A method of manufacturing a hollow filter rod

Abstract

The application provides a preparation method of a hollow filter rod, and the preparation method comprises the following steps: after opening a cellulose diacetate fiber tows, the cellulose diacetate fiber tows are mixed with a plasticizer, and then pre-mixing, shaping and slitting are performed to obtain the hollow filter rod. The preparation method provided by the application improves the uniformity of the cellulose diacetate fiber tow filling, improves the bonding effect of the hollow filter rod, avoids the situation that the hollow filter rod is prone to delamination, deformation or even rupture during use, and meanwhile, the pattern reduction degree is high, and the appearance performance of the filter rod is improved.

Description

Technical Field

[0001] This invention belongs to the field of cigarette filter rod preparation technology, specifically relating to a method for preparing a hollow filter rod, and more particularly to a method for preparing a hollow filter rod with good bonding effect. Background Technology

[0002] With the continuous development of cigarette filter technology, hollow filter rods, with their novel appearance and easy smoking experience, are increasingly favored by consumers. Major cigarette companies have also successively launched branded hollow filter rod cigarettes. During the cigarette packing process, the hollow filter rod needs to be squeezed by a rubbing board and wrapped with tipping paper. During this process, the hollow filter rod is prone to delamination, deformation, and even breakage due to the compression, a problem that seriously affects cigarette production.

[0003] CN115153089A discloses a hollow filter tube, its preparation method, and its application. The hollow filter tube provided by this invention, by using a thermally conductive material with a specific ratio and composition to modify the tube body, enhances the heat exchange capacity of the hollow tube structure, improves the cooling capacity of the hollow filter tube, and prevents excessively high inhaled smoke temperatures from harming the smoker. The thermally conductive material also includes a binder, improving the adhesion between the thermally conductive material and the hollow filter tube body, and achieving a multi-layer coating effect, further enhancing the cooling capacity. Furthermore, the thermally conductive material contains flavoring substances, which can be activated during heat exchange, increasing the richness of the smoke's aroma components and providing consumers with a safer and more comfortable smoking experience.

[0004] CN111109651B discloses a method for preparing a biodegradable composite fiber adhesive-free hollow filter rod. The method includes the following steps: (1) filament selection: select a fully biodegradable composite fiber tobacco filament with a linear density of 8-15 ktex; (2) opening: open the filament on a commercially available improved hollow filter rod forming unit; (3) forming and cutting: the opened filament is sequentially introduced into the dry hot air section tobacco gun, the cooling section tobacco gun, and the forming and cutting to obtain a biodegradable fiber adhesive-free hollow filter rod. The filter rod is rolled into shape without adding any plasticizer or adhesive, which reduces the production cost and eliminates the harm to the human body from trace harmful substances in plasticizers or adhesives. It is safe and pollution-free.

[0005] CN111387546A discloses a Venturi-type hollow filter rod for heating cigarettes. The outer surface of the hollow filter rod body is a relatively smooth cylindrical structure, and the interior is provided with an axial hollow cavity. Along the axial direction of the hollow filter rod body, the structure of the hollow cavity exhibits a periodic and continuous change in cavity diameter, forming a series of coarse and fine cavities connected in series. When the smoke passes through the cavity, the change in cavity structure causes a change in the flow velocity of the smoke fluid, forcing the fluid state from laminar flow to turbulent flow, improving the heat conduction efficiency, and thus having a better heat transfer and cooling effect. At the same time, when the smoke aerosol passes through the Venturi-type hollow filter rod, due to the continuous alternating change in the diameter of the internal hollow cavity, the aerosol collides and condenses, releasing heat, further enhancing the cooling effect. When this filter rod is used to heat cigarettes, it can ensure the amount of smoke atomization while cooling, and also satisfy the smoker's experience.

[0006] However, none of the aforementioned patents address the problems that arise when hollow filter rods are compressed, nor do they provide corresponding solutions. Therefore, how to provide a method that can effectively solve the problems of delamination, deformation, and even breakage of hollow filter rods after compression, and ensure the smooth operation of cigarette production, has become an urgent issue to be addressed. Summary of the Invention

[0007] To address the shortcomings of existing technologies, the present invention aims to provide a method for preparing hollow filter rods, particularly a method for preparing hollow filter rods with good bonding effect. The preparation method provided by the present invention improves the uniformity of cellulose acetate bundle filling, enhances the bonding effect of the hollow filter rod, and avoids delamination, deformation, and even breakage that easily occur during use. Simultaneously, it achieves high pattern fidelity, improving the aesthetic appearance of the filter rod.

[0008] To achieve this objective, the present invention employs the following technical solution:

[0009] This invention provides a method for preparing hollow filter rods, the method comprising the following steps:

[0010] After the cellulose acetate bundles are opened, they are mixed with plasticizers, and then premixed, shaped, and slit to obtain the hollow filter rods.

[0011] The above method, by premixing the cellulose acetate bundles with plasticizer, can effectively improve the uniformity of the cellulose acetate bundle filling. Combined with plasticizer, it can improve the bonding effect of hollow filter rods, avoiding delamination, deformation or even cracking that are prone to occur during use. At the same time, the bottom pattern of the filter rod has high fidelity, which improves the aesthetic appearance of the filter rod.

[0012] Preferably, the plasticizer comprises any one or a combination of at least two of triacetin, polyethylene glycol, triethylene glycol diacetate, or triethyl citrate.

[0013] Preferably, the plasticizer comprises a combination of triacetin, polyethylene glycol, and triethylene glycol diacetate.

[0014] The aforementioned specific plasticizer combination can effectively improve the bonding effect of hollow filter rods, avoiding delamination, deformation, or even cracking that can easily occur during the use of hollow filter rods.

[0015] Preferably, the mass ratio of triacetin, polyethylene glycol, and triethylene glycol diacetate is (4-8):(1-3):(1-3), wherein the amount of triacetin can be 4, 5, 6, 7, or 8, the amount of polyethylene glycol can be 1, 1.5, 2, 2.5, or 3, and the amount of triethylene glycol diacetate can be 1, 1.5, 2, 2.5, or 3, but is not limited to the values ​​listed above. Other unlisted values ​​within the above range are also applicable.

[0016] Preferably, the mass of the plasticizer is 10-30% of the mass of the cellulose diacetate tow, such as 10%, 15%, 20%, 25% or 30%, but not limited to the values ​​listed above. Other unlisted values ​​within the above range are also applicable.

[0017] Preferably, the plasticizer is kept warm before use, and the warming temperature is 30-60℃, such as 30℃, 35℃, 40℃, 45℃, 50℃, 55℃ or 60℃, but not limited to the values ​​listed above. Other values ​​not listed in the above range are also applicable.

[0018] Preferably, the premixing is performed using a filament premixing device, which includes an upper bundling roller and a lower bundling roller.

[0019] Preferably, the opening angle of the upper gathering roller is 90°-150°, such as 90°, 100°, 110°, 120°, 130°, 140° or 150°, but is not limited to the values ​​listed above. Other unlisted values ​​within the above range are also applicable.

[0020] Preferably, the opening angle of the lower bundling roller is 30°-90°, such as 30°, 40°, 50°, 60°, 70°, 80° or 90°, but not limited to the values ​​listed above. Other unlisted values ​​within the above range are also applicable.

[0021] Preferably, the opening angle of the lower bundling roller is smaller than that of the upper bundling roller.

[0022] Preferably, the width of the upper gathering roller is 15-30cm, such as 15cm, 16cm, 17cm, 18cm, 19cm, 20cm, 21cm, 22cm, 23cm, 24cm, 25cm, 26cm, 27cm, 28cm, 29cm or 30cm, but is not limited to the values ​​listed above. Other unlisted values ​​within the above range are also applicable.

[0023] Preferably, the width of the lower gathering roller is 5-15cm, such as 5cm, 6cm, 7cm, 8cm, 9cm, 10cm, 11cm, 12cm, 13cm, 14cm or 15cm, but is not limited to the values ​​listed above. Other unlisted values ​​within the above range are also applicable.

[0024] Preferably, the width of the upper bundling roller is not less than the width of the lower bundling roller.

[0025] The aforementioned specific filament premixing device and its parameter settings can bundle filaments with large widths after opening, effectively improving the uniformity of filament filling and thus improving the bonding effect. In addition, the opening angle of the upper bundling roller is greater than that of the lower bundling roller. The opened filaments first pass through the upper bundling roller and then through the lower bundling roller into the filament catcher, which can realize the gradual gathering of filaments and prevent filaments with large opening widths from overflowing the bundling roller, thereby improving the bonding effect.

[0026] Preferably, the upper and lower bundle rollers are made of anti-adhesion materials (such as stainless steel or aluminum) and undergo anti-adhesion treatment (such as polishing or anti-adhesion coating). These processes can effectively prevent the filament bundles from sticking together.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] This invention provides a method for preparing hollow filter rods. By premixing cellulose acetate bundles with plasticizer, the uniformity of cellulose acetate bundle filling can be effectively improved. Combined with plasticizer, the bonding effect of hollow filter rods can be improved, avoiding delamination, deformation or even cracking that easily occurs during use. At the same time, the bottom pattern of the filter rod has high fidelity, improving the aesthetic appearance of the filter rod. Attached Figure Description

[0029] Figure 1 These are schematic diagrams of the production apparatus in Examples 1-3;

[0030] Figure 2 This is a schematic diagram of the tow premixing device in Examples 1-3;

[0031] Among them, 1-first air opening device, 2-second air opening device, 3-stabilizing roller, 4-first opening roller, 5-second opening roller, 6-third air opening device, 7-plasticizer spraying device, 8-output roller, 9-filament premixing device, 10-filament catcher, 11-heating module, 12-cooling module, 13-forming smoke gun, 14-slitting device, 91-upper bundling roller, 92-first synchronous belt pulley, 93-synchronous belt, 94-lower bundling roller, 95-second synchronous belt pulley, 96-servo motor, 97-displacement platform;

[0032] Figure 3 These are scanning electron microscope images of the hollow filter rods prepared in Example 1;

[0033] Figure 4 This is a scanning electron microscope image of the hollow filter rod prepared in Comparative Example 1. Detailed Implementation

[0034] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0035] In the following examples, triethylene glycol diacetate and polyethylene glycol were purchased from Zhengzhou Xinqiao Tobacco Service Co., Ltd., and triacetin was purchased from Jiangsu Raymond New Materials Co., Ltd. The purity of triacetin and triethylene glycol diacetate was ≥99%, and the molecular weight of polyethylene glycol was 200-800.

[0036] Example 1

[0037] This embodiment provides a method for preparing hollow filter rods, using methods such as... Figure 1 The production apparatus shown is used for preparation, 1 is the first air opening device, 2 is the second air opening device, 3 is the stabilizing roller, 4 is the first opening roller, 5 is the second opening roller, 6 is the third air opening device, 7 is the plasticizer spraying device, 8 is the output roller, 9 is the filament premixing device, 10 is the filament catcher, 11 is the heating module, 12 is the cooling module, 13 is the forming smoke gun, and 14 is the slitting device.

[0038] After the cellulose acetate tow is opened by the three-stage air opening devices 1, 2, and 6 and the opening rollers 4 and 5, the plasticizer is sprayed onto the opened cellulose acetate tow by the plasticizer spraying device 7. The output roller 8 feeds the tow into the tow premixing device 9 for mixing, and the fiber catcher 10 feeds the tow into the heating module 11 for shaping. The tow is then formed into a corresponding hollow pattern by a mandrel of a specific shape placed in the heating module 11. After being cured into a filter bar by the cooling module 12, it is fed into the slitting device 14 by the forming smoke gun 13 to be slit into hollow filter rods. The hollow filter rod end face pattern is inspected by the hollow filter rod end face visual inspection device, and hollow filter rods with poor end face pattern reproduction are rejected.

[0039] The plasticizer consists of triacetyl ester, polyethylene glycol, and triethylene glycol diacetate (mass ratio 7:2:2), with an application rate of 25%. Before use, each plasticizer component is stirred and mixed under heating at 40°C and stored in the large plasticizer tank of the molding equipment. The large plasticizer tank contains a stirring paddle and a heating device to ensure the uniformity of the mixture. A suction pump is used to draw the mixture into a small plasticizer tank, and a vacuum pump is used for degassing to prevent air bubbles from affecting the uniformity of plasticizer spraying. The mixture is then evenly sprayed onto the opened diacetyl cellulose tows through heated nozzles using the suction pump. Both the large and small plasticizer tanks, nozzles, and pipelines require insulation (60°C).

[0040] The structure of the tow premixing device is as follows Figure 2 As shown, it consists of an upper bundling roller 91, a lower bundling roller 94, a first synchronous pulley 92, a second synchronous pulley 95, a synchronous belt 93, a servo motor 96, and a displacement platform 97. The upper bundling roller has an opening angle α of 120° and a width of 20cm, while the lower bundling roller has an opening angle β of 60° and a width of 10cm. Both the upper and lower bundling rollers are made of stainless steel, with polished surfaces and a polytetrafluoroethylene coating to prevent the filaments from sticking together. The upper and lower bundling rollers are driven by synchronous pulleys 92 and 95, which are in turn driven by the servo motor 96. The electrical signal of the servo motor 96 is read from the main motor signal by an encoder to control the motor speed and ensure that the linear speed of the bundling roller is consistent with that of the main motor.

[0041] The fiber bonding in the hollow filter rod was observed using a scanning electron microscope. Figure 3 This indicates that effective bonding exists within it.

[0042] Example 2

[0043] This embodiment provides a method for preparing hollow filter rods, using methods such as... Figure 1 The production apparatus shown is used for preparation, 1 is the first air opening device, 2 is the second air opening device, 3 is the stabilizing roller, 4 is the first opening roller, 5 is the second opening roller, 6 is the third air opening device, 7 is the plasticizer spraying device, 8 is the output roller, 9 is the filament premixing device, 10 is the filament catcher, 11 is the heating module, 12 is the cooling module, 13 is the forming smoke gun, and 14 is the slitting device.

[0044] After the cellulose acetate tow is opened by the three-stage air opening devices 1, 2, and 6 and the opening rollers 4 and 5, the plasticizer is sprayed onto the opened cellulose acetate tow by the plasticizer spraying device 7. The output roller 8 feeds the tow into the tow premixing device 9 for mixing, and the fiber catcher 10 feeds the tow into the heating module 11 for shaping. The tow is then formed into a corresponding hollow pattern by a mandrel of a specific shape placed in the heating module 11. After being cured into a filter bar by the cooling module 12, it is fed into the slitting device 14 by the forming smoke gun 13 to be slit into hollow filter rods. The hollow filter rod end face pattern is inspected by the hollow filter rod end face visual inspection device, and hollow filter rods with poor end face pattern reproduction are rejected.

[0045] The plasticizer consists of triacetyl ester, polyethylene glycol, and triethylene glycol diacetate (mass ratio 8:1:1), with an application rate of 10%. Before use, each plasticizer component is stirred and mixed under heating at 30°C and stored in the large plasticizer tank of the molding equipment. The large plasticizer tank contains a stirring paddle and a heating device to ensure the uniformity of the mixture. A suction pump is used to draw the mixture into a small plasticizer tank, and a vacuum pump is used for degassing to prevent air bubbles from affecting the uniformity of plasticizer spraying. The mixture is then evenly sprayed onto the opened diacetyl cellulose tows through heated nozzles using the suction pump. Both the large and small plasticizer tanks, nozzles, and pipelines require insulation (40°C).

[0046] The structure of the tow premixing device is as follows Figure 2 As shown, it consists of an upper clustering roller 91, a lower clustering roller 94, a first synchronous pulley 92, a second synchronous pulley 95, a synchronous belt 93, a servo motor 96, and a displacement platform 97. The upper clustering roller has an opening angle α of 90° and a width of 15cm, while the lower clustering roller has an opening angle β of 30° and a width of 15cm. Both the upper and lower clustering rollers are made of aluminum, with polished surfaces and a polytetrafluoroethylene coating to prevent the filaments from sticking together. The upper and lower clustering rollers are driven by synchronous pulleys 92 and 95, which are in turn driven by the servo motor 96. The servo motor 96's electrical signal is read from the main motor signal by an encoder to control the motor speed, ensuring that the linear speed of the clustering roller is consistent with the linear speed of the main motor.

[0047] Example 3

[0048] This embodiment provides a method for preparing hollow filter rods, using methods such as... Figure 1 The production apparatus shown is used for preparation, 1 is the first air opening device, 2 is the second air opening device, 3 is the stabilizing roller, 4 is the first opening roller, 5 is the second opening roller, 6 is the third air opening device, 7 is the plasticizer spraying device, 8 is the output roller, 9 is the filament premixing device, 10 is the filament catcher, 11 is the heating module, 12 is the cooling module, 13 is the forming smoke gun, and 14 is the slitting device.

[0049] After the cellulose acetate tow is opened by the three-stage air opening devices 1, 2, and 6 and the opening rollers 4 and 5, the plasticizer is sprayed onto the opened cellulose acetate tow by the plasticizer spraying device 7. The output roller 8 feeds the tow into the tow premixing device 9 for mixing, and the fiber catcher 10 feeds the tow into the heating module 11 for shaping. The tow is then formed into a corresponding hollow pattern by a mandrel of a specific shape placed in the heating module 11. After being cured into a filter bar by the cooling module 12, it is fed into the slitting device 14 by the forming smoke gun 13 to be slit into hollow filter rods. The hollow filter rod end face pattern is inspected by the hollow filter rod end face visual inspection device, and hollow filter rods with poor end face pattern reproduction are rejected.

[0050] The plasticizer consists of triacetyl ester, polyethylene glycol, and triethylene glycol diacetate (mass ratio 4:3:3), with an application rate of 30%. Before use, each plasticizer component is stirred and mixed under heating at 60°C and stored in the large plasticizer tank of the molding equipment. The large plasticizer tank contains a stirring paddle and a heating device to ensure the uniformity of the mixture. A suction pump is used to draw the mixture into a small plasticizer tank, and a vacuum pump is used for degassing to prevent air bubbles from affecting the uniformity of plasticizer spraying. The mixture is then evenly sprayed onto the opened diacetyl cellulose tows through heated nozzles using the suction pump. Both the large and small plasticizer tanks, nozzles, and pipelines require insulation (70°C).

[0051] The structure of the tow premixing device is as follows Figure 2 As shown, it consists of an upper clustering roller 91, a lower clustering roller 94, a first synchronous pulley 92, a second synchronous pulley 95, a synchronous belt 93, a servo motor 96, and a displacement platform 97. The upper clustering roller has an opening angle α of 150° and a width of 30cm, while the lower clustering roller has an opening angle β of 90° and a width of 15cm. Both the upper and lower clustering rollers are made of aluminum, with polished surfaces and a polytetrafluoroethylene coating to prevent the filaments from sticking together. The upper and lower clustering rollers are driven by synchronous pulleys 92 and 95, which are in turn driven by the servo motor 96. The servo motor 96's electrical signal is read from the main motor signal by an encoder to control the motor speed, ensuring that the linear speed of the clustering roller is consistent with the linear speed of the main motor.

[0052] Example 4

[0053] This embodiment provides a method for preparing hollow filter rods. Except that the plasticizer does not contain triacetin and the reduced portion is allocated proportionally to polyethylene glycol and triethylene glycol diacetate, the rest is the same as in Example 1.

[0054] Example 5

[0055] This embodiment provides a method for preparing hollow filter rods. Except that the plasticizer does not contain polyethylene glycol and the portion is reduced and allocated proportionally to triacetin and triethylene glycol diacetate, the rest is the same as in Example 1.

[0056] Example 6

[0057] This embodiment provides a method for preparing hollow filter rods. Except that the plasticizer does not contain triethylene glycol diacetate and the reduced portion is allocated proportionally to polyethylene glycol and triacetyl ester, the rest is the same as in Example 1.

[0058] Example 7

[0059] This embodiment provides a method for preparing a hollow filter rod. Except that the opening angle α of the upper bundle roller is 80° and the opening angle β of the lower bundle roller is 20°, the rest is the same as in Embodiment 1.

[0060] Example 8

[0061] This embodiment provides a method for preparing a hollow filter rod. Except that the opening angle α of the upper bundle roller is 160° and the opening angle β of the lower bundle roller is 100°, the rest is the same as in Embodiment 1.

[0062] Example 9

[0063] This embodiment provides a method for preparing a hollow filter rod. Except that the opening angle α of the upper bundle roller is 80° and the opening angle β of the lower bundle roller is 90°, the rest is the same as in Embodiment 1.

[0064] Example 10

[0065] This embodiment provides a method for preparing hollow filter rods. Except that the width of the upper gathering roller is 10cm and the width of the lower gathering roller is 20cm, the rest is the same as in Embodiment 1.

[0066] Comparative Example 1

[0067] This comparative example provides a method for preparing hollow filter rods. Except that there is no fiber premixing device in the production device, that is, the output roller 8 does not send the fiber to the fiber premixing device, but directly sends the fiber to the heating module 11 for shaping (without premixing) by the fiber catcher 10. The rest is the same as in Example 1.

[0068] The fiber bonding in the hollow filter rod was observed using a scanning electron microscope. Figure 4 As can be seen, there is no obvious adhesion.

[0069] Effect test:

[0070] Hollow filter rods were prepared using the methods provided in Examples 1-10 and Comparative Example 1. A hardness test was performed on the middle section of each filter rod according to the relevant requirements of GB / T22838.6-2009. Twenty rods were used in each group, and the coefficient of variation of hardness was calculated based on the test data. The uniformity of the cellulose acetate bundle filling was determined based on the test results, as follows:

[0071] Example 1 1.96 Example 2 1.98 Example 3 1.97 Example 4 2.16 Example 5 2.10 Example 6 2.15 Example 7 2.0 Example 8 1.99 Example 9 2.10 Example 10 2.15 Comparative Example 1 2.2

[0072] The data above shows that the method provided by the present invention can effectively improve the uniformity of cellulose acetate bundle filling in hollow filter rods, making the hardness of each position of the hollow filter rod more consistent. Comparative Examples 1 and 4-10 show that the present invention can further improve the uniformity of cellulose acetate bundle filling by using a specific plasticizer and controlling the premixing parameters. Comparative Examples 1 and Comparative Example 1 show that the present invention can effectively improve the uniformity of cellulose acetate bundle filling by using a premixing method.

[0073] Next, the pattern on the bottom of the filter rod was compared with the design pattern to determine their similarity. The hollow filter rod was inserted into a comparison module with the design pattern affixed to its end face, and the similarity between the hollow filter rod pattern and the design pattern was compared. The similarity was graded into three levels: "very similar," "somewhat similar," and "somewhat dissimilar." Nine evaluators were selected to grade 11 examples, and the highest number of votes was used as the grade result. The results are as follows:

[0074] Example 1 Very similar Example 2 Very similar Example 3 Very similar Example 4 Similar Example 5 Similar Example 6 Similar Example 7 Very similar Example 8 Very similar Example 9 Similar Example 10 Similar Comparative Example 1 Less similar

[0075] The data above shows that the method provided by the present invention can effectively improve the pattern reproduction. Comparative Examples 1 and 4-10 show that the present invention, by using a specific plasticizer and controlling the premixing parameters, can further improve the bonding effect of the hollow filter rod, thereby improving the pattern reproduction and making the end face shape of the hollow filter rod more consistent with the design pattern. Comparative Examples 1 and Comparative Example 1 show that the present invention, by using a premixing method, can effectively improve the bonding effect and improve the pattern reproduction.

[0076] Hollow filter rods were then prepared using the methods provided in Examples 1-10 and Comparative Example 1 for cigarette production (one million cigarettes). Samples exhibiting filter rod delamination, deformation, or breakage were considered defective. The defect rate was calculated, and the results are as follows:

[0077] Defect rate (ppm) 13 15 16 46 55 53 Group Example 7 Example 8 Example 9 Example 10 Comparative Example 1 Defect rate (ppm) 19 18 46 48 168

[0078] The data above shows that the method provided by the present invention can effectively improve the bonding effect of hollow filter rods and reduce delamination, deformation, or even breakage of hollow filter rods during use. Comparative Examples 1 and 4-10 show that the present invention, by using a specific plasticizer and controlling the premixing parameters, can further improve the bonding effect of hollow filter rods, thereby improving their performance. Comparative Examples 1 and Comparative Example 1 show that the present invention, by using a premixing method, can effectively improve the bonding effect and effectively avoid delamination, deformation, or even breakage of hollow filter rods during use.

[0079] The applicant declares that the present invention illustrates the preparation method of the hollow filter rod through the above embodiments, but the present invention is not limited to the above embodiments, that is, it does not mean that the present invention must rely on the above embodiments to be implemented. Those skilled in the art should understand that any improvements to the present invention, equivalent substitutions of the raw materials of the product of the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

[0080] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.

[0081] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not describe the various possible combinations separately.

Claims

1. A method for preparing a hollow filter rod, characterized in that, The preparation method includes the following steps: After the cellulose acetate bundles are opened, they are mixed with plasticizer, and then premixed, shaped and cut to obtain the hollow filter rod. The premixing is performed using a filament premixing device, which includes an upper bundling roller and a lower bundling roller; the opening angle of the lower bundling roller is smaller than that of the upper bundling roller; and the width of the upper bundling roller is not less than the width of the lower bundling roller.

2. The method for preparing the hollow filter rod according to claim 1, characterized in that, The plasticizer includes any one or a combination of at least two of the following: triacetin, polyethylene glycol, triethylene glycol diacetate, or triethyl citrate.

3. The method for preparing the hollow filter rod according to claim 2, characterized in that, The plasticizer comprises a combination of triacetin, polyethylene glycol, and triethylene glycol diacetate.

4. The method for preparing the hollow filter rod according to claim 3, characterized in that, The mass ratio of triacetin, polyethylene glycol and triethylene glycol diacetate is (4-8):(1-3):(1-3).

5. The method for preparing a hollow filter rod according to claim 1, characterized in that, The mass of the plasticizer is 10-30% of the mass of the cellulose diacetate tow.

6. The method for preparing a hollow filter rod according to claim 1, characterized in that, The plasticizer is kept at a temperature of 30-60°C before use.

7. The method for preparing a hollow filter rod according to claim 1, characterized in that, The opening angle of the upper gathering roller is 90°-150°.

8. The method for preparing a hollow filter rod according to claim 1, characterized in that, The opening angle of the lower bundling roller is 30°-90°.

9. The method for preparing a hollow filter rod according to claim 1, characterized in that, The width of the upper gathering roller is 15-30 cm.

10. The method for preparing a hollow filter rod according to claim 1, characterized in that, The width of the lower gathering roller is 5-15 cm.

11. The method for preparing a hollow filter rod according to claim 1, characterized in that, The upper and lower bundling rollers are made of anti-sticking material and have undergone anti-sticking treatment.

Images