Tobacco article comprising coloured wrap exterior surface and related aerosol-generating assembly

Abstract

The invention relates to a tobacco article (12) for a heated but non-fired aerosol-generating device comprising one or several heating elements, the tobacco article (12) comprising:-a tobacco substrate portion (115); -a wrap wrapping the tobacco substrate portion (115) and defining a wrap outer surface (140) intended to at least partially contact or face the or each heating element; wherein the wrap outer surface (140) is at least partially colored such that its emissivity value for infrared thermometer readings is higher than 0.85, preferably higher than 0.9.

Description

Technical Field

[0001] The present invention relates to a tobacco product for use with a heat-not-burn aerosol generating device.

[0002] In particular, the tobacco product according to the present invention is configured to operate with a heat-not-burn aerosol generating device. The tobacco product is, for example, a flat tobacco product. The tobacco product comprises, for example, a solid substrate capable of forming an aerosol when heated. Therefore, the heat-not-burn aerosol generating device is suitable for heating, rather than burning, the substrate by conduction, convection and / or radiation to produce an aerosol for inhalation.

[0003] The present invention also relates to an aerosol generating assembly comprising the heating but not burning aerosol generating device and the tobacco product. Background Art

[0004] Over the past few years, there has been a rapid growth in the popularity and use of reduced risk or modified risk devices (also known as vaporizers) to help habitual smokers who want to quit smoking to quit traditional tobacco products such as cigarettes, cigars, cigarillos and roll-ups. Rather than burning the tobacco in traditional tobacco products, a variety of different devices and systems can be used to heat or increase the temperature of the vaporizable substance.

[0005] Commonly used, risk-reduced or risk-modified devices are heated substrate aerosol generating devices or heat-but-not-burn devices. This type of device generates an aerosol or vapor by heating an aerosol substrate, typically comprising moist tobacco leaves or other suitable vaporizable materials, to a temperature typically in the range of 150°C to 350°C. Heating the aerosol substrate, but not burning or burning it, releases an aerosol that includes the ingredients desired by the user but does not include toxic and carcinogenic combustion and burning byproducts. In addition, the aerosol generated by heating tobacco or other vaporizable materials typically does not include burnt or bitter flavors that may be unpleasant to the user due to combustion and burning, and therefore, the substrate does not require sugars and other additives that are typically added to such materials to make the smoke and / or vapor more palatable to the user.

[0006] The tobacco products that can be used for this type of aerosol generating device can take many different forms. Some tobacco products can be in the form of elongated sticks or any other suitable shape, such as a flat shape. However, the design of the tobacco product is usually a compromise between its aesthetics and efficiency when heated.

[0007] In any of these cases, the tobacco substrate is surrounded by a wrapper, thereby maintaining the integrity of the tobacco product and improving the cleanliness of substrate processing. The wrapper is also intended to ensure that the steam passes through the designed path, which includes the mouthpiece portion of the product. Therefore, the wrapper makes it possible to avoid steam leakage that would reduce the overall steam efficiency.

[0008] However, the wrapper can create a thermal barrier to heat transfer from the heater of the heat-not-burn aerosol generating device to the tobacco substrate. Due to the thermal barrier, the tobacco substrate may not be fully heated, resulting in a reduced amount of vapor generated by the tobacco substrate. Summary of the invention

[0009] One of the objects of the present invention is to provide a tobacco product with improved vapor generation efficiency.

[0010] To this end, the present invention relates to a tobacco product for use in a heat-not-burn aerosol-generating device comprising one or several heating elements, the tobacco product comprising:

[0011] - tobacco matrix fraction;

[0012] - a wrapper enclosing the tobacco substrate portion and defining an outer surface of the wrapper intended to at least partially contact or face the or each heating element;

[0013] Therein, the outer surface of the wrapper is at least partially colored so that its emissivity value for infrared thermometer reading is higher than 0.85, preferably higher than 0.9.

[0014] Due to these features, the outer surface of the wrapper is colored to enhance the absorption of heat from the or each heating element. Thus, the heating of the tobacco substrate can be improved by absorbing heat from the (multiple) heaters of the device via thermal radiation. In other words, when heating, the (multiple) heaters of the device can transfer heat to the tobacco substrate via thermal convection, thermal conduction and / or thermal radiation.

[0015] Additionally, tinting can hide any stains or dirty appearance on the wrap.

[0016] If the tobacco substrate and / or wrapper is in contact with the heater(s) of the device, heat conduction between the heater(s) of the device and the tobacco substrate may be achieved.

[0017] When the tobacco substrate is generally away from the (multiple) heaters of the device, thermal convection between the (multiple) heaters of the device and the tobacco substrate can be achieved. When power is supplied, the temperature of the (multiple) heaters of the device increases, thereby generating an airflow between the (multiple) heaters of the device and the tobacco substrate. Therefore, the airflow transfers energy to the tobacco substrate to induce the temperature of the substrate to increase.

[0018] In any case, the heat radiation between the (multiple) heaters of the device and the tobacco substrate is realized. When powered, the temperature of the (multiple) heaters of the device rises. Therefore, the (multiple) heaters of the device emit radiation comprising different wavelengths. This radiation is an electromagnetic wave. The radiation reaches the outer surface of the wrapper. Depending on the material of the wrapper, the color of the wrapper and the wavelength of the emitted radiation, at least a portion of the radiant energy is absorbed by the wrapper, thereby converting the radiant energy into heat and diffusing it in the tobacco substrate.

[0019] The colored outer wrap enables absorption of radiation having a wider range of wavelengths, thus causing more energy to be absorbed and converted into heat for the tobacco substrate.

[0020] In this application, absorption is understood as the ratio of the radiant energy absorbed by the outer wrap to the radiant energy generated by the device's heater(s). Absorption is expressed as an absorptivity value, which is a measure of how much radiation is absorbed by the outer wrap.

[0021] In thermal equilibrium with the environment, the absorptivity value of a body is equal to its emissivity value. In particular, the emissivity value of a body is a measure of how much thermal radiation is emitted by that body to the environment. The emissivity value is a property of each material and for most materials it is a function of surface conditions, temperature, and the wavelength of measurement.

[0022] In the meaning of the present invention, each emissivity value is measured by an infrared thermometer reading. In particular, these measurements can be performed using a surface probe meter in combination with an infrared thermometer. For this purpose, a first temperature is read on the surface probe meter. Then, the emissivity of the infrared thermometer is varied until a second temperature given by the infrared temperature reaches the first temperature. Thus, the emissivity of the infrared thermometer corresponds to the emissivity value of the body.

[0023] For some materials, the emissivity value may vary as its temperature varies. In this case, in the meaning of the present invention, it is understood that the temperature of the outer wrapper for measuring its emissivity value is determined by the normal state of the tobacco product when it is stored when it is not in operation to generate an aerosol (e.g. 20° C.). In a variant, the temperature of the outer wrapper for measuring its emissivity value is determined by the tobacco product in an operating state. This temperature may be comprised between 200° C. and 350° C.

[0024] According to some embodiments, the emissivity value of the outer surface of the wrapping for infrared thermometer readings is comprised between 0.90 and 0.98, preferably between 0.91 and 0.96, and advantageously between 0.92 and 0.95, and even more preferably between 0.93 and 0.94.

[0025] By virtue of this feature, the heat absorption of the outer surface of the wrapping is optimized, since the emissivity values ​​comprised in said interval make it possible to absorb the vast majority of the energy received.

[0026] According to some embodiments, the color of the outer surface of the wrapper is obtained by mixing several dyes, advantageously four dyes.

[0027] This feature improves the absorbency of the wrapper, since it ensures that the wrapper absorbs the energy of radiation having different wavelengths corresponding to the color of each dye. The heating of the tobacco substrate is thus improved.

[0028] According to some embodiments, the color of each dye is selected from the group consisting of: a red dye, a green dye, a blue dye, and a yellow dye.

[0029] This feature makes it possible to improve the heating of tobacco substrate by optimizing the wavelength absorbed. In fact, red, blue and yellow are evenly distributed in the visible spectrum. Blue corresponds to the wavelength included between 380nm and 500nm. Green corresponds to the wavelength included between 500nm and 580nm. Yellow corresponds to the wavelength included between 580nm and 590nm. Red corresponds to the wavelength included between 620nm and 780nm.

[0030] As known per se, each color reflects the wavelength corresponding to said color and absorbs other wavelengths. In particular, the wavelength opposite to the wavelength of the color is absorbed the most.

[0031] Thus, the color of the outer surface of the wrapper can be yellow, red, green, blue or black. The black color defined herein is the color obtained when each dye is mixed. The emissivity value of the outer surface of the wrapper having one of these colors depends on the properties of the dye. For example, for some dyes, the emissivity value can be included between 0.90 and 0.95.

[0032] According to some embodiments, the dye is a food dye.

[0033] By virtue of this feature, the dye does not present any risk to the user of the heat-not-burn aerosol device.

[0034] According to some embodiments, the wrap comprises a vapor impermeable material.

[0035] This feature avoids steam leakage which would reduce steam efficiency.

[0036] According to some embodiments, the vapor barrier material is aluminum.

[0037] With this feature, vapor leakage is further retained because aluminum is a highly effective vapor barrier material.

[0038] According to some embodiments, the colored partial area of ​​the outer surface of the wrapper accounts for more than 50%, preferably more than 60%, advantageously more than 70% and more advantageously more than 80% of its total area.In some embodiments, the outer surface of the wrapper is completely colored.

[0039] In some embodiments, the coloured portion of the outer surface of the wrapper corresponds to a portion of the outer surface of the wrapper that is intended to face or contact one or several heating elements of the aerosol-generating device.

[0040] Due to these features, the colored portion of the outer surface of the wrap can be optimized for absorbing heat. In addition, depending on different embodiments of the present invention, the colored portion can form a special design effect of the wrap.

[0041] According to some embodiments, the wrapper comprises paper and the color of the outer surface of the wrapper is obtained by coloring the paper.

[0042] This feature makes it easy to color at least a portion of the wrapper. In fact, it is easy to surface treat the paper. Due to the high absorption capacity of paper for liquids and powders, different coloring processes can be used on the paper.

[0043] For example, the paper can be at least partially immersed in the coloring liquid, thereby absorbing the liquid. During the drying process, the water will evaporate from the paper, and only the pigment in the coloring liquid will remain on the paper.

[0044] Alternatively, the coloring liquid can be sprayed on those portions of the paper where the colored portion is intended to be formed. Due to the high absorption capacity of the paper, the coloring liquid will be absorbed by the paper instead of diffusing from the paper. During the drying process, the water will evaporate and only the pigment in the coloring liquid will remain on the paper.

[0045] According to some embodiments, the dye is added to the pulp of the paper forming the wrapper.

[0046] By virtue of this feature, when paper is manufactured, the paper is fully colored so that it is possible to ensure that the coloring dye is evenly distributed in the paper material.

[0047] Then, when the tobacco product is used with a heat-not-burn aerosol-generating device, the heat radiation will have a uniform effect on the outer surface of the wrapper, thereby improving vapour efficiency.

[0048] According to some embodiments, the weight fraction of each dye in the pulp is comprised between 0.1% and 5%.

[0049] This feature enables the wrapper to be coloured whilst remaining harmless to users of the tobacco product.

[0050] According to some embodiments, the outer surface of the wrap is matte.

[0051] By virtue of this feature, a smaller portion of the radiation emitted by the (multiple) heaters of the device is reflected by the outer surface of the wrapper. In fact, when the radiation reaches the surface, part of the radiation will be reflected by the surface, regardless of the color of the surface. This phenomenon is called reflection. The matte surface has a low reflectivity, ensuring that the energy of the radiation is better absorbed. Therefore, this feature improves the heating of the tobacco substrate.

[0052] A matte surface may be a surface having a specular reflectance below 20 GU at a measurement angle of 60°. The specular reflectance is preferably below 10 GU at a measurement angle of 60°.

[0053] According to some embodiments, it is defined as a flat, preferably a flat cuboid.

[0054] According to some embodiments, the color of the outer surface of the wrapper is selected to absorb radiation having wavelengths comprised between 600 nm and 2.5 μm more than radiation having other wavelengths.

[0055] This feature makes it possible to improve the absorption of the most dominant wavelengths among the wavelengths emitted by the heater of the device. In particular, the wavelengths emitted by the heater of the device may include at least some wavelengths from the visible spectrum (for example between 600 nm and 700 nm) and at least some wavelengths from the infrared spectrum (from 700 nm to 2.5 μm). Thus, the absorption of thermal radiation by the outer surface of the wrapping can be optimized.

[0056] The present invention also relates to a tobacco product as described above and a heat-not-burn aerosol-generating device adapted to operate with the tobacco product. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] The invention and its advantages will be better understood on reading the following description, given by way of non-limiting example only and made with reference to the accompanying drawings, in which:

[0058] - Figure 1 is a perspective view of an aerosol generating assembly according to the present invention, the aerosol generating assembly comprising a heat-not-burn aerosol generating device and a tobacco product according to the present invention, the tobacco product being usable with the aerosol generating device;

[0059] - Figure 2 yes Figure 1 The aerosol generating assembly is based on Figure 1 A partial cross-sectional view of a longitudinal vertical plane;

[0060] - Figure 3 yes Figure 1 A three-dimensional image of a tobacco product;

[0061] - Figure 4 yes Figure 3 of tobacco products according to Figure 3 A partial cross-sectional view of the longitudinal vertical plane. DETAILED DESCRIPTION

[0062] Before describing the present invention, it should be understood that the present invention is not limited to the construction details set forth in the following description. For those skilled in the art who benefit from this disclosure, it is obvious that the present invention is capable of other embodiments and can be practiced or implemented in a variety of different ways.

[0063] As used herein, the term "substantially equal to" defines equality within a range of plus or minus 10%, and preferably equality within a range of plus or minus 5%.

[0064] As used herein, the term "aerosol generating device" or "device" can include a device for inhalation that delivers an aerosol (including an aerosol for inhalation) to a user by a heater element described in further detail below. The device can be portable. "Portable" can refer to that the device is used when held by a user. The device can be suitable for, for example, producing a variable amount of aerosol (different from a quantitative aerosol) by activating a heater element for a variable period of time, which can be controlled by a trigger. The trigger can be user-activated, such as an inhalation button and / or an inhalation sensor. The inhalation sensor can be sensitive to inhalation intensity and inhalation duration, so that a variable amount of steam can be provided (so as to simulate the effect of traditional combustible smoking articles such as cigarettes, cigars or pipes). The device can include a temperature control component to drive the temperature of the heater and / or heated aerosol-generating material (aerosol precursor) to reach a specified target temperature and thereafter the temperature is maintained at a target temperature that can effectively produce an aerosol.

[0065] As used herein, the term "aerosol" may include a suspension of vaporizable material such as one or more of the following: solid particles; liquid droplets; gas. The suspension may be in a gas (including air). Aerosol herein may generally refer to / include vapor. Aerosol may contain one or more components of vaporizable material.

[0066] As used herein, the term "vaporizable material" or "precursor" may refer to a material that can be ignited and smoked, which can, for example, include nicotine or tobacco and an aerosol former. Tobacco can take the form of a variety of different materials, such as shredded tobacco, granulated tobacco, tobacco leaves and / or reconstituted tobacco. Suitable aerosol formers include: polyols, such as sorbitol, glycerol, and glycols (such as propylene glycol or triethylene glycol); non-polyols (such as monohydric alcohols), acids (such as lactic acid), glycerol derivatives, esters (such as triacetin, triethylene glycol diacetate, triethyl citrate, glycerol or vegetable glycerin). In some embodiments, the aerosol generator can be glycerol, propylene glycol, or a mixture of glycerol and propylene glycol. The matrix can also include at least one of a gelling agent, a binder, a stabilizer, and a wetting agent.

[0067] Figure 1 An aerosol-generating assembly 10 is shown comprising a heat-not-burn aerosol-generating device 11 and a tobacco product 12. The heat-not-burn aerosol-generating device 11 is intended to operate with the tobacco product 12.

[0068] refer to Figure 1 The heating-but-not-burning aerosol-generating device 11 comprises a device body 40 and a mouthpiece 42 extending along a device axis Y. According to the example described below, the mouthpiece 42 and the device body 40 form two different pieces. In particular, according to this example, the mouthpiece 42 is designed to be fixed on a fixed end of the device body 40.

[0069] like Figure 2 As shown, the mouthpiece 42 includes a central portion 43 and a peripheral portion 44 extending around the central portion 43. When the mouthpiece 42 is fixed to the fixed end of the device body 40, the peripheral portion 44 defines a collar that, for example, partially covers the outer surface of the device body 40. For example, the peripheral portion 44 can be designed to cooperate with a gasket 45 arranged on the fixed end of the device body 40 to seal the space formed between the peripheral portion 44 and the outer surface of the device body 40. The peripheral portion 44 also defines a middle portion that, for example, extends transversely to the device axis Y and forms a transition between the central portion 43 of the mouthpiece 42 and the collar defined by the peripheral portion 44. The central portion 43 of the mouthpiece 42 defines a through hole 46 that is suitable for at least partially receiving the tobacco product 12. Advantageously, the through hole 46 can be suitable for closely fitting with the tobacco product 12, thereby avoiding or minimizing the flow leakage between the wall defining the through hole 46 and the outer surface of the tobacco product 12. In some embodiments, the tobacco product 12 can be retained by, for example, friction in the through hole 46. In this case, it is possible, for example, to first insert the tobacco article 12 inside the through hole 46 and then to fix both elements to the fixed end of the device body 40 .

[0070] like Figure 2As also shown in the figure, an internal volume 47 is formed between the inner surface 48 of the mouthpiece 42 and the fixed end of the device body 40. When the tobacco product 12 is inserted into the interior of the device body 40, this internal volume 47 is penetrated by the tobacco product. For example, the tobacco product 12 can divide the internal volume 47 into two symmetrical parts.

[0071] The device body 40 defines an interior space of the device 11 that receives a variety of different components designed to perform different functions of the device 11. The interior space may, for example, receive a battery for powering the device 11, a control module for controlling the operation of the device 11, a heating chamber 50 for heating the tobacco product 12, etc. Among these components, only reference is made to Figure 2 The heating chamber 50 is explained in further detail.

[0072] In particular, as in Figure 2 , the heating chamber 50 can be formed into a cup shape suitable for at least partially receiving the tobacco product 12. The heating chamber 50 can also be formed into a rectangular parallelepiped shape, which extends along the device axis Y and includes a pair of parallel wide walls 54A, 54B also extending along the device axis Y, a pair of parallel narrow walls not shown extending along the device axis Y, and a bottom wall 58 adjacent to each of the walls and extending perpendicular to the device axis Y. The bottom wall 58 thus forms a closed end of the chamber 50. Opposite to the bottom wall 58, the heating chamber 50 defines an opening 60 configured to receive the tobacco product 12.

[0073] The heating chamber 50 further comprises one or more heating elements (not shown), and this one or more heating elements are arranged to heat the matrix part 15 of tobacco product 12.According to different embodiments of the present invention, this or each heating element can present the resistance element of at least one of the wide wall 54A, 54B or the narrow wall that is arranged adjacent to the heating chamber 50.The resistance element can be ceramic.Advantageously, the resistive heating element (just as for example heating track or film heater) is arranged to each wide wall 54A, 54B adjacent to the heating chamber 50, for example on the outer surface of such wall.In this case, each wide wall 54A, 54B is made of heat-conducting material (such as metal or ceramic).In certain embodiments, this or each heating element is integrated into corresponding wide wall 54A, 54B or forms such wall.

[0074] When powered, one or more heating elements emit radiation comprising one or more wavelengths. These wavelengths can be mainly included between 600nm and 2.5 μm, corresponding to at least part of the infrared wavelength and at least part of the visible wavelength. When this heating element is arranged to be adjacent to the corresponding wide wall 54A, 54B, this wall is heated and therefore also emits radiation comprising one or more wavelengths. The energy of this radiation is subsequently at least partially absorbed by tobacco product 12, as described below.

[0075] In order to ensure the user's inhalation, an airflow channel, not shown, is formed inside the aerosol generating device 11. The airflow channel may, for example, extend between the airflow inlet and the closed end of the heating chamber 50. According to some embodiments, the airflow inlet is arranged in the mouthpiece 42, advantageously in the middle part of the peripheral part 44 of this mouthpiece 42. The airflow inlet may be formed by a through hole.

[0076] The airflow channel is formed by an upstream portion extending from the airflow inlet and a downstream portion extending from the upstream portion to the closed end of the heating chamber 50. According to different embodiments of the present invention, the downstream portion may extend inside or outside the heating chamber 50. For example, according to one embodiment, the downstream portion extends inside the heating chamber 50 from the opening 60 of the heating chamber to the closed end.

[0077] In some embodiments, several airflow channels may be formed inside the aerosol generating device 11, each of which is similar to the channels described above. For example, these channels may be arranged symmetrically with respect to the through hole 46 of the mouthpiece 42. In the example of the accompanying drawings, two airflow channels are arranged symmetrically with respect to the through hole 46.

[0078] In this Figure 3 In the example of, tobacco product 12 is a flat tobacco product, presenting a flat cuboid extending along the product axis X and having an outer dimension of L x W x D. In a typical example, the length L of product 12 according to product axis X is substantially equal to 33mm, and its width W and depth D are substantially equal to 12mm and 1.2mm respectively. According to different examples, for example, the values ​​of L, W and D can be selected within the range of + / -40%. The depth D of tobacco product 12 is formed by a pair of parallel walls 113A, 113B (hereinafter referred to as narrow walls 113A, 113B), and the width W of the matrix is ​​formed by a pair of parallel walls 114A, 114B (hereinafter referred to as wide walls 114A, 114B). Tobacco product 121 has a flat shape. In some embodiments, the edge between narrow walls 113A, 113B and wide walls 114A, 114B can be rounded. According to other embodiments of the present invention, tobacco product 12 can have any other suitable flat shape and / or outer dimensions. According to other embodiments, tobacco article 12 may be in any other suitable shape (eg, a stick shape).

[0079] The tobacco product 12 comprises a tobacco substrate portion 115 and a mouthpiece portion 116 arranged along an axis X of the product. The substrate portion 115 may, for example, be slightly longer than the mouthpiece portion 16. For example, the length L2 of the substrate portion 15 according to the axis X of the product may be substantially equal to 18 mm, and the length L1 of the mouthpiece portion 16 according to the axis X of the product may be substantially equal to 15 mm. The substrate portion 115 defines an abutment end 118 of the product 12, and the mouthpiece portion 116 defines a mouth end 120 of the product 12. The substrate portion 115 and the mouthpiece portion 116 may be secured to each other by a wrapper 121 extending around the substrate axis X (described in detail below).

[0080] The mouthpiece portion 116 includes a core 127, which is intended to be used, for example, as a cooler to slightly cool the vapor before it is inhaled by the user. For this purpose, the core 127 may include, for example, corrugated paper. The core 127 may be formed into a stable shape by an extrusion and / or rolling process. Advantageously, the core 127 is arranged inside the mouthpiece portion 116 to be in full contact with an inner surface 128 of the wrapper 121 that defines this mouthpiece portion 116.

[0081] The mouthpiece portion 116 is, for example, intended to be received by the through-hole 46 when the tobacco article 12 is received in the device 11 .

[0082] The substrate portion 115 comprises a vaporisable material (as defined above) and is intended to be heated by the heating chamber 50. The substrate portion 115 is intended to be received in the heating chamber 50, for example, when the tobacco article 12 is received in the device 11.

[0083] In particular, refer again to Figure 2 , the tobacco product 12 is intended to be at least partially inserted into the heating chamber 50. The tobacco product 12 is configured to be received in the opening 60 of the heating chamber 50 so that the corresponding wide walls 114A, 114B of the tobacco product 12 face the corresponding wide walls 54A, 54B of the heating chamber 50, the corresponding narrow walls 113A, 113B of the tobacco product 12 face the corresponding narrow walls of the heating chamber 50, and the abutment end 118 of the tobacco product 12 abuts on the bottom wall 58 or on a rib extending from at least this bottom wall 58. Alternatively, the abutment end 118 of the tobacco product 12 faces the bottom wall 58 without contacting it. The tobacco product 12 is thus configured to be received by the heating chamber 50 so that the narrow wall 113A (respectively, 113B) of the tobacco product 12 faces the narrow wall of the heating chamber 50, and the wide wall 114A (respectively, 114B) of the tobacco product 12 faces the wide wall 54B (respectively, 54A) of the heating chamber 50. The facing wide walls 114A, 114B, 54A, 54B and the facing narrow walls 113A, 113B may contact each other or be spaced apart from each other.

[0084] If the facing wide walls 114A, 114B, 54A, 54B and the facing narrow walls 113A, 113B are in contact with each other, the heat generated by the heating element is mainly transferred to the tobacco substrate portion 115 via heat conduction. If the facing wide walls 114A, 114B, 54A, 54B and the facing narrow walls 113A, 113B are not in contact with each other, the heat generated by the heating element is mainly transferred to the substrate portion 115 via heat convection. In both cases, a portion of the heat is transferred from the heating element to the substrate portion 115 via heat radiation.

[0085] refer to Figure 2 , when the tobacco product 12 is inserted into the heat-but-not-burn aerosol-generating device 11, a downstream portion of the airflow channel may be formed between the narrow walls 113A, 113B of the tobacco product 12 and the corresponding narrow walls of the heating chamber 50. According to another embodiment, the downstream portion of the airflow channel extends to the outside of the heating chamber 50 through, for example, a dedicated channel extending along the narrow wall of the heating chamber 50. In this case, the downstream portion leads to the closed end of the heating chamber 50.

[0086] When the aerosol assembly is used, air can enter the heating chamber 50 through the airflow channel and first pass through the substrate portion 115, then pass through the mouthpiece portion 116 of the tobacco article 12, and finally be delivered to the user.

[0087] The wrapper 121 forms the narrow walls 113A, 113B and the wide walls 114A, 114B of the tobacco article 12. Preferably, the wrapper 121 covers neither the abutment end 118 nor the mouth end 120. Alternatively, the abutment end 118 and / or the mouth end 120 are covered by a removable portion(s) of the wrapper 121. This or these removable portions should be removed from the article 12 before inserting the article 12 into the device 11.

[0088] In some embodiments, the wrap 121 is formed by the same wrap sheet. In other embodiments, several wrap sheets (eg, two) can form the wrap 121.

[0089] exist Figure 4 In the example of FIG. 1 , the wrapper 121 includes a first layer 131 and a second layer 132. According to other examples, the wrapper 121 may be formed of a single layer.

[0090] The first layer 131 surrounds the tobacco substrate portion 115, thereby defining an inner surface 135 of the wrapper 121 that contacts the tobacco substrate. The first layer 131 can be made of a vapor-impermeable material to prevent vapor from leaking from the first layer. The first layer 131 can be made of aluminum, preferably aluminum backing paper.

[0091] The second layer 132, for example, surrounds the first layer 131, thereby defining an outer surface 140 of the wrapper 121. The outer surface 140 is intended to face the wide walls 54A, 54B and the narrow wall of the heating chamber 50 when the tobacco article 12 is inserted into the heat-not-burn aerosol-generating device 11. The second layer 132 may include paper and is preferably made of paper.

[0092] When the wrapper 121 is formed of a single layer, both the inner surface 135 and the outer surface 140 are formed of this single layer. In this case, this single layer can be formed of any suitable material (such as paper, aluminum, etc.). Hereinafter, when referring to the second layer 132, this second layer 132 can be considered to be a single layer of the wrapper 121 or a part of the wrapper 121 combined with the first layer 131. It is also considered that the second layer 132 includes paper or is formed of paper.

[0093] The outer surface 140 is at least partially colored to enhance the absorption of heat from the heating element(s). The colored portion of the outer surface of the wrap corresponds to, for example, a portion of the outer surface of the wrap that is intended to face or contact one or more heating elements. The color of the outer surface 140 can be any color of the visible spectrum that enhances the absorption of heat. The visible spectrum must be understood here as being included between 400nm and 800nm.

[0094] For example, the outer surface 140 can be colored with a dark color, such as black, purple, or indigo. In other words, the outer surface does not reflect substantially any light. Preferably, when the wavelengths are different, for each wavelength, the outer surface 140 does not reflect more than 10% of the energy in the radiation corresponding to the wavelength.

[0095] The colored outer surface 140 may be formed by applying a dye (e.g., food dye) to the material forming the wrap 121 (i.e., Figure 4 The second layer 132 material in the example is obtained by coloring.

[0096] As an example, a combination of four dyes (e.g., red, green, blue, and yellow) enables the outer surface 140 to be colored in a black-like manner. In fact, red, green, blue, and yellow are primary and secondary colors of subtractive color synthesis. By subsequently mixing these four colors, black can be obtained substantially.

[0097] The red dye is, for example, Allura Red AC, also known as E129 dye. Its chemical formula is C 18 H 14 N 2 Na 2 O 8 S 2, whose full name is disodium 6-hydroxy-5-[(2-methoxy-5-methyl-4-sulfonate phenyl)diazenyl]naphthalene-2-sulfonate. The weight fraction in the second layer 132 may be comprised between 0.1% and 5%, for example. The absorption spectrum of the red dye reaches a maximum at 504nm.

[0098] Green dye is for example Fast Green FCF, also known as E143 dye. Its chemical formula is C 37 H 34 N 2 Na 2 O 10 S 3 , whose full name is ethyl-[4-[[4-[ethyl-[(3-sulfonylphenyl)methyl]amino]phenyl]-(4-hydroxy-2-sulfonylphenyl)methylene]-1-cyclohex-2,5-dienyl]-[(3-sulfonylphenyl)methyl]ammonium nitrogen. The weight portion in the second layer 132 may be included, for example, between 0.1% and 5%. The absorption spectrum of the green dye reaches a maximum at 625nm.

[0099] The blue dye is for example Brilliant Blue FCF, also known as E133 dye. Its chemical formula is C 37 H 34 N 2 Na 2 O 9 S 3 And its full name is disodium; 2-[[4-[ethyl-[(3-sulfonate phenyl)methyl]amino]phenyl]-[4-[ethyl-[(3-sulfonate phenyl)methyl]nitro]cyclohexa-2,5-diene-1-ylidene]methyl]benzenesulfonate. The weight portion in the second layer 132 may be, for example, included between 0.1% and 5%. The absorption spectrum of the blue dye reaches a maximum at 630nm.

[0100] Yellow dyes are for example tartrazine, also known as E102 dye. Its chemical formula is C 16 H 9 N 4 Na 3 O 9 S 2 , whose full name is trisodium 5-hydroxy-1-(4-sulfonate phenyl)-4-[(E)-(4-sulfonate phenyl)diazenyl]-1H-pyrazole-3-carboxylate. The weight fraction in the second layer 132 may be comprised between 0.1% and 5%, for example. The absorption spectrum of the yellow dye reaches a maximum at 425nm.

[0101] The emissivity values ​​of the outer surface 140 of the wrapper for infrared thermometer readings are comprised between 0.90 and 0.99, preferably between 0.90 and 0.98, more preferably between 0.91 and 0.96, and advantageously between 0.92 and 0.95, and even more preferably between 0.93 and 0.94. These values ​​can be measured when the tobacco product 12 is not operated to generate aerosol and is stored at ambient temperature (e.g., 20°C).

[0102] Furthermore, the outer surface 140 may be matte. Matte properties are optical characteristics characterized by the reflection of light in a specular direction. The matte properties of the outer surface 140 make it possible to limit the amount of radiant energy reflected from the heating element.

[0103] A matte surface may be a surface having a specular reflectance below 20 GU at a measurement angle of 60°. The specular reflectance is preferably below 10 GU at a measurement angle of 60°.

[0104] During the manufacture of the second layer 132, the paper can be in the form of pulp forming paper. Each dye is added to the pulp forming paper. Preferably, each dye is diluted with water so that the dye is better diffused in the pulp forming paper. Alternatively, each dye is in the form of a powder. Therefore, the pulp is mixed so that each dye is evenly distributed in the pulp. Then, according to known papermaking processes, the paper is manufactured. Finally, the colored paper is ready to form the second layer 132 of the wrapper 121.

[0105] In some non-illustrated embodiments, the wrapper 121 is formed of separate wrapping sheets that wrap the portions 115, 116 individually and are secured to each other by any other suitable means. In this embodiment, the wrapping sheet that wraps the tobacco substrate portion 115 is similar to the wrapper 121 described above. Therefore, it is apparent that the outer surface of the wrapping sheet that wraps the tobacco substrate portion 115 is colored.

[0106] In these embodiments, the wrapping sheet wrapping the mouthpiece portion 116 can be similar to the wrapping sheet wrapping the tobacco substrate portion 115. In this case, the outer surface of the wrapping sheet wrapping the mouthpiece portion 116 is also colored. Alternatively, the wrapping sheet wrapping the mouthpiece portion 116 is white.

[0107] Operation of the aerosol generating assembly

[0108] The operation of the aerosol generating assembly 10 will now be described.

[0109] First, the tobacco article 12 is inserted into the device 11 so that the tobacco substrate portion 115 faces the heating element.

[0110] The heating element generates heat. If the outer surface 140 is in contact with the heating element, the heat is transferred to the tobacco substrate portion 116 by conduction. If the outer surface 140 is not in contact with the heating element, the heat is transferred by convection.

[0111] In addition, the heat generated by the heating element causes it to emit radiation toward the tobacco product 12. The radiation reaches the outer surface 140, wherein the wrapper 121 absorbs a first portion of the radiation and reflects a second portion thereof. Because the outer surface is colored, the wrapper 121 absorbs most of the energy of the radiation, primarily when the outer surface 140 has a dark color (such as black). This absorption contributes to heating the tobacco substrate portion 116. In effect, the energy absorbed by the wrapper 121 is converted by the wrapper 121 into heat.

[0112] During the user's inhalation, air from outside the aerosol generating device 11 flows through the airflow channel and reaches the heating chamber 50. The air then enters the tobacco product 11 through the abutment end 118 and reaches the tobacco substrate portion 115. In the tobacco substrate portion 115, the air mixes with the tobacco vapor to form an aerosol. In the mouthpiece portion 116, the aerosol is cooled before reaching the user's mouth.

Claims

1. A tobacco product (12) for use in a heat-not-burn aerosol generating (11) device comprising one or more heating elements, the tobacco product (12) comprising: - a tobacco substrate portion (115); - a wrapper (121) wrapping the tobacco substrate portion (115) and defining an outer wrapper surface (140) intended to at least partially contact or face the or each heating element; Therein, the outer surface (140) of the wrapper is at least partially colored so that its emissivity value for infrared thermometer reading is higher than 0.85, preferably higher than 0.

9.

2. The tobacco product (12) according to claim 1, wherein: The emissivity value of the outer surface (140) of the wrapping for infrared thermometer readings is comprised between 0.90 and 0.98, preferably between 0.91 and 0.96, and advantageously between 0.92 and 0.95, and even more preferably between 0.93 and 0.

94.

3. The tobacco product (12) according to claim 1 or 2, wherein: The color of the outer surface (140) of the wrapper is obtained by mixing several dyes, advantageously four dyes.

4. The tobacco product (12) according to claim 3, wherein: The color of each dye is selected from the group consisting of a red dye, a green dye, a blue dye, and a yellow dye.

5. The tobacco product (12) according to claim 3 or 4, wherein: The dye is a food dye.

6. The tobacco product (12) according to any one of the preceding claims, wherein: The wrap (121) includes a vapor barrier material (131).

7. The tobacco product (12) according to any one of the preceding claims, wherein The area of ​​the colored portion of the outer surface (140) of the wrapper is greater than 50%, preferably greater than 60%, advantageously greater than 70% and more advantageously greater than 80% of its total area.

8. The tobacco product (12) according to any one of the preceding claims, wherein The wrapper (121) comprises paper.

9. The tobacco product (12) according to claim 8, wherein: The colour of the outer surface of the wrapper is obtained by colouring the paper.

10. The tobacco product (12) according to claim 8 or 9 in combination with claim 3, wherein: The dye is added to the pulp of the paper forming the wrapper (121).

11. The tobacco product (12) according to claim 10, wherein: The weight fraction of each dye in the pulp is comprised between 0.1% and 5%.

12. The tobacco product (12) according to any one of the preceding claims, wherein The outer surface (140) of the wrap is matte.

13. The tobacco article (12) according to any one of the preceding claims, defining a flat, preferably a flat cuboid.

14. The tobacco product (12) according to any one of the preceding claims, wherein The color of the outer surface (140) of the wrapper is selected to absorb radiation having wavelengths comprised between 600 nm and 2.5 μm more than radiation having other wavelengths.

15. An aerosol generating assembly (10), comprising: - A tobacco product (12) according to any one of the preceding claims; - a heat-not-burn aerosol-generating device (11) adapted to operate with said tobacco product (12).

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