KR20210110445A - Graphene composite barrier film and method for manufacturing the same - Google Patents

Abstract

The disclosed graphene composite barrier film comprises an inorganic thin film, an organic thin film disposed on the inorganic thin film, a graphene film, and a primer layer disposed between the organic thin film and the graphene film, wherein the graphene composite barrier film has water permeability less than or equal to 5 x 10^-5 g/m^2-day. According to the present invention, a barrier structure having highly improved moisture blocking force.

Description

Graphene composite barrier film and manufacturing method thereof

The present invention relates to a barrier film, and more particularly, to a graphene composite barrier film and a method for manufacturing the same.

With the development of science, the use of organic materials in materials such as solar cells and light emitting devices is increasing. These organic materials are rapidly decomposed when exposed to oxygen and moisture, and the lifespan of the device may be greatly reduced. In addition, in the case of food, it is made of organic matter, so it is vulnerable to moisture and other gases, and various blocking materials that can block moisture, oxygen, carbon dioxide, nitrogen, ultraviolet rays, etc. are applied as food packaging materials and are currently widely used. The demand for such blocking materials is increasing in various fields other than the field of electronics and food, as well as the field of chemistry.

Graphene has a two-dimensional carbon atomic plane structure in which a layer of carbon atoms is packed in a hexagonal lattice point plane. Graphene has 311 times stronger tensile strength than steel, 1,000 times faster electron mobility than silicon, 10 times better thermal conductivity than copper, transparent enough to pass 98% of light, and has properties even when bent or stretched. This property is maintained. Due to these characteristics, it can be widely used in nano materials, inks, barrier materials, heat dissipation materials, ultra-light materials, energy electrode materials, next-generation semiconductors, transparent electrodes, and the like.

Currently, studies have been conducted to improve the barrier performance against moisture by transferring graphene onto a plastic substrate. However, the result was poor performance due to the weak adhesion between graphene and the substrate.

1. Korea Patent Publication No. 10-2012-0069213 (2012.06.27.) 2. Korean Patent Publication No. 10-2013-0033783 (2013.03.28.) 3. Korean Patent Publication No. 10-2012-0082210 (2012.07.27.)

The technical problem of the present invention is to provide a graphene composite barrier film with improved moisture barrier properties and adhesion, which was conceived in this regard.

Another technical object of the present invention is to provide a method for manufacturing the graphene composite barrier film.

Graphene composite barrier film according to an embodiment for realizing the object of the present invention, an inorganic thin film, an organic thin film disposed on the inorganic thin film, a graphene film, and disposed between the organic thin film and the graphene film and a primer layer that is used, and has a water permeability of ^{5 x 10 -5} g/m ^{2 -day or less.}

In one embodiment, the inorganic thin film includes at least one selected from the group consisting of silicon oxide and silicon nitride.

In an embodiment, the organic thin film includes at least one selected from the group consisting of polyvinyl alcohol (PVA), polyvinyl butyral (PVD), and ethylene vinyl alcohol (EVOH).

In an embodiment, the organic thin film includes a polymer material and at least one selected from the group consisting of _{graphene flakes, graphene oxide flakes, and aluminum oxide (AL 2} O _{3 ) particles dispersed in the polymer material.}

In one embodiment, the primer layer includes at least one selected from the group consisting of a urethane resin and an epoxy resin.

A method for manufacturing a graphene composite barrier film according to embodiments of the present invention includes forming an inorganic thin film on a substrate, forming an organic thin film on the inorganic thin film, and comprising a urethane resin and an epoxy resin on the organic thin film Forming a primer layer comprising at least one selected from the group; and transferring the graphene film to the primer layer.

In one embodiment, the graphene composite barrier film has ^{a water permeability of 5 x 10 -5} g/m ² -day or less.

In one embodiment, the inorganic thin film includes at least one selected from the group consisting of silicon oxide and silicon nitride.

In an embodiment, the organic thin film includes at least one selected from the group consisting of polyvinyl alcohol (PVA), polyvinyl butyral (PVD), and ethylene vinyl alcohol (EVOH).

In an embodiment, the organic thin film includes a polymer material and at least one selected from the group consisting of _{graphene flakes, graphene oxide flakes, and aluminum oxide (AL 2} O _{3 ) particles dispersed in the polymer material.}

In one embodiment, the transferring of the graphene film to the primer layer includes: forming a graphene film on a catalyst substrate; forming a polymer protective film covering the graphene film; removing the catalyst substrate and adhering the exposed surface of the graphene film to the primer layer.

In an embodiment, the forming of the graphene film on the catalyst substrate includes: a first deposition step of forming a preliminary graphene film under a condition that a volume ratio of a process gas and a carbon precursor is 100:0.1 to 100:10; and a second deposition step of completing the graphene film under the condition that the volume ratio of the process gas and the carbon precursor is 100:10 to 100:50.

In an embodiment, the manufacturing method further comprises removing the polymer protective film after transferring the graphene film to the primer layer.

In an embodiment, the transferring of the graphene film to the primer layer includes forming a graphene film on a catalyst substrate, adhering the exposed surface of the graphene film to the primer layer, and the catalyst removing the substrate.

According to the present invention, it is possible to obtain a barrier structure with greatly improved moisture barrier properties. For example, the graphene composite barrier film may have a water vapor transmission rate (WVTR) of 5 x 10-5 g/m ² -day or less, which is a level usable as a barrier for an organic light emitting display device. . In addition, the graphene composite barrier film may have a high optical transmittance of 85% or more and a haze of 2% or less, and thus may have a high transmittance that can be used as a barrier of a display device.

1 to 9 are cross-sectional views illustrating a method of manufacturing a graphene composite barrier film according to embodiments of the present invention.
10 is a cross-sectional view illustrating a graphene composite barrier film according to an embodiment of the present invention.
11 is a graph showing the moisture permeability of the graphene composite barrier film according to Example 1 of the present invention.

In the present application, terms such as first and second may be used to describe various elements, but the elements should not be limited by the terms. The above terms are used only for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, a first component may be referred to as a second component, and similarly, a second component may also be referred to as a first component.

The terms used in the present application are only used to describe specific embodiments, and are not intended to limit the present invention. The singular expression includes the plural expression unless the context clearly dictates otherwise. In the present application, terms such as “comprise” or “have” are intended to designate that a feature, number, step, operation, component, part, or combination thereof described in the specification exists, but one or more other features It is to be understood that it does not preclude the possibility of the presence or addition of numbers, steps, operations, components, parts, or combinations thereof.

1 to 9 are cross-sectional views illustrating a method of manufacturing a graphene composite barrier film according to embodiments of the present invention.

Referring to FIG. 1 , an inorganic thin film 20 is formed on a base substrate 10 .

For example, the base substrate 10 is polyethylene terephthalate (Polyethyleneterephthalate, PET), polyethylene (Polyethylene, PE), polypropylene (Polypropylene, PP;), polycarbonate (Polycarbonate, PC), polymethyl methacrylate ( Polymethylmethacrylate, PMMA), polyimide (PI), oriented polypropylene (OPP), biaxially oriented polypropylene (BOPP), polyethylene 2,6-dicarboxyl naphthalate (Polyethylene 2,6) -dicarboxyl naphthalate, PEN), polyethersulfone (PES), polyester (Polyester), polystyrene (PS), or a combination thereof.

The inorganic thin film 20 may include silicon oxide, silicon nitride, silicon oxynitride, or a combination thereof. For example, the inorganic thin film 20 may be formed through sputtering, E-beam evaporation, thermal evaporation, pulsed laser deposition, or the like.

For example, the thickness of the inorganic thin film 20 may be 10 nm to 200 nm.

Referring to FIG. 2 , an organic thin film 30 is formed on the inorganic thin film 20 . The organic thin film may include a polymer material. For example, the organic thin film 30 may include polyvinyl alcohol (PVA), polyvinyl butyral (PVD), ethylene vinyl alcohol (EVOH), or a combination thereof. According to an embodiment, the organic thin film 30 may further include graphene flakes, graphene oxide flakes, aluminum oxide (AL ₂ O ₃ ) particles, etc. dispersed in a polymer material. In addition, the organic thin film 30 may include a composite of the polymer material and graphene.

For example, knife coating, roll coating, reverse roll coating, callender coating, curtain coating, cast coating, spray coating (Spray coating), Foam coating, Dip coating, air-knife coating, Extrusion coating, Inverted rod coating, Spin coating coating), a composition for forming an organic thin film may be coated on the inorganic thin film 20 and dried or cured to form the organic thin film 30 .

For example, the thickness of the organic thin film 30 may be 100 nm to 2 μm.

Referring to FIG. 3 , a primer layer 40 is formed on the organic thin film 30 . The primer layer 40 may include an epoxy resin, a urethane resin, or a combination thereof. In addition, the primer layer 40 may further include a polyfunctional monomer for curing, a photocuring initiator, and the like.

For example, knife coating, roll coating, reverse roll coating, callender coating, curtain coating, cast coating, spray coating (Spray coating), Foam coating, Dip coating, air-knife coating, Extrusion coating, Inverted rod coating, Spin coating coating), a composition for forming the primer layer 40 may be coated on the organic thin film 30 and dried or cured to form the primer layer 40 . For example, it can be coated by adjusting the speed of the knife, the rpm of the spin coating, etc. according to the viscosity of the composition.

When the primer layer 40 is formed, the viscosity may be adjusted using methyl ethyl ketone or toluene. When the viscosity of the composition for forming the primer layer 40 is excessively low, the adhesive force may be weakened.

For example, the thickness of the primer layer 40 may be 0.1 μm to 10 μm.

A graphene film may be coupled to the primer layer 40 . The graphene film may be formed by chemical vapor deposition or the like. After the graphene film is formed on the catalyst substrate, it may be transferred to the primer layer 40 .

4 to 7, in one embodiment of the present invention, shows the step of forming a graphene film and transferring it on the primer layer (40).

Referring to FIG. 4 , the graphene film 60 is formed on the catalyst substrate 50 .

For example, the catalyst substrate 50 may include nickel, palladium, platinum, copper, titanium, ruthenium, chromium, and iron. ), aluminum, silver, or a combination thereof.

For example, the thickness of the catalyst substrate 50 may be 100 nm to 40 μm. If the thickness is out of the above range, it may have a negative effect on etching during a subsequent transfer process, and may also affect a surface state according to a heat treatment process.

Before performing the chemical vapor deposition step for forming the graphene film 60, the catalyst to remove impurities on the surface of the catalyst substrate 50 and to adjust the roughness of the catalyst substrate 50 A pretreatment process such as annealing, electro-chemical polishing, and cleaning may be further performed on the substrate 50 . In this case, the graphene film may be more effectively formed, and properties related to gas and moisture barrier properties of the graphene-based barrier film may be further improved.

In an exemplary embodiment, when the annealing process is performed, the annealing process is different depending on the heat treatment time, but may be generally performed for about 30 minutes to 2 hours.

For example, the cleaning process may be performed using an etchant such as metal etchant, acetone, ethanol, methanol, isopropanol, or the like.

According to an embodiment, when the graphene film 60 is formed, defects of graphene can be minimized by increasing the domain size of graphene and reducing domain boundaries through a two-step growth method. For example, in the first deposition step, the minimum amount of carbon precursor flows and the maximum amount of inert gas flows to minimize nucleation to lower the density of each graphene domain, thereby increasing the domain size, and the second In the deposition step, by increasing the amount of the carbon precursor, the reduced growth rate can be increased again, and carbon atoms can be connected between each graphene domain.

For example, the first deposition step and the second deposition step may include low pressure chemical vapor deposition (LPCVD), atmospheric pressure chemical vapor deposition (APCVD), plasma enhanced chemical vapor deposition (PECVD), inductively coupled plasma chemical vapor deposition (ICP-) CVD), rapid heating chemical vapor deposition (RTCVD), metal organic chemical vapor deposition (MOCVD), or the like.

In the first deposition step and the second deposition step, a carbon precursor and a process gas may be provided.

For example, the process gas may include argon, nitrogen, hydrogen, ammonia, helium, or a combination thereof. For example, the mixed process gas may include a combination of argon/hydrogen, argon/nitrogen, argon/ammonia, argon/helium, and the like. The process gas affects the formation rate of the preliminary graphene film. When only hydrogen or nitrogen is used as the process gas, the preliminary graphene film may be formed more rapidly. However, in this case, it may cause a reverse reaction, so it is necessary to be careful depending on the process.

For example, the carbon precursor includes carbon monoxide, carbon dioxide, methane, ethane, ethylene, ethanol, acetylene, propane, butane, butadiene, pentane, pentene, cyclopentadiene, hexane, cyclohexane, benzene, toluene, or combinations thereof. can do.

In an embodiment, in the first deposition step, a volume ratio of the process gas and the carbon precursor may be 100:0.1 to 100:10. When the carbon precursor is included within the above range, nucleation of the preliminary graphene film may be minimized to lower the preliminary graphene domain density of the preliminary graphene film, thereby increasing the preliminary graphene domain size.

For example, the first deposition step may be performed under a temperature range of 600 to 1,100° C. and a pressure range of 100 mtorr to 760 mtorr, and the deposition step may be performed for 10 seconds to 10 minutes.

In an embodiment, in the second deposition step, a volume ratio of the process gas and the carbon precursor may be 100:10 to 100:50. By increasing the weight part of the carbon precursor in the second deposition step, the reduced growth rate can be increased again, and the graphene domains of the graphene film can be perfectly connected.

For example, the second deposition step may be performed under a temperature range of 600 to 1,100° C. and a pressure range of 100 mtorr to 760 mtorr, and the deposition step may be performed for 5 minutes to 1 hour.

Accordingly, the preliminary graphene film formed on the catalyst substrate 50 may be converted into a graphene film, thereby forming a graphene film having a dense structure.

Referring to FIG. 5 , a polymer protective film 70 is formed on the graphene film 60 . When the polymer protective film 70 is formed, the graphene film 60 can be easily transferred to a substrate to be transferred later, and the catalyst substrate 50 can be selectively etched later.

For example, the polymer protective film 70 includes polymethyl methacrylate, polydimethylsiloxane, polyvinyl alcohol, polyvinylpyrrolidone, or a combination thereof. can do.

For example, the polymer protective film 70 is formed through a process comprising coating a polymer material on the graphene film 60 to form a coating layer and baking the coating layer. can be The coating process may be performed through spin coating, spray coating, drop coating, bar coating, or dip coating.

The solvent of the polymer material may be removed through the baking process. For example, the baking process may be performed for 5 to 30 minutes under a temperature range of 50 to 150 ℃.

Although not shown, a graphene film may also be formed on the lower surface of the catalyst substrate 50 . (Hereinafter, this is referred to as a back graphene film). After the polymer protective film 70 is formed, the graphene film formed on the back surface of the catalyst substrate 50 may be removed through etching. This may be for easily removing the catalyst substrate 50 .

For example, as a method for etching the back side graphene film, reactive ion etching (Reactive Ion Etching. ICE), Inductively Coupled Plasma RIE (ICP-RIE), electron-cyclotron-resonance reactive ions Etching processes such as Electron Cyclotron Resonance RIE (ECR-RIE), Reactive Ion Beam Etching (RIBE), Chemical Assistant Ion Beam Etching (CABE), etc. are examples.

Referring to FIG. 6 , the catalyst substrate 50 is removed from the graphene film 60 .

For example, in the process of removing the catalyst substrate 50, an _{etching solution such as ammonium persulfate, iron chloride (FeCl 3} ), nitric acid, hydrochloric acid, sulfuric acid, etc. is used. It can be performed using

Accordingly, the catalyst substrate 50 may be removed to expose the graphene film 60 .

Referring to FIG. 7 , the graphene film 60 is attached to the primer layer 40 . The primer layer 40 has high adhesion to the graphene film 60 and the organic thin film 30 . Accordingly, a highly reliable composite barrier film including the graphene film 60 can be obtained.

In one embodiment, after attaching the graphene film 60 to the primer layer 40, a drying process may be performed to remove moisture.

In addition, after attaching the graphene film 60 to the primer layer 40 , the primer layer 40 may be cured to improve adhesion. For example, the primer layer 40 may be cured by UV or the like.

Referring to FIG. 8 , the polymer protective layer 70 may be removed. For example, the polymer protective layer 70 may be removed by immersing the composite barrier film in a solution such as acetone.

In another embodiment, the polymer protective film 70 may be a thermal release tape. When the polymer protective film 70 is a thermal release tape, when heated and pressurized to attach to the graphene film 60 and the primer layer 40 , the thermal release tape is easily peeled from the graphene film 60 . can be

In another embodiment, the polymer protective film 70 is not removed, but may be used as a configuration of a graphene composite barrier film.

In another embodiment, as shown in FIG. 9 , the graphene film 60 formed on the catalyst substrate 50 is directly transferred to the primer layer 40 without using the polymer protective film 70 . can For example, in order to increase the bonding strength of the primer layer 40 , after the graphene film 60 and the primer layer 40 are adhered, the primer layer 40 may be cured.

After the graphene film 60 and the primer layer 40 are combined, the catalyst substrate 50 may be removed.

10 is a cross-sectional view illustrating a graphene composite barrier film according to an embodiment of the present invention.

As shown in FIG. 10 , the graphene composite barrier film may include a plurality of graphene films. For example, the graphene composite barrier film may include an organic thin film 30 disposed on the inorganic thin film 20 , a first primer layer 40a disposed on the organic thin film 30 , and the first primer layer 40a ) combined with a first graphene film 60a, a second primer layer 40b disposed on the first graphene film 60a, and a second graphene film 60b disposed on the second primer layer 40b ) may be included.

The graphene composite barrier film of the above structure is, for example, as shown in FIG. 8 , after removing the polymer protective film 70 , a second primer layer 40b is formed, and the second primer layer 40b is It may be obtained by transferring the second graphene film 60b.

The graphene composite barrier film according to embodiments of the present invention may increase the bonding strength between the graphene film and the inorganic thin film/organic thin film by using a primer layer.

Accordingly, it is possible to obtain a barrier structure with greatly improved moisture barrier properties. For example, the graphene composite barrier film may have a water vapor transmission rate (WVTR) of 5 x 10-5 g/m ² -day or less, which is a level usable as a barrier for an organic light emitting display device. . In addition, the graphene composite barrier film may have a high optical transmittance of 85% or more and a haze of 2% or less, and thus may have a high transmittance that can be used as a barrier of a display device.

Hereinafter, specific examples of the present invention will be described in more detail through specific examples.

Example 1

Formation of inorganic thin film

An inorganic thin film having a thickness of 50 nm including silicon oxide or silicon nitride was formed on a PET substrate by sputtering.

Formation of organic thin film

An organic thin film including graphene and a polymer material was formed on the inorganic thin film. In the case of coating, bar number 16 was used, and curing was carried out at 110° C. for 5 minutes and at 135° C. for 1 minute. After curing, the thickness of the organic thin film was confirmed to be 500 nm.

formation of primer layer

Methyl ethyl ketone or toluene was added to the urethane-based adhesive composition, followed by stirring at 1,700 rpm for 20 hours, followed by coating.

In the case of using the blade coating equipment, the coating conditions were a temperature of 25° C. and a knife speed of 2.0 mm/sec to 5.0 mm/sec.

In the case of using spin coating equipment, the coating conditions were performed at 4,000 rpm for 60 seconds.

Formation of graphene film and removal of catalyst substrate

Graphene was grown on a copper substrate using chemical vapor deposition (CVD). The defects of graphene were minimized by increasing the domain size of graphene and reducing domain boundaries through a two-step growth method on a copper substrate. After the cleaned copper substrate was placed in a furnace, it was heated to 1,030° C. in an atmosphere of 100 sccm of hydrogen and a pressure of 340 mtorr, and then a heat treatment process was performed in this atmosphere for 50 minutes. After that, the mixed gas was flowed for 8 minutes in an atmosphere of methane 2 sccm, hydrogen 100 sccm, and a pressure of 365 mtorr. . Then, it was rapidly cooled to room temperature in an atmosphere of hydrogen 15 sccm and a pressure of 72 mtorr.

Next, in order to transfer the prepared graphene, PMMA was spin-coated on the graphene prepared on the copper substrate at 4,000 rpm for 50 seconds. The PMMA-coated graphene film was baked at 120° C. for 3 minutes. Next, to remove the graphene on the back side, the graphene on the back side was removed with O ₂ plasma through reactive-ion etching. Next, in order to remove the copper substrate, it was placed in a 0.1 M ammonium persulfate solution for 4 hours to remove the copper substrate. The ammonium persulfate solution remaining on the graphene film was removed through tertiary distilled water.

transfer of graphene film

The graphene was pressed onto the primer layer and dried at 60° C. for 10 minutes to remove the remaining moisture.

11 is a graph showing the moisture permeability of the graphene composite barrier film according to Example 1 of the present invention. Referring to Figure 11, the graphene composite barrier film, after stabilization (after about 70 hours), close to 0, specifically, 5 x 10 ^-5 g / m ² -day It can be seen that it has a water permeability of less than can

Although the above has been described with reference to the embodiments, those skilled in the art can variously modify and change the present invention within the scope without departing from the spirit and scope of the present invention described in the claims below You will understand.

The present invention may be used as a food packaging material, a back sheet barrier film of a solar cell, a barrier film of a display device, a vacuum insulating material envelope, and the like.

Claims (14)

inorganic thin film;
an organic thin film disposed on the inorganic thin film;
graphene film; and
A graphene composite barrier film comprising a primer layer disposed between the organic thin film and the graphene film, and having a water permeability of ^{5 x 10 -5} g/m ^{2 -day or less.} The graphene composite barrier film according to claim 1, wherein the inorganic thin film comprises at least one selected from the group consisting of silicon oxide and silicon nitride. The graphene composite barrier film according to claim 1, wherein the organic thin film comprises at least one selected from the group consisting of polyvinyl alcohol (PVA), polyvinyl butyral (PVD) and ethylene vinyl alcohol (EVOH). . According to claim 1, wherein the organic thin film comprises a polymer material and at least one selected from the group consisting of _{graphene flakes, graphene oxide flakes, and aluminum oxide (AL 2} O _{3 ) particles dispersed in the polymer material.} Graphene composite barrier film. The graphene composite barrier film according to claim 1, wherein the primer layer comprises at least one selected from the group consisting of a urethane resin and an epoxy resin. forming an inorganic thin film on a substrate;
forming an organic thin film on the inorganic thin film;
forming a primer layer including at least one selected from the group consisting of a urethane resin and an epoxy resin on the organic thin film; and
Method for producing a graphene composite barrier film comprising the step of transferring the graphene film to the primer layer. The method of claim 6, wherein the graphene composite barrier film has ^{a water permeability of 5 x 10 -5} g/m ² -day or less. The method of claim 6, wherein the inorganic thin film comprises at least one selected from the group consisting of silicon oxide and silicon nitride. The graphene composite barrier film according to claim 6, wherein the organic thin film comprises at least one selected from the group consisting of polyvinyl alcohol (PVA), polyvinyl butyral (PVD) and ethylene vinyl alcohol (EVOH). manufacturing method. The method of claim 6, wherein the organic thin film comprises a polymer material and at least one selected from the group consisting of _{graphene flakes, graphene oxide flakes, and aluminum oxide (AL 2} O _{3 ) particles dispersed in the polymer material.} A method for producing a graphene composite barrier film. The method of claim 6, wherein the transferring of the graphene film to the primer layer comprises:
forming a graphene film on the catalyst substrate;
forming a polymer protective film covering the graphene film;
removing the catalyst substrate; and
Method for producing a graphene composite barrier film comprising the step of adhering the exposed surface of the graphene film to the primer layer. The method of claim 11 , wherein the forming of the graphene film on the catalyst substrate comprises:
A first deposition step of forming a preliminary graphene film under the condition that the volume ratio of the process gas and the carbon precursor is 100:0.1 to 100:10; and
A method for producing a graphene composite barrier film, comprising: a second deposition step of completing the graphene film under the condition that the volume ratio of the process gas and the carbon precursor is 100:10 to 100:50. The method of claim 11 , further comprising removing the polymer protective film after transferring the graphene film to the primer layer. The method of claim 6, wherein the transferring of the graphene film to the primer layer comprises:
forming a graphene film on the catalyst substrate;
adhering the exposed surface of the graphene film to the primer layer; and
Method for producing a graphene composite barrier film comprising the step of removing the catalyst substrate.

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