Laminated film and image display device containing the same

Abstract

The present invention relates to a laminated film comprising a hard coating layer and a substrate, wherein the hard coating layer comprises a near-ultraviolet absorber and an ultraviolet light enhancer / decreaser, and the substrate comprises an ultraviolet blocking additive, and to an image display device comprising the same.

Description

Technical Field

[0001] The present invention relates to a laminated film and an image display device including the same.

Background Art

[0002] Recently, organic light emitting diodes (OLEDs) have been widely used as display materials in various smart devices characterized by portability, ranging from smart phones, tablets to various wearable devices.

[0003] Conventional OLED devices used a polarizing film to prevent external light reflection. However, recently, the number of OLED devices that do not use a polarizing film has been increasing in order to improve brightness or provide transparent OLEDs. Such OLED devices without the application of a polarizing film have the disadvantage that the deterioration of the OLED element occurs due to ultraviolet rays and near-ultraviolet rays, etc., resulting in a short display life.

[0004] Korean Patent Publication No. 10-2000-0042841 provides an agricultural film composition for blocking near-ultraviolet rays. However, these are methods in which ultraviolet additives, etc. are added into the film, and there is a problem that the degree of curing is reduced by the ultraviolet additives during manufacturing in the case of a film cured using ultraviolet rays.

[0005] Therefore, there is a need for the development of a laminated film that can shield near-ultraviolet rays to prevent the deterioration of the OLED element, maintain the ultraviolet curing efficiency of the hard coating layer, and ensure sufficient substrate adhesion, and an image display device including the same.

Summary of the Invention

Problems to be Solved by the Invention

[0006] The present invention aims to provide a laminated film that solves the aforementioned problems by maintaining transparency in the visible light region, efficiently blocking near-ultraviolet light to prevent degradation of OLED elements, maintaining the ultraviolet curing efficiency of the hard coating layer, and ensuring sufficient adhesion to the substrate.

[0007] Furthermore, the present invention aims to provide a window comprising the laminated film and having excellent light resistance, and an image display device including the same.

[0008] However, the problems that this invention aims to solve are not limited to those mentioned above, and other problems not mentioned can be clearly understood by an ordinary person of the art from the following description. [Means for solving the problem]

[0009] The present invention relates to a laminated film comprising a hard coating layer and a substrate, wherein the hard coating layer comprises a near-ultraviolet absorber and an ultraviolet light enhancer / decreaser, and the substrate is an ultraviolet-blocking substrate.

[0010] In the present invention, the transmittance of the substrate at a wavelength of 380 nm may be 10% or less.

[0011] In the present invention, the substrate may contain an ultraviolet-blocking additive.

[0012] In the present invention, the substrate may be one or more selected from polyester films, cellulose films, and polyimide films.

[0013] In the present invention, the maximum absorption wavelength of the near-ultraviolet absorber may be between 390 nm and 430 nm.

[0014] The present invention may also be characterized in that the near-ultraviolet absorber is a cyanine-based compound.

[0015] In the present invention, the maximum absorption wavelength of the ultraviolet light adjusting agent may be from 350 nm to 400 nm.

[0016] In the present invention, the ultraviolet light adjusting agent may be an oxazole-based compound.

[0017] In the present invention, the hard coating layer may be produced from a hard coating composition, and the hard coating composition may contain a near-ultraviolet absorber, an ultraviolet light adjusting agent, a photocurable resin, and a solvent.

[0018] In the present invention, the near-ultraviolet absorber may be contained in an amount of 0.1 to 1 part by weight based on the total weight of the hard coating composition.

[0019] In the present invention, the ultraviolet light adjusting agent may be contained in an amount of 0.1 to 2 parts by weight based on the total weight of the hard coating composition.

[0020] In the present invention, the total light transmittance of the laminated film may be 85% or more. More preferably, the total light transmittance of the laminated film may be 90% or more.

[0021] In the present invention, the haze of the laminated film may be 2% or less.

[0022] In the present invention, the transmittance of the laminated film at a wavelength of 360 nm may be 5% or less.

[0023] In the present invention, the transmittance of the laminated film at a wavelength of 380 nm may be 5% or less.

[0024] In the present invention, the transmittance of the laminated film at a wavelength of 400 nm may be 10% or less.

[0025] The present invention may also relate to an image display device including the laminated film.

Advantages of the Invention

[0026] According to the laminated film of the present invention, since the transmittance in the ultraviolet and / or near-ultraviolet region is low, the ultraviolet and / or near-ultraviolet rays can be effectively blocked. Thereby, the deterioration of the OLED element can be prevented, and the problem of shortening the life of the display can be improved.

[0027] Also, according to the laminated film of the present invention, since the haze value is low, it exhibits high transparency, blocks ultraviolet rays including an ultraviolet light modifier, and can maintain the ultraviolet curing efficiency of the hard coating layer. Thereby, sufficient adhesion to the substrate can be ensured, so that a laminated film having excellent physical and / or optical properties and an image display device including the same can be provided.

Brief Description of the Drawings

[0028] [Figure 1] FIG. 1 is a diagram showing a laminated structure of a laminated film in which a near-ultraviolet blocking hard coating layer 100 and an ultraviolet blocking substrate 200 are sequentially laminated according to an embodiment of the present invention.

Embodiments for Carrying Out the Invention

[0029] The present invention relates to a laminated film including a hard coating layer and a substrate, the hard coating layer including a near-ultraviolet absorber and an ultraviolet light modifier, and the substrate being an ultraviolet blocking substrate, and an image display device including the same.

[0030] According to an embodiment of the present invention, the laminated film may be one in which a hard coating layer including a near-ultraviolet absorber and an ultraviolet light modifier and an ultraviolet blocking substrate are sequentially laminated.

[0031] According to one embodiment of the present invention, the laminated film may be characterized by having a low transmittance of 10% or less, preferably 9% or less, and more preferably 7% or less, at wavelengths of 360 nm and / or 380 nm and / or 400 nm. Most preferably, the transmittance at wavelengths of 360 nm, 380 nm, and 400 nm may be 5%, 5%, and 10% or less, respectively. In this case, ultraviolet and / or near-ultraviolet light can be effectively shielded, thereby preventing degradation of the OLED element and improving the problem of shortened display lifespan.

[0032] According to one embodiment of the present invention, the hard coating layer contains an ultraviolet light enhancer / decreaser, which can block ultraviolet light and maintain the ultraviolet curing efficiency of the hard coating layer, and can ensure sufficient adhesion to the substrate, thereby providing a laminated film suitable for protecting OLED elements.

[0033] The embodiments of the present invention will be described more specifically below with reference to the drawings. However, the following drawings attached to this specification illustrate preferred embodiments of the present invention and, together with the content of the invention described above, serve to further illustrate the technical concept of the present invention. Therefore, the present invention should not be interpreted as being limited only to the matters described in such drawings.

[0034] The terms used herein are for illustrative purposes only and are not intended to limit the invention.

[0035] As used herein, "comprises" and / or "comprising" are used in a manner that does not exclude the presence or addition of one or more other components, steps, operations, and / or elements other than those mentioned. Reference numerals identical throughout the specification refer to the same component.

[0036] Spatially relative terms such as "down," "bottom," "lower part," "up," "upper part," and "upper part" can be used to easily describe the correlation between one element or component and another element or component, as shown in the drawing. Spatially relative terms should be understood as terms that include not only the directions shown in the drawing, but also the different directions of elements when in use or operation. For example, when overturning an element shown in a drawing, an element described as "down" or "lower part" of another element may be placed "up" of the other element. Therefore, the exemplary term "down" can include both the down and up directions. Elements can be oriented in other directions, and thus spatially relative terms can be interpreted by orientation.

[0037] In this invention, "transparent" means that the transmittance of visible light is 70% or more, preferably 80% or more.

[0038] In this invention, "ultraviolet light" refers to wavelengths from 100 nm to 390 nm, and "near-ultraviolet light" refers to wavelengths from 390 nm to 430 nm.

[0039] In this invention, "shielding" and "blocking" are used substantially without distinction, both meaning to prevent the effects of light rays such as ultraviolet or near-ultraviolet light.

[0040] <Laminated film> Referring to Figure 1, a laminated film according to one embodiment of the present invention may include a hard coating layer 100 and a substrate 200.

[0041] Hard coating layer 100 The hard coating layer of the present invention is a layer that blocks near-ultraviolet light and exhibits high adhesion due to its excellent degree of curing.

[0042] Specifically, the hard coating layer of the present invention is characterized by containing a near-ultraviolet absorber and an ultraviolet light modifier, and contains an ultraviolet light modifier. This allows for shielding from ultraviolet rays while maintaining the ultraviolet curing efficiency of the hard coating layer, ensuring sufficient adhesion to the substrate, and thus providing a laminated film suitable for protecting OLED elements.

[0043] A hard coating layer 100 according to one embodiment of the present invention may be manufactured from a hard coating composition. Specifically, the hard coating composition may contain one or more selected from the group consisting of near-ultraviolet absorbers, ultraviolet light enhancers / decreasers, photocurable resins, and solvents, and may further contain additives. Furthermore, other known components included in hard coating compositions of the art may be further included without limitation, as long as they do not affect the purpose and effect of the present invention.

[0044] The hard coating layer 100 is formed on a substrate 200, which will be described later. The hard coating layer 100 according to one embodiment of the present invention may be manufactured by applying a hard coating composition to the substrate 200 and then curing it with light or heat. The hard coating composition according to one embodiment of the present invention may be a hard coating composition that has excellent adhesion to the substrate 200 and can improve ultraviolet and / or near-ultraviolet shielding properties.

[0045] Near-ultraviolet absorber The near-ultraviolet absorber used in forming a hard coating layer according to one embodiment of the present invention is a component distinct from the ultraviolet stabilizer described later, and may transmit ultraviolet light and selectively absorb near-ultraviolet light. The near-ultraviolet absorber according to one embodiment of the present invention may have a maximum absorption wavelength of 390 nm to 430 nm, preferably 395 nm to 425 nm, and more preferably 400 nm to 420 nm. The near-ultraviolet absorber may be one or more selected from, for example, cyanine compounds, benzophenone compounds, benzotriazole compounds, and triazine compounds, and is preferably a cyanine compound in order to effectively absorb near-ultraviolet light in the 390 nm to 430 nm region.

[0046] The near-ultraviolet absorber may be included in an amount of 0.01 to 5 parts by weight, preferably 0.1 to 1 part by weight, and more preferably 0.3 to 0.7 parts by weight, relative to the total weight of the hard coating composition.

[0047] UV light enhancer / decreaser The ultraviolet light modifier used in forming a hard coating layer according to one embodiment of the present invention absorbs ultraviolet light to block it, and also functions to promote the hardening of the hard coating layer by transferring energy (absorbing and then releasing) to the initiator contained in the hard coating composition, which will be described later, through a photochemical reaction. The ultraviolet light modifier absorbs light in the ultraviolet region through this series of photochemical reactions to maintain low transmittance, and simultaneously induces the initiation reaction of the initiator that causes the crosslinking reaction of the ultraviolet-curable material. When the laminated film according to one embodiment of the present invention contains the ultraviolet light modifier, the adhesion to the substrate can be improved.

[0048] The ultraviolet light enhancer / reduction agent according to one embodiment of the present invention may have a maximum absorption wavelength of 350 nm to 400 nm, preferably 355 nm to 395 nm, and more preferably 360 nm to 390 nm.

[0049] As the UV light increasing / decreasing agent described above, one or more may be selected from, for example, oxazole, anthraquinone, naphthoquinone, quinone, thioxanthone, acridone, benzoyl diphenylphosphine oxide, 1,2-diketone, phenothiazine, ketocoumarin, fluorene, naphthiazoline, biacetyl, benzyl and their derivatives, perylene, and substituted / unsubstituted anthracenes, and an oxazole compound is preferred from the viewpoint of being able to effectively absorb ultraviolet light in the 350 nm to 400 nm region.

[0050] The ultraviolet light enhancer / decreaser may be included in an amount of 0.01 to 5 parts by weight, preferably 0.1 to 2 parts by weight, and more preferably 0.5 to 1.5 parts by weight, relative to the total weight of the hard coating composition.

[0051] photocurable resin The photocurable resin used to form the hard coating layer of the present invention contains a photopolymerizable functional group and may be a photopolymerizable monomer, a photopolymerizable oligomer, or, for example, a photoradical polymerizable compound.

[0052] The photopolymerizable monomers are commonly used photocurable functional groups, and can be any monomer used in the art that has an unsaturated group in the molecule, such as a (meth)acryloyl group, vinyl group, styryl group, or allyl group, without limiting themselves to any monomers used in the art. More specifically, examples include monofunctional and / or polyfunctional (meth)acrylates. These may be used individually or in combination of two or more.

[0053] In this invention, "(meth)acrylic-" refers to "methacrylate-", "acrylic-", or both.

[0054] Specific examples of (meth)acrylate monomers include (meth)acrylic acid esters such as trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, glycerol tri(meth)acrylate, tris(2-hydroxyethyl)isocyanurate tri(meth)acrylate, ethylene glycol di(meth)acrylate, propylene glycol (meth)acrylate, 1,3-butanediol di(meth)acrylate, and 1,4-butanediol di(meth)acrylate. )Acrylate, 1,6-Hexanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, dipropylene glycol di(meth)acrylate, bis(2-hydroxyethyl)isocyanurate di(meth)acrylate, poly(meth)acrylate with ethylene oxide or propylene oxide added to the (meth)acrylic acid ester; 1 to 3 (meth)acrylates in the molecule Examples include oligoester (meth)acrylates having a royl group, oligoether (meth)acrylates, oligourethane (meth)acrylates, and oligoepoxy (meth)acrylates; hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, hydroxybutyl (meth)acrylate, and products of the (meth)acrylates with the addition of ethylene oxide or propylene oxide; and mono(meth)acrylates, such as monomers having three or fewer (meth)acryloyl groups, including iso-octyl (meth)acrylate, iso-decyl (meth)acrylate, stearyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, and phenoxyethyl (meth)acrylate, as well as dipentaerythritol hexa(meth)acrylate, dipentaerythritol hydroxypenta(meth)acrylate, pentaerythritol tetra(meth)acrylate, and ditrimethylolpropanetetra(meth)acrylate. These may be used individually or in combination of two or more.

[0055] The photopolymerizable oligomer can be one or more selected from the group consisting of epoxy (meth)acrylate, urethane (meth)acrylate, and polyester (meth)acrylate, for example. Specifically, a mixture of urethane (meth)acrylate and polyester (meth)acrylate can be used, or a mixture of two types of polyester (meth)acrylate can be used. It is preferable to include a urethane (meth)acrylate oligomer in order to improve the scratch resistance and hardness of the cured product and to increase the elastic modulus of the hard coating layer.

[0056] The aforementioned urethane (meth)acrylate can be produced by reacting a polyfunctional (meth)acrylate having a hydroxyl group in its molecule with a compound having an isocyanate group in the presence of a catalyst using a method known to the art.

[0057] Specific examples of polyfunctional (meth)acrylates having a hydroxyl group in the molecule may be one or more selected from the group consisting of 2-hydroxyethyl (meth)acrylate, 2-hydroxyisopropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, caprolactone ring-opened hydroxyacrylate, pentaerythritol tri / tetra(meth)acrylate mixtures, and dipentaerythritol penta / hexa(meth)acrylate mixtures.

[0058] Furthermore, specific examples of compounds containing an 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-cyclohexene diisocyanate, 4,4'-methylenebis(cyclohexyl isocyanate), isophorone diisocyanate, and toluene-2,4- It may be one or more selected from the group consisting of diisocyanates, toluene-2,6-diisocyanate, xylene-1,4-diisocyanate, tetramethylxylene-1,3-diisocyanate, 1-chloromethyl-2,4-diisocyanate, 4,4'-methylenebis(2,6-dimethylphenyl isocyanate), 4,4'-oxybis(phenyl isocyanate), trifunctional isocyanates derived from hexamethylene diisocyanate, and trimethanepropanol adductotoluene diisocyanate.

[0059] More specifically, the urethane (meth)acrylate oligomer may be a compound containing two or more substituents represented by the following chemical formula 1 and two or more (meth)acryloyl groups within its molecule. [Chemical formula 1] *-OC(=O)NH-*

[0060] The urethane (meth)acrylate oligomer may be produced by reacting 1 mole of diisocyanate represented by the following chemical formula 2 with 2 moles of an active hydrogen-containing polymerizable unsaturated compound. [Chemical formula 2] R1-OC(=O)NH-R3-NHC(=O)O-R2 In the formula, R1 and R2 are substituents containing a (meth)acryloyl group derived from an active hydrogen-containing polymerizable unsaturated compound, and R3 is a divalent substituent derived from a diisocyanate.

[0061] Specific examples of urethane (meth)acrylate oligomers include the products of the reactions of 2-hydroxyethyl (meth)acrylate and 2,4-tolylene diisocyanate, 2-hydroxyethyl (meth)acrylate and isophorone diisocyanate, 2-hydroxybutyl (meth)acrylate and 2,4-tolylene diisocyanate, 2-hydroxybutyl (meth)acrylate and isophorone diisocyanate, pentaerythritol tri(meth)acrylate and 2,4-toluene diisocyanate, pentaerythritol tri(meth)acrylate and isophorone diisocyanate, pentaerythritol tri(meth)acrylate and dicyclohexylmethane diisocyanate, dipentaerythritol penta(meth)acrylate and isophorone diisocyanate, and dipentaerythritol penta(meth)acrylate and dicyclohexylmethane diisocyanate.

[0062] Polyester (meth)acrylate can be produced by reacting a polyester polyol with acrylic acid using methods known in the industry.

[0063] The polyester (meth)acrylate may be selected from, but is not limited to, one or more of the group consisting of, for example, polyester acrylate, polyester diacrylate, polyester tetraacrylate, polyester hexaacrylate, polyester pentaerythritol triacrylate, polyester pentaerythritol tetraacrylate, and polyester pentaerythritol hexaacrylate.

[0064] Photopolymerizable monomers and photopolymerizable oligomers can be used individually or in combination. When photopolymerizable monomers and photopolymerizable oligomers are used in combination, the workability and compatibility of the hard coating composition can be increased.

[0065] The content ratio of the photopolymerizable monomer to the photopolymerizable oligomer is not particularly limited and may be appropriately selected considering the storage modulus, shrinkage force, and workability of the hard coating layer. For example, the content ratio of the photopolymerizable oligomer to the photopolymerizable monomer may be between 1:10 and 10:1. If the content ratio of the photopolymerizable oligomer to the photopolymerizable monomer falls outside the above range, the storage modulus of the hard coating layer may decrease, or the shrinkage force may increase, leading to a decrease in hardness and flexibility, which may cause curling.

[0066] The content of the photocurable resin is not particularly limited, but for example, it may be included in an amount of 1 to 80 parts by weight, preferably 1 to 50 parts by weight, per 100 parts by weight of the total hard coating composition. If the amount of the photocurable resin is less than 1 part by weight, the elastic modulus of the hard coating layer will decrease, and cracks may easily occur in the hard coating layer when bent. If it exceeds 80 parts by weight, the viscosity will increase, reducing the applicability and potentially leading to insufficient surface leveling and problems with apparent properties.

[0067] Initiator The initiator can be used without limitation as long as it is used in the art. For example, one or more selected from the group consisting of hydroxyketones, aminoketones, hydrogen recapture photoinitiators, and combinations thereof can be used.

[0068] Specifically, the photoinitiator can be one or more 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-phenylacetophenone, anthraquinone, fluorene, triphenylamine, cabazole, 3-methylacetophenone, 4-chloroacetophenone, 4,4-dimethoxyacetophenone, 4,4-diaminobenzophenone, 1-hydroxycyclohexylphenyl ketone, benzophenone, diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide, and combinations thereof.

[0069] Such photoinitiators are used in an amount of 0.1 to 10 parts by weight, preferably 0.3 to 5 parts by weight, per 100 parts by weight of the total hard coating composition. If the content is less than the above range, the curing rate of the composition will be delayed, resulting in uncured material and poor mechanical properties. Conversely, if the amount exceeds the above range, overcuring may occur, potentially causing cracks in the coating film.

[0070] solvent The solvent can dissolve or disperse the aforementioned composition and is not limited to any solvent known as a solvent for coating layer forming compositions in the art.

[0071] Usable solvents include alcohol-based solvents (methanol, ethanol, isopropanol, butanol, methyl cellosolve, ethyl cellosolve, etc.), ketone-based solvents (methyl ethyl ketone, methyl butyl ketone, methyl isobutyl ketone, diethyl ketone, dipropyl ketone, cyclohexanone, etc.), and acetate-based solvents (ethyl acetate, propyl acetate, normal butyl acetate, tert-butyl acetate, methyl cellosolve acetate, ethyl cellosolve acetate, propylene glycol monomethyl ethyl acetate, propylene Preferably, solvents such as diethylene glycol monoethyl ethyl acetate, propylene glycol monopropyl ethyl acetate, methoxybutyl acetate, methoxypentyl acetate, etc., hexane-based solvents (hexane, heptane, octane, etc.), benzene-based solvents (benzene, toluene, xylene, etc.), and ether-based solvents (diethylene glycol dimethyl ethyl ethyl ethyl ethyl ethyl ethyl ethyl ethyl ethyl ethyl ethyl ethyl ethyl ethyl ethyl ethyl ethyl ethyl ethyl ethyl ethyl ethyl ethyl ethyl ethyl ethyl ethyl ethyl ethyl ethyl ethyl ethyl ethyl ethyl ethyl propyl glycol monomethyl ether, etc.) may be used. Each of the exemplified solvents can be used alone or in combination of two or more.

[0072] Such a solvent can be used in amounts of 10 to 95 parts by weight per 100 parts by weight of the total hard coating composition, and may be included as a remainder after removing other components from the composition. If the solvent content is less than the aforementioned amount, the viscosity will be high and workability will be poor, and the sweeping of the base film will not be sufficiently advanced. Conversely, if it exceeds the aforementioned range, the drying process will take a long time, resulting in poor economic efficiency. Therefore, it should be used appropriately within the aforementioned range.

[0073] additives Furthermore, the hard coating composition used to form the hard coating layer according to the present invention may further contain, in addition to the components described above, one or more additives selected from the group consisting of leveling agents, ultraviolet stabilizers, and heat stabilizers, and may further contain additives commonly used in the art to which the present invention belongs. Moreover, the content thereof can be adjusted in various ways within a range that does not degrade the physical properties of the hard coating composition according to the present invention, and is therefore not particularly limited.

[0074] The leveling agent is a component that imparts smoothness and coating properties to the coating film. The leveling agent can be any leveling agent commonly used in the industry, such as silicone-based leveling agents, fluorine-based leveling agents, or acrylic polymer-based leveling agents. These can be used individually or in combination of two or more, but are not necessarily limited to these. In one embodiment of the present invention, the hard coating layer preferably further contains a silicone-based or acrylic polymer-based additive instead of a fluorine-based UV-curable functional group-containing compound contained in the low-refractive-index layer described later, in order to lower the contact angle and facilitate coating of a low-refractive-index layer on the hard coating layer.

[0075] 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.

[0076] UV stabilizers are components that block or absorb ultraviolet light, preventing decomposition, discoloration, and tearing of the hardened hard coating layer due to UV exposure. The UV stabilizers of the present invention include, in addition to absorbers, quenchers (Quenchers), hindered amine light stabilizers (HALS), etc., classified by their mechanism of action; or phenyl salicylates (absorbers), benzophenone (absorbers), benzotriazole (absorbers), nickel derivatives (quenchers), radical scavengers, etc., classified by their chemical structure. These can be used individually or in combination of two or more, and the type of UV stabilizer is not particularly limited as long as it does not significantly alter the initial hue of the hard coating layer.

[0077] As heat stabilizers, for example, commercially applicable products can use polyphenol-based primary heat stabilizers, phosphate-based and lactone-based secondary heat stabilizers, each individually or in combination. These can be used individually or in combination of two or more.

[0078] The UV stabilizer and heat stabilizer can be used in appropriate amounts that do not affect UV curability, and more specifically, they are preferably included in an amount of 0.1 to 3 parts by weight per 100 parts by weight of the total hard coating composition of the present invention.

[0079] The aforementioned additives can be added by appropriately adjusting their content within a range that does not impair the effects of the present invention.

[0080] The hard coating layer may be manufactured by methods known in the art. The thickness of the hard coating layer is not particularly limited, but may be, for example, 1 to 15 μm, preferably 2 to 10 μm. When the thickness is within the above range, it may be easier to control the transmittance of the laminated film including the hard coating layer at 360 nm and / or 380 nm wavelengths to 5% or less, and shrinkage during curing can be reduced, resulting in a film that does not curl excessively and simplifies the manufacturing process. On the other hand, if the thickness of the hard coating layer exceeds the above range, excessive curling due to curing occurs, which has the disadvantage of causing breakage during the manufacturing process.

[0081] The laminated film according to the embodiment of the present invention may be formed by applying a hard coating composition to a substrate and then drying and UV curing steps to form a hard coating layer 100.

[0082] The step of drying the laminated film may be carried out by heating means such as a hot plate, a hot air circulation furnace, or an infrared furnace, and may be carried out at a temperature of 50 to 150°C or 50 to 100°C.

[0083] The step of curing the laminated film involves a concentration of 50 to 1000 mJ / cm². 2 Preferably, 200 to 800 mJ / cm² 2 The device is irradiated with active rays such as UV light. Light sources that can be used for irradiation include low-pressure mercury lamps, high-pressure mercury lamps, ultra-high-pressure mercury lamps, metal halide lamps, and argon gas lasers. Depending on the situation, X-rays and electron beams may also be used.

[0084] Base material 200 In one embodiment of the present invention, the substrate 200 is preferably an ultraviolet-blocking substrate, and more specifically, it is preferable from the viewpoint of display protection that its transmittance at a wavelength of 380 nm is 10% or less. When the transmittance of the substrate at a wavelength of 380 nm is 10% or less, there is an advantage that wavelengths in the ultraviolet region can be effectively blocked and the degree of curing of the coating layer can be ensured. The ultraviolet-blocking substrate of the present invention includes having an ultraviolet-blocking function by containing an ultraviolet-blocking additive.

[0085] In addition to its ultraviolet blocking function, the substrate may also serve to mitigate impact and / or scratch damage to the front surface of the substrate layer, thereby preventing damage to the internal substrate. For this reason, materials with a high tolerance for deformation energy are preferred, such as polyester resins such as polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, and polybutylene naphthalate; polyimide resins; acrylic resins; styrene resins such as polystyrene and acrylonitrile-styrene; polycarbonate resins; polylactic acid resins; polyurethane resins; polyolefin resins such as polyethylene, polypropylene, and ethylene-propylene copolymers; vinyl resins such as polyvinyl chloride and polyvinylidene chloride; polyamide resins; sulfone resins; polyether-etherketone resins; arylate resins; cellulose resins such as triacetylcellulose, or release films formed from mixtures of the above resins. In one embodiment of the present invention, cellulose resins are most preferred in terms of being optically transparent and having excellent durability against friction, heat, and / or chemical damage.

[0086] While there are no restrictions on the thickness of the substrate using the aforementioned cellulose resin, thicker substrates are heavier and harder to handle, so a thickness of 25 to 80 μm is preferable for a display protective film.

[0087] A substrate 200 according to one embodiment of the present invention may contain an ultraviolet blocking additive. When the substrate contains an ultraviolet blocking additive, it can effectively block ultraviolet light in the region of 400 nm or less, prevent degradation of OLED elements, and improve the problem of shortened display lifespan. The ultraviolet blocking additive may be a benzophenone compound, a benzotriazole, or a triazine compound, but is not limited thereto, and is preferably included in an amount of 0.1% to 10% of the total weight of the composition forming the substrate.

[0088] The thickness of the substrate is not particularly limited and may be, for example, 10 to 100 μm. When the thickness is within the above range, it is suitable and preferable for display protective films.

[0089] <Image display device> Figure 1 shows the laminated structure of a laminated film according to one embodiment of the present invention. Referring to Figure 1, the embodiment of the present invention provides a laminated film comprising a hard coating layer 100 and a substrate 200, and an image display device comprising the same.

[0090] For example, a laminated film may be formed by sequentially stacking the hard coating layer 100 and the substrate 200 described above. In this case, the laminated film including the hard coating layer 100 and the substrate 200 may be formed on the outermost surface of the image display device, or it may be inserted inside the image display device, as required by the image display device.

[0091] The aforementioned image display device includes, but is not limited to, various image display devices such as liquid crystal display devices, electroluminescent display devices, plasma display devices, and field emission display devices, and may be a flexible display device having flexibility and bending characteristics. In this case, the laminated film according to the embodiment of the present invention, i.e., the hard-coated laminate, reduces transmittance in the ultraviolet and / or near-ultraviolet region through the above configuration and improves mechanical properties such as adhesion, thereby preventing haze and preventing degradation of the OLED element, and realizing an image display device with excellent total transmittance and adhesion. [Examples]

[0092] The present invention will be described in further detail below based on examples, but the embodiments of the present invention disclosed below are merely illustrative, and the scope of the present invention is not limited to these embodiments. The scope of the present invention is set forth in the claims, and all modifications are equivalent in meaning and scope to those stated in the claims. In addition, the percentages and parts indicated in the following examples and comparative examples are by weight unless otherwise specified.

[0093] Manufacturing Examples 1 to 5: Manufacturing of Hard Coating Compositions Manufacturing Example 1 A hard coating composition was prepared by mixing 50.8 parts by weight of hexafunctional urethane acrylate (UA-306I, manufactured by Kyoeisha), 44.6 parts by weight of butyl acetate, 3.3 parts by weight of 1-hydroxycyclohexyl phenyl ketone, 0.3 parts by weight of a silicone-based leveling agent (BYK-UV3530, manufactured by BYK), 0.5 parts by weight of a near-ultraviolet absorber (FDB-009 (λmax=402nm), manufactured by Yamada Co., Ltd.), and 0.5 parts by weight of an ultraviolet light enhancer / decreaser (NF-TH-01 (λmax=375nm), manufactured by Nippon Chemical Works Co., Ltd.) using a stirrer and filtering the mixture through a PP filter.

[0094] Manufacturing Example 2 A hard coating composition was prepared by mixing 50.6 parts by weight of hexafunctional urethane acrylate (UA-306I, manufactured by Kyoeisha), 44.2 parts by weight of butyl acetate, 3.3 parts by weight of 1-hydroxycyclohexyl phenyl ketone, 0.3 parts by weight of a silicone-based leveling agent (BYK-UV3530, manufactured by BYK), 0.5 parts by weight of a near-ultraviolet absorber (FDB-009 (λmax=402nm), manufactured by Yamada Co., Ltd.), and 1.1 parts by weight of an ultraviolet light enhancer / depletor (NF-NA-01 (λmax=379nm), manufactured by Nippon Chemical Works) using a stirrer and filtering the mixture using a PP filter.

[0095] Manufacturing Example 3 A hard coating composition was prepared by mixing 50.0 parts by weight of hexafunctional urethane acrylate (UA-306I, manufactured by Kyoeisha), 43.8 parts by weight of butyl acetate, 3.2 parts by weight of 1-hydroxycyclohexyl phenyl ketone, 0.3 parts by weight of a silicone-based leveling agent (BYK-UV3530, manufactured by BYK), and 2.7 parts by weight of an ultraviolet absorber (TINUVIN 970 (λmax=378nm), manufactured by BASF) using a stirrer and filtering the mixture through a PP filter.

[0096] Manufacturing Example 4 A hard coating composition was prepared by mixing 51.1 parts by weight of hexafunctional urethane acrylate (UA-306I, manufactured by Kyoeisha), 44.8 parts by weight of butyl acetate, 3.3 parts by weight of 1-hydroxycyclohexyl phenyl ketone, 0.3 parts by weight of a silicone-based leveling agent (BYK-UV3530, manufactured by BYK), and 0.5 parts by weight of a near-ultraviolet absorber (FDB-009 (λmax=402nm), manufactured by Yamada Co., Ltd.) using a stirrer and filtering the mixture through a PP filter.

[0097] Manufacturing Example 5 A hard coating composition was prepared by mixing 49.8 parts by weight of hexafunctional urethane acrylate (UA-306I, manufactured by Kyoeisha), 43.5 parts by weight of butyl acetate, 3.2 parts by weight of 1-hydroxycyclohexyl phenyl ketone, 0.3 parts by weight of a silicone-based leveling agent (BYK-UV3530, manufactured by BYK), 2.7 parts by weight of an ultraviolet absorber (TINUVIN 970 (λmax=378nm), manufactured by BASF), and 0.5 parts by weight of a near-ultraviolet absorber (FDB-009 (λmax=402nm)) using a stirrer and filtering the mixture using a PP filter.

[0098] Examples 1 to 2 and Comparative Examples 1 to 4: Manufacturing of Laminated Films Example 1 The hard coating composition produced according to Production Example 1 was cured onto a UV-blocking substrate (80 μm TAC film, manufactured by HYOSUNG) and coated to a thickness of 6 μm, then solvent-dried and exposed to UV light at an integrated intensity of 500 mJ / cm² under a nitrogen atmosphere. 2 A laminated film is manufactured by irradiating it with light.

[0099] Example 2 The hard coating composition produced according to Production Example 2 was cured onto a UV-blocking substrate (80 μm TAC film, manufactured by HYOSUNG) and coated to a thickness of 6 μm, then solvent-dried and exposed to UV light at an integrated intensity of 500 mJ / cm² under a nitrogen atmosphere. 2 A laminated film is manufactured by irradiating it with light.

[0100] Comparative Example 1 The hard coating composition produced according to Production Example 3 was cured onto a UV-blocking substrate (80 μm TAC film, manufactured by HYOSUNG) and coated to a thickness of 6 μm, then solvent-dried and exposed to UV light at an integrated intensity of 500 mJ / cm² under a nitrogen atmosphere. 2 A laminated film is manufactured by irradiating it with light.

[0101] Comparative Example 2 The hard coating composition produced according to Production Example 4 was cured onto a UV-blocking substrate (80 μm TAC film, manufactured by HYOSUNG) and coated to a thickness of 6 μm, then solvent-dried and exposed to UV light at an integrated intensity of 500 mJ / cm² under a nitrogen atmosphere. 2 A laminated film is manufactured by irradiating it with light.

[0102] Comparative Example 3 The hard coating composition produced according to Production Example 5 was cured onto a UV-blocking substrate (80 μm TAC film, manufactured by HYOSUNG) and coated to a thickness of 6 μm, then solvent-dried and exposed to UV integrated light of 500 mJ / cm² under a nitrogen atmosphere. 2 A laminated film is manufactured by irradiating it with light.

[0103] Comparative Example 4 The hard coating composition produced according to Production Example 1 was cured onto a transparent substrate (80 μm ZRT film, manufactured by HYOSUNG) and coated to a thickness of 6 μm, then solvent-dried and exposed to UV light at an integrated intensity of 500 mJ / cm² under a nitrogen atmosphere. 2 A laminated film is manufactured by irradiating it with light.

[0104] The manufacturing examples, substrates used, and the thickness of each layer applied to Examples 1 to 2 and Comparative Examples 1 to 4, respectively, are as described in Table 1 below.

[0105] [Table 1]

[0106] Experimental example The physical properties of the laminated films produced in Examples 1 to 2 and Comparative Examples 1 to 4 were measured by the following method, and the results are shown in Table 2.

[0107] (1) Measurement of ultraviolet (360nm) transmittance The transmittance of the laminated films of the above examples and comparative examples at a wavelength of 360 nm was measured using a UV-2600 (manufactured by Shimadzu Corporation) and is shown in Table 2.

[0108] (2) Measurement of ultraviolet (380nm) transmittance The transmittance of the laminated films of the above examples and comparative examples at a wavelength of 380 nm was measured using a UV-2600 (manufactured by Shimadzu Corporation) and is shown in Table 2.

[0109] (3) Measurement of near-ultraviolet (400nm) transmittance The transmittance of the laminated films of the above examples and comparative examples at a wavelength of 400 nm was measured using a UV-2600 (manufactured by Shimadzu Corporation) and is shown in Table 2.

[0110] (4) Measurement of Total Transmittance (Tt) The total light transmittance of the laminated films of the above examples and comparative examples was measured using a haze meter (HR-100, manufactured by Murakami Co., Ltd.) according to JIS 7136 and is shown in Table 2.

[0111] (5) Measurement of haze The haze of the laminated films of the above examples and comparative examples was measured according to JIS 7136 using a haze meter (HR-100, manufactured by Murakami Co., Ltd.) and is shown in Table 2.

[0112] (6) Evaluation of adhesion After bonding the base film to the glass using a transparent adhesive so that the hard-coated side was facing upwards, the hard-coated surface was scratched with a cutter knife in a shape of 100 squares horizontally and vertically at 1 mm intervals, and then adhesion tests were performed three times using Nichiban tape. <Evaluation Criteria> -0B: More than 65% peeling -1B: Peeling of 35% to less than 65% -2B: Peeling of 15% to less than 35% -3B: 5% to less than 15% peeling -4B: Less than 5% peeling -5B: Unpeeled

[0113] [Table 2]

[0114] According to the experimental data in Table 2 above, the physical properties of the laminated films produced in Examples 1 and 2 of the present invention were evaluated, and the films of the above examples satisfied transmittances of 5%, 5%, and 10% or less at 360 nm, 380 nm, and 400 nm, respectively, and were not peeled off in the adhesion evaluation, showing excellent ultraviolet and near-ultraviolet shielding effects and excellent adhesion effects.

[0115] In contrast, in Comparative Example 1, which used a hard coating composition that did not contain near-ultraviolet absorbers and ultraviolet light enhancers / decreasers, it was found that the transmittance in the 400 nm wavelength range was higher and the near-ultraviolet shielding effect was significantly reduced compared to the example according to the present invention.

[0116] Furthermore, in Comparative Example 3, which used a hard coating composition that did not contain an ultraviolet light enhancer or reducer, the adhesion was significantly lower than in the example according to the present invention, and it was found to be unsuitable as a film for protecting OLED elements.

[0117] Furthermore, in Comparative Example 4, which does not use an ultraviolet-blocking substrate, the transmittance in the 360nm and 380nm wavelength regions was higher than in the example according to the present invention, indicating a significant decrease in the ultraviolet shielding effect.

[0118] In summary, these results show that if either the hard coating layer containing the near-ultraviolet absorber and ultraviolet light enhancer / decreaser, or the substrate containing the ultraviolet blocking additive, which are components of the present invention, is excluded from the invention's configuration, then one or more of the results in the evaluation of ultraviolet transmittance, near-ultraviolet transmittance, and adhesion will be inferior to those of the embodiments of the present invention.

[0119] Therefore, a laminated film according to one embodiment of the present invention comprises a hard coating layer and a substrate, the hard coating layer comprises a near-ultraviolet absorber and an ultraviolet light enhancer / decreaser, and the substrate comprises an ultraviolet blocking additive, and can exhibit excellent ultraviolet and / or near-ultraviolet shielding effects and maintain excellent mechanical properties such as adhesion. [Industrial applicability]

[0120] The laminated film according to the present invention has low transmittance in the ultraviolet and / or near-ultraviolet region, which effectively blocks ultraviolet and / or near-ultraviolet light, thereby preventing degradation of OLED elements and improving the problem of shortened display lifespan. [Explanation of Symbols]

[0121] 100: Hard coating layer 200: Base material

Claims

1. A laminated film comprising a hard coating layer and a substrate, The hard coating layer comprises a near-ultraviolet absorber and an ultraviolet light enhancer / decreaser. The aforementioned substrate is an ultraviolet-blocking substrate. Laminated film.

2. The substrate is characterized by having a transmittance of 10% or less at a wavelength of 380 nm. The laminated film according to claim 1.

3. The aforementioned substrate is characterized by containing an ultraviolet blocking additive. The laminated film according to claim 1.

4. The substrate is characterized by being one or more selected from polyester films, cellulose films, and polyimide films. The laminated film according to claim 1.

5. The near-ultraviolet absorber is characterized in that its maximum absorption wavelength is 390 nm to 430 nm. The laminated film according to claim 1.

6. The aforementioned near-ultraviolet absorber is characterized by being a cyanine-based compound. The laminated film according to claim 1.

7. The UV light enhancer / depressor is characterized by having a maximum absorption wavelength of 350 nm to 400 nm. The laminated film according to claim 1.

8. The ultraviolet light enhancer / decreaser is characterized by being an oxazole compound. The laminated film according to claim 1.

9. The hard coating layer was manufactured from a hard coating composition. The hard coating composition is characterized by comprising a near-ultraviolet absorber, an ultraviolet light enhancer / decreaser, a photocurable resin, and a solvent. The laminated film according to claim 1.

10. The near-ultraviolet absorber is characterized by being included in an amount of 0.1 to 1 part by weight relative to the total weight of the hard coating composition. The laminated film according to claim 9.

11. The ultraviolet light intensity modifier is characterized by being included in an amount of 0.1 to 2 parts by weight relative to the total weight of the hard coating composition. The laminated film according to claim 9.

12. The laminated film is characterized by having a total light transmittance of 85% or more. The laminated film according to claim 1.

13. The haze of the laminated film is characterized by being 2% or less. The laminated film according to claim 1.

14. The laminated film is characterized by having a transmittance of 5% or less at a wavelength of 360 nm. The laminated film according to claim 1.

15. The laminated film is characterized by having a transmittance of 5% or less at a wavelength of 380 nm. The laminated film according to claim 1.

16. The laminated film is characterized by having a transmittance of 10% or less at a wavelength of 400 nm. The laminated film according to claim 1.

17. A laminated film comprising the one described in any one of claims 1 to 16, Image display device.

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