Optical laminate and image display device comprising same

Abstract

The present invention relates to an optical laminate and an image display device comprising same, the optical laminate comprising: a thin film glass; a first hard coating layer formed on one surface or both surfaces of the thin film glass; and a second hard coating layer formed on the first hard coating layer, wherein the first hard coating layer includes a thermosetting resin and a UV absorber, and the second hard coating layer includes a light-transmitting resin, and can provide the optical laminate and the image display device comprising same, the first hard coating layer having sufficient impact resistance, including the UV absorber so as to able to block 95% or more of ultraviolet rays with a wavelength of 300-380 nm, having excellent spectral transmittance of 80% or higher in the 440 nm wavelength region, and having excellent hardness, scratch resistance, adhesiveness and flexibility.

Description

Optical laminate and image display device including the same

[0001] The present invention relates to an optical laminate and an image display device including the same.

[0002]

[0003] Recently, image display devices, such as liquid crystal displays (LCDs) and organic light emitting displays (OLEDs), have been continuously thinning and becoming more flexible. These image display devices are widely used in various smart devices characterized by portability, including not only smartphones and tablet PCs, but also various wearable devices. Such flexible displays require a glass substrate layer with properties such as high transparency, impact resistance, and bending characteristics.

[0004] Meanwhile, cover windows for flexible displays are thin and fragile, so they must be reinforced with a separate substrate. OLED-based devices, in particular, are vulnerable to UV, and if they do not include a polymer film containing a UV absorber, there is a concern that the lifespan of the display panel will be shortened due to the lack of UV blocking function. Therefore, a separate substrate capable of blocking UV is absolutely necessary. However, the composition forming the hard coating layer generally contains a photocurable resin, making it difficult to simultaneously include a UV absorber. Therefore, it is difficult for a flexible display to block UV and improve impact resistance with only a hard coating layer without a separate substrate.

[0005] Korean Patent Publication No. 10-2018-0043490 provides a composition for forming a hard coating film that has impact resistance equivalent to tempered glass while simultaneously improving flexibility for flexible properties. However, in the case of such conventional compositions for forming hard coating films for flexible displays, the UV blocking ability of the hard coating layer including a UV absorber is limited because a photocurable resin is used. This is because benzotriazole-based and benzophenone-based UV stabilizers, which are typically used as UV absorbers or UV stabilizers, exhibit absorption spectra that overlap with the absorption wavelength range of the photopolymerization initiator, which can inhibit the photocuring of the resin.

[0006] Therefore, there is a need to develop an optical laminate that not only provides sufficient impact resistance to flexible displays but also has a hard coating layer that enables effective UV blocking without a separate substrate.

[0007]

[0008] The present invention aims to provide an optical laminate including a hard coating layer that can block 95% or more of ultraviolet rays having a wavelength of 300 nm to 380 nm, has an excellent spectral transmittance of 80% or more at a wavelength of 440 nm, and has improved impact resistance by including a thermosetting resin and a UV absorber together to solve the above-described problem.

[0009] Specifically, the present invention aims to provide an optical laminate having a second hard coating layer having sufficient hardness and scratch resistance formed on a first hard coating layer having impact resistance, UV protection, and excellent adhesion, and an image display device including the same.

[0010] More specifically, the optical laminate of the present invention has excellent bendability and thus can be applied to a flexible display.

[0011] However, the problems to be solved by the present invention are not limited to the problems mentioned above, and other problems not mentioned will be clearly understood by those skilled in the art from the description below.

[0012]

[0013] In order to achieve the above technical task, the present invention provides an optical laminate comprising: a thin film glass; a first hard coating layer formed on one or both sides of the thin film glass; and a second hard coating layer formed on the first hard coating layer; wherein the first hard coating layer includes a thermosetting resin and a UV absorber, and the second hard coating layer includes a light-transmitting resin.

[0014] In the present invention, the UV absorber may be at least one selected from among benzophenone-based and benzotriazole-based UV absorbers.

[0015] In the present invention, the thermosetting resin may include an alkoxysilane group and an epoxy group.

[0016] In the present invention, the thermosetting resin may be an acrylic polyol-based resin.

[0017] In the present invention, the first hard coating layer is formed from a first hard coating composition, and in the present invention, the first hard coating composition may contain 0.5 to 2.0 parts by weight of a UV absorber relative to 100 parts by weight of the total composition.

[0018] In the present invention, the light-transmitting resin may be manufactured by including at least one selected from epoxy (meth)acrylate, urethane (meth)acrylate, and ester (meth)acrylate.

[0019] In the present invention, the second hard coating layer is formed from a second hard coating composition, and the second hard coating composition may include a dendrimer compound.

[0020] In the present invention, it may be characterized in that the spectral transmittance is 5% or less in the wavelength range of 300 nm to 380 nm, and the spectral transmittance is 80% or more at 440 nm.

[0021] In the present invention, the thickness of the thin film glass may be 10 to 100 μm.

[0022] In the present invention, when the first hard coating layer exists only on one side of the thin film glass, the thickness of the first hard coating layer may be 20 to 70 μm.

[0023] In the present invention, when the first hard coating layer exists on both sides of the thin film glass, the thickness of the first hard coating layer may be 10 to 40 ㎛, respectively.

[0024] In the present invention, the thickness of the second hard coating layer may be 10 μm or less.

[0025] In the present invention, the thin film glass may include a flat portion and a curved portion.

[0026] In the present invention, the first hard coating layer further includes an epoxy silane coupling agent, and the epoxy silane coupling agent may include at least one selected from 3-glycidoxypropyldimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 8-glycidoxyoctyltrimethoxysilane, and 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane.

[0027] In the present invention, the thin film glass, the first hard coating layer, and the second hard coating layer may be formed in direct contact with each other without including a separate layer.

[0028] The present invention may be applied to a flexible display.

[0029] In addition, the present invention provides an image display device including the optical laminate.

[0030]

[0031] The optical laminate according to the present invention and the image display device including the same include a hard coating layer including a UV absorber, thereby having excellent blocking of ultraviolet rays with a wavelength of 300 to 380 nm, and excellent spectral transmittance at a wavelength of 440 nm, so that sufficient visible light is transmitted while excellently blocking ultraviolet rays, and the hardness, scratch resistance, and impact resistance of the display are improved, and sufficient total light transmittance and haze that does not affect visibility are possible.

[0032] In addition, the optical laminate according to the present invention may further form a second hard coating layer including a light-transmitting resin on a first hard coating layer including a thermosetting resin and a UV absorber, so that the adhesion between the two hard coating layers is further improved.

[0033] In addition, the optical laminate according to the present invention may be more suitable for a flexible display, as it includes a first hard coating layer and a second hard coating layer having excellent bendability.

[0034] In addition, the optical laminate according to the present invention is formed through direct contact between the glass and the hard coating layer without including a separate substrate between them, so that a process for bonding each substrate layer can be omitted, and thus the manufacturing process can be simplified compared to the conventional one.

[0035]

[0036] FIG. 1 illustrates a laminated structure of an optical laminate according to one embodiment of the present invention, and is a drawing expressing that a first hard coating layer is formed only on one side of a thin film glass.

[0037] FIG. 2 is a diagram illustrating a laminated structure of an optical laminate according to one embodiment of the present invention, in which a first hard coating layer is formed on both sides of a thin film glass.

[0038] In the above drawing, each symbol represents the following:

[0039] 100: Optical laminate

[0040] 110: Thin film glass

[0041] 120a: First hard coating layer (a)

[0042] 120b: First hard coating layer (b)

[0043] 130: Second hard coating layer

[0044]

[0045] The present invention relates to an optical laminate comprising a thin film glass, a first hard coating layer formed on one or both sides of the thin film glass, and a second hard coating layer formed on the first hard coating layer, wherein the first hard coating layer comprises a thermosetting resin and a UV absorber, and the second hard coating layer comprises a light-transmitting resin, and to an image display device comprising the same. Furthermore, the optical laminate comprises two hard coating layers of the present invention, and has sufficient total light transmittance and haze that does not affect visibility.

[0046]

[0047] Hereinafter, preferred embodiments of the present invention will be described in detail. However, these examples are provided solely as examples to more specifically illustrate the present invention, and it will be apparent to those skilled in the art that the scope of the present invention is not limited by these examples.

[0048] The terms used herein are for the purpose of describing embodiments and are not intended to limit the present invention. In this specification, singular forms also include plural forms, unless specifically stated otherwise. For example, "hard coating layer" as used herein may refer to at least one of the first hard coating layer and the second hard coating layer.

[0049] As used herein, the terms "comprises" and / or "comprising" are used to mean that they do not exclude the presence or addition of one or more other components, steps, operations, and / or elements other than the components, steps, operations, and / or elements mentioned. Like reference numerals refer to like elements throughout the specification.

[0050] As used herein, “transparent” means having a visible light transmittance of 70% or more or 80% or more.

[0051] The term 'manufacturing' as used in this specification is a general term for the process of creating a component through a reaction, such as synthesis or polymerization of a compound.

[0052]

[0053] FIG. 1 illustrates a laminated structure of an optical laminate according to one embodiment of the present invention, and is a diagram expressing that a first hard coating layer is formed only on one side of a thin film glass. As illustrated in FIG. 1, the optical laminate (100) of the present invention may have a structure including glass (110); a first hard coating layer (120a) formed on the glass (110); and a second hard coating layer (130) formed on the first hard coating layer, i.e., on the outermost side.

[0054] The optical laminate of the present invention can simultaneously have substrate adhesion, UV blocking power, impact resistance, hardness, and bendability for application to a window for a flexible display.

[0055]

[0056] Optical laminate

[0057] The optical laminate of the present invention comprises glass and a hard coating layer, and preferably may comprise a first hard coating layer and a second hard coating layer. More specifically, the first hard coating layer is formed of a first hard coating composition, the second hard coating layer is formed of a second hard coating composition, and the optical laminate of the present invention relates to an optical laminate comprising: thin film glass; a first hard coating layer formed on one or both sides of the thin film glass; and a second hard coating layer formed on the first hard coating layer. More specifically, the first hard coating layer may comprise a thermosetting resin and a UV absorber, and the second hard coating layer may comprise a light-transmitting resin. In the present invention, the thin film glass, the first hard coating layer, and the second hard coating layer may be formed in direct contact with each other without comprising a separate layer.

[0058]

[0059] Thin film glass (110)

[0060] The above-described thin film glass is intended to replace an existing glass substrate and support a hard coating layer (120, 130) and other substrates or panels, which will be described later, and may include flat and curved portions for the display of an electronic device. The above-described thin film glass may include, for example, flat glass, flexible glass, and curved glass.

[0061] The above-described thin film glass may have the same thickness overall, and according to another embodiment of the present invention, may have flat portions and curved portions with different thicknesses partially at one or more locations as needed. The curved portion refers to a portion that is formed by slimming to a thinner thickness compared to the flat portion, and the curved portion may be an area corresponding to a region where a flexible display is folded in half or a folding portion that is bent in the case of ultra-thin glass (UTG). In this case, the folding portion may include both in-folding and out-folding.

[0062] For example, the thin film glass of the present invention may have different thicknesses for the flat and curved portions, as needed. For example, the thickness of the curved portion may be thinner than that of the flat portion. The curved portion may be located or shaped in a manner recognized in the art as an edge portion, may be one portion or multiple portions, and may be located in the center of the thin film glass.

[0063] When the hard coating layer of the present invention, which will be described later, is applied to thin film glass, the form of the application can be appropriately adjusted depending on the form of the thin film glass. For example, the hard coating layer can be applied with a uniform thickness along the surface of the thin film glass, and the hard coating layer applied on the thin film glass can be partially varied. In particular, when the thickness of the thin film glass is partially different, the hard coating layer applied on the thin film glass can be partially varied so that the optical laminate to which the hard coating layer is applied has an overall flat surface, or the hard coating layer can be applied with a uniform thickness so that the optical laminate has an overall different thickness.

[0064] Specifically, when the optical laminate according to one embodiment of the present invention is applied to a thin film glass including a downwardly concave curved portion, the first hard coating composition applied to one surface of the thin film glass may be applied until a desired first hard coating layer thickness is formed based on the flat portion. Alternatively, the first hard coating composition may be applied with a constant thickness along the curved shape of the thin film glass curved portion, and then the second hard coating composition may be applied until a desired second hard coating layer thickness is formed based on the flat portion. Alternatively, the first hard coating composition may be applied with a constant thickness along the curved shape of the thin film glass curved portion, and then the second hard coating composition may be applied with a constant thickness along the curved shape of the first hard coating layer.

[0065] According to one embodiment of the present invention, any transparent glass can be used as the glass (110), and preferably, silicate glass can be used. The silicate glass is a glass mainly composed of anhydrous silica (silica) that exists naturally in the form of silica sand. The structure of the silicate glass has a very high density and very strong bonds with oxygen and water, so it exhibits low transmittance, making it suitable for use as a display substrate.

[0066] In addition, it is preferable that the glass used in the above-mentioned description be thin glass (thin glass, TG) having a thickness of 10 to 300 ㎛. Unlike existing glass, it is more preferable to have a thickness of 100 ㎛ or less in order to have excellent bending resistance that does not break even when bent or folded for use in a flexible display substrate. Glass thinner than 10 ㎛ has the problem of being easily broken during the manufacturing process.

[0067] The optical laminate according to the present invention may include an additional substrate layer, such as a hard coating layer (120, 130) to be described later, to ensure the durability of the glass (110). Generally, an adhesive layer or a pressure-sensitive adhesive layer is included to form or bond the substrate layer, but the optical laminate according to the present invention is characterized in that it is formed through direct contact without including a separate substrate layer for bonding the hard coating layer, so that the manufacturing process can be simplified compared to a conventional laminate.

[0068]

[0069] Hard coating layer (120, 130)

[0070] The hard coating layer of the present invention may include a first hard coating layer (120a) and a second hard coating layer (130), as shown in FIG. 1.

[0071] According to one embodiment of the present invention, the first hard coating layer (120a) is characterized by being formed of a first hard coating composition including a thermosetting resin and a UV absorber, and by including the thermosetting resin and the UV absorber, UV blocking is possible and adhesion to the glass (110) and impact resistance can be secured. The second hard coating layer (130) is characterized by being formed of a second hard coating composition including a light-transmitting resin, and can have scratch resistance and high hardness properties.

[0072] Referring to Fig. 1, the first hard coating layer (120a) is formed on one surface of the thin film glass (110), and the second hard coating layer (130) can be formed on the first hard coating layer (120a), i.e., on the outermost surface of the optical laminate. The first hard coating layer (120a) secures adhesion between substrates and provides impact resistance without a separate substrate layer such as an adhesive layer.

[0073] As another example of the present invention, referring to FIG. 2, the first hard coating layer (120a, 120b) is formed on both sides of the thin film glass (110), and the second hard coating layer (130) can be formed on the first hard coating layer (120a) of any one of the first hard coating layers on both sides, i.e., on the outermost surface of the optical laminate.

[0074] In addition, the first hard coating composition and the second hard coating composition may each independently further include at least one selected from the group consisting of an additive, an initiator, and a solvent, and the additive may include at least one selected from the group consisting of a silicone-based leveling agent and a heat stabilizer. For example, the first hard coating layer may be prepared from a hard coating composition including an epoxy acrylic resin, an epoxy silane coupling agent, a silicone-based leveling agent, an initiator, and a solvent, and the second hard coating layer may be prepared from a hard coating composition including a light-transmitting resin, a silicone-based leveling agent, an initiator, and a solvent.

[0075]

[0076] First hard coating layer

[0077] The first hard coating layer of the present invention is formed from a first hard coating composition containing a thermosetting resin and a UV absorber, and the first hard coating layer of the present invention can secure sufficient curing degree and improve impact resistance by containing a thermosetting resin, and can improve the reliability of the display device by blocking ultraviolet light transmitted into the interior of the display device including the optical laminate of the present invention by having a UV absorber and thus having a UV blocking effect.

[0078]

[0079] thermosetting resin

[0080] As the above thermosetting resin, a transparent resin that can form a hard coating layer with improved substrate adhesion by forming cross-linking bonds by heat can be used.

[0081] Conventional hard coat films typically use UV-curable resins that can be cured in a short time without applying high temperatures by forming a coating layer on a polymer substrate film through roll-to-roll coating. However, when a UV absorber is included in the coating layer, there is a problem that it is difficult to use UV-curable materials. Therefore, the first hard coating composition of the present invention is characterized by including a thermosetting resin that can be cured without the influence of a UV absorber. In addition, when a thermosetting resin is used, batch coating, rather than roll-to-roll coating, can be performed for the purpose of application to a glass substrate, which is preferable in that there are few restrictions on the curing temperature and time. It is preferable to use an acrylic polyol-based resin that has excellent adhesion to glass as the thermosetting resin, and it is preferable to cure it for 5 to 30 minutes within a range of 60°C to 150°C.

[0082] The thermosetting resin may include an alkoxysilane group capable of reacting with glass and an epoxy group capable of forming an organic bond between the resin. When the alkoxysilane group and the epoxy group are included, adhesion to a non-metallic material is improved, so it is particularly preferable in terms of improved adhesion when forming a first hard coating layer (120a or 120b) on one surface of a thin film glass as shown in FIGS. 1 and 2, which illustrate an example of the present invention. In addition, by including an alkoxysilane group and an epoxy group, it can have rubber elasticity after curing, so that impact resistance can be secured. The thermosetting resin of the present disclosure may have an elastic modulus range of 1 MPa to 3,000 MPa after curing, and when the above range is satisfied, it is more preferable in terms of securing impact resistance.

[0083] The thermosetting resin of the first hard coating composition according to the present invention may include a non-functional (meth)acrylic monomer, a hydroxyl group-containing (meth)acrylic monomer, a vinyl monomer, etc., and may be a resin modified with an alkoxysilane group and an epoxy group to improve adhesion to a non-metallic material.

[0084] Thermosetting resins that can be used in the present invention include non-functional (meth)acrylic monomers such as methyl methacrylate, ethyl methacrylate, isobutyl methacrylate, normal butyl methacrylate, normal hexyl methacrylate, 2-ethylhexyl methacrylate, isobornyl methacrylate, cyclohexyl methacrylate, methyl acrylate, propyl acrylate, isobutyl acrylate, normal butyl acrylate, tert-butyl acrylate, 2-ethylhexylacrylate, normal octylacrylate, isobornyl acrylate, and cyclohexylacrylate; It may include a hydroxyl group-containing (meth)acrylic monomer such as 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, 4-hydroxybutyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 4-hydroxybutyl methacrylate, caprolactone acrylate, 2,3-dihydroxypropyl acrylate, 2,3-dihydroxypropyl methacrylate, polypropylene-modified acrylate, or polypropylene-modified methacrylate; a vinyl monomer such as styrene, vinyltoluene, vinyl acetate, or α-methylstyrene.

[0085] As commercially available products of the above thermosetting resin, SC-330L-4 and EXCELOL813 of Asia Industrial Co., Ltd., which are two-component curable acrylic polyols with strong adhesiveness to glass, can be used, but are not limited thereto.

[0086] The thermosetting resin is preferably included in an amount of 10 to 80 parts by weight, and more preferably 40 to 60 parts by weight, based on 100 parts by weight of the total of the first hard coating composition. If it is less than 10 parts by weight, thick film coating is impossible, resulting in a decrease in hardness. If it is more than 80 parts by weight, the solubility of the composition is reduced, and the viscosity increases, making it difficult to secure coating properties.

[0087]

[0088] UV absorber

[0089] UV absorbers are a type of light stabilizer that plays a role in resolving decomposition by polyolefin, so they are expressed as ultraviolet stabilizers and are also called UV agents.

[0090] The above UV stabilizers can be classified into absorbers, quenchers, and hindered amine light stabilizers (HALS) according to their mechanism of action, or into phenyl salicylates (absorbers), benzophenone (absorbers), benzotriazole (absorbers), nickel derivatives (quenchers), and radical scavengers according to their chemical structures. However, the present invention is characterized in that it includes a UV absorber that directly absorbs UV rays of 300 to 380 nm, rather than a UV agent that reduces damage caused by UV by stabilizing radicals generated by absorbing UV rays of 300 to 380 nm, such as hindered amine light stabilizers (HALS) or radical scavengers.

[0091] The UV absorber included in the first hard coating composition of the present invention may be at least one selected from the group consisting of triazine-based, benzotriazole-based, and benzophenone-based UV absorbers that absorb UV in the wavelength range of 200 to 380 nm, convert it into infrared energy, and emit it. Among these, the inclusion of a benzotriazole-based and / or benzophenone-based UV absorber is particularly preferable in terms of improving the light resistance of the optical laminate including the first hard coating layer of the present invention and minimizing the reduction in transmittance of light of a wavelength of 440 nm. The spectral transmittance at a wavelength of 440 nm is the transmittance of visible light, and must be 80% or more to avoid reducing the clarity of the display including the optical laminate. Meanwhile, it is preferable that the first hard coating composition of the present invention not include an indole-based UV absorber, and if an indole-based UV absorber is included, the spectral transmittance at a wavelength of 440 nm is significantly lower than 80%, so that the transmittance of visible light is poor, which is disadvantageous in terms of the clarity of the display.

[0092] As the benzotriazole UV absorber, known compounds can be used. Specifically, octyl 3-[3-tert-butyl-4-hydroxy-5-(5-chloro-2H-benzotriazol-2-yl)phenyl]propionate, 2-ethylhexyl 3-(3-tert-butyl-4-hydroxy-5-(5-chloro-2H-benzotriazol-2-yl)phenyl)propionate, [3-[3-(2H-benzotriazol-2-yl)-5-(1,1-methylethyl)-4-hydroxyphenyl]-1-oxopropyl]-w-[3-[3-(2H-benzotriazol-2-yl)-5-(1,1-dimethylethyl)-4-hydroxyphenyl]-1-oxopropoxy]poly(oxy-1,2-ethanediyl), (3-(3-(2H-benzotriazol-2-yl)-5-(1,1-dimethylethyl)-4-hydroxyphenyl)-1-oxopropyl)-hydroxypoly(oxo-1,2-ethanediyl), 2-(2H-benzotriazol-2-yl)-4,6-diteretpentylphenol, 3-(2H-benzotriazolyl)-5-(1,1-dimethylethyl)-4-hydroxy-benzinepropionic acid octyl ester, 2-(2H-benzotriazol-2-yl)-4,6-bis(1-methyl-1-phenylethyl)phenol, 2-(2H-benzotriazol-2-yl)-6-(1-methyl-1-phenylethyl)-4-(1,1,3,3-tetramethylbutyl)phenol, etc. are preferable.

[0093] Known compounds can be used as benzophenone-based UV absorbers. Specifically, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-octoxybenzophenone, 2,2'-di-hydroxy-4-methoxybenzophenone, etc. can be provided.

[0094] Examples of commercially available UV absorbers with a maximum absorption wavelength between 200 and 380 nm include triazines such as TINUVIN 479, TINUVIN 460, TINUVIN 477 from BASF, and ADK STAB LA-F70, ADK STAB LA-46 from Adeka; benzotriazoles such as TINUVIN 109, TINUVIN 326, TINUVIN 328, TINUVIN 384-2, TINUVIN 99-2, TINUVIN 900, TINUVIN 928, TINUVIN 1130 from BASF; Benzophenone-based UV absorbers include Chimassorb 81 and Chimassorb 90 from BASF, Dainsorb P-7 from Daiwa Kasei, and ADK STAB 1413 from Adeka. These UV absorbers can be used alone or in combination of two or more. These UV absorbers have the property of absorbing and blocking ultraviolet rays in the wavelength range of 200 to 380 nm, which overlaps with the absorption wavelength of photoinitiators used in general photocurable coating compositions. However, since the first hard coating composition of the present invention includes a thermosetting resin, loss of curing degree due to inclusion of the UV absorber may not occur.

[0095] According to one embodiment of the present invention, an optical laminate can satisfy a spectral transmittance of 5% or less in a wavelength range of 300 nm to 380 nm and a spectral transmittance of 80% or more at a wavelength of 440 nm. The wavelength range of 300 nm to 380 nm is a range that includes both UVA and UVB, and in the present invention, the degree of UV blocking is defined as the transmittance at a UV transmission wavelength of 380 nm. The optical laminate according to the present invention can block UV rays of 95% or more at a wavelength of 300 nm to 380 nm in a range of 1 to 5% in UV transmittance at a wavelength of 380 nm. When the UV blocking rate satisfies the above range, not only can damage to the liquid crystal layer caused by external light be prevented, but also the light resistance is excellent without color change, so that it can be effectively used to protect a display.

[0096] The amount of the UV absorber can be adjusted depending on the coating thickness, and specifically, it is preferable to use 0.5 to 2.0 parts by weight based on 100 parts by weight of the first hard coating composition, in order to minimize changes in the properties of the hard coating composition and maintain excellent curability of the composition. If it is less than 0.5 parts by weight, a sufficient UV blocking effect cannot be obtained, and if it exceeds 2.0 parts by weight, excessive addition may cause problems such as deterioration of the adhesive properties, such as surface migration of the UV absorber.

[0097]

[0098] Epoxy silane coupling agent

[0099] The above first hard coating composition further includes an epoxy silane coupling agent, and the epoxy silane coupling agent may include at least one selected from 3-glycidoxypropyldimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 8-glycidoxyoctyltrimethoxysilane, and 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane.

[0100] The above epoxy silane coupling agent refers to a compound having an epoxy group in the organic reactive group of the silane coupling agent. Specifically, R1 x -Si-(OR2) 4-x In the structure, it refers to a compound containing an epoxy group in R1. (X is an integer of 1 to 3, and R2 is an alkyl group such as methyl, ethyl, or propyl.) For example, the epoxy silane coupling agent may include at least one selected from 3-glycidoxypropyldimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 8-glycidoxyoctyltrimethoxysilane, and 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane.

[0101] Commercially available products of the above epoxy silane coupling agent include Shin-Etsu's KBM-303, KBM-402, KBM-403, KBM-4803, KBE-402, KBE-403, X-12-981S, X-12-984S, KR-516, and KR-517.

[0102] The above epoxy silane coupling agent may be included preferably in an amount of 1 to 30 parts by weight, more preferably 2 to 10 parts by weight, based on 100 parts by weight of the total hard coating composition. By including the epoxy silane coupling agent within the above range, adhesion to glass is improved and flexibility can be provided to the hard coating layer. If it is less than the above range, there is a problem that adhesion to glass is not sufficiently secured, and if it exceeds the above range, there is a concern that optical properties may deteriorate due to scattering due to poor compatibility.

[0103]

[0104] additives

[0105] In addition, the hard coating composition used to form the first hard coating layer and the second hard coating layer according to the present invention may further include additives such as a leveling agent and / or a heat stabilizer.

[0106] Leveling agent is a component that provides smoothness and coating properties to the coating film.

[0107] Leveling agents can be applied using leveling agents commonly used in the industry, such as silicone-based leveling agents, fluorine-based leveling agents, and acrylic polymer-based leveling agents. These may be used alone or in combination of two or more, but are not necessarily limited to these.

[0108] Commercially available products of the above leveling agent include BYK-306, BYK-307, BYK-323, BYK-331, BYK-333, BYK-337, BYK-373, BYK-375, BYK-377, BYK-378, BYK-UV3500, BYK-UV3505, BYK-UV3530, BYK-UV3535, BYK-3560, BYK-358N, BYK-361N from BYK Chemical; Daegu Corporation's TEGO Glide 410, TEGO Glide 411, TEGO Glide 415, TEGO Glide 420, TEGO Glide 432, TEGO Glide 435, TEGO Glide 440, TEGO Glide 450, TEGO Glide 455, TEGO Rad 2100, TEGO Rad 2200N, TEGO Rad 2250, TEGO Rad 2300, TEGO Rad 2500; 3M Corporation's FC-4430, FC-4432, etc. can be used, but are not limited thereto, and leveling agents commonly used in the art can be applied.

[0109] The leveling agent may be included in an amount of 0.1 to 1 part by weight per 100 parts by weight of the hard coating composition, but is not limited thereto. However, when the leveling agent is included in the hard coating composition within the above range, there is an advantage in that the smoothness and coatability of the coating film can be maximized while maintaining the hardness and flexibility excellently.

[0110] Heat stabilizers include, for example, commercially applicable products, primary heat stabilizers such as polyphenols, secondary heat stabilizers such as phosphates, and lactones, which can be used singly or in combination. These can be used singly or in combination of two or more types. The heat stabilizers can be used by appropriately adjusting the content so as not to affect thermosetting properties.

[0111] The above additives can be added by appropriately adjusting the content within a range that does not impede the effects of the present invention.

[0112]

[0113] solvent

[0114] The solvent included in the hard coating composition used for forming the first hard coating layer and the second hard coating layer according to the present invention can be used without limitation as long as it is known as a solvent for a composition for forming a coating layer in the technical field of the present invention, and can dissolve or disperse the composition mentioned above.

[0115] Available solvents include alcohols (methanol, ethanol, isopropanol, butanol, methyl cellusob, ethylsolusob, etc.), ketones (methyl ethyl ketone, methyl butyl ketone, methyl isobutyl ketone, diethyl ketone, dipropyl ketone, cyclohexanone, etc.), acetates (ethyl acetate, propyl acetate, normal butyl acetate, tert-butyl acetate, methyl cellosolve acetate, ethyl cellosolve acetate, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, propylene glycol monopropyl ether acetate, methoxybutyl acetate, methoxypentyl acetate, etc.), hexane-based solvents (hexane, heptane, octane, etc.), benzene-based solvents (benzene, toluene, xylene, etc.), ether-based solvents (diethylene glycol dimethyl ether, diethylene glycol diethyl ether, Diethylene glycol dipropyl ether, diethylene glycol dibutyl ether, propylene glycol monomethyl ether, etc.) can be preferably used. The solvents exemplified above can be used alone or in combination of two or more.

[0116] These solvents are used in an amount of 10 to 80 parts by weight based on 100 parts by weight of the total hard coating composition. If the content of the solvent is less than the above content, the viscosity increases, resulting in poor workability and the thickness of the hard coating layer cannot be reduced, which may result in reduced flexibility. Conversely, if the content exceeds the above range, the desired film thickness cannot be formed, and the coating liquid may flow down during the drying process, contaminating the opposite side of the glass or film and causing stains. Therefore, it is necessary to appropriately adjust the content within the above range.

[0117]

[0118] An optical laminate according to an embodiment of the present invention may be formed by coating a first hard coating composition on glass (110) and performing drying and heat curing steps to form a first hard coating layer (120a, 120b).

[0119] The step of drying the optical laminate can be performed by a heating means such as a hot plate, a hot air circulator, or an infrared furnace, and can be performed at a temperature of 50 to 150°C or 50 to 100°C.

[0120] The step of curing the optical laminate may be formed through a drying and heat curing process at 80°C for 30 minutes. In addition, while in the case of photocurable resins, the curing process is generally performed in two stages after drying, in the case of the thermosetting resin of the present invention, drying and curing can be performed simultaneously.

[0121] The first hard coating layer may be manufactured by a method known in the art. The thickness of the first hard coating layer is not particularly limited. However, when the first hard coating layer exists only on one side of the thin film glass, the thickness of the first hard coating layer may be preferably 20 to 70 μm, and more preferably 40 to 60 μm. When the first hard coating layer exists on both sides of the thin film glass, the thickness of the first hard coating layer may be preferably 10 to 40 μm, and more preferably 25 to 35 μm. When the thickness of the first hard coating layer is outside the above range, there is a problem in that sufficient hardness, adhesion, impact resistance, etc. are not secured. Specifically, when the thickness is thinner than 10 μm, it may be difficult to secure impact resistance, and when the thickness is thicker than 40 μm, it may be difficult to secure bendability.

[0122]

[0123] Second hard coating layer

[0124] When a thermosetting resin that satisfies adhesion to glass and impact resistance is applied to the first hard coating layer, it may be difficult to secure sufficient hardness and scratch resistance to be applied to the surface of a display device, for example, the outermost surface of a flexible display. Therefore, in order to supplement the surface characteristics, such as the hardness of the first hard coating layer, a second hard coating layer including a light-transmitting resin may be formed on the first hard coating layer. For example, as shown in Fig. 1, when a second hard coating layer is laminated on the first hard coating layer, sufficient adhesion can be exhibited because the penetration of a solvent or monomer is easy.

[0125] The second hard coating layer of the present invention is formed from a second hard coating composition including a light-transmitting resin, and the second hard coating composition may further include a dendrimer compound. The dendrimer compound having a hydroxyl terminal group may be commercially available or prepared according to a method known in the art. For example, a dendrimer structure may be formed by condensing a specific polyhydric alcohol as a central skeleton with dimethylolpropionic acid, and then repeatedly condensing the dimethylolpropionic acid as a branched structure to grow into a second or higher generation structure, thereby obtaining a highly branched compound. An example of a commercially available product is Miramer SP1106 from Miwon Specialty Chemical.

[0126] These dendrimer compounds have a structural characteristic in which the terminals of the branched structure are substituted with hydroxyl groups, and the center is completely aliphatic and formed by a tertiary ester bond. Therefore, the terminal hydroxyl groups of the dendrimer compounds are distributed in a larger number within the molecule compared to the molecular weight compared to general monomers, which promotes cationic photocuring and enhances adhesion and cohesion to non-metallic substrates. In addition, the non-reactivity of the aliphatic hydrocarbon as the central skeleton imparts flexibility and improves bendability, making them more desirable when included in a resin used in the manufacture of flexible displays.

[0127] The above dendrimer compound may be included in an amount of 5 to 20 parts by weight based on 100 parts by weight of the total hard coating composition. If the content of the dendrimer compound is less than 5 parts by weight, it is difficult to show improved adhesion, and if it exceeds 20 parts by weight, it may be difficult for curing to occur sufficiently due to the presence of unreacted functional groups due to the steric inhibition effect.

[0128]

[0129] translucent resin

[0130] The second hard coating layer of the present invention may include a light-transmitting resin. The light-transmitting resin may be a photocurable resin, and the photocurable resin may include a photocurable (meth)acrylate oligomer and a photopolymerizable monomer.

[0131] In the present invention, “(meth)acryl-” refers to “methacryl-”, “acryl-” or both.

[0132]

[0133] The photocurable (meth)acrylate oligomer above is typically epoxy (meth)acrylate, urethane (meth)acrylate, etc., with urethane (meth)acrylate being more preferred. Urethane (meth)acrylate can be produced in the presence of a catalyst by combining a polyfunctional (meth)acrylate having a hydroxyl group in the molecule and a compound having an isocyanate group. Specific examples of the (meth)acrylate having a hydroxy group in the molecule include at least one selected from the group consisting of 2-hydroxyethyl (meth)acrylate, 2-hydroxyisopropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, caprolactone ring-opening hydroxyacrylate, pentaerythritol tri / tetra (meth)acrylate, and dipentaerythritol penta / hexa (meth)acrylate. In addition, specific examples of compounds having the above isocyanate group include 1,4-diisocyanatobutane, 1,6-diisocyanatohexane, 1,8-diisocyanatooctane, 1,12-diisocyanatododecane, 1,5-diisocyanato-2-methylpentane, trimethyl-1,6-diisocyanatohexane, 1,3-bis(isocyanatomethyl)cyclohexane, trans-1,4-cyclohexenediisocyanate, 4,4'-methylenebis(cyclohexylisocyanate), isophoronediisocyanate, toluene-2,4-diisocyanate, toluene-2,6-diisocyanate, xylene-1,4-diisocyanate, tetramethylxylene-1,3-diisocyanate, At least one may be selected from the group consisting of 1-chloromethyl-2,4-diisocyanate, 4,4'-methylenebis(2,6-dimethylphenylisocyanate), 4,4'-oxybis(phenylisocyanate), a trifunctional isocyanate derived from hexamethylene diisocyanate, and trimethanepropanol adduct toluene diisocyanate.

[0134] The photopolymerizable monomer may be any monomer used in the art that has an unsaturated group in its molecule, such as a (meth)acryloyl group, a vinyl group, a styryl group, or an allyl group, as a commonly used photocurable functional group. However, among these, a (meth)acryloyl group is more preferable. More specifically, examples thereof include monofunctional and / or polyfunctional (meth)acrylates. These may be used alone or in combination of two or more.

[0135] Specific examples of the monomer having the above (meth)acryloyl group include neopentyl glycol acrylate, 1,6-hexanediol (meth)acrylate, propylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, dipropylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, trimethylolethane tri(meth)acrylate, 1,2,4-cyclohexane tetra(meth)acrylate, pentaglycerol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol tri(meth)acrylate. One member from the group consisting of dipentaerythritol penta(meth)acrylate, dipentaerythritol tetra(meth)acrylate, dipentaerythritol hexa(meth)acrylate, tripentaerythritol tri(meth)acrylate, tripentaerythritol hexatri(meth)acrylate, bis(2-hydroxyethyl)isocyanurate di(meth)acrylate, hydroxyethyl(meth)acrylate, hydroxypropyl(meth)acrylate, hydroxybutyl(meth)acrylate, isooctyl(meth)acrylate, iso-dexyl(meth)acrylate, stearyl(meth)acrylate, tetrahydrofurfuryl(meth)acrylate, phenoxyethyl(meth)acrylate, and isoborneol(meth)acrylate The above can be selected.

[0136] The above-mentioned light-transmitting resin is not particularly limited, but is preferably included in an amount of 10 to 80 parts by weight based on 100 parts by weight of the entire hard coating composition, and more preferably in an amount of 40 to 60 parts by weight. If it is less than 10 parts by weight, it is difficult to achieve sufficient hardness improvement, and if it exceeds 80 parts by weight, there is a problem of severe curling.

[0137]

[0138] Initiator

[0139] The above initiator may be used without limitation as long as it is used in the relevant technical field. For example, one or more selected from the group consisting of hydroxyketones, aminoketones, hydrogen abstraction type photoinitiators, and combinations thereof may be used.

[0140] Specifically, the photoinitiator may be at least one selected from the group consisting of 2-methyl-1-[4-(methylthio)phenyl]2-morpholinepropanone-1, diphenyl ketone, benzyldimethyl ketal, 2-hydroxy-2-methyl-1-phenyl-1-one, 4-hydroxycyclophenyl ketone, 2,2-dimethoxy-2-phenyl-acetophenone, anthraquinone, fluorene, triphenylamine, carbazole, 3-methylacetophenone, 4-xenoloacetophenone, 4,4-dimethoxyacetophenone, 4,4-diaminobenzophenone, 1-hydroxycyclohexylphenyl ketone, benzophenone, diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide, and combinations thereof.

[0141] These photoinitiators are used in an amount of 0.1 to 10 parts by weight, preferably 1 to 5 parts by weight, based on 100 parts by weight of the total hard coating composition. If the content is less than the above range, the curing speed of the composition is slow and under-curing occurs, resulting in poor mechanical properties. Conversely, if the content exceeds the above range, cracks may occur in the coating film due to over-curing.

[0142]

[0143] Additives and solvents

[0144] Additives and solvents that may be further included in the second hard coating composition are the same as those that may be further included in the first hard coating layer described above, and therefore will be omitted.

[0145]

[0146] An optical laminate according to an embodiment of the present invention may be formed by coating a first hard coating composition on glass (110) and performing drying and thermal curing steps to form a first hard coating layer (120a, 120b), and then coating a second hard coating composition on the first hard coating layer (120a) and performing hardening and UV curing steps to form a second hard coating layer (130).

[0147] The step of drying the optical laminate can be performed by a heating means such as a hot plate, a hot air circulator, or an infrared furnace, and can be performed at a temperature of 50 to 150°C or 70 to 130°C.

[0148] The step of curing the optical laminate is 50 to 1000 mJ / cm 2 , preferably 200 to 800 mJ / cm 2 irradiate with active rays such as UV rays. In particular, the step of forming the second hard coating layer (130) is irradiated with 300 to 800 mJ / cm 2 By irradiating with strong UV light, the adhesion between the second hard coating layer and the first hard coating layer can be further strengthened. Light sources used for irradiation include low-pressure mercury lamps, high-pressure mercury lamps, ultra-high-pressure mercury lamps, metal halide lamps, and argon gas lasers, and in some cases, X-rays and electron beams can also be used.

[0149] The thickness of the second hard coating layer is not particularly limited, but may preferably be 10 μm or less, and more preferably 1 to 7 μm. When the thickness is within the above range, it can exhibit better hardness and flexibility, and specifically, when the thickness of the second hard coating layer is less than 1 μm, sufficient hardness and scratch resistance cannot be exhibited, and when it exceeds 10 μm, there is a problem that the bending performance may deteriorate.

[0150]

[0151] <Image display device>

[0152] Embodiments of the present invention provide an image display device including the optical laminate described above.

[0153] For example, the optical laminate described above may be inserted into an image display device and included together with a polarizing layer or a touch sensor layer.

[0154] The above image display device includes various image display devices such as a liquid crystal display device, an electroluminescent display device, a plasma display device, and a field emission display device, and may be a flexible display device having flexibility and bending characteristics.

[0155] In this case, the optical laminate according to embodiments of the present invention can be more effectively applied as a window or window laminate of a flexible display device. Through the interaction of the glass and hard coating layer included in the optical laminate according to embodiments of the present invention, the adhesion and durability of the window can be improved together. Accordingly, for example, the impact resistance and wear resistance of the flexible display device can be improved, and damage such as cracking and peeling can be prevented even when bending.

[0156]

[0157] Hereinafter, specific embodiments of the present invention will be described. However, the present invention is not limited to the embodiments disclosed below, but can be implemented in various different forms. These embodiments are provided only to ensure that the disclosure of the present invention is complete and to fully inform those skilled in the art of the scope of the invention, and the present invention is defined only by the scope of the claims. Unless otherwise specified, "%" and "part" are mass% and mass parts, respectively.

[0158]

[0159] Manufacturing example: Manufacturing of hard coating composition

[0160] Manufacturing Example 1

[0161] A coating composition was prepared by mixing 54.48 parts by weight of a two-component curable acrylic polyol (ASIA Industrial Co., Ltd., SC-330L-4) thermosetting resin, 39.87 parts by weight of methyl ethyl ketone (MEK), 4.17 parts by weight of an epoxy silane coupling agent (Shin-Etsu, KBM-403), 0.55 parts by weight of a silicone-based leveling agent (BYK, BYK-307), and 0.93 parts by weight of a UV absorber (BASF, Tinuvin-928) using a stirrer.

[0162] Manufacturing Example 2

[0163] A coating composition was prepared by mixing 54.65 parts by weight of a two-component curable acrylic polyol (ASIA Industrial Co., Ltd., SC-330L-4) thermosetting resin, 40.00 parts by weight of methyl ethyl ketone (MEK), 4.18 parts by weight of an epoxy silane coupling agent (Shin-Etsu, KBM-403), 0.55 parts by weight of a silicone-based leveling agent (BYK, BYK-307), and 0.62 parts by weight of a UV absorber (BASF, Tinuvin-928) using a stirrer.

[0164] Manufacturing Example 3

[0165] A coating composition was prepared by mixing 54.31 parts by weight of a two-component curable acrylic polyol (Asia Industrial Co., Ltd., SC-330L-4 thermosetting resin), 39.75 parts by weight of methyl ethyl ketone (MEK), 4.16 parts by weight of an epoxy silane coupling agent (Shin-Etsu, KBM-403), 0.55 parts by weight of a silicone-based leveling agent (BYK, BYK-307), and 1.23 parts by weight of a UV absorber (BASF, Tinuvin-928) using a stirrer.

[0166] Manufacturing Example 4

[0167] A coating composition was prepared by mixing 54.48 parts by weight of a two-component curable acrylic polyol (Asia Industrial Co., Ltd., SC-330L-4 thermosetting resin), 39.87 parts by weight of methyl ethyl ketone (MEK), 4.17 parts by weight of an epoxy silane coupling agent (Shin-Etsu, KBM-403), 0.55 parts by weight of a silicone-based leveling agent (BYK, BYK-307), and 0.93 parts by weight of a UV absorber (Daiwa Kasei Co., Ltd., Dainsorb P-7) using a stirrer.

[0168] Manufacturing Example 5

[0169] A coating composition was prepared by mixing 54.99 parts by weight of a two-component curable acrylic polyol (ASIA GONGYU CO., LTD., SC-330L-4) thermosetting resin, 40.24 parts by weight of methyl ethyl ketone (MEK), 4.21 parts by weight of an epoxy silane coupling agent (Shin-Etsu, KBM-403), and 0.56 parts by weight of a silicone-based leveling agent (BYK, BYK-UV3530) using a stirrer.

[0170] Manufacturing Example 6

[0171] A coating composition was prepared by mixing 54.48 parts by weight of a two-component curable acrylic polyol (ASIA Industrial Co., Ltd., SC-330L-4) thermosetting resin, 39.68 parts by weight of methyl ethyl ketone (MEK), 4.17 parts by weight of an epoxy silane coupling agent (Shin-Etsu, KBM-403), 0.55 parts by weight of a silicone-based leveling agent (BYK, BYK-307), 0.93 parts by weight of a UV absorber (BASF, Tinuvin-928), and 0.19 parts by weight of a UV absorber (Orient Chemical, UA-3912) using a stirrer.

[0172] Manufacturing Example 7

[0173] A coating composition was prepared by mixing 5.0 parts by weight of an 18-functional dendrimer acrylate (Miwon Speciality Chemical, Miramer SP1106), 45.02 parts by weight of a 6-functional urethane acrylate (Gongyoung, UA-306H), 3.21 parts by weight of 1-hydroxycyclohexylphenyl ketone, 0.29 parts by weight of a silicone-based leveling agent (BYK, BYK-UV3530), 2.68 parts by weight of a UV absorber (BASF, Tinuvin-928), and 43.80 parts by weight of butyl acetate (BA) using a stirrer.

[0174] Manufacturing Example 8

[0175] A coating composition was prepared by mixing 5.14 parts by weight of an 18-functional dendrimer acrylate (Miwon Speciality Chemical, Miramer SP1106), 46.26 parts by weight of a 6-functional urethane acrylate (Gongyoung, UA-306H), 3.3 parts by weight of 1-hydroxycyclohexylphenyl ketone, 0.3 parts by weight of a silicone-based leveling agent (BYK, BYK-UV3530), and 45 parts by weight of butyl acetate (BA) using a stirrer.

[0176]

[0177] Examples and Comparative Examples: Manufacturing of Optical Laminates

[0178] The hard coating compositions of Manufacturing Examples 1 to 8 were laminated in the order and thickness described in Table 1 below to manufacture optical laminates of Examples and Comparative Examples.

[0179] Example 1

[0180] The coating composition of the above manufacturing example 1 was coated on a thin film glass (50 μm) to a thickness of 40 μm after curing, and heat curing was performed at a temperature of 80°C for 30 minutes, and then corona treatment was performed on the upper part of the coating surface, and the coating solution of manufacturing example 8 was cured, and a 2-layer coating was performed on the coating surface to a thickness of 5 μm, and the solvent was dried and UV accumulated light intensity was 600 mj / cm in a nitrogen atmosphere. 2 An optical laminate is manufactured by investigating the method.

[0181] Example 2

[0182] The coating composition of the above Manufacturing Example 2 was coated on a thin film glass (50 μm) to a thickness of 60 μm after curing, and heat curing was performed at a temperature of 80°C for 30 minutes, and then corona treatment was performed on the upper part of the coating surface, and the coating solution of Manufacturing Example 8 was cured and 2 layers were coated on the coating surface to a thickness of 5 μm, and the solvent was dried and UV accumulated light intensity was 600 mj / cm in a nitrogen atmosphere. 2 An optical laminate is manufactured by investigating the method.

[0183] Example 3

[0184] The coating composition of the above Manufacturing Example 3 was first coated on a thin film glass (50 μm) to a thickness of 30 μm after curing, and then heat-cured at a temperature of 80°C for 30 minutes, and then the coating composition of the same Manufacturing Example 3 was additionally coated on the opposite side of the coating surface of the thin film glass (50 μm) to a thickness of 30 μm after curing, and then heat-cured at a temperature of 80°C for 30 minutes, and then corona treatment was performed on the upper part of the coating surface, and the coating solution of Manufacturing Example 8 was cured and then 2-Layer coated to a thickness of 5 μm, and then solvent-dried and UV-integrated light intensity of 600 mj / cm was applied under a nitrogen atmosphere. 2An optical laminate is manufactured by investigating the method.

[0185] Example 4

[0186] The coating composition of the above Manufacturing Example 4 was coated on a thin film glass (50 μm) to a thickness of 40 μm after curing, and heat curing was performed at a temperature of 80°C for 30 minutes, and then corona treatment was performed on the upper part of the coating surface, and the coating solution of Manufacturing Example 8 was cured and 2 layers were coated on the coating surface to a thickness of 5 μm, and the solvent was dried and UV accumulated light intensity was 600 mj / cm in a nitrogen atmosphere. 2 An optical laminate is manufactured by investigating the method.

[0187] Example 5

[0188] The method described in Example 4 was similar to that described in Example 4, except that the coating composition was applied thickly to the curved portion (50 μm) of the thin film glass made using the technique known in prior art patent No. 10-2272926 and thinly to the flat portion, so that the optical laminate having the hard coating layer applied had an overall flat surface.

[0189] Comparative Example 1

[0190] The coating composition of the above manufacturing example 8 was coated on a thin film glass (50 μm) to a thickness of 30 μm after curing, and the solvent was dried and UV accumulated light intensity was 600 mj / cm in a nitrogen atmosphere. 2 An optical laminate is manufactured by investigating the method.

[0191] Comparative Example 2

[0192] The coating composition of the above Manufacturing Example 5 was coated on a thin film glass (50 μm) to a thickness of 40 μm after curing, and heat curing was performed at a temperature of 80°C for 30 minutes, and then corona treatment was performed on the upper part of the coating surface, and the coating solution of Manufacturing Example 8 was cured and a 2-layer coating was performed on the coating surface to a thickness of 5 μm, and the solvent was dried and UV accumulated light intensity was 600 mj / cm in a nitrogen atmosphere. 2 An optical laminate is manufactured by investigating the method.

[0193] Comparative Example 3

[0194] The coating composition of the above manufacturing example 7 was coated on a thin film glass (50 ㎛) to a thickness of 30 ㎛ after curing, and the solvent was dried and UV accumulated light intensity was 600 mj / cm in a nitrogen atmosphere. 2 An optical laminate is manufactured by investigating the method.

[0195] Comparative Example 4

[0196] The coating composition of the above Manufacturing Example 6 was coated on a thin film glass (50 μm) to a thickness of 40 μm after curing, and heat curing was performed at a temperature of 80°C for 30 minutes, and then corona treatment was performed on the upper part of the coating surface, and the coating solution of Manufacturing Example 8 was cured and a 2-layer coating was performed on the coating surface to a thickness of 5 μm, and the solvent was dried and UV accumulated light intensity was 600 mj / cm in a nitrogen atmosphere. 2 An optical laminate is manufactured by investigating the method.

[0197] Second hard coating layer First hard coating layer (120a) Thin film glass First hard coating layer (120b) Example 1 Manufacturing example 8 (5㎛) Manufacturing example 1 (40㎛) 50㎛ - Example 2 Manufacturing example 8 (5㎛) Manufacturing example 2 (60㎛) 50㎛ - Example 3 Manufacturing example 8 (5㎛) Manufacturing example 3 (30㎛) 50㎛ Manufacturing example 3 (30㎛) Example 4 Manufacturing example 8 (5㎛) Manufacturing example 4 (40㎛) 50㎛ - Example 5 Manufacturing example 8 (5㎛) Manufacturing example 4 (40㎛) Flat part 100㎛, curved part 50㎛-Comparative Example 1 Manufacturing Example 8 (30㎛)-50㎛-Comparative Example 2 Manufacturing Example 8 (5㎛) Manufacturing Example 5 (40㎛) 50㎛-Comparative Example 3 Manufacturing Example 7 (30㎛)-50㎛-Comparative Example 4 Manufacturing Example 8 (5㎛) Manufacturing Example 6 (40㎛) 50㎛-

[0198] (Unit: ㎛)

[0199]

[0200] Experimental example

[0201] The physical properties of the optical laminates manufactured in Examples 1 to 5 and Comparative Examples 1 to 4 were measured using the following methods, and the results are shown in Table 2.

[0202]

[0203] (1) Evaluation of total light transmittance (Tt) and haze

[0204] The optical laminates of the above examples and comparative examples were measured for total light transmittance and haze according to JIS 7136 using a haze meter (HM-150, Murakami).

[0205]

[0206] (2) Spectral transmittance evaluation

[0207] The optical laminates of the above examples and comparative examples are measured for spectral transmittance at 380 nm and spectral transmittance at a wavelength of 440 nm using UV-2600 (Shimadzu Corporation) equipment.

[0208]

[0209] (3) Adhesion evaluation

[0210] After the optical laminates of the above examples and comparative examples were bonded to glass using a transparent adhesive so that the hard coating surface was facing upward, scratches were made on the hard coating surface in the form of 100 squares in length and width at 1 mm intervals using a cutter knife, and an adhesion test was performed three times using a niche tape.

[0211] <Evaluation Criteria>

[0212] 5B: Unpeeled

[0213] 4B: Less than 5% peeling

[0214] 3B: 5% or more but less than 15% peeling

[0215] 2B: 15% to 35% peeling

[0216] 1B: 35% to 65% peeling

[0217] 0B: 65% or more peeling

[0218]

[0219] (4) Scratch resistance evaluation

[0220] After fixing the optical laminates manufactured in the above examples and comparative examples so that the coating surface was facing upward, a scratch resistance test was performed using a Steel Wool Scratch Tester (Samjitech, Model: SJTR-053) according to the following method. After mounting steel wool (Bonstar #0000) on each steel wool stacking section, the surface was visually checked for discoloration and scratches after 10 reciprocations under a load of 2 kg.

[0221]

[0222] (5) Impact resistance evaluation

[0223] After fixing the optical laminate manufactured in the above examples and comparative examples with the coating surface facing upward, the impact resistance was evaluated by measuring the height at which breakage occurred due to impact when dropped from a certain height using a 0.3ø pen.

[0224] <Evaluation Criteria>

[0225] ○: 3cm or more

[0226] △: 2cm or more ~ ​​less than 3cm

[0227] X: less than 2cm

[0228]

[0229] (6) Pencil hardness evaluation

[0230] After fixing the coated surface upward, the pencil hardness was measured under a load of 1 kg. The test was performed 5 times with a 1 cm length pencil of the same hardness, and the hardness that was OK 4 or more times was designated as the pencil hardness.

[0231]

[0232] (7) Flexibility evaluation

[0233] When the optical laminate manufactured above was folded so that the second hard coating layers were in contact with each other, a folding test was performed by repeating the folding test 200,000 times so that the radius of curvature of the folded portion was 5 mm.

[0234] <Evaluation Criteria>

[0235] ○: No cracks or breaks

[0236] X: Cracks or fractures occur

[0237] TtHaze380nm T440nm T Pencil Hardness Scratch resistance Adhesion Impact resistance Flexibility Example 190.30.42.8289.642HO5B△O Example 290.40.31.1887.572HO5BOO Example 391.80.12.3590.722HO5BOO Example 490.40.40.2582.32HO5BOO Example 590.30.40.2382.12HO5BOO Comparative Example 190.60.180.2388.772HO0BXX Comparative Example 2910.487.0189.782HO5B△O Comparative Example 390.60.20.1287.72H or lessX0BXX Comparative Example 490.50.20.0171.252HO5B△O

[0238]

[0239] Referring to the experimental data in Table 2 above, in the case of Examples 1 to 5 in which the optical laminate including the first hard coating layer and the second hard coating layer according to the present invention was applied, the total light transmittance, haze, 380 nm ultraviolet spectral transmittance of less than 3%, 440 nm wavelength spectral transmittance of 80% or more, hardness, scratch resistance, adhesion, impact resistance, and bending properties were all excellently satisfied.

[0240] On the other hand, in the case of the optical laminates of Comparative Examples 1 and 3 in which the hard coating layer was formed as a single layer, the optical laminate of Comparative Example 2 in which the first hard coating layer did not include a UV absorber, and the optical laminate of Comparative Example 4 in which the first hard coating layer included a UV absorber other than benzophenone and / or benzotriazole, some of the performances among total light transmittance, haze, 380 nm wavelength spectral transmittance, 440 nm wavelength spectral transmittance, hardness, scratch resistance, adhesion, impact resistance, and bendability did not reach the level of the present invention, and thus did not exhibit physical properties suitable for an optical laminate for a flexible display.

[0241] In particular, in the case of Comparative Example 1 in which the first hard coating layer was not laminated, the impact resistance was X even though it was manufactured to 30 μm, and since the thickness of the hard coating layer manufactured using the second hard coating composition exceeded 10 μm, the bendability and adhesion evaluations were X, and since the UV absorber was not included, it was very poor in terms of spectral transmittance at a wavelength of 380 nm.

[0242] In addition, in the case of Comparative Example 2, in which a first hard coating layer without a UV absorber was laminated, the UV blocking property was not sufficiently secured as more than 80% of the UV light was transmitted in the 380 nm UV transmittance evaluation, and the impact resistance was also poor.

[0243] Furthermore, in the case of Comparative Example 3, the optical laminate including the hard coating layer manufactured with the second hard coating composition including a UV absorber not only had poor impact resistance, but also the second hard coating composition including both a photocurable resin and a UV absorber was not sufficiently cured, so the overall physical properties in terms of hardness, scratch resistance, adhesion, impact resistance, and flexibility were all very poor.

[0244] In addition, in the case of Comparative Example 4, the spectral transmittance of ultraviolet rays with a wavelength of 380 nm was low as the first hard coating layer was manufactured by including both a benzotriazole-based UV absorber and an indole-based UV absorber, but since the spectral transmittance at a wavelength of 440 nm was significantly lower than 80%, the transmittance of visible light was poor, making it unsuitable in terms of display clarity.

[0245]

[0246]

[0247] The optical laminate according to the present invention and the image display device including the same include a hard coating layer including a UV absorber, thereby having excellent blocking of ultraviolet rays with a wavelength of 300 to 380 nm, and excellent spectral transmittance at a wavelength of 440 nm, so that sufficient visible light is transmitted while excellently blocking ultraviolet rays, and the hardness, scratch resistance, and impact resistance of the display are improved, and sufficient total light transmittance and haze that does not affect visibility are possible.

Claims

1. Thin film glass; A first hard coating layer formed on one or both sides of the thin film glass; and An optical laminate comprising a second hard coating layer formed on a first hard coating layer; The above first hard coating layer includes a thermosetting resin and a UV absorber, An optical laminate, characterized in that the second hard coating layer comprises a light-transmitting resin.

2. In claim 1, An optical laminate, wherein the above UV absorber is at least one selected from among benzophenone-based and benzotriazole-based UV absorbers.

3. In claim 1, An optical laminate, wherein the thermosetting resin contains an alkoxysilane group and an epoxy group.

4. In claim 1, An optical laminate wherein the thermosetting resin is an acrylic polyol-based resin.

5. In claim 1, The first hard coating layer is formed from a first hard coating composition, An optical laminate in which the first hard coating composition contains 0.5 to 2.0 parts by weight of a UV absorber relative to 100 parts by weight of the total composition.

6. In claim 1, An optical laminate, wherein the above-mentioned transparent resin is manufactured by including at least one selected from epoxy (meth)acrylate, urethane (meth)acrylate, and ester (meth)acrylate.

7. In claim 1, The second hard coating layer is formed from a second hard coating composition, An optical laminate wherein the second hard coating composition comprises a dendrimer compound.

8. In claim 1, An optical laminate characterized in that the spectral transmittance is 5% or less in the wavelength range of 300 nm to 380 nm and the spectral transmittance is 80% or more in the wavelength range of 440 nm.

9. In claim 1, An optical laminate wherein the thickness of the above thin film glass is 10 to 100 μm.

10. In claim 1, An optical laminate in which the first hard coating layer exists only on one side of the thin film glass, and the thickness of the first hard coating layer is 20 to 70 μm.

11. In claim 1, An optical laminate in which the first hard coating layer exists on both sides of the thin film glass, and the thickness of each of the first hard coating layers is 10 to 40 μm.

12. In claim 1, An optical laminate, wherein the thickness of the second hard coating layer is 10㎛ or less.

13. In claim 1, An optical laminate, wherein the thin film glass includes a flat portion and a curved portion.

14. In claim 5, The above first hard coating composition further comprises an epoxy silane coupling agent, An optical laminate, wherein the epoxy silane coupling agent comprises at least one selected from 3-glycidoxypropyldimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 8-glycidoxyoctyltrimethoxysilane, and 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane.

15. In claim 1, An optical laminate, characterized in that the thin film glass, the first hard coating layer, and the second hard coating layer are formed in direct contact with each other without including a separate layer.

16. In claim 1, An optical laminate for application to flexible displays.

17. An image display device comprising an optical laminate according to any one of claims 1 to 16.

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