Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J7/00—Chemical treatment or coating of shaped articles made of macromolecular substances
  • C08J7/04—Coating
  • C08J7/046—Forming abrasion-resistant coatings; Forming surface-hardening coatings
• • G—PHYSICS
  • G02—OPTICS
  • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
  • G02B1/00—Optical elements characterised by the material of which they are made; Optical coatings for optical elements
  • G02B1/10—Optical coatings produced by application to, or surface treatment of, optical elements
  • G02B1/14—Protective coatings, e.g. hard coatings
• • G—PHYSICS
  • G02—OPTICS
  • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
  • G02B5/00—Optical elements other than lenses
  • G02B5/20—Filters
  • G02B5/22—Absorbing filters

Definitions

• the present invention relates to a hard coat film used for optical components. More specifically, the present invention relates to a hard coat film that can be used as a protective film for panel displays such as organic electroluminescence (EL) displays, liquid crystal displays (LCDs), and plasma displays, and display device components such as touch panels.
• panel displays such as organic electroluminescence (EL) displays, liquid crystal displays (LCDs), and plasma displays
• display device components such as touch panels.
• the display surfaces of displays such as organic electroluminescence (EL) displays and liquid crystal displays (LCDs) are required to be scratch-resistant so that they do not get scratched during handling, reducing visibility.
• EL organic electroluminescence
• LCDs liquid crystal displays
• the hard coat film is required to satisfy a number of requirements, such as not adversely affecting the color and brightness of the display of the organic EL display, being able to improve the durability (light resistance) of the light-emitting element of the organic EL display, and being able to suppress deterioration of the display of the organic EL display.
• Patent Document 1 discloses a film-forming composition containing a triazine ring-containing polymer capable of forming a thin film with a high refractive index and excellent light resistance.
• Patent Document 2 discloses a film-forming composition containing a triazine ring-containing hyperbranched polymer capable of forming a film with high transparency and high light resistance and a thickness of 1000 nm or more.
• a near-ultraviolet absorber such as a sesamol-type benzotriazole-based ultraviolet absorber.
• adding such a near-ultraviolet absorber to a hard coat paint increases the surface tension, making it more likely for repelling to occur during coating, and resulting in numerous circular defects on the surface of the applied hard coat layer.
• a leveling agent is effective in adjusting the surface tension of hard coat paints.
• fluorine-based leveling agents due to costs and environmental impact, there has been a shift from fluorine-based leveling agents to silicone-based leveling agents as the leveling agents added to hard coat paints.
• conventional silicone-based leveling agents have a higher surface tension than fluorine-based leveling agents, making them more susceptible to repelling problems. In this case, it is possible to lower the surface tension by increasing the amount of leveling agent added, but increasing the amount of leveling agent added causes bleeding, creating a new problem of smearing on the surface of the hard coat layer after application.
• the object of the present invention is, first, to provide a hard coat film with good appearance and no defects on the surface of the hard coat layer by suppressing the occurrence of circular defects due to repelling during application of the hard coat and the occurrence of bleeding due to bleeding of the leveling agent; second, to provide a hard coat film that, when used as a protective film for the surface of an organic EL display, can improve the durability (light resistance) of the light-emitting element of the organic EL display without adversely affecting the color and brightness of the display of the organic EL display, and can suppress deterioration of the display of the organic EL display; and third, to provide a hard coat film that can maintain the above-mentioned performance even after the hard coat film is subjected to a light resistance test.
• the present invention has the following configuration.
• a hard coat film comprising a transparent substrate and a hard coat layer containing an ultraviolet curable resin, a silicone leveling agent and an ultraviolet absorber laminated on at least one surface of the substrate, the hard coat layer having a surface intensity A/B of a peak intensity B at 1450 cm -1 and a peak intensity A at 1035 cm- 1 as measured with an infrared spectrophotometer being 1.46 or more and less than 1.49.
• triacetyl cellulose film from the viewpoints of transparency, optical properties, and versatility in optical films for displays, among these film substrates, triacetyl cellulose film, polyethylene terephthalate film, cycloolefin polymer film, and the like are particularly suitable.
• the hard coat layer contains at least an ultraviolet curing resin, a silicone-based leveling agent, and an ultraviolet absorber.
• an ultraviolet-curable resin in particular, because it imparts surface hardness (pencil hardness, scratch resistance) to the hard coat layer and also makes it possible to adjust the degree of crosslinking by the amount of exposure to ultraviolet light, thereby enabling adjustment of the surface hardness of the hard coat layer.
• UV-curable polyfunctional acrylates having three or more (meth)acryloyloxy groups in 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 ethoxy triacrylate, glycerin propoxy triacrylate, and ditrimethylolpropane tetraacrylate.
• the multifunctional acrylate may be used alone or in combination of two or more types.
• the weight average molecular weight of the ultraviolet curing resin used in the hard coat layer is less than 1500, it is desirable that the number of functional groups in one molecule is 3 or more and less than 10. Furthermore, when the weight average molecular weight of the ultraviolet curing resin is 1500 or more, it is desirable that the number of functional groups in one molecule is 3 or more and less than 20. Within the above range, curling can be suppressed and appropriate processing suitability can be maintained.
• the ultraviolet absorber of the present invention is formed by reacting a sesamol-type benzotriazole monomer with, for example, an acrylate resin component to polymerize it.
• R1 represents a hydrogen atom or a methyl group
• R2 represents a linear or branched alkylene group having 1 to 6 carbon atoms, or a linear or branched oxyalkylene group having 1 to 6 carbon atoms.
• sesamol-type benzotriazole monomer represented by the above general formula (I) include 2-[2-(6-hydroxybenzo[1,3]dioxol-5-yl)-2H-benzotriazol-5-yl]ethyl methacrylate, 2-[2-(6-hydroxybenzo[1,3]dioxol-5-yl)-2H-benzotriazol-5-yl]ethyl acrylate, 3-[2-(6-hydroxybenzo[1,3]dioxol-5-yl)-2H-benzotriazol-5-yl]propyl methacrylate, 3-[2-(6-hydroxybenzo[1,3]dioxol-5-yl)-2H-benzotriazol-5-yl]propyl acrylate, 4-[2-(6-hydroxybenzo[1,3]dioxol-5-yl)-2H-benzotriazol-5-yl]butyl methacrylate, 4-[2-(6-hydroxy
• the ultraviolet absorber of the present invention can be obtained by polymerizing the above-mentioned sesamol-type benzotriazole monomer with other monomer components (e.g., acrylate resin components such as methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate, butyl (meth)acrylate, isobutyl (meth)acrylate, t-butyl (meth)acrylate, octyl (meth)acrylate, nonyl (meth)acrylate, etc.).
• the polymerization method can be a conventionally known solution polymerization method, emulsion polymerization method, suspension polymerization method, bulk polymerization method, etc.
• a sesamol-type benzotriazole-based ultraviolet absorber having a weight-average molecular weight in the range of 15,000 to 35,000 it is particularly preferable to use a sesamol-type benzotriazole-based ultraviolet absorber having a weight-average molecular weight in the range of 15,000 to 35,000.
• a sesamol-type benzotriazole-based ultraviolet absorber having a weight-average molecular weight of less than 15,000 is used, the light transmittance at 410 nm cannot be sufficiently reduced, resulting in a problem of degradation of the display of the organic EL display.
• the weight average molecular weight of the sesamol-type benzotriazole ultraviolet absorber is an average molecular weight obtained by gel permeation chromatography (GPC) analysis in terms of standard polystyrene.
• the ultraviolet absorbents of the present invention may be used alone or in combination of two or more kinds.
• other benzotriazole-based ultraviolet absorbents, hydroxyphenyltriazine-based ultraviolet absorbents, etc. may be used in combination as long as the effects of the present invention are not impaired.
• the hard coat film of the present invention in which the hard coat layer contains the above-mentioned ultraviolet absorber of the present invention, is able to satisfy the above conditions (A) to (C) in terms of its spectral characteristics (light reduction rate at wavelengths of 380 nm, 410 nm, and 435 nm).
• the thickness of the hard coat layer containing the ultraviolet absorber of the present invention is preferably more than 2.0 ⁇ m and less than 6.0 ⁇ m, and particularly preferably in the range of 3.0 ⁇ m to 5.0 ⁇ m.
• the blending amount of the ultraviolet absorber of the present invention is preferably in the range of 20 parts by mass to 60 parts by mass relative to 100 parts by mass of the ultraviolet curing resin of the hard coat layer.
• the blending amount of the ultraviolet absorber of the present invention is less than 20 parts by mass, the spectral characteristics of the present invention cannot be fully satisfied within the range of the thickness of the hard coat layer of the present invention more than 2.0 ⁇ m and less than 6.0 ⁇ m.
• the blending amount of the ultraviolet absorber of the present invention exceeds 60 parts by mass, the ratio of the ultraviolet curing resin in the hard coat layer decreases, so that the adhesion of the hard coat layer to the film substrate may decrease, or the hardness of the hard coat layer may decrease, which is not suitable.
• the blending amount of the ultraviolet absorber of the present invention is preferably in the range of 30 parts by mass to 50 parts by mass per 100 parts by mass of the ultraviolet curing resin of the hard coat layer.
• the relationship between the concentration of the ultraviolet absorber contained in the hard coat layer C (mass%) and the film thickness of the hard coat layer D ( ⁇ m) so that the relationship between the concentration of the ultraviolet absorber contained in the hard coat layer C (mass%) and the film thickness of the hard coat layer D ( ⁇ m) is in the range of 0.65 (mass%- ⁇ m) ⁇ C ⁇ D ⁇ 1.38 (mass%- ⁇ m).
• the concentration of the ultraviolet absorber contained in the hard coat layer C (mass%) and the film thickness of the hard coat layer D ( ⁇ m) so that the value defined by the concentration of the ultraviolet absorber contained in the hard coat layer C (mass%) ⁇ the film thickness of the hard coat layer D ( ⁇ m) is in the range of 0.65 (mass%- ⁇ m) or more and 1.38 (mass%- ⁇ m) or less.
• the C x D value is less than 0.65 (mass % / ⁇ m)
• the light transmittance at 410 nm cannot be sufficiently reduced, resulting in a problem of degradation of the display of the organic EL display.
• the C x D value exceeds 1.38 (mass % / ⁇ m)
• the adhesion of the hard coat layer to the film substrate decreases, which is not suitable.
• using an excessive amount of UV absorber is not suitable as it causes bleeding.
• the hard coat film of the present invention further contains a silicone-based leveling agent in the hard coat layer.
• a silicone-based leveling agent used in the present 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.
• the amount of the silicone leveling agent is preferably 0.3 parts by mass to 1.4 parts by mass with respect to 100 parts by mass of the ultraviolet curable resin of the hard coat layer.
• the average particle diameter of the inorganic oxide fine particles is preferably in the range of 5 to 50 nm, and more preferably in the range of 10 to 40 nm. If the average particle diameter is less than 5 nm, it is difficult to obtain sufficient surface hardness. On the other hand, if the average particle diameter exceeds 50 nm, the gloss and transparency of the hard coat layer are likely to decrease, and there is also a risk of the flexibility decreasing.
• examples of the inorganic oxide fine particles include alumina and silica.
• alumina which is mainly composed of aluminum, is particularly suitable because it has high hardness and can be effective with a smaller amount added than silica.
• the content of inorganic oxide fine particles is preferably 0.1 to 10.0 parts by mass per 100 parts by mass of the ultraviolet-curable resin of the hard coat layer. If the content of inorganic oxide fine particles is less than 0.1 parts by mass, it is difficult to obtain an effect of improving the surface hardness (scratch resistance). On the other hand, if the content exceeds 10.0 parts by mass, the haze increases, which is not preferable.
• the hard coat coating material for forming the hard coat layer may contain a photopolymerization initiator.
• a photopolymerization initiator acetophenones such as IRGACURE 651 and IRGACURE 184 (both trade names: manufactured by BASF) or benzophenones such as IRGACURE 500 (trade name: manufactured by BASF) may be used.
• additives that may be added to the hard coat layer as necessary include dyes (e.g., cyanine dyes, etc.), defoamers, surface tension regulators, antifouling agents, antioxidants, antistatic agents, light stabilizers, etc., within the scope of not impairing the effects of the present invention.
• dyes e.g., cyanine dyes, etc.
• defoamers e.g., cyanine dyes, etc.
• surface tension regulators e.g., antifouling agents, antioxidants, antistatic agents, light stabilizers, etc.
• the hard coat layer is formed by applying a hard coat coating material, which is prepared by dissolving and dispersing the above-mentioned UV-curable resin, the above-mentioned UV absorber, silicone leveling agent, photopolymerization initiator, and other additives in a suitable solvent, onto the transparent substrate, drying, and then curing by UV irradiation.
• a hard coat coating material which is prepared by dissolving and dispersing the above-mentioned UV-curable resin, the above-mentioned UV absorber, silicone leveling agent, photopolymerization initiator, and other additives in a suitable solvent.
• the solvent can be appropriately selected according to the solubility of the resin to be blended, and any solvent can be used as long as it can uniformly dissolve or disperse at least the solid content (resin, UV absorber, silicone leveling agent, photopolymerization initiator, other additives, etc.).
• solvents examples include known organic solvents such as aromatic 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, isopropyl alcohol, and n-propyl alcohol. These solvents can be used alone or in combination.
• aromatic solvents such as toluene, xylene, and n-heptane
• aliphatic solvents such as cyclohexane, methylcyclohe
• the method of applying the hard coat paint that forms the hard coat layer is usually applied by a known coating method such as gravure coating, microgravure coating, fountain bar coating, slide die coating, slot die coating, screen printing, or spray coating, and then dried at a temperature of about 50 to 120°C.
• the amount of ultraviolet (UV) light irradiated after the hard coat layer is formed may be any amount necessary to provide the hard coat layer with sufficient hardness, and can be set appropriately depending on the type of UV-curable resin, etc.
• the thickness (coating film thickness) of the hard coat layer is, for example, preferably more than 2.0 ⁇ m and less than 6.0 ⁇ m, and more preferably in the range of 3.0 ⁇ m to 5.0 ⁇ m. If the thickness of the hard coat layer is less than 2.0 ⁇ m, the necessary hardness (e.g., scratch resistance) is reduced, which is not preferable. On the other hand, if the thickness of the hard coat layer is 6.0 ⁇ m or more, curling is likely to occur, which reduces the handling property in the manufacturing process, and is also not preferable from the viewpoint of thinning the hard coat film.
• the thickness of the hard coat layer may be adjusted in relation to the concentration of the ultraviolet absorber so that the relationship between the concentration C (mass%) of the ultraviolet absorber contained in the hard coat layer and the thickness D ( ⁇ m) of the hard coat layer is in the range of 0.65 (mass% ⁇ m) ⁇ C ⁇ D ⁇ 1.38 (mass% ⁇ m), that is, the value defined as the concentration C (mass%) of the ultraviolet absorber contained in the hard coat layer ⁇ thickness D ( ⁇ m) of the hard coat layer is in the range of 0.65 (mass% ⁇ m) or more and 1.38 (mass% ⁇ m) or less.
• the hard coat film of the present invention is formed by laminating the above-mentioned hard coat layer on at least one side of a transparent substrate.
• a transparent substrate For example, when a cycloolefin polymer film is used as the transparent substrate, it is also preferable to provide an easy-adhesion layer between the transparent substrate and the hard coat layer in order to improve the adhesion of the hard coat layer.
• the resin used in the easy-adhesion layer can be any resin that forms a coating, without any particular restrictions.
• polyolefin-based resins acrylic resins such as styrene-acrylic resins and methyl methacrylate resins, epoxy-based resins, isocyanate-based resins, cellulose-based resins, or mixtures of two or more of these resins can be preferably used.
• the coating thickness of the easy-adhesion layer is not particularly limited, but is preferably in the range of 0.1 ⁇ m to 5.0 ⁇ m, which does not adversely affect the adhesion to the base film and the hard coat layer, or the pencil hardness of the hard coat layer.
• the hard coat film of the present invention is formed by laminating a hard coat layer containing an ultraviolet curable resin, a silicone-based leveling agent, and an ultraviolet absorber on at least one side of a transparent substrate.
• the hard coat film of the present invention is characterized in that the ratio A/B of the peak intensity A at 1035 cm ⁇ 1 to the peak intensity B at 1450 cm ⁇ 1 on the surface of the hard coat layer measured with an infrared spectrophotometer is 1.46 or more and less than 1.49.
• the ratio A/B satisfies the above range of the present invention, it is possible to suppress both the occurrence of circular defects due to repelling during application of the hard coat and the occurrence of blurring due to bleeding of the leveling agent.
• the peak intensity A at 1035 cm ⁇ 1 measured by an infrared spectrophotometer is due to the stretching vibration of Si—O and residues that contribute to cissing suppression in the siloxane-based leveling agent such as the polyether-modified polydimethylsiloxane and polyester-modified polydimethylsiloxane.
• the peak intensity B at 1450 cm ⁇ 1 is due to the deformation vibration of C—H and the main skeleton of the ultraviolet curable resin that does not contribute to cissing suppression.
• the ratio A/B of the peak intensity A at 1035 cm ⁇ 1 to the peak intensity B at 1450 cm ⁇ 1 is the ratio of residues that contribute to cissing suppression in the hard coat paint, and suggests that molecular motion due to Si—O stretching motion in particular is the cause of the bleeding and cissing suppression effect.
• an evaluation criterion for the occurrence of circular defects for example, in an image of the hard coat layer surface taken over an area of 3 mm x 3 mm or more with an optical microscope at a magnification of 50 times, if the number of circular defects of 30 ⁇ m or more in diameter is less than 5 per mm2, it is considered to be acceptable. In addition, in an image of the hard coat layer surface taken over an area of 3 mm x 3 mm or more with an optical microscope at a magnification of 50 times, if the area occupied by circular defects of 30 ⁇ m or more in diameter is less than 10%, it is considered to be acceptable.
• ratio A/B is less than 1.46, circular defects are likely to occur, and if the ratio A/B is 1.49 or more, bleeding due to bleeding of the leveling agent is likely to occur. In either case, if the ratio A/B is outside the range of the present invention, it is not possible to suppress either the occurrence of circular defects due to repelling during hard coat application or the occurrence of bleeding due to bleeding of the leveling agent.
• the hard coat film of the present invention is also characterized by a b* value of 5.0 or less.
• the b* value is 4.3 or less.
• the hard coat film of the present invention thus suppresses the b* value, an index of yellowness, to 5.0 or less, without adversely affecting the color displayed on the organic EL display, and achieves a light reduction rate of 95% or more at wavelengths such as 380 nm, which are known to cause damage such as deterioration of some polymers used in organic EL displays and fading and discoloration of dyes, thereby suppressing damage such as deterioration of these polymers and fading and discoloration of dyes.
• the hard coat film of the present invention can obtain a light reduction rate at a wavelength of 410 nm of 70.0% or more and 90.0% or less, and can improve the durability (light resistance) of the light emitting element of the recent organic EL display. Note that, if the light reduction rate at a wavelength of 410 nm exceeds 90.0%, the b* value increases and a yellowish tinge occurs, which affects the display color of the organic EL display.
• the hard coat film of the present invention makes it possible to suppress the light reduction rate at a wavelength of 435 nm in the visible light region to 15.0% or less, and does not adversely affect the brightness of the display of an organic EL display.
• the light reduction rate at a wavelength of 380 nm is 95.0% or more.
• an ultraviolet curable resin, a silicone-based leveling agent, and an ultraviolet absorber are used in combination, and a hard coat layer is formed in which the ratio A/B of the peak intensity A at 1035 cm -1 to the peak intensity B at 1450 cm -1 , as measured on the surface of the hard coat layer with an infrared spectrophotometer, is 1.46 or more and less than 1.49.
• a silicone-based leveling agent when used, problems such as cissing and bleeding occur.
• both of the problems of the occurrence of circular defects due to cissing during application of the hard coat and the occurrence of bleeding due to bleeding of the leveling agent can be simultaneously solved.
• a silicone-based leveling agent and an ultraviolet absorber are used in combination in the hard coat layer.
• the value defined by the concentration C (mass %) of the ultraviolet absorber contained in the hard coat layer x the film thickness D ( ⁇ m) of the hard coat layer is in the range of 0.65 (mass % ⁇ m) or more and 1.38 (mass % ⁇ m) or less.
• a sesamol-type benzotriazole-based ultraviolet absorber in combination with a silicone-based leveling agent (particularly a low molecular weight siloxane such as polyether-modified polydimethylsiloxane or polyester-modified polydimethylsiloxane).
• Example 1 [Preparation of Coating Solution for Forming Hard Coat Layer]
• the present invention contains a sesamol-type benzotriazole-based ultraviolet absorbing agent.
• the weight average molecular weight of the sesamol-type benzotriazole-based ultraviolet absorbing agent is 22,000.
• the base material is 94 parts of an acrylate-based ultraviolet curing resin coating material.
• the base material is 5 parts of Irgacure 184 (photopolymerization initiator, manufactured by BASF Corporation), and 1 part of polyester-modified polydimethylsiloxane (silicone-based leveling agent, BYK-313, manufactured by BYK Corporation).
• Example 2 A hard coat coating material prepared in the same manner as in Example 1 was used, except that the amount of the polyester-modified polydimethylsiloxane (silicone-based leveling agent, BYK-313; manufactured by BYK Co., Ltd.) was 0.7 parts, and a hard coat film of Example 2 was produced in the same manner as in Example 1.
• the polyester-modified polydimethylsiloxane silicone-based leveling agent, BYK-313; manufactured by BYK Co., Ltd.
• Example 3 A hard coat coating material prepared in the same manner as in Example 1 was used, except that the amount of the polyester-modified polydimethylsiloxane (silicone-based leveling agent, BYK-313; manufactured by BYK Co., Ltd.) was 0.5 parts, and a hard coat film of Example 3 was produced in the same manner as in Example 1.
• the polyester-modified polydimethylsiloxane silicone-based leveling agent, BYK-313; manufactured by BYK Co., Ltd.
• Example 4 A hard coat coating material prepared in the same manner as in Example 1 was used, except that the amount of the polyester-modified polydimethylsiloxane (silicone-based leveling agent, BYK-313; manufactured by BYK Co., Ltd.) was 0.4 parts, and a hard coat film of Example 4 was produced in the same manner as in Example 1.
• the polyester-modified polydimethylsiloxane silicone-based leveling agent, BYK-313; manufactured by BYK Co., Ltd.
• Example 5 A hard coat coating material prepared in the same manner as in Example 1 was used, except that the amount of the polyester-modified polydimethylsiloxane (silicone-based leveling agent, BYK-313; manufactured by BYK Co., Ltd.) was 0.3 parts, and a hard coat film of Example 5 was produced in the same manner as in Example 1.
• the polyester-modified polydimethylsiloxane silicone-based leveling agent, BYK-313; manufactured by BYK Co., Ltd.
• Comparative Example 1 A hard coat coating material prepared in the same manner as in Example 1 was used, except that the amount of the polyester-modified polydimethylsiloxane (silicone-based leveling agent, BYK-313; manufactured by BYK Co., Ltd.) was 1.5 parts, and a hard coat film of Comparative Example 1 was produced in the same manner as in Example 1.
• the polyester-modified polydimethylsiloxane silicone-based leveling agent, BYK-313; manufactured by BYK Co., Ltd.
• Comparative Example 2 A hard coat coating material prepared in the same manner as in Example 1 was used, except that the amount of the polyester-modified polydimethylsiloxane (silicone-based leveling agent, BYK-313; manufactured by BYK Co., Ltd.) was 0.2 parts, and a hard coat film of Comparative Example 2 was produced in the same manner as in Example 1.
• the polyester-modified polydimethylsiloxane silicone-based leveling agent, BYK-313; manufactured by BYK Co., Ltd.
• Comparative Example 3 A hard coat coating material prepared in the same manner as in Example 1 was used, except that the amount of the polyester-modified polydimethylsiloxane (silicone-based leveling agent, BYK-313; manufactured by BYK Co., Ltd.) was 0.1 parts, and a hard coat film of Comparative Example 3 was produced in the same manner as in Example 1.
• the polyester-modified polydimethylsiloxane silicone-based leveling agent, BYK-313; manufactured by BYK Co., Ltd.
• Comparative Example 4 A hard coat film of Comparative Example 4 was produced in the same manner as in Example 1, using a hard coat coating material prepared in the same manner as in Example 1, except that the sesamol-type benzotriazole-based ultraviolet absorber was not added.
• Measurement was performed using an infrared spectrophotometer (Spectrum 100, manufactured by PerkinElmer) by the ATR method, and the ratio A/B of the peak intensity A at 1035 cm -1 to the peak intensity B at 1450 cm -1 measured on the hard coat layer surface by the infrared spectrophotometer was calculated.
• ⁇ Bleed occurrence evaluation> The appearance of the hard coat layer surface was observed to check for the presence or absence of bleeding, and the absence of bleeding was rated as ⁇ , and the presence of bleeding was rated as ⁇ .
• ⁇ Defect evaluation> The surface of the hard coat layer was observed with an optical microscope (VHX-5000, manufactured by Keyence Corporation), and the number of circular defects with a diameter of 30 ⁇ m or more per mm2 was measured using an image of an area of 3 mm ⁇ 3 mm or more photographed at a magnification of 50 times. The evaluation criteria was that the number of defects was less than 5, which was considered to be acceptable. Similarly, the surface of the hard coat layer was photographed with an optical microscope at a magnification of 50 times over an area of 3 mm ⁇ 3 mm or more, and the area ratio (%) of circular defects with a diameter of 30 ⁇ m or more was measured. The evaluation criterion was that the defect area ratio was less than 10%, which was considered to be acceptable.
• the light transmittance of the hard coat film at each wavelength was measured using a spectrophotometer U-3310 manufactured by Hitachi High-Technologies Corporation. The measurement was performed in the wavelength range of 250 to 800 nm at a scan speed of 600 nm/min. After measuring the light transmittance at each wavelength, the "light reduction rate (%) at each wavelength” was calculated as shown in the following formula 1.
• ⁇ b* value> The b* value was measured for each of the hard coat films prepared in the Examples and Comparative Examples using a spectrophotometer U-3310 manufactured by Hitachi High-Technologies Corporation.
• the light transmittance and light reduction rate of the hard coat film at each wavelength after the light resistance test were measured in the same manner as above.
• the hard coat film of the example of the present invention has a ratio A/B that satisfies the range of the present invention, and there is no bleeding. There are also no problems with the occurrence of circular defects (number and area), and the test passes. Normally, when a silicone-based leveling agent is used, problems such as repelling and bleeding occur, but according to the present invention, the occurrence of circular defects due to repelling during application of the hard coat and the occurrence of bleeding due to bleeding of the leveling agent are suppressed, and a hard coat film with a good appearance and no defects on the surface of the hard coat layer can be obtained.
• the hard coat film of the present invention has spectral characteristics (light reduction rate at wavelengths of 380 nm, 410 nm, and 435 nm) that satisfy the range of the present invention (conditions (A) to (C) above).
• the hard coat film of the present invention can suppress the b* value, which is an index of yellowness, to 5.0 or less, without adversely affecting the displayed color of the organic EL display, and can achieve a light reduction rate of 95% or more at wavelengths such as 380 nm, which causes damage such as deterioration of some polymers used in organic EL displays and fading and discoloration of dyes, thereby suppressing damage such as deterioration of these polymers and fading and discoloration of dyes.
• the hard coat film of the present invention can obtain a light reduction rate at a wavelength of 410 nm of 70.0% or more and 90.0% or less, thereby improving the durability (light resistance) of the light-emitting elements in recent organic EL displays. Note that, if the light reduction rate at a wavelength of 410 nm exceeds 90.0%, the b* value increases, causing a yellowish tint, which affects the display color of the organic EL display.
• the hard coat film of the present invention makes it possible to suppress the light reduction rate at a wavelength of 435 nm in the visible light region to 15.0% or less, and does not adversely affect the brightness of the display of an organic EL display.
• the light reduction rate at each of the above-mentioned wavelengths must maintain its optical performance even after light resistance testing at wavelengths such as 380 nm, which causes damage such as deterioration of some polymers and fading and discoloration of dyes, and at wavelengths such as 410 nm, which contributes to protecting the light-emitting elements of recent organic EL displays.
• the hard coat film of the present invention can maintain its light reduction rate at wavelengths of 380 nm and 410 nm even after light resistance testing, and can suppress deterioration of the display of the organic EL display. Furthermore, for the wavelength of 435 nm in the visible light region, the hard coat film of the present invention can suppress the light reduction rate even after light resistance testing, and can maintain the brightness of the display of the organic EL display.

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  • 2024-12-14 JP JP2025565331A patent/JPWO2025134957A1/ja active Pending
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