Filter stick material

Abstract

The filter stick material is a cage type porous bar and comprises a wall material, and the wall material is of a hollow structure formed by fiber materials in a penetrating and interweaving mode. The filter stick material further comprises a hollow channel which is consistent with or parallel to the central axis of the wall material. The fiber material extends in a three-dimensional space, and a plurality of pore channels are formed among different fibers. The fiber materials are in a wave-like shape, and at least one fiber material extends spirally along the axis. The utility model further discloses a preparation method of the filter stick material. The filter stick material disclosed by the utility model has the characteristics of novel structure, low suction resistance, multiple pores, low smoke adsorption, good cooling effect and the like, and is simple in preparation process, high in production efficiency, low in cost, stable in product structure quality and very easy for industrial production.

Description

Technical Field

[0001] The utility model belongs to the field of cigarettes and relates to a filter rod and a preparation method thereof. Background Art

[0002] Optimizing the design of cigarette filter rods is one of the important means to control key indexes of cigarette smoke. Novel tobacco products (heat-not-burn tobacco) produce smoke through a mode of heating without burning. The amount of smoke is small and the smoke temperature is high (the highest temperature in the first three puffs exceeds 60°C). Therefore, corresponding requirements for low smoke interception, low suction resistance, and improved cooling effect are put forward for the filter rods.

[0003] Currently, some new filter rods have been developed at home and abroad, innovating the structure of the filter rods. Or achieving low suction resistance by adjusting the pores and their distribution of the filter rods, or embedding a section of hollow tube structure in the filter rods, or using porous fasteners. CN104203015 discloses a filter rod with an aerosol cooling unit, which is formed by longitudinally stacking folded polylactic acid films. When smoking a cigarette, with high-temperature smoke (which can exceed 150°C), significant thermal shrinkage deformation will occur to the continuous polylactic acid, and its safety needs to be verified. At the same time, its high surface area also increases smoke adsorption and reduces the smoking experience of consumers. CN115297740A and CN115297739A disclose a cooling element in which cooled external air enters a first tubular element through a ventilation area. The cooling effect of this structure on cigarette smoke is very limited, lacking a complex pore structure for effectively cooling the smoke.

[0004] By designing the special-shaped structure of the filter tip to change the smoke passage and increasing convective heat dissipation to achieve smoke cooling, CN201910502277.7 discloses an ultra-low adsorption type cooling function filter rod suitable for novel cigarettes. Inside the hollow core round tube of the filter rod, 2 to 6 layers of intercepting partitions are provided perpendicular to the axis direction. At least one throttling through hole is independently provided on each intercepting partition, achieving the purpose of low adsorption and temperature control. CN201820988160 and CN201820988243 also describe similar structures. Their porous fasteners are usually made of ceramics and polymers, with a porous structure in the center and a chamfered or grooved structure designed on the outer periphery. The structure is complex, generally processed by an injection molding process or produced intermittently, with high production costs, and the selected materials need to be verified in terms of safety.

[0005] In conventional cigarettes, in addition to conventional acetate fiber tow filter rods, using composite filter rods with added functional particles, hollow tubes, grooved filter rods and other multi-component filter rods, the purpose of changing the cigarette smoke flow channel can also be achieved by using special-shaped structural materials such as fasteners with different structures, but the preparation process has high requirements and high costs.

[0006] In summary, although the existing technologies can meet the requirements of "reducing draw resistance, low smoke interception" and / or temperature reduction for new tobacco products, they may have complex structures and inconvenient production, or be non-uniform filter media, or be of a segmented structure, with cumbersome preparation steps and high costs.

[0007] Therefore, there is an urgent need to develop a new type of filter rod structure suitable for new tobacco products (heat-not-burn cigarettes), which has a rich pore structure, can extend the flue gas flow path, and at the same time can regulate the pores to achieve a low flue gas contact area, can effectively reduce the flue gas temperature, and can also maintain a low flue gas interception of the flue gas concentration as much as possible to meet the cigarette smoking requirements. Summary of the Invention

[0008] Aiming at the above deficiencies of the existing technologies, the purpose of the present invention is to provide a cage-type filter rod material and its preparation method, which are prepared by weaving, dissolving, and drying at least two fiber materials (basic fiber and bonding fiber) with different solubility properties. The cigarette filter rod is applicable to new tobacco products (heated cigarettes) and has the characteristics of low flue gas interception, low draw resistance, and temperature reduction effect. The filter rod of the present invention has an innovative pore structure, permeable pores, and high stiffness, and the preparation method has low cost and simple production process, which is conducive to large-scale production.

[0009] The technical solution of the present invention to solve the above technical problems is:

[0010] A filter rod material, the filter rod material is a cage-type porous bar, including a wall material, and the wall material has a hollow structure formed by the interweaving of fiber materials.

[0011] Furthermore, the filter rod material further includes a hollow channel that is consistent or parallel with the central axis of the wall material.

[0012] Optionally, the fiber materials extend in three-dimensional space, and a number of pore channels are formed between different fiber yarn materials.

[0013] Optionally, the filter rod material is a cylindrical cage-type bar.

[0014] Optionally, the fiber materials are in a wave-like shape, and at least one wave-like fiber is arranged in a spiral along the axis, so that the cage-type bar can be formed by the interweaving of multiple wave-like fiber materials to generate non-linear, interconnected pore channels for the flue gas to flow through.

[0015] Optionally, compared with a planar fabric, the wave-like fiber materials have improved bending compressive strength.

[0016] Optionally, the wall material of the cage-type bar contains pore channels, which can be uniformly distributed or non-uniformly distributed on the wall material, corresponding to the arrangement direction of the wave-like fibers on the tubular wall material.

[0017] Optionally, the outer diameter of the cage-shaped rod is 4-9 mm, and the internal hollow channel is a single-diameter or variable-diameter channel with a pore diameter of 0.1-8.5 mm, preferably 0.5-4.5 mm.

[0018] Optionally, the overall filter rod material is in the shape of a rod, and its outer diameter can vary periodically, with a diameter of 0.5-9 mm, preferably 2-8 mm.

[0019] Optionally, the wall material thickness is 0.2-4 mm, and the wall pore porosity ratio is 10-90%.

[0020] Optionally, the hardness of the filter rod material is greater than 30%, preferably 60%-98%, preferably 80%-95%.

[0021] Optionally, the fiber material is a yarn, which is a long linear material and includes: at least one base fiber, which can be a fiber filament, staple fiber yarn, fancy yarn, polymer wire, metal wire; and / or at least one bonding material, which can be used as a shaping material and is distributed between and on the surface of the base fiber materials.

[0022] Optionally, the content of the bonding material (shaping material) is 0.1-95%, preferably 5-75%, preferably 15-45%; the base fiber is the remaining 100%.

[0023] Optionally, the base fiber includes, but is not limited to, cellulose, regenerated cellulose, cellulose ester, cellulose ether, any of their derivatives, starch-based thermoplastic resin, cellulose acetate, polylactic acid, chitosan, alginate, polyhydroxybutyrate, poly-ε-caprolactone, polyglycolic acid, polyhydroxyalkanoate, polypropylene, polyethylene, polyvinyl alcohol, polyester fiber, polyamide fiber, polyurethane, polyacrylonitrile, any one or more combinations of any of their derivatives, any of their copolymers, and any metal.

[0024] Optionally, the bonding material includes film-forming and bonding materials, including but not limited to cellulose acetate, polylactic acid, chitosan and its derivatives, cellulose derivatives, alginate, polyvinyl alcohol, polysaccharides, polyester, polyolefin, polyethylene glycol, or one or several of any of their derivatives.

[0025] Preferably, the bonding material is a soluble fiber dissolved in a certain dissolution medium, including but not limited to any one of acetate fiber, polylactic acid fiber, polyvinyl alcohol fiber, chitosan fiber, seaweed fiber, cellulose derivatives, and composite fibers of two or more of these materials.

[0026] Preferably, the bonding material is a water-soluble fiber, preferably including polyvinyl alcohol fiber, seaweed fiber, and carboxymethyl cellulose fiber.

[0027] The preparation method of the cage filter rod includes selecting a base fiber and a fiber-like bonding material (also known as a bonding fiber), and the base fiber and the bonding fiber have different dissolution properties. The cage rod is prepared by knitting, dissolving, and drying the base fiber and the bonding fiber; the dissolution herein refers to putting the intermediate product obtained by knitting into a dissolution medium and removing part or all of the bonding fiber through dissolution to obtain the cage rod.

[0028] It includes the following steps:

[0029] (1) Select a certain proportion of base fiber and bonding fiber to prepare at least two kinds of yarns, and the yarns are single-component fibers or multi-component fibers;

[0030] Optionally, the multi-component fiber yarn is obtained by doubling or sizing the base fiber and / or the bonding fiber to obtain a linear material.

[0031] Optionally, the multi-component fiber yarn is obtained by composite spinning of the base fiber material and / or the bonding fiber material to obtain a linear material.

[0032] Preferably, cellulose acetate is selected as the base fiber and the framework of the cage rod, and water-soluble polyvinyl alcohol is used as the bonding and shaping material and the pore-forming material.

[0033] Preferably, the base fiber is cellulose acetate filament or staple fiber yarn, with a fineness of 100-5000D and a weight percentage of 10-95%; the preferred bonding fiber is polyvinyl alcohol filament or staple fiber yarn, with a fineness of 100-5000D and a weight percentage of 90-5%.

[0034] (2) Wind different yarns on the spindles of a knitting machine for knitting to obtain a circular belt-shaped intermediate product;

[0035] The number of spindles of the knitting machine is 16-128 spindles, and the spindle number ratio of different yarns is 1:15-15:1. Preferably, the spindle number ratio of cellulose acetate yarn and polyvinyl alcohol yarn is 1:5-5:1.

[0036] The pore channels of the cage rod of the present utility model are related to the arrangement direction of the fiber yarns, and can be adjusted by selecting different knitting process parameters.

[0037] Optionally, when the spindle number ratio of cellulose acetate fiber and polyvinyl alcohol fiber is 1:1 and they are evenly arranged alternately, the channels are evenly distributed on the wall material of the cage rod obtained in the following step 3. When the spindle number ratio of cellulose acetate fiber and polyvinyl alcohol fiber is not 1:1, or they are not evenly arranged alternately, or the fineness of the fiber yarns is different, the pore channels of the wall material obtained in step (3) are unevenly distributed pore channels.

[0038] (3) Soak and dry the circular belt-shaped intermediate product obtained in step (2) in a certain dissolution medium, and dissolve part of the binder fibers to obtain a cage-shaped rod with a hollow structure in the tube wall and a stiffness meeting the requirements. Among them, the main body of the tube wall is the base fiber and the remaining binder fiber material as the shaping material.

[0039] Compared with the circular belt intermediate product (step 2) without the washing treatment in step (3), the two ends of the intermediate product are loose and cannot be slit and used in short lengths; it cannot maintain a stable circumference, is easily formed into a flat structure similar to a shoelace under the action of extrusion and stretching, etc., is not rod-shaped, and the structure in all directions is unstable, unable to meet the requirements of the cigarette tipping process.

[0040] Optionally, when polyvinyl alcohol fiber is selected as the binder material, the dissolution medium is water, and the circular belt-shaped intermediate product reaches partial dissolution of the binder fiber (polyvinyl alcohol fiber) and separation from the base fiber (acetate fiber) in water by one or several methods of static settlement, running water flushing, heating up, and ultrasonic wave.

[0041] Optionally, the circular belt-shaped intermediate product is statically settled in water at room temperature, the water temperature is uniformly raised to 40 - 100 °C within 0.5 - 30 min, after stopping heating, it is kept soaked for 1 - 60 min, and then taken out and dried, which can make the circular belt intermediate product shrink uniformly and approach the core material diameter inward, and the tube wall is more three-dimensional.

[0042] Optionally, the circular belt-shaped intermediate product is statically settled and soaked in water at room temperature for 0.5 - 30 min, then transferred to water at 40 - 100 °C for ultrasonic treatment for 1 - 15 min, the ultrasonic power is 20 - 60 KHz, the power is 200 W - 1000 W, and then taken out and dried.

[0043] Optionally, the circular belt-shaped intermediate product is statically settled and soaked in water at room temperature for 0.5 - 30 min, transferred to water at 40 - 100 °C for fixation and then subjected to running water flushing, the water flow rate is 1 - 10 m / s, the water temperature is 20 - 100 °C, the time is 1 - 30 min, and then taken out and dried. When performing running water washing and flushing, mechanical oscillation can be used simultaneously to improve the dissolution performance.

[0044] The cage-shaped rod needs to be dried by baking or natural drying after the dissolution process, so that the cage-shaped rod dries and hardens, the baking temperature is 40 - 120 °C, the baking time is 2 - 60 min, or it is naturally dried until completely hardened, and then the core rod is taken out.

[0045] Regarding the use and principle of the core rod:

[0046] Optionally, in steps (2) and (3), a braided core rod A and a soaking core rod B are used.

[0047] The diameter of the intermediate product of the round belt obtained by the knitting machine is directly related to the fineness of the yarn on the knitting machine spindles and the number of spindles. A larger yarn fineness and an increased number of spindles will increase the diameter of the cage bar.

[0048] During the knitting process in step (2), the function of the knitting mandrel A is to expand the intermediate product of the round belt to the required diameter through the filling of the mandrel A when it is difficult to directly prepare the intermediate product of the round belt with the required diameter due to the fineness of the yarn and the number of knitting spindles. By adjusting the diameter of the mandrel A, the diameter of the intermediate product of the round belt can be flexibly adjusted, which is more convenient than adjusting the number of knitting spindles and the fineness of the yarn.

[0049] Optionally, the diameter of the knitting mandrel A is 0.1 - 8.5 mm, and the material is a material with a smooth surface and certain compressive capacity, including but not limited to polytetrafluoroethylene, silica gel, wood, metal, etc.

[0050] Furthermore, in order to obtain a cylindrical bar with the required diameter and stability, a mandrel B is added during the washing process in step (3), that is, a core material B is added to the central cavity part of the round belt-shaped intermediate product. The functions of using the soaked mandrel B are as follows: First, it prevents the round belt intermediate product from shrinking excessively during soaking, and the diameter is reduced to less than the required value; second, it prevents uneven shrinkage and the round belt intermediate product from generating bad deformation, and the mandrel B can be shaped; third, it prevents the round belt intermediate product from deforming under operations such as water flow scouring and ultrasound; fourth, when transferring from the soaking environment to the drying environment, the round belt intermediate product is extremely easy to deform due to its own softening. Adding the mandrel B can prevent deformation during transfer and maintain the shape of the round belt intermediate product unchanged and uniform during drying.

[0051] The diameter of the soaked mandrel B is 10% - 100% of the cavity diameter of the round belt-shaped intermediate product obtained in step (2), and the core material is a material with a smooth surface, water-soluble resistance, and high-temperature resistance, including but not limited to polytetrafluoroethylene, silica gel, wood, metal, etc.

[0052] Optionally, after step (3), through an independent sizing process, a bonding and shaping material is infiltrated between and on the surface of the fibers to make the obtained cage bar maintain a certain cylindrical shape and structural stiffness. The bonding materials include but not limited to cellulose acetate, polylactic acid, chitosan and its derivatives, cellulose derivatives, alginate, polyvinyl alcohol, polysaccharides, polyesters, polyolefins, polyethylene glycol, flavoring agents, moisturizing agents, dyes, one or several of their arbitrary derivatives.

[0053] Optionally, a certain content of hot-melt fibers can be added in step (1). The hot-melt fibers are one or several mixtures of polyolefins, polyesters, polyamides, polyimides, polyacetals, cellulose esters, cellulose ethers, polysaccharide-based thermoplastic materials, their arbitrary derivatives, and any of their copolymers; the softening point of the hot-melt fibers is lower than that of other basic fibers and bonding fibers.

[0054] A round belt-shaped intermediate product containing heat-melting fibers is obtained through knitting in step (2); it is heated until the heat-melting fibers melt and is bonded and shaped on the surface of the round belt-shaped intermediate product; the round belt-shaped intermediate product is washed to obtain a cage-shaped bar with a porous structure and high stiffness.

[0055] Optionally, the content of the heat-melting fibers in the base fibers in step 2 is 5%-100%, preferably 15%-85%, while the content ratio of the base fibers to the bonding fibers remains unchanged, still 10%-95%:90%-5%; here, the bonding fibers can only play a pore-forming role, such as complete dissolution of polyvinyl alcohol. The heat-melting fibers can play a bonding role or can completely serve as the base framework fibers.

[0056] Optionally, any functional fibers are introduced into the yarn to obtain a bar with the desired pore characteristics and functional properties.

[0057] Application of any of the said filter rod materials in cigarettes and heated cigarettes.

[0058] Optionally, any of the said filter rod materials is encapsulated into an outer wrapping material to obtain a cigarette filter rod. The wrapping materials include but are not limited to cellulose paper, fabrics, non-woven fabrics, plastic sheets, ceramics, glass; preferably, the wrapping material is cigarette forming paper or transparent film.

[0059] Compared with the prior art, the present utility model has at least the following beneficial effects:

[0060] The present utility model provides a cigarette filter rod material with a cage shape having hollow through holes and a preparation method. This "hollowed-out" and stiff cage-shaped cigarette filter rod material is formed in one step through knitting and washing processes of fiber materials, which cannot be achieved in one step by other textile technologies and filter rod forming technologies. For example, the existing technology uses flat fabrics as filter rod materials and requires at least multiple process steps such as textile, and / or punching, and rolling into a rod, and the pores are relatively single, with low hardness and need other technologies for support. The cage-shaped cigarette bar of the present utility model has multi-level pores and is formed in one step, and has the characteristics of high production efficiency, low cost, and the product structure characteristics meeting the process requirements of cigarette filter rods, and is a new method for preparing economical cigarette filter rods.

[0061] The present utility model uses acetate fibers and water-soluble polyvinyl alcohol fibers as raw materials to form a cylindrical cage-shaped bar. The application forms of the fibers are diverse, including but not limited to fiber filaments, staple fiber yarns, single wire rods, etc. After the dissolution process, part of the bonding fibers (polyvinyl alcohol fibers) are dissolved, and the base framework fibers (acetate fibers) maintain the knitted form. At the same time, the remaining polyvinyl alcohol fibers provide adhesion as bonding materials after drying, adhere to the surface and intersection points of the acetate fibers, maintain the stability of the hollow cage structure, improve the stiffness of the cage-shaped bar, and make the processing process stable in all directions, not easily deformed, and not easily scattered.

[0062] The wall material of the cage-type filter rod is formed into a three-dimensional hollow structure by the interweaving of fiber materials with a wavy extension. The fiber materials with a wavy extension provide better bending compressive resistance, good hardness and elasticity, meeting the requirements of the cigarette tipping process. A number of pore channels on the wall of the cage-type rod are distributed in the large pores of the fiber yarns and the micropores between the fibers, forming a complex flue gas channel while reducing the suction resistance and increasing the contact area with the flue gas. By changing the wall thickness and pore properties, the suction resistance and the flue gas adsorption rate of the filter rod can be changed to meet the different requirements of traditional cigarettes and new heated cigarettes.

[0063] In the preparation method, a weaving technique is used to prepare a round belt-shaped material with a certain diameter for use as a cigarette filter tip. In the dissolution treatment, one or several methods such as static soaking, running water flushing, heating, and ultrasonic treatment are used to partially dissolve the soluble binder fibers (polyvinyl alcohol fibers). After drying, a hollow cage-type structure is produced. By changing the diameter of the mandrel, the diameter and wall thickness of the hollow round belt-shaped intermediate product can be flexibly adjusted to meet the actual requirements of cigarette filter rod materials.

[0064] The application of the cigarette filter rod of the present utility model in cigarettes and new heated cigarettes.

[0065] Compared with the existing products, the present utility model has the following advantages:

[0066] The cage-type structure of the present utility model is novel, changing the current situation of the flue gas flow of the traditional reticulated filter rod of two-acetate fiber tow and the conventional hollow tube. It has excellent low suction resistance and low flue gas interception effect. Moreover, the non-linear and interconnected three-dimensional pores distributed on the cage-type wall material are beneficial to the heat absorption and heat conduction of the flowing high-temperature flue gas, showing a good cooling effect. At the same time, the thermal deformation during the suction process is small, reducing the suction resistance of the hollow cage-type rod and the change in suction resistance before and after suction. The application of the present utility model in the conventional cigarette filter rod can replace the special-shaped hole structures of the hollow conduit and the grooved paper, providing a more effective air flow diversion effect, and providing effects such as reducing suction resistance, reducing tar, and visualization. The filter rod of the present utility model has a novel structure, rich pores, and good stiffness, meeting the requirements of the cigarette machine operation process. It can be continuous, and the production cost of cigarette tipping processing is low, suitable for large-scale industrial production. Description of the Drawings

[0067] Figure 1 It is a schematic structural view of an embodiment of the intermediate product of the cage-type rod of the present utility model before soaking;

[0068] Markings in the figure: 1-round belt-shaped intermediate product, 2-core material.

[0069] Figure 2 It is a schematic structural view of an embodiment of the intermediate product of the cage-type rod of the present utility model after filling the core material.

[0070] Figure 33D schematic diagram of the knitting structure of an embodiment of the cage-shaped rod of the present utility model.

[0071] Figure 4 It is a 3D schematic diagram of the radial cross-section of an embodiment of the cage-shaped rod of the present utility model.

[0072] Figure 5 It is a schematic diagram of the axial cross-section of an embodiment of the cage-shaped rod of the present utility model. Specific embodiments

[0073] A filter rod material of the present utility model can provide a new flue gas flow channel, which is prepared by knitting, dissolving, and drying at least two fiber yarns with different solubility properties. Among them, the soluble fiber material plays a role in pore formation and bonding and shaping, and the insoluble fiber material (basic fiber) serves as a skeleton. The size and distribution of its pore channels are mainly related to the weight ratio of the skeleton component and the pore-forming component, and the distribution of the pore-forming component. Moreover, the cylindrical appearance and hardness index of the new structure filter rod meet the requirements of cigarette machine processing such as filter rod compounding, tipping, and slitting. The preparation process is simple and can be industrialized.

[0074] The soluble material of the present utility model can be in the form of filament, staple fiber, wire, etc., and can be represented by polyvinyl alcohol fiber, polylactic acid fiber, cellulose acetate fiber, etc. The dissolution media for dissolution include water, acetone, acetic acid, ethanol, and their mixed solvents.

[0075] Preferably, cellulose acetate fiber (as the basic fiber) and polyvinyl alcohol fiber (as the bonding fiber) are used as raw materials, and water is used as the dissolution reagent, with high material safety.

[0076] Among them, the cage-shaped rod structure is affected by factors such as the weight of the basic material (cellulose acetate fiber), the weight of the pore-forming and bonding material (water-soluble polyvinyl alcohol fiber), the distribution of the number of spindles of the two materials on the knitting machine, and the dissolution process parameters (washing temperature, time, ultrasonic / water flow rate). Optionally, after the polyvinyl alcohol fiber is completely dissolved, an independent sizing and impregnation treatment is carried out to fix the structure of the knitted fabric, obtaining a porous cage-shaped rod and providing the required stiffness.

[0077] It should be particularly emphasized that: the drawings of the present utility model are for easy understanding and are schematic displays of the basic structure and principle of the present utility model. The scope of the present utility model is not limited to the structure shown in the drawings.

[0078] Figure 1 The figure shows a schematic diagram of the structure of an intermediate product of an embodiment of the cage-shaped rod before soaking. The circular belt-shaped intermediate product is a hollow cylindrical structure before soaking. The tube wall is woven with cellulose acetate fiber and polyvinyl alcohol fiber, and the central part is a cavity. At this time, the tube wall is woven tightly, only with tiny gaps generated by fiber weaving, the surface is relatively flat, the texture is soft and easy to deform, lacking stiffness, and the cross-section is easy to unravel after shearing.

[0079] Figure 2 Shown is a schematic structural diagram of an intermediate product of an embodiment of a cage-shaped rod after filling the core material before soaking. The core material smaller than the cavity diameter causes the polyvinyl alcohol fibers to dissolve, and then the acetate fibers shrink, resulting in a thickened hollow tube wall, increasing the three-dimensional degree of the smoke passage and the contact area with the smoke. After drying, the hollow cavity of the hollow cage-shaped round belt-shaped intermediate product has the same diameter as the core material.

[0080] Figure 3 Shown is a 3D schematic diagram of the braided structure of an embodiment of the cage-shaped rod of the present invention. It can be clearly seen from the figure that the wavy fiber material is arranged in a spiral along the axial direction; it can be seen from the figure that the polyvinyl alcohol fibers dissolve in water (playing a pore-forming role), and a hollow structure appears between the remaining acetate fibers. The residual polyvinyl alcohol bonds between and on the surface of the acetate fibers after drying (playing a bonding role), maintaining the stability of the hollow cage-shaped rod, providing stiffness, and facilitating processing and transportation. The hollow tube wall structure and the reduced central cavity increase the contact area between the smoke and the cooling structure, improving the cooling effect, making the draw resistance stable and appropriate, reducing smoke adsorption, and ensuring the smoke flavor.

[0081] Figure 4 Shown is a 3D schematic diagram of the radial cross-section of an embodiment of the cage-shaped rod. It can be seen from the figure that the acetate fibers are intertwined to form a tube wall part with a certain thickness on the cross-section, and there are uniformly distributed holes in the tube wall. There is a cavity in the center of the hollow cylindrical cage-shaped rod. Residual polyvinyl alcohol fibers can be seen attached to the surface and inside of the acetate fibers, making the cage structure stable and not deformed, and not falling apart after shearing.

[0082] Figure 5 Shown is a schematic diagram of the axial cross-section of an embodiment of the cage-shaped rod of the present invention. This structure is to Figure 3 The cage-shaped rod is extruded through a mold with different diameters to obtain a rod with a periodically changing outer diameter required by the design.

[0083] The porosity of the wall holes of the cage-shaped rod is measured by the water exclusion method to calculate the volume v1 of the fiber material of the porous wall material, the overall volume V0 of the cage wall is measured by the diameters of the inner core rod and the rod, and is calculated by the pore formula (V0 - V1) / V0 * 100%.

[0084] The hardness performance of the filter rod is determined with reference to GB / T 22838.6 - 2009.

[0085] The present invention is further described below in conjunction with specific embodiments.

[0086] Example 1

[0087] (1) Select acetate fiber (base fiber) with a fineness of 1100D and polyvinyl alcohol fiber (bonding fiber) with a fineness of 1100D.

[0088] (2) Use a knitting machine with 32 spindles (such as a 90 - series round rope single - head single - machine 32 - spindle high - speed knitting machine), with 16 spindles for acetate fiber and 16 spindles for polyvinyl alcohol fiber, and knit them into a hollow round - belt - shaped intermediate product. The ratio of acetate fiber to polyvinyl fiber is 50%:50%, and the corresponding spindle ratio is 1:1.

[0089] (3) Fill the hollow part of the round - belt - shaped intermediate product with a core material with a diameter of 4 mm. The initial soaking temperature is 15 °C, and it is heated uniformly or intermittently to 80 °C over 40 min.

[0090] (4) Dry the soaked round - belt - shaped intermediate product. The drying temperature is 60 °C, and the drying time is 40 min.

[0091] (5) Through the washing process, the water - soluble polyvinyl fiber forms pores while also retaining a certain bonding effect. After measurement, the obtained hollow cage - type rod has a diameter of 6.8 mm, a wall thickness of 1.4 mm, a wall porosity of 76%, a content ratio of acetate fiber (fibrous yarn) to polyvinyl alcohol (shaping material) of 70%:30%, and a hardness of 82%, meeting the requirements of the filter rod forming process.

[0092] Example 2

[0093] (1) Select acetate fiber with a fineness of 1100D and polyvinyl alcohol fiber with a fineness of 1100D. Combine and compound the acetate fiber and polyvinyl alcohol fiber, with a total fineness of 2200D; the polyvinyl alcohol fiber is combined in parallel, with a total fineness of 2200D.

[0094] (2) The number of knitting spindles is 32. The ratio of the number of spindles of the acetate / polyvinyl alcohol composite fiber to the number of spindles of the polyvinyl alcohol fiber after parallel combination is 1:1, and it is knitted into a hollow round - belt - shaped intermediate product, where the ratio of acetate fiber to polyvinyl alcohol fiber is 25%:75%.

[0095] (3) Fill the hollow part of the round - belt - shaped intermediate product with a core material with a diameter of 3 mm. The initial soaking temperature is 15 °C, and it is heated uniformly or intermittently to 80 °C over 40 min.

[0096] (4) Dry the soaked round - belt - shaped intermediate product. The drying temperature is 60 °C, and the drying time is 30 min.

[0097] (5) After measurement, the obtained hollow cage - type rod has a diameter of 6.8 mm, a wall thickness of 1.9 mm, a wall porosity of 75%, a content ratio of acetate fiber to polyvinyl alcohol of 65%:35%, and a hardness of 92%.

[0098] Control Example A: Compared with Example 2, the round belt intermediate obtained through Steps 1 and 2) was not subjected to the pore-forming washing and bonding and shaping treatment in Step 3). The two ends were loose, unable to maintain a stable circumference, and formed a flat structure similar to shoelaces under the action of extrusion, stretching, etc. It was not rod-shaped, and the anisotropic structure was unstable. The hardness was only about 30% according to the hardness test method for cigarette filters and could not be directly used for cigarette tipping.

[0099] Example 3

[0100] (1) Select acetate staple fiber yarn with a fineness of 1100D and polyvinyl alcohol staple fiber yarn with a fineness of 1100D, and combine and compound the acetate staple fiber yarn and the polyvinyl alcohol staple fiber yarn, with a total fineness of 2200D.

[0101] (2) The number of knitting spindles is 32, and the spindle number ratio of the acetate / polyvinyl alcohol composite staple fiber yarn to the polyvinyl alcohol staple fiber yarn is 1:1, and it is knitted into a hollow round belt-shaped intermediate, in which the acetate fiber and the polyvinyl alcohol fiber are 33%:67%.

[0102] (3) The hollow part of the round belt-shaped intermediate is filled with a core material with a diameter of 3 mm. Different from Example 1, the initial soaking temperature is 20°C, the soaking time is 30 min, and then it is transferred to water at 60°C and ultrasonically treated for 10 min, with an ultrasonic frequency of 40 KHz and a power of 550 W.

[0103] (4) The soaked round belt-shaped intermediate is subjected to a drying treatment, with a drying temperature of 60°C and a drying time of 30 min.

[0104] The obtained hollow cage-shaped rod has a diameter of 6.8 mm, a wall thickness of 1.9 mm, a wall porosity of 72%, a content ratio of acetate fiber to polyvinyl alcohol of 62%:38%, and a hardness of 93%.

[0105] Example 4

[0106] (1) Select acetate fiber with a fineness of 2200D and polyvinyl alcohol fiber with a fineness of 1100D.

[0107] (2) The number of knitting spindles is 32, and the spindle number ratio of acetate fiber to polyvinyl alcohol fiber is 1:1, and it is knitted into a hollow round belt-shaped intermediate, in which the ratio of acetate fiber and polyvinyl alcohol fiber is 67%:33%.

[0108] (3) The hollow part of the round belt-shaped intermediate is filled with a core material with a diameter of 4 mm. The initial soaking temperature is 20°C, the soaking time is 30 min, and then it is transferred and immersed in water at 80°C, fixed, and washed with running water for 20 min, with a washing speed of 2 m / s.

[0109] (4) The soaked round belt-shaped intermediate is subjected to a drying treatment, with a drying temperature of 60°C and a drying time of 30 min.

[0110] (5) After measurement, the obtained hollow cage-shaped bar has a diameter of 6.8 mm, a wall thickness of 1.4 mm, a porosity of the tube wall of 78%, a content ratio of cellulose acetate to polyvinyl alcohol of 75%:25%, and a hardness of 83%.

[0111] Example 5

[0112] (1) Select cellulose acetate with a fineness of 450 D and polyvinyl alcohol fiber with a fineness of 450 D.

[0113] (2) The number of knitting spindles is 32, and the ratio of the number of cellulose acetate spindles to the number of polyvinyl alcohol fiber spindles is 1:1. Knit into a hollow circular belt-shaped intermediate product, where the ratio of cellulose acetate and polyethylene fiber is 50%:50%.

[0114] (3) Fill the hollow part of the circular belt-shaped intermediate product with a core material with a diameter of 5 mm. The initial soaking temperature is 20 °C, the soaking time is 10 min, then transfer and immerse it in water at 60 °C, fix it and wash it with running water. The water flow rate is 1 m / s, and at the same time, turn on the ultrasound. The ultrasound frequency is 40 KHz, the power is 200 W, and soak for 15 min.

[0115] (4) The soaked circular belt-shaped intermediate product is dried. The drying temperature is 60 °C, and the drying time is 30 min.

[0116] (5) After measurement, the obtained hollow cage-shaped bar has a diameter of 6.8 mm, a wall thickness of 0.9 mm, a porosity of the tube wall of 80%, a content ratio of cellulose acetate to polyvinyl alcohol of 68%:32%, and a hardness of 79%.

[0117] Example 6

[0118] (1) Select cellulose acetate with a fineness of 2200 D and polyvinyl alcohol fiber with a fineness of 1100 D.

[0119] (2) The number of knitting spindles is 32, and the ratio of the number of cellulose acetate spindles to the number of polyvinyl alcohol spindles is 12:20. Knit into a hollow circular belt intermediate product, where the ratio of cellulose acetate and polyethylene fiber is 55%:45%.

[0120] (3) Fill the hollow part of the circular belt-shaped intermediate product with a core material with a diameter of 3 mm. The initial soaking temperature is 15 °C, and it takes 40 min to heat up to 80 °C.

[0121] (4) The soaked circular belt-shaped intermediate product is dried. The drying temperature is 60 °C, and the drying time is 30 min.

[0122] (5) After measurement, the hollow cage-shaped bar has a diameter of 6.8 mm, a wall thickness of 1.4 mm, a porosity of the tube wall of 84%, a content ratio of cellulose acetate to polyvinyl alcohol of 82%:18%, and a hardness of 58%.

[0123] Example 7

[0124] Referring to Example 2, the difference is that: the number of spindles of the acetic acid / polyvinyl alcohol composite fiber and the polyvinyl alcohol fiber is changed to 24:8. The weight ratio of the acetic acid fiber to the polyethylene fiber in the circular belt intermediate obtained by warp knitting is 37%:63%. After washing and drying, a cage-shaped bar with a diameter of 6.8 mm, a wall thickness of 1.4 mm, a wall porosity of 75%, a content ratio of acetic acid fiber to polyvinyl alcohol of 70%:30%, and a hardness of 75% is obtained.

[0125] Example 8

[0126] Referring to Example 2, the difference is that: the number of spindles of the acetic acid / polyvinyl alcohol composite fiber and the number of spindles of the polyvinyl alcohol fiber are changed to 30:2. The weight ratio of the acetic acid fiber to the polyethylene fiber in the circular belt intermediate obtained by warp knitting is 47%:53%. After washing and drying, a cage-shaped bar with a diameter of 6.8 mm, a wall thickness of 1.4 mm, a wall porosity of 64%, a content ratio of acetic acid fiber to polyvinyl alcohol of 75%:25%, and a hardness of 82% is obtained.

[0127] Example 9

[0128] (1) Select acetic acid fiber with a fineness of 1100 D and polyester hot-melt fiber with a fineness of 1100 D. The acetic acid fiber and the polyester fiber are combined and compounded, and the total fineness of 2200 D is used as the base fiber; the fineness of the polyvinyl alcohol fiber is 1100 D.

[0129] (2) The number of knitting spindles is 32. The ratio of the number of spindles of the acetic acid / polyester composite fiber to the number of spindles of the polyvinyl alcohol fiber is 1:1, and it is knitted into a hollow circular belt-shaped intermediate, in which the content ratio of the acetic acid fiber to the polyvinyl alcohol fiber is 50%:50%, and the content ratio of the acetic acid fiber to the polyester fiber is 50%:50%.

[0130] (3) The hollow part of the circular belt-shaped intermediate is filled with a core material with a diameter of 3 mm, and it is heated in an oven at a heating temperature of 140 °C and a heating time of 20 min. Subsequently, it is washed in a water bath. The initial soaking temperature is 15 °C, and it is uniformly or intermittently heated to 80 °C over 40 min. It is soaked at 80 °C and rinsed with running water under fixed conditions at a rinsing speed of 1 m / s for 60 min to ensure that all the polyvinyl alcohol is dissolved and detached from the circular belt-shaped intermediate.

[0131] (4) The soaked circular belt-shaped intermediate is dried at a drying temperature of 60 °C for 30 min.

[0132] (5) After measurement, the obtained hollow cage-shaped bar has a diameter of 6.5 mm, a wall thickness of 1.5 mm, a wall porosity of 42%, in which the content ratio of the acetic acid fiber to the polyester fiber is 50%:50%, the polyvinyl alcohol content is 0, and the hardness is 73%.

[0133] In this embodiment, polyester fiber is used as one of the basic fiber components, which plays a role in bonding and shaping through melting and serves as the basic framework in the cage-shaped strip; polyvinyl alcohol fiber is completely dissolved and only plays a role in pore formation.

[0134] Example 10

[0135] Referring to Example 9, the difference is as follows:

[0136] In Step 1, 122D polyester fiber is added to 1100D acetate fiber. In Step 2, the content ratio of acetate fiber to polyvinyl alcohol fiber in the obtained hollow round belt-shaped intermediate product is 50%:50%, and the content ratio of acetate fiber to polyester fiber is 90%:10%.

[0137] In Step 3, after the same heat treatment, the initial immersion temperature in the water bath is 15°C, and it is heated uniformly or intermittently to 80°C over 40 minutes for washing treatment.

[0138] The obtained cage-shaped strip has a diameter of 6.8 mm, a wall thickness of 1.9 mm, a wall porosity of 70%, a content ratio of acetate fiber to polyester fiber of 90%:10%, a content ratio of acetate fiber to polyvinyl alcohol of 70%:30%, and a hardness of 87%.

[0139] Example 11

[0140] Referring to Example 9, the difference is as follows:

[0141] 1) Select polyester fiber with a fineness of 1100D and ply it with polyvinyl alcohol fiber with a fineness of 1100D, with a total fineness of 2200D; the total fineness of polyvinyl alcohol fiber is 1100D.

[0142] 2) The content ratio of polyester fiber to polyvinyl alcohol fiber in the woven round belt-shaped intermediate product is 33%:67%.

[0143] 3) The hollow part of the round belt-shaped intermediate product is filled with a core material with a diameter of 3.5 mm, the heating temperature is 140°C, and the heating time is 30 minutes.

[0144] 4) In the water bath, the initial immersion temperature is 15°C, and it is heated uniformly or intermittently to 80°C over 40 minutes for washing treatment, and kept immersed at 80°C for 30 minutes.

[0145] 5) The soaked round belt-shaped intermediate product is dried, with a drying temperature of 90°C and a drying time of 30 minutes.

[0146] After measurement, the obtained hollow cage-shaped strip has a diameter of 6.2 mm, a wall thickness of 1.3 mm, a wall porosity of 56%, a content ratio of polyester fiber to polyvinyl alcohol of 90%:10%, and a hardness of 95%.

[0147] In this embodiment, polyester fiber is used as the base fiber, which plays a role in bonding and shaping after heating; polyvinyl alcohol fiber is used as the dissolution pore-forming material, and the residual polyvinyl alcohol is used as the bonding material to increase hardness.

[0148] Take the 17-mm hollow cage-shaped rods of Examples 1-5, and replace the polylactic acid film cooling section in the heated cartridge and the filter section of the traditional cigarette respectively. Use the self-built heated cigarette testing instrument to test and record the data, and compare with the performance of the polylactic acid thin film cooling section and the acetate fiber filter section. The results are shown in Table 1 and Table 2. The cage-shaped rod of the present invention has a small draw resistance. As the cooling section, it can effectively reduce the temperature of the cigarette smoke. The average smoke concentration is similar to that of the polylactic acid folded film cooling section, and is better than that of the acetate tow filter.

[0149] Table 1 Comparison of the performance test results of the cage-shaped filter rods of Examples 1-5 with the performance of the polylactic acid film filter rods

[0150] Sample Highest flue gas temperature / °C Maximum draw resistance / Pa Minimum draw resistance / Pa Average smoke concentration / % Polylactic acid 40.1 1445 909 72.1 Example 1 38.1 1100 826 71.7 Example 2 37.9 1090 800 71.9 Example 3 37.2 1035 776 72.3 Example 4 32.5 1145 930 68.8 Example 5 39.8 1017 805 72.7

[0151] Table 2 Comparison of the performance test results of the cage-shaped filter rods of Examples 1-5 with the performance of the acetate fiber tow filter rods

[0152]

[0153] At present, the new heated cigarettes on the market mainly use the longitudinal channel structure formed by the PLA folded film (for related content, see the published Chinese patent CN104203015B) as the cooling section of the heated cigarette. Add the 15-mm Example 2 to the heated cigarette as the cooling mouthpiece. According to the national standard GB / T19609-2004, use the Canadian deep draw mode (HCI) to detect the smoke temperature and release amount of the trial-produced cigarettes. The results are shown in Table 3.

[0154] Control group B: Replace the cooling section of Example 2 with a PLA film with a length of 15 mm, a porosity of 72%, and a thickness of about 35 mm (the related content is the same as that of the published Chinese patent CN104203015B).

[0155] It can be found that compared with the polylactic acid film cooling section, the nicotine release amount in the mainstream smoke of the heated cigarette using the cage-shaped filter rod of the present invention increased by about 20%, and the highest smoke temperature remained basically the same, without a significant increase due to the increase in the amount of smoke. This is mainly because the pore structure characteristics on the wall of the cage-shaped structure are conducive to heat transfer and reduce the interception of the smoke.

[0156] Table 3 Smoke data of the heated cigarettes using the cage-shaped rod and the polylactic acid film cooling section

[0157]

[0158] In summary, the cigarette filter rod prepared by the present utility model adopts a cage tube with hollow wall holes, which changes the arrangement mode of traditional diacetate fiber tow in the filter tip and the hollow tube. It has the characteristics of novel structure, low draw resistance, many pores, low flue gas adsorption, good cooling effect, etc. Moreover, the preparation process is simple, the production efficiency is high, the cost is low, and the product structure quality is stable, making it very easy to be industrially produced.

[0159] The above relevant descriptions and the descriptions of the embodiments are for the convenience of those of ordinary skill in the art to understand and apply the present utility model. It is obvious that those who are familiar with the technology in this field can easily make various modifications to these contents and apply the general principles described herein to other embodiments without creative labor. Therefore, the present utility model is not limited to the above relevant descriptions and the descriptions of the embodiments, and the improvements and modifications made by those skilled in the art according to the disclosure of the present utility model without departing from the scope of the present utility model should be within the protection scope of the present utility model.

Claims

1. A filter rod material, characterized in that: It comprises a wall material, wherein the filter rod material is a cage-type porous rod, and the wall material has a hollow structure formed by interlacing and interweaving fiber materials.

2. The filter rod material according to claim 1, characterized in that: The filter rod material further comprises a hollow channel which is consistent with or parallel to the central axis of the wall material.

3. The filter rod material according to claim 1, characterized in that: The fiber material extends in three-dimensional space, and a plurality of pore channels are formed between different fibers.

4. The filter rod material according to claim 1, characterized in that: The fiber material is in a wave-like shape, and at least one fiber material extends in a spiral shape along the axis.

5. The filter rod material according to claim 1, characterized in that: The wall material contains pore channels, including uniform and / or non-uniform channels.

6. The filter rod material according to claim 1, characterized in that: The filter rod material is cylindrical; and / or, its outer diameter is 4-9 mm; and / or, the hollow channel is a single diameter or a variable diameter channel, and the diameter of the hollow channel is 0.1-8.5 mm.

7. The filter rod material according to claim 6, characterized in that: The diameter of the hollow channel is 0.5-4.5 mm.

8. The filter rod material according to claim 1, characterized in that: The outer diameter of the filter rod material can be changed periodically, and the diameter is 0.5-9 mm.

9. The filter rod material according to claim 1, characterized in that: The diameter of the filter rod material is 2-8 mm.

10. The filter rod material according to claim 1, characterized in that: The wall material has a thickness of 0.2-4 mm and a wall porosity ratio of 10-90%.

11. The filter rod material according to claim 1, characterized in that: The hardness of the filter rod material is above 30%.

12. The filter rod material according to claim 1, characterized in that: The hardness of the filter rod material is 60-98%.

13. The filter rod material according to claim 1, characterized in that: The hardness of the filter rod material is 80-95%.

14. The filter rod material according to claim 1, characterized in that: The fiber material comprises at least one base fiber and at least one bonding material, wherein the bonding material is distributed between and on the surface of the base fibers.

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