Graphene composite film and preparation method thereof

Abstract

The application discloses a graphene composite film material and a preparation method thereof. The graphene composite film material is characterized in that at least one graphene layer is arranged on a high-molecular transparent composite film, the high-molecular transparent composite film is composed of a high-molecular substrate and a polymer adhesive layer, and the high-molecular transparent composite film and the graphene layer are connected through an adhesive. If there are multiple graphene layers on the composite film, the adjacent graphene layers are directly connected without any adhesive. The graphene composite film prepared by the application breaks through the limitation of the water vapor and oxygen barrier performance of the previous high-molecular material, has excellent light transmittance and flexibility, and can meet the application requirements of OLED device packaging, medical packaging and food packaging.

Description

Technical Field

[0001] This invention belongs to the field of composite material preparation, and relates to a graphene composite film and its preparation method. Background Technology

[0002] Organic light-emitting diodes (OLEDs) are a new type of light-emitting device. Compared with LCDs, OLED displays have advantages such as being thinner and lighter, more flexible, having higher luminous efficiency, lower power consumption, higher resolution, wider viewing angles, and faster response times, making them promising for applications in the display and lighting fields.

[0003] To ensure the required lifespan of OLED devices, the water vapor permeation rate (WVTR) of the device encapsulation material is typically required to be less than 10. -6 g / (m 2 • 24hr), Oxygen Osmosis Rate (OTR) less than 10 -5 cc / (m 2 • 24hr). While polymer materials have the advantages of being lightweight, flexible, and easy to process, WVTR and OTR are typically around 10. -1 ~40g / (m 2 ·24hr) and 10 -2 ~10 2 cc / (m 2 Within a 24hr range. Therefore, to apply flexible polymer composite films to OLED encapsulation, it is necessary to first improve the gas barrier properties of the film without reducing its light transmittance.

[0004] Several methods exist for improving the barrier properties of polymers using graphene. For example: Patent application CN105313433A, entitled "A method for improving the performance of graphene composite gas barrier membranes"; patent application CN103682054B, entitled "A method for packaging flexible optoelectronic devices based on graphene"; patent application CN103692743B, entitled "A graphene composite thin film material and its preparation method"; and patent application CN109830615B, entitled "A water vapor barrier membrane structure for flexible OLED packaging." Furthermore, patent application CN101364646B, entitled "A fuel cell electrode with a water vapor barrier layer," also mentions using highly conductive carbon powder and hydrophobic resin as the water vapor barrier layer, with a thickness of 0.12–0.70 mm. Summary of the Invention

[0005] Graphene, due to its unique six-membered ring lattice structure, possesses excellent gas barrier properties, flexibility, and light transmittance; the light transmittance of a single layer of graphene can reach 97%. Therefore, tightly combining graphene with flexible polymer materials can effectively improve the barrier properties of thin films while ensuring their light transmittance and flexibility. With the increasing maturity of chemical vapor deposition (CVD) for growing graphene on metal substrates, graphene transfer technology has become particularly important. How to transfer graphene onto polymer substrates without damage, wrinkles, or contamination has become crucial for guiding OLED applications.

[0006] Existing methods for improving polymer barrier properties using graphene employ two thin films encapsulated on top and bottom of the graphene, increasing the thickness of the film / barrier layer, reducing light transmittance, and limiting the application range. Some technologies even directly encapsulate OLED devices between the two materials, further restricting the use of OLED devices. In addition, some methods use resin as a water and oxygen barrier layer, but the high rigidity of resin weakens the deformation capability of the composite film, making the material prone to damage during deformation. Other methods use organic solvents for adhesive removal, which not only pollutes the environment but also significantly increases the cost of the method, and subsequent waste liquid treatment also increases expenses.

[0007] To address the aforementioned technical problems, this invention provides a graphene thin film material and its preparation method, using large-area single-layer or multi-layer graphene as a gas barrier functional layer and a polymer substrate as a transparent support layer. The two materials are composited using an adhesive layer and a liquid binder on the polymer composite film to form a composite material with high light transmittance and excellent gas barrier properties.

[0008] The purpose of this invention is to provide a graphene composite film material, wherein the composite film material includes at least one layer of graphene disposed on a polymer transparent composite film, the polymer transparent composite film being composed of a two-layer structure of a polymer substrate and a polymer adhesive layer; the polymer adhesive layer and the graphene layer of the polymer transparent composite film are connected by an adhesive. This invention, by employing a polymer transparent composite film with a two-layer structure of a polymer substrate and a polymer adhesive layer, and with the polymer adhesive layer and graphene layer connected by an adhesive, achieves a composite of only one layer of polymer transparent composite film and graphene layer, ensuring a low water vapor permeation rate without reducing light transmittance or flexibility.

[0009] According to one embodiment of the present invention, the solute of the adhesive is one or more selected from rosin, borneol, polypropylene carbonate (PPC), polymethyl methacrylate, polymethyl glutarimide, polycarbonate, and polysiloxane, preferably PPC; the solvent of the adhesive is one of anisole, ethyl lactate, and ethyl acetate, preferably anisole. Using the above adhesive can achieve good conformal bonding between graphene and the transparent polymer composite film, thereby ensuring the integrity of the graphene layer and achieving a low water vapor permeation rate without reducing light transmittance.

[0010] According to one embodiment of the present invention, the number-average molecular weight of the solute in the adhesive is 5w-30w. Within this range, the graphene exhibits better integrity, which is beneficial for improving the material's water vapor barrier properties.

[0011] According to one embodiment of the present invention, the adhesive is prepared by: placing the solute into a brown glass bottle and sealing it, and baking it in an oven for 8-24 hours; then injecting the solvent into the glass bottle, wherein the mass ratio of the solute in g to the volume of the solvent in ml is 1:10, stirring for 5-12 hours, and finally ultrasonically vibrating the resulting solution to obtain the adhesive.

[0012] According to one embodiment of the present invention, the baking temperature in the oven is 30-80℃, preferably 50℃; the stirring temperature is 30-80℃, preferably 60℃; and the ultrasonic oscillation frequency is 40kHz for 3 hours.

[0013] According to one embodiment of the present invention, the composite film material includes multiple layers of graphene disposed on a polymer transparent composite film, preferably a double layer; adjacent graphene layers are directly connected without the aid of adhesive.

[0014] According to one embodiment of the present invention, the polymer substrate is composed of one or more of polyethylene terephthalate (PET), polyethylene (PE), cellulose triacetate (TAC), polyvinyl alcohol (PVA), polyvinyl chloride (PVC), and polyethylene naphthalate (PEN); preferably, the thickness of the polymer substrate is 50-200 μm; and / or

[0015] The polymer adhesive layer is composed of one or more of silicone resin, epoxy resin, polyacrylate, and ethylene-vinyl acetate copolymer; preferably, the thickness of the polymer adhesive layer is 1-100 μm.

[0016] According to one embodiment of the present invention, the single-layer graphene or the single-layer graphene constituting multilayer graphene is a single-layer graphene grown on a metal substrate by vapor deposition; the metal substrate is one of Cu, Ni, Pt, Ru or an alloy thereof, preferably copper foil.

[0017] Another object of the present invention is to provide a method for preparing the above-mentioned graphene composite film material, comprising the following steps:

[0018] (1) Preparation of adhesive: The solute is placed in a brown glass bottle and sealed, and baked in an oven for 8h-24h; then the solvent is injected into the glass bottle, and the mass ratio of the solute in g to the volume of the solvent in ml is 1:10. Stir for 5-12h, and finally the resulting solution is ultrasonically vibrated to obtain the adhesive.

[0019] (2) Preparation of graphene layer: Large-area monolayer graphene grown on metal substrate by vapor deposition;

[0020] (3) Adhesion between graphene layer and polymer transparent film: Apply adhesive to the side of the metal substrate where graphene is grown; after heating and curing, roll and press the side coated with adhesive to the polymer adhesive layer side of the polymer transparent composite film; then remove the metal substrate, wash and dry the remaining composite film to obtain a composite film material with a single layer of graphene.

[0021] (4) The graphene-containing side of the composite film material with single-layer graphene obtained in step (3) is hot-rolled and pressed with the graphene-containing side of another metal substrate with graphene grown on it. Then the resulting composite film is heated and statically pressed for 12-48 hours. Finally, the metal substrate is removed, and the remaining composite film is washed and dried. Repeat this process multiple times to obtain a composite film material with multiple layers of graphene.

[0022] Using the above preparation method, the polymer adhesive layer and the graphene layer of the transparent polymer composite film are connected by an adhesive. With the help of the polymer adhesive layer and the adhesive, the polymer substrate and the graphene are tightly bonded, thereby preventing the graphene from wrinkling and breaking during the transfer process. This ensures a low water vapor permeation rate without reducing the light transmittance.

[0023] This invention uses a roll forming method to achieve bonding between graphene and composite film materials and multilayer graphene, which can achieve tight conformal bonding between layers. The preparation process is simple, suitable for large-scale industrial production, and is more conducive to improving the water vapor barrier properties of composite materials.

[0024] According to one embodiment of the present invention, the method for removing the metal substrate is an etching method, and the etching solution is a solution of one or more of ferric chloride, sodium persulfate, ammonium persulfate, hydrogen peroxide, hydrochloric acid or nitric acid; the concentration of the etching solution is 0.5 mol / L to 2.0 mol / L.

[0025] According to one embodiment of the present invention, the method for removing the metal substrate is an electrochemical bubbling method, using platinum or graphite as the anode, the metal substrate as the cathode, and the electrolyte being a solution of one or more of sodium hydroxide, potassium hydroxide, sodium nitrate, potassium nitrate, and ammonium nitrate. The concentration of the electrolyte is 0.5 mol / L to 2.0 mol / L, and the current during bubbling is 0.1-3 A.

[0026] According to one embodiment of the present invention, the temperature of heating the composite membrane under static pressure in step (4) above is 30 to 80°C.

[0027] Another object of the present invention is to provide the application of the above-mentioned composite thin film material or the composite thin film material prepared by the above-mentioned preparation method in the fields of OLED device packaging, pharmaceuticals, and food packaging.

[0028] The advantages of this invention are as follows: Through the aid of a selected adhesive and a special roll-pressing process, a thin film material is created by bonding a single layer of transparent polymer composite film to a graphene layer. This film material exhibits high light transmittance, high flexibility, and extremely low water vapor permeation rate. More preferably, due to the direct and tight stacking of multiple graphene layers, even if gas molecules pass through minor breaks in a single graphene layer, they will be blocked by the intact layers of the next layer at extremely short intervals. Therefore, the graphene composite film prepared by this invention overcomes the limitations of the barrier properties of previous polymer materials, while possessing excellent light transmittance and flexibility. It can meet the application requirements of OLED device encapsulation, pharmaceuticals, food packaging, and other applications, and has great promotional value and application prospects. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the structure of the graphene composite film material of the present invention.

[0030] Figure 2 This is the three-dimensional structure of the graphene composite film material of the present invention.

[0031] Figure 3 This is a schematic diagram of the roller pressing and bonding step in this invention. Detailed Implementation

[0032] Example 1

[0033] (1) Preparation of adhesive: Add 6g of PPC with a number average molecular weight of 20w to a 100ml brown glass bottle, seal it well, and bake it in a 50℃ oven for 12h; then inject 60ml of 99% pure anisole into the glass bottle, stir it on a 60℃ hot plate for 8h, and finally sonicate the solution at a frequency of 40khz for 3h for later use.

[0034] (2) Cut the large-area monolayer graphene and copper foil obtained by vapor deposition into 10cm×10cm for later use;

[0035] (3) A layer of graphene is grown on the copper foil and the adhesive is spin-coated at a speed of 1000 rpm. Then, it is placed on a 60°C hot plate and baked for 5 minutes. Then, the uncoated side of the copper foil is plasma-treated for 10 minutes at a power of 250W. Then, the copper foil / graphene coated side is rolled and laminated with the polymer adhesive layer side of the purchased transparent polymer composite film. The specific rolling and laminating steps are as follows: the uncoated side of the copper foil / graphene is used as the bottom surface, and a 175μm thick PET film is placed under it to prevent the graphene / copper foil from wrinkling and deforming during the rolling process. Then, one edge of the acrylate-containing side of the composite film is attached to the surface of the copper foil / graphene coated side, and the other side is fixed on a roller to make it taut, flat, and away from the copper foil surface. Then, the side of the composite film and the copper foil to be laminated is fed into the rolling press and slowly laminated at a speed of 0.1-3.5mm / s. If the composite film is long enough, it can be stretched around the roller; if it is not long enough, the front end of the composite film should be aligned and fixed on the roller, while ensuring that the non-acrylate, non-adhesive side of the composite film is in close contact with the roller to prevent wrinkles and deformation.

[0036] After rolling 3 to 5 sides, the resulting composite film with the graphene-free side facing down is placed in a 1 mol / L FeCl3 solution for etching until the metal substrate is completely removed.

[0037] The polymer substrate of the aforementioned transparent polymer composite film is composed of PET, with a thickness of 50 μm; the polymer adhesive layer is composed of acrylate, with a thickness of 50 μm.

[0038] (4) Cleaning and drying: After etching, the remaining composite film after removing the metal substrate is immersed in 4.0 mol / L hydrochloric acid for 15 min, then immersed and cleaned in deionized water four times, each time for 5 min, and finally the cleaned composite film is dried to obtain a single-layer graphene composite film material.

[0039] The resulting graphene composite film material has the following structure: PET / acrylate / PPC adhesive / graphene. Under conditions of 23°C and 50% RH, the water vapor transmission rate of the graphene composite film material was measured to be 2.5 × 10⁻⁶ using a GBPI W413 2.0 water vapor transmission rate tester, in accordance with GB / T 26253-2010. -2 g / (m 2 • 24hr); According to GB / T 2410-2008, using a Lambda 950 UV / Vis / IR spectrophotometer, the transmittance of the graphene composite film material was measured to be 87%.

[0040] Example 2

[0041] (1) Preparation of adhesive: Add 6g of PPC with a number average molecular weight of 20w to a 100ml brown glass bottle, seal it well, and bake it in a 50℃ oven for 12h; then inject 60ml of 99% pure anisole into the glass bottle, stir it on a 60℃ hot plate for 8h, and finally sonicate the solution at a frequency of 40khz for 3h for later use.

[0042] (2) Cut the large-area monolayer graphene and copper foil obtained by vapor deposition into 10cm×10cm for later use;

[0043] (3) A layer of graphene is grown on the copper foil and the adhesive is spin-coated at a speed of 1000 rpm. Then, it is placed on a 60°C hot plate and baked for 5 minutes. Then, the uncoated side of the copper foil is plasma-treated for 10 minutes at a power of 250W. Then, the coated side of the copper foil is rolled and bonded to the adhesive side of the purchased polymer composite film. That is, the uncoated side of the graphene / copper foil is used as the bottom surface, and a 175μm thick PET film is placed under it to prevent the graphene / copper foil from wrinkling and deforming during the rolling process. Then, one edge of the acrylate side of the composite film is attached to the coated surface of the copper foil / graphene, and the other side is fixed on a roller to make it taut, flat and away from the copper foil surface. Then, the composite film and the side of the copper foil / graphene are fed into the rolling press and slowly bonded at a speed of 0.1-3.5mm / s. If the composite film is long enough, it can be stretched around the roller; if it is not long enough, the front end of the composite film should be aligned and fixed on the roller, while ensuring that the non-acrylate, non-adhesive side of the composite film is in close contact with the roller to prevent wrinkles and deformation.

[0044] After rolling 3 to 5 sides, the resulting composite film with the graphene-free side facing down is placed in a 1 mol / L FeCl3 solution for etching until the metal substrate is completely removed.

[0045] (4) Cleaning and drying: After etching, the remaining composite film after removing the metal substrate is immersed in 4.0 mol / L hydrochloric acid for 15 min, then immersed and cleaned in deionized water four times, each time for 5 min, and finally the cleaned composite film is dried to obtain a single-layer graphene composite film material.

[0046] (5) Cut the large-area monolayer graphene and copper foil obtained by vapor deposition to a suitable size. The side without graphene is subjected to plasma treatment at a power of 250W for 10 minutes. Then, the side of the copper foil containing graphene is rolled and bonded to the side of the composite film containing graphene obtained in step (4) at 60°C. That is, the side of the graphene / copper foil without graphene is used as the bottom surface, and a 175μm thick PET film is placed under it to prevent the graphene / copper foil from wrinkling and deforming during the rolling process. Then, one edge of the composite film containing graphene is attached to the surface of the copper foil containing graphene, and the other edge is fixed on a roller to make it taut, flat, and away from the surface of the copper foil. Then, the side of the composite film and copper foil that is bonded is fed into the rolling press and slowly bonded at a speed of 0.1-3.5mm / s. If the composite film is long enough, it can be stretched around the roller; if it is not long enough, the front end of the composite film should be aligned and fixed on the roller, while the non-adhesive side of the composite film that is not bonded to graphene should be pressed against the roller to avoid wrinkles and deformation of the composite film.

[0047] Then, the composite film was statically pressed at 40°C for 12 hours using a glass plate. After static pressing, the composite film was etched in 1 mol / L FeCl3 until the metal substrate was completely removed. Finally, the etched composite film was cleaned and dried according to step (4) to obtain a double-layer graphene film composite material.

[0048] The resulting graphene composite film material has the following structure: PET / acrylate / PPC adhesive / graphene / graphene. Under conditions of 23°C and 50% RH, and according to GB / T 26253-2010, using a GBPI W4132.0 water vapor transmission rate tester, the water vapor transmission rate of the graphene composite film material was measured to be less than 1×10⁻⁶. -3 g / (m 2 • 24hr), exceeding the instrument's testing limit of 1×10 -3 g / (m 2 • 24hr); According to GB / T 2410-2008, using a Lambda 950 UV / Vis / IR spectrophotometer, the transmittance of the graphene composite film material was measured to be 85%.

[0049] Example 3

[0050] Other conditions were the same as in Example 2, except that the solute in the binder was replaced with PC polycarbonate. Under conditions of 23°C and 50% RH, the water vapor transmission rate of the graphene composite film material was measured to be 6.5 × 10⁻⁶ using a GBPI W413 2.0 water vapor transmission rate tester according to GB / T 26253-2010. -3 g / (m 2• 24hr); According to GB / T2410-2008, using a Lambda 950 UV / Vis / IR spectrophotometer, the transmittance of the graphene composite film material was measured to be 85%.

[0051] Example 4

[0052] Other conditions were the same as in Example 2, except that the area of ​​the copper foil and polymer composite film was changed to 20cm × 20cm, thus enlarging the sample. Under conditions of 23°C and 50% RH, the water vapor transmission rate of the graphene composite film material was measured to be less than 1 × 10⁻⁶ using a GBPI W4132.0 water vapor transmission rate tester according to GB / T 26253-2010. -3 g / (m 2 • 24hr), exceeding the instrument's testing limit of 1×10 -3 g / (m 2 • 24hr); According to GB / T 2410-2008, using a Lambda 950 UV / Vis / IR spectrophotometer, the transmittance of the graphene composite film material was measured to be 85%.

[0053] Comparative Example 1

[0054] (1) Cut the large-area monolayer graphene and copper foil obtained by vapor deposition into 10cm×10cm for later use;

[0055] (2) Apply a 250W plasma treatment to the graphene-free side of the copper foil for 10 minutes. Then, roll-press the graphene-containing side of the copper foil with the acrylic adhesive layer of the purchased PET / acrylate composite film. Specifically, place the graphene / copper foil without graphene as the bottom surface, and place a 175μm thick PET film underneath it to prevent wrinkles and deformation of the graphene / copper foil during the rolling process. Then, attach one side of the composite film with acrylic adhesive layer to the surface of the graphene-containing copper foil, and fix the other side to a roller to keep it taut, flat, and away from the copper foil surface. Then, feed the composite film and the copper foil side into the roll press and slowly laminate them at a speed of 0.1-3.5mm / s. If the composite film is long enough, it can be stretched around the roller; if it is not long enough, the front end of the composite film should be aligned and fixed on the roller, while ensuring that the acrylic adhesive-free side of the composite film is in close contact with the roller to prevent wrinkles and deformation of the composite film.

[0056] After repeating the rolling process as described above 3 to 5 times, place the resulting composite film with the graphene-free side facing down in a 1 mol / L FeCl3 solution to etch until the metal substrate is completely removed.

[0057] (3) Cleaning and drying: After etching, the remaining composite film after removing the metal substrate is immersed in 4.0 mol / L hydrochloric acid for 15 min, then immersed and cleaned in deionized water four times, each time for 5 min, and finally the cleaned composite film is dried to obtain a single-layer graphene composite film material.

[0058] (4) Cut the large-area monolayer graphene and copper foil obtained by atmospheric deposition to a suitable size. The side without graphene is treated with plasma at 250W for 10 minutes. Then, the graphene-containing side of the copper foil and the graphene-containing side of the composite film obtained in step (4) are rolled together at 60°C. That is, the graphene-free side of the graphene / copper foil is used as the bottom surface, and a 175μm thick PET film is placed under it to prevent the graphene / copper foil from wrinkling and deforming during the rolling process. Then, one side of the graphene-containing side of the composite film is attached to the graphene-containing surface of the copper foil, and the other side is fixed on a roller to make it taut, flat, and away from the copper foil surface. Then, the side of the composite film and the copper foil that are attached are fed into the rolling press and slowly attached at a speed of 0.1-3.5mm / s. If the composite film is long enough, it can be stretched around the roller; if it is not long enough, the front end of the composite film should be aligned and fixed on the roller, while the graphene-free and non-adhesive side of the composite film should be in close contact with the roller to avoid wrinkles and deformation of the composite film.

[0059] Next, the composite film is sandwiched between glass plates and statically pressed at 40°C for 12 hours. Then, the statically pressed composite film is placed in 1 mol / L FeCl3 to be etched until the metal substrate is completely removed. Finally, the etched composite film is cleaned and dried according to step (4) to obtain a double-layer graphene film composite material.

[0060] The resulting graphene composite film material has the structure of PET / acrylate / graphene / graphene, which, compared to Example 2, does not contain PPC as a binder. Under conditions of 23°C and 50% RH, the water vapor transmission rate of the graphene composite film material was measured to be 0.44 g / (m²) using a GBPI W413 2.0 water vapor transmission rate tester according to GB / T 26253-2010. 2 •24hr).

[0061] Comparative Example 2

[0062] (1) Preparation of adhesive: Add 6g of PPC with a number average molecular weight of 20w to a 100ml brown glass bottle, seal it well, and bake it in a 50℃ oven for 12h; then inject 60ml of 99% pure anisole into the glass bottle, stir it on a 60℃ hot plate for 8h, and finally sonicate the solution at a frequency of 40khz for 3h for later use.

[0063] (2) Cut the large-area monolayer graphene and copper foil obtained by vapor deposition into 10cm×10cm for later use;

[0064] (3) A layer of graphene was grown on the copper foil and the adhesive was spin-coated at a speed of 1000 rpm. Then, it was placed on a hot plate at 60°C and baked for 5 minutes. Then, the uncoated side of the copper foil was treated with plasma at a power of 250W for 10 minutes. Then, the coated side of the copper foil was directly bonded to the acrylic adhesive side of the purchased PET / acrylate composite film using a static press. The resulting composite film with the graphene-free side facing down was placed in a 1 mol / L FeCl3 solution for etching until the metal substrate was completely removed.

[0065] (4) Cleaning and drying: After etching, the remaining composite film after removing the metal substrate is immersed in 4.0 mol / L hydrochloric acid for 15 min, then immersed and cleaned in deionized water four times, each time for 5 min, and finally the cleaned composite film is dried to obtain a single-layer graphene composite film material.

[0066] (5) Cut the large-area monolayer graphene and copper foil obtained by vapor deposition to a suitable size. The side without graphene is treated with plasma at 250W for 10 minutes. Then, the side of the copper foil containing graphene is directly bonded to the side of the composite film containing graphene obtained in step (4) at 60°C using a static press. Next, the composite film is sandwiched between glass plates and statically pressed at 40°C for 12 hours. Then, the statically pressed composite film is placed in 1mol / L FeCl3 for etching until the metal substrate is completely removed. Finally, the etched composite film is cleaned and dried according to step (4) to obtain a double-layer graphene film composite material.

[0067] The resulting graphene composite film material has the following structure: PET / acrylate / PPC adhesive / graphene / graphene, with a different bonding method compared to Example 2. Under conditions of 23°C and 50% RH, the water vapor transmission rate of the graphene composite film material was measured to be 0.35 g / (m²) using a GBPI W413 2.0 water vapor transmission rate tester, in accordance with GB / T 26253-2010. 2 •24hr).

[0068] Comparative Example 3

[0069] Other experimental conditions were the same as in Example 2, except that the number-average molecular weight of PPC was 1w. Under conditions of 23°C and 50% RH, the water vapor transmission rate of the graphene composite film material was measured to be 4.1 × 10⁻⁶ using a GBPI W4132.0 water vapor transmission rate tester according to GB / T 26253-2010. -3 g / (m 2• 24hr); According to GB / T 2410-2008, using a Lambda 950 UV / Vis / IR spectrophotometer, the transmittance of the graphene composite film material was measured to be 85%.

[0070] Comparative Example 4

[0071] Other experimental conditions were the same as in Example 2, except that the number-average molecular weight of PPC was 40w. Under conditions of 23°C and 50% RH, the water vapor transmission rate of the graphene composite film material was measured to be 2.1 × 10⁻⁶ using a GBPI W413 2.0 water vapor transmission rate tester according to GB / T 26253-2010. -3 g / (m 2 • 24hr); According to GB / T 2410-2008, using a Lambda 950 UV / Vis / IR spectrophotometer, the transmittance of the graphene composite film material was measured to be 84%.

[0072] Table 1

[0073] <![CDATA[Water vapor permeability rate (g / (m 2 ·24hr))]]> Light transmittance (%) Example 1 <![CDATA[2.5×10 -2 g]]> 87 Example 2 <![CDATA[<1×10 -3 ]]> 85 Example 3 <![CDATA[6.5×10 -3 ]]> 85 Example 4 <![CDATA[<1×10 -3 ]]> 85 Comparative Example 1 0.44 / Comparative Example 2 0.35 / Comparative Example 3 <![CDATA[4.1×10 -3 ]]> 85 Comparative Example 4 <![CDATA[2.1×10 -3 ]]> 84

[0074] The water vapor permeation rate (WVTR) was tested using an infrared detector method, with the test standard being GB / T 26253-2010 and the equipment model being GBPI W413 2.0.

[0075] The test standard for light transmittance is GB / T 2410-2008, and the test instrument is a UV / Vis / IR spectrophotometer, model Lambda 950.

Claims

1. A graphene composite film material, characterized in that, The composite film material includes at least one layer of graphene on a transparent polymer composite film, the transparent polymer composite film being composed of a two-layer structure of a polymer substrate and a polymer adhesive layer; the polymer adhesive layer and the graphene layer of the transparent polymer composite film are connected by an adhesive. The solute in the adhesive is polypropylene carbonate, and the number average molecular weight of the solute is 5w-30w. The preparation method of the graphene composite film material includes the following steps: (1) Preparation of adhesive: The solute is placed in a brown glass bottle and sealed, and baked in an oven for 8 h-24 h; then the solvent is injected into the glass bottle, and the mass-to-volume ratio of the solute in g to the solvent in ml is 1:

10. Stir for 5-12 h, and finally the resulting solution is ultrasonically vibrated to obtain the adhesive. (2) Preparation of graphene layer: large-area monolayer graphene grown on metal substrate by vapor deposition; (3) Adhesion between graphene layer and polymer transparent film: The adhesive is coated on the side of the metal substrate where graphene is grown; after heating and curing, the side coated with the adhesive is rolled and bonded to the polymer adhesive layer side of the polymer transparent composite film; then the metal substrate is removed, and the remaining composite film is washed and dried to obtain a composite film material with a single layer of graphene.

2. The composite film material of claim 1, wherein, The preparation method of the graphene composite film material further includes: (4) The graphene-containing side of the composite film material with single-layer graphene obtained in step (3) is hot-rolled and pressed with the graphene-containing side of another metal substrate with graphene grown on it. Then the resulting composite film is heated and statically pressed for 12-48 hours. Finally, the metal substrate is removed, and the remaining composite film is washed and dried. Repeat this process multiple times to obtain a composite film material with multiple layers of graphene.

3. The composite film material of claim 2, wherein, The composite film material includes multiple layers of graphene on a transparent polymer composite film; adjacent graphene layers are directly connected without the aid of adhesives.

4. The composite film material of claim 3, wherein, The multilayer graphene is a bilayer graphene.

5. The composite film material of claim 1, wherein, The polymer substrate is composed of one or more of polyethylene terephthalate, polyethylene, cellulose triacetate, polyvinyl alcohol, polyvinyl chloride, and polyethylene naphthalate; and / or The polymer adhesive layer is composed of one or more of silicone resin, epoxy resin, polyacrylate, and ethylene-vinyl acetate copolymer.

6. The composite film material of claim 5, wherein, The thickness of the polymer substrate is 50-200 μm; and / or The thickness of the polymer adhesive layer is 1-100 μm.

7. The composite thin film material of claim 1, wherein, The single-layer graphene or the single-layer graphene constituting the multilayer graphene is a single-layer graphene grown on a metal substrate by vapor deposition; the metal substrate is one of Cu, Ni, Pt, Ru or an alloy thereof.

8. A method of making a composite film material, characterized by, The composite film material includes at least one layer of graphene on a transparent polymer composite film, the transparent polymer composite film being composed of a two-layer structure of a polymer substrate and a polymer adhesive layer; the polymer adhesive layer and the graphene layer of the transparent polymer composite film are connected by an adhesive. The solute in the adhesive is polypropylene carbonate, and the number average molecular weight of the solute is 5w-30w. The preparation method includes the following steps: (1) Preparation of adhesive: The solute is placed in a brown glass bottle and sealed, and baked in an oven for 8 h-24 h; then the solvent is injected into the glass bottle, and the mass-to-volume ratio of the solute in g to the solvent in ml is 1:

10. Stir for 5-12 h, and finally the resulting solution is ultrasonically vibrated to obtain the adhesive. (2) Preparation of graphene layer: large-area monolayer graphene grown on metal substrate by vapor deposition; (3) Adhesion between graphene layer and polymer transparent film: The adhesive is coated on the side of the metal substrate where graphene is grown; after heating and curing, the side coated with the adhesive is rolled and bonded to the polymer adhesive layer side of the polymer transparent composite film; then the metal substrate is removed, and the remaining composite film is washed and dried to obtain a composite film material with a single layer of graphene.

9. The preparation method according to claim 8, characterized in that, Also includes: (4) The graphene-containing side of the composite film material with single-layer graphene obtained in step (3) is hot-rolled and pressed with the graphene-containing side of another metal substrate with graphene grown on it. Then the resulting composite film is heated and statically pressed for 12-48 hours. Finally, the metal substrate is removed, and the remaining composite film is washed and dried. Repeat this process multiple times to obtain a composite film material with multiple layers of graphene.

10. The preparation method according to claim 9, characterized in that, The method for removing the metal substrate is an etching method, and the etching solution is a solution of one or more of the following: ferric chloride, sodium persulfate, ammonium persulfate, hydrogen peroxide, hydrochloric acid, or nitric acid; or The method for removing the metal substrate is an electrochemical bubbling method, using platinum or graphite as the anode, the metal substrate as the cathode, and the electrolyte being a solution of one or more of sodium hydroxide, potassium hydroxide, sodium nitrate, potassium nitrate, and ammonium nitrate.

11. The application of the composite thin film material according to any one of claims 1-7 or the composite thin film material prepared by the preparation method according to any one of claims 8-10 in the fields of OLED device encapsulation, pharmaceuticals, and food packaging.

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