Hard coating film

Abstract

The present invention provides a hard coat film which is excellent in visibility of a display while suppressing uneven brightness while maintaining good anti-glare properties. The hard coat film of the present invention has a hard coat layer containing organic fine particles and an ionizing radiation-curable resin on a transparent film. Furthermore, the difference between the refractive index (nx) of the ionizing radiation-curable resin and the refractive index (ny) of the organic fine particles (|nx-ny|) is 0.03 or greater.

Description

[0001] This application is a divisional application of Chinese invention patent application No. 201780077095.9 (international application No. PCT / JP2017 / 045227), with the Chinese national phase entry date of June 13, 2019 (international application date of December 16, 2017) and the invention title "Hard Coating Film". Technical Field

[0002] This invention relates to hard coatings. Background Technology

[0003] For laptop monitors, advancements in display technology have led to a leap in resolution. Laptops typically use anti-glare films to prevent external light such as fluorescent lamps and sunlight from entering the screen. However, with the increasing resolution of monitors, these anti-glare films can cause uneven brightness on the screen.

[0004] For example, for a hard coating film with a large surface roughness as proposed in Japanese Patent Application Publication No. 2002-185927 (Patent Document 1), although anti-glare properties are achieved, strong uneven brightness is generated due to the surface unevenness of the hard coating film, resulting in poor visibility.

[0005] On the other hand, in order to suppress uneven brightness, a design was considered to reduce surface roughness; however, the strong external light resulted in poor image visibility.

[0006] For example, the low-haze anti-glare film proposed in Japanese Patent Application Publication No. 2011-507167 (Patent Document 2) can suppress uneven brightness, but its anti-glare performance is low and the visibility of the image is reduced.

[0007] Existing technical documents

[0008] Patent documents

[0009] Patent Document 1: Japanese Patent Application Publication No. 2002-185927

[0010] Patent Document 2: Japanese Patent Application Publication No. 2011-507167 Summary of the Invention

[0011] The problem that the invention aims to solve

[0012] In existing technologies, when designing hard coatings to smooth out surface unevenness in order to suppress brightness uniformity, there are concerns that reduced anti-glare performance may lead to decreased visibility. Furthermore, while enhancing surface unevenness can improve anti-glare performance, this also results in decreased brightness uniformity.

[0013] Therefore, the objective of this invention is to provide a hard coating that can suppress brightness unevenness and improve the visibility of the display while maintaining good anti-glare properties.

[0014] Methods for solving problems

[0015] The inventors conducted in-depth research and found that the above-mentioned problems can be solved by having the following structure. That is, the present invention is a solution of the invention [1] to

[10] having the following structure.

[0016] [1] A hard coating film having a hard coating layer containing organic microparticles and an ionizing radiation curable resin on a transparent film, characterized in that the difference (|nx-ny|) between the refractive index (nx) of the ionizing radiation curable resin and the refractive index (ny) of the organic microparticles is 0.03 or more.

[0017] [2] A hard coating film having a hard coating layer containing organic microparticles and an ionizing radiation curable resin on a transparent film, characterized in that the difference (|nx-ny|) between the refractive index (nx) of the ionizing radiation curable resin and the refractive index (ny) of the organic microparticles is 0.03 or more, the haze value of the hard coating film is 5% or more and 50% or less, and the abrasion resistance load is 200g or more.

[0018] [3] The hard coating as described in [1] or [2] contains two or more organic microparticles with different average particle sizes, characterized in that the average particle size of the organic microparticle A containing the hard coating, which exhibits the largest average particle size, is 2 μm or more and 5 μm or less.

[0019] [4] The hard coating film as described in any one of [1] to [3] is characterized in that the average tilt angle of the unevenness of the surface of the hard coating film is less than 2.1 degrees.

[0020] [5] The hard coating film as described in any one of [1] to [4] is characterized in that, when the average height of the height in the evaluation area on the surface of the hard coating film is set to zero, the maximum cross-sectional height expressed as the difference between the maximum height and the minimum height in the evaluation area is 3.0 μm or less.

[0021] [6] The hard coating film as described in any one of [1] to [5] is characterized in that the diffuse reflectance of the hard coating film is 4.0% or less.

[0022] [7] The hard coating film as described in any one of [1] to [6] is characterized in that the transmission clarity of the hard coating film is 155% or more and 320% or less, and the gloss is 30% or more and 80% or less.

[0023] [8] The hard coating film as described in any one of [1] to [7] is characterized in that the haze value of the hard coating film is 8% or more and 35% or less, and the external haze value is 1% or more and 30% or less.

[0024] [9] The hard coating film as described in any one of [1] to [8] is characterized in that an anti-reflective layer containing a fluorine resin is laminated on the hard coating film.

[0025]

[10] The hard coating film as described in any one of [1] to [9] is characterized in that the above transparent film is a triacetyl cellulose film.

[0026] Invention Effects

[0027] According to the present invention, a hard coating film that can maintain good anti-glare properties and suppress uneven brightness, and provides good visibility of the display, can be provided. Detailed Implementation

[0028] The embodiments of the present invention will now be described in detail.

[0029] That is, the present invention relates to a hard coating film, which is a film having a hard coating layer containing organic microparticles and an ionizing radiation curable resin on a transparent film, characterized in that the difference (|nx-ny|) between the refractive index (nx) of the ionizing radiation curable resin and the refractive index (ny) of the organic microparticles is 0.03 or more.

[0030] The transparent film substrate that can be used in this invention is not particularly limited. For example, polyethylene terephthalate film (PET; refractive index 1.665), polycarbonate film (PC; refractive index 1.582), triacetyl cellulose film (TAC; refractive index 1.485), norbornene film (NB; refractive index 1.525) can be used. The film thickness is also not particularly limited, typically ranging from about 25 μm to about 250 μm. The refractive index of general ionizing radiation-cured resins is about 1.52. Therefore, to improve visibility, TAC film and NB film with refractive indices close to those of the aforementioned resins are preferred, with TAC film being particularly preferred. Furthermore, PET film is preferred in terms of price.

[0031] For the hard coating of the present invention, it is important to use an ionizing radiation curable resin in order to impart hardness (pencil hardness, scratch resistance) to the surface of the hard coating and to avoid the need for a large amount of heat when forming the hard coating.

[0032] Such ionizing radiation-curing resins can be appropriately selected from, for example, urethane acrylate resins, polyester acrylate resins, and epoxy acrylate resins. To obtain good adhesion to the transparent film substrate, preferred ionizing radiation-curing resins include those composed of ultraviolet-curable polyfunctional acrylates having two or more (meth)acryloyl groups within the molecule. Examples of UV-curable polyfunctional acrylates having two or more (meth)acryloyl groups within the molecule include: neopentyl glycol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, di(trimethylolpropane)tetra(meth)acrylate, pentaerythritol tetra(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol hexa(meth)acrylate, etc.; epoxy (meth)acrylates such as bisphenol A diglycidyl ether diacrylate, neopentyl glycol diglycidyl ether diacrylate, 1,6-hexanediol diglycidyl ether di(meth)acrylate; polyester (meth)acrylates that can be obtained by esterification of polyols with polycarboxylic acids and / or their anhydrides with acrylic acid; urethane (meth)acrylates obtained by reacting polyols, polyisocyanates, and hydroxyl-containing (meth)acrylates; and polysiloxane poly(meth)acrylates.

[0033] The aforementioned UV-curable multifunctional acrylates can be used alone or in combination of two or more, and their content is preferably 50-95% by weight relative to the resin solids content of the hard coating. It should be noted that, in addition to the aforementioned multifunctional (meth)acrylates, monofunctional acrylates such as 2-hydroxy methacrylate, 2-hydroxypropyl methacrylate, and glycidyl methacrylate, preferably 10% or less by weight relative to the resin solids content of the hard coating, can also be added.

[0034] Additionally, polymeric oligomers used to adjust hardness can be added to the hard coating. Examples of such oligomers include (meth)acrylate-terminated poly(meth)acrylate, styrene-terminated poly(meth)acrylate, (meth)acrylate-terminated polystyrene, (meth)acrylate-terminated polyethylene glycol, (meth)acrylate-terminated acrylonitrile-styrene copolymer, and (meth)acrylate-terminated styrene-methyl methacrylate copolymer, etc., and their content is preferably 5 to 50% by weight relative to the resin solids content in the coating for hard coating.

[0035] The refractive index (nx) of the ionizing radiation curable resin that forms such a hard coating is expressed as the average refractive index of all the ionizing radiation curable resins used in the hard coating after curing, preferably in the range of 1.50 to 1.55, and more preferably in the range of 1.51 to 1.53.

[0036] It is important that the hard coating of the present invention contains organic microparticles. The materials used to form these organic microparticles are not particularly limited, but examples include vinyl chloride resin (refractive index 1.53), acrylic resin (refractive index 1.49), (meth)acrylic resin (refractive index 1.52-1.53), polystyrene resin (refractive index 1.59), melamine resin (refractive index 1.57), polyethylene resin, polycarbonate resin, acrylic-styrene copolymer resin (refractive index 1.49-1.59), and silicone resin (refractive index 1.42).

[0037] Such organic microparticles preferably have an average particle size of 0.1–5 μm. When the average particle size is outside this range, it is difficult to achieve a balance between anti-glare properties and uneven brightness.

[0038] The organic microparticles of the present invention can use two or more organic microparticles with different average particle sizes.

[0039] The organic microparticles A contained in the hard coating, having the largest average particle size, preferably have an average particle size of 2 μm to 5 μm, more preferably 3 μm to 5 μm, and even more preferably 4 μm to 5 μm. When the average particle size of the organic microparticles A is within this range, it is easy to achieve a balance between anti-glare properties and brightness uniformity.

[0040] It should be noted that, in this invention, the average particle size refers to the average diameter of the particle length, which can be measured, for example, using a laser diffraction particle size analyzer SALD2200 (manufactured by Shimadzu Corporation).

[0041] Such organic microparticles A preferably contain 70 to 100 by weight relative to all organic microparticles contained in the hard coating.

[0042] Furthermore, relative to the average particle size of organic particles A, the average particle size of organic particles other than organic particles A contained in the hard coating is preferably 0.1 to 0.9 times, more preferably 0.4 to 0.7 times.

[0043] The refractive index (ny) of the organic microparticles in this invention refers to the average refractive index of all the organic microparticles contained in such a hard coating. It is important that the difference in refractive index (|nx-ny|) relative to the refractive index (nx) of the ionizing radiation-cured resin contained in the hard coating is 0.03 or more (it should be noted that |AA| indicates the absolute value AA). By ensuring that the difference in refractive index (|nx-ny|) meets this range, a balance between anti-glare and brightness uniformity can be achieved. The difference in refractive index (|nx-ny|) is preferably 0.05 or more, more preferably 0.07 or more, and even more preferably 0.09 or more. A difference of 0.1 or more is more likely to achieve the effects of this invention and is therefore preferred. The upper limit of the difference in refractive index (|nx-ny|) is preferably 0.2 or less, more preferably 0.15 or less.

[0044] Without altering the effects of the present invention, the hard coating of the present invention may further contain, as needed, leveling agents, defoamers, lubricants, ultraviolet absorbers, light stabilizers, polymerization inhibitors, wetting and dispersing agents, rheology control agents, antioxidants, antifouling agents, antistatic agents, conductive agents, etc.

[0045] The method for forming the hard coating of the present invention is not particularly limited. Known methods can be used, such as dispersing the above-mentioned ionizing radiation curable resin and the above-mentioned organic microparticles in a solvent and then coating the dispersed coating onto a transparent film and drying it to form the coating.

[0046] As a solvent, it can be appropriately selected based on the solubility of the aforementioned ionizing radiation-cured resin, as long as it is a solvent that can at least uniformly dissolve or disperse the solid components (ionizing radiation-cured resin, organic microparticles, and other additives). Examples of such solvents include ketones (acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, etc.), ethers (dioxane, tetrahydrofuran, etc.), aliphatic hydrocarbons (hexane, etc.), alicyclic hydrocarbons (cyclohexane, etc.), aromatic hydrocarbons (toluene, xylene, etc.), halogenated hydrocarbons (dichloromethane, dichloroethane, etc.), esters (methyl acetate, ethyl acetate, butyl acetate, etc.), alcohols (methanol, ethanol, isopropanol, butanol, cyclohexanol, etc.), cellosols (methyl cellosol, ethyl cellosol, etc.), cellosol acetate esters, sulfoxides, amides, etc. Furthermore, the solvent can be used alone or in combination.

[0047] There are no particular limitations on the coating method; coatings can be applied using techniques that allow for easy adjustment of the film thickness, such as gravure coating, microgravure coating, rod coating, slant die coating, slot die coating, and dip coating. It should be noted that the film thickness of the hard coating can be determined by observing cross-sectional photographs of the film using a microscope (e.g., scanning electron microscope, SEM) and by actually measuring the distance from the coating interface to the surface.

[0048] The hard coating of the present invention preferably has an average tilt angle of 2.1 degrees or less on its surface, more preferably 0.1 degrees or more and 1.8 degrees or less, and even more preferably 0.1 degrees or more and 1.5 degrees or less.

[0049] The aforementioned "average tilt angle" refers to the tilt angle of the line segment connecting the start and end points of the cross-sectional curve (measurement curve) of the membrane surface being measured, divided laterally at certain intervals ΔX. -1 The absolute value of (ΔYi / ΔX) is obtained by averaging this value.

[0050] By keeping the average tilt angle below 2.1 degrees, it is easier to achieve the effects of the present invention, namely, to maintain good anti-glare performance and suppress brightness unevenness, thereby obtaining high optical performance (visibility).

[0051] Furthermore, the maximum cross-sectional height (Rt) of the hard coating film of the present invention, when the average height of the evaluation area on its surface is set to zero, is preferably 3.0 μm or less, expressed as the difference between the maximum height and the minimum height in the evaluation area, and more preferably 2.0 μm or less.

[0052] Here, "maximum cross-sectional height," as defined above and as defined in JIS B0601, refers to the value calculated based on the cross-sectional curve (measurement curve) of the film surface being measured. The surface of a hard coating film containing microparticles and resin, as described in this invention, not only has a finely textured surface but also exhibits undulations. The measurement curve (often also called the cross-sectional curve) measured using a surface roughness measuring machine shows the following relationship between the undulation curve and the roughness curve: Cross-sectional curve = undulation curve + roughness curve Therefore, the "maximum cross-sectional height" in this invention is used to evaluate cross-sectional curves that include "surface undulation components". It should be noted that in JIS, the maximum cross-sectional height is represented by the symbol "Rt".

[0053] By keeping the maximum cross-sectional height below 3.0 μm, the invention exhibits a balanced and good anti-glare and brightness uniformity suppression effect. Furthermore, it also achieves an excellent balance with the hardness, which is important for hard coatings. Therefore, it is easier to obtain the effects of the present invention.

[0054] Furthermore, the hard coating of the present invention preferably has a diffuse reflectance of 4.0% or less, more preferably 3.0% or less.

[0055] In this invention, the diffuse reflectance refers to the value measured by the method described later, and is one of the indicators of anti-glare performance.

[0056] By reducing the diffuse reflectance to below 4.0%, it is easier to obtain the effects of the present invention, such as maintaining good anti-glare performance and suppressing brightness unevenness.

[0057] Furthermore, the hard coating film having the hard coating layer of the present invention obtained as described above preferably has a transmittance of 155% or more and 320% or less, more preferably 200% or more and 310% or less, and even more preferably 220% or more and 305% or less. In addition, the gloss is preferably 30% or more and 80% or less, more preferably 40% or more and 75% or less, and even more preferably 45% or more and 55% or less.

[0058] By bringing the above-mentioned transmission clarity and gloss within the above-mentioned range, the effects of the present invention can be more easily obtained.

[0059] Furthermore, the haze value of the hard coating film of the present invention is preferably 5% or more and 50% or less, more preferably 5% or more and 45% or less, even more preferably 5% or more and 40% or less, and particularly preferably 8% or more and 35% or less. The hard coating film of the present invention can suppress haze value to a certain extent and has good anti-glare properties, and can achieve a balance between anti-glare properties and brightness unevenness. In addition, the external haze value is preferably 1% or more and 30% or less.

[0060] Furthermore, the hard coating film of the present invention possesses excellent hardness on its hard coating surface. Specifically, the scratch resistance load measured by the method described later is 200g or more. That is, the hard coating film of the present invention can maintain good anti-glare properties, suppress uneven brightness, and has excellent hardness.

[0061] In the hard coating of the present invention, an anti-reflective layer may be further provided on the hard coating layer. As an anti-reflective layer, for example, the Y value in the tristimulus values ​​based on JIS Z 8701 is used as the reflectivity, and its reflectivity is preferably 2% or less.

[0062] It is important that such antireflective layers contain fluorinated resins. Examples of fluorinated resins include compounds having at least one polymerizable unsaturated double bond and at least one fluorine atom. Specific examples include (1) fluoroolefins such as tetrafluoroethylene, hexafluoropropylene, 3,3,3-trifluoropropylene, and chlorotrifluoroethylene; (2) alkyl perfluorovinyl ethers or alkoxyalkyl perfluorovinyl ethers; (3) perfluoro(alkyl vinyl ethers) such as perfluoro(methyl vinyl ether), perfluoro(ethyl vinyl ether), perfluoro(propyl vinyl ether), perfluoro(butyl vinyl ether), and perfluoro(isobutyl vinyl ether); (4) perfluoro(alkoxyalkyl vinyl ethers) such as perfluoro(propoxypropyl vinyl ether); (5) fluorinated (meth)acrylates such as trifluoroethyl methacrylate, tetrafluoropropyl methacrylate, octafluoropentyl methacrylate, and heptadecafluorodecyl methacrylate; and others. These compounds can be used alone or in combination of two or more. Specific examples include OPSTER TU2205 and OPSTER TU2276, which are coatings sold by JSR Corporation for forming anti-reflective films.

[0063] In the antireflective layer of the present invention, within a range that does not impede its effect, it may contain, as needed, the above-mentioned ionizing radiation curing resin, organic particles, inorganic particles, leveling agents, defoamers, lubricants, ultraviolet absorbers, light stabilizers, polymerization inhibitors, wetting and dispersing agents, rheology control agents, antioxidants, antifouling agents, antistatic agents, conductive agents, etc.

[0064] The thickness of the antireflective layer of the present invention is typically about 80 nm to about 120 nm, without particular limitation, and can be appropriately adjusted according to the application of the antireflective film. For example, in applications where reflectivity and hue are important, it is generally adjusted to 80 to 100 nm, while in applications where reflectivity is more important than hue, it is generally adjusted to 90 to 120 nm.

[0065] As explained above, the hard coating of the present invention, within the aforementioned range, specifically setting the difference (|nx-ny|) between the refractive index (nx) of the ionizing radiation-cured resin contained in the hard coating layer and the refractive index (ny) of the organic microparticles, can achieve a balance between good brightness unevenness suppression and good anti-glare performance. That is, it is presumed that the excellent effect of the hard coating of the present invention is due to the suppression of brightness unevenness caused by internal haze, and the ability to evenly balance anti-glare performance through surface irregularities, resulting in a hard coating that maintains good anti-glare performance, suppresses brightness unevenness, and provides good display visibility. Furthermore, the hard coating of the present invention further achieves the effects of the present invention by adjusting the average particle size, addition rate, refractive index, and film thickness of the added organic microparticles, thus suppressing brightness unevenness caused by internal haze and evenly balancing anti-glare performance through surface irregularities.

[0066] Example

[0067] The embodiments of the present invention will be described in more detail below through examples; however, the present invention is not limited to these embodiments without departing from the spirit of the invention. It should be noted that, unless otherwise specified, "parts" and "%" in the following description refer to parts by weight and percentage by weight, respectively.

[0068] [Example 1]

[0069] <Preparation of Hard Coatings>

[0070] 2.8 parts of silica microparticles (average particle size 4.5 μm, refractive index 1.42) manufactured by Momentive Performance Materials Japan Co., Ltd. as organic microparticle A, and 1.2 parts of the same silica microparticles (average particle size 2.0 μm, refractive index 1.42) as organic microparticle B, were added to 50 parts of toluene, and the mixture was stirred thoroughly after adding an appropriate amount of dispersant (manufactured by BYK-Chemie Co., Ltd.). 33 parts of an ionizing radiation curable resin (urethane acrylate manufactured by Arakawa Chemical Co., Ltd., acryloyl group number: 12, refractive index: 1.52) and an appropriate amount of Irgacure 184 (manufactured by BASF, photopolymerization initiator) were added to the liquid, and the mixture was stirred thoroughly to prepare a hard coating coating 1.

[0071] <Hard Coating Application>

[0072] The aforementioned hard coating 1 was applied to a 40 μm thick TAC membrane (triacetyl cellulose membrane) using a Mayer rod, dried at 80°C for 1 minute, and then irradiated at 200 mJ / cm² in an atmospheric atmosphere. 2 The ultraviolet light (light source: UV lamp manufactured by Fusion Japan) is used to cure the coating, resulting in a hard coating film 1.

[0073] [Example 2]

[0074] In the hard coating 1 of Example 1, 2.0 parts of silicon microparticles (average particle size 4.5 μm, refractive index 1.42) manufactured by Momentive Performance Materials Japan Co., Ltd. were added as organic microparticles A, and organic microparticles B were not used. Otherwise, the hard coating 2 was prepared in the same manner as in Example 1.

[0075] [Example 3]

[0076] <Layering of Anti-reflective Layers>

[0077] Add 72 parts of tert-butanol and 28 parts of OPSTER JUA204 (a fluoropolymer resin manufactured by JSR Corporation) to the anti-reflective coating and stir thoroughly to prepare the anti-reflective coating.

[0078] The antireflective layer was applied to the hard coating film 1 obtained in Example 1 using a Mayer rod, dried at 80°C for 1 minute, and then irradiated with 200 mJ / cm² under a nitrogen atmosphere. 2 Ultraviolet light was used to obtain an anti-reflective layer with a thickness of approximately 0.1 μm. This resulted in the hard coating film 3 of Example 3.

[0079] The hard coatings obtained in each embodiment were evaluated as described below, and the results are shown in Table 1.

[0080] (1) Refractive index of ionizing radiation cured resin

[0081] Add 33 parts of the ionizing radiation-curable resin used in Examples 1-3 and an appropriate amount of Irgacure 184 (manufactured by BASF, a photopolymerization initiator) to 50 parts of toluene, and stir thoroughly to obtain a resin dispersion. Coat the resin dispersion onto a 40 μm thick TAC film using a Mayer rod, dry at 80°C for 1 minute, and then irradiate under a nitrogen atmosphere at 200 mJ / cm². 2 By exposing the ultraviolet light to the material, a hard coating film A is obtained, which has a hard coating layer A consisting only of an ionizing radiation-curable resin.

[0082] Using the hard coating A side of the hard coating film A as the irradiation surface, the refractive index of the hard coating A was measured using a Filmetrics F20 (manufactured by Filmetrics), and was regarded as the refractive index of the ionizing radiation curing resin.

[0083] (2) Haze value

[0084] Measurements were performed using a haze meter, the "HM150," manufactured by the Murakami Color Technology Research Institute. The method for measuring internal haze is as follows: A TAC film was adhered to the hard coating side of the hard coating using a transparent adhesive, thereby disrupting the unevenness and making it flat. Measurements were then taken to eliminate the influence of surface shape on haze, and the internal haze was calculated. The external haze was then calculated by subtracting the internal haze value from the overall haze value.

[0085] (3) Shimmer (uneven brightness)

[0086] Various films were superimposed on a liquid crystal display (LCD) with a resolution of 227 ppi, displaying green across the entire surface. The degree of glare generation was visually evaluated. It should be noted that a transparent hard coating that does not produce glare was pre-applied to the LCD surface. A result of no glare was set to "5", and a result of strong glare was set to "1". The closer to "5", the less glare there is.

[0087] (4) Anti-glare

[0088] A black PET film is bonded to the opposite side of the hard coating. A fluorescent lamp is shone onto the hard coating. The state of the fluorescent lamp reflection, which is blurred and difficult to observe due to light scattering, is evaluated by visually evaluating the observation through the hard coating side. The result where the outline of the fluorescent lamp cannot be identified is set to "5", and the result where the outline is clearly reflected is set to "1". The closer to "5", the stronger the anti-glare performance.

[0089] (5) Transmission clarity

[0090] The measurements were performed using an image sharpness measuring instrument “ICM-1DP” manufactured by Suga Testing Machine Co., Ltd. Measurements were conducted using optical combs with widths of 2 mm, 1 mm, 0.5 mm, and 0.125 mm, and the measured values ​​for each width and their sum were calculated.

[0091] (6) Gloss (60 degrees)

[0092] Using a gloss meter (GM-3D) manufactured by Murakami Color Technology Research Institute, black polyvinyl chloride insulating tape (Nitto Vinyl tape, PROSELF No. 21 (wide width)) was pasted on the opposite side of the coating, and the gloss level was measured at 60 degrees.

[0093] [Table 1]

[0094] According to the results in Table 1, the hard coating film of the present invention can evenly suppress brightness unevenness and exhibit anti-glare properties caused by surface unevenness. Therefore, a hard coating film that can maintain good anti-glare properties, suppress brightness unevenness, and provide good visibility of the display can be obtained.

[0095] [Example 4]

[0096] <Preparation of Hard Coatings>

[0097] Add 7 parts of silicon microparticles (average particle size 4.5 μm, refractive index 1.43) manufactured by Momentive Performance Materials Japan Co., Ltd. as organic microparticle A, and 3 parts of the same silicon microparticles (average particle size 2.0 μm, refractive index 1.43) as organic microparticle B to 50 parts of toluene, and add 30% of a dispersant (BYK-170 manufactured by BYK-Chemie Co., Ltd.) and stir thoroughly. Add 33 parts of ionizing radiation curable resin (urethane acrylate manufactured by Arakawa Chemical Co., Ltd., acryloyl group number: 12, refractive index: 1.52) and 5% of Irgacure 184 (manufactured by BASF, photopolymerization initiator) relative to the resin to the liquid, and further add 2.5% of hindered amine light stabilizer (Tinuvin 292) relative to the solid content and 0.5% of fluorinated leveling agent (manufactured by DIC, RS-75) relative to the solid content, and stir thoroughly to prepare a hard coating coating (solid content concentration 36%).

[0098] <Hard Coating Application>

[0099] The aforementioned hard coating was applied to a 40 μm thick TAC (triacetyl cellulose) membrane using a Mayer rod, dried at 80°C for 1 minute, and then irradiated with 200 mJ / cm² under atmospheric conditions. 2 The coating was cured by ultraviolet light (light source: UV lamp manufactured by Fusion Japan) to obtain the hard coating film of Example 4. It should be noted that the coating thickness (measured by SEM) and coating amount of the hard coating are shown in Table 2.

[0100] [Example 5]

[0101] In the hard coating of Example 4, the amount of organic microparticle A added was 5 parts, and organic microparticle B was not used. Otherwise, it was prepared in the same manner as in Example 4 to obtain the hard coating of Example 5.

[0102] [Example 6]

[0103] In the hard coating of Example 4, the leveling agent was changed to a siloxane leveling agent (BYK-Chemie, BKK-UV3510), and 0.25% of the solid content was added. Otherwise, it was prepared in the same manner as in Example 4 to obtain a hard coating film.

[0104] Using a Mayer rod, an antireflective coating was applied to the obtained hard coating film, containing 72g of tert-butanol and 28g of OPSTER TU2276 (a fluoropolymer resin, manufactured by JSR Corporation, refractive index 1.35), and the mixture was thoroughly stirred. After drying at 80°C for 1 minute, the coating was irradiated with 200mJ / cm² under a nitrogen atmosphere.2 The film is cured by ultraviolet light to obtain an antireflective film (the hard coating film of Example 6) with an antireflective layer of about 0.1 μm.

[0105] [Example 7]

[0106] In the hard coating of Example 5, the leveling agent was changed to a siloxane leveling agent (BYK-Chemie, BKK-UV3510), and 0.25% of the solid content was added. Otherwise, it was prepared in the same manner as in Example 5 to obtain a hard coating film.

[0107] An anti-reflective layer was formed on the obtained hard coating film in the same manner as in Example 6, resulting in an anti-reflective film (the hard coating film of Example 7).

[0108] [Example 8]

[0109] In the hard coating of Example 4, the amount of organic microparticle A added was 5 parts, the amount of organic microparticle B added was 4 parts, the leveling agent was changed to a siloxane leveling agent (manufactured by BYK-Chemie, BKK-UV3510), and 0.25% relative to the solid content was added. Otherwise, it was prepared in the same manner as in Example 4 to obtain a hard coating film.

[0110] An anti-reflective layer was formed on the obtained hard coating film in the same manner as in Example 6, resulting in an anti-reflective film (the hard coating film of Example 8).

[0111] [Example 9]

[0112] The organic microparticles A in Example 4 were replaced with silicon microparticles (average particle size 4.6 μm, refractive index 1.45) and the addition amount was 7 parts, resulting in a coating weight of 4.9 g / m². 2 Otherwise, it was prepared in the same manner as in Example 4 to obtain the hard coating film of Example 9.

[0113] [Example 10]

[0114] The organic microparticles A in Example 4 were replaced with silicon microparticles (average particle size 4.6 μm, refractive index 1.45) and the addition amount was 7 parts, resulting in a coating weight of 5.4 g / m². 2 Otherwise, it was prepared in the same manner as in Example 4 to obtain the hard coating film of Example 10.

[0115] [Example 11]

[0116] The organic microparticles A in Example 4 were replaced with microparticles composed of silicon and styrene acrylic acid (average particle size 4.8 μm, refractive index 1.47), and the addition amount was increased to 7 parts, resulting in a coating weight of 5.0 g / m². 2 Otherwise, it was prepared in the same manner as in Example 4 to obtain the hard coating film of Example 11.

[0117] [Example 12]

[0118] Using the hard coating material of Example 11, the coating amount was 6.1 g / m². 2 Otherwise, it was prepared in the same manner as in Example 11 to obtain the hard coating film of Example 12.

[0119] [Example 13]

[0120] The organic microparticles A in Example 4 were replaced with microparticles composed of silicon and styrene acrylic acid (average particle size 4.8 μm, refractive index 1.49), and the addition amount was increased to 7 parts, resulting in a coating weight of 5.9 g / m². 2 Otherwise, it was prepared in the same manner as in Example 4 to obtain the hard coating film of Example 13.

[0121] [Example 14]

[0122] The organic microparticles A in Example 4 were replaced with microparticles composed of silicon and styrene acrylic acid (average particle size 5.0 μm, refractive index 1.45) and the addition amount was 7 parts. Otherwise, the same process as in Example 4 was used to obtain the hard coating film of Example 14.

[0123] [Example 15]

[0124] Using the hard coating material of Example 14, the coating amount was 5.9 g / m². 2 Otherwise, it was prepared in the same manner as in Example 14 to obtain the hard coating film of Example 15.

[0125] [Example 16]

[0126] The organic microparticles A in Example 4 were replaced with microparticles composed of silicon and styrene acrylic acid (average particle size 5.0 μm, refractive index 1.47), and the addition amount was increased to 7 parts, resulting in a coating weight of 5.8 g / m². 2 Otherwise, it was prepared in the same manner as in Example 4 to obtain the hard coating of Example 16.

[0127] [Example 17]

[0128] The organic microparticles A in Example 4 were replaced with microparticles composed of silicon and styrene acrylic acid (average particle size 5.0 μm, refractive index 1.49), and the addition amount was increased to 7 parts, resulting in a coating weight of 5.0 g / m². 2 Otherwise, it was prepared in the same manner as in Example 4 to obtain the hard coating film of Example 17.

[0129] [Example 18]

[0130] Using the hard coating material of Example 17, the coating amount was 6.0 g / m². 2Otherwise, it was prepared in the same manner as in Example 17 to obtain the hard coating of Example 18.

[0131] [Comparative Example 1]

[0132] Add 5.5 parts of styrene acrylic microparticles (average particle size 5.0 μm, refractive index 1.52) as organic microparticle A, and 30% of a dispersant (BYK-170 manufactured by BYK-Chemie) to 50 parts of toluene, and stir thoroughly. Add 33 parts of an ionizing radiation curable resin (urethane acrylate manufactured by Arakawa Chemical Co., Ltd., acryloyl group number: 12, refractive index: 1.52) and 5% of Irgacure 184 (photopolymerization initiator manufactured by BASF) to the liquid, and further add 2.5% of a hindered amine light stabilizer (Tinuvin 292) and 0.25% of a fluorinated leveling agent (RS-75 manufactured by DIC) to the liquid, and stir thoroughly to prepare a hard coating coating (53% solids concentration). Next, the above-mentioned hard coating material (coating amount 10.0 g / m²) was applied to a 40 μm thick TAC membrane (triacetyl cellulose membrane) in the same manner as in Example 4. 2 ), thus obtaining the hard coating of Comparative Example 1.

[0133] [Comparative Example 2]

[0134] Using 40 parts of organic microparticles A (average particle size 4.0 μm, refractive index 1.52) as Comparative Example 1, and a hard coating coating (solids concentration 30%) containing 0.5% fluorine leveling agent (RS-75 manufactured by DIC) relative to the solids content, at 3.0 g / m 2 The coating was applied in the same manner as in Comparative Example 1, and a hard coating film of Comparative Example 2 was obtained.

[0135] [Comparative Example 3]

[0136] Comparative Example 1 used organic microparticles A containing 7 parts of acrylic styrene microparticles (average particle size 5.0 μm, refractive index 1.52), organic microparticles B containing 3 parts of silica microparticles (average particle size 2.0 μm, refractive index 1.43), and a hard coating coating (solids concentration 36%) containing 0.5% of a fluorinated leveling agent (DIC RS-75) relative to the solids content, at a concentration of 5.9 g / m². 2 The coating was applied in the same manner as in Comparative Example 1, and a hard coating film of Comparative Example 3 was obtained.

[0137] The physical property values ​​of the hard coatings obtained in the above embodiments and comparative examples are summarized in Table 2.

[0138] Furthermore, the hard coatings obtained in the above embodiments and comparative examples were evaluated as follows, and the results are summarized in Table 3.

[0139] It should be noted that the following terms "anti-glare", "dispersion", and "diffuse reflectance" are all used as indicators for evaluating anti-glare performance.

[0140] (1) Haze value

[0141] Measurements were taken using a haze meter, the "HM150," manufactured by the Murakami Color Technology Research Institute.

[0142] (2) Shimmering (uneven brightness)

[0143] Various films were superimposed on a liquid crystal display (LCD) with a resolution of 227 ppi and a full-screen green display. The degree of glare generation was visually evaluated. It should be noted that a transparent hard coating that does not produce glare was pre-applied to the LCD surface. The result of no glare was set as "5", and the result of strong glare was set as "1". The closer to "5", the less glare there is.

[0144] (3) Anti-glare

[0145] A black PET film is bonded to the opposite side of the hard coating. A fluorescent lamp is shone onto the hard coating. The state of the fluorescent lamp reflection, which is blurred and difficult to observe due to light scattering, is evaluated by visually evaluating the observation through the hard coating side. The result where the outline of the fluorescent lamp cannot be identified is set to "5", and the result where the outline is clearly reflected is set to "1". The closer to "5", the stronger the anti-glare performance.

[0146] (4) Transmission clarity

[0147] The measurements were performed using an image sharpness measuring instrument “ICM-1DP” manufactured by Suga Testing Machine Co., Ltd. Measurements were conducted using optical combs with widths of 2 mm, 1 mm, 0.5 mm, and 0.125 mm, and the measured values ​​for each width and their sum were calculated.

[0148] (5) Reflection sharpness

[0149] Image sharpness was measured at a reflection angle of 45° using an image sharpness measuring instrument “ICM-1DP” manufactured by Suga Testing Machine Co., Ltd. Measurements were performed using optical combs with widths of 2mm, 1mm, 0.5mm, and 0.125mm, and the measured values ​​for each width and their sum were calculated.

[0150] (6) Gloss (60 degrees)

[0151] Using a gloss meter (GM-3D) manufactured by Murakami Color Technology Research Institute, black polyvinyl chloride insulating tape (Nitto Vinyl tape, PROSELF No. 21 (wide width)) was pasted on the opposite side of the coating, and the gloss level was measured at 60 degrees.

[0152] (7) Maximum cross-sectional height

[0153] The measurements were performed using a three-dimensional surface roughness meter, "VertScan2.0," manufactured by Ryoka Systems Co., Ltd. The maximum cross-sectional height (Rt) was calculated based on the difference between the maximum height (P) and the minimum height (V) within the evaluation area, when the average height (Ave) of the measured area cross-sectional curve parameters is zero. The measurement conditions were set as follows.

[0154] <Optical Conditions>

[0155] Camera: SONY HR-50 1 / 3 size

[0156] Objective lens: 10× (10x)

[0157] Tube: 1 × Main body

[0158] Relay: No relay

[0159] Filter: 530 White

[0160] ※Light intensity adjustment: Automatically implemented when the Lamp value falls within the range of 50 to 95.

[0161] <Measurement Conditions>

[0162] Pattern: Wave

[0163] Dimensions: 640×480

[0164] Range (μm): Start (5), Stop (-10)

[0165] (8) Mean tilt angle

[0166] The average tilt angle of the unevenness of the film surface was measured using the "VertScan2.0" three-dimensional surface roughness meter manufactured by Ryoka Systems Co., Ltd.

[0167] (9) Resistance to abrasion load

[0168] For each hard coating, apply a load to the hard coating surface with steel wool #0000 and rub it back and forth 10 times. Set the load at which damage begins to occur as the scratch-resistant load.

[0169] (10) Dispersion

[0170] Using a variable angle photometer (GC5000L) manufactured by Nippon Denshoku Kogyo Co., Ltd., light was irradiated onto the hard coating film surface at a projection angle of 60 degrees, and the photometric value of diffused light at a receiving angle from 40 degrees to 80 degrees was measured every 1 degree.

[0171] The value calculated using the following formula is used as the "dispersion".

[0172] Dispersion (%) = (t(60) / T) × 100

[0173] Here, t(60): photometric intensity measured at a positive reflection angle of 60 degrees.

[0174] T: The sum of photometric values ​​t(a) measured at each angle a degree.

[0175] T=t(40)+t(41) +…+t(79) +t(80)

[0176] (11) Diffuse reflectance (6° / de)

[0177] Using a Hitachi spectrophotometer (U-3310), incident light was incident on the hard coating surface at an angle of 6 degrees, and the diffuse reflectance of the light diffused on the hard coating surface was measured. A light collector was placed on the receiving surface at the point of positive reflection (reflection angle of 6 degrees). Therefore, positively reflected light is not included in this diffuse reflectance.

[0178]

[0179] [Table 3]

[0180] According to the results in Table 3, when using the hard coating film of the embodiments of the present invention, it is possible to balance the suppression of brightness unevenness and the anti-glare properties caused by surface unevenness. Therefore, a hard coating film that maintains good anti-glare properties (based on evaluations of anti-glare, dispersion, and diffuse reflectance) and suppresses brightness unevenness while maintaining good display visibility can be obtained. In addition, the hard coating film of the embodiments of the present invention can suppress haze values ​​to a certain extent and has excellent hardness (scratch resistance).

[0181] In contrast, the hard coating of the comparative example is difficult to balance suppressing uneven brightness and exhibiting poor anti-glare or hardness (scratch resistance) due to surface unevenness.

Claims

1. A hard coating film having a hard coating layer containing organic microparticles and an ionizing radiation-curable resin on a transparent film, characterized in that, The difference between the refractive index nx of the ionizing radiation-cured resin and the refractive index ny of the organic microparticles, |nx-ny|, is greater than 0.

03. The transparent membrane is a triacetylcellulose membrane.

2. The hard coating film according to claim 1, characterized in that, The haze value of the hard coating is 5% or more and 50% or less, and the abrasion resistance load is 200g or more.

3. The hard coating film according to claim 1 or 2, characterized in that, The haze value of the hard coating film is 8% or more and 35% or less, and the external haze value is 1% or more and 30% or less.

4. The hard coating film according to claim 1 or 2, comprising two or more organic microparticles with different average particle sizes, characterized in that, The average particle size of organic microparticles A, which exhibit the largest average particle size in the hard coating, is greater than 2 μm and less than 5 μm.

5. The hard coating film according to claim 1 or 2, characterized in that, The average tilt angle of the unevenness of the hard coating surface is less than 2.1 degrees.

6. The hard coating film according to claim 1 or 2, characterized in that, When the average height within the evaluation area of ​​the hard coating surface is set to zero, the maximum cross-sectional height, expressed as the difference between the maximum and minimum height within the evaluation area, is less than 3.0 μm.

7. The hard coating film according to claim 1 or 2, characterized in that, The diffuse reflectance of the hard coating is below 4.0%.

8. The hard coating film according to claim 1 or 2, characterized in that, The hard coating film has a transmission resolution of 155% or higher and 320% or lower, and a gloss of 30% or higher and 80% or lower.

9. The hard coating film according to claim 1 or 2, characterized in that, An anti-reflective layer containing fluorine resin is laminated on the hard coating.

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