CN112871561A

CN112871561A - Graphene oxide film production system

Info

Publication number: CN112871561A
Application number: CN202110267403.2A
Authority: CN
Inventors: 周步存; 卢静; 周仁杰
Original assignee: Changzhou Fuxi Technology Co Ltd
Current assignee: Changzhou Fuxi Technology Co Ltd
Priority date: 2021-03-11
Filing date: 2021-03-11
Publication date: 2021-06-01

Abstract

The invention provides a graphene oxide film production system which comprises a feeding unit, an extrusion coating unit, a drying unit and a receiving unit, wherein a coating substrate is output by the feeding unit, sequentially passes through the extrusion coating unit and the drying unit and is wound in the receiving unit, the extrusion coating unit comprises a coating roller and a trough, the coating roller is connected with the coating substrate in a tensioning manner, a scraper is arranged adjacent to the coating roller, the coating roller is positioned on one side of the coating substrate, which is far away from the coating roller, a coating gap is formed between the scraper and the coating side of the coating substrate, the trough is provided with a feeding port and a discharging port, the discharging port is arranged corresponding to the coating side of the coating substrate, an extrusion die head is arranged at the feeding port, and the extrusion die head can extrude graphene oxide slurry into the trough. According to the invention, the graphene oxide slurry is obtained in the material tank, the liquid level of the slurry is smooth, and the slurry in the material tank is coated under the pressure action of the self weight to form a graphene oxide wet film with uniform thickness and large size.

Description

Graphene oxide film production system

Technical Field

The invention belongs to the technical field of graphene film production systems, and particularly relates to a graphene oxide film production system.

Background

In the prior art, the following two methods are generally adopted for coating the slurry on the substrate: one is extrusion coating, which is to spray slurry onto a substrate stretched vertically upwards, wherein an extrusion discharge lip is perpendicular to the coated substrate and is very close to the substrate, and the distance is related to the thickness of the coated wet film, the coating speed and the like, and is about tens to hundreds of micrometers, in this way, if the slurry is sprayed too thick, the slurry on the substrate can flow down vertically, so that the film surface is not uniform, and a wet film with large thickness cannot be obtained, therefore, the thickness of the film coated by adopting the method is generally not more than 1mm, but the thickness of the wet film with 1-4mm is required to be obtained by coating the graphene oxide slurry; the other is transfer coating, which is to scrape a certain thickness of film from the slurry onto a coating roll through a gap between the coating roll and a doctor blade, the coating roll is continuously rotated, then a backing roll with a coated substrate is leaned against the coating roll, and the film on the coating roll is transferred onto the coated substrate. That is, the graphene oxide film with a large thickness (1-4mm) and a uniform thickness cannot be formed in the extrusion coating and transfer coating modes in the prior art.

In addition, the graphene oxide film with a larger thickness has the problem of inconsistent drying degree in the drying process, so that the edge of the graphene film is dried more than the central part, the two sides of the graphene film are curled, and the flatness of the graphene film is poor; meanwhile, too high drying will cause the graphene oxide film to be easily damaged when being peeled from the substrate.

Disclosure of Invention

In order to solve at least one of the above problems, the present invention provides a graphene oxide film production system, comprising a feeding unit, an extrusion coating unit, a drying unit, and a receiving unit, wherein a coating substrate is output from the feeding unit, sequentially passes through the extrusion coating unit and the drying unit, and is wound in the receiving unit, the extrusion coating unit comprises a coating roller and a trough, the coating roller is connected with the coating substrate in a tensioning manner, a doctor blade is disposed adjacent to the applicator roll on a side of the coated substrate remote from the applicator roll, and a coating gap is formed between the scraper and the coating side of the coating substrate, the trough is provided with a feed inlet and a discharge outlet, the discharge port is arranged corresponding to the coating side of the coating substrate, the extrusion die head is arranged at the feed port, and the extrusion die head can extrude the graphene oxide slurry into the material groove.

Preferably, the drying unit comprises a first drying box, the first drying box is arranged at the downstream of the traveling direction of the coated substrate, a first roller is arranged at the inlet of the first drying box, the coated substrate is tensioned between the coating roller and the first roller, and the roller outlet direction of the coated substrate forms an included angle a which is more than or equal to 8 degrees and less than or equal to 20 degrees with the horizontal plane.

Preferably, a connecting line between the axis of the scraper and the axis of the coating roller intersects with the roller wall of the coating roller at a point B, a point C is a point C which is a tangent point of the coating substrate to the coating roller, the point B is located at a side of the point C close to the trough, and an arc length between the point B and the point C is 5mm to 10 mm.

Preferably, the extrusion coating unit further comprises a position adjusting member for adjusting a relative position of the blade with respect to the coating roller, thereby adjusting the coating gap.

Preferably, the coated substrate is a breathable substrate.

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

Preferably, the hot gas stream is increasingly high in velocity along the direction of travel of the coated substrate; and/or a plurality of drying boxes are assembled to form an arch-shaped drying tunnel structure; and/or, the travel speed of the coated substrate is inversely related to the thickness of the graphene oxide film.

Preferably, the wind speed of the hot air flow is divided into a low wind speed vl and a high wind speed vh, wherein vl is more than or equal to 3m/s and less than or equal to 10m/s, and vh is more than or equal to 20m/s and less than or equal to 30 m/s; and/or the drying temperature in the drying box is T, wherein T is more than or equal to 50 ℃ and less than or equal to 80 ℃; and/or the traveling speed of the coating substrate is vd which is more than or equal to 0.5m/min and less than or equal to 2 m/min.

Preferably, a moisture returning unit and a film stripping unit are further arranged at an outlet of the drying unit, the moisture returning unit can be used for returning moisture to the dried graphene oxide film in a water mist or steam mode, and the film stripping unit is located between the moisture returning unit and the material receiving unit and can be used for stripping the graphene oxide film from the coating substrate.

Preferably, the wet returning unit comprises a wet returning box, the coating substrate divides the interior of the wet returning box into an upper chamber and a lower chamber, a steam spraying device is arranged in the upper chamber, and/or a water spraying device is arranged in the lower chamber.

According to the graphene oxide film production system, the extrusion coating unit extrudes and feeds graphene oxide slurry into the trough by utilizing the extrusion of the extrusion die head, the slurry with a flat liquid level can be obtained in the trough, and the slurry in the trough flows and is coated on the coating side of the coating substrate through the coating gap between the scraper and the coating side of the coating substrate under the pressure of the self weight, so that a graphene oxide wet film with uniform thickness and large thickness is formed.

Drawings

Fig. 1 is a schematic structural view of a graphene oxide film production system according to an embodiment of the present invention;

FIG. 2 is an enlarged view of a portion of FIG. 1 at A;

FIG. 3 is an enlarged view of a portion of FIG. 1 at B;

FIG. 4 is a partial schematic view of the extrusion coating unit of FIG. 1;

FIG. 5 is an enlarged view of a portion of FIG. 4 at C;

FIG. 6 is a schematic view of a position adjusting part of the extrusion coating unit;

FIG. 7 is a schematic structural view (snap-fit state) of an embodiment of the rewetting unit of FIG. 1

Fig. 8 is a schematic structural view of the dehumidifying unit in fig. 7 in an opened state.

The reference numerals are represented as:

1. a coating roll; 2. a scraper; 3. a trough; 4. an extrusion die head; 5. a first drying box; 51. a first roller; 61. mounting a plate; 62. swinging arms; 63. a motor; 64. a lifting cylinder; 65. a limiting member; 7. a film thickness detection section; 100. a feeding unit; 101. coating a substrate; 102. a double-station unwinding mechanism; 103. a material storage mechanism; 104. a material receiving mechanism; 105. a double-sided cleaning mechanism; 106. an unwinding traction mechanism; 107. a graphene oxide film; 200. an extrusion coating unit; 300. a drying unit; 400. a receiving unit; 401. a first double-station winding mechanism; 402. a second double-station winding mechanism; 403. a cleaning mechanism; 404. a winding traction mechanism; 500. a rewetting unit; 501. a moisture reducing box; 502. an upper chamber; 503. a lower chamber; 504. a steam spraying device; 505. a water spray device; 600. a film peeling unit; 700. a control cabinet.

Detailed Description

Referring to fig. 1 to 8 in combination, according to an embodiment of the present invention, there is provided a graphene oxide film production system, including a feeding unit 100, an extrusion coating unit 200, a drying unit 300, and a material receiving unit 400, where a coating substrate 101 is output from the feeding unit 100, passes through the extrusion coating unit 200 and the drying unit 300 in sequence, and is wound in the material receiving unit 400, the extrusion coating unit 200 includes a coating roller 1 and a trough 3, the coating roller 1 is connected with the coating substrate 101 in a tensioned manner, a scraper 2 is disposed adjacent to the coating roller 1, the coating roller 1 is located on a side of the coating substrate 101 away from the coating roller 1, a coating gap is formed between the scraper 2 and the coating side of the coating substrate 101, the trough 3 has a feeding port and a discharging port, and the discharging port is disposed corresponding to the coating side of the coating substrate 101, the feeding port is provided with an extrusion die head 4, and the extrusion die head 4 can extrude the graphene oxide slurry into the trough 3. In the technical scheme, the extrusion coating unit 200 extrudes and feeds the graphene oxide slurry into the material tank 3 by using the extrusion of the extrusion die head 4, so that the slurry with a flat liquid level can be obtained in the material tank 3, the slurry in the material tank 3 can be coated on the coating side of the coating substrate 101 through the coating side of the scraper 2 and the coating roller 1 through flowing in the coating gap between the scraper 2 and the coating roller 1 under the action of the self-weight pressure, so as to form a graphene oxide wet film with a uniform thickness, and it can be understood that the extrusion die head 4 extrudes the slurry from the cavity in the extrusion die head to the discharge port of the extrusion die head by using a larger pressure, and because the internal pressure is consistent, the outflow amount of the slurry at each position of the discharge port is equal, so that a flat slurry liquid level can be formed in the material tank 3, and the flat liquid level of the slurry can make the coating pressure caused by the self-weight of the slurry consistent, and then guaranteed that rete thickness is even, and further can understand, when the thick liquids liquid level in the silo 3 is uneven, can cause the thick liquids in the silo 3 to transmit the inconsistent pressure to the coating department, lead to coating thickness inconsistent and great (test proves, the extrusion coating unit 200 that adopts this application can coat the wet membrane that forms 1mm ~ 4mm thickness), cause the emergence of inhomogeneous phenomenon, because the viscosity of oxidized graphene thick liquids is big, the conventional material loading mode can't obtain level liquid level in the silo 3, and this defect among the prior art then can be overcome to extrusion die head 4 in this application.

In some embodiments, in order to obtain a wet film thickness of 1-4mm, the viscosity of the graphene oxide slurry is controlled to be more than 10000mpa.s and less than 46000mpa.s, so that on one hand, excessive flowing of the wet film slurry can be effectively avoided, and the film thickness is not uniform, and on the other hand, internal bubbles are not easy to remove due to too high viscosity of the slurry. The graphene oxide slurry is low in solid content, only contains 2-8% of graphene oxide, and the balance is solvent (the main solvent is deionized water).

The drying unit 300 comprises a first drying box 5, the first drying box 5 is located at the downstream of the traveling direction of the coated substrate 101 and is used for drying the formed graphene oxide wet film, a first roller 51 is arranged at the inlet of the first drying box 5, the coated substrate 101 is tensioned between the coating roller 1 and the first roller 51, and an included angle a is formed between the roller outlet direction of the coated substrate 101 and the horizontal plane, wherein the included angle a is more than or equal to 8 degrees and less than or equal to 20 degrees. Specifically, if a is greater than 20 °, the wet film flows due to certain fluidity, and the film layer is not uniform, and if a is less than 8 °, the wet film has no leveling process, and the film surface has fine texture, and the film layer is not uniform enough.

Preferably, a connecting line between the axis of the scraper 2 and the axis of the coating roller 1 intersects with a roller wall of the coating roller 1 at a point B, a release tangent point of the coating substrate 101 and the coating roller 1 is a point C, the point B is located at a side of the point C close to the trough 3, and an arc length between the point B and the point C is 5mm to 10 mm. If be less than 5mm, other interference such as external vibration can influence thick liquids coating, appear the striae, if be greater than 10mm, thick liquid in silo 3 is difficult to go up to the scraper mouth department of scraper 2, does not form the wet film that thickness is thick.

Further, the graphene oxide film coating system further includes a position adjusting member for adjusting a relative position of the doctor blade 2 with respect to the coating roller 1, thereby adjusting the coating gap. That is, the relative position between the doctor blade 2 and the coating roller 1 can be changed by the operation of the position adjusting component, so as to adjust the formation thickness of the wet film, and further enable the coating system to meet the manufacturing requirements of graphene oxide films with different thicknesses.

As a specific embodiment of the position adjusting component, the position adjusting component includes a mounting plate 61, a swing arm 62 is pivotally connected to the mounting plate 61, the doctor blade 2 is rotatably and drivably connected to the swing arm 62, a motor 63 is disposed at one end of the swing arm 62, 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 for driving the position change of the doctor blade 2, and more specifically, the lifting cylinder 64 is used for driving the lifting and dropping of the doctor blade 2, and the motor 63 is used for precisely adjusting the distance between the doctor blade 2 and the coating roller 1.

Preferably, the mounting plate 61 is further provided with a limiting member 65, and the limiting member 65 is located on one side of the swing arm 62 away from the coating roller 1, so as to limit the lifting displacement range of the swing arm 62.

In some embodiments, a film thickness detection component 7 is disposed at the coating substrate 101 between the coating roller 1 and the first roller 51, and the film thickness detection component 7 can be, for example, an X-ray test system, and can move laterally to detect the thickness of the whole coating surface, and can control the operation of the motor 63 according to the detected real-time thickness, so as to adjust the relative position of the doctor blade 2 and the coating roller 1 in real time, and further ensure the uniformity of the thickness of the coating film.

Preferably, the applicator roll 1 is pivotally connected to the mounting plate 61; and/or the 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 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 among the components is more stable, and the structure is simpler and more compact.

In the prior art, the graphene oxide slurry is coated into a wet film and then enters the subsequent drying unit 300 for drying, the surface of the wet film is firstly dried in the drying process, the surface of the dried film prevents the internal moisture from being discharged, so that the wet film is difficult to dry and takes longer to dry, and in order to improve the drying efficiency of the wet film, preferably, the coating substrate 101 is a breathable substrate, and the breathable substrate can be one of PP monofilament woven cloth, PE monofilament woven cloth, and stainless steel mesh belt, so that the graphene oxide wet film can be dried on both sides simultaneously, and the drying efficiency is greatly improved.

In some embodiments, a plurality of drying boxes (including the first drying box 5 described above) are sequentially and adjacently arranged in the drying unit 300 along the traveling direction of the coating substrate 101, the specific length of the drying boxes and the number of the drying boxes can be selected according to actual conditions, and the wind speed of the hot air flow and the drying temperature in each drying box can be independently adjusted, so that the adjustment can be performed at any time according to the drying degree of the graphene oxide wet film. Furthermore, the wind speed of the hot gas flow is higher and higher along the traveling direction of the coating substrate 101, that is, the drying wind speed of the graphene oxide wet film entering the drying unit 300 is relatively lowest, and the drying wind speed of the graphene oxide film to be output from the drying unit 300 is relatively highest, which can ensure that the graphene oxide wet film is not disturbed by the airflow with the excessive wind speed when the mobility is relatively high, thereby ensuring the final appearance quality of the graphene oxide film 107, specifically, the wind speed of the hot gas flow is divided into a low wind speed vl and a high wind speed vh, wherein vl is not less than 3m/s and not more than 10m/s, vh is not less than 20m/s and not more than 30m/s, and the appearance quality of the graphene oxide film 107 can be ensured while ensuring the 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, and in some embodiments, the length of the drying unit 300 (i.e., the total drying channel length of the drying boxes) is designed to be more than 64 m.

The inventors have found through research that the traveling speed of the coated substrate 101 is inversely related to the thickness of the graphene oxide film 107, that is, the larger the thickness of the graphene oxide film 107 is, the lower the traveling speed of the coated substrate 101 should be used to ensure thorough drying, and specifically, when the slurry solid content is 5%, the gram weight of the graphene oxide film obtained by different wet coating film thicknesses and the corresponding coating drying speed (i.e., the speed at which the coating system operates) are specifically referred to in the following table.

Coated wet film thickness-μm	Gram weight/g/m of graphene oxide film after drying²	Speed/m/min of coating system operation
			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

In the aspect of temperature control, a graphene oxide film with few oriented assembly defects can be obtained at a lower drying temperature, but due to high cost and lack of competitiveness, the oxygen-containing functional groups in the graphene oxide film are decomposed at a higher temperature, and the graphene oxide film is prone to generate bulge and other poor appearances, so that the drying temperature in the drying box is designed to be T, wherein T is more than or equal to 50 ℃ and less than or equal to 80 ℃; and/or the advancing speed of the coating substrate 101 is vd which is not less than 0.5m/min and not more than vd which is not less than 2m/min, and the advancing speed within the range can ensure that the graphene oxide film is damaged possibly caused by the excessively fast peeling process of the subsequent film while the drying efficiency is considered.

As can be seen from the foregoing, during the drying process of the graphene oxide wet film in the drying unit 300, the upper surface of the wet film is dried firstly, at the moment, the moisture in the wet film is forced to be separated out from the two sides (namely the two sides of the thickness) of the wet film, so that the wet film is dried firstly at the two sides of the whole width, dried in the middle and then dried, and is not uniformly dried, and thus both sides (right and left sides in the traveling direction) of the film, and in order to weaken the curling caused by such drying unevenness, it is preferable that a plurality of the drying boxes are assembled to form an arch-shaped drying tunnel structure, as can be understood, the rollers arranged in the roller type film winding machine have height difference in the height direction, the arched drying channel has certain curvature, the distance that the film is always horizontal is reduced, the film between the two rollers and the film between the adjacent rollers are not parallel, and the two sides of the film are tightened, so that the curling is reduced.

Further, a humidifying unit 500 and a film peeling unit 600 are further provided at an outlet of the drying unit 300, the humidifying unit 500 can humidify the dried graphene oxide film by means of water mist or steam, so that a part dried by the drying unit 300 can be wetted and softened, and the subsequent graphene oxide film 107 can be peeled from the coating substrate 101 more smoothly, and the integrity of the graphene oxide film 107 after peeling is ensured, and the film peeling unit 600 is located between the humidifying unit 500 and the material receiving unit 400, and can peel the graphene oxide film from the coating substrate 101. It will be appreciated that a corresponding stripping blade is included in the film stripping unit 600.

As a specific embodiment of the wet returning unit 500, as shown in fig. 7 and 8, the wet returning unit 500 includes a wet returning box 501, the coating substrate 101 divides the interior of the wet returning box 501 into an upper chamber 502 and a lower chamber 503, a steam spraying device 504 is disposed in the upper chamber 502, and/or a water spraying device 505 is disposed in the lower chamber 503, so that the upper and lower surfaces of the graphene oxide film 107 can be simultaneously wetted, and the film has uniform flexibility as much as possible, and it can be understood that the steam spraying device 504 and the water spraying device 505 are both in controllable through connection with corresponding external steam or atomizing components, which is not described herein again. It is emphasized that the steam-jet device 504 arranged in the upper chamber 502 can prevent water mist from forming an aggregate on the upper surface of the graphene oxide film 107 and adversely affecting the appearance of the graphene oxide film as much as possible. Further, a corresponding heating component (e.g., a heating film) may be disposed in the top wall of the humidifying box 501 to heat the humidifying box and prevent the steam from condensing thereon to form water drops. The moisture box 501 may also be designed to have a box (not referenced) and a cover (not referenced) hinged to the box to allow the cover to be opened when desired.

In some embodiments, the feeding unit 100 includes a double-station unwinding mechanism 102 and a storage mechanism 103, the double-station unwinding mechanism 102 is adopted to enable the coating substrate 101 to be replaced without stopping, so that the coating efficiency is improved, a receiving mechanism 104 (a sewing machine can be specifically adopted) is further arranged between the double-station unwinding mechanism 102 and the storage mechanism 103, the receiving mechanism 104 can sew the coating substrates 101 at two ends, generally speaking, the coating substrates 101 are mostly resin cloth with the thickness of 0.35mm to 0.5mm, and generally, an adhesive tape adopted is not firm in adhesion and easy to break in a drying oven, so that sewing is adopted. Further, storage mechanism 103 with still be equipped with two-sided clean mechanism 105 between the extrusion coating unit 200, storage mechanism 103 can coating basement 101 gets into set up the multiunit before the extrusion coating unit 200, when the coating basement is changed, the material in the storage mechanism guarantees that the coating is continuous incessantly, and under general conditions, guarantee that storage length 5m ~ 10m can. The double-sided cleaning mechanism 105 is specifically formed, for example, by using two opposing adhesive tape rollers between which the dust on the coated substrate 101 is removed while passing.

In some embodiments, the material receiving unit 400 includes a first two-station winding mechanism 401 and a second two-station winding mechanism 402, wherein the first two-station winding mechanism 401 is used for winding the graphene oxide film, and the second two-station winding mechanism 402 is used for winding the coated substrate 101. The material receiving unit 400 further includes a cleaning mechanism 403 capable of cleaning the coated substrate 101 before the coated substrate 101 is taken up to facilitate its reuse, and the cleaning mechanism 403 may be, for example, an ultrasonic cleaning device.

The travel of the coated substrate 101 is provided by the unwind pulling mechanism 106 and/or the wind pulling mechanism 404, and the winding 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 further has a control cabinet 700, which is configured to receive the relevant detection signal and feed back the corresponding control command according to the corresponding detection signal and after operation as a basic design in the aspect of electrical control, as a control brain of the whole system, and the present invention is not limited thereto.

It is readily understood by a person skilled in the art that the advantageous ways described above can be freely combined, superimposed without conflict.

The present invention is not limited to the above preferred embodiments, and any modifications, equivalent substitutions and improvements made within the spirit and principle of the present invention should be included in the protection scope of the present invention. The above is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, several improvements and modifications can be made without departing from the technical principle of the present invention, and these improvements and modifications should also be regarded as the protection scope of the present invention.

Claims

1. The graphene oxide film production system is characterized by comprising a feeding unit (100), an extrusion coating unit (200), a drying unit (300) and a receiving unit (400), wherein a coating substrate (101) is output by the feeding unit (100), 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 trough (3), the coating substrate (101) is connected to the coating roller (1) in a tensioning manner, a scraper (2) is arranged adjacent to the coating roller (1), the coating roller (1) is positioned on one side of the coating substrate (101) far away from the coating roller (1), a coating gap is formed between the scraper (2) and the coating side of the coating substrate (101), and the trough (3) is provided with a feeding hole and a discharging hole, the discharge port is arranged corresponding to the coating side of the coating substrate (101), the extrusion die head (4) is arranged at the feed port, and the extrusion die head (4) can extrude the graphene oxide slurry into the trough (3).

2. The graphene oxide film production system according to claim 1, wherein the extrusion coating unit (200) further comprises a first drying box (5), the first drying box (5) is located downstream of the traveling direction of the coated substrate (101), a first passing roller (51) is arranged at an inlet of the first drying box (5), the coated substrate (101) is tensioned between the coating roller (1) and the first passing roller (51), and an included angle a is formed between the roll outlet direction of the coated substrate (101) and a horizontal plane, wherein the included angle a is more than or equal to 8 degrees and less than or equal to 20 degrees.

3. The graphene oxide film production system according to claim 2, wherein a connecting line between the axis of the doctor blade (2) and the axis of the coating roller (1) intersects with a roller wall of the coating roller (1) at a point B, a point C of tangency of the coating substrate (101) to the coating roller (1) is a point B, the point B is located on a side of the point C close to the trough (3), and an arc length between the point B and the point C is 5mm 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 means for adjusting a relative position of the doctor blade (2) with respect to the coating roller (1), thereby adjusting the coating gap.

5. The graphene oxide film production system of claim 1, wherein the coated substrate (101) is a gas permeable substrate.

6. The graphene oxide film production system according to claim 1, wherein a plurality of drying boxes are disposed in the drying unit (300) in close proximity in the traveling direction of the coated substrate (101), and a hot air flow speed and a drying temperature in each drying box can be independently adjusted.

7. The graphene oxide film production system according to claim 6, wherein the hot gas flow is increasingly high in wind speed along the traveling direction of the coated substrate (101); and/or a plurality of drying boxes are assembled to form an arch-shaped drying tunnel structure; and/or the speed of travel of the coated substrate (101) is inversely related to the thickness of the graphene oxide film.

8. The graphene oxide film production system according to claim 7, wherein the wind speed of the hot gas flow is divided into a low wind speed vl and a high wind speed vh, wherein vl is equal to or greater than 3m/s and equal to or less than 10m/s, vh is equal to or greater than 20m/s and equal to or less than 30 m/s; and/or the drying temperature in the drying box is T, wherein T is more than or equal to 50 ℃ and less than or equal to 80 ℃; and/or the coating substrate (101) has a traveling speed vd of 0.5m/min or more and vd of 2m/min or less.

9. The graphene oxide film production system according to claim 1, wherein a rewetting unit (500) and a film peeling unit (600) are further provided at an outlet of the drying unit (300), the rewetting unit (500) is capable of rewetting the dried graphene oxide film by means of water mist or steam, and the film peeling unit (600) is located between the rewetting unit (500) and the material receiving unit (400) and is capable of peeling the graphene oxide film from the coated substrate (101).

10. The graphene oxide film production system according to claim 9, wherein the rewetting unit (500) includes a rewetting tank (501), and the coating substrate (101) partitions an interior of the rewetting tank (501) into an upper chamber (502) and a lower chamber (503), and a steam spraying device (504) is provided in the upper chamber (502), and/or a water spraying device (505) is provided in the lower chamber (503).