Filter stick for cigarette

Abstract

The invention discloses a cigarette filter stick which is made of a non-woven material, the non-woven material at least contains part of cellulose acetate fibers, and a plurality of grooves are formed in the surface of the non-woven material. The cigarette filter stick disclosed by the invention is processed and manufactured by using the non-woven material with a plurality of grooves on the surface, even if the non-woven material is composed of small deniers, the cigarette filter stick manufactured by using the non-woven material has smaller pressure drop and better smoking experience compared with a filter stick processed by directly using acetate fibers with small deniers. Therefore, the grooves formed in the surface of the non-woven material widen the limitation on the monofilament yarn density of the cellulose acetate fiber tow, and the cigarette filter stick meeting the smoking requirement can be manufactured even if cellulose acetate fibers with small denier number are used, that is, the specification requirement on the cellulose acetate fibers is reduced, and the production cost is reduced. And the range of acetate fiber products for processing cigarette filter sticks is expanded.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of cigarettes, and relates to a filter rod for cigarettes. BACKGROUND

[0002] At present, filter rods for cigarettes are mainly acetate fiber filter rods. Acetate fiber is non-toxic, odorless, impact-resistant, oil-resistant, non-static, has small suction resistance, strong adsorption, and good elasticity and thermal stability, and can selectively adsorb harmful components in smoke, thereby retaining certain nicotine without losing the taste of tobacco.

[0003] In order to manufacture acetate fiber filter rods, crimped acetate fiber tows must be opened (uncoiled), and the acetate fiber tows are formed into a dense network structure through the adhesion and solidification of a plasticizer.

[0004] Crimping refers to chemical, physical or mechanical crimping deformation processing of fibers, and imparting the fibers with a certain crimp, which can effectively improve the cohesiveness of acetate fiber and increase the bulkiness and elasticity of acetate fiber.

[0005] At present, the single filament linear density of acetate fiber used for processing filter rods is required to be 6.0 denier or more, and can be as high as 12.0 denier. If the single filament linear density of acetate fiber is selected to be 1.5-3.5 denier, the corresponding processing circumference is 16.00-17.00 mm, and the length of the filter rod is 120 mm, the pressure drop of the filter rod will be maintained at least at 7.0 kPa to 10.5 kPa. If the single filament linear density is 1.3 denier, or even acetate fiber tows with a single filament linear density of only 1.0 denier are used to process filter rods, the pressure drop of the filter rod will be further increased, resulting in difficulty in smoking cigarettes using the filter rod and poor smoking experience. In other words, acetate fiber tows with a single filament linear density of 1.0-3.5 denier cannot be used to process cigarette filter rods with a processing circumference of 16.00-17.00 mm, which undoubtedly limits the product range of acetate fiber tows that can be used. SUMMARY

[0006] The purpose of the present application is to provide a filter rod for cigarettes, expand the product range of acetate fiber that can be used, and reduce the requirements for the single filament linear density of acetate fiber and the like.

[0007] The purpose of the present application can be achieved by the following technical solutions.

[0008] A filter rod for cigarettes is made of non-woven material or fabric material, has a plurality of front and rear through holes, and at least part of acetate fiber is contained in the non-woven material or fabric material, and a plurality of grooves are formed on the surface of the non-woven material or fabric material, and the mass ratio of the acetate fiber is 1-100%.

[0009] Optionally, the non-woven material or fabric material further comprises hot-melt fibers or cotton fibers, and the mass ratio of the hot-melt fibers or cotton fibers is 0-99%; preferably, the mass ratio of the acetate fibers is 60-100%, and the mass ratio of the hot-melt fibers or cotton fibers is 0-40%; optionally, the hot-melt fibers comprise polylactic acid fibers.

[0010] Optionally, the linear density of the acetate fiber filaments is 1.0-12.0 denier, preferably 1.0-6.0 denier, and more preferably 1.0-3.5 denier.

[0011] Optionally, the product of the slitting width of the non-woven material and its thickness is 90%-200% of the cross-sectional area of the filter rod, preferably 95%-160%, and more preferably 100%-120%.

[0012] Optionally, the grammage of the non-woven material is 30-150 g / m2, preferably 35-80 g / m2, and more preferably 40-50 g / m2.

[0013] Optionally, the thickness of the non-woven material is 0.2-0.80 mm, preferably 0.31-0.40 mm.

[0014] Optionally, the longitudinal and transverse strength of the non-woven material is 60-80 N / 5 cm.

[0015] Optionally, the number of turns of the acetate fiber filaments is 13-26 turns per 25 mm, preferably 16-22 turns per 25 mm.

[0016] Optionally, the grooves are one of straight grooves extending along a straight line, curved grooves extending along an S-shaped curve, and zigzag grooves extending along a zigzag line.

[0017] Optionally, a plurality of parallel partition grooves are arranged in the middle of the grooves, and the partition grooves on adjacent two grooves are staggered.

[0018] Optionally, the surface of the non-woven material further comprises a plurality of diagonal grooves at an angle to the straight grooves.

[0019] Optionally, the cross-section of the non-woven material or fabric material with a plurality of grooves is wavy, the amplitude L of the grooves is 0.2-0.4 mm, and the distance T between two adjacent grooves is 0.5-1.0 mm.

[0020] Optionally, it is made by one or more of folding, winding, and gathering the non-woven material or fabric material.

[0021] Further, as an implementation direction, the non-woven material or fabric material in the filter rod of the present application is an acetate fiber non-woven fabric with a skeleton structure composed of two or more single filament linear densities of acetate fibers.

[0022] The acetate fiber non-woven fabric is composed of 100% acetate fibers.

[0023] Optionally, the filter rod has pores distributed in the acetate fiber non-woven fabric, with a porosity of 20%-96%, preferably 50%-96%, and more preferably 90%-96%.

[0024] Optionally, the filter rod is cylindrical, with a circumference of 14-28 mm and a diameter of 4.5-9 mm.

[0025] Optionally, the acetate fiber non-woven fabric is a three-dimensional arrangement of web structures with an area density and thickness, comprising several layers of thin fiber webs laid together, each layer of thin fiber web being formed by carding the fibers into a single fiber state, and having a surface containing fluff.

[0026] Optionally, the acetate fiber non-woven fabric has a grammage of 25-40 g / m 2 , preferably 30-40 g / m 2 .

[0027] Optionally, the acetate fiber non-woven fabric has a thickness of 0.05-0.80 mm, preferably 0.2-0.60 mm.

[0028] Further, the relatively thick acetate fibers provide support as a skeleton, and the relatively thin fibers have a large specific surface area to play an adsorption role.

[0029] Optionally, the relatively thin acetate fibers are 0.8-1.6 denier, with a mass percentage of 60%-80%; and the relatively thick acetate fibers are 2.0-8.0 denier, preferably 2.0-3.5 denier, with a mass percentage of 20%-40%.

[0030] Optionally, the acetate fibers have a length of 15-80 mm, preferably 30-60 mm.

[0031] Optionally, the acetate fibers have a crimp number of 8-30 per 25 mm, preferably 8-20 per 25 mm, and more preferably 8-15 per 25 mm.

[0032] Further, the preparation method of the acetate fiber non-woven fabric comprises the steps of carding, laying, and fixing the acetate fibers to produce the acetate fiber non-woven fabric.

[0033] Optionally, in the preparation method of the acetate fiber non-woven fabric, the mixing of acetate fibers with different single filament linear densities is performed at the spinning stage.

[0034] Optionally, the laying method of the cellulose acetate nonwoven fabric is straight laying and / or cross laying.

[0035] Optionally, the method for fixing the cellulose acetate nonwoven fabric includes, but is not limited to, one of the following methods or a combination of any two or more of the following methods: water jet method, hot rolling method, chemical bonding method, and seaming method.

[0036] In the method for preparing the cellulose acetate nonwoven fabric, the mixing of cellulose acetate fibers with different linear densities is performed in the spinning stage, and the cellulose acetate fibers with different linear densities are uniformly mixed.

[0037] Further, the wrapping material is a sheet material, including but not limited to cellulose paper, cellulose acetate film, and PET film; optionally, the thickness of the sheet material is not greater than 4 mm, preferably not greater than 2 mm, and preferably the thickness is 0.02-0.5 mm.

[0038] Optionally, the filter rod is formed into a porous structure by at least one of the following methods: folding, winding, and gathering, and the wrapping material is wrapped along the radial direction to form the porous structure.

[0039] The filter rod of any one of the above is applied in traditional cigarettes and heat-not-burn cigarettes.

[0040] As another implementation direction, the nonwoven material or fabric material comprises a high-density region and a low-density region.

[0041] In this implementation direction, the filter rod for cigarettes is in a cylindrical shape, with a circumference of 14-28 mm and a diameter of 4.5-9 mm; and / or, the hardness of the smoke filtration element is 66-80%, the suction resistance is 2000-8000 Pa, preferably 3800-7200 Pa, the suction resistance variation coefficient is 3-10%, preferably 5.8-9.6%, and more preferably 6.7-7.99%. Optionally, the nonwoven material or fabric material is made of a single fiber or a mixture of multiple component fibers; the fiber is a high molecular fiber, including but not limited to any one or a combination of multiple of the following: cellulose, regenerated cellulose, cellulose derivative, starch-based thermoplastic resin, cellulose acetate, polylactic acid, chitosan and its derivative, polyhydroxybutyric acid, poly-ε-caprolactone, polyglycolic acid, polyhydroxyalkanoate, polypropylene, polyethylene, polyvinyl alcohol, polyester, polyamide, polyurethane, and polyacrylonitrile.

[0042] Optionally, the nonwoven material or fabric material is a composite cellulose acetate nonwoven fabric made of cellulose acetate and other fibers.

[0043] Optionally, the mass percentage of cellulose acetate in the nonwoven material or fabric material is 0%-100%.

[0044] Optionally, the mass percentage of acetate fiber in the non-woven material or fabric material is 0, and the other fiber is 100% polylactic acid.

[0045] Optionally, the grammage of the non-woven material or fabric material is 30-80 g / m 2 , preferably 35-60 g / m 2 , and more preferably 40-50 g / m 2 .

[0046] Optionally, the longitudinal and transverse strength of the non-woven material or fabric material is 20-80 N / 5 cm, preferably 30-60 N / 5 cm, and more preferably 35-50 N / 5 cm.

[0047] Optionally, the density of the non-woven material or fabric material is 0.1-1.3 g / cm 3 , and the thickness is 0.05-0.5 mm, preferably 0.1-0.4 mm, and more preferably 0.2-0.3 mm.

[0048] Optionally, the high-density area plays a role in fixing the fiber web, stabilizing the structure, and enhancing the hardness; the density of the high-density area is ≤1.3 g / cm 3 , and the surface is flat and has no fluff structure; the density of the low-density area is ≥0.1 g / cm 3 , and the surface contains fluff structure; optionally, the shape of the high-density area structure can be, but is not limited to, one or a combination of circular, rectangular, square, diamond, diagonal, wavy, diagonal, and broken, and the area ratio is 5%-99% of the total area, preferably 5%-25%.

[0049] Optionally, the low-density area is a continuous structure, and the high-density area is composed of several independent parts dispersed in the low-density area; or the high-density area is a continuous structure, and the low-density area is composed of several independent parts dispersed in the high-density area.

[0050] Optionally, the linear density of the acetate fiber used to prepare the non-woven material or fabric material is 0.8-22.0 denier, preferably 1.0-6.0 denier, and more preferably 1.0-1.6 denier.

[0051] Optionally, the number of crimps of the acetate fiber used to prepare the non-woven material or fabric material is 8-30 / 25 mm, preferably 8-20 / 25 mm, and more preferably 8-15 / 25 mm.

[0052] Optionally, the length of the acetate fiber and the other fiber used to prepare the non-woven material or fabric material is 15 mm-80 mm.

[0053] Optionally, the cross section of the cellulose acetate fibers used to prepare the nonwoven or fabric material is circular, X-shaped or Y-shaped.

[0054] The method for preparing the nonwoven or fabric material used in the smoke filtering element comprises: preparing the composite cellulose acetate nonwoven fabric by hot rolling treatment of the fiber web to obtain the nonwoven or fabric material; the fiber web comprises the fiber web formed by direct carding and the nonwoven fabric formed after the fiber web is fixed by a solidification process such as water jet.

[0055] Optionally, the step of forming the fiber web by direct carding comprises mixing and opening the fibers before carding, uniformly mixing other fibers with different physical properties with the cellulose acetate fibers in proportion, and then carding the mixed fibers into a single fiber state, making the fibers into a thin fiber web state, and then stacking one layer of thin fiber web on another to increase the area density and thickness of the fiber web by the web laying process.

[0056] Optionally, the web laying process can be straight laying, cross laying, or a combination of straight laying and cross laying.

[0057] Optionally, the step of hot rolling treatment comprises the step of hot rolling the fiber web by two oppositely arranged rollers.

[0058] Optionally, one of the rollers is a metal roller, and the other is a metal roller, a rubber roller or a nylon roller.

[0059] Optionally, when the metal roller has patterns, the pressure and pressure intensity received by different parts of the fiber web are different, and the part of the fiber web in contact with the raised pattern part of the metal roller will be rolled into a (relatively) high density area, and the part of the fiber web in contact with the remaining part of the metal roller will be rolled into a (relatively) low density area, so that the fiber web after hot rolling treatment forms a nonwoven or fabric material with high density areas and low density areas; when the metal roller has no patterns, the pressure and pressure intensity received by different parts of the fiber web are basically the same, and after hot rolling treatment, the single density area accounts for 100% of the total area, in other words, a single density fiber web is formed; the high and low density of the fiber web can be set as needed, which is not described here.

[0060] Optionally, the surface temperature of the roller is 110-230℃, the rolling pressure is 0.01-4.5MPa, preferably 0.01-2.5MPa, more preferably 0.01-0.5MPa, and the roller speed is 10-45m / min.

[0061] In theory, the non-woven material or fabric material with uniform weight distribution and consistent thickness will have better stability of the suction resistance after being rolled into a filter rod. The conventional water-jet processed cellulose acetate non-woven fabric is difficult to achieve such a state, but it can be made close to such a state through other ways, such as hot calendering treatment which is an effective method. The water-jet processed cellulose acetate non-woven fabric is subjected to hot calendering by two oppositely arranged rollers, and the original thick places are thinned after roller pressing, so that the thickness of the cellulose acetate non-woven fabric is close to the front and back, i.e. the thickness variation coefficient is reduced, and the suction resistance stability of the filter rod is improved.

[0062] At the same time, the hot calendering treatment of the cellulose acetate non-woven fabric can improve the stiffness of the non-woven fabric, and further improve the hardness of the filter rod. For example, the 100% cellulose acetate non-woven fabric treated by the hot calendering treatment process of the present application is directly processed into a filter core with a circumference of 16.4 mm and a length of 120 mm by a filter rod forming machine, and the average suction resistance is measured to be 5900 Pa, the suction resistance variation coefficient is reduced from 16% to 9.6%, and the hardness is improved from 60% to 66%.

[0063] Further, the step of hot calendering treatment of the cellulose acetate non-woven fabric can be performed in the filter rod forming process. The step of hot calendering treatment is added in the filter rod forming process of the cellulose acetate non-woven fabric, which enriches the filter rod forming process of the cellulose acetate non-woven fabric, and the same cellulose acetate non-woven fabric can have different properties of the rolled filter rod due to the change of the process combination, which can bring a more abundant filter experience.

[0064] Generally, the filter rod of the present application can be cylindrical and can have any suitable dimensions. Preferably, the circumference of the filter rod of the present application is in the range of 15.8 mm to 31.4 mm; more preferably, the circumference is between 16.00 mm and 22.00 mm, more preferably between 16.20 mm and 16.80 mm.

[0065] The beneficial effects of the present application include:

[0066] The cigarette filter disclosed in the present application is manufactured using non-woven material or fabric material with grooved texture on the surface, even if the non-woven material or fabric material contains acetate fiber with small denier, the cigarette filter manufactured using the non-woven material has smaller pressure drop and better smoking experience compared with the filter manufactured directly using acetate fiber with small denier. The cigarette filter manufactured using non-woven material breaks through the limitation of product specification such as single filament linear density of acetate fiber when manufacturing filter using acetate fiber tow, and the grooved texture formed on the surface of non-woven material or fabric material ensures that the cigarette filter manufactured using the non-woven material also has good smoking experience, so even if acetate fiber with small denier is used, the cigarette filter with good smoking experience can be manufactured using non-woven material or fabric material with grooved texture on the surface. In short, the cigarette filter disclosed in the present application reduces the specification requirement of acetate fiber, and expands the product range of acetate fiber that can be used to manufacture cigarette filter.

[0067] On the other hand, the cigarette filter disclosed in the present application is manufactured using non-woven material or fabric material with grooved texture on the surface, so it has higher filling rate compared with the filter manufactured using acetate fiber tow, so that the cigarette filter has better ability to resist deformation and can better maintain the shape of the filter, and the through hole in front and back of the cigarette filter enables the cigarette filter to have good smoking experience even with high filling rate. BRIEF DESCRIPTION OF DRAWINGS

[0068] Figure 1 Comparison diagram of non-woven material with flat surface and non-woven material with multiple grooves on the surface.

[0069] Figure 2 Schematic diagram of cigarette filter rolled using non-woven material or fabric material with grooves disclosed in the present application.

[0070] Figure 3 Cross-sectional view of non-woven material or fabric material with grooves on the surface.

[0071] Figure 4 Non-woven material or fabric material with grooves extending along a straight line.

[0072] Figure 5 Non-woven material or fabric material with grooves extending along an S-shaped curve.

[0073] Figure 6 Non-woven material or fabric material with grooves extending along a broken line.

[0074] Figure 7 Non-woven material or fabric material with grooves and partition grooves.

[0075] Figure 8 A nonwoven or woven material provided with grooves and diagonal grooves.

[0076] Figure 9 A schematic side view of an acetate nonwoven fabric in one embodiment of the present application.

[0077] In the figure: 101. Higher line density acetate; 102. Lower line density acetate; 103. Acetate nonwoven fabric.

[0078] Figure 10 A schematic view of a hot calendering process for a nonwoven or woven material in another embodiment of the present application.

[0079] In the figure: 201. First calender roll; 202. Second calender roll; 203. Fibrous web; 204. Sheet material.

[0080] Figure 11 A schematic view of a nonwoven or woven material comprising high density regions and low density regions prepared in another embodiment of the present application.

[0081] In the figure: 301. High density region; 302. Low density region. DETAILED DESCRIPTION

[0082] The present application is further illustrated below in conjunction with the accompanying drawings and examples.

[0083] Acetate tow with monofilament line density of 1.0-3.5 denier, i.e. small denier acetate tow is processed to produce a filter rod for cigarettes as shown in Figure 2 The filter rod for cigarettes as shown in

[0084] In one exemplary embodiment, 1.3Y20000 acetate tow is used, and a KDF2 / AF2 filter rod forming machine is used to process the acetate tow to produce a filter rod with a circumference of 16.70 mm and a length of 120 mm. The filter rod has a weight of 0.38-0.39 g per rod, and no plasticizer is applied. The pressure drop of the filter rod is measured to be 9.89 kPa. In other words, the filter rod processed from acetate tow with 1.3 denier has a large pressure drop, resulting in a large resistance to draw of the cigarette and a poor smoking experience.

[0085] In order to ensure that the cigarette using the filter rod of small denier acetate tow has a good smoking experience, it is necessary to reduce the pressure drop value of the filter rod. One method to reduce the pressure drop of the filter rod is to provide one or more flow channels in the filter rod extending along the axial direction of the filter rod for the flow of smoke, so as to reduce the pressure drop of the filter rod.

[0086] Specifically, a stainless steel long needle with a diameter of 1.7 mm is inserted into the filter rod in the above-described exemplary embodiment along the axial direction, and the long needle is inserted into the filter rod for no less than three days, then the stainless steel long needle is withdrawn and the pressure drop of the filter rod is tested, the pressure drop of the filter rod is reduced to 8.81 kPa, because the through hole formed by the insertion of the long needle into the filter rod can serve as a flue gas passage, that is, flue gas can pass through the filter rod along the hole, thereby achieving a reduction in the pressure drop of the filter rod.

[0087] Finally, the filter rod is left to stand for one day, and the pressure drop of the filter rod is tested again and found to increase to 9.51 kPa, and observation of the end face of the filter rod shows that the hole formed by the penetration of the stainless steel long needle has been substantially closed, because the acetate fiber tows have resilience, and after the long needle is withdrawn, the acetate fiber tows that make up the filter rod rebound, and the hole is substantially closed.

[0088] Although the pressure drop of the filter rod can be reduced by providing a flow-through hole in the filter rod, the resilience of the acetate fiber tows makes it difficult for the flow-through hole to be maintained. If the acetate fiber tows also contain a plasticizer, it will be even more difficult to form a through hole in the formed filter rod. For example, a filter rod with a circumference of 17.20 mm, a length of 120 mm, and a pressure drop of 5.01 kPa is made using 6.0Y18000 acetate fiber containing a plasticizer. A stainless steel long needle with a diameter of 1.7 mm is inserted into the filter rod along the axial direction, and because the acetate fiber contains a plasticizer, the long needle is easily deflected during the penetration of the filter rod, making it difficult to form a through hole in the filter rod.

[0089] In short, the adhesion and solidification of the plasticizer can cause the acetate fiber to form a dense network structure, but such a network structure makes it difficult to form a through hole in the filter rod made using the acetate fiber.

[0090] Non-woven materials are processed using 1.0-3.5 denier acetate fiber tows as the main raw material, and the non-woven materials made using the processing methods of carding, needle punching, hydroentangling, and hot rolling have three-dimensional filter spaces. The filter rod made by rolling the non-woven material has an increased specific surface area for flue gas contact, which not only improves the filtration efficiency of flue gas, but also achieves reduced harm from smoking, and at the same time, the tensile strength of the non-woven material is enhanced, which also meets the requirements for longitudinal and transverse strength for subsequent processing into a filter rod. The rolled non-woven material filter rod can form a three-dimensional filter structure, but because the non-woven material naturally adheres together after rolling, it is still unable to form a through flow hole.

[0091] In order to avoid the non-woven material being rolled into filter rods and then being attached together, a plurality of continuous grooves are arranged on the surface of the non-woven material to form a groove texture. Due to the plurality of continuous grooves on the surface of the non-woven material, the non-woven material is difficult to be completely attached together, and a plurality of through holes are formed in the filter rod rolled by the non-woven material, and smoke can flow and diffuse along the through holes, so that the filter rod has a smaller pressure drop value.

[0092] In the present application, the end face of the filter rod close to the tobacco is referred to as the front end face, and the end face close to the oral cavity of the smoker is referred to as the rear end face, and thus the through hole refers to the hole extending from the front end face of the filter rod to the rear end face of the filter rod.

[0093] As shown in Figure 4 , the groove on the surface of the non-woven material is a straight groove, that is, the groove extends along the surface of the non-woven material in a straight line, and the extension direction of the groove is parallel to the length direction or the width direction of the non-woven material, or can extend along the diagonal direction of the non-woven material.

[0094] As shown in Figure 5 , the groove is a curved groove extending along a curve, that is, the shape of the groove on the surface of the non-woven material is approximately an S-shaped curve extending in a meandering manner.

[0095] As shown in Figure 6 , the groove is a fold line groove extending along a fold line, that is, the shape of the groove on the surface of the non-woven material is approximately a zigzag line formed by a plurality of line segments connected in sequence.

[0096] As shown in Figure 7 , in addition, a plurality of partition grooves parallel to each other can be arranged in the groove, and the partition grooves on two adjacent grooves are distributed in a staggered manner to enrich the groove texture of the non-woven material.

[0097] Similarly, referring to Figure 8 , on the basis of the groove texture of the Figure 4 , a plurality of diagonal grooves at an angle to the straight grooves are arranged on the surface of the non-woven material, and the diagonal grooves are parallel to each other.

[0098] It should be understood that the groove includes but is not limited to the shapes described above, Figures 4 to 8 the groove shapes shown in

[0099] Specifically, the groove can be manufactured on the non-woven material by rolling.

[0100] Further, the nonwoven material can be pressed by a heated roller to form stable through grooves on the surface of the nonwoven material. The surface temperature of the heated roller is 120-180 degrees Celsius.

[0101] As shown in Figure 1 , Figure 3 As shown in Figure 3 , the amplitude L of the groove is 0.2-0.4 mm, and the distance T between two adjacent grooves is 0.5-1.0 mm.

[0102] The width of the nonwoven material is reduced after the groove is pressed. The ratio of the reduced width of the nonwoven material to the width before pressing is defined as the crimp rate. The crimp rate of the nonwoven material with groove texture on the surface for processing filter rods is 7%-14%.

[0103] It should be noted that no plasticizer is added to the nonwoven material to avoid excessive resistance of the filter rod.

[0104] Taking a filter rod with a circumference of 16.70 mm as an example, the cross-sectional area of the filter rod is about 22.20 mm 2 If the thickness of the acetate fiber nonwoven is 0.35 mm, the slit width of the nonwoven material required can be calculated to be 63.40 mm. Considering the softness of the nonwoven material, the slit width of the nonwoven material can be appropriately increased, generally with an upper limit of 100%, and a lower limit of 90% to ensure the filtering effect of the smoke, so the slit width of the nonwoven material can be 57.06-126.80 mm; preferably, the slit width of the nonwoven material is 60.23-101.45 mm.

[0105] Preferably, the slit width of the nonwoven material is 63.40-76.08 mm.

[0106] The slit width of the nonwoven material is the width of the nonwoven material required to fill the cross-section of the filter rod, so the ratio of the product of the slit width of the nonwoven material and its thickness to the cross-sectional area of the filter rod can be approximately considered as the filling rate of the filter rod. The filling rate of the filter rod is 90%-200%, preferably 95%-160%, and more preferably 100%-120%.

[0107] Therefore, the filter rod for cigarettes made of the nonwoven material has a higher filling rate than the filter rod made directly from acetate fiber tows, so that the filter rod for cigarettes has better resistance to deformation and can better maintain the shape of the filter rod.

[0108] The non-woven material with grooves on the surface is processed by one or more of folding, winding, gathering, etc. to form a filter rod. For example, a filter rod with a circumference of 16.70 mm, according to the cutting formula, the cutting width can be selected from 57.06 to 126.80 mm, and for example, the preferred width is 63.40 to 76.08 mm, corresponding to at least 63 flow holes, and the position of the flow holes on the filter rod is random, and the diameter of the flow holes can be controlled by controlling the amplitude L and the distance T between adjacent grooves, thereby adjusting the smoking experience of the filter rod.

[0109] It should be understood that when the non-woven material with multiple grooves on the surface is processed into a filter rod for cigarettes by folding, winding, gathering, etc., the axial direction of the filter rod should be substantially the same as the extension direction of the grooves to ensure that the through holes are formed in the processed filter rod.

[0110] In addition to using non-woven materials with grooves on the surface to manufacture filter rods for cigarettes, continuous grooves can also be provided on polypropylene non-woven materials, and filter rods can be manufactured using polypropylene non-woven materials with grooves on the surface, which can also improve the problem of excessive pressure drop in small denier polypropylene fiber filter rods.

[0111] It should be noted that providing grooves on the surface of a small denier non-woven material can reduce the resistance of a cigarette filter rod made of the non-woven material and improve the smoking experience of the filter rod. Similarly, non-woven materials made of acetate fibers with a larger denier (3.5 to 22.0 denier) can also be used to roll filter rods, and if necessary, grooves can be provided on the surface of the non-woven material to improve the smoking experience of cigarettes.

[0112] The denier of the acetate fiber monofilament line in the non-woven material used to manufacture cigarette filter rods is 1.0 to 22.0 denier, preferably 1.0 to 12.0 denier, more preferably 1.0 to 6.0 denier, and more preferably 1.0 to 3.5 denier.

[0113] The grammage of the non-woven material is in the range of 30 to 150 g / m 2 , preferably 35 to 80 g / m 2 , and more preferably 40 to 50 g / m 2 .

[0114] The thickness of the non-woven material is in the range of 0.06 to 1.00 mm, preferably 0.2 to 0.80 mm, preferably 0.31 to 0.40 mm, and more preferably the thickness is 0.35 to 0.37 mm.

[0115] To improve the performance of the nonwoven material, so that the filter rod rolled by the nonwoven material has a better smoking experience, it is also necessary to further adjust the breaking strength of the nonwoven material. Specifically, it is necessary to improve the transverse strength of the nonwoven material, so that the longitudinal and transverse strengths are close, and the longitudinal and transverse strengths and are 60-80 N / 5 cm. The nonwoven material with close longitudinal and transverse strengths is easy to press grooves.

[0116] Further, reducing the crimp number of the acetate fiber tow (from 26-30 to 10-30 per 25 mm, 13-26 per 25 mm, preferably 16-22 per 25 mm) can also make it easier to form grooves on the surface of the nonwoven material.

[0117] Further, no plasticizer is applied to the acetate fiber, and the adhesion and solidification of the plasticizer can affect the groove formation on the nonwoven material. On the other hand, not applying a plasticizer can also make the nonwoven material more degradable.

[0118] The nonwoven material is mainly made of acetate fiber tow. Specifically, the nonwoven material can be entirely composed of acetate fiber tow, that is, the nonwoven material is 100% composed of acetate fiber.

[0119] The nonwoven material can also be a composite material composed of acetate fiber and hot melt fiber, or acetate fiber and non-hot melt fiber. Among them, the hot melt fiber includes but is not limited to polylactic acid fiber.

[0120] Further, a fabric material can also be used to manufacture a filter rod for cigarettes. In an alternative embodiment, the fabric material is composed of acetate fiber and cotton fiber, and the surface of the fabric material is also formed with groove textures by hot rolling or other suitable means. The filter rod for cigarettes processed by the fabric material has a significantly improved filling rate compared to the traditional cigarette filter rod, has stronger deformation resistance, and also has a good smoking experience.

[0121] Correspondingly, the surface of the fabric material is also formed with groove textures as shown in Figures 4 to 8 .

[0122] In one embodiment, the side view cross-sectional schematic diagram of the nonwoven material or fabric material prepared by the present application is as shown in Figure 9As shown in the figure, the non-woven material or fabric material is composed of relatively thin cellulose acetate fibers 1 and relatively thick cellulose acetate fibers 2, which are mixed and randomly distributed. The thicker the relatively thick cellulose acetate fibers 2 (the higher the linear density of the monofilament), the stronger the rigidity, which forms a skeleton in the non-woven material or fabric material and provides support for the relatively thin cellulose acetate fibers 1; the relatively thin cellulose acetate fibers 1 have a large specific surface area and can better play the adsorption role under the cooperation of the relatively thick cellulose acetate fibers 2.

[0123] In another implementation direction, one implementation of the sheet material is as follows Figure 11 As shown in the figure, the sheet material includes a plurality of circular high-density regions 301 and low-density regions 302, wherein the low-density regions 302 are a continuous structure, and a plurality of independent circular high-density regions 301 are dispersed in the low-density regions 302; in other embodiments, the high-density regions can also be a continuous structure, and the low-density regions can be composed of a plurality of independent parts dispersed in the high-density regions; at the same time, the shape of the independent high-density regions or low-density regions can be any pattern or texture, including but not limited to one or a combination of circular, rectangular, square, diamond, herringbone, wavy, diagonal, and broken lines, and the area ratio is 5%-99% of the total area, preferably 5%-25%. The high-density regions play a role in fixing the fiber web, stabilizing the structure, and enhancing the hardness; the density of the high-density regions is ≤1.3 g / cm 3 , and the surface is smooth and has no fluff structure; the density of the low-density regions is ≥0.1 g / cm 3 , and the surface contains a fluff structure.

[0124] The fiber web is subjected to hot rolling treatment to prepare a composite cellulose acetate non-woven fabric to obtain the sheet material, and the fiber web includes a fiber web formed by direct carding and a non-woven fabric formed after solidification of the fiber web, such as water jet.

[0125] The hot rolling treatment is, for example Figure 10 As shown in the figure, the fiber web 203 is subjected to hot rolling by two first rollers 201 and second rollers 202 oppositely arranged and rotating towards each other to obtain the sheet material 204 which can be used to prepare a flue gas filtering element.

[0126] One of the first rollers 201 and the second rollers 202 is a metal roller, and the other is a metal roller, a rubber roller, or a nylon roller. The metal roller is provided with a pattern or texture, and the fiber web is subjected to hot rolling treatment to form a sheet material having high-density regions and low-density regions.

[0127] Further, in Figure 10In the shown embodiment, the first roller 201 rotates clockwise, the second roller 202 rotates counterclockwise, and the fiber web 203 moves from left to right, is rolled between the first roller 201 and the second roller 202, and then is rolled to form the sheet material 204. Since the fiber web 203 and the first roller 201 and the second roller 202 move in opposite directions at the contact points, the sheet material 204 can be stretched by a winding device to overcome the force of the first roller 201 and the second roller 202 and continue to move from left to right.

[0128] Embodiment 1

[0129] The nonwoven material used for processing the filter rod is composed of acetate fibers and polylactic acid fibers, wherein the single-fiber linear density of the acetate fibers is 1.3 denier, and the mass ratio of the acetate fibers is 80%; the single-fiber linear density of the polylactic acid fibers is 1.56 denier, and the mass ratio of the polylactic acid fibers is 20%. In this embodiment, the nonwoven material is processed by using the straight-laid method. The nonwoven material has a longitudinal strength close to a transverse strength, a longitudinal-transverse strength sum of 60-80 N / 5 cm, a crimp number of 10-30 per 25 mm, a thickness of the straight-laid web of 0.35 mm, a grammage of 45±5 g / m 2 , and a slitting width of 67 mm. The amplitude L of the grooves formed on the surface of the nonwoven material is 0.2 mm, and the distance T between two adjacent grooves is 0.5 mm.

[0130] No plasticizer is applied in the production of the nonwoven material.

[0131] A filter rod forming machine group KDF2 / AF1 is used to process the nonwoven material to obtain a filter rod for cigarettes. The circumference of the filter rod is 16.70 mm, the length is 120 mm, the pressure drop is 6.92 kPa, and the weight is 0.40-0.42 g / rod.

[0132] The surface of the nonwoven material is rolled to form a groove texture, and the filter rod processed by using the composite nonwoven material has through holes for smoke diffusion and circulation. Compared with the example embodiment described above, the filling rate of the filter rod in this embodiment is increased by 5%-10%, and the pressure drop of the filter rod is reduced by 30%.

[0133] Embodiment 2

[0134] The nonwoven material used for processing the filter rod is composed of acetate fibers and polylactic acid fibers, wherein the single-fiber linear density of the acetate fibers is 1.3 denier, and the mass ratio of the acetate fibers is 80%; the single-fiber linear density of the polylactic acid fibers is 1.56 denier, and the mass ratio of the polylactic acid fibers is 20%. In this embodiment, the nonwoven material is processed by using the straight-laid method. The nonwoven material has a longitudinal strength close to a transverse strength, a longitudinal-transverse strength sum of 60-80 N / 5 cm, a crimp number of 10-30 per 25 mm, a thickness of the straight-laid web of 0.35 mm, a grammage of 45±5 g / m 2The nonwoven material has a cross-cut width of 67 mm. The amplitude L of the grooves formed on the surface of the nonwoven material is 0.4 mm, and the distance T between two adjacent grooves is 0.9 mm.

[0135] No plasticizer is added during the production of the composite nonwoven material.

[0136] A filter rod for cigarettes is produced using the nonwoven material as raw material by means of a KDF2 / AF1 filter rod forming machine. The circumference of the filter rod is 16.70 mm, the length is 120 mm, the pressure drop is 6.92 kPa, and the weight is 0.40-0.42 g / rod.

[0137] The surface of the nonwoven material is roll-pressed to form groove texture. The filter rod produced using the nonwoven material has through-flow holes in front and back. Compared with the exemplary embodiments described above, the filter rod in this embodiment has an increased filling rate of 5%-10% and a decreased pressure drop of 30%.

[0138] Example 3

[0139] The nonwoven material used for producing the filter rod has a cellulose acetate monofilament linear density of 1.5 denier, and the mass ratio of cellulose acetate is 100%. The nonwoven material is produced by cross-laying. The longitudinal and transverse strengths of the nonwoven material are close to each other, the longitudinal and transverse strength sum is 64-80 N / 5 cm, the number of crimps is 13-26 per 25 mm, the cross-laying thickness is 0.37 mm, and the grammage is 45±5 g / m 2 The nonwoven material has a cross-cut width of 67 mm. The amplitude L of the grooves formed on the surface of the nonwoven material is 0.3 mm, and the distance T between two adjacent grooves is 0.8 mm.

[0140] No plasticizer is added during the production of the nonwoven material.

[0141] A filter rod for cigarettes is produced using the nonwoven material as raw material by means of a KDF2 / AF1 filter rod forming machine. The circumference of the filter rod is 16.70 mm, the length is 120 mm, the pressure drop is 5.75 kPa, and the weight is 0.43-0.46 g / rod.

[0142] The surface of the nonwoven material is roll-pressed to form groove texture. The filter rod produced using the nonwoven material has through-flow holes in front and back. Compared with the exemplary embodiments described above, the filter rod in this embodiment has an increased filling rate of 5%-10% and a decreased pressure drop of 30%.

[0143] Example 4

[0144] The nonwoven material for processing filter rod is composed of acetate fiber and polylactic acid fiber, wherein the linear density of acetate fiber monofilament is 1.3 denier, the mass ratio is 80%, the linear density of polylactic acid fiber monofilament is 1.56 denier, and the mass ratio is 20%. The composite nonwoven material is processed into shape by cross-laying method, the longitudinal and transverse strength of the nonwoven material is close, the longitudinal and transverse strength sum is 64-80 N / 5 cm, the number of crimps is 13-26 per 25 mm, the thickness of cross-laying is 0.37 mm, the grammage is 45±5 g / m 2 , and the slitting width is 67 mm. The amplitude L of the groove formed on the surface of the nonwoven material is 0.4 mm, and the distance T between two adjacent grooves is 0.8 mm.

[0145] No plasticizer is applied in the production process of the nonwoven material.

[0146] The nonwoven material is processed into filter rod for cigarettes by using KDF2 / AF1 filter rod forming machine group, the circumference of the filter rod is 16.70 mm, the length is 120 mm, the pressure drop is 5.75 kPa, and the weight is 0.43-0.46 g / rod.

[0147] The filter rod made of the nonwoven material has a plurality of through airflow channels, compared with the exemplary embodiment described above, the filling rate of the filter rod in this embodiment is increased by 13%-21%, and at the same time, the pressure drop of the filter rod is reduced by 42%.

[0148] Example 5

[0149] The fabric material is used to process filter rod, the fabric material is composed of acetate fiber and cotton fiber, wherein the linear density of acetate fiber monofilament is 1.3 denier, the mass ratio is 60%, and the mass ratio of cotton fiber is 40%. The yarn of the fabric material is 60 s / 1, and is processed by twill weaving. The longitudinal and transverse strength of the fabric material is close, the grammage is 130 g / m 2 , the number of crimps is 13-26 per 25 mm, the thickness is 0.37 mm, and the slitting width is 67 mm. The amplitude L of the groove is 0.3 mm, and the distance T between two adjacent grooves is 0.6 mm.

[0150] The fabric material is processed into filter rod for cigarettes by using KDF2 / AF1 filter rod forming machine group, the circumference of the filter rod is 16.70 mm, the length is 120 mm, the pressure drop is 6.12 kPa, and the weight is 0.40-0.43 g / rod.

[0151] The filter rod made of the fabric material has a plurality of through airflow channels, compared with the exemplary embodiment described above, the filling rate of the filter rod in this embodiment is increased by 5%-10%, and at the same time, the pressure drop of the filter rod is reduced by 38%.

[0152] Example 6

[0153] The linear density of the acetate fiber filaments used in the nonwoven material for processing filter rods is 1.3 denier, with a mass ratio of 100% acetate fiber. The nonwoven material is processed using cross-laying, with a longitudinal and transverse strength sum of 52 N / 5 cm, a curl number of 18-20 per 25 mm, a thickness of 0.27 mm, and a grammage of 38 g / m 2 , with a slitting width of 67 mm.

[0154] The amplitude L of the grooves formed on the surface of the nonwoven material is 0.4 mm, and the spacing T between two adjacent grooves is 1.0 mm.

[0155] No plasticizer is applied during the production of the nonwoven material.

[0156] A filter rod for cigarettes is processed using a KDF2 / AF1 filter rod forming machine set and using the nonwoven material as the raw material, with a circumference of 16.70 mm, a length of 120 mm, a pressure drop of 6.92 kPa, and a weight of 0.46-0.49 g per rod.

[0157] The surface of the nonwoven material is roll-pressed to form groove textures, and the filter rod processed using the nonwoven material has through air flow channels. Compared with the exemplary embodiments described above, the filter rod in this embodiment has an increased filling rate of 21-26%, and a reduced pressure drop of 30%.

[0158] The products of the present application are detected using known technologies and equipment. In the above Examples 1-6, a QTM filter rod comprehensive test bench is used for detection, which includes test units for weight (QTM8), circumference (QTM3), draw resistance (QTM5 / QTM6), and hardness (QTM7).

[0159] Draw resistance is defined as the pressure difference generated when a stable air flow (usually 17.5 ml / s) passes through the filter rod, with the unit being pascal (Pa).

[0160] Hardness is defined as the ability of the filter rod to resist external pressure, reflecting its elasticity and firmness, with the unit being percentage ratio.

[0161] Filter rod circumference is defined as the length of the cross-sectional perimeter of the filter rod, with the unit being millimeter (mm).

[0162] Performance standards: the standard for draw resistance is GB / T 22838.5-2024, the standard for circumference is GB / T 22838.3-2009 (currently being revised), and the standard for hardness is GB / T 22838.6-2024. For the sake of brevity, the detailed contents of the detection are not described again.

[0163] The above description and the accompanying examples are intended to be illustrative of the application and are not intended to limit the scope of the application. Those skilled in the art will readily recognize variations and modifications of the embodiments discussed herein which fall within the scope of the application. Accordingly, the application is limited only by the appended claims.

Claims

1. A smoking article filter rod characterised in that: The non-woven material or fabric material is made of a plurality of front and rear through holes; the non-woven material or fabric material contains at least part of acetate fibers, and the surface of the non-woven material or fabric material is provided with groove texture formed by a plurality of grooves, and the mass ratio of the acetate fibers is 1-100%.

2. A smoking article filter rod according to claim 1 characterised in that: The non-woven material or fabric material also contains hot melt fibers or cotton fibers, and the mass ratio of the hot melt fibers or cotton fibers is 0-99%; preferably, the mass ratio of the acetate fibers is 60-100%, and the mass ratio of the hot melt fibers or cotton fibers is 0-40%; optionally, the hot melt fibers include polylactic acid fibers.

3. A smoking article filter rod according to claim 1 characterised in that: The single filament linear density of the acetate fibers is 1.0-12.0 denier, preferably 1.0-6.0 denier, and more preferably 1.0-3.5 denier.

4. A smoking article filter rod according to claim 1 characterised in that: The nonwoven material has a grammage of 30 to 150 g / m 2 , preferably 35 to 80 g / m 2 , more preferably 40 to 50 g / m 2 .

5. A smoking article filter rod according to claim 1 characterised in that: The thickness of the non-woven material is 0.2-0.80 mm, preferably 0.31-0.40 mm.

6. A smoking article filter rod according to claim 5, characterised in that: The longitudinal and transverse strength of the non-woven material is 60-80 N / 5 cm.

7. A smoking article filter rod according to claim 3 characterised in that: The single filament crimp number of the acetate fibers is 13-26 / 25 mm, preferably 16-22 / 25 mm.

8. A smoking article filter rod according to claim 1 characterised in that: The groove is one of a straight groove extending along a straight line, a curved groove extending along an S-shaped curve, and a broken line groove extending along a broken line.

9. A smoking article filter rod according to claim 8 characterised in that: A plurality of parallel partition grooves are arranged in the groove, and the partition grooves on adjacent two grooves are staggered.

10. A smoking article filter rod according to claim 8, characterised in that: The surface of the non-woven material is also provided with a plurality of diagonal grooves at an angle to the straight grooves.

11. A smoking article filter rod according to claim 8, characterised in that: The cross section of the non-woven material or fabric material with a plurality of grooves on the surface is wave-shaped, the amplitude L of the groove is 0.2-0.4 mm, and the spacing T of two adjacent grooves is 0.5-1.0 mm.

12. A smoking article filter rod according to claim 1 characterised in that: It is made of the non-woven material or fabric material by one or more of folding, winding, and gathering.

13. A smoking article filter rod according to claim 1 characterised in that: The non-woven material or fabric material is an acetate fiber non-woven fabric with a skeleton structure composed of acetate fibers with two or more single filament linear densities; Optionally, the acetate fiber non-woven fabric is made of 100% acetate fibers by mass percentage; Optionally, the filter rod has pores distributed in the non-woven material or fabric material, and the porosity is 20%-96%, preferably 50%-96%, and more preferably 90%-96%; Optionally, the filter rod is cylindrical, and the circumference is 14-28 mm and the diameter is 4.5-9 mm; Optionally, the acetate fiber non-woven fabric is a three-dimensional arranged web structure with area density and thickness, which contains a plurality of layers of thin fiber webs stacked together, each layer of thin fiber web is formed by carding fibers into single fiber state, and the surface contains fluff; Optionally, the weight of the acetate fiber nonwoven fabric is 25-40 g / m 2 , preferably 30-40 g / m 2 . Optionally, the thickness of the acetate fiber non-woven fabric is 0.05-0.80 mm, preferably 0.2-0.60 mm; Optionally, the relatively thick acetate fibers provide support as a skeleton, and the relatively thin fibers have a large specific surface area to play an adsorption role. Optionally, the relatively thin acetate fibers are 0.8-1.6 denier, and the mass percentage is 60%-80%; the relatively thick acetate fibers are 2.0-8.0 denier, preferably 2.0-3.5 denier, and the mass percentage is 20%-40%; Optionally, the length of the acetate fibers is 15-80 mm, preferably 30-60 mm; Optionally, the number of crimps of the acetate fibers is 8-30 per 25 mm, preferably 8-20 per 25 mm, and more preferably 8-15 per 25 mm; Optionally, the preparation method of the acetate fiber nonwoven fabric comprises the steps of combing, laying, and fixing the acetate fibers to produce the acetate fiber nonwoven fabric; Optionally, the preparation method of the acetate fiber nonwoven fabric is that the mixing of acetate fibers with different filament linear densities is performed in the spinning stage; Optionally, the laying method of the acetate fiber nonwoven fabric is straight laying and / or cross laying; Optionally, the fixing method of the acetate fiber nonwoven fabric comprises one or a combination of two or more of water jet, hot rolling, chemical bonding, and seaming; Optionally, the preparation method of the acetate fiber nonwoven fabric is that the mixing of acetate fibers with different filament linear densities is performed in the spinning stage, and the acetate fibers with different filament linear densities are uniformly mixed; Optionally, the wrapping material is a sheet material, including but not limited to cellulose paper, cellulose acetate film, and PET film; optionally, the thickness of the sheet material is not greater than 4 mm, preferably not greater than 2 mm, and preferably the thickness is 0.02-0.5 mm; Optionally, the filter rod is formed into a porous structure by at least one of folding, winding, and gathering, and the wrapping material wraps the porous structure in the radial direction.

14. A smoking article filter rod according to claim 1 characterised in that: The nonwoven material or fabric material comprises high-density regions and low-density regions; Optionally, the nonwoven material or fabric material is mixed from single fibers or multi-component fibers; the fibers are high-molecular fibers, including but not limited to any one or a combination of cellulose, regenerated cellulose, cellulose derivatives, starch-based thermoplastic resins, cellulose acetate, polylactic acid, chitosan and its derivatives, polyhydroxybutyrate, poly-ε-caprolactone, polyglycolic acid, polyhydroxyalkanoate, polypropylene, polyethylene, polyvinyl alcohol, polyester, polyamide, polyurethane, and polyacrylonitrile; Optionally, the nonwoven material or fabric material is a composite acetate fiber nonwoven fabric made of acetate fibers and other fibers; Optionally, the mass percentage of the acetate fibers in the nonwoven material or fabric material is 0%-100%; Optionally, when the mass percentage of the acetate fibers in the nonwoven material or fabric material is 0, the other fibers are 100% polylactic acid; Optionally, the nonwoven or woven material has a grammage of 30 to 80 g / m 2 , preferably 35 to 60 g / m 2 , more preferably 40 to 50 g / m 2 . Optionally, the longitudinal and transverse strength of the nonwoven material or fabric material is 20-80 N / 5 cm, preferably 30-60 N / 5 cm, and more preferably 35-50 N / 5 cm; Optionally, the nonwoven or fabric material has a density of 0.1-1.3 g / cm 3 0.05-0.5 mm, preferably 0.1-0.4 mm, more preferably 0.2-0.3 mm; Optionally, the high-density area plays a role of fixing the fiber web, stabilizing the structure, and enhancing the hardness; the density of the high-density area is ≤1.3 g / cm 3 The surface of the low-density area is smooth and has no fluff structure; the density of the low-density area is ≥0.1 g / cm 3 Optionally, the shape of the high-density area structure can be, but is not limited to, one or a combination of a circle, a rectangle, a square, a diamond, a rhombus, a wave, a diagonal line, and a broken line, and the area ratio is 5%-99% of the total area, preferably 5%-25%. Optionally, the low-density region is a continuous structure, and the high-density region is composed of several independent parts dispersed in the low-density region; or the high-density region is a continuous structure, and the low-density region is composed of several independent parts dispersed in the high-density region; Optionally, the acetate fiber used for preparing the non-woven material or fabric material has a linear density of 0.8-22.0 denier, preferably 1.0-6.0 denier, and more preferably 1.0-1.6 denier; Optionally, the acetate fiber used for preparing the non-woven material or fabric material has a crimp number of 8-30 per 25 mm, preferably 8-20 per 25 mm, and more preferably 8-15 per 25 mm; Optionally, the acetate fiber and other fibers used for preparing the non-woven material or fabric material have a length of 15 mm-80 mm; Optionally, the acetate fiber used for preparing the non-woven material or fabric material has a cross-section in the shape of a circle, X, or Y; Optionally, the method for preparing the non-woven material or fabric material used for the smoke filtering element comprises the following steps: preparing the composite acetate fiber non-woven fabric through hot-rolling treatment of a fiber web to obtain the non-woven material or fabric material; the fiber web comprises a fiber web formed by direct carding and a non-woven fabric formed after solidification of the fiber web, such as water jet; Optionally, the step of forming the fiber web by direct carding comprises the following steps: mixing and opening the fibers before carding, uniformly mixing other fibers with different physical properties with the acetate fibers in proportion, then carding the mixed fibers into a single fiber state, making the fibers into a thin fiber web state, and then stacking one layer of the thin fiber web to increase the area density and thickness through a web laying process; Optionally, the web laying process can be straight laying, cross laying, or a combination of straight laying and cross laying; Optionally, the step of hot-rolling treatment comprises the following step: hot-rolling and pressing the fiber web through two oppositely arranged rollers; Optionally, one of the rollers is a metal roller, and the other is a metal roller, a rubber roller, or a nylon roller; Optionally, when the metal roller has patterns, the part of the fiber web that contacts the raised pattern part of the metal roller is rolled into a high-density region, and the part of the fiber web that contacts the remaining part of the metal roller is rolled into a low-density region; when the metal roller has no patterns, the single density area accounts for 100% of the total area after the hot-rolling treatment; Optionally, the surface temperature of the roller is 110-230℃, the rolling pressure is 0.01-4.5 MPa, preferably 0.01-2.5 MPa, and more preferably 0.01-0.5 MPa, and the roller rotation speed is 10-45 m / min; Optionally, the step of hot-rolling treatment of the acetate fiber non-woven fabric can be performed in the filter rod forming process.

15. A smoking article filter rod according to claim 1 characterised in that: The shape of the filter rod for cigarettes comprises a cylindrical shape; preferably, the circumference of the filter rod for cigarettes is in the range of 15.8 mm to 31.4 mm, more preferably, the circumference is between 16.00 mm and 22.00 mm, and more preferably, the circumference is between 16.20 mm and 16.80 mm.

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