Method for sealing the end face of a heated cigarette and device for sealing the end face of a heated cigarette

Abstract

This application provides a method and apparatus for sealing the end face of a heated cigarette, relating to the field of heated cigarette technology. The end face sealing method includes: cutting a substrate to form a sealing film that matches the end face shape of the main body of the heated cigarette, the sealing film including an adhesive layer and a protective layer stacked together; heating the adhesive layer to melt it; placing the end face of the tobacco segment of the formed cigarette body towards the adhesive layer; and pressing the heated sealing film against the end face to bond the molten adhesive layer to the end face.

Description

Technical Field

[0001] At least one embodiment of this application relates to the field of heated cigarette technology, and more particularly to a method and device for sealing the end face of a heated cigarette. Background Technology

[0002] Heated cigarettes are a new type of tobacco product that produces an aerosol by heating rather than burning tobacco materials. In actual use, when the cigarette is pulled out of the heating device, the tobacco shreds at the end face often fall off, become loose, or crumble, affecting the user experience; at the same time, the exposed tobacco shreds are also prone to absorbing moisture, losing their aroma, or becoming contaminated. Summary of the Invention

[0003] In view of this, this application provides a method and device for sealing the end face of heated cigarettes, which can achieve efficient, precise and reliable bonding between the sealing film and the end face of the cigarette body without damaging the outer layer of the sealing film and the quality of the tobacco.

[0004] As one aspect of this application, a method for sealing the end face of a heated cigarette is provided, comprising:

[0005] The substrate is cut to form a sealing film that matches the end face shape of the main body of the heated cigarette. The sealing film includes an adhesive layer and a protective layer stacked together.

[0006] The adhesive layer is heated to melt it;

[0007] The end face of the tobacco section of the formed cigarette body is facing the above-mentioned adhesive layer;

[0008] The heated sealing film is pressed against the end face to bond the molten adhesive layer to the end face.

[0009] According to an embodiment of this application, the heating method for heating the adhesive layer includes infrared radiation heating, wherein the radiation wavelength of the infrared radiation heating matches the infrared absorption peak of the adhesive layer material.

[0010] According to an embodiment of this application, the heating method for heating the above-mentioned adhesive layer includes hot air heating, wherein the hot air temperature is 100℃-150℃ and the hot air velocity is 5m / s-20m / s.

[0011] According to an embodiment of this application, the melting point of the protective layer is higher than that of the adhesive layer.

[0012] According to an embodiment of this application, the above-mentioned end-face sealing method further includes: cooling the cigarette body bonded to the sealing film to accelerate the curing of the adhesive layer.

[0013] According to an embodiment of this application, the above-mentioned end-face sealing method further includes: detecting whether the overlapping area of ​​the sealing film and the end face is within a preset range; if the overlapping area is not within the preset range, rejecting heated cigarettes whose overlapping area is lower than the preset range.

[0014] As another aspect of the embodiments of this application, an end-face sealing device for implementing any of the above-described end-face sealing methods is provided, comprising: a conveying mechanism adapted to convey a substrate, the substrate comprising an adhesive layer and a protective layer stacked together; a conveying mechanism adapted to cooperate with the conveying mechanism to cut the substrate into a sealing film matching the end-face shape of the cigarette body of a heated cigarette during the conveying process; a heating mechanism adapted to heat the sealing film during the conveying process of the conveying mechanism to melt the adhesive layer; and a pressing mechanism adapted to convey the cigarette body and, during the conveying process of the cigarette body, press the end face of the tobacco segment of the cigarette body against the molten adhesive layer to seal the end face.

[0015] According to an embodiment of this application, the conveying mechanism includes: a conveying roller forming a plurality of negative pressure ports evenly arranged along the circumference of the conveying roller; and a heat insulation film disposed on the circumferential surface of the conveying roller, the heat insulation film having through holes that match the plurality of negative pressure ports to adsorb the sealing film by negative pressure.

[0016] According to an embodiment of this application, the pressing mechanism includes: a pressing roller forming a plurality of receiving grooves that are recessed inward along the axial direction and correspond to the negative pressure port; the filter end of the cigarette body is inserted into the receiving groove to expose the end face; and the end face is bonded to the sealing film during the rotation of the pressing roller.

[0017] According to an embodiment of this application, the heating mechanism includes: at least one infrared radiation lamp tube adapted to emit infrared light toward the sealing film conveyed by the conveying roller; and a reflector disposed on the side of the at least one infrared radiation lamp tube facing away from the sealing film to focus the infrared light onto the sealing film.

[0018] According to the end-face sealing method of this application embodiment, the adhesive layer and protective layer are prefabricated into an integrated sealing film. During the conveying process, the sealing film is heated to melt the adhesive layer, and then pressed onto the end face of the cigarette body. This integrates the independent steps of adhesive application, film tape bonding, and heating activation in the traditional online coating process into a single online film lamination process. This avoids problems such as oxidation, carbonization, viscosity increase, and air bubble mixing caused by long-term heat preservation of hot melt adhesive in high-temperature pipelines and adhesive tanks. It also eliminates quality risks such as adhesive output fluctuations, stringing, and tailing caused by adhesive deterioration. At the same time, it eliminates the need for frequent calibration of the coating components and pipeline cleaning and maintenance, reducing equipment complexity and operating costs. The heating of the sealing film is completed during the conveying process, and only the adhesive layer of the film itself is heated. The end face of the cigarette body is not directly heated before pressing. This prevents heat from being transferred to the tobacco section through heat conduction, causing a decrease in moisture content, loss of aroma, or pyrolysis. While ensuring the bonding strength, it preserves the sensory quality of the heated cigarette to the greatest extent. Attached Figure Description

[0019] The above and other objects, features and advantages of this application will become clearer from the following description of embodiments with reference to the accompanying drawings, in which:

[0020] Figure 1 A flowchart illustrating an end-face sealing method according to an embodiment of this application is shown schematically.

[0021] Figure 2 A schematic side view of a heated cigarette according to an embodiment of this application is shown;

[0022] Figure 3 This schematic diagram illustrates the composition of an end-face sealing device according to an embodiment of the present application;

[0023] Figure 4 A partially enlarged view of the transfer roller and the pressing roller according to an embodiment of this application is shown schematically.

[0024] The annotations in the attached figures are explained as follows:

[0025] 1. Heated cigarette; 11. Cigarette body; 111. Filter section; 112. Hollow section; 113. Tobacco section; 12. Sealing film;

[0026] 2. End face sealing device; 21. Conveying mechanism; 211. Feeding roller; 212. Drive roller; 22. Conveying mechanism; 221. Negative pressure port; 23. Heating mechanism; 24. Pressing mechanism; 241. Receiving groove; 25. Rewinding roller. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with specific embodiments and the accompanying drawings.

[0028] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of this application. The terms “comprising,” “including,” etc., as used herein indicate the presence of the stated features, steps, operations, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, or components.

[0029] All terms used herein, including technical and scientific terms, have the meanings commonly understood by those skilled in the art, unless otherwise defined. It should be noted that the terms used herein are to be interpreted in a manner consistent with the context of this specification, and not in an idealized or overly rigid way.

[0030] When using expressions such as "at least one of A, B or C", they should generally be interpreted in accordance with the meaning commonly understood by those skilled in the art. For example, "a system having at least one of A, B or C" should include, but is not limited to, a system having A alone, having B alone, having C alone, having A and B, having A and C, having B and C, and / or having A, B, and C.

[0031] It should also be noted that the directional terms mentioned in the embodiments, such as "up," "down," "front," "back," "left," and "right," are only for reference to the directions in the accompanying drawings and are not intended to limit the scope of protection of this application. Throughout the drawings, the same elements are represented by the same or similar reference numerals. Conventional structures or constructions will be omitted where they may cause confusion in understanding this application.

[0032] In the process of realizing this application, it was found that the mainstream approach in related technologies is to adopt an online adhesive coating technology route, that is, first apply adhesive to the end face of the cigarette body, then attach a continuous sealing film to the coated end, activate the adhesive by heating to make the film adhere to the end face, and finally cut to obtain an independent seal.

[0033] However, this technical approach has the following problems. First, online coating requires pre-melting the hot melt adhesive into a liquid state and maintaining it at a constant temperature (usually not lower than 100°C) in the delivery pipeline, adhesive tank, and coating assembly. Hot melt adhesives are prone to oxidation, carbonization, and increased viscosity under prolonged high temperatures. In severe cases, this can lead to glue caking and carbon buildup, affecting the fluidity of the adhesive and even generating fumes. Furthermore, air bubbles may become trapped in the adhesive during the coating process, reducing bond strength and creating hidden defects.

[0034] Secondly, after applying the adhesive, a continuous sealing film strip needs to be simultaneously bonded to the adhesive-coated end. Then, a heating assembly heats both the film strip and the adhesive-coated end to activate the adhesive's viscosity. This heating method is typically contact heating, where heat is physically conducted to the sealing film strip, the adhesive layer, and the cigarette body's end face. To achieve a sufficient activation temperature for the adhesive, the heating temperature often needs to be raised to a high level. At this point, the outer layer (protective layer) of the sealing film also bears the same heat load, making it prone to melting, shrinkage, or deformation. Simultaneously, the heat from the heating assembly is transferred to the tobacco shreds through heat conduction. When the temperature of the cigarette body's end face exceeds 70°C, the moisture content of the tobacco begins to decrease; above 80°C, heat-sensitive aroma components (such as menthol and neophytadiene) begin to be significantly lost; and when the local temperature exceeds 100°C, the tobacco may even undergo slight pyrolysis, producing off-flavors or a burnt taste. This heat damage directly degrades the sensory quality of heated cigarettes.

[0035] Therefore, how to achieve efficient, precise, and reliable bonding between the sealing film and the end face of the cigarette body without damaging the outer layer of the sealing film and the quality of the tobacco has become a technical problem that urgently needs to be solved in this field.

[0036] Figure 1 A flowchart illustrating a method for sealing the end face of a heated cigarette according to an embodiment of this application is shown schematically. Figure 2 A schematic side view of a heated cigarette according to an embodiment of this application is shown.

[0037] As one aspect of this application, a method for sealing the end face of a heated cigarette is provided. For example... Figures 1-2 As shown, the end-face sealing method includes operations S100 to S130.

[0038] In operation S100, the substrate is cut to form a sealing film that matches the end face shape of the heated cigarette body. The sealing film includes an adhesive layer and a protective layer stacked together.

[0039] In operation S110, the adhesive layer is heated to melt it.

[0040] In operation S120, the end face of the tobacco section of the formed cigarette body is oriented towards the adhesive layer.

[0041] In operation S130, the heated sealing film is pressed against the end face, so that the molten adhesive layer adheres to the end face.

[0042] According to the end-face sealing method of this application embodiment, the sealing film 12, which integrates the adhesive layer and the protective layer, is prefabricated into an integrated sealing film 12. During the conveying process, the sealing film 12 is heated to melt the adhesive layer, and then pressed against the end face of the cigarette body. This integrates the steps of adhesive application, film tape bonding, and heating activation, which are performed independently in traditional online adhesive coating processes, into a single online film lamination process. This avoids problems such as oxidation, carbonization, viscosity increase, and air bubble mixing caused by long-term heat preservation of hot melt adhesive in high-temperature pipelines and adhesive tanks. It also eliminates quality risks such as adhesive output fluctuations, stringing, and tailing caused by adhesive deterioration. Furthermore, it eliminates the need for frequent calibration of the adhesive coating components and pipeline cleaning and maintenance, reducing equipment complexity and operating costs. The heating of the sealing film 12 is completed during the conveying process, and only the adhesive layer of the film itself is heated. The end face of the cigarette body is not directly heated before pressing. This prevents heat from being transferred to the tobacco section 113 through heat conduction, causing a decrease in moisture content, loss of aroma, or pyrolysis. This preserves the sensory quality of the heated cigarette 1 to the greatest extent possible while ensuring bonding strength.

[0043] According to embodiments of this application, heated cigarette 1 is a tobacco product that produces an inhalable aerosol by heating tobacco at a low temperature (e.g., 250°C to 350°C) using an external heating device, rather than by combustion. Heated cigarette 1 is often referred to as heated non-burning cigarette (HNB), low-temperature cigarette, or heated tobacco product.

[0044] The heated cigarette 1 includes a filter section 111, a hollow section 112, and a tobacco section 113 arranged sequentially along the axial direction. The filter section 111 is filled with filter fibers, such as cellulose acetate tow. The tobacco section 113 is filled with an aerosol-generating matrix. A sealing film 12 is adhered to one end of the tobacco section 113 opposite to the hollow section 112, sealing the tobacco section 113. Further, an adhesive layer is adhered to the end face of the tobacco section 113 opposite to the hollow end.

[0045] In some illustrative embodiments, the aerosol generating matrix may include at least one of reconstituted tobacco leaves, tobacco shreds, and tobacco particles.

[0046] According to an embodiment of this application, the substrate includes an adhesive layer and a protective layer stacked together. The sealing film 12 is cut from the substrate.

[0047] According to an embodiment of this application, the melting point of the protective layer is higher than that of the adhesive layer.

[0048] In some illustrative embodiments, the adhesive layer material includes ethylene-vinyl acetate copolymer (EVA).

[0049] In some illustrative embodiments, the melting point range of the adhesive layer can be configured to be greater than or equal to 50°C and less than or equal to 100°C. For example, the melting point of the adhesive layer can be configured to any value among 50°C, 55°C, 60°C, 65°C, 70°C, 75°C, 80°C, 85°C, 90°C, 95°C, and 100°C.

[0050] In some illustrative embodiments, the thickness of the adhesive layer can be configured to be greater than or equal to 20 μm and less than or equal to 30 μm. For example, the thickness of the adhesive layer can be configured to any value among 20 μm, 21 μm, 22 μm, 23 μm, 24 μm, 25 μm, 26 μm, 27 μm, 28 μm, 29 μm, and 30 μm.

[0051] In some illustrative embodiments, the material of the protective layer may include aluminized polyethylene terephthalate (aluminized PET).

[0052] In some illustrative embodiments, the melting point of the protective layer is greater than that of the adhesive layer. The melting point range of the protective layer is configured to be greater than or equal to 150°C. For example, the melting point of the protective layer can be configured to any value among 150°C, 151°C, 152°C, 153°C, 154°C, 155°C, 156°C, 157°C, 158°C, 159°C, 160°C, 161°C, 162°C, 163°C, 164°C, 165°C, 166°C, 167°C, 168°C, 169°C, and 170°C.

[0053] In some illustrative embodiments, the thickness of the protective layer can be configured to be greater than or equal to 20 μm and less than or equal to 30 μm. For example, the thickness of the protective layer can be configured to any value among 20 μm, 21 μm, 22 μm, 23 μm, 24 μm, 25 μm, 26 μm, 27 μm, 28 μm, 29 μm, and 30 μm.

[0054] During the heating and activation process, the inner layer temperature of the sealing film 12, Tinner, can reach Ts+5℃ to Ts+30℃, the outer layer temperature of the sealing film 12, Touter, is ≤Tm-20℃, and the end face temperature of the cigarette body is ≤60℃.

[0055] According to an embodiment of this application, the sealing film 12 further includes an intermediate layer. The intermediate layer is disposed between the adhesive layer and the protective layer. The intermediate layer may be loaded with menthol aroma substances or tobacco essential oils. The softening temperature of the intermediate layer is configured to be higher than that of the adhesive layer.

[0056] As an example, the intermediate layer is made of polypropylene with a thickness of 30 μm.

[0057] As an example, the material of the protective layer may include aluminized polyethylene terephthalate (PET) with a melting point Tm of 162°C and a thickness of 25 μm.

[0058] In some illustrative embodiments, the thickness of the intermediate layer can be configured to be greater than or equal to 25 μm and less than or equal to 35 μm. For example, the thickness of the intermediate layer can be configured to any value among 25 μm, 26 μm, 27 μm, 28 μm, 29 μm, 30 μm, 31 μm, 32 μm, 33 μm, 34 μm, and 35 μm.

[0059] In some illustrative embodiments, the total thickness of the sealing film 12 can be configured to be greater than or equal to 75 μm and less than or equal to 85 μm. For example, the total thickness of the seal can be configured to any value among 75 μm, 76 μm, 77 μm, 78 μm, 79 μm, 80 μm, 81 μm, 82 μm, 83 μm, 84 μm, and 85 μm.

[0060] According to an embodiment of this application, the sealing film 12 is circular, and the diameter of the sealing film 12 is greater than or equal to the outer diameter of the cigarette body 11. The portion of the edge of the sealing film 12 that extends beyond the insertion end is adhered to the outer wall of the cigarette body 11.

[0061] For example, the diameter of the sealing film 12 can be configured to be 7.22 mm, and the diameter of the cigarette body 11 can be configured to be 7.2 mm.

[0062] According to embodiments of this application, the heating method for heating the adhesive layer includes infrared radiation heating, wherein the radiation wavelength of the infrared radiation heating is configured to match the infrared absorption peak of the adhesive layer material.

[0063] As an example, the adhesive layer material may include EVA (VA content 22%), softening point temperature Ts = 65°C, thickness 25 μm, and infrared absorption peak at 3.4 μm. The radiation wavelength λ for infrared heating is configured to be 2.5 μm–8 μm.

[0064] In such an embodiment, the radiation wavelength of infrared radiation heating is configured to match the infrared absorption peak of the adhesive layer material. The adhesive layer has a much higher absorption rate of radiation energy in this band than the protective layer. Therefore, the infrared energy is mainly absorbed by the adhesive layer and converted into heat energy, so that the adhesive layer reaches the softening point temperature required for melting in a very short time (e.g., 0.02 to 0.3 seconds), while the protective layer does not heat up much because it absorbs less, thus preventing the protective layer from melting, shrinking or deforming due to overheating.

[0065] According to an embodiment of this application, the heating method for heating the adhesive layer includes hot air heating, wherein the hot air temperature is 100℃-150℃ and the hot air velocity is 5m / s-20m / s.

[0066] As an example, the hot air temperature for hot air heating can be any value among 100°C, 110°C, 120°C, 130°C, 140°C, and 150°C.

[0067] As an example, the hot air velocity can be any value among 5m / s, 6m / s, 7m / s, 8m / s, 9m / s, 10m / s, 11m / s, 12m / s, 13m / s, 14m / s, 15m / s, 16m / s, 17m / s, 18m / s, 19m / s, and 20m / s.

[0068] The heating device is a hot air heater, which includes a hot air nozzle and a temperature control system. The outlet width of the hot air nozzle is 2 mm - 5 mm, and the distance between it and the surface of the sealing film 12 (i.e., the surface of the adhesive layer away from the protective layer) is 1 mm - 3 mm.

[0069] In this embodiment, heating occurs before the sealing film 12 contacts the end face of the cigarette body, and the hot air device is spatially isolated from the cigarette body. Hot air at 100°C to 150°C directly impacts the adhesive layer surface of the sealing film 12 at a speed of 5 m / s to 20 m / s, forming strong and concentrated convective heat transfer, enabling the adhesive layer to be rapidly heated to above its softening point and melt in a very short time (e.g., 0.02 to 0.3 seconds). Simultaneously, because the heating time is extremely short and the heat source does not contact the cigarette body, heat will not be conducted through the sealing film 12 to the protective layer or further to the tobacco segment 113, avoiding problems such as outer layer melting and deformation, decreased moisture content of the tobacco, and loss of aroma components caused by contact-type overall heating in related technologies. According to embodiments of this application, the above-mentioned end-face sealing method further includes: cooling the cigarette body bonded to the sealing film 12 to accelerate the curing of the adhesive layer.

[0070] In some illustrative embodiments, the cooling method can be natural cooling.

[0071] In other illustrative embodiments, the cooling method may include forced air cooling, with a cooling time tcool ≥ 0.5 seconds, and the temperature of the adhesive layer drops to below Ts-20°C after cooling.

[0072] After the sealing film 12 is pressed against the end face of the cigarette body, the adhesive layer is still in a molten or softened state. If it is allowed to cool naturally, the curing time will be long, and the film may easily shift, wrinkle, or even fall off due to slight external force during subsequent transportation or handling, affecting the bonding quality. By using active cooling (such as forced air cooling), the heat in the pressing area can be quickly removed, allowing the adhesive layer to cool to below the softening point of the adhesive layer material in a short time (e.g., within 0.5 seconds), quickly completing the curing and shaping. This prevents the relative slippage of the sealing film 12 before it is fully cured, ensuring precise alignment and uniform bonding between the sealing film 12 and the end face of the cigarette body.

[0073] According to embodiments of this application, the above-described end-face sealing method further includes:

[0074] Check whether the overlapping area between the sealing film 12 and the end face is within the preset range;

[0075] If the overlapping area is not within the preset range, discard heated cigarettes with an overlapping area lower than the preset range.

[0076] In this embodiment, by detecting the actual overlap area between the sealing film 12 and the end face of the cigarette body online, defective products with insufficient bonding area due to misalignment, film deformation, or abnormal pressing can be detected in a timely manner. When the overlap area is lower than the preset range, the pneumatic rejection valve or robotic arm and other actuators can quickly separate the unqualified cigarette body from the production line to prevent it from flowing into the subsequent packaging or consumption stage, thus ensuring the sealing reliability of the products leaving the factory.

[0077] Figure 3 The diagram schematically illustrates the composition of the end-face sealing device 2 according to an embodiment of this application.

[0078] As another aspect of the embodiments of this application, an end-face sealing device 2 is provided for implementing any of the above-described end-face sealing methods. For example... Figure 3 As shown, the end-face sealing device 2 includes a conveying mechanism 21, a transporting mechanism 22, a heating mechanism 23, and a pressing mechanism 24. The conveying mechanism 21 is used to convey a substrate, which includes a laminated adhesive layer and a protective layer. The transporting mechanism 22 works in conjunction with the conveying mechanism 21 to cut the substrate into a sealing film 12 that matches the end-face shape of the cigarette body of the heated cigarette 1 during the conveying process. The heating mechanism 23 heats the sealing film 12 during the transporting process of the conveying mechanism 22, causing the adhesive layer to melt. The pressing mechanism 24 is used to convey the cigarette body and, during the conveying process, presses the end face of the tobacco segment 113 of the cigarette body against the molten adhesive layer to seal the end face.

[0079] During the pressing process, the coaxiality deviation between the center of the sealing film 12 and the center of the end face of the cigarette body is ≤0.3mm, and the parallelism deviation between the sealing film 12 and the end face of the cigarette body is ≤0.2mm.

[0080] In this embodiment, the conveying mechanism 21 continuously supplies a substrate with an adhesive layer and a protective layer. The conveying mechanism 22 directly cuts the sealing film 12 during its cooperation with the conveying mechanism 21, eliminating the need for separate cutting equipment or offline operation. The heating mechanism 23 heats the adhesive layer non-contactly during the conveying of the sealing film 12 by the conveying mechanism 22, so that the adhesive layer reaches a molten state before contacting the cigarette body, avoiding direct contact between the heat source and the cigarette body and eliminating the risk of heat damage to the tobacco segments 113. The pressing mechanism 24 presses the end face of the tobacco segments 113 against the molten sealing film 12 during the conveying of the cigarette body, achieving end face sealing. Compared to the online gluing solutions in related technologies that require applying glue first, then bonding, and then heating, the end-face sealing device 2 provided in this application internalizes the gluing function into the adhesive layer of the sealing film 12 itself, eliminating the need for complex glue insulation, conveying and coating components, reducing equipment maintenance costs. Heating and pressing are separated in time and space, and the pressing mechanism 24 does not need to withstand high temperature loads, resulting in a simpler structure and more stable operation.

[0081] According to embodiments of this application, such as Figure 3 As shown, the conveying mechanism 22 includes a conveying roller and a heat-insulating film. The conveying roller forms a plurality of negative pressure ports 221 evenly arranged along the circumference of the conveying roller. The heat-insulating film is disposed on the circumferential surface of the conveying roller and has through holes that match the plurality of negative pressure ports 221 to allow the sealing film 12 to be adsorbed by negative pressure.

[0082] In this embodiment, the cut, individually sealed film 12 is positioned at a predetermined position on the conveyor roller by negative pressure adsorption. During the rotation of the conveyor roller, it resists interference from centrifugal force and airflow, ensuring the positional stability and repeatability of the sealing film 12 during conveying, heating, and alignment stages. Since the heating mechanism 23 heats the sealing film 12 non-contactly during conveying (e.g., through infrared radiation or hot air), the adhesive layer temperature of the sealing film 12 can reach 50–100°C. If it directly contacts the metal roller, the heat will be rapidly dissipated by the roller, leading to a drop in adhesive layer temperature and insufficient activation. Simultaneously, the increased temperature of the metal roller may affect the lifespan of the negative pressure system seals or cause thermal deformation. The presence of the heat insulation film ensures that heat is primarily retained within the sealing film 12 and the adhesive layer, ensuring that the film remains in a sufficiently molten state when conveyed to the pressing station, thereby achieving stable and reliable bonding strength. Furthermore, the through-holes on the heat insulation film correspond one-to-one with the negative pressure ports 221, ensuring the effectiveness of negative pressure adsorption while minimizing the opening area of ​​the heat insulation film and maintaining the integrity of the heat insulation effect.

[0083] like Figure 3As shown, the conveying mechanism 21 includes a feeding roller 211 and a take-up roller 25. The substrate is wound around the feeding roller 211, and the take-up roller 25 is used to take up the remaining substrate scraps after cutting.

[0084] like Figure 3 As shown, the transmission mechanism 21 also includes a plurality of transmission rollers 212, which are arranged between the unloading roller 211 and the winding roller 25 along the transmission direction of the substrate, and are used to guide the substrate and maintain the substrate transmission tension stably.

[0085] As an example, the transmission mechanism 21 also includes a tensioning mechanism disposed on the transmission path of the substrate, which is suitable for keeping the substrate taut.

[0086] like Figure 3 As shown, the drive roller 212, which is tangentially arranged with the conveyor roller, has multiple circular cutters evenly distributed along its circumferential direction. The circular cutters are tangentially engaged with the circumferential surface of the conveyor roller to cut the substrate into circular sealing films 12 corresponding one-to-one with the negative pressure ports 221 when the substrate passes through the gap between the drive roller 212 and the conveyor roller. The circular cutters rotate synchronously with the drive roller 212, maintaining a precise positioning relationship with the negative pressure ports 221 on the surface of the conveyor roller. Each rotation completes a punching action at the corresponding negative pressure port 221, achieving high-speed continuous online cutting. At the same time, the cut circular films are immediately adsorbed by the negative pressure ports 221 on the conveyor roller, preventing the films from drifting or misaligning after cutting, thereby ensuring the positional accuracy between the films and subsequent pressing stations.

[0087] It should be understood that the embodiments disclosed herein are not limited to these. For example, a circular cutter can also be disposed on the conveyor roller and cooperate with the bottom roller on the drive roller for cutting; or, the cutting method can also be laser cutting, in which a laser beam scans a circular trajectory as the substrate passes through the conveyor roller, and the cut film is also adsorbed by the negative pressure port. In addition, the tangential cooperation between the drive roller and the conveyor roller is not limited to a one-to-one correspondence of circular cutters, and alternative solutions such as continuous die cutting and ultrasonic cutting can also be used.

[0088] Figure 4 A partially enlarged view of the transfer roller and the pressing roller according to an embodiment of this application is shown schematically.

[0089] According to embodiments of this application, such as Figure 4 As shown, the pressing mechanism 24 includes a pressing roller. The pressing roller forms a plurality of receiving grooves 241 that are recessed inward along the axial direction and correspond to the negative pressure port 221. The filter end of the cigarette body is inserted into the receiving groove 241 to expose the end face. During the rotation of the pressing roller, the end face is adhered to the sealing film 12.

[0090] After the adhesive layer adheres to the end face of the cigarette body, the adhesive force between the adhesive layer and the cigarette body is greater than the adsorption force of the negative pressure port on the conveying roller on the sealing film, causing the sealing film to move with the cigarette body and detach from the conveying roller.

[0091] As an example, each receiving groove 241 is provided with an elastic block. The elastic block is adapted to provide elastic force to the cigarette body in the radial direction of the pressing roller, so that the end face of the cigarette body protrudes from the outer surface of the pressing roller. When the pressing roller and the conveying roller meet, the end face of the cigarette body can first contact the heated and melted sealing film 12, while the outer surface of the pressing roller maintains a small gap with the sealing film 12. This avoids the pressing roller body directly squeezing the film, which would cause pressure dispersion or damage to the film. It ensures that the pressing pressure is concentrated between the end face of the cigarette body and the sealing film 12, improving the reliability of the bonding. The length of the tobacco section 113 or the filter section 111 of different cigarette bodies may have slight tolerances. The elastic force of the elastic block can adaptively compensate for the length difference, so that the end face of each cigarette body can remain convex and press with the sealing film 12 with basically consistent pressure. This avoids individual cigarette bodies being under-pressed or over-pressed and deformed due to fluctuations in the size of the cigarette body. In addition, the buffering effect of the elastic block can absorb the impact vibration generated during the pressing process, reduce the periodic impact load on the bearings of the pressing roller and the conveying roller, and help extend the service life of the equipment.

[0092] As an example, the pressing pressure P of the pressing roller is configured to be 0.1 MPa - 0.5 MPa, and the pressing time tpress is configured to be 0.1 seconds - 0.3 seconds. The surface temperature of the pressing roller is configured to Troll ≤ 40℃.

[0093] The difference in linear speed between the conveying roller and the pressing roller is ≤3%, and the gap between the conveying roller and the pressing roller at the composite station is 0.1mm-0.5mm.

[0094] In this embodiment, the receiving groove 241, through its enclosing positioning of the filter tip, ensures that the cigarette body maintains a stable posture and radial position during the high-speed rotation of the pressing roller. This prevents the cigarette body from shifting or falling off due to centrifugal force or vibration, ensuring that the end face of the tobacco segment 113 of each cigarette body meets the sealing film 12 with the same orientation and height. The receiving groove 241 corresponds one-to-one with the negative pressure port 221, enabling the pressing roller and the conveying roller to form a synchronous correspondence in spatial position. When the conveying roller delivers the heated sealing film 12 to the pressing station, the corresponding receiving groove 241 on the pressing roller precisely delivers the end face of the cigarette body to the same position. The coordinated rotation of the two rollers achieves automatic alignment and pressing of the film and the end face, eliminating the need for additional sensors or complex alignment adjustment mechanisms, simplifying the control system and improving operational reliability. Furthermore, the way in which the filter tip section 111 is inserted into the receiving groove 241 while the end face of the tobacco section 113 is exposed allows the pressing pressure to be applied directly between the end face of the cigarette body and the sealing film 12. The side wall of the receiving groove 241 also bears the radial component force generated during the pressing process, avoiding the direct transmission of pressure to the end of the filter tip, which could cause filter tip deformation or bending of the cigarette body, thus ensuring the appearance integrity and structural strength of the finished cigarette body.

[0095] According to an embodiment of this application, the heating mechanism 23 includes at least one infrared radiation lamp and a reflector. The infrared radiation lamp is adapted to emit infrared light toward the sealing film 12 being conveyed by the conveyor roller. The reflector is disposed on the side of the at least one infrared radiation lamp opposite to the sealing film 12 to focus the infrared light onto the sealing film 12.

[0096] According to an embodiment of this application, the reflector focuses infrared radiation onto the surface of the diaphragm, and the power P of the infrared radiation lamp... IR It is configured to be adjustable from 200W to 1000W.

[0097] The air outlet is configured to face the sealing film 12, so that high-temperature hot air (100℃~150℃) impacts the adhesive layer surface of the sealing film 12 vertically or at an angle at a set speed (5m / s~20m / s), forming local high-intensity convective heat transfer, thereby rapidly heating the adhesive layer to a molten state within a very short heating time (0.02~0.3 seconds).

[0098] In this embodiment, the reflector redirects the infrared energy radiated by the lamp tube away from the sealing film 12 back to the sealing film 12, effectively utilizing energy that might otherwise be lost. This improves the utilization efficiency of infrared radiation and allows for a higher heating rate at the same power, thus reducing equipment energy consumption. Through the focusing effect of the reflector (e.g., using a parabolic or elliptical reflector), the infrared light spot can be compressed and concentrated on the adhesive layer area of ​​the sealing film 12, significantly increasing the radiation energy density. This allows the adhesive layer to quickly reach the required melting temperature (e.g., 50–100°C) within a very short heating time (0.02–0.3 seconds), while avoiding unnecessary heat radiation to other areas of the conveyor roller and surrounding components. Furthermore, the reflector helps to make the radiation intensity distribution received on the surface of the sealing film 12 more uniform, reducing localized overheating or underheating caused by uneven lamp illumination or positional deviations. This ensures that the adhesive layer of each sealing film 12 reaches a consistent melting state before pressing, thereby improving the stability of the bonding strength and the product qualification rate.

[0099] The end-face sealing device 2 also includes at least one cold air nozzle, which is located downstream of the pressing mechanism. The cold air nozzle blows air towards the end face of the pressed cigarette body and in the opposite direction to the rotation of the pressing roller to avoid interfering with the normal operation of the pressing roller. The cold air temperature is configured to be 15℃~25℃, the cold air velocity is configured to be 10m / s~30m / s, and the cooling time is ≥0.5 seconds. After forced air cooling, the temperature of the adhesive layer drops to 20℃ below its softening point, completing the curing and shaping process.

[0100] The end-face sealing device 2 also includes an infrared thermometer and a first camera. The infrared thermometer is used to detect the surface temperature of the sealing film 12 after heating, and the first camera is used to detect the presence and position accuracy of the seal.

[0101] The end-face sealing device 2 also includes a rejection device, such as a pneumatic rejection valve.

[0102] The end-face sealing device 2 also includes a second camera, which is used to capture an image of the end face of the cigarette body after the sealing film 12 is combined with the end face of the cigarette body. The controller of the end-face sealing device 2 determines the overlapping area between the sealing film 12 and the end face based on the image. If the overlapping area is not within a preset range (for example, less than 90% of the total area of ​​the sealing film), the controller drives the rejection device to reject cigarette bodies with an overlapping area lower than the preset range.

[0103] In other illustrative embodiments, cigarette bodies with overlapping areas below a preset range can be manually removed by observation.

[0104] The cigarette body prepared according to the end-face sealing method and end-face sealing device 2 of the present application has no obvious thermal damage at the bonding interface between the sealing film 12 and the end face of the cigarette body, and the moisture content of the tobacco shreds 113 changes by ≤0.5%.

[0105] Example 1: Infrared radiation heating activation process

[0106] 1. Sealing film material 12

[0107] The three-layer composite sealing film 12 is used: the adhesive layer is EVA (VA content 22%), softening point temperature Ts=65℃, thickness 25μm, infrared absorption peak 3.4μm; the middle layer is made of polypropylene, thickness 30μm; the protective layer is made of aluminized PET (polyethylene terephthalate), melting point Tm=162℃, thickness 25μm.

[0108] 2. Equipment Configuration

[0109] Based on the modification of the roll-to-roll unit, a thermally activated composite unit was added: film cutting speed: 6000 pieces / minute; infrared radiation heater: power 500W, infrared lamp type: iodine tungsten lamp, main radiation wavelength 3-5μm, equipped with parabolic reflector; heating position: on the conveyor roller, heating zone arc length 10mm, corresponding to heating time 0.1 seconds (at a speed of 6000 pieces / minute); pressing device: silicone rubber pressure roller, hardness 60HA, pressing pressure 0.2MPa; cooling device: forced air cooling, cold air temperature 20℃, wind speed 15m / s, cooling time 0.6 seconds; infrared thermometer: online monitoring of the surface temperature of the film after heating.

[0110] 3. Process parameters are shown in Table 1:

[0111] Table 1

[0112]

[0113] 4. Composite effect

[0114] After 4 hours of continuous production, the test results are as follows: Bonding strength: 2.8±0.3N / 15mm; Alignment accuracy: 0.18±0.05mm; Change in tobacco moisture content: -0.3% (12.5% ​​before heating, 12.2% after lamination); Outer layer integrity rate: 100% (no melting or deformation); Pass rate: 99.7%.

[0115] Example 2: Hot air heating activation process

[0116] The difference between this embodiment and Embodiment 1 is that:

[0117] 1. Heating method

[0118] Hot air heating is used instead of infrared radiation heating: hot air temperature: 120℃; hot air speed: 12m / s; hot air nozzle width: 3mm, distance from the diaphragm: 2mm; heating time: 0.15 seconds (corresponding to a heating zone arc length of 15mm).

[0119] 2. Sealing film material 12

[0120] Adhesive layer: ternary copolymer polypropylene, softening point Ts=105℃, thickness 30μm.

[0121] Protective layer: homopolymer polypropylene, melting point Tm=165℃, thickness 25μm.

[0122] 3. Process parameters are shown in Table 2.

[0123] Table 2

[0124]

[0125] 4. Composite effect

[0126] Bonding strength: 3.1±0.2N / 15mm; Alignment accuracy: 0.20±0.05mm; Tobacco moisture content change: -0.2%; Pass rate: 99.5%.

[0127] Example 3: Study on the relationship between heating temperature and bond strength

[0128] Using the equipment and sealing film 12 of Example 1, the bonding strength was tested by changing the heating temperature, as shown in Table 3.

[0129] Table 3

[0130]

[0131] The results show that the optimal heating temperature is 80-90℃, at which point the bonding strength is ≥2.8N / 15mm, the outer layer is intact, and the temperature of the cigarette body end face is ≤55℃.

[0132] Example 4: Heating Time and Production Speed ​​Matching Test

[0133] At different production speeds, the length of the heating zone was adjusted, and the heating time was kept at 0.1 seconds. The composite effect was tested as shown in Table 4.

[0134] Table 4

[0135]

[0136] The results show that even at a high speed of 10,000 pieces / minute, good composite effects can still be obtained by increasing the length of the heating zone while keeping the heating time constant, proving the high-speed adaptability of this process.

[0137] Example 5: Temperature Closed-Loop Control Effect

[0138] Table 5 compares the temperature stability with and without infrared temperature feedback control.

[0139] Table 5

[0140]

[0141] Closed-loop control significantly improves temperature stability and product consistency.

[0142] Thermal damage assessment test:

[0143] GC-MS analysis was performed on tobacco shreds 113 before and after compounding to detect changes in volatile components (Figure 6).

[0144] Table 6

[0145]

[0146] The results show that the thermally activated composite process has minimal impact on the main components of tobacco and poses no risk of thermal damage.

[0147] The embodiments of this application have been described above. However, these embodiments are merely illustrative and not intended to limit the scope of this application. Although various embodiments have been described above, this does not mean that the measures in the various embodiments cannot be used advantageously in combination. The scope of this application is defined by the appended claims and their equivalents. Various substitutions and modifications can be made by those skilled in the art without departing from the scope of this application, and all such substitutions and modifications should fall within the scope of this application.

Claims

1. A method for sealing the end face of a heated cigarette, characterized in that, include: The substrate is cut to form a sealing film that matches the end face shape of the main body of the heated cigarette. The sealing film includes an adhesive layer and a protective layer stacked together. The adhesive layer is heated to melt it. The end face of the tobacco section of the formed cigarette body is facing the adhesive layer; The heated sealing film is pressed against the end face, so that the molten adhesive layer adheres to the end face.

2. The end-face sealing method according to claim 1, characterized in that, The heating method for heating the adhesive layer includes infrared radiation heating, wherein the radiation wavelength of the infrared radiation heating matches the infrared absorption peak of the adhesive layer material.

3. The end-face sealing method according to claim 1, characterized in that, The heating method for heating the adhesive layer includes hot air heating, wherein the hot air temperature is 100℃-150℃ and the hot air velocity is 5m / s-20m / s.

4. The end-face sealing method according to any one of claims 1-3, characterized in that, The melting point of the protective layer is higher than that of the adhesive layer.

5. The end-face sealing method according to claim 1, characterized in that, Also includes: The cigarette body bonded to the sealing film is cooled to accelerate the curing of the adhesive layer.

6. The end-face sealing method according to claim 1, characterized in that, Also includes: Detect whether the overlapping area between the sealing film and the end face is within a preset range; If the overlapping area is not within the preset range, heated cigarettes with an overlapping area lower than the preset range are rejected.

7. An end-face sealing device for implementing the end-face sealing method according to any one of claims 1-6, characterized in that, include: A transmission mechanism suitable for transmitting a substrate, the substrate comprising an adhesive layer and a protective layer stacked together; A conveying mechanism is adapted to cooperate with the transmission mechanism to cut the substrate into a sealing film that matches the end face shape of the heated cigarette body during the transmission process. A heating mechanism is used to heat the sealing film during the conveying process of the conveying mechanism, so as to melt the adhesive layer; The pressing mechanism is suitable for conveying the cigarette body and, during the conveying process, presses the end face of the tobacco section of the cigarette body against the molten adhesive layer to seal the end face.

8. The end-face sealing device according to claim 7, characterized in that, The conveying mechanism includes: The conveyor roller forms a plurality of negative pressure ports evenly arranged along the circumference of the conveyor roller; A heat-insulating film is disposed on the circumferential surface of the conveying roller, the heat-insulating film having through holes that match a plurality of negative pressure ports to adsorb the sealing film by negative pressure.

9. The end-face sealing device according to claim 8, characterized in that, The pressing mechanism includes: The pressing roller forms multiple receiving grooves that are recessed inward along the axial direction and correspond to the negative pressure port. The filter end of the cigarette body is inserted into the receiving groove to expose the end face. During the rotation of the pressing roller, the end face is bonded to the sealing film.

10. The end-face sealing device according to claim 8, characterized in that, The heating mechanism includes: At least one infrared radiation lamp is provided for emitting infrared light toward the sealing film being conveyed by the conveyor roller; A reflector is disposed on the side of at least one of the infrared radiation lamps facing away from the sealing film to focus the infrared light onto the sealing film.

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