Method for continuously producing high-barrier transparent graphene polyimide composite film

Abstract

The invention relates to the technical field of film preparation processes, in particular to a method for continuously producing a high-barrier transparent graphene polyimide composite film. According to the automatic production method of a series of roll-to-roll transparent flexible graphene polyimide composite films, a single-layer or multi-layer graphene film is produced through a chemical vapor deposition method and is loaded on polyimide, and the high barrier property of the graphene film is utilized; the barrier capacity of the whole sensor to small molecules such as oxygen, carbon dioxide and water vapor can be greatly improved, the barrier performance is extremely excellent, and the service life of the sensor can be greatly prolonged. The preparation process is simple, a large amount of personnel operation is not needed, large-scale production can be realized, and the labor cost and the production cost are greatly reduced.

Description

Technical Field

[0001] The invention relates to the technical field of film preparation technology, and in particular to a method for continuously producing a high-barrier transparent graphene polyimide composite film. Background Art

[0002] Graphene is a planar film composed of carbon atoms in a hexagonal honeycomb lattice with sp2 hybrid orbitals. It is also a two-dimensional material with a thickness of only one carbon atom, only 0.335nm, and is currently the thinnest but also the hardest nanomaterial in the world. It is almost completely transparent, with an absorptivity of only 2.3%. The thermal conductivity is as high as 5300W / m·K. Graphene has good electronic conductivity, and its electron mobility is higher than 15000cm2 / V·s at room temperature, while its resistivity is only 10-6Ω·cm, which is the material with the lowest resistivity in the world. It is also an excellent transparent conductive film with high light transmittance, high barrier, high conductivity, high flexibility, high mechanical strength, and high thermal conductivity. It has great advantages in the future field of flexible touch display.

[0003] Polyimide (PI) is a high-performance special engineering plastic, generally referring to thermosetting polyimide, while thermoplastic polyimide has many advantages over traditional thermosetting polyimide, the most notable of which is the improved toughness and thermal processing and molding capabilities. In the past few years, several new high-temperature resistant thermoplastic polyimides have been commercialized. Thermoplastic polyimide not only retains the high strength, high temperature resistance, chemical corrosion resistance, good dielectric properties, and radiation resistance of traditional thermosetting polyimide, but also improves processability. In addition to hot compression molding, it can also be molded by extrusion or injection. The main advantages of thermoplastic polyimide include outstanding processability, such as injection molding, extrusion, hot molding, spray molding, and no small molecules are released during processing, small shrinkage, high dimensional accuracy of parts, and excellent comprehensive mechanical performance, such as high modulus, impact resistance, creep resistance, and is an ideal structural functional material. It also has high heat deformation temperature, good heat resistance, and good mechanical strength in a wide range of high and low temperatures. Another advantage is that the chemical properties are stable and resistant to various types of oils and organic solvents. Finally, the material is pure and no small molecules that pollute the environment are released during processing and use. Thermosetting polyimide is chemically cross-linked and cannot be re-molded (i.e., cross-linked) after curing, while thermoplastic polyimide is a fully reacted linear polymer containing an imide group -CONCO- as part of the polymer chain. Since thermoplastic polyimides are not chemically cross-linked during processing, they can be re-molded and re-molded. Compared with traditional thermosetting polyimide, the production cost is significantly reduced. Compared with traditional thermosetting polyimide, the toughness of thermoplastic polyimide is much stronger than that of thermosetting polyimide. Compared with traditional thermosetting polyimide, the shrinkage rate is small, the dimensional accuracy of the product is high, and the comprehensive mechanical performance is excellent, such as high modulus, impact resistance, and creep resistance. Therefore, the probability of graphene film damage can be greatly reduced during the graphene transfer process. Moreover, due to the main advantages of thermoplastic polyimide, there are outstanding processability characteristics, such as injection molding, extrusion, hot molding, and spray molding. It has great advantages in large-scale production in the future. There is no release of small molecules that pollute the environment during processing and use. The transfer cleanliness of graphene film is significantly improved, and it is green and environmentally friendly. Because it is chemically stable, resistant to various oils and organic solvents, it is not easy to contact various solvents during the transfer process, which will cause the thermoplastic polyimide film to dissolve.

[0004] Since polyimide is commonly used in various flexible sensors and electronic components, and the barrier performance of polyimide is not strong, it cannot block small molecules such as oxygen, carbon dioxide, and water vapor, which greatly reduces the service life of the product. As a material with high barrier performance, graphene can be loaded on polyimide to effectively improve the barrier ability of polyimide and greatly improve the service life of its products. At present, the method of loading graphene on polyimide is mainly to add graphene filler to polyimide solution for dispersion. The dispersion problem of inorganic filler in polymer has always been a difficult problem in the industry. The interfacial compatibility between inorganic particles and organic polymers, the uniform dispersion and stability of inorganic particles in polymers also exist in polyimide composite materials. There are no functional groups on the surface of graphene, which is easy to agglomerate in the matrix resin, difficult to disperse evenly, and even re-deposit into graphite, which limits its application in polymer composite materials. And its transparency is also greatly reduced. Chemical vapor deposition is a method for producing graphene, which is divided into the growth and transfer of graphene. Graphene can be firmly combined with polyimide through strong π-π interactions, which can greatly reduce its breakage rate during the transfer process. Graphene prepared by chemical vapor deposition has high density and strong barrier properties, and because most of the layers are single layers, the light transmittance is extremely high. However, the main limiting factor is that the preparation process of graphene by chemical vapor deposition is complex, the conditions are demanding, and the production cost is high. Therefore, the development of a simple, easy-to-implement and low-cost method for preparing graphene composite films is an urgent problem to be solved. Summary of the invention

[0005] The present invention provides a method for continuously producing a high-barrier transparent graphene polyimide composite film, comprising the following steps: S1. The copper foil is fed into a continuous production device, and the copper foil is transported to a first oven for preheating and is ready for use after reaching the preheating temperature; S2. After reaching the preheating temperature, the copper foil is transported to the tube furnace, and methane, argon and hydrogen are introduced at high temperature for standby use after the reaction; S3. The copper foil with graphene grown in S2 is continuously transported to an electrostatic spray chamber for spraying polyimide, and then heated and cured in a second oven to obtain a copper foil - graphene - polyimide composite film for standby use; S4. The copper foil - graphene - polyimide composite film is further transported to an ammonium persulfate solution, the copper foil is removed by infiltration reaction, and then transported to an ultrapure aqueous solution for infiltration and cleaning to obtain a graphene - polyimide composite film; S5. The graphene-polyimide composite film can be rolled up after passing through a heat setting roller to obtain a high-barrier transparent graphene polyimide composite film.

[0006] In some embodiments, the preheating temperature of the first oven is 700-1100°C.

[0007] Preferably, the preheating temperature of the first oven is 1000°C.

[0008] In some embodiments, the heating temperature in the tube furnace is 700-1100°C.

[0009] Preferably, the heating temperature in the tube furnace is 1000°C.

[0010] In some embodiments, the flow rate of methane is 0.1-20 sccm, the flow rate of argon is 100-1000 sccm, and the flow rate of hydrogen is 5-100 sccm.

[0011] Preferably, the flow rate of methane is 5 sccm, the flow rate of argon is 1000 sccm, and the flow rate of hydrogen is 50 sccm.

[0012] In some embodiments, the reaction time in the tube furnace is 1-90 min.

[0013] Preferably, the reaction time in the tube furnace is 30 min.

[0014] In some embodiments, the thickness of the sprayed polyimide is 5-200 μm.

[0015] Preferably, the thickness of the sprayed polyimide is 60 μm.

[0016] Preferably, the sprayed polyimide is thermoplastic polyimide and thermosetting polyimide, more preferably thermosetting polyimide.

[0017] In some embodiments, the temperature of the second oven for heating and curing is 80-300°C.

[0018] Preferably, the temperature of the second oven for heating and curing is 250°C.

[0019] In some embodiments, the second oven performs heating and curing for 10-60 minutes.

[0020] Preferably, the second oven is heated and cured for 30 minutes.

[0021] In some embodiments, the concentration of ammonium persulfate is 0.1-1 mol / L, and the infiltration time is 15-60 min.

[0022] Preferably, the concentration of ammonium persulfate is 0.5 mol / L, and the infiltration time is 30 min.

[0023] In some embodiments, the immersion cleaning time in the ultrapure water solution is 5-60 minutes.

[0024] Preferably, the immersion cleaning time in the ultrapure water solution is 30 minutes.

[0025] The continuous production device of the present invention provides power through guide rollers during the conveying process.

[0026] The spacing between the heat setting rollers of the present invention is 5-200 μm, more preferably 60 μm.

[0027] Compared with the prior art, the present invention has the following beneficial effects: 1. The existing graphene prepared by chemical vapor deposition method needs to undergo a series of transfer operations before it can be transferred to the target substrate. The operation is cumbersome and requires high transfer experience of the operator. The present invention adopts an automated production method and does not require manual operation to directly obtain the graphene polyimide film.

[0028] 2. The automated production method of a series of roll-to-roll transparent flexible graphene polyimide composite films of the present invention produces single-layer or multi-layer graphene films loaded on polyimide by chemical vapor deposition. The high barrier properties of the graphene films can greatly improve the barrier ability of the entire sensor to small molecules such as oxygen, carbon dioxide, and water vapor. The barrier performance is extremely excellent and its service life can be greatly improved.

[0029] 3. The method of the present invention can be fully automated, the preparation process is simple, and a large number of personnel are not required for operation. It can be mass-produced, greatly reducing labor costs and production costs. In addition, since graphene has extremely high light transmittance, the lower the number of graphene layers, the stronger the light transmittance. The thickness of a single layer of graphene is only 0.335nm, and the increase in the thickness of the film is almost negligible, and a transparent and flexible graphene polyimide composite film can be produced. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a schematic diagram of the continuous production device in the present invention. DETAILED DESCRIPTION

[0031] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. Example 1

[0032] This embodiment provides a method for continuously producing a high-barrier transparent graphene polyimide composite film, comprising the following steps: S1. The copper foil is fed into a continuous production device, and the copper foil is transported to a first oven and preheated to 1000°C, and then the preheating temperature is reached and the foil is ready for use; S2. After reaching the preheating temperature, the copper foil is continuously transported to a tube furnace at a temperature of 1000°C, and 5 sccm of methane, 1000 sccm of argon and 50 sccm of hydrogen are introduced at high temperature, and the reaction is continued for 30 minutes and then used; S3. The copper foil with graphene grown in S2 is further transported to an electrostatic spray chamber to be sprayed with thermosetting polyimide, and then heated at 250° C. for 30 min in a second oven for curing. After curing, a copper foil-graphene-polyimide composite film having a polyimide layer thickness of 60 μm is obtained for standby use; S4. The copper foil - graphene - polyimide composite film is further transported to a 0.5 mol / L ammonium persulfate solution, infiltrated for 30 minutes to remove the copper foil, and then transported to an ultrapure aqueous solution for infiltration and cleaning for 30 minutes to obtain a graphene - polyimide composite film; S5. The graphene-polyimide composite film can be rolled up after passing through a heat-setting roller with a spacing of 60 μm, thereby obtaining a high-barrier transparent graphene polyimide composite film. Example 2

[0033] This embodiment provides a method for continuously producing a high-barrier transparent graphene polyimide composite film, comprising the following steps: S1. The copper foil is fed into a continuous production device, and the copper foil is transported to a first oven and preheated to 1000°C, and then the preheating temperature is reached and the foil is ready for use; S2. After reaching the preheating temperature, the copper foil is continuously transported to a tube furnace at a temperature of 950°C, and 1 sccm of methane, 1000 sccm of argon and 50 sccm of hydrogen are introduced at high temperature, and the reaction is continued for 30 minutes and then used; S3. The copper foil with graphene grown in S2 is further transported to an electrostatic spray chamber to be sprayed with thermosetting polyimide, and then heated at 250° C. for 30 min in a second oven for curing. After curing, a copper foil-graphene-polyimide composite film having a polyimide layer thickness of 60 μm is obtained for standby use; S4. The copper foil - graphene - polyimide composite film is further transported to a 0.5 mol / L ammonium persulfate solution, infiltrated for 30 minutes to remove the copper foil, and then transported to an ultrapure aqueous solution for infiltration and cleaning for 30 minutes to obtain a graphene - polyimide composite film; S5. The graphene-polyimide composite film can be rolled up after passing through a heat-setting roller with a spacing of 60 μm, thereby obtaining a high-barrier transparent graphene polyimide composite film. Example 3

[0034] This embodiment provides a method for continuously producing a high-barrier transparent graphene polyimide composite film, comprising the following steps: S1. The copper foil is fed into a continuous production device, and the copper foil is transported to a first oven and preheated to 1000°C, and then the preheating temperature is reached and the foil is ready for use; S2. After reaching the preheating temperature, the copper foil is continuously transported to a tube furnace at a temperature of 1070°C, and 20 sccm of methane, 1000 sccm of argon and 50 sccm of hydrogen are introduced at high temperature, and the reaction is continued for 30 minutes and then used; S3. The copper foil with graphene grown in S2 is further transported to an electrostatic spray chamber to be sprayed with thermosetting polyimide, and then heated at 250° C. for 30 min in a second oven for curing. After curing, a copper foil-graphene-polyimide composite film having a polyimide layer thickness of 60 μm is obtained for standby use; S4. The copper foil - graphene - polyimide composite film is further transported to a 0.5 mol / L ammonium persulfate solution, infiltrated for 30 minutes to remove the copper foil, and then transported to an ultrapure aqueous solution for infiltration and cleaning for 30 minutes to obtain a graphene - polyimide composite film; S5. The graphene-polyimide composite film can be rolled up after passing through a heat-setting roller with a spacing of 60 μm, thereby obtaining a high-barrier transparent graphene polyimide composite film. Comparative Example 1

[0035] This comparative example provides a method for continuously producing a polyimide film, comprising the following steps: S1. The copper foil is fed into an electrostatic spray chamber of a continuous production device to be sprayed with thermosetting polyimide, and then heated in an oven at 250°C for 30 minutes for curing. After curing, a copper foil-polyimide composite film having a polyimide layer thickness of 60 μm is obtained for standby use; S2. The copper foil - polyimide composite film is further transported to a 0.5 mol / L ammonium persulfate solution, infiltrated for 30 min to remove the copper foil, and then transported to an ultrapure aqueous solution for immersion and cleaning for 30 min to obtain a polyimide film; S3. The polyimide film can be rolled up after passing through a heat setting roller with a spacing of 60 μm to obtain a polyimide film. Comparative Example 2

[0036] This comparative example provides a method for continuously producing a high-barrier transparent graphene polyimide composite film, comprising the following steps: S1. The copper foil is fed into a continuous production device, and the copper foil is transported to a first oven and preheated to 700°C, and then the preheating temperature is reached and the foil is ready for use; S2. After reaching the preheating temperature, the copper foil is continuously transported to a tube furnace at a temperature of 700°C, and 5 sccm of methane, 1000 sccm of argon and 50 sccm of hydrogen are introduced at high temperature, and the reaction is continued for 30 minutes and then used; S3. The copper foil with graphene grown in S2 is further transported to an electrostatic spray chamber to be sprayed with thermosetting polyimide, and then heated at 250° C. for 30 min in a second oven for curing. After curing, a copper foil-graphene-polyimide composite film having a polyimide layer thickness of 60 μm is obtained for standby use; S4. The copper foil - graphene - polyimide composite film is further transported to a 0.5 mol / L ammonium persulfate solution, infiltrated for 30 minutes to remove the copper foil, and then transported to an ultrapure aqueous solution for infiltration and cleaning for 30 minutes to obtain a graphene - polyimide composite film; S5. The graphene-polyimide composite film can be rolled up after passing through a heat-setting roller with a spacing of 60 μm, thereby obtaining a high-barrier transparent graphene polyimide composite film. Comparative Example 3

[0037] This comparative example provides a method for continuously producing a high-barrier transparent graphene polyimide composite film, comprising the following steps: S1. The copper foil is fed into a continuous production device, and the copper foil is transported to a first oven and preheated to 1000°C, and then the preheating temperature is reached and the foil is ready for use; S2. After reaching the preheating temperature, the copper foil is continuously transported to a tube furnace at a temperature of 1000°C, and 5 sccm of methane, 1000 sccm of argon and 50 sccm of hydrogen are introduced at high temperature, and the reaction is continued for 30 minutes and then used; S3. The copper foil with graphene grown in S2 is further transported to an electrostatic spray chamber to be sprayed with thermosetting polyimide, and then heated at 250° C. for 30 min in a second oven for curing. After curing, a copper foil-graphene-polyimide composite film having a polyimide layer thickness of 60 μm is obtained for standby use; S4. The copper foil - graphene - polyimide composite film is further transported to a 0.1 mol / L ammonium persulfate solution, infiltrated for 30 minutes to remove the copper foil, and then transported to an ultrapure aqueous solution for infiltration and cleaning for 15 minutes to obtain a graphene - polyimide composite film; S5. The graphene-polyimide composite film can be rolled up after passing through a heat-setting roller with a spacing of 60 μm, thereby obtaining a high-barrier transparent graphene polyimide composite film. Performance Testing

[0038] The membrane materials prepared in the above examples and comparative examples were subjected to the following tests, and the results are shown in Table 1.

[0039] Water vapor transmission rate: Use W3 / 030 cup method water vapor transmission rate tester for testing.

[0040] Oxygen permeability: Use OTR-D3 oxygen permeability test system to test, put the sample into the permeation chamber, set the test conditions: use 5ml / min~25ml / min carrier gas to purge chamber A and chamber B for 30min, adjust the two valves upstream of the permeation chamber to allow oxygen to pass through chamber A and nitrogen to pass through chamber B, until the sensor signal is stable and record the signal value.

[0041] Table 1 <![CDATA[Water vapor transmission rate (g / (m 2. day))]]> Oxygen transmission rate (cm³ / m²·day·Pa) Example 1 0.0096 0.0072 Example 2 0.7043 0.5087 Example 3 0.0209 0.0190 Comparative Example 1 10.2204 8.0047 Comparative Example 2 8.2447 7.1155 Comparative Example 3 0.5412 0.4328 The above is a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for continuously producing a high-barrier transparent graphene polyimide composite film, characterized in that: The steps include: S1. The copper foil is fed into a continuous production device, and the copper foil is transported to a first oven for preheating and is ready for use after reaching the preheating temperature; S2. After reaching the preheating temperature, the copper foil is continuously transported to a tube furnace, and methane, argon and hydrogen are introduced at high temperature for standby use after the reaction; S3. The copper foil with graphene grown in S2 is further transported to the electrostatic spray chamber to spray polyimide, and then heated and cured in the second oven to obtain a copper foil - graphene - polyimide composite film for standby use; S4. The copper foil - graphene - polyimide composite film is further transported to an ammonium persulfate solution, the copper foil is removed by infiltration reaction, and then transported to an ultrapure aqueous solution for infiltration and cleaning to obtain a graphene - polyimide composite film; S5. The graphene-polyimide composite film can be rolled up after passing through a heat setting roller to obtain a high-barrier transparent graphene polyimide composite film.

2. The method according to claim 1, characterized in that The first oven is preheated to a temperature of 700-1100°C.

3. The method according to claim 1, characterized in that The heating temperature in the tube furnace is 700-1100°C.

4. The method according to claim 1, characterized in that: The flow rate of methane is 0.1-20 sccm, the flow rate of argon is 100-1000 sccm, and the flow rate of hydrogen is 5-100 sccm.

5. The method according to claim 1, characterized in that The reaction time in the tube furnace is 1-90 min.

6. The method according to claim 1, characterized in that The thickness of the sprayed polyimide is 5-200 μm.

7. The method according to claim 1, characterized in that The temperature of the second oven for heating and curing is 80-300°C.

8. The method according to claim 1, characterized in that The second oven is heated and cured for 10-60 minutes.

9. The method according to claim 1, characterized in that: The concentration of ammonium persulfate is 0.1-1 mol / L, and the infiltration time is 15-60 min.

10. The method according to claim 1, characterized in that The time for immersion cleaning in the ultrapure water solution is 5-60 minutes.

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