust the water resistance properties, water absorption, or moisture tension level of the elements, such as to expel and / or control moisture in the aerosol-generating article.

[0057] In particular, the individual plug wraps or elements can be configured to have a fairly low porosity or can be configured to be highly hydrophobic, thereby ensuring that as much moisture as possible generated with condensation of the aerosol during the user experience is available for migration to the stick wrap containing the water-coloring moiety.

[0058] Furthermore, the advantageous stick structure can also help enhance moisture transfer toward the stick wrap. For example, during construction of the aerosol-generating article, a small void can form between the outer surface of the plug wrap and the inner surface of the stick wrap of the packaged element. In a dry state, the plug wrap and the stick wrap are not in direct contact. This aspect contributes to increasing the opacity of the stick wrap, thereby making any underlying markings less visible. During the user experience when moisture is generated, this moisture can also fill the void between the wrappers. This layer of moisture can replace the void previously present between the two wrappers, creating a kind of "bridge" and establishing direct contact between the wrappers. This effect also enhances the visibility of the underlying marking during and after use of the aerosol-generating system.

[0059] As mentioned above, it may be advantageous to form the stick wrap from a paper material having a somewhat lower thickness and reduced basis weight. However, using such a material may reduce the strength of the packaged structure. To compensate for the reduced thickness and low basis weight of the stick wrap, one or more of the plug wraps, particularly the aerosol-forming material plug wrap, may be formed from a thicker and higher basis weight material.

[0060] To further control the transport and distribution of moisture within the aerosol-generating article, the aerosol-generating article may include an increased capillary element, which may transport moisture to a dedicated portion of the aerosol-generating article. The increased capillary element may be used to transport moisture toward the portion of the aerosol-generating article that includes the marking. The increased capillary element may be a longitudinal element. The increased capillary element may be a strip, thread, yarn, wick, or any other suitable capillary element.

[0061] The capillary element may extend parallel to the longitudinal axis of the aerosol-generating article and may help to distribute moisture evenly along the entire length of the aerosol-generating article.

[0062] The capillary element may be coated with a hydrophobic material. By coating the capillary element with a hydrophobic material, the capillary element effectively forms an element that acts like a tube. Moisture can enter at one end of the capillary element and be transported through the capillary of the element toward the other end. Because the length of the capillary material is coated with a hydrophobic material, moisture may not enter the capillary element through the hydrophobic coating, or may enter only in a reduced amount. Such elements may be particularly useful for use in combination with capsule-holding color pigments. Moisture entrained with the color pigment can be guided along the capillary element toward a predetermined portion of the stick wrap. At the output end of the capillary element, the moisture carrying the color pigment is released onto the stick wrap, thereby forming a visually perceptible marking on the outer surface of the stick wrap.

[0063] The heated aerosol-generating article may comprise multiple elements including a rod of aerosol-generating substrate.

[0064] The aerosol-generating article may generally comprise a hollow acetate tube directly adjacent to an aerosol-generating substrate, the rod of which is formed of aerosol-forming material, which may comprise homogenized tobacco material.

[0065] As used herein, the term "homogenized tobacco material" encompasses any tobacco material formed by agglomeration of particles of tobacco material. A sheet or web of homogenized tobacco material is formed by agglomerating particulate tobacco obtained by grinding or otherwise pulverizing one or both of tobacco lamina and tobacco stems. In addition, homogenized tobacco material may contain one or more small amounts of tobacco dust, tobacco fines, and other particulate tobacco by-products formed during tobacco processing, handling, and shipping. Sheets of homogenized tobacco material may be produced by molding, extrusion, papermaking processes, or any other suitable process known in the art.

[0066] In a preferred embodiment, the rod comprises one or more sheets of homogenized tobacco material gathered together and surrounded by an outer wrapper to form a plug. As used herein with respect to the present invention, the term "sheet" refers to a laminar element having a width and length that are significantly greater than its thickness. As used herein with respect to the present invention, the term "assembly" refers to a sheet that is coiled, folded, or otherwise compressed or contracted in a direction substantially transverse to the longitudinal axis of the aerosol-generating article.

[0067] The sheets of homogenized tobacco material used in the present invention may have a tobacco content of at least about 40 weight percent on a dry weight basis, more preferably at least about 50 weight percent on a dry weight basis, more preferably at least about 70 weight percent on a dry weight basis, and most preferably at least about 90 weight percent on a dry weight basis.

[0068] Preferably, the sheet of homogenized tobacco material includes an aerosol former. The sheet of homogenized tobacco material may include a single aerosol former. Alternatively, the sheet of homogenized tobacco material may include a combination of two or more aerosol formers.

[0069] Suitable aerosol formers are well known in the art and include, but are not limited to, monohydric alcohols (such as menthol), polyhydric alcohols (such as triethylene glycol, 1,3-butanediol, and glycerin), esters of polyhydric alcohols (such as glycerol monoacetate, glycerol diacetate, or glycerol triacetate), and aliphatic esters of monocarboxylic, dicarboxylic, or polycarboxylic acids (such as dimethyl dodecanedioate, dimethyl tetradecanedioate, erythritol, 1,3-butylene glycol, tetraethylene glycol, triethyl citrate, propylene carbonate, ethyl laurate, triacetin, meso-erythritol, diacetin mixtures, diethyl suberate, triethyl citrate, benzyl benzoate, benzyl phenylacetate, ethyl vanillate, tributyrin, lauryl acetate, lauric acid, myristic acid, and propylene glycol).

[0070] Preferably, the sheet of homogenized tobacco material has an aerosol former content of greater than 5 percent on a dry weight basis. The sheet of homogenized tobacco material may have an aerosol former content of approximately 5 percent to approximately 30 percent on a dry weight basis. In one preferred embodiment, the sheet of homogenized tobacco material has an aerosol former content of approximately 20 percent on a dry weight basis.

[0071] The sheets of homogenized tobacco material used in the present invention may include one or more intrinsic binders that are tobacco intrinsic binders, one or more extrinsic binders that are tobacco extrinsic binders, or a combination thereof, to aid in the aggregation of the particulate tobacco. Alternatively, or in addition, the sheets of homogenized tobacco material used in the aerosol-generating substrate may include other additives, including, but not limited to, tobacco and non-tobacco fibers, aerosol formers, humectants, plasticizers, flavorants, fillers, aqueous and non-aqueous solvents, and combinations thereof.

[0072] Suitable extrinsic binders for inclusion in the sheets of homogenized tobacco material used in the present invention are well known in the art and include, but are not limited to, gums such as guar gum, xanthan gum, gum arabic, locust bean gum, and the like; cellulosic binders such as hydroxypropyl cellulose, carboxymethyl cellulose, hydroxyethyl cellulose, methyl cellulose, ethyl cellulose, and the like; polysaccharides such as starch, organic acids (such as alginic acid), conjugate base salts of organic acids (such as sodium alginate), agar, pectin, and the like; and combinations thereof.

[0073] Suitable non-tobacco fibers for inclusion in sheets of homogenized tobacco material for use in aerosol-generating substrates are well known in the art and include, but are not limited to, cellulose fibers, softwood fibers, hardwood fibers, jute fibers, and combinations thereof. Prior to inclusion in sheets of homogenized tobacco material for use in aerosol-generating substrates, the non-tobacco fibers may be processed by any suitable process known in the art, including, but not limited to, mechanical pulping, refining, chemical pulping, bleaching, sulfate pulping, and combinations thereof.

[0074] The homogenized tobacco sheet used in the present invention preferably has a width of about 70 mm to about 250 mm, for example, about 120 mm to about 160 mm. The thickness of the homogenized tobacco material sheet is preferably about 50 micrometers to about 300 micrometers, and more preferably about 150 micrometers to about 250 micrometers.

[0075] The homogenized tobacco sheets used in the aerosol-generating articles of the present invention may be made by methods well known in the art (for example, the methods disclosed in International Patent Application No. WO-A-2012 / 164009A2).

[0076] In one preferred embodiment, a sheet of homogenized tobacco material for use in an aerosol-generating article is formed from a slurry containing particulate tobacco, guar gum, cellulose fibers, and glycerin by a molding process.

[0077] As an alternative to using an aggregate sheet of homogenized tobacco material as described above, the aerosol-generating substrate may be formed from a plurality of strips or pieces of homogenized tobacco material. For example, the aerosol-generating substrate may be formed from a plurality of pieces of homogenized tobacco material that are longitudinally aligned, grouped together, and wrapped to form a rod of aerosol-generating substrate.

[0078] The homogenized tobacco material pieces preferably have a length of about 10 millimeters to about 20 millimeters, more preferably about 12 millimeters to about 18 millimeters, more preferably about 14 millimeters to about 16 millimeters, and even more preferably about 15 millimeters. Alternatively, or additionally, the homogenized tobacco material pieces preferably have a width of about 0.4 millimeters to about 0.8 millimeters.

[0079] The density of the homogenized tobacco material sheet from which the fragments are formed is preferably about 500 to about 1500 milligrams per cubic centimeter, more preferably about 800 to about 1200 milligrams per cubic centimeter, even more preferably about 900 to about 1100 milligrams per cubic centimeter, and most preferably about 900 to about 970 milligrams per cubic centimeter.

[0080] The bulk density of the homogenized tobacco material fragments within the aerosol-generating substrate is preferably from about 0.4 grams per cubic centimeter to about 0.8 grams per cubic centimeter, more preferably from about 0.5 grams per cubic centimeter to about 0.7 grams per cubic centimeter, and most preferably from about 0.65 grams per cubic centimeter to about 0.67 grams per cubic centimeter.

[0081] As noted above, the homogenized tobacco material may be formed by forming a slurry. Alternatively, the homogenized tobacco material may be formed by another suitable method, such as, for example, an extrusion method.

[0082] The aerosol-generating substrate preferably comprises a rod of homogenized tobacco material surrounded by a wrapper, the wrapper being provided around and in contact with the homogenized tobacco material. The wrapper may be formed from any suitable sheet material capable of being wrapped around the homogenized tobacco material to form an aerosol-forming substrate. The wrapper may be porous or non-porous. Preferably, the wrapper is a paper wrapper, although alternatively, the wrapper may be other than paper.

[0083] The rod of aerosol-forming substrate preferably has an outer diameter approximately equal to the outer diameter of the aerosol-generating article.

[0084] The aerosol-generating substrate rod preferably has an outer diameter of at least 5 millimeters. The aerosol-generating substrate rod may have an outer diameter of about 5 millimeters to about 12 millimeters, for example, about 5 millimeters to about 10 millimeters, or about 6 millimeters to about 8 millimeters. In one preferred embodiment, the aerosol-generating substrate rod has an outer diameter of 7.2 millimeters ±10 percent.

[0085] The rod of the aerosol-generating substrate may have a length of about 7 mm to about 15 mm. In one embodiment, the rod of the aerosol-generating substrate may have a length of about 10 mm. In a preferred embodiment, the rod of the aerosol-forming substrate has a length of about 12 mm.

[0086] Preferably, the rod of aerosol-generating substrate has a substantially uniform cross section along the length of the rod, and it is particularly preferred that the rod of aerosol-generating substrate has a substantially circular cross section.

[0087] Preferably, the aerosol-generating article according to the present invention comprises one or more elements in addition to the rod of aerosol-forming substrate. For example, the aerosol-generating article may further comprise at least one of a mouthpiece, an aerosol cooling element, and a support element (such as a hollow acetate tube). For example, in one preferred embodiment, the aerosol-generating article comprises, in a linear, continuous arrangement, a rod of aerosol-generating substrate as described above, a support element located immediately downstream of the aerosol-forming substrate, an aerosol cooling element located downstream of the support element, and a stick wrap surrounding the rod, support element, and aerosol cooling element.

[0088] An aerosol-generating system according to the present invention comprises an aerosol-generating article as described in detail above in combination with an aerosol-generating device adapted to receive the upstream end of the aerosol-generating article during user experience. The aerosol-generating device comprises a heating element configured to heat the aerosol-generating substrate in use to generate an aerosol. The heating element is preferably adapted to penetrate the aerosol-generating substrate when the aerosol-generating article is inserted into the aerosol-generating device. For example, the heating element is preferably in the form of a heater blade.

[0089] The heater element may also be an external heating element that surrounds the aerosol-generating article during use.

[0090] The heating element may be a resistive heating element or an inductive heating element.

[0091] The heating element is controlled to operate within a predetermined operating temperature range during use, below a maximum operating temperature. The thermal indicator of the aerosol-generating article is adapted to not reach a threshold temperature during normal use of the aerosol-generating article in an aerosol-generating device in which the heating element operates below the maximum operating temperature. This ensures that the thermal indicator will not be activated during normal use when the aerosol-generating article and aerosol-generating device are used together.

[0092] Preferably, the aerosol generating device additionally comprises a housing, a power supply connected to the heating element, and a control element configured to control the supply of power from the power supply to the heating element.

[0093] A suitable aerosol generating device for use in the aerosol generating system of the present invention is described in WO 2013 / 098405.

[0094] The present invention also relates to a method of manufacturing an aerosol-generating article, comprising providing a plurality of elements and providing a stick wrap. The method further comprises connecting the elements by wrapping the stick wrap around the elements to form an aerosol-generating article. The aerosol-generating article is configured to exhibit a visually perceptible marking upon contact with moisture from the stick wrap. [Example]

[0095] Below is provided a non-exhaustive list of non-limiting examples, any one or more of the features of these examples may be combined with any one or more features of any other example, embodiment, or aspect described herein.

[0096] Example 1: An aerosol-generating article, comprising: Multiple elements and a stick wrap configured to connect the elements to form the aerosol-generating article; The aerosol-generating article is further configured to exhibit a visually perceptible marking upon contact with moisture from the stick wrap. Example 2: 10. The aerosol-generating article of claim 1, wherein the aerosol-generating article is configured to be heated such that an aerosol is formed by evaporation of a volatile component of the aerosol-forming substrate. Example 3: An aerosol-generating article described in any one of Examples 1 or 2, wherein the aerosol-generating article has a proximal end and a distal end, and the rod-shaped element defines an internal airflow path from the distal end to the proximal end of the aerosol-generating article. Example 4: 4. The aerosol-generating article of any one of Examples 1 to 3, wherein the element comprises a substrate plug comprising the aerosol-forming substrate. Example 5: The aerosol-generating article of any one of Examples 1 to 4, wherein the substrate plug comprises glycerin. Example 6: 6. An aerosol-generating article according to any one of Examples 1 to 5, wherein the rod-shaped element comprises one or more of a front-end filter, a mouthpiece filter, a hollow acetate tube, and a cardboard tube. Example 7: An aerosol-generating article according to any one of Examples 1 to 6, wherein one or more of the components comprises a plug wrap. Example 8: An aerosol-generating article according to any one of Examples 1 to 7, wherein at least a portion of the stick wrap is configured as a water-colorable portion that changes color or opacity upon contact with moisture. Example 9: An aerosol-generating article as described in any one of Examples 1 to 8, wherein the water-colorable portion of the stick wrap covers a portion of the outer surface of the element, the portion of the outer surface of the element is marked, and the water-colorable portion of the stick wrap is configured to become less opaque upon contact with moisture. Example 10: An aerosol-generating article described in any one of Examples 8 or 9, wherein the stick wrap is substantially transparent, the stick wrap has a water-colored portion that is opaque in a dry state, and the water-colored portion becomes less opaque upon contact with moisture. Example 11: 9. An aerosol-generating article according to any one of Examples 1 to 8, wherein the water-coloring portion of the stick wrap is configured to change color upon contact with moisture. Example 12: An aerosol-generating article as described in Example 11, wherein the water-coloring portion of the stick wrap is configured to have the same or similar color as the stick wrap before contact with moisture, and the water-coloring portion of the stick wrap is further configured to change its color upon contact with moisture. Example 13: 13. The aerosol-generating article of any one of Examples 1 to 12, wherein the aerosol-generating article comprises a color pigment that is transported to the outer surface of the stick wrap by moisture in the stick wrap and capillary action. Example 14: An aerosol-generating article according to any one of Examples 1 to 13, wherein the moisture generated by the condensation of the heated air or aerosol contacts the water-coloring portion of the stick wrap. Example 15: An aerosol-generating article according to any one of Examples 1 to 14, wherein the plug wrap and stick wrap are made from paper materials having different thicknesses or different basis weights. Example 16: An aerosol-generating article according to any one of Examples 1 to 15, wherein the marking comprises words, graphical elements, or symbols useful for conveying information to a user. Example 17: 17. The aerosol-generating article of example 16, wherein the marking is configured to indicate the amount of moisture received within the marking zone. Example 18: 18. An aerosol-generating article according to any one of Examples 1 to 17, wherein the marking is provided at a longitudinal position downstream of the substrate plug comprising the aerosol-forming substrate. Example 19: An aerosol-generating article according to any one of Examples 1 to 18, wherein the aerosol-generating article comprises an element with increased capillary action for transporting moisture to a dedicated portion of the aerosol-generating article. Example 20: An aerosol-generating article as described in Example 19, wherein the aerosol-generating article comprises an element with increased capillary action for transporting moisture toward a portion of the aerosol-generating article that includes the marking. Example 21: 21. The aerosol-generating article of Example 20, wherein the element exhibiting increased capillary action is a twisted yarn. Example 22: 22. An aerosol-generating article as described in Example 21, wherein the thread is coated with a hydrophobic material such that moisture from one end of the thread is advantageously transported to the other end of the thread in contact with the stick wrap. Example 23: An aerosol-generating article described in any of Examples 1 to 22, wherein one or more of the rod-shaped elements may include perforations or openings to enhance the radial movement of moisture from the airflow channel toward the stick wrap. Example 24: An aerosol-generating article according to any one of Examples 1 to 23, wherein the stick wrap is covered by a hydrophobic layer. Example 25: An aerosol-generating article according to any one of Examples 1 to 24, wherein the change in color or opacity of the water-coloring portion is irreversible. Example 26: an aerosol generator; An aerosol-generating system comprising the aerosol-generating article according to any one of Examples 1 to 25. Example 27: 1. A method for producing an aerosol-generating article, comprising: providing a plurality of rod-shaped elements; Providing stick wraps; and connecting the rod-shaped elements by wrapping the stick wrap around the rod-shaped elements to form an aerosol-generating article; The method, wherein the aerosol-generating article is configured to manifest a visually perceptible marking upon contact with moisture from the stick wrap.

[0097] Features described with respect to one embodiment may be equally applied to other embodiments of the invention. [Brief explanation of the drawings]

[0098] The invention will now be further described, by way of example only, with reference to the accompanying drawings in which:

[0099] [Figure 1] FIG. 1 shows a schematic diagram of an aerosol-generating article. [Figure 2] FIG. 2 shows a schematic diagram of the structure of an aerosol-generating article. [Figure 3] FIG. 3 shows details of an inductively heated aerosol-generating article comprising a stick wrap having a water-coloring portion. [Figure 4] FIG. 4 shows an aerosol-generating article having a covered marking and a revealed marking. [Figure 5] FIG. 5 shows a further mechanism for revealing markings on an aerosol-generating article. [Figure 6] FIG. 6 illustrates one embodiment of an aerosol-generating article comprising a clear stick wrap. [Figure 7] FIG. 7 shows an aerosol-generating article containing a colored pigment. [Figure 8] FIG. 8 illustrates various features of markings provided on an aerosol-generating article. [Figure 9] FIG. 9 shows an aerosol-generating article comprising a capillary thread. DETAILED DESCRIPTION OF THE INVENTION

[0100] 1 shows a schematic diagram of a conventional aerosol-generating article 10. The aerosol-generating article 10 is a rod-shaped article comprising multiple rod-shaped elements 12, 14, 16, 18 connected to one another by stick-wrap 30. The stick-wrap 30 is made from conventional cigarette paper. The aerosol-generating article 10 comprises four elements: a front plug 12, a sensory media plug 14 containing an aerosol-forming substrate 15, a hollow acetate tube 16, and a mouthpiece filter 18.

[0101] Each of the elements is separately wrapped in a wrapping material (not shown), also known as a plug wrap, to hold the materials of each element together. These wrapped elements are then wrapped together with a stick wrap 30 to form the stick structure of the aerosol-generating article 10, as shown in FIG.

[0102] Outside air 22 drawn into the aerosol-generating article 10 by the user enters primarily through the front plug 12 at the distal or upstream end 24 of the aerosol-generating article 10. The outside air 22 is directed through the aerosol-forming substrate 15, where it mixes with vapor and other volatile materials produced upon heating of the aerosol-forming substrate 15 to form an aerosol 26. The heated air and aerosol 26 are then directed forward through further elements of the aerosol-generating article 10, exiting the aerosol-generating article 10 at the proximal or downstream end 28 through the mouthpiece filter 18. All of the elements form an internal airflow path 29 through the aerosol-generating article 10.

[0103] FIG. 2 shows an aerosol-generating article 10 comprising three elements 12, 14, and 16, each wrapped in a plug wrap 32, 34, and 36. During manufacture of the aerosol-generating article 10, the individual elements 12, 14, and 16 are aligned and abutted against one another, as indicated by the two arrows at either end of the aerosol-generating article 10. The elements 12, 14, and 16 are then wrapped in an outer wrapping material, a stick wrap 32. Generally, there may be several stick wraps that can overlap one another. For example, tipping paper typically refers to a stick wrap that covers a mouthpiece filter and connects the mouthpiece filter to the rest of the aerosol-generating article 10. This connection can be achieved by overlapping a portion of another stick wrap, a so-called cigarette wrapper, that connects other components of the aerosol-generating article 10. The aerosol-generating article of the present invention is essentially manufactured with corresponding elements as illustrated in the diagrams of FIGS. 1 and 2.

[0104] 3 shows a schematic diagram of an aerosol-generating article 10 according to the present invention. The aerosol-generating article 10 also comprises four rod-shaped elements: a front plug 12, a sensory media plug 14 containing an aerosol-forming substrate 15, a hollow acetate tube 16, and a mouthpiece filter 18. Each of these elements is individually packaged within plug wraps 32, 34, 36, 38.

[0105] The front plug 12, sensory media plug 14, and hollow acetate tube 16 are wrapped together using a first stick wrap 30 to form the front portion of the aerosol-generating article 10. The mouthpiece filter 18 is attached to this front portion by a second stick wrap, commonly referred to as tipping paper 52.

[0106] The sensate plug 14 includes a susceptor element 40 that is used to inductively heat the aerosol-forming substrate 15. Ambient air 22 enters the aerosol-generating article 10 through the front plug 12 at the upstream end 24 of the aerosol-generating article 10. The outside air 22 is heated and, as it is directed through the sensate plug 14, entrains volatilized flavor.

[0107] The heated air and aerosol 26 flow primarily along the longitudinal axis of the aerosol-generating article 10, but a portion 44 flows radially to the outer periphery of the sensory media plug 14, as indicated by arrows 44. At the periphery of the sensory media plug 14, the heated air and aerosol 26 become cooler and condense, thereby forming moisture 46. This moisture 46 migrates by capillary action through the sensory media plug wrap 34 and reaches the inner surface of the stick wrap 30.

[0108] In the embodiment shown in Figure 3, the stick wrap 30 has a water-colored portion 50. The water-colored portion 50 is a portion of the stick wrap 30 that is printed with water-colored ink. In a dry state, the water-colored ink has a color that corresponds to the color of the remainder of the stick wrap 30. Thus, in a dry state, the water-colored portion 50 is not optically perceptible by a user.

[0109] Upon contact with moisture 46 generated during user experience, the water-colored ink in water-colored portion 50 irreversibly changes color from the initial paper-like color to blue, which represents a clear contrast to the initial paper color. Thus, a user can easily perceive water-colored portion 50 after use. Thus, water-colored portion 50 forms a visually perceptible marking that allows a user to easily distinguish a used aerosol-generating article 10 from an unused aerosol-generating article 10.

[0110] The exterior of the stick wrap 30 is provided with a clear hydrophobic coating 54 that extends over the entire surface of the stick wrap 30. The clear hydrophobic coating 54 protects the stick wrap 30 from ambient moisture.

[0111] FIG. 4 shows a further embodiment of an aerosol-generating article comprising a stick wrap having a water-coloring portion 50. In FIG. 4, only the region of the aerosol-generating article 10 containing the water-coloring portion 50 and the marking 60 is shown. The left view of FIG. 4 shows an unused aerosol-generating article 10, while the right view of FIG. 4 shows the same aerosol-generating article 10 after use. The aerosol-generating article 10 comprises an element 16, in this case a PLA filter element. The filter element 16 is wrapped by a plug wrap 36. The outer surface of the plug wrap 36 is provided with a marking 60. The marking 60 is provided in the form of a colored stripe. The plug wrap is further wrapped with a stick wrap 30, which is used to connect the element 16 to an adjacent element of the aerosol-generating article 10. In FIG. 4, the inner surface 30a and outer surface 30b of the stick wrap 30 are shown.

[0112] In FIG. 4 , at least the depicted portion of the stick wrap 30 of the aerosol-generating article 10 is made from conventional cigarette paper. This cigarette paper is opaque in a dry state, but becomes less opaque when exposed to moisture 46. Thus, the depicted portion of the stick wrap forms a water-colored portion 50 within the meaning of the present invention. Prior to use, the depicted portion of the stick wrap 30 is opaque, and a user cannot discern the conventional marking 60 provided on the plug wrap 36 beneath the stick wrap 30. As the aerosol-generating article 10 is used, moisture 46 is generated within the interior volume of the aerosol-generating article 10. Some of this moisture 46 migrates toward the stick wrap 30, thereby increasing the moisture level of the stick wrap 30. After use of the aerosol-generating article 10, the depicted portion of the stick wrap 30 covering the marking 60 is exposed to moisture 46 and becomes less opaque. Thus, a user can visually perceive the marking 60 beneath the stick wrap 30 after use of the aerosol-generating article 10, as shown in the right diagram of FIG. 4 .

[0113] Figure 5 shows a further embodiment of an aerosol-generating article comprising a stick wrap having a water-colored portion 50. Like Figure 4, Figure 5 shows only the region of the aerosol-generating article 10 that includes the water-colored portion 50 and the marking 60. The left view of Figure 5 shows an unused aerosol-generating article 10, while the right view of Figure 5 shows the same aerosol-generating article 10 after use. The structure of the aerosol-generating article 10 is nearly identical to the structure of the aerosol-generating article 10 shown in Figure 4. However, in Figure 5, the stick wrap is now provided with a stripe of water-colored ink that forms the water-colored portion 50.

[0114] The color of the striped water-colored portion 50 is selected to be more or less the same as the color of the stick wrap. Thus, in an unused aerosol-generating article 10, the water-colored portion 50 on the stick wrap 30 is not visually perceptible by the user. Instead, the outer surface of the aerosol-generating article appears to have a uniform color.

[0115] As the aerosol-generating article 10 is used, moisture 46 is generated within the interior volume of the aerosol-generating article 10. Some of this moisture migrates toward the stick wrap 30, thereby increasing the moisture level of the stick wrap 30 and the water-colored portion 50 printed thereon. Upon interacting with this moisture 46, the water-colored ink changes color to form a distinct contrast with the color of the remainder of the stick wrap. In the example of FIG. 5, the water-colored portion turns blue upon contact with moisture 46. A user can now visually perceive the marking 60 on the stick wrap 30 again after use of the aerosol-generating article 10. The stick wrap 30 may be provided with a hydrophobic and transparent outer coating to protect against moisture from the outside air and trigger the color change in the water-colored portion 50.

[0116] Figure 6 shows a further embodiment of an aerosol-generating article comprising a stick wrap having a water-coloring portion 50. Again, the left view of Figure 6 shows an unused aerosol-generating article 10, and the right view of Figure 6 shows the same aerosol-generating article 10 after use. The structure of the aerosol-generating article 10 is substantially identical to the structure of the aerosol-generating article 10 shown in Figure 4. Again, the outer surface of the plug wrap 36 is provided with markings 60 in the form of colored stripes. The plug wrap is further wrapped with a stick wrap 30, which is used to connect element 16 to adjacent elements of the aerosol-generating article 10. In Figure 6, the stick wrap 30 is substantially transparent.

[0117] Stick wrap 30 includes a water-colorable portion 50 that is opaque unless it comes into contact with moisture. Water-colorable portion 50 is provided on the interior surface of stick wrap 30 and completely covers marking 60 on plug wrap 36. Thus, as shown in the left diagram of Figure 6, in a dry state, opaque water-colorable portion 50 covers marking 60 such that marking 60 is not visually perceptible by a user.

[0118] As the aerosol-generating article 10 is used, moisture 46 is generated within the interior volume of the aerosol-generating article 10. Some of this moisture migrates toward the stickwrap 30, thereby increasing the moisture level within the stickwrap 30 and within the water-colored portion 50 printed on its interior surface. Upon interacting with this moisture 46, the water-colored ink changes its opacity and becomes transparent. Due to the change in opacity of the water-colored portion 50, the marking below the water-colored portion 50 becomes apparent. Therefore, the user can again visually perceive the marking 60 through the stickwrap 30 after using the aerosol-generating article 10. To protect against moisture from the outside air and trigger the color change in the water-colored portion 50, the stickwrap 30 may be provided with a hydrophobic and transparent outer coating.

[0119] FIG. 7 illustrates a further embodiment of an aerosol-generating article comprising a stick wrap having a water-coloring portion 50. The left view of FIG. 7 illustrates an unused aerosol-generating article 10, while the right view of FIG. 7 illustrates the same aerosol-generating article 10 after use. The structure of the aerosol-generating article 10 is substantially identical to the structure of the aerosol-generating article 10 illustrated in FIG. 4. Furthermore, FIG. 5 illustrates a color pigment 62 provided between the element 16 and the stick wrap 30. The color pigment is not mobile within an unused aerosol-generating article 10. The color pigment 62 is covered by the opaque stick wrap 30 so that the color pigment 62 is not visible in an unused article. At least the water-coloring portion 50 of the stick wrap 30 exhibits increased capillary action. The term "increased capillary action" means that the capillary action is greater than that of the plug wrap 36.

[0120] As the aerosol-generating article 10 is used, moisture 46 is generated within the interior volume of the aerosol-generating article 10. Some of this moisture migrates radially through the plug wrap 36 toward the stick wrap 30. The color pigment 62 is carried toward the outer surface of the stick wrap 30 by the internal moisture 46 and increased capillary action of the stick wrap 30. On the outer surface of the stick wrap, the color pigment is visible. Thus, the color pigment forms a visually perceptible marking 60 indicating that the aerosol-generating article 10 has been used. This embodiment is less susceptible to ambient moisture because the increased capillary action retains ambient moisture within the stick wrap 30, thereby preventing it from coming into contact with the color pigment 62. Nevertheless, it would still be possible to provide a stick wrap with a hydrophobic, transparent outer coating to further reduce the effects of ambient moisture.

[0121] FIG. 8 illustrates various marking configurations. The marking can be, for example, the word "used" displayed on the outer surface of the aerosol-generating article 10. Furthermore, in the embodiment of FIG. 8, the marking includes a gradual progression indicating the depletion level of the aerosol-generating article 10. The gradual progression is an arrow symbol containing four segments. The first and second segments are already visible. Further segments are not yet visible and are indicated only by dotted lines. Therefore, a user can deduce from this gradual progression that the aerosol-generating article 10 is already 50 percent depleted. The amount of segments that appear in the marking depends on the amount of moisture produced, which in turn indicates how intensely the aerosol-generating article 10 has been used. Such gradual progression is not easily achieved with thermochromic inks because they are sensitive only to absolute temperature and cannot provide an indication of how long the aerosol-generating article has been exposed to such temperatures.

[0122] 9 shows an aerosol-generating article 10 comprising multiple rod-shaped elements 12, 14, 16, 18 connected together by stick wrap 30. Stick wrap 30 is made from conventional cigarette paper. Aerosol-generating article 10 comprises four elements: a front plug 12, a sensory media plug 14 containing an aerosol-forming substrate 15, a hollow acetate tube 16, and a mouthpiece filter 18.

[0123] The sensory media plug and hollow acetate tube are packaged separately within plug wraps 34, 36. The plug wrap 36 of the hollow acetate tube 16 is marked with marking 60 in the form of a printed graphic icon. The icon shows a red triangle with an exclamation point. The aerosol-generating article 10 further comprises a capillary element in the form of a capillary thread 64. The capillary thread 64 extends essentially the entire length of the aerosol-generating article 10.

[0124] In the center view of Figure 9, the aerosol-generating article 10 is shown in a fully assembled state. A stick wrap 30, which is a conventional cigarette paper, extends across the complete aerosol-generating article 10 and binds the individual elements together, including the capillary strands 64. Unless the aerosol-generating article 10 is in use, the stick wrap 30 is dry and opaque. In this state, the stick wrap 30 also covers the marking 60, which is therefore invisible or only slightly visible to the user.

[0125] The bottom diagram in Figure 9 shows the aerosol-generating article 10 after use. Moisture generated during use diffuses through the capillary threads 64 throughout the entire length of the aerosol-generating article 10. A portion of the stick-wrap 30 has reacted with this moisture and become less opaque during use. This portion, including the area of ​​the hollow acetate tube 16 where the marking 60 is applied, is the water-colored portion 50 of the stick-wrap 30. Because this portion has become less opaque, the marking 60 underneath is clearly visible. The change in contrast ratio of the marking 60 between an unused aerosol-generating article 10 and a used aerosol-generating article 10 is approximately 4. Therefore, a user can now clearly and easily distinguish between a used aerosol-generating article 10 and an unused aerosol-generating article 10.

Claims

1. An electrically heated aerosol generating article, Multiple elements, including one or more of a front-end filter, a hollow acetate tube, and a cardboard tube, are disposed at the upstream end of the aerosol generating article. The aerosol generating article comprises a stick wrap configured to connect the elements, The aerosol generating article is further configured to display a visually perceptible marking when it comes into contact with the moisture of the stick wrap, and is an electrically heated aerosol generating article.

2. The electrically heated aerosol generating article according to claim 1, wherein at least a portion of the stick wrap is configured as a water-color-reactive portion that changes color or opacity upon contact with moisture.

3. The electrically heated aerosol generating article according to claim 2, wherein the water-coloring portion of the stick wrap covers a portion of the outer surface of the element, the portion of the outer surface of the element is marked, and the water-coloring portion of the stick wrap is configured to decrease in opacity when in contact with moisture.

4. The electrically heated aerosol generating article according to claim 2, wherein the stick wrap is substantially transparent, and the stick wrap comprises a water-color-developing portion that is opaque in a dry state, and the opacity of the water-color-developing portion decreases when it comes into contact with moisture.

5. The electrically heated aerosol generating article according to claim 2, wherein the water-color-developing portion of the stick wrap is configured to change color upon contact with moisture.

6. The electrically heated aerosol generating article according to claim 5, wherein the water-color-developing portion of the stick wrap is configured to have the same or similar color as the stick wrap before contact with moisture, and the water-color-developing portion of the stick wrap is further configured to change color upon contact with moisture.

7. The electrically heated aerosol generating article according to claim 1, wherein the aerosol generating article contains a coloring pigment that is transported to the outer surface of the stick wrap by moisture and capillary action of the stick wrap.

8. The electrically heated aerosol generating article according to claim 2, wherein the moisture generated by the condensation of heated air or aerosol comes into contact with the water-coloring portion of the stick wrap.

9. The electrically heated aerosol generating article according to claim 8, wherein the marking is configured to indicate the amount of moisture received in the marking zone.

10. The electrically heated aerosol generating article according to claim 1, wherein the aerosol generating article comprises an element that enhances capillary action for transporting the moisture to a dedicated portion of the aerosol generating article.

11. The electrically heated aerosol generating article according to claim 1, wherein one or more of the elements may be perforated or open to enhance the radial movement of moisture from the airflow channel toward the stick wrap.

12. The electrically heated aerosol generating article according to claim 1, wherein the stick wrap is covered with a hydrophobic layer.

13. The electric heating aerosol generating article according to claim 2, wherein the change in color or opacity of the water-colored portion is irreversible.

14. Aerosol generator and an aerosol generating system comprising an electrically heated aerosol generating article according to any one of claims 1 to 13.

15. A method for manufacturing an electrically heated aerosol generating article, To provide a plurality of elements, including one or more of a front-end filter, a hollow acetate tube, and a cardboard tube, which are disposed at the upstream end of the aerosol generating article. To provide stick wrap, and To form the electrically heated aerosol generating article, the process includes connecting the elements by wrapping the stick wrap around the elements, A method wherein the electrically heated aerosol generating article is configured to reveal a visually perceptible marking when it comes into contact with moisture on the stick wrap.

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