Coating film comprising first coating layer and second coating layer, and display device comprising same

Abstract

An embodiment of the present invention provides: a coating film comprising a base film, a first coating layer which is on the base film, a second coating layer which is on the first coating layer, and interlayer bonding polymers which are disposed across the first coating layer and the second coating layer; a method for manufacturing the coating film; and a display device comprising the coating film.

Description

Coating film comprising a first coating layer and a second coating layer and a display device comprising the same

[0001] The present invention relates to a coating film including a first coating layer and a second coating layer, a method for manufacturing the coating film, and a display device including the coating film.

[0002] Light-transmitting films are a key material in the optical and flexible display fields, and their importance is growing. Light-transmitting films are being used as a replacement for glass in the display field, particularly due to their light weight, ease of processability, and flexibility. Conventional light-transmitting films are known to have lower mechanical properties than glass, such as low surface hardness and low abrasion resistance. Research is being conducted to improve the mechanical properties of light-transmitting films for their application in the display field.

[0003] One method for improving the mechanical or optical properties of a light-transmitting film is to place a coating layer on the surface of the light-transmitting film. A light-transmitting film with a coating layer placed thereon is also called a coated film.

[0004] One embodiment of the present invention is to provide a coating film including a coating layer having excellent adhesive properties.

[0005] One embodiment of the present invention provides a coating film including a first coating layer and a second coating layer, and having excellent adhesion between the first coating layer and the second coating layer.

[0006] One embodiment of the present invention seeks to provide a coating film having excellent hardness, excellent wear resistance, and excellent adhesiveness.

[0007] Another embodiment of the present invention provides a method for manufacturing a coating film.

[0008] Another embodiment of the present invention is to provide a display device including a coating film.

[0009] One embodiment of the present invention for solving the above problem provides a coating film having one or more grid pattern peelability, including a base film, a first coating layer on the base film, a second coating layer on the first coating layer, and an interlayer bonding polymer disposed across the first coating layer and the second coating layer.

[0010] One end of the interlayer bonding polymer may be positioned in the first coating layer, and the other end of the interlayer bonding polymer may be positioned in the second coating layer.

[0011] The above interlayer bonding polymer can be formed by polymerization of a photopolymerizable monomer.

[0012] The above interlayer bonding polymer includes an acrylic polymer.

[0013] The second coating layer may include an acrylic polymer resin.

[0014] The first coating layer may include a siloxane resin.

[0015] The first coating layer may be formed by a first coating composition including an epoxy-based siloxane binder and an acrylic-based siloxane binder.

[0016] The above epoxy-based siloxane binder may include an epoxy-based siloxane monomer, and the above acrylic-based siloxane binder may include an acrylic-based siloxane monomer.

[0017] The above epoxy siloxane monomer can be polymerized by heat treatment, and the above acrylic siloxane monomer can be polymerized by light irradiation.

[0018] The above siloxane resin may include an epoxy-based siloxane resin and an acrylic-based siloxane resin.

[0019] The above epoxy siloxane resin includes an epoxy siloxane repeating unit, the above acrylic siloxane resin includes an acrylic siloxane repeating unit, and the number of the epoxy siloxane repeating units may be greater than the number of the acrylic siloxane repeating units.

[0020] The above first coating layer may include the acrylic siloxane monomer.

[0021] The above second coating layer can be formed by photopolymerization of an acrylic composition.

[0022] The interlayer bonding polymer can be formed by photopolymerization of the acrylic siloxane monomer included in the first coating composition and the acrylic composition for forming the second coating layer.

[0023] The above-mentioned base film and the first coating layer may have a refractive index difference in the range of 0.1 to 0.3, and the first coating layer and the second coating layer may have a refractive index difference of less than 0.1.

[0024] The above coating film can have a light transmittance of 90% or more.

[0025] The second coating layer may have a pencil hardness of 5H or more.

[0026] Another embodiment of the present invention provides a method for producing a coating film, comprising the steps of: applying a first coating composition on a base film; applying heat to the first coating composition to form a first coating layer; applying a second coating composition on the first coating layer; and forming a second coating layer by irradiating the second coating composition with light, wherein the first coating composition comprises an epoxy-based siloxane monomer and an acrylic siloxane monomer, and the second coating composition comprises an acrylic monomer. Here, the content of the epoxy-based siloxane monomer is in a range of 30 to 70 wt%, and the content of the acrylic siloxane monomer is in a range of 30 to 70 wt%, based on the total weight of the monomers included in the first coating composition.

[0027] The above epoxy siloxane binder may include an epoxy siloxane monomer, and the acrylic siloxane binder may include an acrylic siloxane monomer. In the step of forming the second coating layer, the acrylic siloxane monomer included in the first coating layer and the acrylic monomer included in the second coating composition may be polymerized by the light irradiation, so that an interlayer bonding polymer may be formed across the first coating layer and the second coating layer.

[0028] The epoxy siloxane monomer may be polymerized by the heat applied to the first coating composition. The acrylic siloxane monomer may not be polymerized by the heat applied to the first coating composition.

[0029] The acrylic siloxane binder included in the first coating layer and the acrylic monomer included in the second coating composition can be polymerized by light irradiated to the second coating composition.

[0030] In the step of forming the second coating layer, the acrylic siloxane binder included in the first coating layer and the acrylic monomer included in the second coating composition may be polymerized to form an interlayer bonding polymer across the first coating layer and the second coating layer.

[0031] The interlayer bonding polymer can be formed across the interface between the first coating layer and the second coating layer, in the first coating layer and the second coating layer.

[0032] Another embodiment of the present invention provides a display device including a display panel and the above-described coating film disposed on the display panel.

[0033] A coating film according to one embodiment of the present invention can have excellent adhesiveness because it includes an interlayer bonding polymer disposed across the first coating layer and the second coating layer.

[0034] A coating film according to one embodiment of the present invention has excellent adhesive stability and can have excellent wear resistance and excellent hardness.

[0035] According to one embodiment of the present invention, by controlling the composition and curing conditions of the first coating layer and the second coating layer during the manufacturing process of the coating film, an interlayer bonding polymer disposed across the first coating layer and the second coating layer can be formed.

[0036] A coating film according to one embodiment of the present invention can be attached to a display surface of a display device and used. A display device including the coating film can have excellent hardness, surface wear resistance, and coating stability.

[0037] FIG. 1 is a schematic cross-sectional view of a coating film according to one embodiment of the present invention.

[0038] Figure 2 is a schematic diagram illustrating a process for producing an interlayer bonding polymer according to one embodiment of the present invention.

[0039] Figures 3a and 3b are schematic diagrams of the structure of an interlayer bonding polymer according to one embodiment of the present invention, respectively.

[0040] Figure 4 is a schematic diagram illustrating a process for producing an interlayer bonding polymer according to another embodiment of the present invention.

[0041] Figures 5a and 5b are schematic diagrams of the structure of an interlayer bonding polymer according to another embodiment of the present invention, respectively.

[0042] Figures 6a to 6c are schematic cross-sectional views of a manufacturing process of a coating film according to one embodiment of the present invention.

[0043] FIG. 7 is a cross-sectional view of a portion of a display device according to one embodiment of the present invention.

[0044] Figure 8 is an enlarged cross-sectional view of portion “P” of Figure 7.

[0045] Figure 9 is a schematic cross-sectional diagram illustrating the grid pattern formation process for measuring grid pattern peelability.

[0046] The present invention will be described in detail below, focusing on examples. The examples described below are provided for illustrative purposes only to facilitate a clear understanding of the present invention and do not limit its scope.

[0047] In this specification, where "includes," "has," and "consists of" are used, other parts may be added, unless the expression "only" is used. When a component is expressed in the singular, the plural is included unless otherwise explicitly stated. Furthermore, when interpreting a component, it is interpreted to include a margin of error, even if there is no explicit indication otherwise.

[0048] When describing a positional relationship, for example, when the positional relationship between two parts is described as 'on top of', 'upper part of', 'lower part of', 'next to', etc., one or more other parts may be located between the two parts, unless the expression 'right' or 'directly' is used.

[0049] When describing a temporal relationship, for example, when the temporal relationship is described as 'after', 'following', 'next to', 'before', etc., it can also include cases where it is not continuous, as long as the expression 'immediately' or 'directly' is not used.

[0050] While terms like "first" and "second" are used to describe various components, these components are not limited by these terms. These terms are used merely to distinguish one component from another. Therefore, a "first" component referred to below may also be a "second" component within the technical scope of the present invention.

[0051] The term "at least one" should be understood to include all possible combinations of one or more associated items. For example, "at least one of the first, second, and third items" can mean any combination of items that can be represented by two or more of the first, second, and third items, as well as each of the first, second, and third items.

[0052] The features of each of the various embodiments of the present invention can be partially or wholly combined or combined with each other, and various technical connections and operations are possible, and each embodiment can be implemented independently of each other or implemented together in a related relationship.

[0053] Figure 1 is a schematic cross-sectional view of a coating film (100) according to one embodiment of the present invention.

[0054] Referring to FIG. 1, a coating film (100) according to one embodiment of the present invention includes a base film (110), a first coating layer (120) on the base film (110), and a second coating layer (130) on the first coating layer (120).

[0055] A light-transmitting film can be used as the substrate film (110). A polyimide-based (PI) film can be used as the light-transmitting film. Examples of the polyimide-based (PI) film include a polyimide film and a polyamide-imide film.

[0056] A polyimide-based film according to one embodiment of the present invention can be manufactured from monomer components including dianhydride and diamine. More specifically, a polyimide-based film according to another embodiment of the present invention can have imide repeating units formed by dianhydride and diamine.

[0057] Additionally, polyimide-based films can also be manufactured from monomer components that further include a dicarbonyl compound in addition to dianhydride and diamine. Accordingly, a polyimide-based film according to one embodiment of the present invention may have imide repeating units and amide repeating units. An example of a polyimide-based film having imide repeating units and amide repeating units is a polyamide-imide film.

[0058] However, one embodiment of the present invention is not limited thereto, and a polycarbonate film (PC), a polyacrylic film, a polyethylene terephthalate film, a cellulose film, or the like may be used as the base film (110).

[0059] According to one embodiment of the present invention, there is no particular limitation on the thickness of the substrate film (110). The substrate film (110) may have a thickness sufficient to allow the coating film (100) to protect the display panel. For example, the substrate film (110) may have a thickness of 10 to 100 μm.

[0060] According to one embodiment of the present invention, a first coating layer (120) is disposed on a substrate film (110).

[0061] The first coating layer (120) acts as an interface layer between the two layers. The first coating layer (120) has excellent adhesion to the base film (110) and also has excellent adhesion to the second coating layer (130). The first coating layer (120) can act as an interface layer between the base film (110) and the second coating layer (130). Therefore, the first coating layer (120) can be referred to as an interface layer or an adhesion promoting layer, or can also be referred to as a primer layer.

[0062] The first coating layer (120) can serve to improve the adhesive strength between the base film (110) and the second coating layer (130). The second coating layer (130) can be stably attached to the base film (110) through the first coating layer (120).

[0063] In order to ensure that the second coating layer (130) can be stably attached to the substrate film (110), the first coating layer (120) may have a thickness of 0.05 to 1.0 ㎛.

[0064] When the thickness of the first coating layer (120) is less than 0.05 ㎛, it may be difficult to stably attach the second coating layer (130) to the base film (110). As a result, the adhesive strength and adhesion between the base film (110) and the second coating layer (130) may be reduced.

[0065] On the other hand, if the thickness of the first coating layer (120) exceeds 1.0 ㎛, the thickness of the coating film (100) may become thicker than necessary, and the flexibility, foldability, and flexible properties of the coating film (100) may deteriorate, and the optical properties may also deteriorate.

[0066] According to one embodiment of the present invention, the first coating layer (120) may include a siloxane resin. More specifically, the first coating layer (120) may be formed using a first coating composition including a siloxane binder.

[0067] For example, the first coating layer (120) may be formed by a first coating composition including an epoxy-based siloxane binder and an acrylic-based siloxane binder. The epoxy-based siloxane binder may include an epoxy-based siloxane monomer, and the acrylic-based siloxane binder may include an acrylic-based siloxane monomer.

[0068] According to one embodiment of the present invention, the first coating composition including an epoxy-based siloxane binder can be polymerized or cured by thermal polymerization. Therefore, according to one embodiment of the present invention, the first coating layer (120) can be formed by thermal polymerization of the first coating composition.

[0069] As an epoxy siloxane monomer, for example, 3-glycidoxypropyl trimethoxysilane can be used. An example of 3-glycidoxypropyl trimethoxysilane is KBM-403 from ShinEtsu.

[0070] However, one embodiment of the present invention is not limited thereto, and other known epoxy siloxane monomers may be used. Examples of the epoxy siloxane monomer include 2-(3,4 epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, and the like.

[0071] As an acrylic siloxane monomer, for example, 3-methacryloxypropyl trimethoxysilane can be used. According to one embodiment of the present invention, 3-methacryloxypropyl trimethoxysilane can be used. As 3-methacryloxypropyl trimethoxysilane, for example, there is KBM-503 from ShinEtsu.

[0072] However, one embodiment of the present invention is not limited thereto, and other known acrylic siloxane monomers may also be used. Examples of acrylic siloxane monomers include 3-acryloxypropyl trimethoxysilane, 3-methacryloxypropyl methyldimethoxysilane, and the like.

[0073] According to one embodiment of the present invention, in the first coating composition for forming the first coating layer (120), the content of the epoxy-based siloxane monomer may be more or less than the content of the acrylic siloxane monomer. The content of the epoxy-based siloxane monomer may be 30 to 70 wt% and the content of the acrylic siloxane monomer may be 30 to 70 wt% with respect to the total weight of the monomers included in the first coating composition. Specifically, the content of the epoxy-based siloxane monomer may be 40 to 60 wt% and the content of the acrylic siloxane monomer may be 40 to 60 wt% with respect to the total weight of the monomers included in the first coating composition, and more specifically, the content of the epoxy-based siloxane monomer may be 45 to 55 wt% and the content of the acrylic siloxane monomer may be 45 to 55 wt%.

[0074] However, one embodiment of the present invention is not limited thereto, and the content of the epoxy-based siloxane monomer may be 40 to 60 mol%, and the content of the acrylic siloxane monomer may be 40 to 60 mol%, with respect to the total mole number of monomers included in the first coating composition.

[0075] According to one embodiment of the present invention, the epoxy siloxane monomer can be polymerized by heat treatment, and the acrylic siloxane monomer can be polymerized by light irradiation.

[0076] Additionally, according to one embodiment of the present invention, the siloxane resin of the first coating layer (120) may include an epoxy-based siloxane resin and an acrylic-based siloxane resin. The epoxy-based siloxane resin may include an epoxy-based siloxane repeating unit, and the acrylic-based siloxane resin may include an acrylic-based siloxane repeating unit.

[0077] The first coating layer (120) may include an acrylic siloxane monomer. The acrylic siloxane monomer included in the first coating layer (120) corresponds to an unreacted acrylic monomer.

[0078] According to one embodiment of the present invention, a second coating layer (130) is disposed on the first coating layer (120). According to one embodiment of the present invention, the second coating layer (130) may include an acrylic polymer resin.

[0079] The second coating layer (130) can be formed by a second coating composition. The second coating composition can include a polymerizable monomer.

[0080] According to one embodiment of the present invention, the second coating composition may include an acrylic monomer. The acrylic monomer is a polymerizable monomer. A second coating composition including an acrylic monomer may be referred to as an acrylic composition.

[0081] The second coating composition containing an acrylic monomer can be cured by photopolymerization. Therefore, according to one embodiment of the present invention, the second coating layer (130) can be formed by photopolymerization of the acrylic composition, which is the second coating composition.

[0082] According to one embodiment of the present invention, dipentaerythritol hexaacrylate (DPHA) may be used as an acrylic monomer for forming the second coating layer (130).

[0083] However, one embodiment of the present invention is not limited thereto, and other known acrylic monomers may be used as monomers for forming the second coating layer (130). Examples of acrylic monomers include pentaerythritol triacrylate (PETA), hexanediol diacrylate (HDDA), etc.

[0084] According to one embodiment of the present invention, the second coating composition may further include, in addition to the acrylic monomer, a silane compound and a polymerization curing aid. The polymerization curing aid may include a diol and water (H2O).

[0085] According to one embodiment of the present invention, a siloxane may be formed by a silane compound. Specifically, the coating composition may be polymerized and cured by polymerization and curing of the silane compound, thereby forming a second coating layer (130).

[0086] A coating composition according to one embodiment of the present invention may further include one or more additives selected from the group consisting of a polymerization initiator, an antioxidant, a leveling agent, and a coating agent.

[0087] According to one embodiment of the present invention, as a polymerization initiator, for example, a photopolymerization initiator such as an organometallic salt and a thermal polymerization initiator such as an amine or imidazole can be used. The polymerization initiator can be used in an amount of about 0.01 to 2 parts by weight per 100 parts by weight of the polymerizable monomer.

[0088] According to one embodiment, an organic solvent may be used to form the second coating layer (130). The viscosity of the coating composition can be controlled by the organic solvent, and accordingly, the processability of the coating composition can be controlled, so that the thickness of the second coating layer (130) can be easily adjusted.

[0089] As an organic solvent, at least one selected from the group consisting of ketones such as acetone, methyl ethyl ketone, methyl butyl ketone, and cyclohexanone; cellosolves such as methyl cellosolve and butyl cellosolve; ethers such as ethyl ether and dioxane; alcohols such as isobutyl alcohol, isopropyl alcohol, butanol, and methanol; halogenated hydrocarbons such as dichloromethane, chloroform, and trichloroethylene; and hydrocarbons such as normal hexane, benzene, and toluene may be used.

[0090] According to one embodiment of the present invention, a second coating layer (130) can be formed by polymerization and curing of the second coating composition.

[0091] For example, a second coating composition may be pre-polymerized to form a paste-like pre-polymer, an organic solvent may be added to the pre-polymer to produce a paste-like second coating composition with adjusted viscosity, and then the second coating composition may be coated on a first coating layer (120) on a base film (110), followed by curing and polymerization to form a second coating layer (130).

[0092] More specifically, when the second coating composition is coated on the first coating layer (120), the first coating layer (120) includes a polymer polymerized by an epoxy siloxane monomer and may include an acrylic siloxane monomer.

[0093] According to one embodiment of the present invention, the second coating composition according to one embodiment of the present invention may be coated on the first coating layer (120) by a method such as coating, casting, or molding, and then photopolymerized to form the second coating layer (130).

[0094] When the second coating composition is polymerized, the light intensity conditions suitable for photopolymerization are 50 mJ / cm2 or more and 20,000 mJ / cm2 or less. To obtain a uniform surface before light irradiation, heat treatment may be performed at a temperature of 40°C or more and about 200°C or less.

[0095] For example, a second coating composition is coated on the first coating layer (120) on the substrate film (110), dried at 80°C for 5 minutes, and then UV_A is applied at 120 mW / cm 2 , 2J / cm 2 The second coating composition can be subjected to photocuring by irradiating it with a condition.

[0096] A coating film (100) according to one embodiment of the present invention includes an interlayer bonding polymer (140) disposed across a first coating layer (120) and a second coating layer (130).

[0097] One end of the interlayer bonding polymer (140) may be positioned on the first coating layer (120), and the other end of the interlayer bonding polymer (140) may be positioned on the second coating layer (130). For example, the interlayer bonding polymer (140) may be positioned on the first coating layer (120) and the second coating layer (130) across the interface between the first coating layer (120) and the second coating layer (130).

[0098] In FIG. 1, an interlayer bonding polymer (140) disposed across the interface between the first coating layer (120) and the second coating layer (130) is exemplarily illustrated.

[0099] FIG. 2 is a schematic diagram illustrating a process for producing an interlayer bonding polymer (140) according to one embodiment of the present invention.

[0100] Referring to FIG. 2, the interlayer bonding polymer (140) can be formed by polymerization of a photopolymerizable monomer. Specifically, the interlayer bonding polymer (140) can be formed by light irradiation. According to one embodiment of the present invention, when the second coating composition is coated on the first coating layer (120), the epoxy-based siloxane monomer of the first coating layer (120) is in a polymerized state, and the acrylic-based siloxane monomer is in a non-polymerized state.

[0101] According to one embodiment of the present invention, the acrylic siloxane monomer included in the first coating composition for forming the first coating layer (120) corresponds to a photopolymerizable monomer. In addition, the acrylic monomer for forming the second coating layer (130) corresponds to a photopolymerizable monomer.

[0102] Specifically, the monomer included in the first coating layer (120) in FIG. 2 may be an acrylic siloxane monomer. In FIG. 2, R1 may be a hydrocarbon group including a siloxane group.

[0103] Additionally, the monomer included in the second coating layer (130) in FIG. 2 may be an acrylic monomer. In FIG. 2, R2 may be a substituted or unsubstituted hydrocarbon group.

[0104] According to one embodiment of the present invention, an interlayer bonding polymer (140) can be formed by photopolymerization of an acrylic siloxane monomer included in a first coating composition for forming a first coating layer (120) and an acrylic monomer for forming a second coating layer (130).

[0105] The interlayer bonding polymer (140) may include, for example, an acrylic polymer. The interlayer bonding polymer (140) may include an acrylic repeating unit formed by an acrylic siloxane monomer and a repeating unit formed by an acrylic monomer.

[0106] According to one embodiment of the present invention, an acrylic repeating unit formed by an acrylic siloxane monomer in the first coating layer (120) and a repeating unit formed by an acrylic monomer in the second coating layer (130) can be connected to form an interlayer bonding polymer (140) (see FIG. 2).

[0107] More specifically, the interlayer bonding polymer (140) can be formed by photopolymerization of an acrylic siloxane binder included in a first coating composition for forming a first coating layer (120) and an acrylic composition for forming a second coating layer (130).

[0108] FIG. 3A illustrates an interlayer bonding polymer (140) formed by the process of producing the interlayer bonding polymer (140) illustrated in FIG. 2. In FIG. 3A, R1 may be a hydrocarbon group including a siloxane group, R2 may be a substituted or unsubstituted hydrocarbon group, and R3 may be hydrogen, a hydrocarbon group, a polymerization reaction group, a radical group, or a substituted hydrocarbon group. In FIG. 3A, “n” is a natural number.

[0109] Fig. 3b illustrates another embodiment of the interlayer bonding polymer (140). The interlayer bonding polymer (140) illustrated in Fig. 3b is an acrylate. In Fig. 3b, R 11 may be a hydrocarbon group containing a siloxane group, and R 21 may be a substituted or unsubstituted hydrocarbon group, and R 31 may be hydrogen, a hydrocarbon group, a polymerization reaction group, a radical group, or a substituted hydrocarbon group. In Fig. 3b, "m" is a natural number.

[0110] Fig. 4 is a schematic diagram illustrating a process for producing an interlayer bonded polymer according to another embodiment of the present invention. Figs. 5a and 5b are schematic diagrams of the structure of an interlayer bonded polymer according to another embodiment of the present invention, respectively.

[0111] In Figures 4 and 5a, R12 may be a hydrocarbon group containing a siloxane group, and R 22 may be a substituted or unsubstituted hydrocarbon group, and R 32 may be hydrogen, a hydrocarbon group, a polymerization reaction group, a radical group, or a substituted hydrocarbon group. In addition, R4 and R5 may each be hydrogen or a hydrocarbon group. In Fig. 5a, "p" is a natural number.

[0112] In Figure 5b, R1 may be a hydrocarbon group containing a siloxane group, and R 23 may be a substituted or unsubstituted hydrocarbon group, and R 33 may be hydrogen, a hydrocarbon group, a polymerization reaction group, a radical group, or a substituted hydrocarbon group. In addition, R 41 Wow R 51 Each can be a hydrogen or hydrocarbon group. In Fig. 5b, “q” is a natural number.

[0113] Referring to FIGS. 2, 3a, 3b, 4, 5a, and 5b, it can be seen that one end of the interlayer bonding polymer (140) is positioned on the first coating layer (120), and the other end of the interlayer bonding polymer (140) is positioned on the second coating layer (130). The interlayer bonding polymer (140) allows the first coating layer (120) and the second coating layer (130) to have excellent adhesion, adhesiveness, and adhesive stability. In addition, since the first coating layer (120) and the second coating layer (130) have excellent adhesion, adhesiveness, and adhesive stability, the optical film (100) can have excellent hardness.

[0114] According to one embodiment of the present invention, the second coating layer (130) can have excellent hardness, light transmittance, wear resistance, and scratch resistance. As a result, the coating film (100) including the second coating layer (130) can have excellent hardness, light transmittance, wear resistance, and scratch resistance.

[0115] According to one embodiment of the present invention, the second coating layer (130) may have a thickness of 2 to 10 μm. When the thickness of the second coating layer (130) is less than 2 μm, the hardness, wear resistance, and scratch resistance of the coating film (100) by the second coating layer (130) may not be sufficiently exhibited. When the thickness of the second coating layer (130) exceeds 10 μm, the thickness of the coating film (100) may become thicker, and the flexibility of the coating film (100) may be reduced.

[0116] According to one embodiment of the present invention, the base film (110) and the first coating layer (120) have a refractive index difference in the range of 0.1 to 0.3. In addition, the first coating layer (120) and the second coating layer (130) have a refractive index difference of less than 0.1. The first coating layer (120) may have a refractive index similar to that of the second coating layer (130). In addition, according to one embodiment of the present invention, the base film (110) and the second coating layer (130) may have a refractive index difference in the range of 0.1 to 0.3. As the refractive index difference between the base film (110) and the second coating layer (130) is adjusted to the range of 0.1 to 0.3, the coating film (100) may have excellent light transmittance.

[0117] According to one embodiment of the present invention, it is not easy to adjust the refractive index of the base film (110) and the second coating layer (130) to 0.1 or less due to the difference between the material constituting the base film (110) and the material constituting the second coating layer (130). Meanwhile, since the difference in refractive index between the base film (110) and the second coating layer (130) is adjusted to 0.3 or less, excessive reflection does not occur between the base film (110) and the second coating layer (130). As a result, the coating film (100) can have excellent light transmittance.

[0118] The substrate film (110) may have a refractive index of, for example, 1.6 to 1.7, and the second coating layer (130) may have a refractive index of 1.4 to 1.55. Additionally, the first coating layer (120) may have a refractive index of 1.4 to 1.53.

[0119] According to one embodiment of the present invention, the coating film (100) can have a light transmittance of 90% or more.

[0120] Light transmittance can be measured in the wavelength range of 360 to 740 nm by a spectrophotometer according to the standard specification JIS K 7361. As a spectrophotometer, for example, Hazemeter HM-150 / MURAKAMI COLOR RESEARCH LABORATORY can be used.

[0121] According to one embodiment of the present invention, the second coating layer (130) has a pencil hardness of 4H or more. As a result, it can be said that the coating film (100) has a pencil hardness of 4H or more.

[0122] Pencil hardness can be measured using a pencil hardness tester from IMOTO, Japan, at a speed of 180 mm / min and a load of 750 gf according to the measurement conditions of ASTM D3363.

[0123] According to one embodiment of the present invention, a coating film (100) has a grid pattern peelability of one or less. The grid pattern peelability is a value obtained by measuring the number of grid patterns of the second coating layer (130) that are separated from the coating film (100) and attached to the tape when 100 grid patterns (10 x 10) of 1 mm x 1 mm are formed on the second coating layer (130) of the coating film (100) using a cutter knife, 3M Scotch Box Tape (48 mm, transparent) (#3650) is attached to the surface of the second coating layer, and the tape is detached within 0.1 second.

[0124] When forming a grid pattern on the second coating layer (130) using a cutter knife, only the second coating layer (130) is cut, and the substrate film (110) is not cut. Since the first coating layer (120) has a thin thickness, it may or may not be partially cut.

[0125] The grid pattern can be formed, for example, by the method illustrated in FIG. 9.

[0126] Figure 9 is a schematic cross-sectional view illustrating the process of forming a grid pattern (130p) for measuring grid pattern peelability.

[0127] Referring to Fig. 9, a grid pattern (130p) can be formed by cutting or slicing from the surface of the second coating layer (130) to the first coating layer (120) based on the thickness direction of the coating film (100). In the process of forming the grid pattern (130p), the second coating layer (130) can be cut or cut by a cutter knife (K).

[0128] A cutting groove (130s) is formed by cutting with a cutter knife (K). The cutting groove (130s) penetrates the second coating layer (130) and may partially penetrate the first coating layer (120). Each grid pattern (130p) may be defined by the cutting groove (130s).

[0129] In the coating film (100) according to one embodiment of the present invention, since the second coating layer (130) has excellent adhesion to the first coating layer (120), the second coating layer (130) is not easily separated from the first coating layer (120). Therefore, the coating film (100) according to one embodiment of the present invention can have one or less grid pattern peelability.

[0130] In addition, the coating film (100) according to one embodiment of the present invention may have a grid pattern peelability of one or less after heat treatment at 230°C for one hour. Specifically, even if the grid pattern peelability of the coating film (100) according to one embodiment of the present invention is measured after heat treatment at 230°C for one hour, the coating film (100) according to one embodiment of the present invention may have a grid pattern peelability of one or less.

[0131] The coating film (100) according to one embodiment of the present invention may have a yellowness index of 3.0 or less. More specifically, the coating film (100) according to one embodiment of the present invention may have a yellowness index of 2.5 or less. In addition, the coating film (100) according to one embodiment of the present invention may have a yellowness index of 3.0 or less after heat treatment at 230°C for 1 hour, and more specifically, may have a yellowness index of 2.5 or less.

[0132] Another embodiment of the present invention provides a method for manufacturing a coating film (100).

[0133] Figures 6a to 6c are schematic cross-sectional views of a manufacturing process of a coating film (100) according to one embodiment of the present invention. Hereinafter, with reference to Figures 6a to 6c, another embodiment of the present invention will be described in detail regarding a method for manufacturing a coating film (100).

[0134] Another embodiment of the present invention is a method for manufacturing a coating film (100), which includes a step of applying a first coating composition (121) on a base film (110), a step of applying heat (HEAT) to the first coating composition (121) to form a first coating layer (120), a step of applying a second coating composition (131) on the first coating layer (120), and a step of irradiating light (LIGHT) to the second coating composition (131) to form a second coating layer (130).

[0135] Referring to FIG. 6a, a first coating composition (121) is applied on a substrate film (110).

[0136] A light-transmitting film can be used as the substrate film (110). A polyimide-based (PI) film can be used as the light-transmitting film. Examples of the polyimide-based (PI) film include a polyimide film and a polyamide-imide film.

[0137] The first coating composition (121) may include an epoxy-based siloxane binder and an acrylic siloxane binder.

[0138] According to one embodiment of the present invention, the epoxy-based siloxane binder may include an epoxy-based siloxane monomer. Additionally, the acrylic-based siloxane binder may include an acrylic-based siloxane monomer. On a molar basis, the content of the epoxy-based siloxane monomer may be greater than the content of the acrylic-based siloxane monomer.

[0139] Next, heat (HEAT) is applied to the first coating composition (121). Applying heat (HEAT) to the first coating composition (121) is also called heat treatment.

[0140] Referring to Fig. 6a, a first coating layer (120) is formed on a substrate film (110). The first coating layer (120) is formed by heat (HEAT) applied to the first coating composition (121).

[0141] Specifically, the epoxy siloxane monomer is polymerized by heat (HEAT) applied to the first coating composition (121). As a result, an epoxy siloxane polymer is formed in the first coating layer (120).

[0142] The first coating composition (121) contains an acrylic siloxane monomer in addition to an epoxy siloxane monomer. However, the acrylic siloxane monomer is not polymerized by heat (HEAT) applied to the first coating composition (121).

[0143] Even after undergoing heat treatment according to Fig. 6a, an acrylic siloxane monomer, which is an acrylic siloxane binder, remains in the first coating layer (120).

[0144] Referring to FIG. 6b, a second coating composition (131) is applied onto the first coating layer (120). The second coating composition (131) contains an acrylic monomer. When the second coating composition is applied onto the first coating layer (120), the epoxy siloxane monomer contained in the first coating composition (121) is in a polymerized state, and most of the acrylic siloxane monomer is in an unpolymerized state.

[0145] Next, light is irradiated onto the second coating composition (131). As a result, a second coating layer (130) is formed as shown in Fig. 6c.

[0146] The acrylic monomer included in the second coating composition (131) is polymerized by light (LIGHT) irradiated onto the second coating composition (131). As a result, an acrylic polymer (135) is formed. The acrylic polymer (135) is formed on the second coating layer (130).

[0147] In addition, the acrylic siloxane binder included in the first coating layer (120) is polymerized by light (LIGHT) irradiated on the second coating composition (131). Specifically, the acrylic siloxane monomer included in the acrylic siloxane binder is polymerized by light (LIGHT). As a result, an acrylic siloxane polymer can also be formed in the first coating layer (120), and in the process, an interlayer bonding polymer (140) is formed (see FIGS. 2 and 4).

[0148] According to one embodiment of the present invention, in the step of forming the second coating layer (130), the acrylic siloxane binder included in the first coating layer (120), which is a primer layer, and the acrylic monomer included in the second coating composition (131) are polymerized to form an interlayer bonding polymer (140) across the first coating layer (120) and the second coating layer (130).

[0149] The interlayer bonding polymer (140) is formed across the interface between the first coating layer (120) and the second coating layer (130) and in the first coating layer (120) and the second coating layer (130).

[0150] The interlayer bonding polymer (140) may include an acrylic repeating unit formed by an acrylic siloxane monomer included in the first coating composition (121) and a repeating unit formed by an acrylic monomer included in the coating composition (131).

[0151] FIG. 7 is a cross-sectional view of a portion of a display device (200) according to another embodiment of the present invention, and FIG. 8 is an enlarged cross-sectional view of a portion “P” of FIG. 7.

[0152] Referring to FIG. 7, a display device (200) according to another embodiment of the present invention includes a display panel (501) and a coating film (100) on the display panel (501). FIG. 7 discloses a display device (200) including the coating film (100) of FIG. 1.

[0153] Referring to FIGS. 7 and 8, the display panel (501) includes a substrate (510), a thin film transistor (TFT) on the substrate (510), and an organic light-emitting element (570) connected to the thin film transistor (TFT). The organic light-emitting element (570) includes a first electrode (571), an organic light-emitting layer (572) on the first electrode (571), and a second electrode (573) on the organic light-emitting layer (572). The display device (200) disclosed in FIGS. 7 and 8 is an organic light-emitting display device.

[0154] The substrate (510) may be made of plastic. Specifically, the substrate (510) may be made of a polyimide-based resin or a polyimide-based film.

[0155] Although not shown, a buffer layer may be disposed on the substrate (510).

[0156] A thin film transistor (TFT) is disposed on a substrate (510). The thin film transistor (TFT) includes a semiconductor layer (520), a gate electrode (530) that is insulated from the semiconductor layer (520) and overlaps at least a portion of the semiconductor layer (520), a source electrode (541) connected to the semiconductor layer (520), and a drain electrode (542) that is spaced apart from the source electrode (541) and connected to the semiconductor layer (520).

[0157] Referring to Fig. 8, a gate insulating film (535) is disposed between a gate electrode (530) and a semiconductor layer (520). An interlayer insulating film (551) may be disposed on the gate electrode (530), and a source electrode (541) and a drain electrode (542) may be disposed on the interlayer insulating film (551).

[0158] A planarization film (552) is placed on a thin film transistor (TFT) to planarize the upper portion of the thin film transistor (TFT).

[0159] A first electrode (571) of an organic light-emitting element (570) is placed on a planarization film (552). The first electrode (571) is connected to a drain electrode (542) of a thin film transistor (TFT) through a contact hole provided in the planarization film (552). The first electrode (571) may also be connected to a source electrode (541).

[0160] The bank layer (580) is arranged on the first electrode (571) and the planarization film (552) to define a pixel area or a light-emitting area. For example, the bank layer (580) may be arranged in a matrix structure in a boundary area between a plurality of pixels, thereby defining a pixel area by the bank layer (580).

[0161] The organic light-emitting layer (572) is disposed on the first electrode (571). The organic light-emitting layer (572) may also be disposed on the bank layer (580). The organic light-emitting layer (572) may include one light-emitting layer, or may include two or more light-emitting layers stacked one above the other. The organic light-emitting layer (572) may emit light having any one of red, green, and blue colors, and may also emit white light.

[0162] The second electrode (573) is placed on the organic light-emitting layer (572).

[0163] A first electrode (571), an organic light-emitting layer (572), and a second electrode (573) can be laminated to form an organic light-emitting element (570).

[0164] Although not shown, when the organic light-emitting layer (572) emits white light, each pixel may include a color filter for filtering the white light emitted from the organic light-emitting layer (572) by wavelength. The color filter is formed on the path of light.

[0165] A thin film encapsulation layer (590) may be disposed on the second electrode (573). The thin film encapsulation layer (590) may include at least one organic film and at least one inorganic film, and at least one organic film and at least one inorganic film may be disposed alternately.

[0166] A coating film (100) is placed on a display panel (501) having the laminated structure described above. The coating film (100) can be used as a cover window that covers and protects the light-emitting surface of the display panel (501).

[0167] Hereinafter, the present invention will be described in more detail through specific examples and comparative examples. These examples and comparative examples are intended solely to illustrate the present invention more specifically and are not intended to limit the present invention.

[0168] <Example 1>

[0169] (1) Formation of the first coating layer (120)

[0170] 100 mmol (23.63 g) of 3-glycidoxypropyl trimethoxysilane (KBM-403, ShinEtsu), an epoxy siloxane monomer, 150 mmol (2.7 g) of distilled water, and 0.1 g of NaOH were mixed in a 50 mL flask and stirred at 60°C for 4 hours to prepare an epoxy siloxane binder. The mixing and stirring were performed in an open system.

[0171] 100 mmol (24.84 g) of 3-methacryloxypropyl trimethoxysilane (KBM-503, ShinEtsu), an acrylic siloxane monomer, 150 mmol (2.7 g) of distilled water, and 0.1 g of NaOH were mixed in a 50 mL flask and stirred at 60°C for 4 hours to prepare an acrylic siloxane binder. The mixing and stirring were performed in an open system.

[0172] 1.5 g of the above-prepared epoxy siloxane binder (3-glycidoxypropyl trimethoxysilane; 1.341 g), 1.5 g of the acrylic siloxane binder (3-methacryloxypropyl trimethoxysilane; 1.348 g), 97 g of MEK, and 0.03 g of 2-Ethyl-4-methylimidazole were mixed and stirred in a flask to prepare a first coating composition.

[0173] A 50㎛ thick polyimide film (CPI®, KOLON) was prepared as a substrate film (110).

[0174] The first coating composition manufactured above was applied to a base film (110) using Mayer Bar. No. 8, dried at 80°C for 2 minutes, and then heat-treated (thermal polymerization and thermal curing) at 120°C for 5 minutes to manufacture a first coating layer (120). In the process of forming the first coating layer (120), 3-glycidoxypropyl trimethoxysilane, which is an epoxy-based siloxane monomer contained in the first coating composition, is polymerized, and 3-methacryloxypropyl trimethoxysilane, which is an acrylic siloxane monomer, is not polymerized.

[0175] (2) Formation of the second coating layer (130)

[0176] Dipentaerythritol hexaacrylate (DPHA) was used as an acrylic monomer for forming the second coating layer (130).

[0177] Specifically, a coating composition was prepared by dissolving 3 g of DPHA and 0.15 g of 2,2-dimethoxy-2-phenylacetophenone in 6 g of MEK.

[0178] After applying the coating composition manufactured above using Mayer Bar no. 16 on the formed first coating layer (120), drying at 80°C for 5 minutes, UV_A is applied at 120 mW / cm 2 , 2J / cm 2 The coating composition was irradiated with conditions to perform photopolymerization and photocuring, thereby forming a second coating layer (130).

[0179] As a result, a coating film (100) according to Example 1 was manufactured.

[0180] <Example 2>

[0181] A coating film was manufactured in the same manner as in Example 1, except that 2 g of the epoxy-based siloxane binder (3-glycidoxypropyl trimethoxysilane; 1.788 g) manufactured in Example 1 and 1 g of the acrylic siloxane binder (3-methacryloxypropyl trimethoxysilane; 0.899 g), 97 g of MEK, and 0.03 g of 2-Ethyl-4-methylimidazole were mixed and stirred in a flask to manufacture a first coating composition.

[0182] <Example 3>

[0183] A coating film was manufactured in the same manner as in Example 1, except that 1 g of the epoxy-based siloxane binder (3-glycidoxypropyl trimethoxysilane; 0.894 g) manufactured in Example 1 and 2 g of the acrylic siloxane binder (3-methacryloxypropyl trimethoxysilane; 1.797 g), 97 g of MEK, and 0.03 g of 2-Ethyl-4-methylimidazole were mixed and stirred in a flask to manufacture a first coating composition.

[0184] <Example 4>

[0185] The first coating layer (120) was formed in the same manner as in Example 1.

[0186] Pentaerythritol triacrylate (PETA) was used as an acrylic monomer for forming the second coating layer (130).

[0187] Specifically, a second coating composition was prepared by dissolving 3 g of PETA and 0.15 g of 2,2-dimethoxy-2-phenylacetophenone in 6 g of MEK.

[0188] After applying the coating composition manufactured above using Mayer Bar no. 16 on the formed first coating layer (120), drying at 80°C for 5 minutes, UV_A is applied at 120 mW / cm 2 , 2J / cm 2The coating composition was irradiated with conditions to perform photopolymerization and photocuring, thereby forming a second coating layer (130).

[0189] <Example 5>

[0190] The first coating layer (120) was formed in the same manner as in Example 2, and the second coating layer (130) was formed in the same manner as in Example 4.

[0191] <Example 6>

[0192] The first coating layer (120) was formed in the same manner as in Example 3, and the second coating layer (130) was formed in the same manner as in Example 4.

[0193] <Comparative Example 1>

[0194] A coating film was manufactured in the same manner as in Example 1, except that 1 g of the epoxy-based siloxane binder (3-glycidoxypropyl trimethoxysilane; 0.894 g) manufactured in Example 1 and 3 g of the acrylic siloxane binder (3-methacryloxypropyl trimethoxysilane; 2.696 g), 129 g of MEK, and 0.03 g of 2-Ethyl-4-methylimidazole were mixed and stirred in a flask to manufacture a first coating composition.

[0195] Comparative Example 2

[0196] A coating film was manufactured in the same manner as in Example 1, except that the first coating layer (120) was not formed.

[0197] Specifically, a second coating composition was prepared by first dissolving 3 g of DPHA and 0.15 g of 2,2-dimethoxy-2-phenylacetophenone in 6 g of MEK.

[0198] The second coating composition manufactured above using Mayer Bar no. 16 was applied to a 50 ㎛ thick polyimide film (CPI®, KOLON) as a base film (110), and then dried at 80°C for 5 minutes, followed by UV_A at 120 mW / cm 2 , 2J / cm 2The second coating composition was irradiated with conditions to perform photopolymerization and photocuring, thereby forming a second coating layer (130).

[0199] As a result, a coating film according to Comparative Example 2 was manufactured.

[0200] <Comparative Example 3>

[0201] A coating film was manufactured in the same manner as in Example 1, except that the first coating composition was manufactured by mixing and stirring in a flask 3 g of the epoxy siloxane binder manufactured in Example 1, 97 g of MEK, and 0.03 g of 2-Ethyl-4-methylimidazole without adding an acrylic siloxane binder.

[0202] Comparative Example 4

[0203] A coating film was manufactured in the same manner as in Example 1, except that 3 g of 3,4-Epoxycyclohexylmethyl 3,4- epoxycyclohexanecarboxylate (Sigma Aldrich), an epoxy monomer, 97 g of MEK, and 0.03 g of 2-Ethyl-4-methylimidazole were mixed and stirred in a flask to manufacture a first coating composition.

[0204] Comparative Example 5

[0205] A coating film was manufactured in the same manner as in Example 1, except that 1.5 g of 3,4-Epoxycyclohexylmethyl 3,4- epoxycyclohexanecarboxylate (Sigma Aldrich), an epoxy monomer, 1.5 g of DPHA, an acrylic monomer, 97 g of MEK, and 0.03 g of 2-Ethyl-4-methylimidazole were mixed and stirred in a flask to manufacture a first coating composition.

[0206] <Comparative Example 6>

[0207] A coating film was manufactured in the same manner as in Example 1, except that the first coating composition was manufactured by mixing and stirring in a flask 3 g of the acrylic siloxane binder manufactured in Example 1, 97 g of MEK, and 0.03 g of 2-Ethyl-4-methylimidazole without adding the epoxy siloxane binder used in Example 1.

[0208] Comparative Example 7

[0209] A coating film was manufactured in the same manner as in Example 1, except that the first coating composition was manufactured by mixing and stirring in a flask 1.5 g of the acrylic siloxane binder manufactured in Example 1, 1.5 g of DPHA, 97 g of MEK, and 0.03 g of 2-Ethyl-4-methylimidazole without adding the epoxy siloxane binder used in Example 1.

[0210] The types and contents of each component according to Examples 1 to 6 and Comparative Examples 1 to 7 can be summarized as in Table 1.

[0211] No. 1 Coating Composition (Weight, g) Second Coating Composition Epoxy Siloxane Binder Epoxy Monomer Acrylic Siloxane Binder Acrylic Monomer Acrylic Monomer Example 11.5-1.5-DPHA Example 22-1-DPHA Example 31-2DPHA Example 41.51.5PETA Example 52-1-PETA Example 61-2PETA Comparative Example 11-3-DPHA Comparative Example 2----DPHA Comparative Example 33---DPHA Comparative Example 4-3--DPHA Comparative Example 5-1.5-1.5DPHA Comparative Example 63-DPHA Comparative Example 71.51.5DPHA

[0212] * Epoxy siloxane binder: 3-glycidoxypropyl trimethoxysilane + distilled water + NaOH

[0213] * Epoxy monomer: 3,4-Epoxycyclohexylmethyl 3,4- epoxycyclohexanecarboxylate

[0214] * Acrylic siloxane binder: 3-methacryloxypropyl trimethoxysilane + distilled water + NaOH

[0215] * Acrylic monomer: DPHA

[0216] <Measurement example>

[0217] The physical properties of the coating films manufactured in Examples 1 to 6 and Comparative Examples 1 to 6 were measured according to the following method.

[0218] (1) Measurement of light transmittance (%)

[0219] Measurements were made in the wavelength range of 360 to 740 nm using a spectrophotometer according to the standard specification JIS K 7361. The spectrophotometer used was Hazemeter HM-150 / MURAKAMI COLOR RESEARCH LABORATORY.

[0220] (2) Pencil hardness measurement

[0221] Pencil hardness was measured using a pencil hardness tester from IMOTO, Japan, under conditions of a speed of 180 mm / min and a load of 750 gf according to ASTM D3363.

[0222] (3) Grid pattern peelability

[0223] Using a cutter knife (K), 100 grid patterns (130p) of 1 mm x 1 mm in size (10 x 10) were formed on the second coating layer (130) of the coating film, and 3M Scotch Box Tape (48 mm, transparent) (#3650) was attached to the surface of the second coating layer (130). When the tape was detached within 0.1 second, the number of grid patterns of the second coating layer (130) that were separated from the coating film and attached to the tape was measured.

[0224] The grid pattern (130p) can be formed by the method illustrated in FIG. 9. By forming grid grooves (130s) in the second coating layer (130) using a cutter knife (K), the grid pattern (130p) can be created. When forming the grid pattern (130p) in the second coating layer (130) using the cutter knife (K), only the second coating layer (130) is cut, and the base film (110) and the first coating layer (120) are not cut. The first coating layer (120) may also be partially cut.

[0225] The grid pattern peelability was measured for the coating films manufactured in the examples and comparative examples (measured before heat treatment), and the grid pattern peelability was measured again after the coating films were heat treated at 230°C for 1 hour.

[0226] (4) Confirmation of interlayer bonding polymer (140)

[0227] Using IR Spectroscopy, it was confirmed whether an interlayer bonded polymer (140) was present across the first coating layer (120) and the second coating layer (130). Specifically, through IR Spectroscopy, unreacted acrylic groups (1700-1750 cm) were detected in the first coating layer (120). -1 ) was confirmed to exist. The interlayer bonding polymer (140) was confirmed through the presence of surface reaction molecules.

[0228] More specifically, according to the embodiments and comparative examples of the present invention, after the formation of the first coating layer (120) and before the formation of the second coating layer (130), the monomer remaining in the first coating layer (120) is an acrylic monomer, and since unreacted acrylic monomer also exists on the surface of the first coating layer (120), the acrylic monomer corresponds to a surface-reactive molecule. In the embodiments of the present invention, an acrylic siloxane monomer may correspond to the unreacted acrylic monomer.

[0229] In IR Spectroscopy, unreacted acrylic groups (1700-1750 cm) were observed as surface-reactive molecules. -1) means that when the second coating layer (130) is formed, unreacted acrylic monomers (acrylic siloxane monomers) that can participate in polymerization exist inside and on the surface of the first coating layer (120). When the unreacted acrylic monomers that existed inside and on the surface of the first coating layer (120) participate in polymerization, as shown in FIGS. 2 and 4, the unreacted acrylic monomers (acrylic siloxane monomers) of the first coating layer (120) and the acrylic monomers of the second coating composition (131) can react, and as a result, an interlayer bonding polymer (140) can be formed. Therefore, in IR Spectroscopy, unreacted acrylic groups (1700-1750 cm) that are surface-reactive molecules -1 ) exists, it means that an interlayer bonded polymer (140) can be formed.

[0230] (5) Yellowness measurement

[0231] Yellowness was measured using a spectrophotometer (CM-3700D, KONICA MINOLTA) according to the standard ASTM E313.

[0232] The yellowness of the coating films manufactured in the examples and comparative examples was measured (measured before heat treatment), and the yellowness was measured again after the coating films were heat treated at 230˚C for 1 hour.

[0233] The above measurement results are disclosed in Table 2 below.

[0234] Number Light transmittance Yellowness Pencil hardness Lattice pattern Peelability Surface reaction Molecule presence Interlayer bonding Polymer presence 230℃, after 1 hour Lattice pattern Peelability Yellowness Example 1 90.5 2.5 4H0 / 100YY0 / 100 2.5 Example 2 90.5 2.5 4H0 / 100YY0 / 100 2.5 Example 3 90.5 2.5 4H0 / 100YY0 / 100 2.5 Example 4 90.5 2.5 4H0 / 100YY0 / 100 2.5 Example 5 90.5 2.5 4H0 / 100YY0 / 100 2.5 Example 6 90.5 2.5 4H0 / 100YY0 / 100 2.5 Comparative example 190.32.54H15 / 100YY10 / 1002.5Comparative example 289.52.53H56 / 100NN58 / 1002.5Comparative example 390.22.53H48 / 100NN50 / 1002.5Comparative example 489.82.53H50 / 100NN52 / 1002.7Comparative example 589.92.54H13 / 100YY15 / 1002.7Comparative example 689.52.53H100 / 100YY5 / 1002.5Comparative example 789.52.53H100 / 100YY7 / 1002.5

[0235] In the “Presence of interlayer bonding polymer” entry in Table 2, “Y” means that interlayer bonding polymer is present, and “N” means that interlayer bonding polymer is not present.

[0236] Additionally, in the “Presence of surface-reactive molecules” entry in Table 2, “Y” means that surface-reactive molecules exist, and “N” means that surface-reactive molecules do not exist.

[0237] Referring to Table 2, it was confirmed that the coating films (100) according to Examples 1 to 6 had a light transmittance of 90% or more, a pencil hardness of 4H or more, and a grid pattern peelability of one or less.

[0238] In Comparative Example 1, since an acrylic siloxane binder is used in an excess amount (more than 70 wt%) in the first coating composition, an acrylic siloxane monomer is present in an excess amount (more than 70 wt%) in the first coating composition. As a result, an excess amount of unreacted acrylate is present in the first coating layer in the second coating layer forming step, and it can be confirmed that the grid pattern peelability of the optical film manufactured in Comparative Example 1 is weakened compared to the examples.

[0239] In Comparative Example 2, which does not include the first coating layer (120) that acts as an interface layer or adhesion promoting layer, no interlayer bonding polymer was formed, and it was confirmed that lattice pattern peeling occurred, and a corresponding decrease in pencil hardness was confirmed.

[0240] In Comparative Example 3, where no acrylic siloxane binder or acrylic monomer was used, no interlayer bonding polymer was formed, resulting in lattice pattern delamination and a decrease in pencil hardness.

[0241] In Comparative Example 4, where no acrylic siloxane binder or acrylic monomer was used, no interlayer bonding polymer was formed. In addition, Comparative Example 4, which does not include a siloxane monomer, showed a relative decrease in light transmittance, delamination of the grid pattern, and a decrease in pencil hardness. In addition, a decrease in heat resistance was also confirmed as yellowness increased after high-temperature treatment.

[0242] In Comparative Example 5, which did not use a siloxane binder containing a siloxane monomer, interlayer bonding polymers were formed, but a decrease in light transmittance and delamination of the lattice pattern were observed. In Comparative Example 5, there was no decrease in pencil hardness, but an increase in yellowness was observed after high-temperature treatment.

[0243] Comparative Examples 6 and 7, in which a first coating composition containing an acrylic siloxane binder and an acrylic monomer, but not an epoxy monomer and an epoxy siloxane binder, was used, showed severe grid pattern peeling and a decrease in pencil hardness due to the presence of a large amount of unreacted acrylic in the first coating layer.

[0244] On the other hand, it can be confirmed that the coating film according to the embodiments of the present invention (Examples 1-6) has excellent surface properties and excellent adhesiveness.

[0245] In this way, the coating film according to one embodiment of the present invention has excellent hardness and scratch resistance and excellent adhesiveness, and thus can be usefully used as a cover window or protective film of a display device.

[0246] [Explanation of symbols]

[0247] 100: Coating film

[0248] 110: Base film

[0249] 120: First coating layer

[0250] 120: Second coating layer

[0251] 200: Display device

[0252] 501: Display panel

[0253] 570: Organic light-emitting device

[0254] TFT: Thin Film Transistor

Claims

1. Base film; A first coating layer on the above-mentioned substrate film; a second coating layer on the first coating layer; and It comprises an interlayer bonding polymer disposed across the first coating layer and the second coating layer, Coating film having a grid pattern peelability of 1 or less: Here, the grid pattern peelability is a value obtained by measuring the number of grid patterns of the second coating layer that are separated from the coating film and attached to the tape when 100 grid patterns (10 x 10) of 1 mm x 1 mm size are formed on the second coating layer of the coating film using a cutter knife, 3M Scotch Box Tape (48 mm, transparent) (#3650) is attached to the surface of the second coating layer, and the tape is removed within 0.1 second.

2. In paragraph 1, A coating film, wherein one end of the interlayer bonding polymer is positioned in the first coating layer, and the other end of the interlayer bonding polymer is positioned in the second coating layer.

3. In paragraph 1, The above interlayer bonding polymer is a coating film formed by polymerization of a photopolymerizable monomer.

4. In paragraph 1, A coating film wherein the interlayer bonding polymer comprises an acrylic polymer.

5. In paragraph 4, A coating film, wherein the second coating layer comprises an acrylic polymer resin.

6. In paragraph 1, The first coating layer is a coating film formed by a first coating composition containing an epoxy-based siloxane monomer and an acrylic-based siloxane monomer.

7. In paragraph 6, A coating film, wherein the first coating layer comprises the acrylic siloxane monomer.

8. In paragraph 6, The second coating layer is formed by photopolymerization of an acrylic composition, A coating film in which the interlayer bonding polymer is formed by photopolymerization of an acrylic siloxane monomer included in the first coating composition and the acrylic composition for forming the second coating layer.

9. In paragraph 1, A coating film having a light transmittance of 90% or more.

10. In paragraph 1, A coating film, wherein the second coating layer has a pencil hardness of 4H or higher.

11. A step of applying a first coating composition on a substrate film; A step of forming a first coating layer by applying heat to the first coating composition; A step of applying a second coating composition on the first coating layer; and A step of forming a second coating layer by irradiating the second coating composition with light; The first coating composition comprises an epoxy siloxane monomer and an acrylic siloxane monomer, The second coating composition comprises an acrylic monomer, A method for manufacturing a coating film, wherein the content of the epoxy-based siloxane monomer is 30 to 70 wt% and the content of the acrylic siloxane monomer is 30 to 70 wt% based on the total weight of the monomers included in the first coating composition.

12. In paragraph 11, A method for manufacturing a coating film, wherein, in the step of forming the second coating layer, the acrylic siloxane monomer included in the first coating layer and the acrylic monomer included in the second coating composition are polymerized by the light irradiation, thereby forming an interlayer bonding polymer across the first coating layer and the second coating layer.

13. In paragraph 11, A method for manufacturing a coating film, wherein, in the step of applying a second coating composition on the first coating layer, the epoxy-based siloxane monomer is in a polymerized state and the acrylic-based siloxane monomer is in a non-polymerized state.

14. Display panel; and A coating film according to any one of claims 1 to 13, disposed on the display panel; A display device including:

Images