Multilayer slit type coating head

Abstract

The invention discloses a multi-layer slit type coating head, belongs to the field of coating heads, and solves the problems that the thicknesses of all parts of a coating formed at an outlet of a coating head are difficult to be consistent, and the orientation degree of a graphene film is low. According to the technical scheme, the multi-layer slit type coating head mainly comprises a shell, and a feeding channel and a flow channel are formed in the shell; a discharging port is formed in the front end of the shell, the feeding channel transversely penetrates through the shell, the flow channel comprises a first channel, a material storage channel and a second channel, the bottom end of the first channel is communicated with the feeding channel, the top end of the first channel is communicated with the top end of the material storage channel, and the material storage channel is communicated with the discharging port through the second channel. The top end of the material storage channel is higher than the discharging port in the height direction, and a plurality of narrow flow channels are formed in the second channel and distributed at intervals. The device is mainly used for enabling the density of the graphene oxide slurry to be more uniform after the graphene oxide slurry passes through the material storage channel and the second channel, so as to obtain the high-orientation graphene film.

Description

Technical Field

[0001] The present invention discloses a multi-layer slit coating head, belonging to the technical field of coating heads. Background Art

[0002] The graphite oxide film is obtained by forming a coating layer that meets the thickness requirements on a coating base belt after passing the graphite oxide slurry through a flat coating head; during the production process, the graphite oxide slurry is passed through the flat coating head and accumulates between the coating head and the coating base belt; when the coating base belt moves forward, the graphite oxide slurry is scraped flat to the required thickness by a comma knife to form a graphite oxide coating on the coating base belt, and the graphite oxide film is obtained after drying.

[0003] However, in the prior art, a feed channel and a flow channel are provided inside the coating head. The flow channel is directly connected to the feed channel and the outlet of the coating head. The feed channel forms inlets on both sides of the coating head. The graphite oxide slurry is filled into the feed channel from the two inlets at the same time. Since the graphite oxide slurry is a non-Newtonian fluid, the viscosity of the slurry is large and the self-leveling property is poor. Therefore, the closer to the inlet of the feed channel, the greater the pressure of the graphite oxide slurry, that is, the pressure of the graphite oxide slurry in the flow channel is uneven, and it is difficult to make the thickness of each part of the coating formed at the outlet of the coating head consistent, and the orientation degree of the graphene film is low, ultimately affecting the performance of the finished graphene film. Summary of the Invention

[0004] The purpose of the present invention is to solve the problem that it is difficult to make the thickness of each part of the coating formed at the outlet of the coating head consistent and the orientation degree of the graphene film is low. For this reason, a multi-layer slit coating head is provided. After the graphite oxide slurry passes through the storage channel and the second channel, the pressure of the graphite oxide slurry can be made more uniform, and the shear rate of the graphite oxide slurry is increased through the multi-layer slits, so that the graphene sheets in the slurry are arranged parallel to the flow direction and overlap at the outlet to form a coating layer with the required thickness, and a highly oriented graphene film is obtained after drying.

[0005] To solve the above technical problems, the present invention adopts the following technical solutions: A multi-layer slit coating head includes a housing. A feed channel and a flow channel are provided inside the housing. An outlet is provided at the front end of the housing. The feed channel horizontally penetrates the housing and forms inlets on both sides of the housing. The flow channel includes a first channel, a storage channel, and a second channel. The bottom end of the first channel is connected to the feed channel, the top end of the first channel is connected to the top end of the storage channel, the storage channel is connected to the outlet through the second channel, the top end of the storage channel is higher than the outlet in the height direction, and one end of the second channel close to the outlet forms a plurality of narrow flow channels, and the narrow flow channels are spaced apart along the height direction.

[0006] The beneficial effects of adopting the present invention are: In the present invention, the flow channel includes a first channel, a material storage channel, and a second channel. The bottom end of the first channel communicates with the feed channel, the top end of the first channel communicates with the top end of the material storage channel, and the material storage channel communicates with the discharge port through the second channel. That is, the first channel is entirely higher than the feed channel. Therefore, when the slurry enters the feed channel from the feed port, the slurry first needs to fill the feed channel before gradually spreading to the first channel. As the slurry continues to fill, under the action of gravity, the slurry will fully fill the feed channel, making the distribution of the slurry in the feed channel more uniform. The slurry also spreads from low to high in the first channel. Therefore, the pressure of the slurry in the first channel can be evenly distributed. After that, the flow of the slurry in the material storage channel and the second channel is not likely to affect the distribution of the slurry, and thus a coating with a uniform thickness distribution can be formed at the discharge port, enabling a finished graphene film with better thickness consistency to be obtained. Additionally, when the slurry passes through a narrow channel, the shear rate during flow can be significantly increased, resulting in shear thinning and a decrease in viscosity. Under the action of the shear force, the graphene wafers in the slurry can better form an arrangement parallel to the flow direction. The slurry overlaps in multiple layers at the discharge port to form a highly oriented and uniform-thickness graphene film.

[0007] Preferably, the housing includes a coating bottom plate and a coating top plate that are spliced together. The feed channel is provided in the coating bottom plate, the second channel and the discharge port are formed between the coating bottom plate and the coating top plate, and the top ends of the first channel and the material storage channel are formed in the coating top plate. With the foregoing technical solution, the housing is divided into a coating bottom plate and a coating top plate, making the structure of the coating head more modular, facilitating the disassembly and installation of the coating head. When it is necessary to clean, repair, or replace components of the coating head, the operation can be carried out more conveniently. At the same time, each component can be replaced or upgraded individually, which helps to reduce the maintenance cost and can also extend the service life of the coating head.

[0008] Preferably, a first partition plate and a second partition plate that are stacked in an alternating manner are clamped between the coating bottom plate and the coating top plate. A narrow channel is formed between two adjacent first partition plates in the second channel, and the second channel communicates with the discharge port through the narrow channel. With the foregoing technical solution, the alternating stacking of the first partition plate and the second partition plate can form a more stable support for each other, effectively reducing the possibility of deformation or fracture of the first partition plate and the second partition plate. Furthermore, it can ensure that the thickness of each narrow channel remains consistent, facilitating the formation of a coating with the same thickness and uniform distribution. Additionally, through the alternating stacking of the first partition plate and the second partition plate, a means for regulating the formation thickness of the coating is provided. The thickness and quantity of the coating can be precisely controlled by adjusting the thickness and quantity of the first partition plate and the second partition plate, making the coating process more controllable. Different application scenarios can be satisfied according to different coating requirements, enabling the coating head to have a wider range of applications.

[0009] Preferably, both the first partition plate and the second partition plate are provided with first notches for avoiding the first channel, and the first partition plate is provided with a second notch for avoiding the material storage channel.

[0010] Preferably, several support bodies are provided at one end of the second partition plate close to the discharge port, and the support bodies are spaced apart in the transverse direction of the housing. The support bodies pass through the material storage channel and extend into the second channel. With the foregoing technical solution, the support bodies can form a stable support for the first partition plate, thereby reducing the possibility that the first partition plate is deformed or collapsed, resulting in the deformation of the narrow channel, so that the thickness of the narrow channel can be kept consistent, so that the coating with a uniform thickness at each part is formed after the slurry passes through the narrow channel, which helps to improve the quality of the coating.

[0011] Preferably, the width of the support body gradually decreases as it approaches the discharge port, and the narrow channel is formed on the front side of the support body. With the foregoing technical solution, it is possible to avoid problems such as partial missing or uneven distribution of the coating caused by the support body, make the distribution of the slurry in the narrow channel more uniform, so as to facilitate the formation of a coating with a uniform thickness at each part, and thus a finished graphene film with better performance can be obtained.

[0012] Preferably, a covering body corresponding to the support body is provided in the second notch, and the covering body and the support body coincide with each other in the orthographic projection in the vertical direction. With the foregoing technical solution, the covering body can form a stable support for the support body and prevent the support body from being deformed or broken.

[0013] Preferably, connecting portions are provided on both sides of the first partition plate and the second partition plate. The front ends of the connecting portions extend into the second channel. There is a connecting plate between the connecting portions on both sides of the first partition plate, and a third notch is formed between the connecting portions on both sides of the second partition plate. The narrow channel is formed between two adjacent connecting plates.

[0014] Preferably, the bottom end of the material storage channel is lower than the discharge port in the height direction.

[0015] Other features and advantages of the present invention will be disclosed in detail in the following specific embodiments and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The following further describes the present invention with reference to the drawings: Figure 1 is a schematic structural diagram of a multi-layer slot coater of the present invention; Figure 2 is a cross-sectional view of a multi-layer slot coater of the present invention Figure 3 is a schematic structural diagram of a multi-layer slot coater of the present invention with the coating top plate removed; Figure 4Schematic structural diagram of a coating bottom plate in a multi-layer slit coating head of the present invention; Figure 5 Schematic structural diagram of a flow channel top plate in a multi-layer slit coating head of the present invention; Figure 6 Schematic structural diagram of a first partition plate and a second partition plate in a multi-layer slit coating head of the present invention; Figure 7 is Figure 6 partial enlarged view of part A in Figure 8 Schematic structural diagram of a first partition plate in a multi-layer slit coating head of the present invention; Figure 9 Schematic structural diagram of a second partition plate in a multi-layer slit coating head of the present invention.

[0017] Figure 10 SAXS characterization of a highly oriented graphene oxide film extruded based on the present invention.

[0018] Reference numerals: 11, coating top plate; 111, flow channel top plate; 112, pressing plate; 12, coating bottom plate; 121, flow channel bottom plate; 122, feeding bottom plate; 21, feeding channel; 211, feeding port; 22, first channel; 23, storage channel; 24, second channel; 25, discharging port; 31, first partition plate; 311, connecting plate; 312, covering body; 32, second partition plate; 321, supporting body; 322, third notch; 33, first notch; 34, second notch; 35, connecting portion; 36, narrow channel. Detailed implementation manners

[0019] The technical solutions of the embodiments of the present invention will be explained and described below with reference to the accompanying drawings of the embodiments of the present invention. However, the following embodiments are only the preferred embodiments of the present invention and not all of them. Based on the embodiments in the implementation manners, other embodiments obtained by those skilled in the art without creative efforts fall within the protection scope of the present invention.

[0020] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "clockwise", "counterclockwise", etc. is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present invention.

[0021] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present invention, "a plurality of" means two or more unless otherwise clearly defined.

[0022] In the present invention, unless otherwise clearly specified and defined, terms such as "mounted", "connected", "coupled", "fixed", etc. shall be construed in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0023] As Figures 1 to 9 shown, this embodiment demonstrates a multi-layer slit coating head, including a housing. An inlet channel 21 and a flow channel are provided inside the housing. An outlet 25 is provided at the front end of the housing. The inlet channel 21 horizontally penetrates the housing and forms inlet ports 211 on both sides of the housing. The flow channel includes a first channel 22, a storage channel 23, and a second channel 24. The bottom end of the first channel 22 is in communication with the inlet channel 21, the top end of the first channel 22 is in communication with the top end of the storage channel 23, the storage channel 23 is in communication with the outlet 25 through the second channel 24, the top end of the storage channel 23 is higher than the outlet 25 in the height direction, the second channel 24 is horizontally arranged, and one end of the second channel 24 close to the outlet 25 forms a plurality of narrow flow channels 36, and the narrow flow channels 36 are spaced apart in the height direction.

[0024] In this embodiment, the flow channel includes a first channel 22, a material storage channel 23, and a second channel 24. The bottom end of the first channel 22 is communicated with the feed channel 21, the top end of the first channel 22 is communicated with the top end of the material storage channel 23, and the material storage channel 23 is communicated with the discharge port 25 through the second channel 24. That is, the first channel 22 is entirely higher than the feed channel 21. Therefore, when the slurry enters the feed channel 21 from the feed port 211, the slurry first needs to fill the feed channel 21 before gradually spreading to the first channel 22. With the continuous filling of the slurry, under the action of gravity, the slurry will fully fill the feed channel 21, making the distribution of the slurry in the feed channel 21 more uniform. The slurry also spreads from low to high in the first channel 22. Therefore, the pressure of the slurry in the first channel 22 can be evenly distributed. After that, the flow of the slurry in the material storage channel 23 and the second channel 24 is not likely to affect the distribution of the slurry, and then a coating with a uniform thickness distribution can be formed at the discharge port 25, so that a finished graphene film with better thickness consistency can be obtained. In addition, when the slurry passes through the narrow channel 36, the shear rate during flow can be significantly increased, resulting in shear thinning and a decrease in viscosity. Under the action of the shear force, the graphene wafers in the slurry can better form an arrangement parallel to the flow direction. The slurry overlaps in multiple layers at the discharge port 25 to form a graphene film with high orientation and uniform thickness.

[0025] Such as Figure 1 And Figure 2As shown, in this embodiment, the housing includes a coating bottom plate 12 and a coating top plate 11 that are spliced together. The coating top plate 11 is covered on the upper side of the coating bottom plate 12. The coating bottom plate 12 includes a feeding bottom plate 122 and a flow channel bottom plate 121, and the coating top plate 11 includes a feeding top plate and a flow channel top plate 111. The feeding channel 21 horizontally penetrates the feeding bottom plate 122 and forms feeding ports 211 on both sides of the feeding bottom plate 122. The flow channel bottom plate 121 is covered on the upper side of the feeding bottom plate 122. A part of the first channel 22 is inside the flow channel bottom plate 121, and the bottom end of the first channel 22 communicates with the top end of the feeding channel 21. The flow channel top plate 111 is covered on the flow channel bottom plate 121. The flow channel top plate 111 has another part of the first channel 22 and a storage channel 23. The first channel 22 and the storage channel 23 communicate at the top of the flow channel top plate 111, that is, the first channel 22 and the storage channel 23 form an inverted U shape inside the flow channel top plate 111. After the flow channel top plate 111 and the flow channel bottom plate 121 are installed, a second channel 24 is formed on the right side of the storage channel 23 between the flow channel top plate 111 and the flow channel bottom plate 121. The storage channel 23 communicates with the discharge port 25 through the second channel 24. The pressing plate 112 is installed on the upper side of the flow channel top plate 111 and seals the first channel 22 and the storage channel 23. Dividing the housing into the coating bottom plate 12 and the coating top plate 11 makes the structure of the coating head more modular, facilitating the disassembly and installation of the coating head. When it is necessary to clean, repair or replace components of the coating head, the operation can be carried out more conveniently. At the same time, each component can be replaced or upgraded individually, which helps to reduce the maintenance cost and can also extend the service life of the coating head.

[0026] As Figure 4 and Figure 5 shown, in this embodiment, both the first channel 22 and the storage channel 23 are vertically arranged, and the second channel 24 is horizontally arranged. Such an arrangement can make the production of the coating bottom plate 12 and the coating top plate 11 simpler, ensure that after the coating bottom plate 12 and the coating top plate 11 are spliced, the feeding channel 21 and the flow channel can be accurately connected and docked. At the same time, it can also simplify the sealing difficulty of the coating bottom plate 12 and the coating top plate 11, reduce the possibility of slurry leakage in the coating head, keep the slurry at a higher pressure in the coating head, and further make the distribution of the slurry in the feeding channel 21 more uniform, so as to facilitate the formation of a coating with a uniform thickness distribution at the discharge port 25, thereby obtaining a finished graphene film with better performance.

[0027] In addition, in this embodiment, a groove is provided on the upper surface of the runner bottom plate 121. The groove is aligned with the discharge channel. After the runner bottom plate 121 and the runner top plate 111 are spliced, the groove forms the bottom end of the discharge channel, that is, the bottom end of the storage channel 23 is lower than the discharge port 25 in the height direction. In addition, the second channel 24 is formed between the upper surface of the runner bottom plate 121 and the lower surface of the runner top plate 111. Therefore, the bottom end of the storage channel 23 is also lower than the second channel 24. When the slurry flows from the first channel 22 into the storage channel 23, the slurry will fall onto the upper surface of the runner bottom plate 121 under the action of gravity. The setting of the groove can make part of the slurry stay in the storage channel 23 and reduce the direct entry of the slurry into the second channel 24. Therefore, the flow rate of the slurry entering the storage channel 23 from the first channel 22 will be greater than the flow rate of the slurry entering the second channel 24 from the storage channel 23, that is, the slurry in the storage channel 23 will continuously increase until the storage channel 23 is filled with the slurry, so that the slurry in the storage channel 23 can be extruded into the second channel 24 under the action of pressure. The slurry enters the second channel 24 through extrusion, which can make the slurry in the second channel 24 more substantial and avoid the problems of slurry vacancy or uneven distribution.

[0028] As Figure 6 and Figure 7 shown, in this embodiment, a first partition 31 and a second partition 32 are interlaced and stacked between the coating bottom plate 12 and the coating top plate 11. The first partition 31 and the second partition 32 are both provided with a first notch 33 for avoiding the first channel 22. The first partition 31 is provided with a second notch 34 for avoiding the storage channel 23. Connecting portions 35 are provided on both sides of the first partition 31 and the second partition 32. The front ends of the connecting portions 35 extend into the second channel 24. A connecting plate 311 is provided between the connecting portions 35 on both sides of the first partition 31. A third notch 322 is formed between the connecting portions 35 on both sides of the second partition 32. A narrow channel 36 is formed between two adjacent first partitions 31 in the second channel 24. The second channel 24 communicates with the discharge port 25 through the narrow channel 36. The interlaced stacking of the first partition 31 and the second partition 32 can form a more stable support for each other, effectively reducing the possibility of deformation or fracture of the first partition 31 and the second partition 32, and then ensuring that the thickness of each narrow channel 36 can be kept consistent, so as to obtain a coating with the same thickness and uniform distribution. In addition, through the interlaced stacking of the first partition 31 and the second partition 32, a means for regulating the thickness of the coating is provided. The thickness and quantity of the coating can be accurately controlled by adjusting the thickness and quantity of the first partition 31 and the second partition 32, making the coating process more controllable, meeting different application scenarios according to different coating requirements, and enabling the coating head to have a wider range of applications. Generally speaking, the thickness of the first partition 31 and the second partition 32 can be set between 0.1 and 1 mm.

[0029] As shown Figure 8 and Figure 9 In this embodiment, as shown, a plurality of support bodies 321 are provided at one end of the second partition plate 32 close to the discharge port 25. The support bodies 321 are spaced apart in the lateral direction of the housing. The support bodies 321 pass through the storage channel 23 and extend into the second channel 24. The width of the support bodies 321 gradually decreases as they approach the discharge port 25. A narrow channel 36 is formed on the front side of the support bodies 321. A covering body 312 corresponding to the support bodies 321 is provided in the second notch 34. The covering body 312 and the support bodies 321 overlap in the vertical direction in the orthographic projection. The support bodies 321 can stably support the first partition plate 31, thereby reducing the possibility that the narrow channel 36 is deformed due to the deformation or collapse of the first partition plate 31, so that the thickness of the narrow channel 36 can be kept consistent, so that the slurry forms a coating with a consistent thickness at each part after passing through the narrow channel 36, which helps to improve the quality of the coating. In addition, the width of the support bodies 321 gradually decreases as they approach the discharge port 25, which can avoid the problem of partial absence or uneven distribution of the coating caused by the support bodies 321, make the distribution of the slurry in the narrow channel 36 more uniform, so as to form a coating with a consistent thickness at each part, and thus a graphene film with better performance can be obtained. Secondly, the covering body 312 can stably support the support bodies 321 and prevent the support bodies 321 from deforming or breaking.

[0030] During use, an aqueous solution of graphene oxide (graphene oxide slurry) with a concentration of 1 mg / ml is injected into the multi-layer slit coater of the present invention through the feeding ports 211 on both sides. The graphene oxide slurry passes through the first channel 22, the storage channel 23 and the second channel 24, and finally undergoes horizontal shear orientation through the narrow channel 36 to form a multi-layer graphene oxide gel film. And at the moment of extrusion, the upper and lower graphene oxide films are fused with each other at the interface, so as to obtain a highly oriented graphene oxide thick film, as shown Figure 10 shown. According to Figure 10 we can determine that the graphene oxide film is almost entirely horizontally oriented.

[0031] The above is only the specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that the present invention includes but is not limited to the content described in the drawings and the above specific implementation manner. Any modification that does not deviate from the functional and structural principles of the present invention will be included in the scope of the claims.

Claims

1. A multi-layer slit coating head, characterized in that: It includes a housing, in which a feeding channel and a flow channel are provided. An outlet is provided at the front end of the housing. The feeding channel transversely penetrates the housing and forms feeding ports on both sides of the housing. The flow channel includes a first channel, a storage channel, and a second channel. The bottom end of the first channel is communicated with the feeding channel, the top end of the first channel is communicated with the top end of the storage channel, the storage channel is communicated with the outlet through the second channel. The top end of the storage channel is higher than the outlet in the height direction. Several narrow channels are formed at one end of the second channel close to the outlet, and the narrow channels are spaced apart in the height direction.

2. The multi-layer slot coater head according to claim 1, wherein: The housing includes a coating bottom plate and a coating top plate that are spliced with each other. The feeding channel is arranged on the coating bottom plate, the second channel and the outlet are formed between the coating bottom plate and the coating top plate, and the top ends of the first channel and the storage channel are formed in the coating top plate.

3. The multi-layer slot die coater according to claim 2, characterized in that: A first partition plate and a second partition plate that are stacked alternately are clamped between the coating bottom plate and the coating top plate. A narrow channel is formed between two adjacent first partition plates in the second channel, and the second channel is communicated with the outlet through the narrow channel.

4. The multi-layer slot coater according to claim 3, characterized in that: Both the first partition plate and the second partition plate are provided with first notches for avoiding the first channel, and the first partition plate is provided with a second notch for avoiding the storage channel.

5. The multi-layer slot coating head according to claim 4, wherein: Several support bodies are provided at one end of the second partition plate close to the outlet, and the support bodies are spaced apart in the transverse direction of the housing. The support bodies pass through the storage channel and extend into the second channel.

6. The multi-layer slot coater head according to claim 5, wherein: The width of the support body gradually decreases as it approaches the outlet, and the narrow channel is formed on the front side of the support body.

7. The multi-layer slot coating head according to claim 5, wherein: A covering body corresponding to the support body is arranged in the second notch, and the orthographic projection of the covering body and the support body in the vertical direction coincides with each other.

8. The multi-layer slot coater according to claim 3, characterized in that: Connection parts are provided on both sides of the first partition plate and the second partition plate. The front ends of the connection parts extend into the second channel. A connecting plate is provided between the connection parts on both sides of the first partition plate. A third notch is formed between the connection parts on both sides of the second partition plate. The narrow channel is formed between two adjacent connecting plates.

9. The multi-layer slot coater head according to claim 1, characterized in that: The bottom end of the storage channel is lower than the outlet in the height direction.

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