Co-extrusion composite production line for preparing special root blocking film for straw matrix disc

Abstract

The utility model relates to the technical field of co-extrusion equipment, and provides a co-extrusion composite production line for preparing a root resisting film special for a straw matrix disc, and the co-extrusion composite production line comprises an uncoiling device, a steering device, a melt layering composite device, a film spraying device, a composite device, a punching device and a coiling device which are mounted through a main rack; the melt layering and compounding device comprises a feeding square block, a converging square block and an extruding square block; the feeding square block comprises a feeding square block body, a plurality of functional melt flow channels are arranged in the feeding square block body, each functional melt flow channel comprises a feeding section, a flow stabilizing section and a flow smoothing section which are communicated in sequence, the feeding sections of the functional melt flow channels form feeding ports in the feeding square block body, and the flow stabilizing sections of the functional melt flow channels are communicated with the flow smoothing sections of the functional melt flow channels. The advection sections of the multiple functional melt runners are arranged in a stacked mode in the z-axis direction. The composite lamination material can be obtained through the extrusion device, the composite lamination material and the base paper can be compounded through one-time lamination, and the production efficiency is high.

Description

Technical Field

[0001] The present application relates to the technical field of co-extrusion equipment, and specifically to a production line for preparing a special root barrier film for a composite straw matrix disc by means of co-extrusion. Background Art

[0002] The straw matrix tray is a block-shaped seedling material. The raw materials are mostly rice, corn, wheat and other crop straws. The common processes include high-temperature composting and molding. The straw matrix tray can replace the traditional nutrient soil, reduce the heavy labor loss in the soil collection process, and avoid the color pollution problem of the existing plastic seedling tray.

[0003] However, in the actual operation of raising seedlings in the field, the straw matrix tray of the prior art still needs to be used in conjunction with the plastic seedling tray, otherwise the roots of the seedlings cultivated in the bottom of the straw matrix tray will grow into the soil and take root therein, resulting in the situation that the seedlings cannot be raised or the seedlings are rolled up. The situation that the seedlings are difficult to raise or the seedlings are rolled up easily causes the straw matrix tray to be damaged, which seriously affects the use of the straw matrix tray.

[0004] In response to this problem, Chinese invention patent CN202211173291.5 provides a method for preparing a degradable film for preventing root penetration for rice seedling raising straw substrate trays without seedling trays. A degradable polymer is coated on straw paper to form a degradable film for preventing root penetration with high tear index, high burst resistance, and high tensile index, which can be returned to the field for degradation after use. Chinese invention patent CN202211651355.8 provides a composite root barrier film for straw substrate trays and its preparation method and application. A root barrier layer for preventing root penetration and a barrier layer for preventing moisture and acid-base penetration are coated on both sides of the substrate paper, and the design of folded edges and cross bars can avoid the problem of intertwining and entanglement of seedling roots in adjacent straw substrate trays and seeds falling into gaps.

[0005] Although the aforementioned paper-based or polymer-based root barrier films serve the purpose of blocking the roots of the seedlings in the straw matrix tray in different ways, both are currently processed by traditional laminating machines. Laminating machines, also known as extrusion laminating machines, are a type of extrusion molding, with many advantages such as fast production speed, cost saving and labor saving.

[0006] However, with the update of root barrier film technology, the current root barrier film is often composed of more than two functional layers, such as a root barrier film composed of a strength layer that hinders root penetration, a slow-release layer that promotes root growth, and an adhesive layer between the paper base and the surface layer. When using a traditional laminating machine to produce a composite root barrier film, it is necessary to laminate multiple times to obtain the corresponding functional layers, which greatly reduces production efficiency. Utility Model Content

[0007] In order to solve the problem that the existing traditional laminating machine needs multiple laminating processes to prepare a root barrier film with multiple functional coatings, the present application proposes a co-extrusion composite production line for preparing a special root barrier film for straw matrix discs, and designs the traditional laminating extruder head into a multi-layer co-extrusion composite extruder head including a melt layering composite device, a laminating device and a composite device. Among them, the melt layering composite device can flow into a variety of melts with different functions according to functional needs, and the melt becomes a layered fluid during the flow process, and the multiple layered fluids are stacked on each other to extrude a composite functional laminating material, and the composite functional laminating material has the same width and thickness as the predetermined composite functional layer; then, the laminating device provides the composite functional laminating material as a whole to the surface of the base paper, and under the action of the composite device, the composite functional laminating material solidifies to form a composite functional layer. The composite functional layer includes different functional layers formed by solidification of different melts, achieving the technical purpose of obtaining a composite functional layer with different functional layers by one laminating, solving the technical problem that the prior art requires multiple laminating processes to achieve, and improving production efficiency.

[0008] The present application provides a co-extrusion composite production line for preparing a special root barrier film for a straw matrix disk, comprising a main frame, and an unwinding device, a steering device, a melt layering composite device, a laminating device, a composite device, a punching device and a winding device installed through the main frame;

[0009] The melt layered compounding device comprises a feed block, a confluence block and an extrusion block;

[0010] The feed block comprises a feed block body, a plurality of functional melt flow channels are arranged in the feed block body, the functional melt flow channels comprise a feed section, a steady flow section and a flat flow section which are connected in sequence, the feed sections of the plurality of functional melt flow channels respectively form feed ports on the feed block body, and the flat flow sections of the plurality of functional melt flow channels are stacked along the z-axis direction;

[0011] The confluence block comprises a confluence block body, in which a main flow channel is arranged, the main flow channel is connected with the flat flow section located at the bottom layer, and the other flat flow sections are sequentially converged downward into the main flow channel through the confluence bends in order from bottom to top, and the flow channel height of the main flow channel increases after each confluence bend is connected with the confluence bend;

[0012] The extrusion block includes an extrusion block body, in which an extrusion flow channel is arranged, and the end of the extrusion flow channel forms an extrusion port on the extrusion block body. The extrusion flow channel is connected to the main flow channel, and the flow channel width of the extrusion flow channel gradually increases and the flow channel height gradually decreases.

[0013] Preferably, according to the flow direction, the flow stabilization section is vertically arranged along the z-axis direction, and the flow leveling section is horizontally arranged along the x-axis direction.

[0014] As a further preference, the steady flow section comprises a fan-shaped channel, the fan-shaped upper portion of which is connected to the feed section, and the fan-shaped lower portion of which is connected to the horizontal flow section in a bent manner.

[0015] Preferably, the flow channel height of the fan-shaped upper part of the flow stabilizing section is greater than the flow channel height of the fan-shaped lower part thereof.

[0016] As a further preference, compared with the flow channel height of the fan-shaped upper part of the flow stabilizing section, the flow channel height of the fan-shaped lower part thereof is 45% to 50% of the initial flow channel height.

[0017] Preferably, the horizontal flow section is connected to the bend through a flow expansion section, and along the flow direction, the flow channel width of the flow expansion section gradually increases and the flow channel height gradually decreases.

[0018] Preferably, the laminating device includes a guide head docked and assembled with the extrusion port, and a steering feed roller docked and matched with the guide head; the guide head includes a guide head body, a drainage channel is provided in the guide head body, the drainage channel includes a connecting section, an outflow section, and an arc transition section connecting the connecting section and the outflow section, the connecting section is connected to the extrusion channel and is horizontally arranged along the x-axis direction, the outflow section is inclined downward, and has an angle of 5°~10° with the horizontal plane, and a flow outlet is formed on the guide head body.

[0019] As a further preference, the guiding outer facade of the guide head body having the outflow outlet is an inclined surface with an inclination angle of 15° to 20°, and the roller surface of the steering feed roller is linearly abutted against the guiding outer facade, and the abutment point is located below the outflow outlet.

[0020] As a further preference, the roller radius of the steering feed roller is 10 cm to 15 cm.

[0021] As a further preference, the steering device supplies the base paper to the bottom of the steering feed roller and there is a certain gap between the base paper and the steering feed roller; when the base paper passes under the steering feed roller, the base paper tilts downward by 3°~5°.

[0022] Preferably, the punching device is a thermal puncher.

[0023] In summary, the present application provides a co-extrusion composite production line for preparing a special root barrier film for straw matrix discs, which can form a composite coating material having multiple stacked fluid layers with different functions on the surface of the base paper in a single coating device, and further obtain a root barrier film through a composite device. The prepared root barrier film has multiple functional layers, so that the production line of the present application has higher production efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without paying any creative labor.

[0025] Figure 1 A schematic structural diagram of a co-extrusion composite production line for preparing a special root barrier film for a straw matrix disk provided in an embodiment of the present application.

[0026] Figure 2 for Figure 1 A partial enlarged view of point B in the middle.

[0027] Figure 3 A schematic diagram of the structure of a melt layering and compounding device provided in an embodiment of the present application.

[0028] Figure 4 A structural explosion diagram of the melt layering composite device provided in an embodiment of the present application.

[0029] Figure 5 for Figure 3 Section view in the AA direction.

[0030] Figure 6 A schematic diagram of the structure of a coating device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0031] In order to enable those skilled in the art to better understand the technical solutions in the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of this application.

[0032] Reference Figure 1-Figure 6 A co-extrusion composite production line for preparing a special root barrier film for straw matrix discs is shown, which includes a main frame, and an unwinding device 1, a steering device 2, a melt layering composite device 3, a coating device 4, a composite device 5, a punching device 6 and a winding device 7 installed on the main frame. The above devices 1-7 can be a complete production line installed on the same main frame, or they can be independent devices with frames respectively, and only the above sequence is satisfied in the production process.

[0033] The unwinding device 1 unwinds the roll of base paper 8 and conveys the base paper 8 in the positive direction along the x-axis. The steering device 2 further conveys the base paper 8 and enables the base paper 8 to have an angle, flatness and tension suitable for coating. The melt-layered composite device 3 co-extrudes a plurality of functional melts to form a composite coating material 9 having a plurality of functional fluid layers. The coating device 4 provides the composite coating material 9 extruded from the melt-layered composite device 3 to the surface of the substrate 8. The composite device 5 can solidify the composite coating material 9 into a composite functional layer 9' on the surface of the substrate 8, thereby obtaining a root barrier film 10. The punching device 6 forms an array of perforations on the root barrier film 10. The winding device 7 winds up the root barrier film 10 for transportation and / or storage.

[0034] The unwinding device 1 and the steering device 2 may be any feasible structure in the prior art, such as a combination of an unwinding machine and a steering roller unit.

[0035] The melt layering compounding device 3 comprises a feed block 31, a converging block 32 and an extrusion block 33 which are sequentially connected and fixedly coupled.

[0036] The feed block 31 includes a feed block body 311, and a plurality of functional melt flow channels are arranged in the feed block body 311. According to the flow sequence of the functional coating, the functional melt flow channel includes a feed section, a steady flow section and a flat flow section connected in sequence. The number of functional melt flow channels can be determined according to the number of functional layers required in the composite functional layer.

[0037] The flow channel of the feed section is in the shape of a tubular channel. The feed section is arranged vertically (in the z-axis direction), or at least arranged vertically inclined, that is, the melt can flow downward in the feed section and form a fluid. One end of the feed section forms a feed port on the feed block body 311, and the other end is connected to the steady flow section. The flow channel of the steady flow section is in the shape of a fan-shaped channel with a fan-shaped arc surface facing upward, and the steady flow section is arranged vertically, that is, the fluid can flow downward in the steady flow section. The upper part of the steady flow section is connected to the feed section, and the shape of the connecting port is the flow channel cross-sectional shape of the feed port. The lower part of the steady flow section is connected to the flat flow section through a 90° turning bend, so in fact, the flat flow section is a bent extension flow channel of the flat flow section. The flat flow section is arranged horizontally (in the x-axis direction), that is, the fluid flows horizontally along the x-axis direction in the flat flow section. Preferably, the fluid flows in the opposite direction along the x-axis in the flat flow section.

[0038] In order to further achieve the effect of steady flow, the height of the flow channel in the fan-shaped upper part of the steady flow section is greater than the height of the flow channel in the fan-shaped lower part. In other words, along the flow direction of the fluid, the flow channel of the steady flow section gradually widens, but the flow channel height gradually decreases. Specifically, compared with the flow channel height of the fan-shaped upper part of the steady flow section, the flow channel height of the fan-shaped lower part is 45% to 50% of the height of the initial flow channel (i.e., the fan-shaped upper part), and the initial flow channel height is the same as the flow channel diameter of the feed section. Preferably, the fan-shaped surface of the steady flow section is a straight slope, and the steady flow section is a symmetrical structure. Of course, making the fan-shaped surface an arc surface is also a feasible solution.

[0039] Those skilled in the art can understand that the flow channel height of the steady flow section is its dimension in the x-axis direction, while the flow channel height of the flat flow section is its dimension in the z-axis direction.

[0040] The confluence block 32 includes a confluence block body 321, in which a main flow channel 322 is provided. The main flow channel 322 is arranged horizontally (in the x-axis direction), that is, the fluid flows horizontally in the main flow channel 322 in the opposite direction along the x-axis. The main flow channel 322 is connected to the flat flow section located at the bottom layer, so it is actually a horizontal extension flow channel of the flat flow section located at the bottom layer. The flat flow sections of other functional melt flow channels are sequentially converged downward into the main flow channel 322 through the confluence bend in order from bottom to top, and the flow channel height of the main flow channel 322 increases after each confluence bend is connected.

[0041] By using the converging bend to make the horizontal flow section of the functional coating flow channel located above converge from top to bottom into the main flow channel 322, it can better ensure that the functional coating above is more evenly coated on the functional coating below, thereby obtaining each functional fluid layer with uniform texture.

[0042] Preferably, in order to initially extend and reduce the thickness of the composite coating material, the flat flow section is connected to the expansion section, and along the flow direction, the flow channel width of the expansion section gradually increases and the flow channel height gradually decreases. Preferably, the flow channel width of the expansion section is 1.5 to 2 times the initial flow channel width, and the flow channel height is 45% to 50% of the initial flow channel height. The flat flow section at the bottom layer is directly connected to the main channel 322 through the expansion section, and the expansion section connected to other flat flow sections merges into the main channel 322 through the converging bend.

[0043] The extrusion block 33 includes an extrusion block body 331, in which an extrusion flow channel 332 is provided, and the end of the extrusion flow channel 332 forms an extrusion port 333 on the extrusion block body 331. The extrusion flow channel 332 is connected to the main flow channel 322, and the flow channel width of the extrusion flow channel 332 gradually increases, and the flow channel height gradually decreases. Those skilled in the art know that the cross-sectional width of the extrusion port 333 should match the width of the base paper 8, and the cross-sectional height should match the thickness of the composite functional layer 9'.

[0044] In this embodiment, three functional coating flow channels are included, namely the first to third functional melt flow channels 312, 313, and 314, so that the melt layering composite device 3 of this embodiment can prepare a composite coating material 9 including two functional fluid layers, and can also prepare a composite coating material 9 including three functional fluid layers.

[0045] The first to third feeding sections 3121, 3131, 3141 of the first to third functional melt channels 312, 313, 314 respectively form the first to third feeding ports on the feeding block body 31. The first to third feeding ports are respectively connected to the melt tanks, and the three melt tanks can form different functional granular materials into melts with fluidity and provide corresponding melts to the three feeding ports respectively. In order to avoid mutual interference, the first to third feeding sections 3121, 3131, 3141 are staggered, for example, the first feeding section 3121 is vertically arranged along the z-axis direction; the second feeding section 3131 is rotated and tilted with the first feeding section 3121 on the x-axis as the axis, preferably tilted to one side by 20°~30°, and spaced apart from the first feeding section 3121 along the x-axis direction; the third feeding section 3141 is symmetrically spaced apart from the second feeding section 3131 in the x-axis direction, and preferably tilted to the other side by 20°~30°. Correspondingly, the first to third flow stabilizing sections 3122, 3132, 3142 respectively connected to the first to third feeding sections 3121, 3131, 3141 are also spaced apart from each other. The first flat flow section 3123 extending from the first flow stabilizing section 3122 is located at the bottom layer in the z-axis direction, the second flat flow section 3133 extending from the second flow stabilizing section 3132 is located above the first flat flow section 3123 in the z-axis direction, and the third flat flow section 3143 extending from the third flow stabilizing section 3142 is located at the top layer in the z-axis direction. On the premise of not interfering with each other, the spacing between the first to third flat flow sections 3123, 3133, 3143 should be minimized.

[0046] The first flat flow section 3123 continues to extend in the opposite direction of the x-axis to form a first expansion section 3124, and the first expansion section 3124 continues to extend in the opposite direction of the x-axis to form a main flow channel 322. The second flat flow section 3133 continues to extend in the opposite direction of the x-axis to form a second expansion section 3134, and the second expansion section 3134 continues to extend to form a second converging bend 3135 that bends downward along the z-axis direction. The second converging bend 3135 first merges into the main flow channel 322, and as the second converging bend 3135 merges into the main flow channel 322, the flow channel height of the main flow channel 322 increases by 50% to 60%. The third horizontal flow section 3143 continues to extend in the opposite direction of the x-axis to form a third expansion section 3144, and the third expansion section 3144 continues to extend to form a third confluence bend 3145 that bends downward along the z-axis direction. The third confluence bend 3145 merges into the main channel 322 after the second confluence bend 3135, and with the confluence of the third confluence bend 3145, the flow channel height of the main channel 322 increases again by 50%~60%.

[0047] Preferably, the flow channel heights of the first to third flat flow sections 3123, 3133, 3143 gradually decrease, and the flow channel height at the end is 45% to 50% compared to the starting flow channel height. For example, the first flat flow section 3123 includes a front section with an equal flow channel height and a rear section with a gradually decreasing flow channel height, the second flat flow section 3133 also includes a front section with an equal flow channel height and a rear section with a gradually decreasing flow channel height, and the third flat flow section 3143 only includes a rear section with a gradually decreasing flow channel height.

[0048] Those skilled in the art know that, in order to facilitate mold opening, cleaning, maintenance, etc., the feed block 31 and the confluence block 32 are divided into a plurality of modules that can be screwed together for assembly. At the same time, in order to enable the fluid to maintain the temperature set in the process during the flow of the melt layered compounding device 3, at least an electric heating rod is provided in the feed block 31 and the confluence block 32 to provide temperature to the feed block body 311 and the confluence block body 321.

[0049] The coating device 4 includes a guide head 41 docked and assembled with the extrusion port 333 , and a steering feed roller 42 docked and matched with the guide head 41 .

[0050] Specifically, the guide head 41 includes a guide head body 411 screwed on the extrusion block 33, and a drainage channel is provided in the guide head body 411. The drainage channel includes a connecting section 412, an outflow section 413, and an arc transition section 414 connecting the connecting section 412 and the outflow section 413. The connecting section 412 is connected to the extrusion port 333 so that the extrusion channel 332 is connected. The connecting section 412 is arranged horizontally (in the x-axis direction), and the coating can flow in the connecting section 412 in the reverse direction along the x-axis. The outflow section 413 is tilted downward after turning through the arc transition section 414, and has an angle of 5° to 10° with the horizontal plane, and forms a flow outlet on the guide head body 411.

[0051] In order to make the steering feed roller 42 connect with the guide head 41 more smoothly and receive the composite coating material 9, in one aspect, preferably, the guide facade 4111 of the guide head body 411 with the outflow port is an inclined plane with an inclination angle of 15°~20°, and the roller surface of the steering feed roller 42 is linearly abutted with the guide facade 4111, and the abutment is located below the outflow port. At the same time, the steering device 2 supplies the base paper 8 to the bottom of the steering feed roller 42 and has a certain gap with the steering feed roller 42; when the base paper 8 passes under the steering feed roller 42, the base paper 8 is tilted downward by 3°~5°. In another aspect, the roller radius of the steering feed roller 42 is 10cm~15cm, and the roller speed of the steering feed roller 42 is 50rpm~60rpm.

[0052] By providing the deflection feed roller 42, the misalignment between the converging flow and the slight fluid stratification that may be formed due to gravity during the extrusion process can be corrected to a certain extent.

[0053] The compounding device 5 includes a pair of hot rollers, and the base paper 8 with the composite coating material 9 is passed between the pair of hot rollers, and the composite coating material 9 is solidified to form a composite functional layer 9' attached to the surface of the base paper 8, thereby obtaining a root barrier film 10, and the composite functional layer 9' has a certain adhesion. The punching device 6 is a hot punching machine in the prior art. The winding device 7 is a winding machine in the prior art.

[0054] The working method of a co-extrusion composite production line for preparing a special root barrier film for straw matrix disks in this embodiment is as follows:

[0055] Connect the first to third feeding ports on the feeding block 31 to the three melt tanks respectively;

[0056] The first melt flows into the first feed section 3121 through the first feed port, and passes through the first flow stabilization section 3122 along the flow channel until it flows into the main flow channel 322;

[0057] The second melt flows into the second material feeding section 3131 through the second coating port, and passes through the second flow stabilizing section 3132 in sequence along the flow channel until it flows into the second converging bend 3135, and is merged into the main flow channel 322 under the guidance of the second converging bend 3135, thereby forming a composite coating material in the main flow channel 322 with the lower layer being the first fluid layer and the upper layer being the second fluid layer;

[0058] The composite coating material is further flattened and reduced in thickness in the extrusion flow channel 332 to obtain the composite coating material 9, and in the process, a preliminary bonding strength is formed between the first fluid layer and the second fluid layer;

[0059] Subsequently, the composite coating material 9 is provided to the roller surface of the steering feed roller 42 by the guide head 41. As the steering feed roller 42 contacts the surface of the base paper 8, the composite coating material 9 is provided to the surface of the base paper 8. At this time, the surface of the base paper 8 is formed by the second fluid layering 92 and the first coating film 91 formed by the first fluid layering from bottom to top.

[0060] Then, the base paper 8 carrying the composite fluid layer 9 first passes through a pair of hot rollers of a composite device 5, and then passes through a punching device 6 to obtain a root barrier film 10;

[0061] Finally, the root barrier film 10 is rolled up.

[0062] Based on the above description, the art can derive a situation in which three melts are introduced.

[0063] The above description is intended to be illustrative and not limiting. Upon reading the above description, many embodiments and many applications beyond the examples provided will be apparent to those skilled in the art. Therefore, the scope of the present teachings should not be determined with reference to the above description, but should be determined with reference to the appended claims and the full scope of equivalents to which such claims are entitled. For the purpose of comprehensiveness, all articles and references, including disclosures of patent applications and publications, are incorporated herein by reference. The omission of any aspect of the subject matter disclosed herein in the preceding claims is not intended to be a waiver of the subject matter, nor should it be considered that the applicant has not considered the subject matter to be part of the disclosed application subject matter.

Claims

1. A co-extrusion composite production line for preparing a special root barrier film for straw matrix disc, characterized in that: It includes a main frame, and an unwinding device, a steering device, a melt layering and compounding device, a laminating device, a compounding device, a punching device and a winding device installed through the main frame; The melt layered compounding device comprises a feed block, a confluence block and an extrusion block; The feed block comprises a feed block body, a plurality of functional melt flow channels are arranged in the feed block body, the functional melt flow channels comprise a feed section, a steady flow section and a flat flow section which are connected in sequence, the feed sections of the plurality of functional melt flow channels respectively form feed ports on the feed block body, and the flat flow sections of the plurality of functional melt flow channels are stacked along the z-axis direction; The confluence block comprises a confluence block body, in which a main flow channel is arranged, the main flow channel is connected with the flat flow section located at the bottom layer, and the other flat flow sections are sequentially converged downward into the main flow channel through the confluence bends in order from bottom to top, and the flow channel height of the main flow channel increases after each confluence bend is connected with the confluence bend; The extrusion block includes an extrusion block body, in which an extrusion flow channel is arranged, and the end of the extrusion flow channel forms an extrusion port on the extrusion block body. The extrusion flow channel is connected to the main flow channel, and the flow channel width of the extrusion flow channel gradually increases and the flow channel height gradually decreases.

2. The co-extrusion composite production line for preparing a special root barrier film for straw matrix disk according to claim 1 is characterized in that: According to the flow direction, the flow stabilization section is vertically arranged along the z-axis direction, and the flow leveling section is horizontally arranged along the x-axis direction.

3. The co-extrusion composite production line for preparing a special root barrier film for straw matrix disk according to claim 2 is characterized in that: The steady flow section comprises a fan-shaped channel, the fan-shaped upper part of which is connected with the feed section, and the fan-shaped lower part of which is connected with the flat flow section in a bent manner.

4. The co-extrusion composite production line for preparing a special root barrier film for straw matrix disk according to claim 3 is characterized in that: Compared with the flow channel height of the fan-shaped upper part of the steady flow section, the flow channel height of the fan-shaped lower part is 45% to 50% of the initial flow channel height.

5. The co-extrusion composite production line for preparing a special root barrier film for straw matrix disk according to claim 1, characterized in that: The flat flow section is connected to the bend through the expansion section. Along the flow direction, the flow channel width of the expansion section gradually increases and the flow channel height gradually decreases.

6. The co-extrusion composite production line for preparing a special root barrier film for straw matrix disk according to claim 1, characterized in that: The coating device includes a guide head docked and assembled with the extrusion port, and a steering feed roller docked and matched with the guide head; the guide head includes a guide head body, a drainage channel is provided in the guide head body, the drainage channel includes a connecting section, an outflow section, and an arc transition section connecting the connecting section and the outflow section, the connecting section is connected to the extrusion channel and is horizontally arranged along the x-axis direction, the outflow section is inclined downward, and has an angle of 5°~10° with the horizontal plane, and a flow outlet is formed on the guide head body.

7. The co-extrusion composite production line for preparing a special root barrier film for straw matrix disk according to claim 6, characterized in that: The guiding outer facade of the guiding head body having the outflow port is an inclined plane with an inclination angle of 15° to 20°, and the roller surface of the steering feed roller is linearly abutted against the guiding outer facade, and the abutment point is located below the outflow port.

8. The co-extrusion composite production line for preparing a special root barrier film for straw matrix disk according to claim 6, characterized in that: The roller radius of the steering feed roller is 10cm~15cm.

9. The co-extrusion composite production line for preparing a special root barrier film for straw matrix disk according to claim 6, characterized in that: The steering device supplies the base paper to the bottom of the steering feed roller and has a certain gap with the steering feed roller; when the base paper passes under the steering feed roller, the base paper tilts downward by 3° to 5°.

10. The co-extrusion composite production line for preparing a special root barrier film for straw matrix disk according to claim 1, characterized in that: The punching device is a thermal puncher.

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