An apparatus and method for manufacturing composite boards made of bamboo fiber and thermoplastic fiber

Abstract

This invention discloses a manufacturing apparatus and method for bamboo fiber and thermoplastic fiber composite boards, belonging to the technical field of natural fiber composite materials. The manufacturing apparatus includes a weighing machine, a bale opener, a loosening machine, a vibrating feeder, a carding machine, a cross-laying machine, a first needle punching machine, a second needle punching machine, and a molding machine. This invention reduces lateral fiber entanglement by adding angle nails and needle gauges during the loosening stage, effectively disrupting the bond between fibers and impurities. During the carding process, gradient beaters are used to achieve gradient carding of bamboo fibers of different lengths, and a cutter is used to control the length of the bamboo fibers. In the needle punching stage, the fiber mixture after lamination is directly needle punched with a thermoplastic film with a designable resin content, allowing for direct molding of bamboo fiber and thermoplastic fiber composite boards with controllable surface resin content. This satisfies the different bonding strength requirements of different materials on both sides of the composite board and can be directly used in the manufacture of interior sandwich structures, eliminating the need for film lamination.

Description

Technical Field

[0001] This invention relates to the field of natural fiber composite materials technology, and in particular to an apparatus and method for manufacturing composite boards made of bamboo fiber and thermoplastic fiber. Background Technology

[0002] Bamboo fiber is a biodegradable fiber that causes no damage to the ecological environment, making it a truly natural and environmentally friendly green fiber. Under the same conditions, bacteria can survive and multiply in cotton and wood fiber products, but their survival ability in bamboo fiber is weak, giving bamboo fiber natural antibacterial and bacteriostatic functions. By preparing bamboo fiber-reinforced composite materials, pollution from plastics and synthetic fibers can be reduced. Currently, bamboo fiber-reinforced composite materials, with their advantages of high specific modulus, specific strength, and convenient processing, have been widely used in automotive interiors, construction, and other fields to replace ordinary engineering plastics and some glass fiber-reinforced resin composite materials.

[0003] Bamboo fiber / thermoplastic fiber composite boards, prepared using bamboo fiber as raw material and thermoplastic fiber as matrix, have advantages such as high strength and good impermeability. Currently, bamboo fiber / thermoplastic fiber composite boards prepared by traditional processes contain many impurities other than bamboo fiber, such as lignin and bamboo powder, resulting in low mechanical properties. Furthermore, the preparation process suffers from problems such as inconsistent bamboo fiber length, uneven dispersion, and easy entanglement, leading to unstable performance of the bamboo fiber / thermoplastic fiber composite boards. Summary of the Invention

[0004] The purpose of this invention is to solve the problems existing in the prior art and to provide an apparatus and method for manufacturing composite boards made of bamboo fiber and thermoplastic fiber.

[0005] To achieve the above-mentioned technical objectives, the technical solution adopted by the present invention is as follows:

[0006] A manufacturing apparatus for bamboo fiber and thermoplastic fiber composite boards includes a weighing machine, a bale opener, an opening machine, a vibrating feeder, a carding machine, a cross-laying machine, a first needle punching machine, a second needle punching machine, and a molding machine connected in sequence.

[0007] The weighing machine is used to weigh bamboo fiber and thermoplastic fiber.

[0008] The unpacking machine is used to loosen the compressed bamboo fiber blocks in the bamboo fiber package into small bundles of bamboo fiber through mechanical impact and tearing, so that the bamboo fiber and thermoplastic fiber are initially mixed.

[0009] The opening machine is used to open and mix bamboo raw fibers and thermoplastic fibers in a preliminary process, remove some of the ultra-short fibers and extra-long fibers in the bamboo raw fibers, remove some woody impurities, and separate fiber bundles.

[0010] Vibrating cotton feeders are used to spread opened and mixed fibers into fiber layers;

[0011] The carding machine is used to repeatedly card and peel the fiber layer, gradually breaking down the fiber bundles in the fiber layer into strip-shaped single fibers to form a mesh fiber layer. The fibers in the mesh fiber layer are initially straightened and have directionality.

[0012] Cross-laying machine is used to stretch a thin layer of mesh fiber, change the fiber arrangement direction in the thin layer of mesh fiber, so that the fiber arrangement that originally had a cross angle is transformed into a fiber arrangement that is evenly distributed in all directions through stretching. Then, the thin layer of mesh fiber with changed fiber arrangement is laid and compacted in sequence to obtain a composite multilayer fiber web of the required thickness and weight.

[0013] The first needle-punching machine is used to fix a layer of thermoplastic needle-punched film onto the lower surface of a composite multilayer fiber mesh by needle punching.

[0014] The second needle punching machine is used to fix a layer of thermoplastic needle punched film onto the surface of the composite multilayer fiber mesh by needle punching, so as to obtain a mixed fiber needle punched composite felt.

[0015] A molding machine is used to mold mixed fiber needle-punched composite felt to obtain a composite board of bamboo fiber and thermoplastic fiber.

[0016] Further improvements to optimize the technical solution include:

[0017] The outlet of the aforementioned opening machine is connected to the opening machine via a conveyor belt. The opening machine includes a coarse opening machine and a fine opening machine. The coarse opening machine is equipped with a rotating coarse striking component. The two sides of the coarse striking component are respectively equipped with angle nails and needle teeth. The two sides of the coarse striking component can tear and loosen the passing fiber mixture, initially removing ultra-short and extra-long fibers as well as some woody impurities. The fine opening machine is equipped with a rotating fine striking component. The surface of the fine striking component is equipped with blades or blades. The blades or blades can strike the passing fiber mixture or simultaneously penetrate the fiber mixture for splitting and combing, further removing ultra-short and extra-long fibers as well as some woody impurities. The inlet of the coarse opening machine is connected to the outlet of the opening machine, the outlet of the coarse opening machine is connected to the inlet of the fine opening machine, and the outlet of the fine opening machine is connected to the vibrating feeder.

[0018] The outlet of the aforementioned fine opening machine is connected to the inlet of the vibrating cotton feeder via a conveying air duct.

[0019] The aforementioned carding machine is equipped with a gradient beater, which includes a gradient conveyor belt. Each gradient of the gradient conveyor belt has a cylinder and a cutter on its upper surface. Several comb needles are distributed at equal intervals or with equal arcs on the cylinder. The comb needles are close to the upper surface of the gradient conveyor belt. The fiber layer entering the carding machine moves on the gradient conveyor belt. When the cylinder rotates, it can drive the comb needles to roll up and comb the fiber layer on the gradient conveyor belt. The cutter is located above the cylinder and can periodically cut down to cut the fibers wrapped around the comb needles, turning long fibers into short fibers with a length within a preset range.

[0020] The distance between adjacent comb needles on different barrels is different, and the distance between adjacent comb needles on the barrel of the next gradient is smaller than the distance between adjacent comb needles on the barrel of the previous gradient.

[0021] The outlet of the aforementioned cross-laying machine is connected to the inlet of the first needle punching machine via a feeding curtain.

[0022] The aforementioned first needle-punching machine includes a lower needle-punching film conveyor belt and a first needle that can move up and down under the drive of a drive cylinder. The lower needle-punching film conveyor belt is used to transport the lower thermoplastic needle-punched film layer. The composite multilayer fiber network and the lower thermoplastic needle-punched film layer are simultaneously fed to the lower part of the first needle. The lower thermoplastic needle-punched film layer is located on the lower surface of the composite multilayer fiber network. The first needle punctures the composite multilayer fiber network and the lower thermoplastic needle-punched film layer in a downward puncture direction, fixing the lower thermoplastic needle-punched film layer on the lower surface of the composite multilayer fiber network to obtain a semi-finished product of mixed fiber needle-punched composite felt.

[0023] The aforementioned second needle-punching machine includes an upper needle-punching film conveyor belt and a second needle that can move up and down under the drive of a drive cylinder. The upper needle-punching film conveyor belt is used to transport the upper thermoplastic needle-punched film layer. The mixed fiber needle-punched composite felt semi-finished product and the upper thermoplastic needle-punched film layer are simultaneously fed to the top of the second needle. The upper thermoplastic needle-punched film layer is located on the upper surface of the mixed fiber needle-punched composite felt semi-finished product. The second needle punctures the mixed fiber needle-punched composite felt semi-finished product and the upper thermoplastic needle-punched film layer in an upward puncture direction, fixing the upper thermoplastic needle-punched film layer on the surface of the composite multilayer fiber mesh to obtain the mixed fiber needle-punched composite felt.

[0024] A method for manufacturing a bamboo fiber and thermoplastic fiber composite board, using the aforementioned bamboo fiber and thermoplastic fiber composite board manufacturing apparatus, specifically includes the following steps:

[0025] Step 1: Weigh the degummed bamboo fibers and thermoplastic fibers according to the ratio using a weighing machine, and feed them into a bag opener at the same time. The bag opener loosens the tightly compressed bamboo fiber blocks in the bamboo fiber bag into small bamboo fiber bundles through mechanical impact and tearing, so that the bamboo fibers and thermoplastic fibers are initially mixed.

[0026] Step 2: The preliminarily mixed bamboo fiber and thermoplastic fiber are fed into the opening machine via a conveyor belt to open and mix, removing some of the ultra-short fibers and extra-long fibers in the bamboo fiber, while removing some woody impurities and separating the fiber bundles.

[0027] Step 3: After opening, the mixed fibers are fed into the vibrating cotton feeder through the conveying air duct and spread into a relatively uniform fiber layer of equal thickness and width.

[0028] Step 4: The fiber layer is fed into the carding machine. The gradient beaters repeatedly card, peel and cut the fibers in the fiber layer, gradually decomposing the fiber bundle into strip-shaped single fibers with a length within the preset range. The strip-shaped single fibers form a mesh fiber layer. The fibers in the mesh fiber layer are initially straightened and have directionality.

[0029] Step 5: The thin layer of mesh fiber is fed into the cross-laying machine. The cross-laying machine stretches the thin layer of mesh fiber, changing the fiber arrangement direction. The fiber arrangement with cross angles is transformed into a fiber arrangement that is evenly distributed in all directions through stretching, so as to control the weight of the fiber web and improve the longitudinal and transverse strength ratio of the fiber web. Then, the thin layer of mesh fiber with changed fiber arrangement is laid and compacted in sequence to obtain a composite multilayer fiber web with the required thickness and weight.

[0030] Step Six: A thermoplastic needle-punched film layer is needle-punched on the lower surface of the composite multilayer fiber web using a first needle-punching machine, and a thermoplastic needle-punched film layer is needle-punched on the upper surface of the composite multilayer fiber web using a second needle-punching machine, to obtain a mixed fiber needle-punched composite felt; both the needles of the first and second needle-punching machines are equipped with hooks, which drive the fibers on the surface and inside of the composite multilayer fiber web to move from the planar direction to the vertical direction, thereby increasing the strength and density of the composite multilayer fiber web, while simultaneously fixing the upper and lower thermoplastic needle-punched film layers;

[0031] Step 7: Put the mixed fiber needle-punched composite felt into the molding machine. The molding machine uses a hot pressing process to mold the mixed fiber needle-punched composite felt. Low pressure preheating, timed constant temperature and pressure are used, and the pressure is maintained to cool and shape until room temperature is reached and the board is taken out to obtain a composite board of bamboo fiber and thermoplastic fiber.

[0032] The upper thermoplastic needle-punched film layer and the lower thermoplastic needle-punched film layer are made of polyester fiber, nylon fiber or polypropylene fiber.

[0033] Compared with the prior art, the present invention has the following beneficial effects:

[0034] 1. This invention achieves uniform dispersion of bamboo fibers by using a gradient beater to perform gradient combing, and achieves uniformity of bamboo fiber length by using a cutter to control the length of bamboo fibers, which greatly improves the performance stability of bamboo fiber and thermoplastic fiber composite board.

[0035] 2. This invention utilizes the needle-punching process to enhance the strength and density of the composite multilayer fiber web while simultaneously fixing the upper and lower thermoplastic needle-punched film layers. It eliminates the need for laminating the needle-punched film, solving the problem of cumbersome processes in combining bamboo fiber and thermoplastic fiber composite boards with different materials. By selectively controlling the content of the thermoplastic needle-punched film layer, a bamboo fiber and thermoplastic fiber composite board with controllable surface resin content can be obtained after molding, enabling subsequent bonding with different materials and meeting the varying adhesion strength requirements of the bamboo fiber and thermoplastic fiber composite board for different materials on both sides.

[0036] 3. In this invention, a coarse opening machine and a fine opening machine are set up in the opening process. The coarse opening machine adds corner nails and needle teeth to reduce the lateral entanglement of bamboo raw fibers and fully destroy the connection between bamboo raw fibers and impurities, so as to achieve preliminary impurity removal in the front stage. The fine opening machine uses blades or blades to divide and comb the fibers, loosening the fiber blocks into smaller pieces, so as to achieve further impurity removal in the front stage, which facilitates subsequent processing and reduces the impurity content of bamboo raw fiber and thermoplastic fiber composite board. Attached Figure Description

[0037] Figure 1 This is a schematic diagram of an apparatus for manufacturing composite boards made of bamboo fiber and thermoplastic fiber.

[0038] The attached diagram is labeled as follows: 1. Weighing machine; 2. Opening machine; 3. Conveyor belt; 4. Coarse opening machine; 5. Coarse striking machine; 6. Fine opening machine; 7. Conveying duct; 8. Vibrating feeder; 9. Cutter; 10. Gradient beater; 11. Carding machine; 12. Cross-laying machine; 13. Feeding curtain; 14. Lower needle-punching film laying conveyor belt; 15. First needle; 16. First needle-punching machine; 17. Second needle-punching machine; 18. Upper needle-punching film laying conveyor belt; 19. Molding machine; 20. Gradient conveyor belt; 21. Cylinder; 22. Carding needle; 23. Second needle. Detailed Implementation

[0039] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments.

[0040] Unless otherwise defined, the technical or scientific terms used in this invention shall have the ordinary meaning as understood by one of ordinary skill in the art to which this invention pertains.

[0041] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention, and no reference numerals in the claims should be construed as limiting the scope of the claims.

[0042] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can be appropriately combined to form other embodiments that can be understood by those skilled in the art. These other embodiments are also covered within the scope of protection of this invention.

[0043] It should also be understood that the specific embodiments described above are only used to explain the present invention, and the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

[0044] Techniques, methods, and apparatus known to those skilled in the art may not be discussed in detail, but where appropriate, they should be considered part of the specification.

[0045] All prior art documents cited in this specification are incorporated herein by reference in their entirety and are therefore part of the disclosure of this invention.

[0046] This invention designs a manufacturing apparatus and method for bamboo fiber and thermoplastic fiber composite boards. Compared with the prior art, this invention can reduce the lateral entanglement of bamboo fibers, fully destroy the connection between fibers and impurities, achieve pre-process impurity removal, and solve the problems of bamboo fibers being of different lengths, having large dimensional deviations, and being prone to entanglement. It obtains bamboo fiber and thermoplastic fiber composite boards with controllable surface resin adhesive, meeting the different bonding strength requirements of different materials on both sides of the composite board. It can be directly used in the manufacturing of interior sandwich structures, eliminating the need for the lamination process of needle-punched film.

[0047] The present invention adopts the following technical solution:

[0048] like Figure 1 As shown, an apparatus for manufacturing composite boards of bamboo fiber and thermoplastic fiber includes a weighing machine 1, a bale opener 2, an opening machine, a vibrating feeder 9, a carding machine 12, a cross-laying machine 13, a first needle punching machine 17, a second needle punching machine 18, and a molding machine 20 connected in sequence.

[0049] Weighing machine 1 conveys the fiber bale mixture via a horizontal conveyor curtain;

[0050] The fiber opening machine is fed with the fiber to be opened via a conveyor belt;

[0051] The vibrating cotton feeder 9 is connected to the opening machine via the conveying air duct 8;

[0052] The carding machine 12 is fed with opened fibers evenly by the vibrating feeder 9 via a conveyor belt;

[0053] The cross-laying machine 13 feeds in the carded fiber web via a conveyor belt, and the feeding curtain 14 is connected to the needle punching machine to transport the composite multi-layer fiber web.

[0054] The opening machine includes a coarse opening machine 4 and a fine opening machine 6;

[0055] In the coarse opening process, the two surfaces of the coarse impact component 5 of the coarse opening machine 4 are equipped with angle nails and needle teeth that move relative to each other to tear and loosen the fiber blocks in the raw material. The fibers are displaced to a certain extent, making it easier to separate impurities. This avoids incomplete opening caused by the different lengths of bamboo fibers, reduces the transverse entanglement of fibers, fully destroys the connection between fibers and impurities, removes ultra-short and extra-long fibers, and achieves pre-process impurity removal.

[0056] In the fine opening process, the blades and vanes on the high-speed rotating fine impacting parts 7 of the fine opening machine 6 strike the fed fiber mixture or simultaneously penetrate the fiber layer to divide and comb it, thereby breaking the bonding force between fibers and between fibers and impurities, so as to further loosen the fiber blocks and remove impurities, and break the fiber blocks into smaller pieces.

[0057] The carding machine 12 uses gradient beaters 11 to achieve gradient carding of bamboo raw fibers of different lengths, and uses cutters 10 to control the length of bamboo raw fibers, resulting in good web quality and the ability to card into fiber webs with uniform thickness and length.

[0058] The needle plate of the needle punching machine has densely arranged needles with barbs. When multiple needles penetrate the composite multilayer fiber web, the barbs on the needles drive the fibers on the surface and subsurface of the fiber web to move from the plane direction of the fiber web to the vertical direction of the fiber web. This causes the fibers to shift up and down, detach from the barbs, and remain in the fiber web. The strength and density of the fiber web increase, and the fiber web forms a mixed fiber needle-punched composite felt with certain strength, density, and elasticity properties.

[0059] The composite board obtained by molding has different resin adhesion on both sides, which meets the different adhesion strength requirements of different materials on both sides of the composite board, and can be directly used in the manufacture of interior sandwich structures.

[0060] The present invention will be further illustrated by a specific embodiment below.

[0061] A method for manufacturing a composite board of bamboo fiber and thermoplastic fiber, comprising the following specific steps:

[0062] Step 1: Unpacking and mixing. The degummed bamboo fibers and polypropylene short fibers are weighed by weighing machine 1 according to the optimal ratio of 60% bamboo fibers and 40% polypropylene short fibers. At the same time, they are fed into unpacking machine 2. The bamboo fiber blocks that are compressed in the bamboo fiber package are loosened into small bamboo fiber bundles by mechanical impact and tearing, so that the bamboo fibers and polypropylene short fibers are initially mixed.

[0063] Step 2: Opening. The conveyor belt feeds the unpacked fibers into the opening machine for further opening and mixing. The two surfaces of the coarse impact mechanism of the opening machine are equipped with angle nails and needle teeth, which move relative to each other to tear and loosen the fiber blocks in the raw material, remove some of the ultra-short fibers and extra-long fibers in the bamboo raw fiber, and improve the length, fineness and uniformity of the reinforcing bamboo raw fiber.

[0064] Step 3: Evenly feed cotton, loosen the fibers and feed them into the vibrating cotton feeder 9 through the conveying air duct 8, and spread them into a relatively uniform fiber layer of equal thickness and width.

[0065] Step 4: The vibrating feeder 9 feeds the carding machine 12 evenly, and the gradient beater 11 repeatedly combs and peels the fibers, gradually breaking down the fiber bundles into strip-shaped single fibers, forming a thin layer of mesh fibers. The fibers are initially straightened and have directionality.

[0066] This invention uses bamboo fiber and polypropylene short fiber to be opened and mixed and carded at the same time. The fibers are evenly distributed after mixing and carding, and the distribution of bamboo fiber in the matrix is ​​more regular, so that the bending strength and bending modulus of the composite felt are significantly higher than those of the separately opened and mixed carded fibers.

[0067] Step 5: Cross-laying the web. The cross-laying machine 13 stretches the combed web by cross-folding through the moving mechanism, changing the fiber arrangement direction. The fiber arrangement with a certain cross angle is transformed into a fiber arrangement that is evenly distributed in all directions through stretching, so as to control the weight of the web and improve the longitudinal and transverse strength ratio of the web, and obtain a composite multilayer fiber web with the required thickness and weight.

[0068] Step 6: Pre-punching. The first needle punching machine 17 punches the composite multilayer fiber web from top to bottom. The needles on the needles drive the fibers on the surface and subsurface of the web to move from the plane of the web to the vertical direction of the web, thereby increasing the strength of the web and obtaining a single-layer fiber web with a certain elasticity and strength, preventing the direction of the web fibers from changing during the subsequent preparation process.

[0069] Step 7: Main needle punching, the second needle punching machine punches from bottom to top, further reinforcing the web-laying fibers to form a structurally stable mixed fiber needle-punched composite felt, improving wear resistance and strength, optimizing the adhesive film lamination process required when the product is laminated with other materials in the later stage, and improving its interface bonding strength with automotive interior parts.

[0070] Step 8: Compression molding. The mixed fiber needle-punched composite felt is compressed using a hot pressing process. Low-pressure preheating, timed constant-temperature pressurization, and pressure cooling and shaping are carried out until room temperature is reached to obtain bamboo fiber reinforced polypropylene short fiber composite board products.

[0071] The above are merely preferred embodiments of the present invention. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions falling within the scope of the present invention's concept are within the scope of protection of the present invention. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principles of the present invention should be considered within the scope of protection of the present invention.

Claims

1. A device for manufacturing composite boards of bamboo fiber and thermoplastic fiber, characterized in that, The system includes a weighing machine (1), a bale opener (2), a loosening machine, a vibrating cotton feeder (9), a carding machine (12), a cross-laying machine (13), a first needle punching machine (17), a second needle punching machine (18), and a molding machine (20), connected in sequence. The weighing machine (1) is used to weigh bamboo fiber and thermoplastic fiber. The opening machine (2) is used to loosen the compressed bamboo fiber blocks in the bamboo fiber package into small bamboo fiber bundles by mechanical impact and tearing, so that the bamboo fiber and thermoplastic fiber are initially mixed. The opening machine is used to open and mix the initially mixed bamboo fibers and thermoplastic fibers, remove some of the ultra-short fibers and extra-long fibers in the bamboo fibers, and at the same time remove some woody impurities and separate the fiber bundles. The vibrating cotton feeder (9) is used to spread the opened and mixed fibers into a fiber layer; The carding machine (12) is used to repeatedly card and peel the fiber layer, gradually decompose the fiber bundles in the fiber layer into strip-shaped single fibers, form a mesh fiber thin layer, and the fibers in the mesh fiber thin layer are initially straightened and have directionality; The cross-laying machine (13) is used to stretch the mesh fiber thin layer, change the fiber arrangement direction in the mesh fiber thin layer, so that the fiber arrangement with the original cross angle is transformed into a fiber arrangement evenly distributed in all directions through stretching. Then the mesh fiber thin layer with the changed fiber arrangement is laid and compacted in sequence to obtain a composite multilayer fiber web with the required thickness and weight. The first needle punching machine (17) is used to fix a layer of thermoplastic needle punched film onto the lower surface of the composite multilayer fiber network by needle punching. The second needle punching machine (18) is used to fix a layer of thermoplastic needle punched film onto the surface of the composite multilayer fiber mesh by needle punching, so as to obtain a mixed fiber needle punched composite felt; The molding machine (20) is used to mold the mixed fiber needle-punched composite felt to obtain a composite board of bamboo fiber and thermoplastic fiber; the carding machine (12) is equipped with a gradient beater (11), the gradient beater (11) includes a gradient conveyor belt (21), each gradient of the gradient conveyor belt (21) has a cylinder (22) and a cutter (10) on its upper surface, the cylinder (22) has a number of comb needles (23) distributed at equal intervals or equal arcs, the comb needles (23) are close to the upper surface of the gradient conveyor belt (21), the fiber layer entering the carding machine (12) moves on the gradient conveyor belt (21); the distance between adjacent comb needles (23) on different cylinders (22) is different, and the distance between adjacent comb needles (23) on the cylinder (22) of the next gradient is smaller than the distance between adjacent comb needles (23) on the cylinder (22) of the previous gradient.

2. The apparatus for manufacturing composite boards of bamboo fiber and thermoplastic fiber according to claim 1, characterized in that, The outlet of the opening machine (2) is connected to the loosening machine via a conveyor belt (3). The loosening machine includes a coarse loosening machine (4) and a fine loosening machine (6). The coarse loosening machine (4) is equipped with a rotatable coarse striking component (5). The two sides of the coarse striking component (5) are respectively equipped with angle nails and needle teeth. The two sides of the coarse striking component (5) can tear and loosen the fiber mixture passing through, initially removing ultra-short and extra-long fibers and initially removing some wood impurities. The fine loosening machine (6) is equipped with a rotatable coarse striking component (5). The fine beating machine (7) is provided with blades or blades on its surface. The blades or blades can strike the fiber mixture or simultaneously penetrate the fiber mixture to divide and comb it, further removing ultra-short and extra-long fibers and further removing some wood impurities. The inlet of the coarse opener (4) is connected to the outlet of the opening machine (2), the outlet of the coarse opener (4) is connected to the inlet of the fine opener (6), and the outlet of the fine opener (6) is connected to the vibrating cotton feeder (9).

3. The apparatus for manufacturing composite boards of bamboo fiber and thermoplastic fiber according to claim 2, characterized in that, The outlet of the fine opening machine (6) is connected to the inlet of the vibrating cotton feeder (9) through the conveying air duct (8).

4. The apparatus for manufacturing composite boards of bamboo fiber and thermoplastic fiber according to claim 2, characterized in that, When the cylinder (22) rotates, it can drive the comb needle (23) to roll up and comb the fiber layer on the gradient conveyor belt (21). The cutter (10) is set above the cylinder (22). The cutter (10) can periodically cut down and cut the fiber wrapped on the comb needle, so that the long fiber becomes short fiber with a length within the preset range.

5. The apparatus for manufacturing composite boards of bamboo fiber and thermoplastic fiber according to claim 4, characterized in that, The outlet of the cross-laying machine (13) is connected to the inlet of the first needle punch (17) via a feeding curtain (14).

6. The apparatus for manufacturing a composite board of bamboo fiber and thermoplastic fiber according to claim 5, characterized in that, The first needle punching machine (17) includes a lower needle punching film conveying belt (15) and a first needle (16) that can move up and down under the drive of a drive cylinder. The lower needle punching film conveying belt (15) is used to transport the lower thermoplastic needle punching film layer. The composite multilayer fiber network and the lower thermoplastic needle punching film layer are simultaneously delivered to the lower part of the first needle (16). The lower thermoplastic needle punching film layer is located on the lower surface of the composite multilayer fiber network. The first needle (16) pierces the composite multilayer fiber network and the lower thermoplastic needle punching film layer. The piercing direction is from top to bottom, fixing the lower thermoplastic needle punching film layer on the lower surface of the composite multilayer fiber network to obtain a semi-finished product of mixed fiber needle punched composite felt.

7. The apparatus for manufacturing composite boards of bamboo fiber and thermoplastic fiber according to claim 6, characterized in that, The second needle punching machine (18) includes an upper needle punching film conveying belt (19) and a second needle (24) that can move up and down under the drive of a drive cylinder. The upper needle punching film conveying belt (19) is used to transport the upper thermoplastic needle punching film layer. The mixed fiber needle punching composite felt semi-finished product and the upper thermoplastic needle punching film layer are simultaneously fed to the upper surface of the second needle (24). The upper thermoplastic needle punching film layer is located on the upper surface of the mixed fiber needle punching composite felt semi-finished product. The second needle (24) pierces the mixed fiber needle punching composite felt semi-finished product and the upper thermoplastic needle punching film layer. The piercing direction is from bottom to top, fixing the upper thermoplastic needle punching film layer on the surface of the composite multilayer fiber mesh to obtain the mixed fiber needle punching composite felt.

8. A method for manufacturing a composite board of bamboo fiber and thermoplastic fiber, characterized in that, The application of the bamboo fiber and thermoplastic fiber composite board manufacturing apparatus as described in claim 7 specifically includes the following steps: Step 1: Weigh the degummed bamboo fiber and thermoplastic fiber according to the ratio using a weighing machine (1) and feed them into a pack opener (2). The pack opener (2) loosens the compressed bamboo fiber blocks in the bamboo fiber pack into small bamboo fiber bundles by mechanical impact and tearing, so that the bamboo fiber and thermoplastic fiber are initially mixed. Step 2: The preliminarily mixed bamboo fiber and thermoplastic fiber are fed into the opening machine via conveyor belt (3) to open and mix, remove some of the ultra-short fibers and extra-long fibers in the bamboo fiber, and at the same time remove some woody impurities and separate the fiber bundles; Step 3: After opening, the mixed fibers are fed into the vibrating cotton feeder (9) through the conveying air duct (8) and spread into a relatively uniform fiber layer of equal thickness and width. Step 4: The fiber layer is put into the carding machine (12), and the gradient beater (11) repeatedly cardes, peels and cuts the fiber layer, gradually decomposing the fiber bundle into strip-shaped single fibers with a length within the preset range. The strip-shaped single fibers form a mesh fiber thin layer. The fibers in the mesh fiber thin layer are initially straightened and have directionality. Step 5: The thin layer of mesh fiber is fed into the cross-laying machine (13). The cross-laying machine (13) stretches the thin layer of mesh fiber, changes the fiber arrangement direction, and the fiber arrangement with cross angle is transformed into a fiber arrangement that is evenly distributed in all directions through stretching, so as to control the weight of the fiber web and improve the longitudinal and transverse strength ratio of the fiber web. Then the thin layer of mesh fiber with changed fiber arrangement is laid and compacted in sequence to obtain a composite multilayer fiber web with the required thickness and weight. Step 6: A thermoplastic needle-punched film layer is needle-punched on the lower surface of the composite multilayer fiber network using the first needle-punching machine (17), and a thermoplastic needle-punched film layer is needle-punched on the upper surface of the composite multilayer fiber network using the second needle-punching machine (18) to obtain a mixed fiber needle-punched composite felt; both the needles of the first needle-punching machine (17) and the second needle-punching machine (18) are equipped with barbs, which drive the fibers on the surface and inside of the composite multilayer fiber network to move from the planar direction to the vertical direction, thereby increasing the strength and density of the composite multilayer fiber network, while simultaneously fixing the upper and lower thermoplastic needle-punched film layers; Step 7: Put the mixed fiber needle-punched composite felt into the molding machine (20). The molding machine (20) uses hot pressing process to mold the mixed fiber needle-punched composite felt. Low pressure preheating, timed constant temperature pressurization, and pressure cooling and shaping are carried out until room temperature is reached to obtain bamboo fiber and thermoplastic fiber composite board.

9. A method for manufacturing a composite board of bamboo fiber and thermoplastic fiber according to claim 8, characterized in that, The upper thermoplastic needle-punched film layer and the lower thermoplastic needle-punched film layer are made of polyester fiber, nylon fiber or polypropylene fiber.

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