KR20140098662A - Composition for encapsulating transparent thin film - Google Patents

Abstract

According to the present invention, provided is a transparent thin film encapsulating composition in which oxygen and water are efficiently blocked, and which improves the properties of service life and electricity when an organic electronic device is applied, by comprising 0.01-15 parts by weight of graphene , 1-50 parts by weight of polyimide or a precursor thereof, and 20-95 parts by weight of a solvent.

Description

TECHNICAL FIELD [0001] The present invention relates to a composition for transparent thin film encapsulation,

The present invention relates to a transparent thin film encapsulating composition having excellent oxygen and moisture barrier properties.

Through the upgrading of electronic devices, electronic devices based on organic materials have emerged. Representative organic electronic devices include organic light emitting devices (OLED) and organic photovoltaic (OPV). However, the organic materials used in these organic electronic devices are inevitably vulnerable to oxygen or air. When the organic material comes into contact with oxygen or air, a spontaneous oxidation reaction occurs, and as a result, the lifetime of the organic electronic device is significantly reduced. Accordingly, as a method for preventing oxidation of an organic material applied to the organic electronic device and ensuring a device lifetime characteristic at a commercially available level, there has been studied an encapsulation technique for blocking oxygen and moisture introduced from the outside. The water vapor transmission rate (WVTR) of 10 ^-3 to 10 ^-4 (g / m ² day) is required for an organic solar cell, for example. Moisture permeability of the organic light emitting diode is required to be 10 times or more higher than that of the organic light emitting diode. Compared to water moisture permeability of 10 ¹ to 10 ² for typical food packaging materials, oxygen or moisture permeability should be extremely low in organic electronic devices.

Conventionally, as a sealing technique in an organic electronic device, a method of sealing a organic device by applying a glass cap to an organic light emitting diode has been used. This has the problem that the sealing ability against moisture permeation is good but the thickness of the device is increased, the process is complicated, the manufacturing cost is high, it is vulnerable to external impact, and as a result, it is difficult to apply to a large area organic light emitting diode.

As a method to overcome this problem, the sealing technique of multilayer thin film structure has been developed. In the multilayer thin film structure encapsulation technique, an inorganic-inorganic multilayer thin film structure in which two or more inorganic layers each including a different kind of inorganic material such as SiN and SiO are laminated and an organic material such as an inorganic material such as Al ₂ O ₃ and a monomer, Organic multilayer thin film structure in which layers are alternately stacked using methods such as atomic layer deposition, MLD (Molecular layer deposition), or CVD (Chemical Vapor Deposition).

In the encapsulation technology using the inorganic-organic multilayer thin film structure, the role of blocking oxygen and moisture mainly takes place in the inorganic layer. However, when the thickness of the inorganic layer is reduced to a nanometer level, defects such as pinholes of 0.1 to 3 micrometers are generated. In order to delay the penetration time of oxygen and moisture, it is necessary to form an organic layer thicker or to form one layer each of an inorganic layer and an organic layer as one cycle, moisture caused by defects such as pinholes in the inorganic layer, Layer structure of at least five cycles or more than ten cycles in order to prevent oxygen penetration. In the case of the top emission organic light emitting diode, optical characteristics are also required for the encapsulating material due to the operating mechanism for viewing the image through light passing through the encapsulation layer. Therefore, when a multi-layer structure is formed by making the thicknesses of the inorganic layer and the organic layer different from each other to be different from each other, diffraction and interference phenomena of light may occur, which may hinder optical transparency and distort the wavelength of a specific color. This problem becomes more serious as the number of stacking cycles increases. In addition, since ALD for laminating the inorganic layer and CVD for depositing the organic layer must be repeatedly performed, the manufacturing process is complicated, the process time is long, and it is difficult to apply the large organic electronic device.

Korea Patent Publication No. 2011-0084110 (disclosed on July 21, 2011)

Disclosed is a transparent thin film encapsulating composition which is excellent in oxygen and moisture barrier properties.

The present invention also provides an encapsulant comprising an encapsulating layer made using the above-mentioned transparent thin-film encapsulating composition and an organic electronic device including the same.

The transparent thin film encapsulation composition according to one embodiment of the present invention comprises 0.01 to 15 parts by weight of graphene, 1 to 50 parts by weight of polyimide or precursor thereof, and 20 to 95 parts by weight of solvent.

In the transparent thin film encapsulation composition, the graphene may have a single-layer structure or a multi-layer structure of 2 to 10 layers.

The graphene may have a size of 0.1 to 30 mu m.

The graphene may have a carbon: oxygen fraction of 65:35 to 99: 1.

The polyimide may be prepared by imidizing a polyamic acid obtained by polymerizing dianhydride with a diamine compound and having an imidization rate of 50% or more.

The polyimide or precursor thereof may have a coefficient of thermal expansion (CTE) of 20 to 30 ppm / ° C.

The solvent may be selected from the group consisting of an amide-based solvent, a pyrrolidone-based solvent, and a mixture thereof.

The transparent thin film encapsulation composition may further comprise additives selected from the group consisting of wetting agents, dispersants, defoamers, and mixtures thereof.

Also, the transparent thin film encapsulation composition may be to the change in viscosity of the initial equation shear rate, calculated as 1 (1 ^-s) and end shear rate (100 ^-s) of from 1 to 3.

[Equation 1]

Viscosity change (X) = Initial shear rate (1 ^-s) viscosity at viscosity / final shear rate (100 ^-s) in

According to another embodiment of the present invention, there is provided an encapsulant comprising an encapsulating film prepared using the above-mentioned transparent thin film encapsulating composition.

The encapsulating material may further include an inorganic encapsulating film.

The sealing material may include an inorganic sealing film including a pinhole, and a sealing film formed on the inorganic sealing film using the above-mentioned transparent sealing film composition, wherein the pinhole of the inorganic sealing film comprises graphene .

Wherein the sealing material further comprises a sealing film of a multilayer structure in which an inorganic sealing film and an organic sealing film are alternately formed, and the sealing film produced using the transparent sealing film composition is located on the uppermost layer of the sealing film of the multi- And may be located on at least one of the inorganic encapsulating films existing in the encapsulating film.

According to another embodiment of the present invention, there is provided an organic electronic device including a sealing film manufactured using the above-mentioned transparent thin film encapsulating composition.

Other details of the embodiments of the present invention are included in the following detailed description.

The transparent thin film encapsulation composition according to the present invention can improve sealing performance against thermal changes of a device based on polyimide or its precursor having excellent thermal stability, chemical resistance and transparency, and can be used for various applications such as SiN, Al ₂ O ₃ And the inorganic sealing film of the present invention exhibits an excellent coating property through the interfacial action based on the surface tension and the contact angle with the inorganic sealing film of the inorganic sealing film, thereby forming a uniform sealing layer, and as a result, excellent oxygen and moisture blocking effect can be exhibited. Also, the graphene contained in the transparent thin-film encapsulating composition effectively blocks oxygen and moisture penetrating through the pinhole in the inorganic encapsulation layer, thereby further improving the encapsulation property, thereby improving the optical characteristics by reducing the thickness of the encapsulation material.

Accordingly, when applied to an organic electronic device, it exhibits excellent oxygen and moisture blocking effects, and can improve the lifetime characteristics and the electrical characteristics of the organic electronic device.

1 is a cross-sectional view schematically showing the structure of an encapsulant according to an embodiment of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS The present invention is capable of various modifications and various embodiments, and specific embodiments are illustrated in the drawings and described in detail in the description. It is to be understood, however, that the invention is not to be limited to the specific embodiments, but includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention. Also, the terms first, second, etc. may be used to describe various components, but the components should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from another.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The singular expressions include plural expressions unless the context clearly dictates otherwise.

As used herein, terms such as "comprises" or "having" are intended to specify that there is a stated feature, number, step, operation, element, component, or combination thereof, But do not preclude the presence or addition of features, numbers, steps, operations, components, parts, or combinations thereof.

Hereinafter, the transparent thin film encapsulation composition according to the present invention will be described in detail.

In general, polyimide resins have excellent thermal, mechanical stability, and chemical resistance, but are yellow due to their high aromatic ring density in the molecule, exhibit low light transmittance in the visible light range, and exhibit relatively high water permeability.

On the other hand, in the present invention, a transparent thin film encapsulation composition is prepared by mixing graphene based on transparent polyimide (CPI, Color-less polyimide) having excellent thermal stability, chemical resistance and transparency, The sealing performance is improved, the oxygen and moisture blocking effect is further improved, and the optical characteristic is improved.

That is, the transparent thin film encapsulation composition according to an embodiment of the present invention may include 0.01 to 15 parts by weight of graphene based on 100 parts by weight of the composition; 1 to 50 parts by weight of polyimide or a precursor thereof; And 20 to 95 parts by weight of a solvent.

In the transparent thin film encapsulation composition, graphene is formed by connecting a plurality of carbon atoms to each other through a covalent bond to form a polycyclic aromatic molecule. The graphene may have a single layer structure, or may have a multi-layer Structure. In general, graphene having a single-layer structure exhibits a light absorptivity of about 2%, and therefore, considering the light transmittance required for an encapsulant, the graphene may have a single-layer structure or a multilayer structure of two to ten layers May be desirable.

It is preferable that the graphene has a size of 0.1 to 30 탆, and it is more preferable that the graphene has a size of 0.1 to 5 탆 in order to effectively block the pinhole in the inorganic encapsulating film when it is applied to the encapsulating material including the inorganic encapsulating film .

In general, the larger the oxygen fraction in the graphene, the larger the hollow size in the graphene molecular structure. Therefore, it is preferable that the graphene has a carbon: oxygen ratio of 65:35 to 99: 1, considering the effect of blocking the oxygen and air of the graphene itself.

On the other hand, in the transparent thin film encapsulating composition, the polyimide and the precursor thereof can exhibit improved thermal stability, chemical resistance, and transparency, thereby exhibiting improved encapsulation performance as well as improved optical characteristics against thermal changes of the device. In addition, when an inorganic sealing film such as SiN or Al ₂ O _{3 is} used, excellent coating properties can be exhibited to the inorganic sealing film through the interfacial action based on the surface tension, the contact angle and the like.

Specifically, the polyimide or a precursor thereof is preferably 50% or more because it exhibits a sufficient curing effect, and more preferably 10 to 30%.

Since the polyimide or its precursor directly affects the transparency and optical characteristics of the sealing film formed by the transparent thin film encapsulating composition, when the coating or film is formed into a thickness of 50 탆, the yellow index (YI) 3 or less. When the YI value is more than 3, yellow appears, which may lower the transparency and optical characteristics of the sealing film.

The polyimide or its precursor itself has excellent thermal stability. However, the polyimide or its precursor has a thermal expansion coefficient (CTE) of 20 to 30 ppm / ° C. May be more preferable.

In the production of a transparent thin film using a polyimide, a precursor of a polyimide, for example, a polyamic acid-containing composition is coated and thermally cured to imidize the polyimide resin, Is dissolved and then coated and dried to produce a polyimide film, which is superior in the tightness and stiffness of film formation. Accordingly, it may be more preferable to use a polyimide precursor having a high imidization ratio as described above in the production of the transparent thin film encapsulating composition.

The polyimide or the precursor thereof may be prepared according to a conventional production method, or may be commercially available.

Specifically, the polyimide may be prepared by polymerizing a dianhydride with a diamine compound to prepare a polyamic acid, which is a precursor of the polyimide, and imidizing the polyamic acid.

As the dianhydride, 4,4 '- (hexafluoroisopropylidene) diphthalic anhydride (6FDA)), 4- (2,5-dioxo Tetrahydrofuran-3-yl) -1,2,3,4-tetrahydronaphthalene-1,2-dicarboxylic anhydride (4- (2,5-dioxotetrahydrofuran- , 3,4-tetrahydronaphthalene-1,2-dicarboxylic anhydride (TDA) or 4,4 '- (4,4'-isopropylidenepepoxy) bis (phthalic anhydride) 4,4'-isopropylidenediphenoxy) bis (phthalic anhydride, HBDA) may be used. Among them, 6FDA having excellent transparency to polyimide after curing may be more preferable.

Examples of the diamine compound include 2,2'-bis (trifluoromethyl) benzidine (TFB), 2,2'-bis (trifluoromethyl) -4, Bis (trifluoromethyl) -4,4'-diaminobiphenyl, TFDB), 1,4-bis (4-aminophenoxy) benzene ) benzene, 1,4 (4) -APB), 1,3-bis (4-aminophenoxy) benzene, 1,3 (4) 4-aminophenoxy) phenyl] sulfone, 4,4-BAPS (4APPS), 3,3'-hexafluoroisopropylidene dianiline (3,3'-hexafluoroisoporpylidenediamine, 3ADF), p-phenylene diamine (PDA) or 3,3'-thiobis [benzeneamine], DDSO2) Among them, TFB excellent in transparency improvement effect to polyimide after curing may be more preferable.

The polymerization reaction of the dianhydride with the diamine compound may be carried out in a solvent such as N, N-dimethylacetamide (DMAc) under a nitrogen stream.

The imidization reaction of the polyamic acid, which is a precursor of the polyimide produced as a result of the above polymerization reaction, can be carried out by a conventional method such as a thermal curing method or a chemical method using a catalyst.

In the production of the polyimide according to the above reaction, it is preferable to appropriately adjust the materials, the amount of use and the reaction conditions so as to satisfy the above-mentioned physical property requirements.

The polyimide or a precursor thereof is preferably included in an amount of 1 to 50 parts by weight based on 100 parts by weight of the transparent thin film encapsulating composition, so that it is possible to obtain moisture and gas blocking effect together with an appropriate adhesive force when applied on a substrate. If the content of the polyimide is more than 50 parts by weight, it is difficult to induce a close lamination between stacked and stacked graphene layers, so that the adhesive strength may be lowered. More preferably 1 to 10 parts by weight.

In the transparent thin film encapsulating composition, the solvent may be selected from the group consisting of an amide-based solvent, a pyrrolidone-based solvent, and a mixture thereof. Specific examples thereof include N-methylformamide (NMF), N, N-dimethylformamide (DMF), N, N-dimethylacetamide N-dimethylpropanamide (DMP), 3-butoxy-N, N-dimethyl-propaneamide (BDP), N-methylpiperazine N-methylpyrrolidone (NMP), 1,3-dimethyl-2-pyrrolidone (DMPy) and N-hexyl pyrrolidone (NHP) One or more mixed solvents selected from the group consisting of

The solvent is preferably included in an amount of 20 to 95 parts by weight based on 100 parts by weight of the composition. When it is included in the above content range, flowability suitable for the coating process of the composition such as spin coating, slit die coating, bar coating and the like can be obtained.

In addition, the transparent thin film encapsulating composition is preferably used in order to promote the π-π interaction of graphene and to improve the dispersibility of the graphene without worrying about the inherent properties of the graphene. In order to obtain sodium lauryl sulfate, sodium Wetting agents such as sodium monolaurin monosulfate, lauric acid monoester of diethylene glycol sulfoacetate sodium salt of diethylene glycol sulfoacetate sodium salt, or dodecyloxymethanesulfonate; A dispersing agent such as polyacrylic acid amine salt (PAAm) for increasing the dispersibility of the graphene powder in the transparent thin-film encapsulating composition; Or an antifoaming agent such as polydimethylsiloxane, may be further included in the transparent thin film encapsulation composition so as to enhance the effect of the transparent thin film encapsulation composition according to the present invention.

The additive may be used singly or in combination of two or more, and may be further contained in an effective amount capable of obtaining the effect of the additive without inhibiting the effect of the present invention.

Also, the transparent thin film encapsulation compositions to suitably adjusting the content of the above-mentioned constituents, the viscosity change in Equation initial shear rate, which is calculated as 1 (1 ^-s) and end shear rate (100 ^-s) 1 to 3 To improve the coating properties by imparting the back flushing property.

[Equation 1]

Viscosity change (X) = Initial shear rate (1 ^-s) viscosity at viscosity / final shear rate (100 ^-s) in

The transparent thin film encapsulation composition having such a constitution can be produced by mixing graphene, polyimide or a precursor thereof, and optionally additives into a solvent.

At this time, the mixing process can be performed by a conventional method such as ball milling.

In order to obtain the effect of improving dispersibility in the production of the transparent thin film encapsulating composition, a drying treatment or a wetting promotion treatment may be selectively performed as a pre-treatment for graphene, and both the steps may be sequentially carried out . Specifically, the drying step may be performed by heat treatment at 80 to 100 ° C for 10 minutes to 1 hour, and the wetting promotion treatment may be performed by treating the graphene powder with a wetting agent.

The transparent thin film encapsulation composition produced by the above-described production method can exhibit an excellent sealing effect against oxygen and moisture and improved sealing performance and optical characteristics against thermal change of the device. In addition, excellent coating properties are exhibited and a uniform thin film is possible. Accordingly, when applied to an organic electronic device, it exhibits excellent oxygen and moisture blocking effects, and can improve the lifetime characteristics and the electrical characteristics of the organic electronic device.

Accordingly, according to another embodiment of the present invention, there is provided an encapsulant comprising a sealing film manufactured using the transparent thin film encapsulating composition.

The encapsulating material may be formed by applying the above-mentioned transparent thin film encapsulating composition by a conventional method such as spray coating, die coating, spin coating, or inkjet printing, followed by drying by a conventional drying method such as hot air drying.

In addition, the encapsulation material may further include a transparent substrate for water and gas blocking together with support for the encapsulation film.

The transparent substrate is not particularly limited as long as it is a transparent substrate used in an organic electronic device. Specific examples of the transparent substrate include polyethylene terephthalate, polycarbonate, polyimide, polyethylene naphthalate and polyether sulfone.

Further, the sealing material may further include at least one of ordinary moisture and an oxygen-blocking inorganic sealing film and an organic sealing film. When the encapsulating material includes both the inorganic encapsulating film and the organic encapsulating film, the order of forming the inorganic encapsulating film and the organic encapsulating film is not particularly limited, and the inorganic encapsulating film and the organic encapsulating film may be alternately stacked and included.

In addition, the inorganic sealing film usually mineral is used as a sealing material in an organic electronic device, specifically, SiO, SiO _2, SiN _x, SiN _x O _y (wherein, 0 <x <1, 0 <y <1 Im Silicon oxide or nitride; Or a metal or metal oxide such as Al, Al ₂ O ₃ , or IZO (indium tin oxide).

The inorganic sealing film may have a single-layer structure in which the inorganic layer containing the inorganic substance is formed as one layer, or may have a multi-layer structure in which two or more inorganic layers each containing a different kind of inorganic substance are formed.

The inorganic encapsulating film may be formed according to a conventional thin film forming method. Specifically, the inorganic encapsulating film may be formed using ALD (Atomic layer deposition), MLD (Molecular layer deposition) or CVD (Chemical vapor deposition).

When the encapsulating material includes an inorganic encapsulating film, it is preferable that an encapsulating film produced by the composition for encapsulating a transparent thin film is formed on the inorganic encapsulating film.

In general, in the case of an inorganic sealing film, a pinhole is inevitably formed in a sealing film. However, when the transparent thin film encapsulating composition is applied onto the inorganic encapsulating film, the graphene contained in the transparent thin film encapsulating composition can penetrate into the pin hole in the inorganic encapsulating film. As a result, the penetration of oxygen and moisture by the pinhole is prevented .

In addition, the organic sealing film may include an organic substance used as an encapsulating material in an organic electronic device, specifically, an epoxy resin, an acrylate resin, a urethane acrylate, or a polyester.

The organic sealing film may have a single-layer structure or may have a multi-layer structure in which two or more organic layers each containing different kinds of organic materials are stacked.

The organic sealing film may also be formed according to a conventional thin film forming method.

In the case where the encapsulating material according to the present invention further comprises an inorganic encapsulating film or organic encapsulating film, the order of forming the encapsulating film, the inorganic encapsulating film and the organic encapsulating film to be produced by the composition for encapsulating a transparent film is not particularly limited, It is preferable that the sealing film formed by the transparent thin film sealing composition is formed on the inorganic sealing film in consideration of penetration of the pinhole in the sealing composition and consequent oxygen and moisture blocking effect.

For example, when the encapsulating material according to the present invention has a multilayer thin film structure of an inorganic encapsulating film-organic encapsulating film or an inorganic encapsulating film-inorganic encapsulating film, a sealing film formed by the transparent film encapsulation composition is formed on the uppermost layer of the multilayered film structure Or may be formed in a multilayer thin film structure. In this case, it is preferable to be formed on at least one inorganic encapsulating film among the inorganic encapsulating films forming the multilayered film structure.

1 is a cross-sectional view schematically showing an encapsulant having a multilayer thin film structure according to an embodiment of the present invention. FIG. 1 is an illustration for illustrating the present invention, but the present invention is not limited thereto.

1, an encapsulant 10 according to an embodiment of the present invention includes a transparent substrate 1 and a sealing film 5 formed by a transparent thin film encapsulating composition, and the transparent substrate 1 Layer film structure in which the organic encapsulating film 2 and the inorganic encapsulating film 3 are alternately formed between the transparent thin film 5 and the transparent thin film 5. Further, the multilayer thin film structure has a multilayer structure of two cycles, with one layer of the organic sealing film and one layer of the inorganic sealing film as one cycle (6).

The encapsulation material may exhibit excellent moisture and oxygen blocking effect by including an encapsulation film made using a composition for sealing a transparent thin film. Furthermore, when the encapsulating material comprises an inorganic encapsulating film and the encapsulating film produced by using the composition for encapsulating the transparent film is formed on the inorganic encapsulating film, the graphene contained in the transparent film encapsulating composition penetrates into the pinhole in the encapsulating film It is possible to prevent moisture and oxygen penetration by pinholes and to exhibit further improved sealing characteristics, thereby improving the optical characteristics while reducing the number of cycles of the laminated structure of the sealing material. As a result, it exhibits excellent oxygen and moisture blocking effect when applied to organic electronic devices, and can improve lifetime characteristics and electrical characteristics of organic electronic devices.

According to another embodiment of the present invention, there is provided an organic electronic device including an encapsulant manufactured using the transparent thin-film encapsulating composition.

The organic electronic device may be an organic light emitting diode (OLED), an organic photo voltaic (OPV), or the like.

Since the organic electronic device has the same structure as a conventional organic electronic device except that the sealing material is manufactured using the above-mentioned transparent thin-film encapsulating composition, a detailed description of the structure and the manufacturing method of the organic electronic device It is omitted.

Hereinafter, embodiments of the present invention will be described in detail so that those skilled in the art can easily carry out the present invention. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.

Example 1

The ingredients shown in Table 1 below were mixed in the stated amounts to prepare a transparent thin film encapsulation composition.

Specifically, 0.25 parts by weight of a graphene powder (C700 ™, manufactured by XG Science) dried in an oven at 80 ° C. for 1 hour was mixed with N, N-dimethylacetamide (DEA) and N-methylpyrrolidone (NMP) 4, and then 0.5 parts by weight of 3-amino-2-methylbenzyl alcohol (manufactured by Sigma-Aldrich) was added as a wetting agent. . To the resulting dispersion was added 0.5 part by weight of pyrene (manufactured by Sigma-Aldrich) as a dispersing agent, 0.5 part by weight of polyamic acid (4,4'- (hexafluoroisopropylidene) diphthalic anhydride (6FDA) 5 parts by weight of an imidization ratio of 90% and a thermal expansion coefficient of 25.9 ppm / 占 폚 at 200 占 폚 by polymerization reaction of bis (trifluoromethyl) benzidine (TFB) were added and ball milled for 12 hours A transparent thin film encapsulation composition was prepared.

Example 2

As shown in the following Table 1, in the same manner as in Example 1 except that 20 parts by weight of polyamic acid was used in Example 1 and the amount of solvent used was changed to 78.75 parts by weight, A composition was prepared.

 Example 3

As shown in the following Table 1, in the same manner as in Example 1 except that 50 parts by weight of polyamic acid was used in Example 1 and the amount of solvent used was changed to 48.75 parts by weight, A composition was prepared.

Example 4

As shown in the following Table 1, except that 5 parts by weight of polyimide resin (VTEC PI-1388 ™, USA) was used instead of polyamic acid in Example 1, a transparent thin film To prepare a sealing composition.

Comparative Example 1

Except that 5 parts by weight of bisphenol A epoxy resin (KER-3007 ™, manufactured by Kumho P & B) and hexamethylene diisocyanate (manufactured by Sigma Aldrich) were used as a curing agent in place of the polyamic acid in Example 1, Except that the amount of the solvent used was changed to 92.75 parts by weight, thereby preparing a transparent thin film encapsulating composition.

division ingredient Example 1 Example 2 Example 3 Example 4 Comparative Example 1 Filler Grapina
(C700 ™) 0.25 0.25 0.25 0.25 0.25 bookbinder Polyamic acid
(6FDA-PPA) 5 20 50 - - Bisphenol A epoxy resin
(KER-3007 ™) - - - - 5 Polyimide resin
(VTEC PI-1388 ™) - - - 5 Hardener Hexamethylene diisocyanate - - - One Solvent DEA / NMP (6: 4) mixed solvent 93.75 78.75 48.75 93.75 92.75 Wetting agent 3-Amino-2-methylbenzyl alcohol 0.5 0.5 0.5 0.5 0.5 Dispersant Pyrene 0.5 0.5 0.5 0.5 0.5 Total amount 100 100 100 100 100

In Table 1, the usage unit of each component is in parts by weight.

Further, in the embodiments 1 to 4 of a composition prepared in the initial shear rate (1 ^-s) and the final shear rate was calculated according to equation (1) above the change (X) The viscosity at (100 ^-s) from 1 to 3 &lt; / RTI &gt;

Test Example

The adhesiveness, transparency, density and sealing performance of the sealing compositions prepared in the above Examples and Comparative Examples were evaluated.

Specifically, the sealing compositions prepared in the above Examples and Comparative Examples were coated on a PES substrate by bar coating and then dried through hot air at 200 ° C to form a transparent thin film sealing film. The adhesiveness, transparency, density and sealing performance of the encapsulating film formed were evaluated in the following manner. The results are shown in Table 2.

1) Adhesiveness (100/100) was measured according to a cross-cut test (ASTM D3359). The larger the value, the better the adhesion.

2) The transmittance (T,%) was measured at 550 nm wavelength using visible infrared spectroscopy. The larger the transmittance value, the better the transmittance.

3) The density (%) is the ratio of the thickness immediately after coating and the thickness after curing of the composition containing the same amount of solid component, and the cross section of the sealing material was cut off and observed with an electron microscope. The lower the density value, the denser .

4) Yellowness index (YI * b) was measured according to ASTM D6290, and the lower Yellowness value means the more transparent.

5) The sealing performance (cm ³ m ^-2 day ^-1 , WVTR) was measured at room temperature using water and humidifier. The lower the value, the better the sealing performance.

Properties unit Way Example 1 Example 2 Example 3 Comparative Example 1 Adhesiveness 100/100 ASTM D3359 100/100 100/100 100/100 67/100 Transmittance T,% @ 550 85 83 80 83 Density - Dry thickness / coating thickness 0.025 0.1 0.25 0.075 Yellowness YI * b ASTM D6290 0.8 1.2 1.7 4 Encapsulation performance cm ³ m ^-2 day ^-1 WVTR 0.04 0.06 0.14 0.63

As shown in Table 2, the transparent thin film encapsulating compositions of Examples 1 to 3 according to the present invention showed better effects in terms of adhesiveness, transparency, density, transparency and encapsulation performance than Comparative Example 1.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, Of the right.

1: transparent substrate
2: organic sealing film
3:
4: Pinhole
5: sealing film
6: cycle
10: Encapsulation material

Claims (14)

0.01 to 15 parts by weight of graphene,
1 to 50 parts by weight of a polyimide or a precursor thereof, and
20 to 95 parts by weight of a solvent
/ RTI &gt; The method according to claim 1,
Wherein the graphene has a monolayer structure of one layer or a multi-layer structure of any one of two to ten layers. The method according to claim 1,
Wherein the graphene has a size of 0.1 to 30 占 퐉. The method according to claim 1,
Wherein the graphene has a carbon: oxygen fraction of 65:35 to 99: 1. The method according to claim 1,
Wherein the polyimide is prepared by imidizing a polyamic acid obtained by polymerizing dianhydride with a diamine compound and has an imidization rate of 50% or more. The method according to claim 1,
Wherein the polyimide or precursor thereof has a coefficient of thermal expansion (CTE) of 20 to 30 ppm / 占 폚. The method according to claim 1,
Wherein the solvent is selected from the group consisting of amide-based solvents, pyrrolidone-based solvents, and mixtures thereof. The method according to claim 1,
Wherein the composition further comprises an additive selected from the group consisting of wetting agents, dispersants, defoamers, and mixtures thereof. The method according to claim 1,
The composition Equation initial shear rate, calculated as 1 (1 ^-s) and end shear rate (100 ^-s), the viscosity change of from 1 to 3 of a transparent thin film encapsulation compositions.
[Equation 1]
Viscosity change (X) = Initial shear rate (1 ^-s) viscosity at viscosity / final shear rate (100 ^-s) in A sealing film made of a transparent thin film encapsulating composition comprising 0.01 to 15 parts by weight of graphene, 1 to 50 parts by weight of polyimide or a precursor thereof, and 20 to 95 parts by weight of a solvent. 11. The method of claim 10,
Wherein the sealing material further comprises an inorganic sealing film. 11. The method of claim 10,
Wherein the encapsulating material comprises an inorganic encapsulating film including a pinhole, and a sealing film disposed on the inorganic encapsulating film and made using the transparent film encapsulating composition,
Wherein the pinhole of the inorganic sealing film comprises graphene. 11. The method of claim 10,
Wherein the sealing material further comprises a sealing film of a multi-layer structure in which an inorganic sealing film and an organic sealing film are alternately formed,
Wherein the sealing film produced using the transparent thin film encapsulating composition is located on the uppermost layer of the sealing film of the multilayer structure or on the inorganic sealing film of at least one of the inorganic sealing films existing in the multilayered sealing film. 0.01 to 15 parts by weight of graphene, 1 to 50 parts by weight of a polyimide or a precursor thereof, and 20 to 95 parts by weight of a solvent.

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