A cutting knife structure for cutting polylactic acid fiber filter rod

Abstract

The application provides a cutter structure for cutting polylactic acid fiber filter rods, and relates to the technical field of cigarette production. The cutter comprises a cutter shaft and a cutter, the cutter comprises a middle cutter and a side cutter, the middle cutter is circular, and the cutting edge of the side cutter is flush with the edge of the middle cutter; the hardness of the middle cutter is higher than that of the side cutter, so that the middle cutter is convenient for cutting the crystalline filaments in the polylactic acid fiber filter rod; and the side cutter is detachably arranged on the side of the middle cutter and is used for preventing triacetin from adhering to the side of the middle cutter. The application has the advantages that the cutter structure is simple in structure, the two cutters are arranged in cooperation, the hardness of the middle cutter is high to avoid the collision between the cutter and the random crystallization points in the polylactic acid fiber filaments, which can cause damage to the blade, the side cutter protects the middle cutter from being adhered by triacetin, the side cutter is detachably arranged and is convenient to replace, the whole structure has higher cutting efficiency for polylactic acid fiber filter rods, and the cutting stability is better.

Description

Technical Field

[0001] This invention relates to the field of cigarette manufacturing technology, and in particular, to a cutting structure for slitting polylactic acid fiber filter rods. Background Technology

[0002] Polylactic acid (PLA) is a polymer material produced by fermenting starch from renewable plant resources to obtain lactic acid, which is then chemically synthesized. It possesses excellent recyclability and biodegradability, exhibiting the following characteristics: 1. It uses renewable plant resources (corn, wheat, sugar beets, rice, potatoes, sweet potatoes, etc.) and organic waste (corn cobs or roots, stems, leaves, peels, etc. from other crops) as raw materials, eliminating dependence on wood and petroleum resources and meeting the requirements of sustainable development; 2. It is completely biodegradable, naturally decomposing into water and carbon dioxide in the natural environment over time, without causing environmental pollution. The generated carbon dioxide is reused through plant photosynthesis, forming a perpetual, closed carbon cycle system, making it a truly "green material"; 3. Compared with the three major synthetic fibers—polyester, nylon, and acrylic—the production of PLA fiber consumes less energy, making it a polymer material with relatively low resource and environmental impact; 4. It has good processing performance and can be produced as tow using general thermoplastic resin melt spinning methods.

[0003] Currently, polylactic acid (PLA) fibers have been developed for applications such as tobacco tow. However, there are significant differences in performance requirements between PLA fibers used in tobacco tow and those used in conventional clothing. For example, PLA fibers used in clothing must meet the requirements of fiber spinning, weaving, fabric printing and dyeing, washing, and ironing. They must have high crystallinity, orientation, and mechanical strength, be able to withstand temperatures of 80–100°C, be insoluble and non-swellable in detergent solutions and dry cleaning solvents, have a certain degree of hygroscopicity, and adsorb as little as possible from other gaseous substances in the surrounding environment. However, as tobacco tow, it needs to meet the following requirements: (1) The filter rods made from it are non-toxic, odorless, and safe; (2) The tow has good stability and can meet the requirements of filter rod forming equipment and processes; (3) It has suitable rigidity and curling performance, so that it has good elasticity and looseness. With a small amount of tow filling, after adding plasticizers or adhesives, the filter rod can meet certain requirements for hardness, suction resistance and appearance quality, and has a high yield; (4) It has sufficient heat resistance, so that the filter tip does not collapse or deform during cigarette smoking; (5) It has a high filtration efficiency for harmful components in the smoke; (6) It does not affect the sensory quality of cigarettes. Therefore, it is necessary to develop special spinning and post-processing technologies to meet the requirements for tobacco use.

[0004] For example, Chinese invention patent CN102763897A discloses a method for preparing polylactic acid fiber filter rods. The method includes the following steps: (1) opening: on a commercially available filter rod forming machine, polylactic acid fiber cigarette tow with a linear density of 3.5~5.0Ktex is opened; (2) applying adhesive: a biodegradable adhesive is sprayed onto the opened polylactic acid fiber cigarette tow; (3) forming and cutting; (4) drying the filter rod; (5) balancing: the dried filter rod is placed in a balancing chamber and balanced for more than 6 hours to obtain a polylactic acid fiber filter rod. The method for preparing polylactic acid fiber filter rods provided by the above invention can solve the problem of industrial production of polylactic acid fiber filter rods. It can be produced using existing commercially available filter rod forming machines. The cigarette smoke of the prepared filter rod is close to that of acetate fiber filter rods and can meet the requirements for cigarette use.

[0005] However, it should be noted that while polylactic acid (PLA) exhibits better temperature resistance when it has high crystallinity, it is also prone to forming knots. When the filaments are formed into filter rods, these knots are randomly distributed at different locations within the filament bundle. During the winding and slitting of the filter rods, the high-speed movement of the filter rods and the difference in force exerted on the cutter by the knots and filaments can easily cause notches or even breakage of the cutter blades, leading to frequent shutdowns of the winding machine, uneven cross-sections of the filter rods, filter rod deformation, and failure to meet roundness standards. Furthermore, compared to conventional cellulose acetate tow filter rods, PLA fiber filter rods contain triacetin, which may adhere to the outside of the cutter, further damaging it.

[0006] Clearly, the above preparation method does not take into account these problems that exist during the slitting process.

[0007] Therefore, in order to solve the above problems, it is necessary for us to design a reasonable and efficient cutting structure for cutting polylactic acid fiber filter rods. Summary of the Invention

[0008] The purpose of this invention is to provide a cutting structure for slitting polylactic acid fiber filter rods. The structure is simple to set up, with two cutting blades working together. The middle cutting blade has high hardness to avoid collision with random crystal points in the polylactic acid fiber bundles, which would cause blade damage. The side cutting blades protect the middle cutting blade from being stuck by triacetin. The side cutting blades are also detachable for easy replacement, making the entire structure more efficient and stable in slitting polylactic acid fiber filter rods.

[0009] To achieve the above objectives, the present invention employs the following technical solution: A cutting structure for slitting polylactic acid fiber filter rods includes a cutting shaft and a cutting blade disposed on the cutting shaft. The cutting blade includes a middle cutting blade and a side cutting blade. The middle cutting blade is circular, and the cutting edge of the side cutting blade is flush with the edge of the middle cutting blade. The hardness of the intermediate cutter is higher than that of the side cutter, making the intermediate cutter of the fiber bundle convenient for cutting the crystalline fiber bundles in the polylactic acid fiber filter rod. The side cutter is detachably disposed on the side of the middle cutter to prevent triacetin from adhering to the side of the middle cutter when cutting the polylactic acid fiber filter rod.

[0010] As a preferred embodiment of the present invention, the intermediate cutter is an alloy cutter, and the side cutter is a steel cutter.

[0011] As a preferred embodiment of the present invention, a grinding head is provided on the outer side of the side cutter, so that when the grinding head grinds the side cutter, the triacetin adhering to the side cutter is ground off.

[0012] As a preferred embodiment of the present invention, the side cutter includes a plurality of blade units, and each of the blade units extends from the cutter axis to the edge of the intermediate cutter.

[0013] As a preferred embodiment of the present invention, the cutting shaft is provided with a blade feeding device for connecting to one end of the blade unit near the cutting shaft. The blade feeding device includes a motor disposed outside the cutting shaft, a lead screw coaxially connected to the rotating shaft of the motor, and a blade clamp disposed on the lead screw for connecting to one end of the blade unit near the cutting shaft.

[0014] As a preferred embodiment of the present invention, the motor is a stepper motor.

[0015] As a preferred embodiment of the present invention, a limiting rod parallel to the lead screw is further provided between the motor and the blade clamp.

[0016] As a preferred embodiment of the present invention, the limiting rod and the lead screw are respectively located on both sides of the blade unit.

[0017] As a preferred embodiment of the present invention, there are two side cutters, and the two side cutters are closely attached to the two sides of the middle cutter.

[0018] As a preferred embodiment of the present invention, the end of the cutter shaft is provided with a drive motor for driving the cutter shaft to rotate.

[0019] The beneficial effects of the cutting structure for slitting polylactic acid fiber filter rods of the present invention are as follows: the design is simple, with two cutting blades working together. The middle cutting blade has high hardness to avoid collision with random crystallization points in the polylactic acid fiber bundle, which would cause blade damage. The side cutting blades protect the middle cutting blade from being stuck by triacetin, and the side cutting blades are detachable for easy replacement. This makes the entire structure more efficient at slitting polylactic acid fiber filter rods and has better cutting stability. Attached Figure Description

[0020] Figure 1 This is a three-dimensional structural schematic diagram of an embodiment of a cutting blade structure for slitting polylactic acid fiber filter rods according to the present invention; Figure 2 This is a side view schematic diagram of an embodiment of a cutting blade structure for slitting polylactic acid fiber filter rods according to the present invention; Figure 3 This is a side view of the side cutter structure in one embodiment of a cutter structure for slitting polylactic acid fiber filter rods according to the present invention; Figure 4 This is a schematic diagram of the knife feeding device in one embodiment of a cutting structure for slitting polylactic acid fiber filter rods according to the present invention; In the diagram: 1. Central cutter, 2. Side cutter, 20. Blade unit, 3. Cutter shaft, 4. Grinding head, 5. Cutter feed device, 51. Motor, 52. Lead screw, 53. Blade clamp, 54. Limiting rod, 00. Polylactic acid fiber bundle. Detailed Implementation

[0021] The following are specific embodiments of the present invention, which further describe the technical solution of the present invention, but the present invention is not limited to these embodiments.

[0022] Various exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It should be noted that, unless otherwise specifically stated, the relative arrangement and steps of the modules and steps set forth in these embodiments do not limit the scope of the invention.

[0023] At the same time, it should be understood that, for ease of description, the process shown in the attached diagram is not performed in isolation, but rather involves multiple steps that overlap.

[0024] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this invention is in use. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention. In addition, the terms "first," "second," etc., are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0025] The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the invention or its application or use.

[0026] Techniques, methods, and systems known to those skilled in the art may not be discussed in detail, but where appropriate, they should be considered part of this specification.

[0027] Example 1: As Figures 1 to 4 As shown, a cutting structure for slitting polylactic acid fiber filter rods includes a cutting shaft 3 and a cutting blade disposed on the cutting shaft 3. The cutting blade includes a middle cutting blade 1 and a side cutting blade 2. The middle cutting blade 1 is circular, and the cutting edge of the side cutting blade 2 is flush with the edge of the middle cutting blade 1. The hardness of the intermediate cutter 1 is higher than that of the side cutter 2, which makes the intermediate cutter 1 convenient for cutting the crystalline filaments in the polylactic acid fiber filter rod. The side cutter 2 is detachably disposed on the side of the intermediate cutter 1 to prevent triacetin from adhering to the side of the intermediate cutter 1 when cutting the polylactic acid fiber filter rod.

[0028] In this invention, two types of cutters are mounted on the same cutter shaft 3. When the cutter shaft 3 rotates, it simultaneously drives the two cutters to cut the polylactic acid fiber filter rod. The middle cutter 1 is circular and is the main body for cutting the polylactic acid fiber filter rod. Therefore, the outer edge of the middle cutter 1 cuts the polylactic acid fiber filter rod. In addition, the side cutter 2 is mounted on the outside of the middle cutter 1, so that the blade 2 of the side cutter 2 is flush with the edge of the middle cutter 1, and the polylactic acid fiber filter rod can be cut synchronously.

[0029] Here, the hardness of the intermediate cutter 1 is higher than that of the side cutter 2, which makes the intermediate cutter 1 convenient for cutting the crystalline filaments in the polylactic acid fiber filter rod. As the main body for cutting the polylactic acid fiber filter rod, the intermediate cutter 1 has high hardness and the blade is not easily damaged when it collides with the crystallization point.

[0030] In addition, the side cutter 2 is detachably disposed on the side of the middle cutter 1 to prevent triacetin from adhering to the side of the middle cutter 1 when cutting the polylactic acid fiber filter rod. The side cutter 2 blocks the outer side of the cutting part of the middle cutter 1, so that triacetin will only adhere to the side of the side cutter 2 away from the middle cutter 1, and will not adhere to the side of the middle cutter 1.

[0031] It should be noted that the blade 2 of the side cutter 2 is flush with the edge of the middle cutter 1. This is mainly to ensure that the side cutter 2 completely blocks the part of the middle cutter 1 that comes into contact with the polylactic acid fiber filter rod, so as to prevent triacetin from adhering to the side of the middle cutter 1.

[0032] The shape of the side cutter 2 can be varied. It can be circular or annular, only covering the outer part of the middle cutter 1. It can even be a series of long blades, with the outer ends of multiple long blades covering the outer part of the middle cutter 1.

[0033] In an embodiment of the present invention, the intermediate cutter 1 is an alloy cutter, and the side cutter 2 is a steel cutter.

[0034] Furthermore, there are two side cutters 2, and the two side cutters are closely attached to the two sides of the middle cutter 1. The alloy cutter is hard and not easily damaged, and the two steel cutters are closely attached to the outside of the alloy cutter, so that triacetin only sticks to the side of the steel cutter away from the alloy cutter.

[0035] Considering that the thickness of the steel blade (i.e., the blade unit 20) is much smaller than that of the alloy blade, even with two steel blades tightly attached to both sides of the alloy blade, the slitting effect of the combined cutter on the polylactic acid fiber filter rod is still not much different from that of the alloy blade alone. Moreover, since the blade of the steel blade is tightly attached to the alloy blade, the gap between the steel blade and the alloy blade has been proven to be extremely small. Due to the thickening effect of triacetin in the polylactic acid fiber filter rod, it will not affect the slitting effect of the polylactic acid fiber filter rod.

[0036] Furthermore, the side cutter 2 is detachable, allowing for periodic sharpening of the outer side of the steel blade, replacement when the steel blade is worn, or replacement of the steel blade when triacetin adhesion on the outer side is severe. This combined cutter structure of alloy blade and steel blade can easily cut highly crystalline polylactic acid fiber filter rods, making it less prone to damage, eliminating the need for frequent machine shutdowns, and unaffected by triacetin adhesion.

[0037] This invention discloses a cutting structure for slitting polylactic acid fiber filter rods. The structure is simple to set up, with two cutting blades working together. The middle cutting blade has high hardness to avoid collision with random crystal points in the polylactic acid fiber bundles, which could damage the blade. The side cutting blades protect the middle cutting blade from being stuck by triacetin, and the side cutting blades are detachable for easy replacement. This structure makes the polylactic acid fiber filter rod slitting more efficient and the cutting stability better.

[0038] Example 2, still as Figures 1 to 4As shown, this is only one embodiment of the present invention. Based on Embodiment 1, in the cutting structure for slitting polylactic acid fiber filter rods of the present invention, in order to facilitate the sharpening of the side cutter 2 (i.e., the steel blade), a sharpening head 4 is provided on the outer side of the side cutter 2, so that when the sharpening head 4 sharpens the side cutter 2, the triacetin esters adhering to the side cutter 2 are ground off. Of course, the sharpening head 4 is located on the side of the combined cutting structure away from the polylactic acid fiber bundle 00, such as... Figure 2 As shown.

[0039] It should be noted that the sharpening head 4 will grind away the outer edge of the steel knife, making the blade shorter. If the steel knife is round or ring-shaped, it cannot extend outwards. If sharpening is done, the alloy blade may be exposed and become stuck due to triacetyl esters. In severe cases, the alloy blade will also be sharpened, causing wear. Therefore, for easy sharpening of steel knives, it is best if the steel knife has a structure of long, thin blades.

[0040] That is, the side cutter 2 includes a plurality of blade units 20, and each blade unit 20 extends from the cutter shaft 3 toward the edge of the central cutter 1, such as... Figure 3 As shown, each blade unit 20 is generally elongated, but it is not strictly a rectangular structure. The further away from the cutting axis 3, the wider the blade unit 20 should be, and even the two sides of the blade unit 20 can be appropriately bent.

[0041] Here, the cutting shaft 3 is provided with a blade feeding device 5 for connecting to one end of the blade unit 20 near the cutting shaft 3. The blade feeding device 5 includes a motor 51 located outside the cutting shaft 3, a lead screw 52 coaxially connected to the shaft of the motor 51, and a blade clamp 53 located on the lead screw 52 for connecting to one end of the blade unit 20 near the cutting shaft 3.

[0042] The blade feeding device 5 and the blade unit 20 rotate together with the cutting shaft 3.

[0043] Of course, the blade holder 53 is provided with a lead screw hole for the lead screw 52 to pass through, the lead screw 52 is provided with an external thread on the outside, and the lead screw hole is provided with an internal thread for engaging with the external thread.

[0044] That is, when the inner end of the blade unit 20 is clamped by the blade clamp 53, and the motor 51 drives the lead screw 52 to rotate, the blade clamp 53 and the blade unit 20 extend away from the cutting shaft 3 under the principle of lead screw transmission, which means that the blade unit 20 extends outward.

[0045] Here, the motor 51 is a stepper motor. The steel blade can be set according to its wear condition, that is, according to the grinding coefficient between the blade unit 20 and the grinding head 4, to ensure that the outward extension of the blade unit 20 and the wear between the blade unit 20 and the grinding head 4 are balanced.

[0046] There are many blade units 20. In order for all blade units 20 to extend together, all motors 51 are synchronously controlled so that all blade units 20 extend to the same length at the same time.

[0047] Moreover, each blade unit 20 is generally elongated, but not strictly rectangular. The further away from the cutting axis 3, the wider the blade unit 20 should be. The sides of the blade unit 20 can even be slightly curved, just so that the front ends of multiple blade units 20 can cover the contact position between the alloy blade and the polylactic acid fiber filter rod. The blade unit 20 is not the actual cutting body. The blade unit 20 rotates rapidly under the drive of the cutting axis 3. Therefore, the assembly of the blade units 20 will not affect the cutting quality of the polylactic acid fiber filter rod. It only utilizes the characteristic that the steel blade itself can be sharpened to grind off the triacetin that is stuck to the outside of the cutting blade assembly.

[0048] Of course, a limit block is provided on the lead screw 52. Once the blade clamp 53 abuts against the limit block, it means that the blade unit 20 has reached its maximum outward extension. At this time, it should be indicated that a new blade unit 20 should be replaced. Of course, at this time, the motor 51 needs to rotate in the opposite direction so that the blade clamp 53 reaches the position closest to the cutting shaft 3.

[0049] In addition, a limiting rod 54, parallel to the lead screw 52, ​​is provided between the motor 51 and the blade holder 53. The limiting rod 54 is fixedly mounted on the motor housing of the motor 51. The limiting rod 54 is smoothly arranged, and the blade holder 53 is provided with a limiting rod hole for the limiting rod 54 to pass through. Thus, under the restriction of the limiting rod 54, even if the lead screw 52 rotates, it will not cause the blade unit 20 to rotate. This not only makes the blade unit 20 structurally stable, but also effectively prevents the blade unit 20 from squeezing the side of the intermediate cutter 1.

[0050] Moreover, the limiting rod 54 and the lead screw 52 are located on both sides of the blade unit 20, respectively.

[0051] Finally, a drive motor for driving the cutter shaft 3 to rotate is provided at the end of the cutter shaft 3.

[0052] This invention discloses a cutting structure for slitting polylactic acid fiber filter rods. The structure is simple to set up, with two cutting blades working together. The middle cutting blade has high hardness to avoid collision with random crystal points in the polylactic acid fiber bundles, which could damage the blade. The side cutting blades protect the middle cutting blade from being stuck by triacetin, and the side cutting blades are detachable for easy replacement. This structure makes the polylactic acid fiber filter rod slitting more efficient and the cutting stability better.

[0053] This invention is not limited to the specific embodiments described above, and various modifications and variations are possible. Any modifications, equivalent substitutions, or improvements made to the above embodiments based on the technical essence of this invention should be included within the scope of protection of this invention.

Claims

1. A cutting blade structure for slitting polylactic acid fiber filter rods, characterized in that: It includes a cutting shaft (3) and a cutter set on the cutting shaft (3). The cutter includes a middle cutter (1) and a side cutter (2). The middle cutter (1) is circular, and the blade of the side cutter (2) is flush with the edge of the middle cutter (1). When the cutting shaft rotates, it drives the two cutters to cut the polylactic acid fiber filter rod at the same time. The hardness of the intermediate cutter (1) is higher than that of the side cutter (2), making the intermediate cutter (1) convenient for cutting the crystalline filaments in the polylactic acid fiber filter rod. The side cutter (2) is detachably disposed on the side of the middle cutter (1) to prevent triacetyl ester from adhering to the side of the middle cutter (1) when cutting the polylactic acid fiber filter rod; A grinding head (4) is provided on the outside of the side cutter (2), so that when the grinding head (4) grinds the side cutter (2), the triacetin esters adhering to the side cutter (2) are ground off.

2. The cutting structure for slitting polylactic acid fiber filter rods according to claim 1, characterized in that: The intermediate cutter (1) is an alloy cutter, and the side cutter (2) is a steel cutter.

3. The cutting structure for slitting polylactic acid fiber filter rods according to claim 2, characterized in that: The side cutter (2) includes a plurality of blade units (20), and each blade unit (20) extends from the cutter axis (3) toward the edge of the middle cutter (1).

4. The cutting structure for slitting polylactic acid fiber filter rods according to claim 3, characterized in that: The cutter shaft (3) is provided with a blade feeding device (5) for connecting to one end of the blade unit (20) near the cutter shaft (3). The blade feeding device (5) includes a motor (51) located outside the cutter shaft (3), a lead screw (52) coaxially connected to the shaft of the motor (51), and a blade clamp (53) located on the lead screw (52) for connecting to one end of the blade unit (20) near the cutter shaft (3).

5. The cutting blade structure for slitting polylactic acid fiber filter rods according to claim 4, characterized in that: The motor (51) is a stepper motor.

6. The cutting structure for slitting polylactic acid fiber filter rods according to claim 4, characterized in that: A limiting rod (54) is also provided between the motor (51) and the blade holder (53), which is parallel to the lead screw (52).

7. The cutting structure for slitting polylactic acid fiber filter rods according to claim 6, characterized in that: The limiting rod (54) and the lead screw (52) are located on both sides of the blade unit (20).

8. The cutting structure for slitting polylactic acid fiber filter rods according to claim 2, characterized in that: The number of the side cutters (2) is two.

9. The cutting blade structure for slitting polylactic acid fiber filter rods according to claim 1, characterized in that: The end of the cutter shaft (3) is provided with a drive motor for driving the cutter shaft (3) to rotate.

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