JP2013209482A - Hard coating composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hard coating composition forming a hard coat layer having high visibility and good hardness, and also having elongatability.SOLUTION: A hard coating composition contains (A) a phenol novolac acrylate having two or more acrylate groups, (B) an aromatic group-containing mono- or poly(meth)acrylate having 1 to 2 mol of a 2-3C alkylene oxide in the molecule, and (C) a fluorene skeleton-containing (meth)acrylate having two or more (meth)acrylate groups, wherein 100 pts.mass of the hard coating composition contains 40 to 70 pts.mass of the phenol novolac acrylate (A), 10 to 30 pts.mass of the (meth)acrylate (B), and 15 to 40 pts.mass of the fluorene skeleton-containing (meth)acrylate (C).

Description

  The present invention relates to a hard coating composition that provides a hard coat layer having high visibility and good hardness, and also has extensibility.

  Liquid crystal display devices (liquid crystal displays) have advantages such as thinness, light weight, and low power consumption, and are used in various fields such as computers, word processors, televisions, mobile phones, and portable information terminal devices. In these liquid crystal display devices, so-called touch panels having a mechanism for operating devices by holding down the display on the screen are rapidly spreading. Such a touch panel has, for example, a mobile phone such as a smartphone, a tablet PC, a personal digital assistant device, a bank ATM, a vending machine, a personal digital assistant (PDA), a copier, a facsimile machine, and a game machine due to its excellent operability. It is widely used in guidance display devices installed in facilities such as museums and department stores, car navigation systems, multimedia stations (multifunctional terminals installed in convenience stores), monitoring devices for railway vehicles, and the like.

  Generally in the touch panel, the transparent conductive laminated body which has the transparent conductive layer provided on the transparent base material is generally used. For the formation of the transparent conductive layer, indium-tin oxide (ITO) or the like is generally used.

  As a base film constituting a film having a transparent conductive layer, a film such as a PET film or a polycarbonate film is often used from the viewpoint of high transparency and price. These base films may be provided with a transparent hard coat layer for the purpose of improving scratch resistance and durability. On the other hand, there is a problem that interference fringes are generated by providing a transparent hard coat layer on a transparent substrate film. Generation | occurrence | production of this interference fringe brings about the fall of visibility.

  The generation of the interference fringes depends on the refractive index difference between the transparent base film and the transparent hard coat layer and the extremely slight variation in the film thickness of the transparent hard coat layer. The generation of such interference fringes is theoretically eliminated by completely eliminating variations in the film thickness of the transparent hard coat layer. However, such means are unrealistic in the current technology and are extremely difficult to implement.

  As another means for preventing the occurrence of interference fringes, there is a method of reducing the difference in refractive index between the refractive index of the transparent substrate film and the refractive index of the transparent hard coat layer. In such a method, conventionally, by including a high refractive index agent such as a metal oxide having a high refractive index in the transparent hard coat layer, the refractive index of the transparent hard coat layer is increased, and the transparent substrate film The method of making it approach the refractive index of was taken. For example, JP 2009-265590 A (Patent Document 1) discloses a hard coating agent using fine particles of metal oxide such as zirconia, titanium oxide, ITO, ATO, ZnO, tin oxide, and zinc antimonate as a high refractive index agent. Describes a method of adjusting the refractive index of the hard coat layer by blending into the hard coat layer. However, when a high refractive index agent such as a metal oxide is included in the transparent hard coat layer, there is a problem that the extensibility and flex resistance of the hard coat layer are lowered.

Japanese Patent Application Laid-Open No. 2002-241527 (Patent Document 2) describes a transparent hard coat layer-containing film having excellent visibility. And this patent document 2 has a reference about a high refractive index layer. The high refractive index layer in Patent Document 2 is formed by vapor deposition or sputtering of a metal oxide such as ZnO, TiO ₂ , CeO ₂ , SnO ₂ , ZrO ₂ , ITO, or the like. It is formed by dispersing in a binder resin (such as [0007] paragraph).

  Japanese Patent Application Laid-Open No. 2003-055607 (Patent Document 3) describes a coating material that is formed in layers on a transparent base body and in which interference fringes are not noticeable. This coating material is characterized in that the attenuation coefficient is adjusted by blending fine particles and / or pigments. Here, various metals, metal oxides, metal nitrides, metal carbides are listed as fine particles, and azo pigments, phthalocyanine pigments, anthraquinone pigments, quinacridone pigments, dioxane pigments, quinophthalone pigments are used as pigments. Pigments are mentioned (such as [0021] paragraph).

  These Patent Documents 1 to 3 disclose means for preventing the generation of interference fringes and improving the visibility. However, all of these Patent Documents 1 to 3 differ from the present invention in that a high refractive index agent such as a metal oxide is used.

  Japanese Patent Application Laid-Open No. 2007-292288 (Patent Document 4) describes an optical laminate in which the high refractive index hard coat layer contains a bromine-based resin (claim 1 and the like). This optical laminate is described as having improved optical characteristics, light resistance, hardware performance, and the like. On the other hand, the present invention does not use a brominated resin in increasing the refractive index of the hard coat layer, and the configuration of the invention is different from this invention.

  Japanese Patent Application Laid-Open No. 2008-239673 (Patent Document 5) describes a transparent cross-linked film obtained by curing and cross-linking a composition containing a vinyl ester composition, a polyfunctional acrylate and a (meth) acrylate having a fluorene skeleton. (Claim 1). This transparent crosslinked film is characterized by excellent surface hardness and no interference fringes. However, in this patent document 5, the test is performed under the condition of a film thickness of 50 μm. This film thickness is very high compared with the film thickness generally used in the field of hard coat layers. Therefore, there is a cost disadvantage. Moreover, the interference fringe generation | occurrence | production suppression effect in the crosslinked film obtained by the composition described in this patent document 5 has not reached the level currently calculated | required.

JP 2009-265590 A JP 2002-241527 A JP 2003-055607 A JP2007-29283A JP 2008-239673 A

  An object of the present invention is to solve the above-described problems of the prior art. More specifically, an object of the present invention is to provide a hard coating composition that forms a hard coat layer having high visibility and good hardness and also having extensibility.

The present invention
(A) a phenol novolac acrylate having 2 or more acrylate groups,
(B) an aromatic group-containing mono- or poly (meth) acrylate compound having an alkylene oxide structure of 2 or 3 carbon atoms in the molecule, and (C) 2 or more (meth) acrylate groups Fluorene skeleton-containing (meth) acrylate,
A hard coating composition comprising:
The phenol novolac acrylate (A) is 40 to 70 parts by mass, the (meth) acrylate (B) is 10 to 30 parts by mass and the fluorene skeleton is contained (meta) with respect to 100 parts by mass of the resin component contained in the hard coating composition. ) Acrylate (C) is contained in 15-40 parts by mass,
A hard coating composition is provided, which solves the above problems.

  The phenol novolac acrylate (A) has the following formula (I)

（Ｉ）

(I)

[In Formula (I), R ¹ is H or CH ₂ OH, R ² is H or OH, n is 2 to 5, and m is 0 to 5. ]
It is more preferable that it is a compound shown by these.

  The (meth) acrylate (B) is more preferably an aromatic group-containing (meth) acrylate having a refractive index in the range of 1.56 to 1.64.

  The fluorene skeleton-containing (meth) acrylate (C) is represented by the following formula (II)

（II）

(II)

[In Formula (II), each R ³ is independently H or CH ₃ ;
R ⁴ is a -A-OC (O) CR = CH 2, A is _{independently, -OCH 2 CH 2 -, -} OCH 2 CH 2 CH 2 -, - OCH (CH 3) CH 2 - or -OCH ₂ CH (CH ₃₎ - and is, R is H or CH ₃ independently. ]
It is more preferable that it is a compound shown by these.

Further, the hard coating _{composition, ZnO, TiO 2, CeO 2} , SnO 2, ZrO 2 , and indium - More preferably the total content of tin oxide is not more than 0.0001 wt% in the composition.

The present invention also provides
A transparent polymer substrate, and
A hard coat layer formed by coating the hard coating composition on a substrate;
A hard coat film having
The hard coat layer has a refractive index of 1.565 to 1.620,
A hard coat film is also provided.

  The thickness of the hard coat layer is more preferably 0.05 to 10 μm.

The hard coat film is
The substrate is a PET film having a thickness of 20 to 300 μm,
More preferably, the hard coat film is characterized in that no crack is generated in the hard coat layer when the film is stretched 15% in the MD direction at 20 ° C. under the condition of a pulling speed of 5 mm / sec.

The hard coat film is
The substrate is a polycarbonate film having a thickness of 30 to 200 μm,
More preferably, the hard coat film is characterized in that cracks do not occur in any of the hard coat layer and the substrate when bent at 180 ° under the conditions of 25 ° C. and 60 degrees / second.

  The present invention also provides a transparent conductive laminate in which a transparent conductive layer is formed on at least one surface of the hard coat film. More preferably, the transparent conductive layer is a crystalline layer containing indium oxide, and the thickness of the transparent conductive layer is 5 to 50 nm.

  Further, it is more preferable that a metal oxide layer is present between the hard coat layer and the transparent conductive layer, and the thickness of the metal oxide layer is 0.5 to 5.0 nm.

  The present invention also provides a touch panel having the transparent conductive laminate.

The hard coating composition of the present invention provides a transparent hard coat layer provided on a transparent polymer substrate. The transparent hard coat layer formed by the hard coating composition of the present invention is characterized by having good hardness and high visibility and extensibility. The transparent hard coat layer formed by the hard coating composition of the present invention has a high refractive index. Therefore, even when the transparent hard coat layer in the present invention is provided on a base film having a high refractive index such as a PET film or a polycarbonate film, there is an advantage that no interference fringes are generated.
The hard coating composition of the present invention is further characterized by having a high refractive index without containing a high refractive index agent such as a metal oxide. Therefore, the obtained transparent hard coat layer is characterized by having high extensibility in addition to high hardness and refractive index.
By using the hard coating composition of the present invention, even when a transparent hard coat layer is formed on a base film having a high refractive index such as a PET film or a polycarbonate film, it has high visibility and good hardness. In addition, there is an advantage that a hard coat layer having extensibility is provided.

It is a graph which shows the transmission spectrum (transmittance (%)) in the wavelength range of 400-800 nm of the hard-coat layer obtained using the hard-coating composition of Example 1. It is a graph which shows the transmission spectrum (transmittance (%)) in the wavelength range of 400-800 nm of the hard-coat layer obtained using the hard-coating composition of the comparative example 10.

Hard coating composition The hard coating composition of the present invention comprises:
(A) a phenol novolac acrylate having 2 or more acrylate groups,
(B) an aromatic group-containing mono- or poly (meth) acrylate compound having an alkylene oxide structure of 2 or 3 carbon atoms in the molecule, and (C) 2 or more (meth) acrylate groups Fluorene skeleton-containing (meth) acrylate,
including. And with respect to 100 mass parts of resin components contained in the hard coating composition, phenol novolac acrylate (A) is 40-70 mass parts, (meth) acrylate (B) is 10-30 mass parts and contains a fluorene skeleton. (Meth) acrylate (C) is contained in an amount of 15 to 40 parts by mass.

(A) Phenol novolac acrylate having 2 or more acrylate groups The hard coating composition of the present invention comprises (A) a phenol novolac acrylate having 2 or more acrylate groups. When the hard coating composition contains the phenol novolac acrylate (A), the resulting hard coat layer becomes a high refractive index layer that is transparent and has high hardness. Thereby, generation | occurrence | production of an interference fringe can be prevented effectively.

  The phenol novolac acrylate (A) has the following formula (I)

（Ｉ）

(I)

[In Formula (I), R ¹ is H or CH ₂ OH, R ² is H or OH, n is 2 to 5, and m is 0 to 5. ]
It is preferable that it is a phenol novolak-type acrylate shown by these. In said formula (I), it is more preferable that n is 2-4 and m is 0-3, n is 2-4, and it is still more preferable that m is 0-1.

  The weight average molecular weight of the phenol novolac acrylate (A) is preferably 400 to 2500, and more preferably 450 to 2000. The hydroxyl value of the phenol novolac acrylate (A) is preferably 100 to 180 mgKOH / g, and more preferably 120 to 160 mgKOH / g.

  In this specification, the weight average molecular weight of each component can be measured by a gel permeation chromatography method. In the measurement of the weight average molecular weight, a high-speed GPC apparatus such as HLC-8220 GPC (manufactured by Tosoh Corporation) can be used. As a specific measurement condition of weight average molecular weight using HLC-8220GPC (manufactured by Tosoh Corporation), 2 g of a test sample was weighed and treated in a vacuum dryer at 40 ° C. for 2 hours to remove moisture, and then a THF solution. And a measurement is performed under the conditions of a column injection amount: 10 μl and a flow rate: 0.35 ml / min.

  The said phenol novolak-type acrylate (A) is on condition that 40-70 mass parts is contained with respect to 100 mass parts of resin components contained in a hard-coating composition. When the amount of the phenol novolac acrylate (A) is less than 40 parts by mass and when the amount of the phenol novolac acrylate (A) exceeds 70 parts by mass, the hardness of the obtained hard coat layer is low. There is a bug.

(B) Aromatic group-containing mono- or poly (meth) acrylate compound having 1 to 2 mol of an alkylene oxide structure having 2 or 3 carbon atoms in the molecule. The hard coating composition of the present invention comprises (B) 2 or 3 carbon atoms. And an aromatic group-containing mono- or poly (meth) acrylate having 1 to 2 mol of an alkylene oxide structure in the molecule. This (meth) acrylate (B) preferably has a viscosity of less than 300 mPa · s and a refractive index in the range of 1.56 to 1.64.

  In the component (B) (meth) acrylate, the alkylene oxide structure having 2 or 3 carbon atoms is contained in the molecule in an amount of 1 to 2 mol, whereby the viscosity of the component (B) can be designed to be less than 300 mPa · s. Become. Moreover, in the (meth) acrylate of the component (B), when the alkylene oxide structure having 2 or 3 carbon atoms is contained in the molecule in an amount of 1 to 2 mol, the extensibility of the obtained hard coat layer is improved. Here, examples of the “alkylene structure having 2 or 3 carbon atoms” include an ethylene oxide structure and a propylene oxide structure.

  The (meth) acrylate of component (B) is further characterized by having an aromatic group. When the (meth) acrylate of the component (B) has an aromatic group, a high refractive index such as a refractive index in the range of 1.56 to 1.64 is achieved.

  As the aromatic group-containing (meth) acrylate that can be preferably used as the component (B) in the present invention, for example, an alkyleneoxylated phenol (meth) having 1 to 2 mol of an alkylene oxide structure having 2 or 3 carbon atoms in the molecule. Examples include acrylate, alkyleneoxylated orthophenylphenol (meth) acrylate, alkyleneoxylated metaphenylphenol (meth) acrylate, alkyleneoxylated paraphenylphenol (meth) acrylate, and alkyleneoxylated cumylphenol (meth) acrylate. Among these, (meth) acrylate having two aromatic groups is more preferable in that it has a high refractive index.

  The refractive index of the component (B) can be measured with an Abbe refractometer by a method based on JIS K0062.

  The viscosity of component (B) is preferably less than 300 mPa · s. When the viscosity of a component (B) exceeds 300 mPa * s, there exists a problem that the curing reactivity of a composition will be inferior and the hardness of the hard-coat layer obtained will become low. The viscosity of the component (B) is more preferably in the range of 1 to 300 mPa · s, still more preferably in the range of 1 to 200 mPa · s.

  The viscosity of the component (B) can be measured with a B-type viscometer (TVB-22L manufactured by Toki Sangyo Co., Ltd.). Examples of the B-type viscometer include TVB-22L (manufactured by Toki Sangyo Co., Ltd.).

  The component (B) preferably has a weight average molecular weight in the range of 150 to 600, and more preferably in the range of 200 to 400.

  In this invention, it is on condition that a component (B) is contained 10-30 mass parts with respect to 100 mass parts of resin components contained in a hard-coating composition. When the (meth) acrylate (B) is contained in the hard coating composition in the above mass range, there is an advantage that the obtained hard coat layer has high hardness and high refractive index. When the amount of the component (B) is less than 10 parts by mass and when the amount of the component (B) exceeds 30 parts by mass, there is a problem that the hardness of the obtained hard coat layer is lowered.

(C) A fluorene skeleton-containing (meth) acrylate having two or more (meth) acrylate groups As one embodiment of the hard coating composition of the present invention, in addition to the above components (A) and (B), The aspect which further contains the fluorene frame | skeleton containing (meth) acrylate (C) which has the (meth) acrylate group beyond it is mentioned. Since the fluorene skeleton-containing (meth) acrylate (C) has a high refractive index, there is an advantage that the refractive index of the obtained hard coat layer can be set high.

  As a preferred example of the fluorene skeleton-containing (meth) acrylate (C), the following formula (II)

（II）

(II)

[In Formula (II), each R ³ is independently H or CH ₃ ;
R ⁴ is a -A-OC (O) CR = CH 2, A is _{independently, -OCH 2 CH 2 -, -} OCH 2 CH 2 CH 2 -, - OCH (CH 3) CH 2 - or -OCH ₂ CH (CH ₃₎ - and is, R is H or CH ₃ independently. ]
An acrylate monomer represented by

（II）−１
［上記式（II）−１中、各Ｒは水素原子またはメチル基を示し、ｍおよびｎは、それぞれ独立して、１〜５の整数を示す。］ A further preferred example of the fluorene skeleton-containing (meth) acrylate (C) is an acrylate monomer represented by the following formula (II) -1.

(II) -1
[In said formula (II) -1, each R shows a hydrogen atom or a methyl group, and m and n show the integer of 1-5 each independently. ]

  A commercially available product may be used as the fluorene skeleton-containing (meth) acrylate (C). Examples of the commercially available fluorene skeleton-containing (meth) acrylate (C) include the NK ester series marketed by Shin-Nakamura Chemical Co., Ltd. and the Ogsol EA series marketed by Osaka Gas Chemical Co., Ltd.

  Examples of commercially available acrylate monomers represented by the above formula (II) -1 include, for example, Ogsol EA-0200 (each R is a hydrogen atom, m + n = 2), commercially available from Osaka Gas Chemical Co., Ltd. 0500 (each R is a hydrogen atom, m + n = 5), EA-1000 (each R is a hydrogen atom, m + n = 10), EA-F5003 (each R is a hydrogen atom, low viscosity type), EA- F5503 (each R is a hydrogen atom, a low viscosity type), etc. are mentioned.

  The said component (C) is on condition that 15-40 mass parts is contained with respect to 100 mass parts of resin components contained in a hard-coating composition. When the amount of the component (C) exceeds 40 parts by mass, the hardness of the obtained hard coat layer may be lowered.

Other (meth) acrylates The hard coating composition of the present invention may contain other (meth) acrylates in addition to the components (A), (B) and (C). Examples of such (meth) acrylates include polyfunctional (meth) acrylate monomers and / or oligomer compounds. These polyfunctional (meth) acrylate monomers and / or oligomer compounds have a high hardness due to a curing reaction based on the reaction of (meth) acryloyl groups by irradiation with active energy rays after the hard coating composition is applied. There is an advantage that a hard coat layer can be obtained.

  The polyfunctional (meth) acrylate monomer and / or oligomer compound preferably has two or more (meth) acryloyl groups. By having two or more (meth) acryloyl groups, there is an advantage that a hard coat layer having high hardness can be obtained after irradiation with active energy rays.

  Specific examples of the polyfunctional (meth) acrylate monomer and / or oligomer compound include, for example, hydroxypropylated trimethylolpropane triacrylate, isocyanuric acid ethylene oxide-modified diacrylate, pentaerythritol triacrylate, dipentaerythritol pentaacrylate, and trimethylolpropane triacrylate. Examples thereof include acrylate, tris (acryloxyethyl) isocyanurate, ditrimethylolpropane tetraacrylate, pentaerythritol tetraacrylate, dipentaerythritol hexaacrylate, and oligomers thereof. These monomers or oligomers may be used alone or in combination of two or more.

  When a hard coating composition contains other (meth) acrylates, it is preferable that it is the range of 1-30 mass parts with respect to 100 mass parts of resin components contained in a hard coating composition, 1-25 More preferably, it is in the range of parts by mass.

The hard coating composition of the present invention such as a photopolymerization initiator preferably contains a photopolymerization initiator. Due to the presence of the photopolymerization initiator, the resin component is favorably polymerized by irradiation with active energy rays such as ultraviolet rays. Examples of photopolymerization initiators include alkylphenone photopolymerization initiators, acylphosphine oxide photopolymerization initiators, titanocene photopolymerization initiators, and oxime ester polymerization initiators. Examples of alkylphenone photopolymerization initiators include 2,2-dimethoxy-1,2-diphenylethane-1-one, 1-hydroxy-cyclohexyl-phenyl-ketone, and 2-hydroxy-2-methyl-1-phenyl-propane. -1-one, 1- [4- (2-hydroxyethoxy) -phenyl] -2-hydroxy-2-methyl-1-propan-1-one, 2-hydroxy-1- {4- [4- (2 -Hydroxy-2-methyl-propionyl) -benzyl] phenyl} -2-methyl-propan-1-one, 2-methyl-1- (4-methylthiophenyl) -2-morpholinopropan-1-one, 2- Benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone-1,2- (dimethylamino) -2-[(4-methylphenyl) methyl 1- [4- (4-morpholinyl) phenyl] -1-butanone and the like. Examples of the acylphosphine oxide photopolymerization initiator include 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide, bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide, and the like. Examples of titanocene-based photopolymerization initiators include bis (η5-2,4-cyclopentadien-1-yl) -bis (2,6-difluoro-3- (1H-pyrrol-1-yl) -phenyl) titanium. Is mentioned. Examples of the oxime ester polymerization initiator include 1.2-octanedione, 1- [4- (phenylthio)-, 2- (O-benzoyloxime)], ethanone, 1- [9-ethyl-6- (2 -Methylbenzoyl) -9H-carbazol-3-yl]-, 1- (0-acetyloxime), oxyphenylacetic acid, 2- [2-oxo-2-phenylacetoxyethoxy] ethyl ester, 2- (2-hydroxy And ethoxy) ethyl ester. These photoinitiators may be used individually by 1 type, and may use 2 or more types together.

  Among the photopolymerization initiators, 2-hydroxy-2-methyl-1-phenyl-propan-1-one, 1-hydroxy-cyclohexyl-phenyl-ketone, 2-methyl-1- (4-methylthiophenyl) -2 -Morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone-1, 2,2-dimethoxy-1,2-diphenylethane-1-one and the like More preferably used.

  The preferred amount of the photopolymerization initiator is 0 with respect to 100 parts by mass of the above components (A), (B), (C) and other (meth) acrylates (collectively referred to as “resin component”). It is 0.01-20 mass parts, More preferably, it is 1-10 mass parts.

  The hard coating composition used in the present invention may contain a solvent. The solvent is not particularly limited, and can be appropriately selected in consideration of the components contained in the composition, the type of base material to be coated, the coating method of the composition, and the like. Specific examples of the solvent that can be used include aromatic solvents such as toluene and xylene; ketone solvents such as methyl ethyl ketone, acetone, methyl isobutyl ketone, and cyclohexanone; diethyl ether, isopropyl ether, tetrahydrofuran, dioxane, and ethylene glycol. Ether solvents such as dimethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, propylene glycol monomethyl ether, anisole, and phenetol; ester solvents such as ethyl acetate, butyl acetate, isopropyl acetate, and ethylene glycol diacetate; dimethylformamide, Amide solvents such as diethylformamide and N-methylpyrrolidone; methyl Cellosolve, ethyl cellosolve, cellosolve solvents such as butyl cellosolve; methanol, ethanol, alcohol solvents such as propanol; and the like; dichloromethane, halogenated solvents such as chloroform. These solvents may be used alone or in combination of two or more. Of these solvents, ester solvents, ether solvents, alcohol solvents and ketone solvents are preferably used.

  Various additives can be added to the hard coating composition of the present invention as necessary. Examples of such additives include conventional additives such as antistatic agents, plasticizers, surfactants, and antioxidants.

The hard coating composition of the present invention does not include a high refractive index agent composed of a metal oxide such as ZnO, TiO ₂ , CeO ₂ , SnO ₂ , ZrO _2, or indium-tin oxide due to the above configuration. It is characterized in that a hard coat layer having a high refractive index can be formed. Therefore, the hard coating composition of the present invention does not contain a high refractive index agent such as a metal oxide selected from the group consisting of ZnO, TiO ₂ , CeO ₂ , SnO ₂ , ZrO ₂ and indium-tin oxide. Is preferred. More specifically, the hard coating composition preferably has a total content of ZnO, TiO ₂ , CeO ₂ , SnO ₂ , ZrO ₂ and indium-tin oxide of 0.0001% by mass or less in the composition. . This is because when a high refractive index agent such as a metal oxide is present in the hard coat layer, the stretchability and the bending resistance are generally inferior as compared with the layer containing only the resin component.

Hard Coat Film The present invention further provides a hard coat film formed using the above hard coating composition. This hard coat film has a transparent polymer base material and a hard coat layer formed by coating the base material with the hard coating composition. The hard coat layer in the present invention has a high refractive index of 1.565 to 1.620.

  In the hard coat film of the present invention, a PET film or a polycarbonate film is preferably used as the transparent polymer substrate. This is because the PET film and the polycarbonate film are suitably used as a base film for a film having a transparent conductive layer constituting a touch panel from the viewpoints of high film strength and transparency and low cost. On the other hand, these films generally have a high refractive index of 1.5 or more. Since the refractive index of these films is higher than the refractive index of the resin component constituting the normally used hard coat film, the difference in refractive index with the hard coat layer increases, and the frequency of occurrence of interference fringes increases. There's a problem.

  Here, the interference fringes refer to iris-like reflection generated by interference of light reflected at each interface in a multilayer body composed of a transparent film and a transparent coat layer. This interference fringe tends to appear prominently under irradiation of a three-wavelength fluorescent lamp. The three-wavelength light-emitting fluorescent lamp is a fluorescent lamp characterized by a strong emission intensity at a specific wavelength, which is characterized by the fact that things can be clearly seen.

  The hard coating composition of the present invention is characterized in that a hard coat layer having a high refractive index can be formed. Therefore, even if a transparent hard coat layer is formed on a transparent substrate film such as a PET film or a polycarbonate film, there is a feature that no interference fringes are generated.

  In addition, you may apply the hard-coating composition of this invention to base film other than the said PET film or a polycarbonate film. Examples of such a base film include triacetyl cellulose (TAC) film, diacetylene cellulose film, acetate butyrate cellulose film, polyether sulfone film, polyacrylic resin film, polyurethane resin film, polyester film, and polysulfone. Examples thereof include a film, a polyether film, a polymethylpentene film, a polyether ketone film, and a (meth) acrylonitrile film.

  The thickness of the transparent polymer substrate can be appropriately selected according to the use, but is generally about 20 to 300 μm.

  A hard-coat layer is formed by apply | coating said hard-coating composition on a transparent polymer base material. The coating method of the hard coating composition can be selected as appropriate according to the situation of the hard coating composition and the painting process. For example, dip coating method, air knife coating method, curtain coating method, roller coating method, wire bar coating method It can be applied by a gravure coating method or an extrusion coating method (US Pat. No. 2,681,294).

  The thickness of the hard coat layer is not particularly limited, and can be set as appropriate in consideration of various factors. For example, the hard coating composition can be applied so that a hard coat layer of 0.01 to 20 μm is obtained.

A hard coat layer is formed by curing the coating film obtained by applying the coating composition. This curing can be performed by irradiation using a light source that emits an active energy ray having a wavelength as required. As the active energy ray to be irradiated, for example, light having an exposure amount of 0.1 to 1.5 J / cm ² , preferably 0.3 to 1.5 J / cm ² can be used. The wavelength of the irradiation light is not particularly limited, and for example, irradiation light having a wavelength of 360 nm or less can be used. Such light can be obtained using a high-pressure mercury lamp, an ultra-high pressure mercury lamp, or the like.

  The hard coat film of the present invention is characterized in that a high refractive index of 1.565 to 1.620 of the hard coat layer is achieved without using a high refractive index agent. The refractive index of the hard coat layer can be measured according to JIS K7142 using, for example, an Abbe refractometer.

The hard coat film of the present invention preferably has a total light transmittance of 85% or more, more preferably 90% or more. Further, the hard coat film of the present invention preferably has a haze of 2% or less, more preferably 1% or less.
In the present _{invention, ZnO,} since the _{TiO 2, CeO 2, SnO 2} , be free of high refractive index such as ZrO ₂ high refractive index has been achieved, need to include such a high refractive index agent There is no. Therefore, it is possible to achieve a high total light transmittance and a low haze value as described above.

The total light transmittance (T _t (%)) is calculated by the following equation by measuring the incident light intensity (T ₀ ) with respect to the hard coat film and the total transmitted light intensity (T ₁ ) transmitted through the hard coat film. .

Ｈ：ヘイズ（曇価）（％）
Ｔ_ｄ：拡散透光率（％）
Ｔ_ｔ：全光線透過率（％） The haze is calculated from the following formula in accordance with JIS K7105.

H: Haze (cloudiness value) (%)
T _d : Diffuse transmittance (%)
T _t : Total light transmittance (%)

  The total light transmittance and the haze value can be measured using, for example, a haze meter (manufactured by Suga Test Instruments Co., Ltd.).

  In addition to having high hardness and refractive index, the hard coat layer formed using the hard coating composition of the present invention is also characterized by having high extensibility. Therefore, the hard coat film in this invention can be used suitably in preparation of the film which has a transparent conductive layer which comprises a touchscreen etc., for example.

  In mobile phones such as smartphones equipped with touch panels, tablet PCs, and portable information terminal devices, there is a strong demand for smaller, thinner, and lighter devices. Therefore, thinning of the base film is also required for members constituting the touch panel electrode. On the other hand, by reducing the thickness of the base film, when the hard coat layer is provided on the base film, the frequency of occurrence of defects that cause warping or curling of the film increases, and workability and productivity decrease. There is a problem. These defects are considered to depend on the difference in physical properties (for example, thermal shrinkage rate, thermal expansion rate, etc.) between the hard coat layer and the base film. Since the hard coat film in the present invention has high extensibility, the curl tends to be small with respect to various substrates.

  In the hard coat film according to the present invention, a transparent conductive layer and an optical interference layer for controlling the reflectance by optical interference can be used in combination in an appropriate order as required. The order in which the transparent conductive layer, the optical interference layer, and the hard coat layer are laminated is not particularly limited as long as the function expected to be exhibited is achieved according to the application. For example, when these layers are used as a touch panel substrate, the transparent conductive layer is A, the optical interference layer is B, the hard coat layer that is the subject of the present invention is C, the transparent polymer substrate is D, and the subject is not subject to the present invention. For example, A / B / C / D / E, A / B / C / D / C, A / B / B / C / D / E, A / B / B / C / D / C, A / C / D / E / B, A / C / D / C / B, A / C / D / E / B / B, A / C / D / C / B / B, etc. can do.

  The optical interference layer described above refers to a layer that prevents or suppresses reflected light by appropriately combining a high refractive index layer and a low refractive index layer. The optical interference layer is composed of at least one high refractive index layer and at least one low refractive index layer. Two or more combination units of the high refractive index layer and the low refractive index layer may be used. When the optical interference layer is composed of one high refractive index layer and one low refractive index layer, the thickness of the optical interference layer is preferably 30 nm to 150 nm, and more preferably 50 nm to 150 nm. The optical interference layer can be formed by either a wet method or a dry method. For example, in the wet method, doctor knife, bar coater, gravure roll coater, curtain coater, knife coater, spin coater, etc., spray method, dipping method, etc., in dry method, PVD method such as sputtering method, vacuum deposition method, ion plating method, etc. Printing method, CVD method, etc. can be applied.

  A transparent conductive laminate constituting a touch panel or the like is generally a film having a transparent conductive layer. The transparent conductive layer is not particularly limited, but a crystalline layer containing indium oxide, more specifically, indium such as ITO (indium-tin oxide) and IZO (indium-zinc oxide) as a main component. A crystalline layer is preferably used. As a method for forming the transparent conductive layer, there are a PVD method such as a sputtering method, a vacuum deposition method, and an ion plating method, a coating method, a printing method, and a CVD method, and the PVD method or the CVD method is preferable.

  By carrying out these processing steps for providing the transparent conductive layer, a partial load is applied to the base film having the hard coat layer, so that the transparent conductive layer of the transparent conductive laminate, the hard coat layer and the base film The film may be twisted based on the difference in thermal shrinkage and thermal expansion between the two. The hard coat layer provided using the hard coating composition of the present invention is characterized by having high visibility and good hardness and high extensibility. Due to the high extensibility of the obtained hard coat layer, even when the base film is locally thermally expanded by heating in the stage of providing the transparent conductive layer, the hard coat layer follows well, As a result, there is an advantage that defects such as film warp do not occur.

  More specifically, regarding the extensibility of the hard coat layer, in the case where the transparent polymer substrate on which the hard coating composition is applied is a hard coat film having a thickness of 20 to 300 μm, this hard coat film When the film is stretched by 15% in the MD direction at 20 ° C. under the condition of a pulling speed of 5 mm / sec, there is a state in which no crack is generated in the hard coat layer. Here, the case where it is 0.05-10 micrometers as a film thickness of a hard-coat layer is mentioned, for example.

  In general, the production of a polymer base film is performed by winding a resin base material in a molten state in a roll shape while being perpendicular to the vertical direction (winding direction: MD direction) and the horizontal direction (TD direction: MD direction). The film is produced by a biaxial stretching method in which a film having a uniform thickness is produced. In this manufacturing method, high stress remains in the MD direction. Therefore, the obtained film tends to cause thermal expansion / shrinkage particularly in the MD direction. Generation of cracks (film cracks) and the like can be effectively verified by performing a test in which the obtained hard coat film is stretched in the MD direction, which is the direction wound during the production of the polymer base film. There is an advantage.

  Further, when the transparent polymer substrate constituting the hard coat film is a polycarbonate film, the elongation performance of the formed hard coat layer can be evaluated by verifying the bending resistance of the hard coat film. . Polycarbonate is a material with excellent physical properties such as heat resistance and impact resistance, but especially in the case of a polycarbonate film with a thin film thickness, cracks may occur due to stress such as bending. . When a polycarbonate film having a thin film thickness is used as a base film, when the hard coat layer formed on the base film has high extensibility, by providing the hard coat layer, It becomes possible to prevent the occurrence of cracks. The hard coat layer formed by the hard coating composition of the present invention has high extensibility. Therefore, in the hard coat film using a polycarbonate having a thin film thickness as a base film, there is an advantage that toughness against bending stress can be improved. More specifically, in the case where the transparent polymer substrate to which the hard coating composition is applied is a hard coat film which is a polycarbonate film having a thickness of 30 to 200 μm, the hard coat film is treated at 25 ° C. and 60 degrees / degree. Even when it is bent 180 ° under the second condition, there is a state in which no crack occurs in either the hard coat layer or the substrate. Here, the case where it is 0.05-10 micrometers as a film thickness of a hard-coat layer is mentioned, for example.

  The hard coat layer formed using the hard coating composition of the present invention is characterized by having good hardness and high visibility and extensibility. The transparent hard coat layer formed by the hard coating composition of the present invention has a high refractive index. Therefore, even when the transparent hard coat layer in the present invention is provided on a base film having a high refractive index such as a PET film or a polycarbonate film, there is an advantage that no interference fringes are generated. In particular, the hard coat layer in the present invention can be suitably used in a film having a transparent conductive layer constituting a touch panel electrode.

  The following examples further illustrate the present invention, but the present invention is not limited thereto. In the examples, “parts” and “%” are based on mass unless otherwise specified.

Production Example 1 Production of phenol novolac acrylate (1) In a reactor equipped with a stirrer, a thermometer, a dropping funnel and a reflux device, 150 g of phenol novolac resin (weight average molecular weight 700 to 900, epoxy equivalent 150 to 200) and epichlorohydrin were prepared. 550g was mixed and 110g of 48.5% sodium hydroxide aqueous solution was dripped over 2 hours under 100 degreeC and 100-200 mg pressure reduction conditions. After completion of the reaction, the temperature is cooled to room temperature, an excess aqueous sodium hydroxide solution is neutralized with an acid, heated under reduced pressure to remove excess epichlorohydrin, the product is dissolved in methyl isobutyl ketone, washed with water and filtered. By-product salts were removed to obtain a phenol novolac type epoxy resin solution.
Metoquinone 1000 ppm and triphenylphosphine 2000 ppm are added to 100 parts by weight of the solid content of the obtained phenol novolac type epoxy resin, and acrylic acid is added dropwise at 100 ° C. until the acid value becomes 1 mgKOH / g or less. A phenol novolac type epoxy acrylate (1) was obtained.
The obtained phenol novolak epoxy acrylate (1) had a weight average molecular weight of 950, a hydroxyl value of 140 mgKOH / g, and a refractive index of 1.572.

Production Example 2 Production of Phenol Novolac Type Acrylate (2) In a reaction apparatus equipped with a stirrer, thermometer, dropping funnel and reflux apparatus, 150 g of phenol novolac resin (weight average molecular weight 900-1100, epoxy equivalent 150-200) and epichlorohydrin 550g was mixed and 110g of 48.5% sodium hydroxide aqueous solution was dripped over 2 hours under 100 degreeC and 100-200 mg pressure reduction conditions. After completion of the reaction, the temperature is cooled to room temperature, an excess aqueous sodium hydroxide solution is neutralized with an acid, heated under reduced pressure to remove excess epichlorohydrin, the product is dissolved in methyl isobutyl ketone, washed with water and filtered. By-product salts were removed to obtain a phenol novolac type epoxy resin solution.
Metoquinone 1000 ppm and triphenylphosphine 2000 ppm are added to 100 parts by weight of the solid content of the obtained phenol novolac type epoxy resin, and acrylic acid is added dropwise at 100 ° C. until the acid value becomes 1 mgKOH / g or less. A phenol novolac epoxy acrylate (2) was obtained.
The obtained phenol novolak type epoxy acrylate (2) had a weight average molecular weight of 1200, a hydroxyl value of 137 mgKOH / g, and a refractive index of 1.571.

Example 1
As the component (A), the phenol novolac type epoxy acrylate (1) obtained in Production Example 1 is used, and as the component (B), ethoxylated orthophenylphenol acrylate (acrylate having 1 mol of ethoxy structure in the molecule, viscosity at 25 ° C. 130 mPa · s, refractive index 1.577) as component (C), ogsol EA-0200 (in the formula (II) -1 below, each R is a hydrogen atom and m + n = 2), (Osaka Gas Chemical Co., Ltd.)

（II）−１

(II) -1

Was used to prepare a hard coating composition. The raw materials shown in Table 1 were sequentially mixed at the solid content mass shown in Table 1 and stirred to obtain a hard coating composition.
In addition, the viscosity measurement of the ethoxylated orthophenylphenol acrylate of the component (B) was obtained by collecting 100 ml of the ethoxylated orthophenylphenol acrylate of the component (B) as a test sample in a glass container and adjusting the temperature to 20 ° C. Using a viscometer (TVB-22L manufactured by Toki Sangyo Co., Ltd.) and M1Rotor, the measurement was performed at a rotation speed of 60 rpm.
The refractive index of component (B) was measured using an Abbe refractometer by a method based on JIS K0062.

The obtained hard coating composition was dropped onto a Teijin DuPont 188 μm optical PET film (KEFW) and coated using a bar coater # 12.
After coating, the film was dried at 70 ° C. for 1 minute, and irradiated with 350 mJ of ultraviolet light using an ultraviolet irradiator (manufactured by Fusion) to obtain a PET film and a hard coat film having a 6.5 μm thick hard coat layer.

The obtained hard coating composition was dropped onto a Teijin Chemicals 100 μm optical PC film (Pure Ace) and coated using a bar coater # 9.
After coating, it was dried at 70 ° C. for 1 minute, and irradiated with 350 mJ of ultraviolet rays with an ultraviolet irradiator (manufactured by Fusion) to obtain a hard coat film having a polycarbonate film and a hard coat layer having a thickness of 5.0 μm.

Examples 2-4
The hard coating composition was changed in the same manner as in Example 1 except that the type and amount of component (A) were changed to those shown in Table 1 and pentaerythritol triacrylate was used as the other (meth) acrylates. A product was prepared. Using the obtained hard coating composition, two types of hard coat films were obtained in the same manner as in Example 1.
In Example 4, Ogsol EA-F5503 (manufactured by Osaka Gas Chemical Co., Ltd.) was used as the component (C).

Comparative Examples 1-5, 9
With the formulation shown in Table 2, hard coating compositions were prepared as in the examples. Using the obtained hard coating composition, two types of hard coat films were obtained in the same manner as in Example 1.

Comparative Examples 6 and 10
With the formulation shown in Table 2, hard coating compositions were prepared as in the examples.
The obtained hard coating composition was dropped onto a Teijin DuPont 188 μm optical PET film (KEFW) and coated using a bar coater # 13. After coating, the film was dried at 70 ° C. for 1 minute, and irradiated with 350 mJ of ultraviolet light using an ultraviolet irradiator (manufactured by Fusion) to obtain a PET film and a hard coat film having a 6.5 μm thick hard coat layer.
Further, the obtained hard coating composition was dropped onto a 100 μm optical PC film (Pure Ace) manufactured by Teijin Chemicals and coated using a bar coater # 10. After coating, it was dried at 70 ° C. for 1 minute, and irradiated with 350 mJ of ultraviolet rays with an ultraviolet irradiator (manufactured by Fusion) to obtain a hard coat film having a polycarbonate film and a hard coat layer having a thickness of 5.0 μm.

Comparative Examples 7 and 11
With the formulation shown in Table 2, hard coating compositions were prepared as in the examples.
The obtained hard coating composition was dropped onto a Teijin DuPont 188 μm optical PET film (KEFW) and coated using a bar coater # 16. After coating, the film was dried at 70 ° C. for 1 minute, and irradiated with 350 mJ of ultraviolet light using an ultraviolet irradiator (manufactured by Fusion) to obtain a PET film and a hard coat film having a 6.5 μm thick hard coat layer.
Further, the obtained hard coating composition was dropped onto a 100 μm optical PC film (Pure Ace) manufactured by Teijin Chemicals and coated using a bar coater # 12. After coating, it was dried at 70 ° C. for 1 minute, and irradiated with 350 mJ of ultraviolet rays with an ultraviolet irradiator (manufactured by Fusion) to obtain a hard coat film having a polycarbonate film and a hard coat layer having a thickness of 5.0 μm.

Comparative Examples 8, 12, 13
With the formulation shown in Table 2, hard coating compositions were prepared as in the examples.
The obtained hard coating composition was dropped onto a Teijin DuPont 188 μm optical PET film (KEFW) and coated using a bar coater # 20. After coating, the film was dried at 70 ° C. for 1 minute, and irradiated with 350 mJ ultraviolet rays with an ultraviolet irradiation machine (manufactured by Fusion). When the hard coating composition of Comparative Example 12 was used, a hard coat film having a PET film and a hard coat layer with a film thickness of 6.5 μm was obtained. On the other hand, in the case where the hard coating compositions of Comparative Examples 8 and 13 were used, the coating composition was not cured and a hard coat layer could not be provided.
Further, the obtained hard coating composition was dropped onto a 100 μm optical PC film (Pure Ace) manufactured by Teijin Chemicals and coated using a bar coater # 14. After coating, the film was dried at 70 ° C. for 1 minute, and irradiated with 350 mJ ultraviolet rays with an ultraviolet irradiation machine (manufactured by Fusion). When the hard coating composition of Comparative Example 12 was used, a hard coat film having a polycarbonate film and a hard coat layer having a thickness of 5.0 μm was obtained. On the other hand, in the case where the hard coating compositions of Comparative Examples 8 and 13 were used, the coating composition was not cured and a hard coat layer could not be provided.

Example 5
Sputtering method using the hard coat film obtained in Example 1 and further using an indium oxide-tin oxide target having a composition of indium oxide and tin oxide in a weight ratio of 95: 5 and a packing density of 98% on the cured resin layer. Thus, an ITO layer was formed, and a transparent conductive laminate to be a movable electrode substrate was produced. The thickness of the formed ITO layer was about 30 nm, and the surface resistance value after film formation was about 150Ω / □. The interference fringes of the obtained transparent conductive laminate were not visually recognized.

  The following evaluation was performed about the hard coat film obtained in the said Examples 1-4 and Comparative Examples 1-13. The evaluation results are shown in Tables 1 and 2.

Measurement of refractive index The refractive index was measured by the following method using an Abbe refractometer (2T measurement range nD = 1.3 to 1.7 manufactured by Atago Co., Ltd.).
On the main prism, a drop of an intermediate solution (monobromonaphthalene, etc.) was dropped with a dropper and a sample to be measured was placed. One drop of the intermediate solution was dropped on the sample with a dropper, and the secondary prism was closed. Here, the condition is that air does not enter the intermediate liquid layer.
Lamp light was incident on the sub-prism, the measurement knob was turned while looking through the eyepiece, the boundary of the light and darkness of the refractive field was adjusted to the intersection, the value of the scale field was read to 4 digits after the decimal point, and the refractive index was measured.

Evaluation of Hardness The hardness was measured using a pencil scratch coating film hardness tester (model P, pressure load 100 g to 1 kg, manufactured by Toyo Seiki Seisakusho).
A pencil for pencil scratch test (manufactured by the Japan Paint Inspection Association) manufactured by Mitsubishi Uni was used, and the tip of the lead was adjusted with abrasive paper (3MP-1000) so that it had a smooth and circular cross section. After placing the sample on the measuring table, the pencil was fixed so that the scratch angle was 45 °, and the test was performed under the condition of a load of 750 g. For each test, the test was repeated five times while shifting the test location while smoothing the core.
The presence or absence of dents on the surface of the coating film was confirmed visually based on the following evaluation criteria.
For example, in the case of a test using a 2H pencil,
When no dent was generated, it was determined as 2H.
When the occurrence of dents is 1 to 2, the pencil hardness is evaluated by one step down, and when there is no dent after one step, the hardness is evaluated as an intermediate region (H to 2H, etc.). did.
When the number of dents was 3 or more, it was judged as H or less, and the evaluation was performed in the same manner with one step lowered.

In addition, the hardness of the PET film used in preparation of the hard coat film of an Example and a comparative example is HB-F, and the hardness of a polycarbonate (PC) film is 5B-4B.
Therefore, in a hard coat film having a PET film and a hard coat layer, if the hardness is H or more, the hardness is increased by two or more stages, and it is determined that the hard coat layer has sufficient hardness. .
Further, in a hard coat film having a polycarbonate film and a hard coat layer, if the hardness is 3B or more, the hardness is increased by two or more steps, and it is determined that the hard coat layer has sufficient hardness. .

The elongation was measured using an autograph (AG-1S manufactured by Shimadzu Corporation).
A test sample is cut out to 10 mm × 150 mm, and is sandwiched between upper and lower chucks of the measuring instrument in a direction in which the longitudinal direction of the sample is extended. When a sample sample was stretched at a speed of 2 cm / sec under room temperature (20 ° C.) conditions, an elongation rate at which no breakage / crack occurred was obtained.

Bending resistance test method The sample was adjusted to 50 mm x 50 mm, and the sample was evaluated by bending it 180 °. Based on the following evaluation criteria, it performed visually.
○: Cracks do not occur in the coating film / base material.
Δ: Cracks can be confirmed only in the coating film.
X: The occurrence of cracks can be confirmed in both the coating film and the substrate.

Interference fringe evaluation method
Interference fringes (appearance evaluation)
The test piece was bonded to a 100 × 100 mm black acrylic plate using an optical film adhesive so that the coated surface was on the surface. A sample is placed at a distance of 10 cm vertically from the fluorescent tube of a stand-type three-wavelength fluorescent lamp (SLH-399, manufactured by TWINBARD) and visually observed. Visual observation was performed and judged based on the following evaluation criteria.
A: Interference fringes (interference patterns) are not visually recognized under a three-wavelength fluorescent lamp or in sunlight.
○: Interference fringes (interference patterns) are not visually recognized under a three-wavelength fluorescent lamp, but slightly visible under sunlight Δ: Interference fringes (interference patterns) are slightly visible ×: Interference fringes (interference patterns) Clearly visible

Interference fringes (transmission spectrum amplitude)
The light transmittance of the test piece was measured with an ultraviolet-visible spectrophotometer (UV-2450, manufactured by Shimadzu Corporation)
The determination was made based on the following evaluation criteria for the amplitude of the transmittance in the range of 500 to 750 nm.
○: The difference between the maximum value and the minimum value of the transmittance is less than 0.5% △: The difference between the maximum value and the minimum value of the transmittance is 0.5% or more and less than 1.0% ×: The maximum value and the minimum value of the transmittance Difference in value is 1.0% or more

In Table 1 and Table 2 above,
I-184: 1-hydroxycyclohexyl phenyl ketone, photopolymerization initiator bisphenol A EO modified diacrylate: manufactured by Toa Gosei Co., Ltd., Aronix M-211B, bisphenol A EO (2 mol) modified diacrylate high refractive index filler 1: zirconia ZRMIBK30WT % (Zirconium oxide, manufactured by CIK Nanotech)
High refractive index filler 2: Titania TiMIBK15WT% (titanium oxide, manufactured by CIK Nanotech)
Bifunctional urethane acrylate: NV100: CN-9893 (manufactured by Sartomer)
Indicates.

All of the hard coating films having a hard coating layer formed using the hard coating composition of the example had no generation of interference fringes and had a high refractive index and good hardness. Furthermore, the obtained hard coating film had high extensibility and bending resistance.
Comparative Example 1 is an example in which the amount of component (A) and component (C) is less than the range in the present invention. In Comparative Example 1, the film extensibility and flex resistance were inferior.
Comparative Example 2 is an example in which the amount of component (A) is less than the range in the present invention and the amount of component (C) exceeds the range in the present invention. In Comparative Example 2, there was a problem that the hardness of the obtained film was lowered.
Comparative Example 3 is an example in which diacrylate having a bisphenol A skeleton was used instead of component (A). In Comparative Example 3, the refractive index of the obtained film was lowered, and the occurrence of interference fringes was confirmed. There was also a problem that the hardness was lowered.
Comparative Example 4 is an example using acryloylmorpholine instead of component (B). Also in Comparative Example 4, the refractive index of the obtained film was lowered, and the occurrence of interference fringes was confirmed. Moreover, the extensibility was also inferior.
Comparative Examples 5 to 8 are examples using zirconia oxide or titanium oxide, which is a high refractive index agent, instead of using the components (A) and (B). In these comparative examples, while the hardness was good, the extensibility was greatly inferior. Note that the composition of Comparative Example 8 did not cure.
Comparative Examples 9 to 13 are examples using a bifunctional urethane acrylate for the purpose of imparting extensibility to the hard coat layer. In these comparative examples, although there was an example in which the extensibility was somewhat improved, the balance between hardness and refractive index was poor. Note that the composition of Comparative Example 13 did not cure.

The hard coating compositions of Comparative Examples 5 to 13 contain a high refractive index filler. By including the high refractive index filler, the refractive index itself of the obtained hard coat layer is certainly high. On the other hand, interference fringes are confirmed in any of the hard coat layers obtained in these comparative examples. The reason why the interference fringes were confirmed in these comparative examples is that the resin component forming the hard coat layer has a low refractive index, while a high refractive index filler having a high refractive index is mixed in the resin component. This is probably because of this. For this reason, even if the refractive index itself of the hard coat layer is increased, the resin component having a low refractive index has an adverse effect, and it is considered that an excellent interference fringe generation suppressing effect cannot be obtained.
Also, from the results of these examples and comparative examples, it can be seen that an excellent interference fringe suppressing effect is achieved in the hard coat layer obtained by the present invention.

  1 is a graph showing a transmission spectrum (transmittance (%)) in a wavelength range of 400 to 800 nm of a hard coat layer obtained by using the hard coating composition of Example 1. FIG. FIG. 2 is a graph showing a transmission spectrum (transmittance (%)) in the wavelength range of 400 to 800 nm of the hard coat layer obtained using the hard coating composition of Comparative Example 10. As shown in these transmission spectra of FIGS. 1 and 2, the hard coat layer obtained using the hard coating composition of the present invention has a very small amplitude width in the transmission spectrum and optical blurring in the visible wavelength range. Can be understood. On the other hand, it can be understood that the hard coat layer obtained using the hard coating composition of Comparative Example 10 has a large amplitude width in the transmission spectrum and a large optical blur in the visible wavelength range. Also from these transmission spectrum results, the technical effect of the present invention can be understood for confirmation.

  The transparent hard coat layer formed by the hard coating composition of the present invention is characterized by having good hardness and high visibility and extensibility. The transparent hard coat layer formed by the hard coating composition of the present invention has a high refractive index. Therefore, even when the transparent hard coat layer in the present invention is provided on a base film having a high refractive index such as a PET film or a polycarbonate film, interference fringes are not generated and high extensibility is achieved. There is an advantage that.

Claims (13)

(A) a phenol novolac acrylate having 2 or more acrylate groups,
(B) An aromatic group-containing mono- or poly (meth) acrylate having 1 to 2 mol of an alkylene oxide structure having 2 or 3 carbon atoms in the molecule, and (C) 2 or more (meth) acrylate groups Fluorene skeleton-containing (meth) acrylate,
A hard coating composition comprising:
The phenol novolac acrylate (A) is 40 to 70 parts by mass, the (meth) acrylate (B) is 10 to 30 parts by mass and the fluorene skeleton is contained (meta) with respect to 100 parts by mass of the resin component contained in the hard coating composition. ) Acrylate (C) is contained in 15-40 parts by mass,
Hard coating composition. The phenol novolac acrylate (A) has the following formula (I)

(I)
[In Formula (I), R ¹ is H or CH ₂ OH, R ² is H or OH, n is 2 to 5, and m is 0 to 5. ]
The hard coating composition of claim 1, wherein   The hard coating composition according to claim 1 or 2, wherein the (meth) acrylate (B) is an aromatic group-containing (meth) acrylate having a refractive index in the range of 1.56 to 1.64. The fluorene skeleton-containing (meth) acrylate (C) has the following formula (II)

(II)
[In Formula (II), each R ³ is independently H or CH ₃ ;
R ⁴ is a -A-OC (O) CR = CH 2, A is _{independently, -OCH 2 CH 2 -, -} OCH 2 CH 2 CH 2 -, - OCH (CH 3) CH 2 - or -OCH ₂ CH (CH ₃₎ - and is, R is H or CH ₃ independently. ]
The hard-coating composition in any one of Claims 1-3 shown by these. The hard coating composition according to claim 1, wherein the total content of ZnO, TiO ₂ , CeO ₂ , SnO ₂ , ZrO ₂ and indium-tin oxide is 0.0001% by mass or less in the composition. object. A transparent polymer substrate, and
A hard coat layer formed by applying the hard coating composition according to claim 1 to a substrate,
A hard coat film having
The hard coat layer has a refractive index of 1.565 to 1.620,
Hard coat film.   The hard coat film according to claim 6, wherein the hard coat layer has a thickness of 0.05 to 10 μm. The base material is a PET film having a thickness of 20 to 300 μm,
The hard coat film is characterized in that cracks do not occur in the hard coat layer when the film is stretched 15% in the MD direction at 20 ° C. under a pulling speed of 5 mm / second.
The hard coat film according to claim 6 or 7. The base material is a polycarbonate film having a thickness of 30 to 200 μm,
The hard coat film is characterized in that cracks do not occur in either the hard coat layer or the substrate when bent at 180 ° under the conditions of 25 ° C. and 60 degrees / second,
The hard coat film according to claim 6 or 7.   The transparent conductive laminated body in which the transparent conductive layer was formed on the at least one surface of the hard coat film in any one of Claims 6-9.   The transparent conductive laminate according to claim 10, wherein the transparent conductive layer is a crystalline layer containing indium oxide, and the thickness of the transparent conductive layer is 5 to 50 nm.   The transparent conductive laminate according to claim 10 or 11, wherein a metal oxide layer is present between the hard coat layer and the transparent conductive layer, and the thickness of the metal oxide layer is 0.5 to 5.0 nm.   A touch panel having the transparent conductive laminate according to claim 10.

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