Graphene Oxide Membrane Production System

Abstract

The present invention provides a production system for graphene oxide membranes, which includes a feeding unit, an extrusion coating unit, a drying unit, and a winding unit. The coating substrate is output by the feeding unit and successively passes through the extrusion coating unit and the drying unit and is wound on the winding unit. The extrusion coating unit includes a coating roller and a material tank. A coating substrate is tensionally connected to the coating roller. A doctor blade is disposed adjacent to the coating roller. The doctor blade is on the side of the coating substrate away from the coating roller, and a coating gap is formed between the doctor blade and the coating side of the coating substrate. The material tank has a feed port and a discharge port. The discharge port is correspondingly disposed with the coating side of the coating substrate. An extrusion die head is provided at the feed port, and the extrusion die head can extrude the graphene oxide slurry into the material tank. In the present invention, the graphene oxide slurry in the material tank obtains a slurry with a flat liquid surface, and the slurry in the material tank can be coated under the pressure of its own weight to form a graphene oxide wet film with a uniform and large thickness.

Description

Technical Field

[0001] The invention belongs to the technical field of graphene film production systems, and in particular relates to a graphene oxide film production system. Background Art

[0002] In the prior art, the following two methods are generally used to coat the slurry on the substrate: one is extrusion coating, which is to spray the slurry onto a vertically stretched substrate, and the extrusion lip is perpendicular to the coated substrate and the distance is very close. The distance is related to the wet film thickness and coating speed, about tens to hundreds of μm. In this way, if the slurry is sprayed too thick, the slurry on the substrate will flow down, resulting in an uneven film surface, and a thick wet film cannot be obtained. Therefore, the thickness of the film coated in this way is generally The thickness of the wet film does not exceed 1mm, but the coating of graphene oxide slurry needs to obtain a wet film thickness of 1 to 4mm; the other is transfer coating, which is to scrape a certain thickness of the slurry onto the coating roller through the gap between the coating roller and the scraper. The coating roller rotates continuously, and then the back roller with the coating substrate leans against the coating roller to transfer the film on the coating roller to the coating substrate. Because the coating roller and the back roller are set parallel to the horizontal plane, when rotating, if the wet film is too thick, the shape of the film will change, resulting in uneven coating thickness. That is, the extrusion coating and transfer coating methods in the prior art cannot form a graphene oxide film with a larger thickness (1-4mm) and uniform thickness.

[0003] In addition, the formation of a thick graphene oxide film will have the problem of inconsistent drying degree during the drying process, which causes the edge of the graphene film to be drier than the central part, which will cause the two sides of the graphene film to curl and the graphene film to have poor flatness; at the same time, excessive drying will cause the subsequent graphene oxide film to be easily damaged when it is peeled off from the substrate. Summary of the invention

[0004] In order to solve at least one of the above problems, the present invention provides a graphene oxide film production system, including a loading unit, an extrusion coating unit, a drying unit, and a receiving unit. The coated substrate is output by the loading unit and passes through the extrusion coating unit and the drying unit in sequence and is wound up in the receiving unit. The extrusion coating unit includes a coating roller and a material trough. The coating roller is tensionedly connected to the coating substrate, and a scraper is arranged adjacent to the coating roller. The coating roller is located on the side of the coated substrate away from the coating roller, and a coating gap is formed between the scraper and the coating side of the coated substrate. The material trough has a feed port and a discharge port, and the discharge port is arranged corresponding to the coating side of the coated substrate. An extrusion die is arranged at the feed port, and the extrusion die can extrude the graphene oxide slurry into the material trough.

[0005] Preferably, the drying unit includes a first drying box, which is located downstream of the traveling direction of the coated substrate. A first roller is provided at the inlet of the first drying box. The coated substrate is tensioned between the coating roller and the first roller, and an angle a is formed between the roller exit direction of the coated substrate and the horizontal plane, 8°≤a≤20°.

[0006] Preferably, the line between the axis of the scraper and the axis of the coating roller intersects with the roller wall of the coating roller at point B, the point of separation of the coating substrate and the coating roller is point C, point B is located on the side of point C close to the material trough, and the arc length between point B and point C is 5mm to 10mm.

[0007] Preferably, the extrusion coating unit further comprises a position adjustment component for adjusting the relative position of the scraper with respect to the coating roller, thereby adjusting the coating gap.

[0008] Preferably, the coated substrate is a breathable substrate.

[0009] Preferably, a plurality of drying boxes are sequentially and closely arranged in the drying unit along the traveling direction of the coated substrate, and the hot air flow speed and the drying temperature in each drying box can be independently adjusted.

[0010] Preferably, the speed of the hot air flow becomes higher and higher along the traveling direction of the coated substrate; and / or, a plurality of the drying boxes are assembled to form an arched drying tunnel structure; and / or, the traveling speed of the coated substrate is negatively correlated with the thickness of the graphene oxide film.

[0011] Preferably, the hot air flow speed is divided into low wind speed vl and high wind speed vh, wherein 3m / s≤vl≤10m / s, 20m / s≤vh≤30m / s; and / or, the drying temperature in the drying box is T, 50℃≤T≤80℃; and / or, the traveling speed of the coated substrate is vd, 0.5m / min≤vd≤2m / min.

[0012] Preferably, a wetting unit and a film stripping unit are further provided at the outlet of the drying unit. The wetting unit can rewet the dried graphene oxide film by means of water mist or steam. The film stripping unit is located between the wetting unit and the receiving unit, and can strip the graphene oxide film from the coated substrate.

[0013] Preferably, the rehumidification unit comprises a rehumidification box, the coating substrate divides the interior of the rehumidification box into an upper chamber and a lower chamber, the upper chamber is provided with a steam spraying device, and / or the lower chamber is provided with a water mist spraying device.

[0014] The present invention provides a graphene oxide film production system, wherein an extrusion coating unit utilizes the extrusion of the extrusion die head to extrude the graphene oxide slurry into the material tank, so that the slurry with a smooth liquid surface can be obtained in the material tank. The slurry in the material tank passes through the coating gap between the scraper and the coating side of the coating substrate under the pressure of its own weight, and flows and is coated on the coating side of the coating substrate, thereby forming a graphene oxide wet film with uniform thickness and large size. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 Schematic diagram of the structure of a graphene oxide film production system according to an embodiment of the present invention;

[0016] Figure 2 for Figure 1 A partial enlarged view of the middle A;

[0017] Figure 3 for Figure 1 A partial enlarged view of point B in the middle;

[0018] Figure 4 for Figure 1 A schematic diagram of the local structure of the extrusion coating unit;

[0019] Figure 5 for Figure 4 A partial enlarged view of point C in the middle;

[0020] Figure 6 It is a structural schematic diagram of the position adjustment component of the extrusion coating unit;

[0021] Figure 7 for Figure 1 A schematic structural diagram of an embodiment of a wet recovery unit in the embodiment (fastened state)

[0022] Figure 8 for Figure 7 Schematic diagram of the structure when the wetting unit is in the open state.

[0023] The reference numerals are:

[0024] 1. Coating roller; 2. Scraper; 3. Material trough; 4. Extrusion die; 5. First drying box; 51. First roller; 61. Mounting plate; 62. Swing arm; 63. Motor; 64. Lifting cylinder; 65. Limiter; 7. Film thickness detection component; 100. Feeding unit; 101. Coating substrate; 102. Double-station unwinding mechanism; 103. Material storage mechanism; 104. Material receiving mechanism; 105. Double-sided cleaning mechanism; 106. Unwinding traction mechanism; 10 7. Graphene oxide film; 200. Extrusion coating unit; 300. Drying unit; 400. Material collection unit; 401. First double-station winding mechanism; 402. Second double-station winding mechanism; 403. Cleaning mechanism; 404. Winding and traction mechanism; 500. Wetting unit; 501. Wetting box; 502. Upper chamber; 503. Lower chamber; 504. Steam spray device; 505. Water mist spray device; 600. Film stripping unit; 700. Control cabinet. DETAILED DESCRIPTION

[0025] See also Figures 1 to 8As shown, according to an embodiment of the present invention, a graphene oxide film production system is provided, comprising a feeding unit 100, an extrusion coating unit 200, a drying unit 300, and a receiving unit 400. The coated substrate 101 is output by the feeding unit 100 and sequentially passes through the extrusion coating unit 200 and the drying unit 300 and is wound in the receiving unit 400. The extrusion coating unit 200 comprises a coating roller 1 and a material trough 3. The coating roller 1 is tensionedly connected with the coating roller 1. A cloth substrate 101 is provided with a scraper 2 adjacent to the coating roller 1, the coating roller 1 is located on the side of the coating substrate 101 away from the coating roller 1, and a coating gap is formed between the scraper 2 and the coating side of the coating substrate 101, the material trough 3 has a feed port and a discharge port, the discharge port is arranged corresponding to the coating side of the coating substrate 101, and an extrusion die 4 is provided at the feed port, and the extrusion die 4 can extrude the graphene oxide slurry into the material trough 3. In this technical solution, the extrusion coating unit 200 utilizes the extrusion of the extrusion die 4 to extrude the graphene oxide slurry into the material tank 3, and a slurry with a smooth liquid surface can be obtained in the material tank 3. The slurry in the material tank 3 passes through the coating side of the coating substrate 101 (which can also be understood as the coating gap between the scraper 2 and the coating roller 1) under the pressure of its own weight, and flows and coats on the coating side of the coating substrate 101, thereby forming a graphene oxide wet film with uniform thickness. It can be understood that the extrusion die 4 utilizes a relatively large pressure to extrude the slurry from its internal cavity to its discharge port, and because its internal pressure is consistent, it ensures that the slurry outflow at each discharge port is equal. Therefore, a flat slurry liquid surface can be formed in the material tank 3, and the flat liquid surface of the slurry can make the coating pressure brought by the slurry's own weight consistent, thereby ensuring the uniform thickness of the film layer. It can be further understood that when the slurry liquid level in the material tank 3 is uneven, the pressure transmitted from the slurry in the material tank 3 to the coating point will be inconsistent, resulting in inconsistent and large coating thickness (experiments have shown that the extrusion coating unit 200 of the present application can be coated to form a wet film with a thickness of 1mm to 4mm), causing unevenness. Due to the high viscosity of the graphene oxide slurry, the conventional feeding method cannot obtain a flat liquid surface in the material tank 3, and the extrusion die head 4 in the present application can overcome this defect in the prior art.

[0026] In some embodiments, in order to obtain a wet film thickness of 1 to 4 mm, the viscosity of the graphene oxide slurry is controlled to be above 10,000 mPa.s and below 46,000 mPa.s. On the one hand, it can effectively avoid excessive flow of the wet film slurry, resulting in uneven film thickness, and on the other hand, it can also avoid the slurry viscosity being too high, resulting in internal bubbles that are difficult to remove. The graphene oxide slurry has a low solid content, only 2% to 8% of graphene oxide, and the rest is solvent (the main solvent is deionized water).

[0027] The drying unit 300 includes a first drying box 5, which is located downstream of the travel direction of the coated substrate 101 and is used to dry the formed graphene oxide wet film. The inlet of the first drying box 5 has a first roller 51. The coated substrate 101 is tensioned between the coating roller 1 and the first roller 51, and an angle a is formed between the roller exit direction of the coated substrate 101 and the horizontal plane, 8°≤a≤20°. Specifically, if a>20°, the wet film has a certain fluidity, which will form a wet film flow, thereby causing an uneven film layer. When a<8°, the wet film has no leveling process, which will result in fine textures on the film surface and the film layer will not be uniform enough.

[0028] Preferably, the line between the axis of the scraper 2 and the axis of the coating roller 1 intersects with the roller wall of the coating roller 1 at point B, the disengagement tangent point between the coating substrate 101 and the coating roller 1 is point C, point B is located on the side of point C close to the material tank 3, and the arc length between point B and point C is 5mm to 10mm. If it is less than 5mm, external vibration and other interference will affect the slurry coating and cause horizontal stripes. If it is greater than 10mm, the slurry in the material tank 3 is not easy to reach the scraper mouth of the scraper 2, and a thick wet film cannot be formed.

[0029] Furthermore, the graphene oxide film coating system further includes a position adjustment component for adjusting the relative position of the scraper 2 relative to the coating roller 1, thereby adjusting the coating gap. That is, the relative position between the scraper 2 and the coating roller 1 can be changed by the operation of the position adjustment component, thereby adjusting the thickness of the wet film, and thus enabling the coating system to meet the manufacturing requirements of graphene oxide films of different thicknesses.

[0030] As a specific embodiment of the position adjustment component, the position adjustment component includes a mounting plate 61, a swing arm 62 is pivotally connected to the mounting plate 61, the scraper 2 can be driven and rotatably connected to the swing arm 62, a motor 63 is provided at one end of the swing arm 62, and a lifting cylinder 64 is connected to the other end of the swing arm 62, the lifting cylinder 64 and the motor 63 are used to drive the position change of the scraper 2, more specifically, the lifting cylinder 64 is used to drive the scraper 2 to be lifted and lowered, and the motor 63 is used to accurately adjust the distance between the scraper 2 and the coating roller 1.

[0031] Preferably, a limiter 65 is further provided on the mounting plate 61 , and the limiter 65 is located on a side of the swing arm 62 away from the coating roller 1 , so as to limit the lifting and lowering displacement range of the swing arm 62 .

[0032] In some embodiments, a film thickness detection component 7 is provided at the coating substrate 101 between the coating roller 1 and the first passing roller 51. The film thickness detection component 7 can, for example, adopt an X-ray testing system which can move laterally so as to detect the thickness of the entire coating surface, and can control the operation of the motor 63 according to the detected real-time thickness, thereby adjusting the relative position of the scraper 2 and the coating roller 1 in real time, so as to further ensure the uniformity of the coating film thickness.

[0033] Preferably, the coating roller 1 is pivotally connected to the mounting plate 61; and / or the material trough 3 is connected to the mounting plate 61; and / or the extrusion die head 4 is connected to the mounting plate 61, that is, the coating roller 1, the material trough 3, the scraper 2 and the extrusion die head 4 are all mounted on the mounting plate 61, so that the relative position relationship between these components is more stable, and the structure is simpler and more compact.

[0034] In the prior art, after the graphene oxide slurry is coated into a wet film, it enters the subsequent drying unit 300 for drying. In this drying process, the surface of the wet film will be dried first, and the dried film surface will prevent the internal moisture from being discharged, thereby making the wet film difficult to dry and taking longer to dry. In order to improve the drying efficiency of the wet film, preferably, the coating substrate 101 adopts a breathable substrate. The breathable substrate can be, for example, one of PP monofilament textile fabric, PE monofilament textile fabric, and stainless steel mesh belt, so that the graphene oxide wet film can be dried on both sides at the same time, greatly improving the drying efficiency.

[0035] In some embodiments, in the drying unit 300, a plurality of drying boxes (including the first drying box 5 mentioned above) are arranged in sequence and closely together along the traveling direction of the coated substrate 101. The specific length of the drying boxes and the number of the drying boxes can be adjusted according to actual conditions. The hot air flow speed and the drying temperature in each drying box can be adjusted independently, so that they can be adjusted at any time according to the degree of dryness of the graphene oxide wet film. Furthermore, the wind speed of the hot air flow is getting higher and higher along the traveling direction of the coated substrate 101, that is, the drying wind speed of the graphene oxide wet film entering the drying unit 300 is relatively the lowest, and the drying wind speed of the graphene oxide film that is about to be output from the drying unit 300 is relatively the highest. This setting can ensure that the graphene oxide wet film is not subjected to the air flow disturbance of excessive wind speed when the fluidity is large, thereby ensuring the appearance quality of the final graphene oxide film 107. Specifically, the wind speed of the hot air flow is divided into a low wind speed vl and a high wind speed vh, wherein 3m / s≤vl≤10m / s, 20m / s≤vh≤30m / s, which can ensure the appearance quality of the graphene oxide film 107 while ensuring better drying efficiency. The length of the drying unit 300 should be designed to be relatively long to ensure that the graphene oxide wet film can be dried slowly. In some specific embodiments, the length of the drying unit 300 (that is, the total drying channel length of multiple drying boxes) is designed to be more than 64m.

[0036] After research, the inventors found that the traveling speed of the coated substrate 101 is negatively correlated with the thickness of the graphene oxide film 107, that is, the thicker the graphene oxide film 107, the lower the traveling speed of the coated substrate 101 should be to ensure thorough drying. Specifically, when the inventors used a slurry solid content of 5%, the gram weight of the graphene oxide film obtained with different coating wet film thicknesses and the corresponding coating drying speed (that is, the speed at which the coating system runs) are specifically shown in the table below.

[0037] Coated wet film thickness / μm <![CDATA[干燥后氧化石墨烯膜的克重 / g / m 2 ]]> Coating system running speed / m / min 760 38 4.62 1520 76 1.75 1860 93 1.34 2480 124 0.97 2740 137 0.82 3040 152 0.75 3720 186 0.5

[0038] In terms of temperature control, a lower drying temperature can obtain a graphene oxide film with fewer directional assembly defects, but due to its high cost, it lacks competitiveness, and a higher temperature causes the decomposition of oxygen-containing functional groups inside the graphene oxide film, and the graphene oxide film is prone to bulging and other poor appearances. Therefore, the inventor designs the drying temperature in the drying box to be T, 50°C≤T≤80°C; and / or, the travel speed of the coated substrate 101 is vd, 0.5m / min≤vd≤2m / min. The use of a travel speed within this range can take into account the drying efficiency while ensuring that the subsequent film stripping process is too fast to cause damage to the graphene oxide film.

[0039] As can be seen from the foregoing, during the drying process of the graphene oxide wet film in the drying unit 300, its upper surface will be dried first. At this time, the moisture in the wet film will be forced to precipitate from its two sides (that is, the two sides of its thickness), so that the wet film is dried first on both sides of the overall width and then in the middle, resulting in uneven drying, which in turn causes the two sides of the film (the left and right sides of the traveling direction) to curl upward. In order to weaken the curling and warping caused by such uneven drying, preferably, a plurality of the drying boxes are assembled to form an arched drying tunnel structure. Specifically, it can be understood that the rollers arranged therein have a height difference in the height direction, and the arched drying tunnel has a certain curvature, which reduces the horizontal distance of the film. The film between the two rollers and the film between the adjacent rollers are not parallel, and the two sides are tightened, thereby reducing curling.

[0040] Furthermore, a wetting unit 500 and a film stripping unit 600 are provided at the outlet of the drying unit 300. The wetting unit 500 can wet the dried graphene oxide film by means of water mist or steam, so that the over-dried part by the drying unit 300 can be moistened and softened, so that the subsequent peeling of the graphene oxide film 107 from the coated substrate 101 can be smoother, and the integrity of the graphene oxide film 107 after peeling can be ensured. The film stripping unit 600 is located between the wetting unit 500 and the receiving unit 400, and can peel the graphene oxide film from the coated substrate 101. It can be understood that the film stripping unit 600 contains a corresponding stripping knife.

[0041] As a specific implementation of the wet recovery unit 500, Figure 7 and 8As shown, the rewetting unit 500 includes a rewetting box 501, and the coated substrate 101 divides the interior of the rewetting box 501 into an upper chamber 502 and a lower chamber 503. A steam spray device 504 is provided in the upper chamber 502, and / or a water mist spray device 505 is provided in the lower chamber 503, so that the upper and lower surfaces of the graphene oxide film 107 can be rewetted at the same time, so that the film has as uniform flexibility as possible. It can be understood that the steam spray device 504 and the water mist spray device 505 are both connected to the corresponding external steam or atomization components in a controllable through connection, which will not be described here. It should be emphasized that the steam spray device 504 is provided in the upper chamber 502 of the present application to prevent the water mist from gathering and retaining the upper surface of the graphene oxide film 107 as much as possible, which has an adverse effect on its appearance. Furthermore, a corresponding heating component (such as a heating film) may be provided in the top wall of the box body of the wet box 501 to heat it and prevent the condensation of steam thereon to form water droplets. The wet box 501 may also be designed to have a structure having a box body (not labeled in the figure) and a cover body (not labeled in the figure), wherein the cover body is hinged to the box body and can be opened when needed.

[0042] In some embodiments, the loading unit 100 includes a double-station unwinding mechanism 102 and a material storage mechanism 103. The double-station unwinding mechanism 102 can replace the coated substrate 101 without stopping the machine, thereby improving the coating efficiency. A material connection mechanism 104 (specifically, a sewing machine can be used) is also provided between the double-station unwinding mechanism 102 and the material storage mechanism 103. The material connection mechanism 104 can sew the two ends of the coated substrate 101. Generally speaking, the coated substrate 101 is mostly a resin cloth of 0.35mm to 0.5mm. The commonly used tape bonding is not strong and is easy to break in the drying oven, so sewing is used. Furthermore, a double-sided cleaning mechanism 105 is provided between the material storage mechanism 103 and the extrusion coating unit 200. The material storage mechanism 103 can be provided with multiple groups before the coated substrate 101 enters the extrusion coating unit 200. When the coated substrate is replaced, the material in the material storage mechanism ensures continuous coating. Generally, the material storage length is 5m to 10m. The double-sided cleaning mechanism 105 is specifically formed by two oppositely arranged tape rollers. When the coated substrate 101 passes between the two tape rollers, the dust on it will be removed.

[0043] In some embodiments, the receiving unit 400 includes a first double-station winding mechanism 401 and a second double-station winding mechanism 402, wherein the first double-station winding mechanism 401 is used to wind up the graphene oxide film, and the second double-station winding mechanism 402 is used to wind up the coated substrate 101. The receiving unit 400 also includes a cleaning mechanism 403, which can clean the coated substrate 101 before the coated substrate 101 is rolled up to facilitate its reuse, and the cleaning mechanism 403 can be, for example, an ultrasonic cleaning device.

[0044] The travel of the coated substrate 101 is provided by the unwinding traction mechanism 106 and / or the winding traction mechanism 404, and the hoisting speeds of the two can be adjusted in coordination with each other to ensure that the coated substrate 101 has sufficient tension and real-time adjustment of the travel speed. It can be understood that the graphene oxide film production system also has a control cabinet 700, which is configured as the control brain of the entire system to receive relevant detection signals and feedback corresponding control instructions according to the corresponding detection signals and calculations, and as a basic design of the electric control, the present invention does not specifically limit it.

[0045] It is easy for those skilled in the art to understand that the above-mentioned advantageous methods can be freely combined and superimposed without conflict.

[0046] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention shall be included in the protection scope of the present invention. The above are only preferred embodiments of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and variations can be made without departing from the technical principles of the present invention, and these improvements and variations should also be regarded as the protection scope of the present invention.

Claims

1. A production system for graphene oxide membranes, characterized in that, it includes a feeding unit (100), an extrusion coating unit (200), a drying unit (300), and a winding unit (400). The coating substrate (101) is output by the feeding unit (100) and sequentially passes through the extrusion coating unit (200) and the drying unit (300) and is wound in the winding unit (400). The extrusion coating unit (200) includes a coating roller (1) and a material tank (3). The coating substrate (101) is tensionally connected to the coating roller (1). A doctor blade (2) is arranged adjacent to the coating roller (1). The doctor blade (2) is on the side of the coating substrate (101) away from the coating roller (1), and a coating gap is formed between the doctor blade (2) and the coating side of the coating substrate (101). The material tank (3) has a feed inlet and a discharge outlet. The discharge outlet is correspondingly arranged with the coating side of the coating substrate (101). An extrusion die head (4) is arranged at the feed inlet. The extrusion die head (4) can extrude the graphene oxide slurry into the material tank (3); wherein, the viscosity of the graphene oxide slurry is 10,000 mPa·s to 46,000 mPa·s; a rewetting unit (500) and a film peeling unit (600) are further arranged at the outlet of the drying unit (300). The rewetting unit (500) can rewet the dried graphene oxide membrane by means of water mist or steam. The film peeling unit (600) is between the rewetting unit (500) and the winding unit (400) and can peel the graphene oxide membrane from the coating substrate (101); the rewetting unit (500) includes a rewetting box (501). The coating substrate (101) divides the interior of the rewetting box (501) into an upper chamber (502) and a lower chamber (503). A steam spraying device (504) is arranged in the upper chamber (502), and / or a water mist spraying device (505) is arranged in the lower chamber (503). A corresponding heating component is arranged in the top wall of the box body of the rewetting box (501) to be able to heat it to prevent the condensation of steam on it to form water droplets.

2. The production system for graphene oxide membranes according to claim 1, characterized in that, the drying unit (300) further includes a first drying box (5). The first drying box (5) is downstream of the traveling direction of the coating substrate (101). A first over-roller (51) is provided at the inlet of the first drying box (5). The coating substrate (101) is tensioned between the coating roller (1) and the first over-roller (51), and an angle a is formed between the outlet direction of the coating substrate (101) and the horizontal plane, 8°≤a≤20°.

3. The production system for graphene oxide membranes according to claim 2, characterized in that, The connecting line between the axis of the doctor blade (2) and the axis of the coating roll (1) intersects the roll wall of the coating roll (1) at point B. The separation tangent point of the coating substrate (101) and the coating roll (1) is point C. Point B is on the side of point C closer to the material tank (3). The arc length between point B and point C is 5 mm to 10 mm.

4. The graphene oxide film production system according to claim 2, wherein, the extrusion coating unit (200) further includes a position adjustment component for adjusting the relative position of the doctor blade (2) with respect to the coating roll (1), thereby adjusting the coating gap.

5. The graphene oxide film production system according to claim 1, wherein, the coating substrate (101) is a breathable substrate.

6. The graphene oxide film production system according to claim 1, wherein, in the drying unit (300), a plurality of drying boxes are sequentially arranged adjacent to each other along the traveling direction of the coating substrate (101). The hot air flow velocity and the drying temperature in each drying box can be independently adjusted.

7. The graphene oxide film production system according to claim 6, wherein, the hot air flow velocity is getting higher and higher along the traveling direction of the coating substrate (101); and / or, the plurality of drying boxes are assembled to form an arched drying channel structure; and / or, the traveling speed of the coating substrate (101) is negatively correlated with the thickness of the graphene oxide film.

8. The graphene oxide film production system according to claim 7, wherein, the hot air flow velocity is divided into a low wind speed vl and a high wind speed vh, where 3 m / s ≤ vl ≤ 10 m / s, 20 m / s ≤ vh ≤ 30 m / s; and / or, the drying temperature in the drying box is T, 50 °C ≤ T ≤ 80 °C; and / or, the traveling speed of the coating substrate (101) is vd, 0.5 m / min ≤ vd ≤ 2 m / min.

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