Cooling filter material and filter for cigarettes

Abstract

The present application relates to the technical field of cigarette filter, in particular to a cooling filter material and a cigarette filter. The cooling filter material comprises a plurality of fiber units, the fiber units are arranged in parallel to form a bundle, and flow-through cavities are formed between adjacent fiber units; the fiber unit comprises a cooling filament, the cooling filament comprises a core layer and a cooling coating layer covering the core layer; the fiber unit further comprises a filter filament spirally wound on the cooling filament, and the surface of the cooling coating layer comprises a filter part covered by the filter filament and a cooling part between two adjacent filter parts. The fiber unit of the present application adopts a circumferential composite mode of the filter filament spirally wound on the cooling filament, so as to reduce the composite length while achieving the cooling and filtering effects, and further improve the suction resistance.

Description

Technical Field

[0001] This invention relates to the field of cigarette filter technology, to a cooling filter material and a cigarette filter, and more particularly to a cooling filter material and a cigar filter. Background Technology

[0002] Cigars are one of the most important tobacco products, ranking third after flue-cured and blended cigarettes. As a high-end tobacco product, cigars are loved by consumers for their unique smoking experience and rich flavor. However, in the middle and later stages of smoking, the higher temperature of the smoke can not only affect the original flavor of the cigar but also cause discomfort to the smoker's mouth and respiratory tract, thus affecting the tasting experience.

[0003] Although cigars and regular cigarettes differ slightly in combustion temperature, the methods for cooling cigars and regular cigarettes are essentially the same. Some methods involve using an external filter and incorporating cooling materials within the filter. For example, patent document CN111602845A discloses a cigarette cooling gel particle and its application. The cigarette filter rod includes two filter sections and a hollow cooling section sandwiched between the two filter sections, with the cigarette cooling gel particle added to the hollow cooling section. For example, patent document CN108903056A discloses a cigarette holder and a heated tobacco product: the cigarette holder includes a cooling section and a filter section. The cooling section includes tobacco leaves, which are used to cool and guide the smoke passing through the cooling section. The first end of the filter section is connected to the cooling section and is used to receive the cooled smoke and transfer it to the end of the cigarette holder away from the cooling section. The surface of the tobacco leaves is coated with a material with phase change function and / or moisturizing function. The material includes propylene glycol, glycerol, sorbitol, oligomaltitol, or thermotropic phase change gel.

[0004] It is evident that in existing technologies, whether cooling materials are used alone or coated on certain carriers, if the filter nozzle is to achieve both filtration and cooling effects simultaneously, the filtration section and the cooling section must always be combined in the axial direction. This results in a long filter nozzle, making it inconvenient to use and carry. On the other hand, reducing the length of the filter nozzle will result in insufficient filtration and cooling effects. Summary of the Invention

[0005] The present invention aims to solve the above-mentioned problems by providing a cooling filter material and a cigarette filter made from such a cooling filter material that is relatively short in length, easy to use and carry, while still having good cooling and filtering effects.

[0006] The technical solution to the problem solved by the present invention is as follows: First, a cooling filter material is provided, comprising a plurality of fiber units arranged in a bundle, with a flow cavity formed between adjacent fiber units; each fiber unit includes a cooling filament, the cooling filament including a core layer and a cooling coating covering the core layer; each fiber unit further includes a filter filament spirally wound on the cooling filament, such that the surface of the cooling coating includes a filter portion covered by the filter filament and a cooling portion located between two adjacent filter portions.

[0007] In this application, firstly, the material is composed of several fiber units bundled together, each fiber unit including cooling wire and filter wire to achieve cooling and filtration effects, and the material composed of a large number of fiber units bundled together has a more significant cooling and filtration effect.

[0008] Secondly, in each fiber unit, a cooling coating is provided on the surface of the cooling filament, so that the cooling coating area that the flue gas can contact is large, thereby improving the cooling effect; the filter filament is spiral-shaped, so that the filter filament area that the flue gas can contact is large, thereby improving the filtration effect.

[0009] Third, the filter wire is spirally wound around the cooling wire. On the one hand, this allows the surface of the fiber unit to functionally include alternating filtration and cooling sections. As the flue gas flows spirally along the filter wire, it is both filtered by the filter wire and cooled by the cooling coating of the cooling section, achieving simultaneous cooling and filtration effects. On the other hand, this also allows the surface of the fiber unit to structurally include relatively convex parts (filter wire surface) and relatively concave parts (cooling wire surface). The convex parts abut against adjacent fiber units, while the concave parts form cavities between them to allow flue gas to flow, reducing the material's suction resistance. Furthermore, because the filter wire and cooling wire are combined circumferentially, the length of the fiber unit is shorter than when the filter wire and cooling wire are combined axially. This allows for the production of relatively short filter tips, making them convenient to use and carry.

[0010] Based on this, this application provides a cooling filter material that, without increasing the axial length, has both good cooling and filtering effects, and also features low suction resistance.

[0011] In some embodiments of the cooling filter material, to further improve the simultaneous cooling and filtration effect, as a preferred embodiment of the present invention, the filter filament of one fiber unit abuts against the cooling portion of an adjacent fiber unit. This allows the flue gas to come into contact with the cooling portion of the adjacent fiber unit and achieve further cooling as it spirals along the filter filament of a certain fiber unit.

[0012] The method of forming the above structure is not limited. As a preferred embodiment of the present invention, the pitch of the spiral winding of the filter wire is controlled to be greater than the outer diameter of the filter wire. After aligning the ends of several fiber units, they can be directly merged so that most of the fiber units in the material meet the above structure without special alignment.

[0013] In the selection of cooling filter materials, for cooling wires, the cooling coating is the main part that plays a role in achieving the cooling effect. The material used for the cooling coating can be any commonly used cooling material in the existing technology, such as aerogel, hydrogel, phase change material, etc.

[0014] In some embodiments, to further improve the cooling effect, as a preferred embodiment of the present invention, the cooling coating comprises a hydrogel. The hydrogel material is a highly absorbent polymer that can rapidly absorb and lock in a large amount of water. After absorbing water and swelling, the hydrogel material has good thermal conductivity and water retention, effectively reducing the temperature of the flue gas passing through it.

[0015] The choice of hydrogel is not limited; for example, commonly used hydrogels in existing technologies such as polyacrylamide-sodium acrylate hydrogel, polyvinyl alcohol hydrogel, sodium alginate hydrogel, and cellulose hydrogel can be selected.

[0016] In some embodiments, to further improve the cooling effect of the material, as a preferred embodiment of the present invention, the gel layer comprises a heat-shrinkable thermosensitive hydrogel. A heat-shrinkable thermosensitive hydrogel refers to a gel whose volume shrinks with increasing temperature. Specifically, when the temperature rises, water molecules detach from the polymer chains due to the mutual attraction of hydrophobic groups, causing the gel volume to shrink. When applied in a cigarette filter, it encounters high-temperature smoke, causing the water molecules to detach and mix with the smoke to further enhance the cooling effect. Furthermore, due to the shrinkage of the gel volume, the outer diameter of the cooling wire decreases, thereby increasing the distance between adjacent fiber units to allow for smoke flow and improve suction resistance during inhalation. Moreover, for filter wires that may experience heat melting problems, the reduced outer diameter of the cooling wire can reduce adhesion and clogging issues between the filter wire and adjacent fiber units.

[0017] The choice of heat-shrinkable thermosensitive hydrogel is not limited. As a preferred option of the present invention, at least one of poly(N-isopropylacrylamide) hydrogel and poly(N-isopropylacrylamide / polyacrylic acid) hydrogel can be selected.

[0018] The core layer in the cooling fiber mainly serves to support the cooling coating. The choice of core layer is not limited. Fibers commonly used in cigarette filters in existing technologies can be selected, such as polypropylene fiber, polylactic acid fiber, acetate fiber, diacetate fiber, polyester fiber, carbon fiber, etc.

[0019] In embodiments using hydrogels, the core layer is preferably made of a material with low or no water absorption to ensure that the moisture in the hydrogel combines with the flue gas for cooling. Preferably, the core layer is selected from at least one of polypropylene fiber, polyester fiber, and carbon fiber.

[0020] The outer diameter of the core layer is not limited; the core layer can be a fine monofilament or a coarse filament bundled from several fine monofilaments. Coarse filaments can be used in the laboratory stage; fine monofilaments can be used in the mass production stage.

[0021] The preparation method of the cooling wire is not limited. In the embodiment where the cooling coating uses phase change material, the phase change material can be heated and melted and then applied to the core layer by brush or co-roller coating method; or the core layer can be immersed in the hot melt of phase change material for a period of time and then taken out.

[0022] In embodiments where a gel is used for the cooling coating, the core layer can be immersed in a precursor solution consisting of a gel monomer, a crosslinking agent, an initiator, and a solvent, and then the precursor polymerization reaction can be initiated; alternatively, an adhesive and a gel can be sequentially coated on the core layer.

[0023] The ratio of the core layer to the cooling coating should be limited. Excessive cooling coating may cause it to easily detach from the core layer, leading to blockage of the flow cavity; insufficient cooling coating may result in poor cooling effect. Preferably, the coating ratio of the cooling coating on the core layer is 0.1~1 g / cm³. 2 That is, the surface area is 1 cm² 2 A cooling coating of 0.1~1g can be applied to the core layer, specifically 0.1g, 0.2g, 0.3g, 0.4g, 0.5g, 0.6g, 0.7g, 0.8g, 0.9g, or 1g, preferably 0.5g.

[0024] The filter filament is the same as that of a traditional cigarette filter, and it performs the filtering function through adsorption. Therefore, the selection of the filter filament is basically the same as that of the materials used in traditional cigarette filters. As a preferred embodiment of the present invention, the filter filament is selected from at least one of polylactic acid fiber, cellulose acetate, cellulose diacetate, and polypropylene fiber.

[0025] The outer diameter of the filter filament is not limited. In some embodiments, to further improve suction resistance, as is preferred by the present invention, the outer diameter of the filter filament is not less than half the outer diameter of the cooling filament. A thicker filter filament allows for a larger distance between adjacent fiber units, enabling smoother flow of flue gas.

[0026] The preparation method of fiber units is not limited. In the laboratory stage, thicker cooling wires and filter wires can be wound together to obtain the units.

[0027] In the mass production stage, finer cooling and filter fibers can be used. The forming process of covered yarn in existing technologies can be referenced, such as using a covered yarn machine. The cooling fiber is fed parallel to the hollow spindle after passing through a drafting device. The filter fiber tube is then placed on the hollow spindle and rotated together. The unwinding of the filter fiber is also fed into the hollow spindle and moves downwards under the action of the suction pipe. Due to the rotation of the filter fiber tube, the filter fiber wraps around the cooling fiber with a twist once per rotation, forming a fiber unit. The pitch of the spiral winding is controlled by controlling the drafting speed of the cooling fiber or the rotation speed of the filter fiber tube.

[0028] Secondly, another objective of this invention is to provide a cigarette filter, comprising a housing having a cigarette inlet and a suction port, and the aforementioned cooling filter material, wherein the cooling filter material is filled within the housing, and the direction from the cigarette inlet to the suction port is parallel to the length direction of the cooling filter material.

[0029] In the cigarette filter of this application, only one material needs to be filled between the cigarette inlet and the suction port to achieve good cooling and filtration effects at the same time.

[0030] As a preferred embodiment of the present invention, the housing comprises, in sequence along the axial direction, an interface housing, a filling housing, and a suction port housing. The interface housing and the filling housing are detachably connected by a threaded structure, as are the filling housing and the suction port housing. This detachable connection facilitates the replacement of the interface housing to suit ordinary cigarettes or cigars; it also facilitates the replacement of the cooling filter material inside the filling housing.

[0031] In embodiments employing hydrogels, the hydrogel loses water after a period of use, affecting subsequent cooling effects; therefore, it is necessary to replenish the hydrogel with water. Preferably, the housing includes a filling portion for filling the cooling filter material and a replenishing portion for replenishing liquid to the cooling coating in the cooling filter material. The replenishing portion contains a liquid reservoir, and a liquid guide is provided between the liquid reservoir and the cooling filter material. The liquid reservoir can be filled with deionized water, tobacco flavoring, etc. Filling it with tobacco flavoring can further enhance the sensory experience of inhalation.

[0032] To improve the uniformity of fluid replenishment, as a preferred embodiment of the present invention, the housing includes an inner shell and an outer shell, the filling portion is formed inside the inner shell, and the fluid replenishment portion is formed between the inner shell and the outer shell.

[0033] The beneficial effects of this invention are: 1. This application provides a cooling filter material, which is composed of several fiber units. The fiber units adopt a circumferential composite method in which filter wires are spirally wound on cooling wires, so as to reduce the composite length while achieving cooling and filtration effects, and also improve the suction resistance.

[0034] 2. This application provides a cigarette filter tip made using the above-mentioned cooling filter material, which is relatively short in length, making it easy to use and carry, while still having good cooling and filtering effects. Attached Figure Description

[0035] Figure 1 This is a partial structural schematic diagram of the cooling filter material in Example 1; Figure 2 These are schematic diagrams of the cigarette filter tips in Examples 7 and 8; Figure 2 These are disassembly diagrams of the cigarette filter in Examples 7 and 8; In the figure: fiber unit 1, cooling wire 11, core layer 111, cooling coating 112, filter part 112a, cooling part 112b, filter wire 12, flow chamber 2, shell 3, smoke inlet 31, suction port 32, filling part 3a, liquid replenishment part 3b. Detailed Implementation

[0036] The following are specific embodiments of the present invention, and the technical solutions of the present invention will be further described, but the present invention is not limited to these embodiments. Example

[0037] A cooling filter material, such as Figure 1 As shown, the fiber unit comprises several fiber units 1 arranged in a bundle, with a flow cavity 2 formed between adjacent fiber units 1. Each fiber unit 1 includes a cooling filament 11, which includes a core layer 111 and a cooling coating 112 covering the core layer 111. The fiber unit 1 also includes filter filaments 12 spirally wound around the cooling filaments 11, such that the surface of the cooling coating 112 of the cooling filaments 11 includes a filter portion 112a covered by the filter filaments 12, and a cooling portion 112b located between two adjacent filter portions 112a. Furthermore, a portion of the filter filaments 12 of the fiber unit 1 corresponds to the cooling portion 112b of the adjacent fiber unit 1.

[0038] In this embodiment, the core layer 111 is made of polypropylene fiber; the cooling coating 112 is made of a phase change material composed of Na2HPO4·12H2O, urea, and CaSO4·2H2O; and the filter fiber 12 is made of cellulose acetate.

[0039] This cooling filter material is prepared through the following steps: Cooling filament: Prepare polypropylene fibers and bundle several polypropylene fibers into coarse polypropylene fibers with an outer diameter of 0.5 mm. Mix Na2HPO4·12H2O, urea, and CaSO4·2H2O in a mass ratio of 8:3:1 and melt at 60°C to obtain a mixed system, and maintain the heating and melting state. Control the coarse polypropylene fibers to pass through the mixed system at a speed of 0.05 m / s, and then send them into an air-cooling device to cool and crystallize, obtaining the cooling filament. By weighing the mass of the mixed system before and after use and calculating the mass difference, the amount of cooling coating used to coat the coarse polypropylene fibers can be obtained. In this embodiment, the total length of the coarse polypropylene fibers is 12 m (surface area of ​​2.355 cm²). 2 It uses a 1.2g cooling coating.

[0040] Filter fiber: Prepare cellulose acetate and bundle several cellulose acetate fibers into coarse cellulose acetate fibers with an outer diameter of 0.5 mm.

[0041] Fiber unit: The filter wire is spirally wound onto the cooling wire with a spiral pitch of 2mm, and then cut to a length of 30mm for each wire.

[0042] Cooling filter material: 400 fiber units are combined together and filled into a cylindrical tube with an inner diameter of 20mm to obtain cooling filter material. Example

[0043] This embodiment is basically the same as embodiment 1, except that the cooling coating uses polyvinyl alcohol / sodium alginate hydrogel.

[0044] This cooling filter material is prepared through the following steps: Cooling filament: Prepare polypropylene fibers and bundle several polypropylene fibers into coarse polypropylene fibers with an outer diameter of 0.5 mm and a length of 12 m. Dissolve 0.8 g of polyvinyl alcohol and 0.4 g of sodium alginate in 30 g of deionized water and stir evenly at 95 °C to obtain a transparent solution. Place the coarse polypropylene fibers evenly in the transparent solution, freeze at -20 °C for 24 h, thaw at room temperature for 2 h, and repeat this freeze-thaw process 3 times to obtain the cooling filament.

[0045] Filter fiber: Prepare cellulose acetate and bundle several cellulose acetate fibers into coarse cellulose acetate fibers with an outer diameter of 0.5 mm.

[0046] Fiber unit: The filter wire is spirally wound onto the cooling wire with a spiral pitch of 2mm, and then cut to a length of 30mm for each wire.

[0047] Cooling filter material: 400 fiber units are combined together and filled into a cylindrical tube with an inner diameter of 20mm to obtain cooling filter material. Example

[0048] This embodiment is basically the same as Embodiment 1, except that the cooling coating uses poly-N-isopropylacrylamide hydrogel.

[0049] This cooling filter material is prepared through the following steps: Cooling Fiber: Prepare polypropylene fibers by bundling several polypropylene fibers into coarse polypropylene fibers with an outer diameter of 0.5 mm and a length of 12 m. Add 1.2 g of N-isopropylacrylamide, 0.05 g of ammonium persulfate as an initiator, and 0.06 g of N,N'-methylenebisacrylamide as a crosslinking agent to 30 g of deionized water to obtain a precursor solution. Immerse the coarse polypropylene fibers in the precursor solution, mix and stir until no bubbles remain, and then seal to obtain a mixed system. Place the mixed system in a 60°C constant temperature water bath for 3 hours, and then remove the solid to obtain the cooling fiber.

[0050] Filter fiber: Prepare cellulose acetate and bundle several cellulose acetate fibers into coarse cellulose acetate fibers with an outer diameter of 0.5 mm.

[0051] Fiber unit: The filter wire is spirally wound onto the cooling wire with a spiral pitch of 2mm, and then cut to a length of 30mm for each wire.

[0052] Cooling filter material: 400 fiber units are combined together and filled into a cylindrical tube with an inner diameter of 20mm to obtain cooling filter material. Example

[0053] This embodiment is basically the same as embodiment 3, except that the preparation method of the cooling wire is different.

[0054] This cooling filter material is prepared through the following steps: Cooling filament: Prepare polypropylene fibers by bundling several polypropylene fibers into coarse polypropylene fibers with an outer diameter of 0.5 mm and a length of 12 m. Add 1.2 g of N-isopropylacrylamide, 0.05 g of ammonium persulfate as an initiator, and 0.06 g of N,N'-methylenebisacrylamide as a crosslinking agent to 5 g of deionized water to obtain a precursor solution. After reacting the precursor solution in a 60°C constant temperature water bath for 3 h, remove the solid to obtain a hydrogel. At 25°C, place the hydrogel in deionized water to absorb water, obtaining a transparent sol. Impregnate the coarse polypropylene fibers in the sol to obtain a mixed system. Then heat the mixed system to 40°C, and the hydrogel drains and solidifies to obtain a cooling filament. In this embodiment, because the hydrogel drainage operation is performed during the preparation process, it is necessary to replenish the liquid through a liquid bag when using it as a cigarette filter.

[0055] Filter fiber: Prepare cellulose acetate and bundle several cellulose acetate fibers into coarse cellulose acetate fibers with an outer diameter of 0.5 mm.

[0056] Fiber unit: The filter wire is spirally wound onto the cooling wire with a spiral pitch of 2mm, and then cut to a length of 30mm for each wire.

[0057] Cooling filter material: 400 fiber units are combined together and filled into a cylindrical tube with an inner diameter of 20mm to obtain cooling filter material. Example

[0058] This embodiment is basically the same as embodiment 3, except that the outer diameters of the cooling wire and the filter wire are different.

[0059] This cooling filter material is prepared through the following steps: Cooling Fiber: Prepare polypropylene fibers by bundling several polypropylene fibers into coarse polypropylene fibers with an outer diameter of 0.1 mm and a length of 300 m. Add 1.2 g of N-isopropylacrylamide, 0.05 g of ammonium persulfate as an initiator, and 0.06 g of N,N'-methylenebisacrylamide as a crosslinking agent to 30 g of deionized water to obtain a precursor solution. Immerse the coarse polypropylene fibers in the precursor solution, mix and stir until no bubbles remain, and then seal to obtain a mixed system. Place the mixed system in a 60°C constant temperature water bath for 3 hours, and then remove the solid to obtain the cooling fiber.

[0060] Filter fiber: Prepare cellulose acetate and bundle several cellulose acetate fibers into coarse cellulose acetate fibers with an outer diameter of 0.1 mm.

[0061] Fiber unit: The filter wire and cooling wire are sent to the textile mill, where a covering yarn machine is used to spirally wind the filter wire onto the cooling wire with a spiral pitch of 0.4mm, and then cut to a length of 30mm for each wire.

[0062] Cooling filter material: 10,000 fiber units are combined together and filled into a cylindrical tube with an inner diameter of 20 mm to obtain cooling filter material. Example

[0063] This embodiment is basically the same as embodiment 3, except that the core layer is made of polylactic acid fiber.

[0064] This cooling filter material is prepared through the following steps: Cooling Fiber: Prepare polylactic acid (PLA) fibers by bundling several PLA fibers into coarse PLA fibers with an outer diameter of 0.5 mm and a length of 12 m. Add 1.2 g of N-isopropylacrylamide, 0.05 g of ammonium persulfate as an initiator, and 0.06 g of N,N'-methylenebisacrylamide as a crosslinking agent to 30 g of deionized water to obtain a precursor solution. Immerse the coarse PLA fibers in the precursor solution, mix and stir until no bubbles remain, and then seal to obtain a mixed system. Place the mixed system in a 60°C constant temperature water bath for 3 hours, and then remove the solid to obtain the cooling fiber.

[0065] Filter fiber: Prepare cellulose acetate and bundle several cellulose acetate fibers into coarse cellulose acetate fibers with an outer diameter of 0.5 mm.

[0066] Fiber unit: The filter wire is spirally wound onto the cooling wire with a spiral pitch of 2mm, and then cut to a length of 30mm for each wire.

[0067] Cooling filter material: 400 fiber units are combined together and filled into a cylindrical tube with an inner diameter of 20mm to obtain cooling filter material. Example

[0068] A cigarette filter includes a cylindrical tube filled with cooling filter material as prepared in Example 1.

[0069] like Figure 2 and Figure 3 As shown, the cigarette filter includes a housing 3. The housing 3, along its axial direction, sequentially includes an interface housing, a filling housing, and a suction port housing. One end of the interface housing forms a cigarette inlet 31, and the other end is connected to the filling housing via a threaded structure. One end of the suction port housing forms a suction port 32, and the other end is connected to the filling housing via a threaded structure. The interface housing, filling housing, and suction port housing are sequentially connected to allow smoke to flow from the cigarette inlet 31 to the suction port 32.

[0070] The filling shell is filled with the cooling filter material prepared in Example 1. Specifically, the two ends of the cylindrical tube filled with the cooling filter material prepared in Example 1 are sealed with baffles, and several through holes are made on the baffles to allow flue gas to flow. During installation, the filling shell is first threadedly connected to the interface shell; then the cylindrical tube is inserted into the filling shell, with the axial direction of the cylindrical tube parallel to the axial direction of the shell 3; finally, the suction port shell is threadedly connected to the filling shell. Because the length direction of the fiber unit 1 is parallel to the axial direction of the cylindrical tube during the filling process, the length direction of the fiber unit 1 is parallel to the axial direction of the shell 3, that is, from the smoke interface 31 to the suction port 32.

[0071] When in use, insert a regular cigarette or cigar into the cigarette inlet 31 of the interface shell. After lighting the cigarette, the smoke enters the interface shell, passes through the through hole of the baffle plate into the cooling filter material, is cooled and filtered by the cooling filter material, and then flows out from the through hole of the baffle plate at the other end into the suction port shell, and is then inhaled by the user through the suction port 32. Example

[0072] This embodiment is basically the same as embodiment 7, except that: The cylindrical tube filled with cooling filter material was prepared using Example 4.

[0073] Second, such as Figure 2 and Figure 3 As shown, the filling shell includes a cylindrical portion (i.e., the outer shell) and two stop rings disposed within the cylindrical portion. When the cylindrical tube (i.e., the inner shell) from Embodiment 4 is inserted into the filling shell, the stop rings create an annular cavity between the filling shell, the two stop rings, and the outer wall of the cylindrical tube, which is the liquid replenishment section 3b. The filling shell also has an opening and a cover for sealing the opening, used to add liquid into the liquid replenishment section 3b. The cylindrical tube contains the filling section 3a, which is used to fill the cooling filter material.

[0074] To guide the liquid from the liquid tank into the cooling filter material, a liquid guide 33 is provided between the liquid tank and the cooling filter material. Specifically, the liquid guide 33 is a pipe with openings at both ends, and several openings are provided along the length of the pipe. A through hole is also provided on the cylindrical pipe. During installation, first, the filling shell and the interface shell are threaded together; then, the cylindrical pipe is inserted into the filling shell, and the cover of the filling shell is opened. One end of the pipe is inserted into the cooling filter material through the through hole of the cylindrical pipe, while the other end remains in the replenishment section 3b; then, the suction port shell is threaded together with the filling shell; finally, the liquid tank is placed into the replenishment section 3b, and the cover of the filling shell is closed. The pressure of the cover on the liquid tank causes the liquid tank to come into close contact with the end of the pipe, thus puncturing it. The liquid inside the tank can then flow along the pipe to the cooling filter material. Example

[0075] This embodiment is basically the same as embodiment 7, except that it uses the cylindrical tube filled with cooling filter material prepared in embodiment 2. Example

[0076] This embodiment is basically the same as embodiment 7, except that it uses the cylindrical tube filled with cooling filter material prepared in embodiment 3. Example

[0077] This embodiment is basically the same as embodiment 7, except that it uses the cylindrical tube filled with cooling filter material prepared in embodiment 5. Example

[0078] This embodiment is basically the same as embodiment 7, except that it uses the cylindrical tube filled with cooling filter material prepared in embodiment 6.

[0079] The blank example is basically the same as Example 7, except that an empty cylindrical tube is inserted into the filling shell.

[0080] Comparative Example 1 is basically the same as Example 7, except that the following material is inserted into the filling shell: This material is prepared by the following steps: Take the cooling wire and filter wire prepared in Example 1, cut the cooling wire and filter wire to a length of 30mm each, and directly combine 400 filter wires and 400 cooling wires into a bundle, and then fill it into a cylindrical tube with an inner diameter of 20mm to obtain the material.

[0081] Comparative Example 1 is basically the same as Example 7, except that the following material is inserted into the filling shell: This material is prepared by the following steps: Take the cooling wire and filter wire prepared in Example 1, cut the cooling wire and filter wire to a length of 30mm each, combine 400 filter wires into a bundle and fill them into a first cylindrical tube with an inner diameter of 5mm; combine 400 cooling wires into a bundle and fill them into a second cylindrical tube with an inner diameter of 5mm; insert the first cylindrical tube and the second cylindrical tube into the filling shell in sequence.

[0082] The cigarette filters obtained in Examples 7, 9-12, as well as the blank examples and comparative examples 1-2, were subjected to pressure drop tests in accordance with GB / T 22838.5-2009 Determination of physical properties of cigarettes and filter rods - Part 5: Cigarette draw resistance and filter rod pressure drop. The test results are shown in Table 1 below.

[0083] After attaching the tobacco filters obtained in Examples 7, 9-12, as well as the blank examples and comparative examples 1-2, to the same batch of cigars, a cooling and filtration test was performed: Temperature drop test: The temperature of the filter tip smoke inlet and the suction port were measured separately, and the temperature difference was calculated. The calculation results are shown in Table 1 below.

[0084] Filtration test: Install a Cambridge filter at the suction port, test the quality of the Cambridge filter before and after suction, and calculate the quality difference. The results are shown in Table 1 below.

[0085] Table 1.

[0086] As shown in Table 1, the greater the temperature difference between the cigarette inlet and the suction port, the better the cooling effect; the greater the mass difference of the Cambridge filter before and after suction at the suction port, the more unfiltered particulate matter there is, and the worse the filtration effect; the greater the pressure drop between the cigarette inlet and the suction port, the greater the suction resistance.

[0087] Comparing Example 7 with Comparative Examples 1 and 2, it can be seen that this application combines good cooling effect, filtration effect, and low suction resistance. This may be because, compared with Comparative Example 1, this application spirally winds the filter wire around the cooling wire, increasing the flue gas flow path and improving the contact time between the flue gas and the filter and cooling wires, thus resulting in better cooling and filtration effects. Simultaneously, the spiral winding creates an uneven surface on the fiber unit, and compared to the smooth surface of Comparative Example 1, the protruding filter wire in this application provides support between adjacent fiber units, preventing the flow cavity from collapsing and allowing for smooth flue gas flow, thus also providing a low suction resistance effect. In Comparative Example 2, because the cooling wire and filter wire are combined in the axial direction, the flue gas flow path is longer, resulting in a better cooling and filtration effect than this application. However, the longer path also leads to increased suction resistance, and its longer structure makes it inconvenient to use and carry.

[0088] Furthermore, comparisons within the embodiments revealed that the choice of cooling coating also has a certain impact on cooling, filtration, and suction resistance. Comparisons between Examples 7 and 9 show that using hydrogel can further improve the cooling and filtration effects. This may be related to the fact that the water in the hydrogel can assist in cooling, and the porous nature of the hydrogel itself can assist in filtration. Comparisons between Examples 9 and 10 show that, compared to ordinary hydrogels, heat-shrinkable thermosensitive hydrogels can further improve the cooling, filtration, and suction resistance. This may be because heat-shrinkable thermosensitive hydrogels release water more easily when heated, and after releasing more water, they have more pores, thus improving the cooling and filtration effects. Moreover, the volume of the heat-shrinkable thermosensitive hydrogel decreases after releasing water, increasing the spacing between adjacent fiber units, making it easier for flue gas to pass through, thereby further improving suction resistance.

[0089] Comparing Examples 10 and 11, it was found that the outer diameter of the filter wire and cooling wire also has a certain impact on cooling, filtration, and suction resistance. In Example 11, reducing the outer diameter of the filter wire and cooling wire can further improve the cooling and filtration effects. This may be because finer and more numerous fiber units provide more flow cavities, which can further disperse the flue gas for cooling and filtration; however, it will also lead to narrower flow cavities, which may result in increased suction resistance.

[0090] Comparing Examples 10 and 12, it was found that the choice of core layer also has a certain impact on cooling and filtration. In Example 12, polylactic acid (PLA) with relatively high water absorption was used as the core layer, which affected the contact between water in the hydrogel and flue gas, resulting in a reduced cooling effect; however, PLA has advantages over polypropylene in filtration, thus achieving a better filtration effect; in addition, although PLA usually has the problem of heat-melting blockage affecting suction resistance, in this application, PLA is only used as the core layer, so its impact on suction resistance is not significant.

[0091] The specific embodiments described herein are merely illustrative of the spirit of the invention. Those skilled in the art to which this invention pertains may make various modifications or additions to the described specific embodiments or use similar methods to substitute them, without departing from the spirit of the invention or exceeding the scope defined by the appended claims.

Claims

1. A cooling filter material, characterized in that: It includes several fiber units (1), the several fiber units (1) are arranged in a bundle, and a flow cavity (2) is formed between adjacent fiber units (1). The fiber unit (1) includes a cooling filament (11), which includes a core layer (111) and a cooling coating (112) covering the core layer (111). The fiber unit (1) further includes a filter filament (12) spirally wound on the cooling filament (11), such that the surface of the cooling coating (112) includes a filter portion (112a) covered by the filter filament (12) and a cooling portion (112b) located between two adjacent filter portions (112a).

2. The cooling filter material according to claim 1, characterized in that: The filter filament (12) of one of the fiber units (1) abuts against the cooling section (112b) of the adjacent fiber unit (1).

3. The cooling filter material according to claim 1, characterized in that: The cooling coating (112) comprises a hydrogel.

4. The cooling filter material according to claim 3, characterized in that: The hydrogel includes a heat-shrinkable thermosensitive hydrogel.

5. The cooling filter material according to claim 4, characterized in that: The heat-shrinkable thermosensitive hydrogel is selected from at least one of poly(N-isopropylacrylamide) hydrogel and poly(N-isopropylacrylamide / polyacrylic acid) hydrogel.

6. The cooling filter material according to claim 3, characterized in that: The core layer (111) is selected from at least one of polypropylene fiber, polyester fiber, and carbon fiber.

7. The cooling filter material according to claim 1, characterized in that: The filter fiber (12) is selected from at least one of polylactic acid fiber, cellulose acetate fiber, cellulose diacetate fiber, and polypropylene fiber.

8. A cigarette filter, comprising a housing (3) having a cigarette inlet (31) and a suction port (32), characterized in that: It also includes the cooling filter material as described in any one of claims 1 to 7, wherein the cooling filter material is filled inside the housing (3), and the direction from the smoke inlet (31) to the suction port (32) is parallel to the length direction of the cooling filter material.

9. A cigarette filter according to claim 8, characterized in that: The housing (3) includes a filling part (3a) for filling the cooling filter material and a replenishing part (3b) for replenishing liquid to the cooling coating (112) in the cooling filter material. The replenishing part (3b) is provided with a liquid bag, and a liquid guide (33) is provided between the liquid bag and the cooling filter material.

10. A cigarette filter according to claim 9, characterized in that: The housing (3) includes an inner shell and an outer shell, the filling part (3a) is formed inside the inner shell, and the liquid replenishment part (3b) is formed between the inner shell and the outer shell.

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