Hard coating film

Abstract

The present invention provides a hard coat film which suppresses the generation of circular defects caused by depressions at the time of coating of a hard coat layer, and the generation of bleed marks caused by bleeding of a leveling agent, and which is free from defects on the surface of the hard coat layer, and has a good appearance. The hard coat film of the present invention has a hard coat layer containing an ultraviolet-curable resin, a silicone-based leveling agent, and an ultraviolet absorber, layered on at least one side of a transparent substrate, and the ratio A / B of the peak intensity A at 1035 cm ‑1 -1 to the peak intensity B at 1450 cm ‑1 -1 of the surface of the hard coat layer, measured by an infrared spectrophotometer, is 1.46 or greater and less than 1.49.

Description

Technical Field

[0001] This invention relates to hard coatings for optical components. More specifically, it relates to hard coatings that can be used as protective films for components of display devices such as organic electroluminescent (EL) display devices, liquid crystal display devices (LCD) and plasma display devices, and touch panels. Background Technology

[0002] For example, the display surfaces of displays such as organic electroluminescent (EL) displays and liquid crystal displays (LCDs) require scratch resistance to prevent scratches during operation that could reduce visual clarity. Therefore, hard coatings, which consist of a hard coating layer on a substrate film, are commonly used to impart scratch resistance to the display surfaces.

[0003] In recent years, with the trend towards thinner and lighter displays, the thinner materials of their constituent components are also being developed. For example, the hard coating used in the polarizers of displays also requires thinner film.

[0004] In addition, when using the above-mentioned hard coating film as a protective film on the surface of an organic EL display, the hard coating film is required to meet several requirements, such as: not having an adverse effect on the display color and brightness of the organic EL display, being able to improve the durability (light resistance) of the light-emitting elements of the organic EL display, and being able to suppress the display degradation of the organic EL display.

[0005] As prior art, for example, Patent Document 1 discloses a film-forming composition comprising a triazine ring-containing polymer capable of forming a thin film with high refractive index and excellent lightfastness. Additionally, for example, Patent Document 2 discloses a film-forming composition comprising a hyperbranched polymer containing a triazine ring capable of forming a film with a thickness of 1000 nm or more and high transparency and lightfastness.

[0006] Existing technical documents

[0007] Patent documents

[0008] Patent Document 1: International Publication No. 2017 / 110810

[0009] Patent Document 2: International Publication No. 2013 / 094664 Summary of the Invention

[0010] The problem that the invention aims to solve

[0011] To suppress damage such as degradation of several polymers used in organic EL displays, fading of pigments, and discoloration, it is necessary to sufficiently reduce the transmittance at wavelengths in the near-ultraviolet region, such as 380 nm. Furthermore, to improve the durability (lightfastness) of the light-emitting elements in recent organic EL displays, it is necessary to sufficiently reduce the transmittance at 410 nm to protect the light-emitting elements. However, films obtained from the film-forming compositions disclosed in Patent Documents 1 and 2 exhibit very high transmittance at 380 nm and 410 nm, failing to address the issues of suppressing damage such as degradation of several polymers used in organic EL displays, fading of pigments, and discoloration, and improving the durability (lightfastness) of the light-emitting elements in organic EL displays.

[0012] To reduce light transmittance in the near-ultraviolet region, near-ultraviolet absorbers, such as sesamol-type benzotriazole-based UV absorbers, are effective. However, when these near-ultraviolet absorbers are added to hard coatings, the surface tension increases, making it easy to create depressions during coating and resulting in numerous circular defects on the surface of the hard coating.

[0013] Adding leveling agents is effective in adjusting the surface tension of hard coatings. Furthermore, considering cost and environmental impact, there has been a growing trend in recent years to shift from fluorinated to silicone-based leveling agents as leveling agents added to hard coatings. However, conventional silicone-based leveling agents generally have higher surface tension compared to fluorinated leveling agents, making them prone to sink marks. While increasing the amount of leveling agent can reduce surface tension, this also leads to seepage, creating a new problem of blisters on the surface of the hard coating.

[0014] Therefore, the objectives of this invention are: first, to provide a hard coating film that suppresses the generation of circular defects caused by depressions during hard coating application and the generation of puffs caused by the exudation of leveling agents, resulting in a defect-free hard coating surface and a good appearance; second, to provide a hard coating film that, when used as a protective film for the surface of an organic EL display, does not adversely affect the display color or brightness of the organic EL display, and can improve the durability (lightfastness) of the light-emitting elements of the organic EL display, thereby suppressing display degradation of the organic EL display; and third, to provide a hard coating film that maintains the above-mentioned properties even after a lightfastness test.

[0015] Methods for solving problems

[0016] In order to solve the above-mentioned problems, the inventors conducted in-depth research and found that the above-mentioned problems can be solved by an invention having the following structure.

[0017] That is, the present invention has the following structure.

[0018] (First Invention)

[0019] A hard coating film, characterized in that a hard coating layer containing an ultraviolet-curable resin, an organosilicon leveling agent, and an ultraviolet absorber is laminated on at least one side of a transparent substrate, wherein the surface of the hard coating layer measures 1035 cm⁻¹ using an infrared spectrophotometer. -1 Peak intensity A and 1450 cm -1 The ratio of peak intensity B to peak intensity B, A / B, is greater than 1.46 and less than 1.49.

[0020] (Second Invention)

[0021] According to the hard coating film of the first invention, the light reduction rate (%) of the hard coating film at each wavelength calculated by the following formula 1 satisfies the following conditions (A) to (C).

[0022] Equation 1) Light reduction rate (%) at each wavelength = (transmittance of the transparent substrate itself at that wavelength - transmittance of the hard coating at that wavelength) / transmittance of the transparent substrate itself at that wavelength

[0023] (A) The light reduction rate at a wavelength of 380nm is over 95.0%.

[0024] (B) The light reduction rate at a wavelength of 410nm is above 70.0% and below 90.0%.

[0025] (C) The light reduction rate at a wavelength of 435nm is less than 15.0%.

[0026] (Third Invention)

[0027] According to the hard coating film of the first or second invention, the hard coating film is characterized by b The value is below 5.0.

[0028] (Fourth Invention)

[0029] According to the hard coating film of the first or second invention, the characteristic is that, in an image obtained by taking a 3mm × 3mm or larger area image of the surface of the hard coating film using an optical microscope with a magnification of 50x, the number of circular defects with a diameter of 30μm or larger per 1mm is [missing information]. 2 Less than 5.

[0030] (Fifth Invention)

[0031] According to the first or second invention, the hard coating film is characterized in that, in an image obtained by taking a picture of the surface of the hard coating film with an area of ​​3mm × 3mm or more using an optical microscope with a magnification of 50x, the area occupied by circular defects with a diameter of 30μm or more is less than 10%.

[0032] (Sixth Invention)

[0033] According to the hard coating film of the first or second invention, the organosilicon leveling agent is a polyether-modified polydimethylsiloxane or a polyester-modified polydimethylsiloxane.

[0034] (Seventh Invention)

[0035] According to the hard coating film of the first or second invention, the amount of the silicone-based leveling agent is 0.3 to 1.4 parts by mass relative to 100 parts by mass of the UV-curable resin of the hard coating film.

[0036] (Eighth Invention)

[0037] The hard coating film according to the first or second invention is characterized in that the ultraviolet absorber is a sesamol-type benzotriazole ultraviolet absorber.

[0038] (Ninth Invention)

[0039] According to the hard coating film of the eighth invention, the weight-average molecular weight of the sesamol-type benzotriazole ultraviolet absorber is in the range of 15,000 to 35,000.

[0040] (Tenth Invention)

[0041] According to the first or second invention, the hard coating film is characterized in that the value defined by the concentration C (mass %) of the ultraviolet absorber contained in the hard coating film and the film thickness D (μm) of the hard coating film is in the range of 0.65 (mass %·μm) or more and 1.38 (mass %·μm) or less.

[0042] (Eleventh Invention)

[0043] According to the hard coating film of the first or second invention, the hard coating film is characterized by having an irradiance of 500 W / m² under an environment of 63°C and 50% relative humidity. 2 After 100 hours of ultraviolet irradiation (light resistance test), the light reduction rate (%) at each wavelength calculated by the following formula 1 satisfies the following conditions (D) to (F).

[0044] Equation 1) Light reduction rate (%) at each wavelength = (transmittance of the transparent substrate itself at that wavelength - transmittance of the hard coating at that wavelength) / transmittance of the transparent substrate itself at that wavelength

[0045] (D) The light reduction rate at a wavelength of 380nm is over 95.0%.

[0046] The light reduction rate at a wavelength of (E)410nm is above 70.0% and below 90.0%.

[0047] The light reduction rate at (F)435nm wavelength is less than 15.0%.

[0048] (Twelfth Invention)

[0049] The hard coating film according to the first or second invention is characterized in that the transparent substrate is a triacetyl cellulose film, a polyethylene terephthalate film, or a cyclic olefin polymer film.

[0050] Invention Effects

[0051] According to the present invention, a hard coating film can be provided, wherein the generation of circular defects caused by depressions during hard coating application and the generation of puffing caused by the exudation of leveling agent are suppressed, and the hard coating surface is free of defects and has a good appearance.

[0052] Furthermore, according to the present invention, a hard coating film can be provided that, when used as a protective film on the surface of an organic EL display, does not adversely affect the display color or brightness of the organic EL display, and can improve the durability (light resistance) of the light-emitting elements of the organic EL display and suppress display degradation of the organic EL display.

[0053] Furthermore, according to the present invention, a hard coating film that can maintain the above-mentioned properties even after a lightfastness test for a hard coating film can be provided. Detailed Implementation

[0054] The following describes in detail the methods for implementing the present invention, but the present invention is not limited to the following embodiments.

[0055] It should be noted that, unless otherwise specified, in this instruction manual, the range “xx~yy” refers to “above xx and below yy”.

[0056] As described in the first invention above, the hard coating film of the present invention is characterized in that a hard coating layer containing an ultraviolet-curable resin, an organosilicon leveling agent, and an ultraviolet absorber is laminated on at least one side of a transparent substrate, and the surface of the hard coating layer has a 1035 cm⁻¹ depth measured using an infrared spectrophotometer. -1 Peak intensity A and 1450 cm -1 The ratio of peak intensity B to peak intensity B, A / B, is greater than 1.46 and less than 1.49.

[0057] The structure of the hard coating film of the present invention will be described in detail below.

[0058] [Transparent substrate]

[0059] First, the transparent substrate of the above-mentioned hard coating will be described.

[0060] Transparent film substrates are typically used as the substrates for coating the hard coating film of the present invention.

[0061] The transparent film substrate used in this invention is not particularly limited as long as it is transparent. Examples include resin films comprising acrylic resins, triacetyl cellulose, polyethylene terephthalate, cyclic olefin polymers, polycarbonate, polyethylene naphthalate, polyethylene, polyethylene, polypropylene terephthalate, polypropylene, polybutylene terephthalate, polystyrene, polymethyl methacrylate, glycidyl methacrylate, aromatic polyimide, alicyclic polyimide, polyamide-imide, and mixtures thereof.

[0062] Here, "transparency" refers to a total light transmittance of 80% or more as measured according to JIS-K7136.

[0063] In this invention, from the viewpoint of transparency, optical properties, and versatility of optical films for displays, triacetyl cellulose films, polyethylene terephthalate films, or cyclic olefin polymer films are particularly preferred among these film substrates.

[0064] In this invention, the thickness of the aforementioned transparent substrate can be appropriately selected according to the application, but from the viewpoint of meeting the requirements for thin-film displays and lightweight hard coating films, it is preferably 50 μm or less, and particularly preferably 30 μm or less. On the other hand, from the viewpoint of mechanical strength, processability, etc., it is preferably 10 μm or more.

[0065] [Hard coating]

[0066] Next, the hard coating layer of the above-mentioned hard coating film will be described.

[0067] In this invention, the above-mentioned hard coating contains at least a UV-curable resin, a silicone-based leveling agent, and a UV absorber.

[0068] In this invention, the resin contained in the above-mentioned hard coating is preferably a UV-curable resin, which is preferred from the perspective of imparting surface hardness (pencil hardness, scratch resistance) to the hard coating and the ability to adjust the degree of crosslinking and the surface hardness of the hard coating by adjusting the amount of UV exposure.

[0069] The UV-curable resin used in this invention is not particularly limited to any transparent resin that is cured by irradiation with ultraviolet (UV) light. However, for the sake of coating hardness and the formation of a three-dimensional cross-linked structure in the hard coating, it is preferable to include a UV-curable polyfunctional acrylate having three or more (meth)acryloyloxy groups within one molecule. Specific examples of UV-curable polyfunctional acrylates having three or more (meth)acryloyloxy groups within one molecule include trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol tri(meth)acrylate, dipentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, trimethylolpropane ethoxytriacrylate, glyceryl propoxytriacrylate, and bis(trimethylolpropane tetraacrylate). It should be noted that polyfunctional acrylates can be used not only alone but also in combination of two or more types.

[0070] Furthermore, the UV-curable resin used in the aforementioned hard coating is preferably a monomer, oligomer, or polymer with a weight-average molecular weight in the range of 500 to 3600, more preferably in the range of 500 to 3000, and even more preferably in the range of 500 to 2400. When the weight-average molecular weight is less than 500, the curing shrinkage during UV curing is large, and the phenomenon of warping (curling) of the hard coating film towards the hard coating surface becomes greater, resulting in defects during subsequent processing steps and poor processing adaptability. In addition, when the weight-average molecular weight exceeds 3600, the flexibility of the hard coating increases, but the hardness is insufficient, and therefore it is not suitable.

[0071] It should be noted that the weight-average molecular weight in this invention is the average molecular weight obtained by gel permeation chromatography (GPC) analysis and converted to standard polystyrene.

[0072] Furthermore, when the weight-average molecular weight of the UV-curable resin used in the above-mentioned hard coating is less than 1500, the number of functional groups per molecule is preferably 3 or more and less than 10. Conversely, when the weight-average molecular weight of the UV-curable resin is 1500 or more, the number of functional groups per molecule is preferably 3 or more and less than 20. Within these ranges, curling can be suppressed, and appropriate processing adaptability can be maintained.

[0073] In addition to the UV-curable resins mentioned above, the resins contained in the aforementioned hard coating can also be thermoplastic resins such as polyethylene, polypropylene, polystyrene, polycarbonate, polyester, acrylic, styrene-acrylic, and cellulose, as well as thermosetting resins such as phenolic resin, urea resin, unsaturated polyester, epoxy, and silicone resin, within a range that does not impair the hardness and scratch resistance of the hard coating.

[0074] In this invention, the above-mentioned hard coating contains an ultraviolet absorber in addition to the ultraviolet-curable resin.

[0075] In this invention, a sesamol-type benzotriazole-based ultraviolet absorber with high wavelength absorption in the near-ultraviolet region (hereinafter, sometimes referred to as "the ultraviolet absorber of this invention") is particularly preferred.

[0076] The ultraviolet absorber of the present invention is formed by polymerizing a sesamol-type benzotriazole monomer with, for example, an acrylate resin component.

[0077] Here, the sesamol-type benzotriazole monomer, for example represented by the following general formula (I), is a derivative of a compound in which sesamol is bonded to the nitrogen atom at the 2 position of the benzotriazole ring.

[0078]

[0079] In the above formula, R1 represents a hydrogen atom or a methyl group. Additionally, R2 represents a straight-chain or branched alkylene group having 1 to 6 carbon atoms, or a straight-chain or branched oxoalkylene group having 1 to 6 carbon atoms.

[0080] Specific examples of the sesamol-type benzotriazole monomers represented by the above general formula (I) include 2-[2-(6-hydroxybenzo[1,3]dioxacyclopenten-5-yl)-2H-benzotriazole-5-yl]ethyl methacrylate, 2-[2-(6-hydroxybenzo[1,3]dioxacyclopenten-5-yl)-2H-benzotriazole-5-yl]ethyl methacrylate, 3-[2-(6-hydroxybenzo[1,3]dioxacyclopenten-5-yl)-2H-benzotriazole-5-yl]propyl methacrylate, 3-[2-(6-hydroxybenzo[1,3]dioxacyclopenten-5-yl)-2H-benzotriazole- 5-yl]propyl acrylate, 4-[2-(6-hydroxybenzo[1,3]dioxacyclopenten-5-yl)-2H-benzotriazol-5-yl]butyl methacrylate, 4-[2-(6-hydroxybenzo[1,3]dioxacyclopenten-5-yl)-2H-benzotriazol-5-yl]butyl methacrylate, 2-[2-(6-hydroxybenzo[1,3]dioxacyclopenten-5-yl)-2H-benzotriazol-5-yloxy]ethyl methacrylate, 2-[2-(6-hydroxybenzo[1,3]dioxacyclopenten-5-yl)-2H-benzotriazol-5-yloxy]ethyl methacrylate, 2-[3-{ 2-(6-hydroxybenzo[1,3]dioxacyclopenten-5-yl)-2H-benzotriazol-5-yl}propionyloxy]ethyl methacrylate, 2-[3-{2-(6-hydroxybenzo[1,3]dioxacyclopenten-5-yl)-2H-benzotriazol-5-yl}propionyloxy]ethyl methacrylate, 4-[3-{2-(6-hydroxybenzo[1,3]dioxacyclopenten-5-yl)-2H-benzotriazol-5-yl}propionyloxy]butyl methacrylate, 4-[3-{2-(6-hydroxybenzo[1,3]dioxacyclopenten-5-yl)-2H-benzotriazol-5-yl}propionyloxy]butyl Acrylates, 2-(methacryloyloxy)ethyl-2-(6-hydroxybenzo[1,3]dioxacyclopenten-5-yl)-2H-benzotriazole-5-carboxylic acid ester, 2-(acryloyloxy)ethyl-2-(6-hydroxybenzo[1,3]dioxacyclopenten-5-yl)-2H-benzotriazole-5-carboxylic acid ester, 4-(methacryloyloxy)butyl-2-(6-hydroxybenzo[1,3]dioxacyclopenten-5-yl)-2H-benzotriazole-5-carboxylic acid ester, 4-(acryloyloxy)butyl-2-(6-hydroxybenzo[1,3]dioxacyclopenten-5-yl)-2H-benzotriazole-5-carboxylic acid ester, etc.

[0081] The ultraviolet absorber of the present invention can be obtained by polymerizing the above-mentioned sesamol-type benzotriazole monomer with other monomer components (such as methyl methacrylate, ethyl methacrylate, propyl methacrylate, isopropyl methacrylate, butyl methacrylate, isobutyl methacrylate, tert-butyl methacrylate, octyl methacrylate, nonyl methacrylate, and other acrylate resin components). The polymerization method can be conventionally known methods such as solution polymerization, emulsion polymerization, suspension polymerization, and bulk polymerization.

[0082] Furthermore, in this invention, it is particularly preferred to use a sesamol-type benzotriazole-based ultraviolet absorber with a weight-average molecular weight in the range of 15,000 to 35,000.

[0083] In contrast, when using sesamol-type benzotriazole UV absorbers with a weight-average molecular weight of less than 15,000, the transmittance at 410 nm cannot be sufficiently reduced, resulting in display degradation in organic EL displays. Furthermore, when using sesamol-type benzotriazole UV absorbers with a weight-average molecular weight exceeding 35,000, their performance cannot be maintained after photosensitivity testing at 410 nm, leading to display degradation in organic EL displays and the inability to improve the durability (photoresistance) of the light-emitting elements.

[0084] It should be noted that the weight-average molecular weight of the above-mentioned sesamol-type benzotriazole UV absorbers was obtained by gel permeation chromatography (GPC) analysis and converted to standard polystyrene.

[0085] The ultraviolet absorber of the present invention can be used alone or in combination with two or more.

[0086] In addition, without impairing the effects of the present invention, other benzotriazole-based ultraviolet absorbers, hydroxyphenyltriazine-based ultraviolet absorbers, etc., may also be used in combination.

[0087] The hard coating of the present invention contains the ultraviolet absorber of the present invention described above in the hard coating layer, which enables the spectral characteristics (light reduction rate at each wavelength of 380nm, 410nm and 435nm) to meet the conditions (A) to (C).

[0088] As described above, in this invention, the thickness of the hard coating containing the UV absorber of this invention is preferably greater than 2.0 μm and less than 6.0 μm, particularly preferably in the range of 3.0 μm to 5.0 μm. When the thickness of the hard coating is greater than 2.0 μm and less than 6.0 μm, the amount of the UV absorber of this invention is preferably in the range of 20 to 60 parts by weight relative to 100 parts by weight of the UV-curable resin of the hard coating. When the amount of the UV absorber of this invention is less than 20 parts by weight, the thickness of the hard coating of this invention in the range of greater than 2.0 μm and less than 6.0 μm cannot sufficiently satisfy the spectral characteristics of this invention. On the other hand, when the amount of the UV absorber of this invention exceeds 60 parts by weight, the proportion of the UV-curable resin in the hard coating decreases, and therefore sometimes the adhesion of the hard coating to the film substrate decreases, or the hardness of the hard coating decreases, which is unsuitable.

[0089] Furthermore, when the thickness of the hard coating is set to be in the range of 3.0 μm to 5.0 μm, the amount of the ultraviolet absorber of the present invention is preferably in the range of 30 to 50 parts by mass relative to 100 parts by mass of the ultraviolet-curable resin of the hard coating.

[0090] In this invention, it is particularly preferred that the relationship between the concentration C (mass %) of the ultraviolet absorber contained in the hard coating and the film thickness D (μm) of the hard coating be adjusted to a range of 0.65 (mass %·μm) ≤ C × D ≤ 1.38 (mass %·μm). That is, it is preferable that the relationship between the concentration C (mass %) of the ultraviolet absorber contained in the hard coating and the film thickness D (μm) of the hard coating be adjusted to a range of 0.65 (mass %·μm) or more and 1.38 (mass %·μm) or less.

[0091] It should be noted that when the C×D value is less than 0.65 (mass%·μm), the transmittance at 410nm cannot be sufficiently reduced, thus leading to display degradation in organic EL displays. Furthermore, when the C×D value exceeds 1.38 (mass%·μm), the adhesion of the hard coating to the film substrate decreases, making it unsuitable. Additionally, excessive use of ultraviolet absorbers can cause exudation, making it unsuitable as well.

[0092] The hard coating of the present invention further contains an organosilicon-based leveling agent in the above-mentioned hard coating layer.

[0093] As the silicone-based leveling agent used in this invention, it is preferable to use a low molecular weight siloxane that is not a resin (polymer). Specifically, it is preferable to use, for example, polyether-modified polydimethylsiloxane or polyester-modified polydimethylsiloxane.

[0094] The amount of the silicone-based leveling agent is preferably 0.3 to 1.4 parts by weight relative to 100 parts by weight of the UV-curable resin of the hard coating.

[0095] Furthermore, as detailed later, it is important in this invention that the aforementioned hard coating contains an organosilicon-based leveling agent, and the surface area of ​​the hard coating, measured using an infrared spectrophotometer, is 1035 cm⁻¹. -1 Peak intensity A and 1450 cm -1 The ratio of peak intensity B to peak intensity B, A / B, is greater than 1.46 and less than 1.49.

[0096] Alternatively, inorganic oxide microparticles can be included in the aforementioned hard coating to further improve surface hardness (scratch resistance). In this case, the average particle size of the inorganic oxide microparticles is preferably in the range of 5 to 50 nm, and more preferably in the range of 10 to 40 nm. When the average particle size is less than 5 nm, it is difficult to obtain sufficient surface hardness. On the other hand, when the average particle size exceeds 50 nm, the gloss and transparency of the hard coating tend to decrease, and the flexibility may also decrease.

[0097] In this invention, examples of inorganic oxide particles include alumina and silicon dioxide. Alumina, being primarily composed of aluminum, has high hardness, thus achieving the desired effect with a lower addition amount than silicon dioxide, and is therefore particularly preferred.

[0098] In this invention, the content of inorganic oxide particles is preferably 0.1 to 10.0 parts by weight relative to 100 parts by weight of the UV-curable resin of the hard coating. When the content of inorganic oxide particles is less than 0.1 parts by weight, it is difficult to obtain an improvement in surface hardness (scratch resistance). On the other hand, when the content exceeds 10.0 parts by weight, the haze increases, which is therefore not preferred.

[0099] The coating used to form the above-mentioned hard coating may contain a photopolymerization initiator. As such a photopolymerization initiator, commercially available acetophenones such as IRGACURE 651 and IRGACURE 184 (both trade names: manufactured by BASF) and benzophenones such as IRGACURE 500 (trade name: manufactured by BASF) can be used.

[0100] As other additives added to the above-mentioned hard coating, pigments (e.g., anthocyanins), defoamers, surface tension modifiers, antifouling agents, antioxidants, antistatic agents, light stabilizers, etc., can be added as needed without impairing the effects of the present invention.

[0101] The aforementioned hard coating is formed as follows: the aforementioned UV-curable resin, UV absorber, silicone leveling agent, photopolymerization initiator, and other additives are dissolved and dispersed in a suitable solvent to form a hard coating. This coating is then applied to the aforementioned transparent substrate and dried, followed by UV curing. The solvent can be appropriately selected based on the solubility of the resin used. It can be a solvent capable of uniformly dissolving or dispersing the solid components (resin, UV absorber, silicone leveling agent, photopolymerization initiator, and other additives). For example, known organic solvents such as toluene, xylene, and n-heptane; aliphatic solvents such as cyclohexane, methylcyclohexane, and ethylcyclohexane; ester solvents such as methyl acetate, ethyl acetate, propyl acetate, isopropyl acetate, butyl acetate, and methyl lactate; ketone solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; and alcohol solvents such as methanol, ethanol, isopropanol, and n-propanol can be used alone or in appropriate combinations.

[0102] There are no particular limitations on the coating method for forming the above-mentioned hard coating. After coating by known methods such as gravure coating, micro-gravure coating, spray bar coating, sliding die coating, slot die coating, screen printing, and spraying, it is usually dried at a temperature of about 50 to 120°C.

[0103] The amount of ultraviolet (UV) irradiation after the above-mentioned hard coating film is formed can be the amount of irradiation required to make the hard coating have sufficient hardness, and can be appropriately set according to the type of UV-curable resin, etc.

[0104] In this invention, the thickness (film thickness) of the above-mentioned hard coating is preferably greater than 2.0 μm and less than 6.0 μm, and more preferably in the range of 3.0 μm to 5.0 μm.

[0105] When the thickness of the hard coating is less than 2.0 μm, the required hardness (e.g., scratch resistance) decreases, so it is not preferred. In addition, when the thickness of the hard coating is 6.0 μm or more, it is prone to strong curling, which reduces operability in manufacturing processes, etc., so it is not preferred. Furthermore, it is not preferred from the viewpoint of thinning the hard coating film.

[0106] It should be noted that, as described above, in this invention, the film thickness of the hard coating can be adjusted according to the relationship between the concentration C (mass %) of the ultraviolet absorber contained in the hard coating and the film thickness D (μm) of the hard coating, which is in the range of 0.65 (mass %·μm) ≤ C × D ≤ 1.38 (mass %·μm). That is, the film thickness of the hard coating can be adjusted according to the relationship with the concentration of the ultraviolet absorber. The value defined by the concentration C (mass %) of the ultraviolet absorber contained in the hard coating × the film thickness D (μm) of the hard coating is 0.65 (mass %·μm) or more and 1.38 (mass %·μm) or less.

[0107] It should be noted that the hard coating film of the present invention is laminated on at least one side of the transparent substrate. However, for example, when using a cyclic olefin polymer film as the transparent substrate, in order to improve the adhesion of the hard coating, it is also preferable to provide an easy-adhesive layer between the transparent substrate and the hard coating.

[0108] As for the resin used in the aforementioned easy-to-adhere layer, any resin that forms a film can be used without particular restrictions. For example, from the viewpoint of adhesion to the aforementioned transparent substrate film (cyclic olefin film), polyolefin resins, styrene acrylic resins, acrylic resins such as methyl methacrylate resins, epoxy resins, isocyanate resins, cellulose resins, or mixtures of two or more of these resins are preferred.

[0109] There is no particular limitation on the coating thickness of the above-mentioned easy-to-adhere layer. Preferably, it is within the range of 0.1μm to 5.0μm that does not adversely affect the adhesion to the substrate film and the hard coating or the pencil hardness of the hard coating.

[0110] As described above, the hard coating of the present invention is formed by laminating a hard coating containing a UV-curable resin, a silicone leveling agent and a UV absorber on at least one side of a transparent substrate.

[0111] Furthermore, the hard coating film of the present invention is characterized in that the surface of the aforementioned hard coating film has a density of 1035 cm⁻¹ as measured by an infrared spectrophotometer. -1 Peak intensity A and 1450 cm -1 The ratio of peak intensity B to peak intensity B, A / B, is greater than 1.46 and less than 1.49.

[0112] By ensuring that the ratio A / B satisfies the scope of the present invention, it is possible to suppress both the generation of circular defects caused by depressions during hard coating application and the generation of puffs caused by the exudation of leveling agents.

[0113] Here, the 1035 cm⁻¹ was measured using an infrared spectrophotometer. -1The peak intensity A originates from the stretching vibration of Si-O, and residues in siloxane-based leveling agents such as polyether-modified polydimethylsiloxane and polyester-modified polydimethylsiloxane that help suppress depressions. Additionally, 1450 cm⁻¹ -1 The peak intensity B originates from the variable-angle vibration of CH and the main framework of the UV-cured resin, which does not contribute to suppressing depressions. 1035cm -1 Peak intensity A and 1450 cm -1 The ratio of peak intensity B to A / B is the ratio of residues in the coating material that help suppress depressions, which in particular suggests that molecular motion based on Si-O stretching motion is the main reason for the exudation and depression suppression effect.

[0114] Furthermore, as an evaluation criterion related to the generation of circular defects, for example, in an image obtained by taking a 3mm × 3mm or larger area image of the aforementioned hard coating surface using an optical microscope with a magnification of 50x, if the number of circular defects with a diameter of 30μm or larger per 1mm... 2 If there are fewer than 5, the result is acceptable. Additionally, in an image of the hard-coated surface taken with a 50x optical microscope covering an area of ​​3mm x 3mm or larger, if the area occupied by circular defects with a diameter of 30μm or larger is less than 10%, the result is acceptable.

[0115] It should be noted that when the ratio A / B is less than 1.46, circular defects are easily generated. In addition, when the ratio A / B is 1.49 or higher, puffing spots caused by the exudation of leveling agent are easily generated. In either case, when the ratio A / B is outside the scope of the present invention, it is not possible to simultaneously suppress the generation of circular defects caused by depressions during hard coating and the generation of puffing spots caused by the exudation of leveling agent.

[0116] In addition, the hard coating of the present invention is characterized by satisfying the following optical properties.

[0117] That is, the hard coating of the present invention is characterized in that the light reduction rate (%) at each wavelength calculated by the following formula 1 satisfies the following conditions (A) to (C).

[0118] Equation 1) Light reduction rate (%) at each wavelength = (transmittance of the transparent substrate itself at that wavelength - transmittance of the hard coating at that wavelength) / transmittance of the transparent substrate itself at that wavelength

[0119] (A) The light reduction rate at a wavelength of 380nm is over 95.0%.

[0120] (B) The light reduction rate at a wavelength of 410nm is above 70.0% and below 90.0%.

[0121] (C) The light reduction rate at a wavelength of 435nm is less than 15.0%.

[0122] It should be noted that the specific methods for measuring the transmittance at each of the above wavelengths will be described in the embodiments described later.

[0123] Furthermore, the hard coating film of the present invention is characterized in that, b Values ​​below 5.0. b is particularly preferred. The value is below 4.3.

[0124] Therefore, the hard coating film of the present invention can incorporate b, which is an indicator of yellow tint. With a value suppressed below 5.0, it will not adversely affect the display color of the organic EL display. In addition, at wavelengths represented by 380nm, which cause damage such as degradation of several polymers used in organic EL displays, fading of pigments, and discoloration, it can achieve a light reduction rate of more than 95%, and can suppress the degradation of these polymers, fading of pigments, and discoloration.

[0125] Furthermore, with the aim of improving the durability (light resistance) of light-emitting elements in organic EL displays in recent years, and in order to protect the light-emitting elements, it is required to sufficiently reduce the light transmittance at wavelengths represented by 410 nm. The hard coating film of this invention can achieve a light reduction rate of 70.0% or more and 90.0% or less at a wavelength of 410 nm, thereby improving the durability (light resistance) of light-emitting elements in organic EL displays in recent years. It should be noted that when the light reduction rate at a wavelength of 410 nm exceeds 90.0%, b An increase in this value produces a yellowish tint, affecting the displayed colors of organic EL displays.

[0126] Furthermore, in order to ensure the display brightness of organic EL displays, it is required that the light reduction rate at a wavelength represented by 435nm in the visible light region be as small as possible. The hard coating film of the present invention can suppress the light reduction rate at a wavelength of 435nm in the visible light region to below 15.0%, which will not have an adverse effect on the display brightness of organic EL displays.

[0127] Furthermore, the hard coating film of the present invention is characterized in that, for the hard coating film, under an environment of 63°C and 50% relative humidity, the irradiance is set to 500 W / m. 2 After 100 hours of ultraviolet irradiation (light resistance test), the light reduction rate (%) at each wavelength calculated by the following formula 1 shall meet the following conditions (D) to (F).

[0128] Equation 1) Light reduction rate (%) at each wavelength = (transmittance of the transparent substrate itself at that wavelength - transmittance of the hard coating at that wavelength) / transmittance of the transparent substrate itself at that wavelength

[0129] (D) The light reduction rate at a wavelength of 380nm is over 95.0%.

[0130] The light reduction rate at a wavelength of (E)410nm is above 70.0% and below 90.0%.

[0131] The light reduction rate at (F)435nm wavelength is less than 15.0%.

[0132] It should be noted that the details of the above lightfastness test are described in the following examples.

[0133] For this purpose, the light reduction rate at the aforementioned wavelengths needs to maintain its optical performance after photosensitivity testing, at wavelengths represented by 380 nm (which causes damage such as degradation of several polymers, fading of pigments, and discoloration) and wavelengths represented by 410 nm (which helps protect the light-emitting elements of organic EL displays in recent years). The hard coating of this invention maintains the light reduction rate at wavelengths of 380 nm and 410 nm after photosensitivity testing, thus suppressing display degradation of organic EL displays. Furthermore, for the visible light region at a wavelength of 435 nm, the hard coating of this invention also suppresses the light reduction rate after photosensitivity testing, maintaining the display brightness of organic EL displays.

[0134] In this invention, the surface of the hard coating is measured at 1035 cm⁻¹ using an infrared spectrophotometer by combining a UV-curable resin with a silicone-based leveling agent and a UV absorber. -1 Peak intensity A and 1450 cm -1 Hard coatings with a peak intensity B ratio A / B of 1.46 or higher and less than 1.49 typically suffer from sink marks and seepage issues when using silicone-based leveling agents. However, according to the present invention, both issues of circular defects caused by sink marks during hard coating application and seepage spots caused by seepage of leveling agents can be solved simultaneously.

[0135] Furthermore, in this invention, a silicone-based leveling agent and an ultraviolet absorber are used together in the hard coating. In this case, the value defined by the concentration C (mass %) of the ultraviolet absorber contained in the hard coating × the film thickness D (μm) of the hard coating is preferably in the range of 0.65 (mass %·μm) or more and 1.38 (mass %·μm) or less. In this invention, it is particularly preferred to use a sesamol-type benzotriazole ultraviolet absorber together with a silicone-based leveling agent (especially low molecular weight siloxanes such as polyether-modified polydimethylsiloxane or polyester-modified polydimethylsiloxane).

[0136] As detailed above, according to the present invention, a hard coating film can be obtained in which the generation of circular defects caused by depressions during hard coating application and the generation of puffs caused by the exudation of leveling agents are suppressed, and the hard coating surface is free of defects and has a good appearance.

[0137] Furthermore, according to the present invention, a hard coating film can be obtained that, when used as a protective film on the surface of an organic EL display, does not adversely affect the display color or brightness of the organic EL display, and can improve the durability (light resistance) of the light-emitting elements of the organic EL display and suppress the display degradation of the organic EL display.

[0138] Furthermore, according to the present invention, it is possible to obtain a hard coating that maintains the above-mentioned properties even after a lightfastness test on the hard coating.

[0139] Example

[0140] Next, specific examples will be given to illustrate the implementation of the present invention, but the present invention is not limited to the following examples.

[0141] It should be noted that in the following description, "parts" means parts of mass unless otherwise specified, and "%" means mass unless otherwise specified.

[0142] (Example 1)

[0143] [Preparation of coating solution for hard coating formation]

[0144] Using 94 parts of an acrylic UV-curable resin coating containing a sesamol-type benzotriazole UV absorber (HFC-UVA-13 (trade name); manufactured by Harima Chemical Co., Ltd.; weight average molecular weight of the sesamol-type benzotriazole UV absorber: 22000) as the main agent, combined with 5 parts of Irgacure 184 (photopolymerization initiator, manufactured by BASF) and 1 part of polyester-modified polydimethylsiloxane (organosilicon leveling agent, BYK-313; manufactured by BYK Co., Ltd.), and diluted with toluene / propylene glycol monomethyl ether acetate = 15 / 85 (parts by weight), a coating liquid for hard coating formation with a final solids concentration of 30% was prepared (hereinafter also referred to as "coating for hard coating").

[0145] [Preparation of Hard Coating]

[0146] The aforementioned hard coating material was applied to one side of a 25 μm thick TJ25UL (manufactured by Fujifilm Corporation) triacetyl cellulose membrane using a rod coater. The membrane was then dried in a drying oven at 80°C for 1 minute using hot air to form a coating layer with a thickness of 3.0 μm. A UV irradiation device positioned 60 mm above the coating surface was used, with a UV irradiation dose of 100 mJ / cm².2 The coating was cured by ultraviolet radiation, thus producing the hard coating film of Example 1.

[0147] It should be noted that in this embodiment, the value defined by the ultraviolet absorber concentration C (mass%) × the film thickness D (μm) of the hard coating is 0.98.

[0148] (Example 2)

[0149] Except that the amount of the above-mentioned polyester-modified polydimethylsiloxane (organosilicon leveling agent, BYK-313; manufactured by BYK Corporation) was set to 0.7 parts, the hard coating film of Example 2 was prepared in the same manner as in Example 1 using the hard coating material prepared in the same manner as in Example 1.

[0150] (Example 3)

[0151] Except that the amount of the above-mentioned polyester-modified polydimethylsiloxane (organosilicon leveling agent, BYK-313; manufactured by BYK Corporation) was set to 0.5 parts, the hard coating film of Example 3 was prepared in the same manner as in Example 1 using the hard coating material prepared in the same manner as in Example 1.

[0152] (Example 4)

[0153] Except that the amount of the above-mentioned polyester-modified polydimethylsiloxane (organosilicon leveling agent, BYK-313; manufactured by BYK Corporation) was set to 0.4 parts, the hard coating film of Example 4 was prepared in the same manner as in Example 1 using the hard coating material prepared in the same manner as in Example 1.

[0154] (Example 5)

[0155] Except that the amount of the above-mentioned polyester-modified polydimethylsiloxane (organosilicon leveling agent, BYK-313; manufactured by BYK Corporation) was set to 0.3 parts, the hard coating film of Example 5 was prepared in the same manner as in Example 1 using the hard coating material prepared in the same manner as in Example 1.

[0156] (Comparative Example 1)

[0157] Except that the amount of the above-mentioned polyester-modified polydimethylsiloxane (organosilicon leveling agent, BYK-313; manufactured by BYK Corporation) was set to 1.5 parts, the hard coating film of Comparative Example 1 was prepared in the same manner as in Example 1 using a hard coating material prepared in the same manner as in Example 1.

[0158] (Comparative Example 2)

[0159] Except that the amount of the above-mentioned polyester-modified polydimethylsiloxane (organosilicon leveling agent, BYK-313; manufactured by BYK Corporation) was set to 0.2 parts, the hard coating film of Comparative Example 2 was prepared in the same manner as in Example 1 using the hard coating material prepared in the same manner as in Example 1.

[0160] (Comparative Example 3)

[0161] Except that the amount of the above-mentioned polyester-modified polydimethylsiloxane (organosilicon leveling agent, BYK-313; manufactured by BYK Corporation) was set to 0.1 parts, the hard coating film of Comparative Example 3 was prepared in the same manner as in Example 1 using the hard coating material prepared in the same manner as in Example 1.

[0162] (Comparative Example 4)

[0163] Except for the absence of the aforementioned sesamol-type benzotriazole UV absorber, the same hard coating material prepared in the same manner as in Example 1 was used to prepare the hard coating film of Comparative Example 4, which was also prepared in the same manner as in Example 1.

[0164] <Evaluation>

[0165] The following items were evaluated for each hard coating film of the above-prepared examples and comparative examples, and the results are summarized in Table 1.

[0166] <Infrared Spectrophotometric Measurement of Hard Coating Surfaces>

[0167] Using an infrared spectrophotometer (Spectrum 100, PerkinElmer), the ATR method was employed to determine and calculate the 1035 cm⁻¹ of the hard coating surface. -1 Peak intensity A and 1450 cm -1 The ratio of peak intensity B to peak intensity B, A / B.

[0168] <Evaluation of Exudation>

[0169] Perform visual inspection of the hard coating surface to confirm whether there are any spots. Mark ○ if there are no spots and × if there are spots.

[0170] <Defect Evaluation>

[0171] The surface of the hard coating was observed using an optical microscope (VHX-5000, manufactured by Keyence). In images taken at 50x magnification, covering an area of ​​3mm × 3mm or larger, the density of each 1mm area was measured. 2 The number of circular defects with a diameter of 30μm or more. The evaluation criterion is that if the number of defects is less than 5, it is considered acceptable.

[0172] In addition, in images of hard-coated surfaces taken at 50x magnification with an area of ​​3mm × 3mm or larger using an optical microscope, the area percentage (%) of circular defects with a diameter of 30μm or larger was measured. The evaluation criterion was that a defect area percentage of less than 10% was acceptable.

[0173] <Transmittance and light reduction rate at various wavelengths>

[0174] The transmittance of the hard coating at various wavelengths (380nm, 410nm, 435nm) was measured using a Hitachi High-Technologies U-3310 spectrophotometer. Measurements were performed in the wavelength range of 250–800nm ​​at a scan speed of 600nm / min. After measuring the transmittance at each wavelength, the "light reduction rate (%) at each wavelength" was calculated as shown in Formula 1 below.

[0175] Formula 1) Light reduction rate (%) at each wavelength = (Transmittance of the transparent substrate (the triacetyl cellulose membrane) at that wavelength - Transmittance of the hard coating at that wavelength) / Transmittance of the transparent substrate (the triacetyl cellulose membrane) at that wavelength

[0176] Value >

[0177] For each hard coating film prepared in the examples and comparative examples, b The values ​​were measured using a Hitachi High-Technologies U-3310 spectrophotometer.

[0178] <Lightfastness Test>

[0179] For each hard coating film prepared in the examples and comparative examples, an accelerated lightfastness test was performed using the Xenon Weather Ometer (performed according to JIS-K-5600-7-7, under the following conditions).

[0180] Light source: Xenon arc

[0181] Temperature: 63℃

[0182] Relative humidity: 50%

[0183] Irradiance: 50W / m 2

[0184] Irradiation time: 100 hours

[0185] Rainfall cycle and duration: Not specified.

[0186] It should be noted that the transmittance and light reduction rate of the hard coating film at various wavelengths after the lightfastness test were measured in the same manner as described above. ​

[0187] [Table 1]

[0188] As can be seen from the results in Table 1 above, the ratio A / B of the hard coating film in the embodiment of the present invention meets the scope of the present invention, and no exudation occurs. Furthermore, there are no problems with the generation of circular defects (number and area), which is acceptable. Typically, when using silicone-based leveling agents, issues such as sink marks and exudation arise. However, according to the present invention, a hard coating film with a defect-free surface and good appearance can be obtained, suppressing the generation of circular defects caused by sink marks during hard coating application and the generation of puff marks caused by exudation of the leveling agent.

[0189] Furthermore, the spectral characteristics (light reduction rate at each wavelength of 380nm, 410nm, and 435nm) of the hard coating film of the present invention satisfy the scope of the present invention (conditions (A) to (C)). Therefore, the hard coating film of the present invention can reduce the yellow tint index b... With a value suppressed below 5.0, it will not adversely affect the display color of the organic EL display. In addition, at wavelengths represented by 380nm, which cause damage such as degradation of several polymers used in organic EL displays, fading of pigments, and discoloration, it can achieve a light reduction rate of more than 95%, and can suppress the degradation of these polymers, fading of pigments, and discoloration.

[0190] Furthermore, with the aim of improving the durability (light resistance) of light-emitting elements in organic EL displays in recent years, and in order to protect the light-emitting elements, it is required to sufficiently reduce the light transmittance at wavelengths represented by 410 nm. The hard coating film of this invention can achieve a light reduction rate of 70.0% or more and 90.0% or less at a wavelength of 410 nm, thereby improving the durability (light resistance) of light-emitting elements in organic EL displays in recent years. It should be noted that when the light reduction rate at a wavelength of 410 nm exceeds 90.0%, b An increase in this value produces a yellowish tint, affecting the displayed colors of organic EL displays.

[0191] Furthermore, in order to ensure the display brightness of organic EL displays, it is required that the light reduction rate at a wavelength represented by 435nm in the visible light region be as small as possible. The hard coating film of the present invention can suppress the light reduction rate at a wavelength of 435nm in the visible light region to below 15.0%, which will not have an adverse effect on the display brightness of organic EL displays.

[0192] For this purpose, the light reduction rate at the aforementioned wavelengths needs to maintain its optical performance after photosensitivity testing, at wavelengths represented by 380 nm (which causes damage such as degradation of several polymers, fading of pigments, and discoloration) and wavelengths represented by 410 nm (which helps protect the light-emitting elements of organic EL displays in recent years). The hard coating of this invention maintains the light reduction rate at wavelengths of 380 nm and 410 nm after photosensitivity testing, thus suppressing display degradation of organic EL displays. Furthermore, for the visible light region at a wavelength of 435 nm, the hard coating of this invention also suppresses the light reduction rate after photosensitivity testing, maintaining the display brightness of organic EL displays.

[0193] On the other hand, in the hard coatings of Comparative Examples 1 to 3, where the ratio A / B described above does not satisfy the scope of the present invention, exudation occurs (Comparative Example 1), or a high number of circular defects are generated (Comparative Examples 2 and 3). That is, in the comparative examples, the problem of simultaneously suppressing the generation of exudation and the generation of circular defects cannot be solved. In addition, in the hard coating of Comparative Example 4, which does not use the ultraviolet absorber of the present invention, the light reduction rate at each wavelength is 0%, and the light is not reduced at all. Therefore, in particular, the transmittance at 410 nm cannot be sufficiently reduced, resulting in a problem of display degradation in organic EL displays.

Claims

1. A hard coating film, characterized in that, A hard coating containing a UV-curable resin, a silicone-based leveling agent, and a UV absorber is laminated on at least one side of a transparent substrate. The surface of the hard coating has a surface area of ​​1035 cm⁻¹ as measured by an infrared spectrophotometer. -1 Peak intensity A and 1450 cm -1 The ratio of peak intensity B to peak intensity B, A / B, is greater than 1.46 and less than 1.

49.

2. The hard coating film according to claim 1, characterized in that, The light reduction rate (%) of the hard coating at each wavelength, calculated by the following formula 1, satisfies the following conditions (A) to (C). Equation 1) Light reduction rate (%) at each wavelength = (transmittance of the transparent substrate itself at that wavelength - transmittance of the hard coating at that wavelength) / transmittance of the transparent substrate itself at that wavelength (A) The light reduction rate at a wavelength of 380nm is over 95.0%. (B) The light reduction rate at a wavelength of 410nm is above 70.0% and below 90.0%. (C) The light reduction rate at a wavelength of 435nm is less than 15.0%.

3. The hard coating film according to claim 1 or 2, characterized in that, The hard coating film b The value is below 5.

0.

4. The hard coating film according to claim 1 or 2, characterized in that, In images of the hard-coated surface taken using an optical microscope with a magnification of 50x and an area of ​​3mm × 3mm or larger, the number of circular defects with a diameter of 30μm or larger per 1mm is... 2 Less than 5.

5. The hard coating film according to claim 1 or 2, characterized in that, In an image of the hard coating surface taken with an optical microscope at 50x magnification, covering an area of ​​3mm × 3mm or larger, the area occupied by circular defects with a diameter of 30μm or larger is less than 10%.

6. The hard coating film according to claim 1 or 2, characterized in that, The organosilicon leveling agent is a polyether-modified polydimethylsiloxane or a polyester-modified polydimethylsiloxane.

7. The hard coating film according to claim 1 or 2, characterized in that, The amount of the silicone-based leveling agent is 0.3 to 1.4 parts by weight relative to 100 parts by weight of the UV-curable resin of the hard coating.

8. The hard coating film according to claim 1 or 2, characterized in that, The ultraviolet absorber is a sesamol-type benzotriazole ultraviolet absorber.

9. The hard coating film according to claim 8, characterized in that, The weight-average molecular weight of the sesamol-type benzotriazole UV absorber is in the range of 15,000 to 35,000.

10. The hard coating film according to claim 1 or 2, characterized in that, The value defined by the concentration C (mass %) of the ultraviolet absorber contained in the hard coating and the film thickness D (μm) of the hard coating is in the range of 0.65 (mass %·μm) or more and 1.38 (mass %·μm) or less.

11. The hard coating film according to claim 1 or 2, characterized in that, For the hard coating film, under an environment of 63°C and 50% relative humidity, the irradiance is set to 500 W / m. 2 After 100 hours of ultraviolet irradiation (lightfastness test), the light reduction rate (%) at each wavelength calculated by formula 1 meets the following conditions (D) to (F). Equation 1) Light reduction rate (%) at each wavelength = (transmittance of the transparent substrate itself at that wavelength - transmittance of the hard coating at that wavelength) / transmittance of the transparent substrate itself at that wavelength (D) The light reduction rate at a wavelength of 380nm is over 95.0%. (E) The light reduction rate at a wavelength of 410nm is above 70.0% and below 90.0%. The light reduction rate at (F)435nm wavelength is less than 15.0%.

12. The hard coating film according to claim 1 or 2, characterized in that, The transparent substrate is a triacetyl cellulose membrane, a polyethylene terephthalate membrane, or a cyclic olefin polymer membrane.

Images