JP2003251751A - Hard coat film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hard coat film capable of enhancing representative ability and visual perception without reducing hard coat performance and causing no deterioration in haze values nor in total light transmittance. <P>SOLUTION: The hard coat film having a hard coat layer (a) on one face of a base film is formed by laminating ionizing radiation-curable resin layers (b) and (c) an ionizing radiation-curable resin layer in sequence on the other face thereof. The hard coat layer (a) is 2-20 μm in thickness. The ionizing radiation-curable resin layer (b) has a refractive index in a range of 1.47-1.56 with 2-20 μm in thickness. The ionizing radiation-curable resin layer (c) contains metal oxides and has a refractive index in a range of 1.65-1.72 with 40-250 nm in thickness. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a hard coat film. More specifically, the present invention is used for a resistive film type touch panel, and by providing a refractive index adjusting layer, a touch panel hard disk having improved image displayability and visibility without deteriorating the hard coat performance. It relates to a coated film.

[0002]

2. Description of the Related Art In recent years, a touch panel has been used as an input device for a portable information terminal whose market has been increasing. This touch panel directly touches the display screen with your finger,
A device that inputs data by touching it with a pen or the like. About 90% of the touch panels currently employ a resistive film type. The touch panel of the resistance film type generally has a touch-side plastic substrate in which a transparent conductive thin film such as a tin-doped indium oxide (ITO) film is laminated on one surface of a transparent plastic substrate, and an I-shaped one side of a transparent substrate such as glass.
It has a structure in which a display-side transparent substrate having a transparent conductive thin film such as a TO film laminated thereon is opposed to each other so that the transparent conductive thin films face each other via an insulating spacer.
For input, the touch input surface of the touch-side plastic substrate (the surface opposite to the transparent conductive thin film side; hereinafter the same) is pressed with a pen or finger, and the touch-side plastic substrate is connected with the transparent conductive thin film. , The transparent conductive thin film on the display-side transparent substrate is brought into contact with the transparent substrate. However, in such a resistive film type touch panel, by repeating the input operation, that is, by repeating the contact between the transparent conductive thin film of the touch side plastic substrate and the transparent conductive thin film of the display side transparent substrate, the touch side plastic substrate There arise problems such as abrasion of the transparent conductive thin film of the substrate, generation of cracks, and separation from the base material. Therefore, in order to solve such problems,
Generally, a hard coat layer made of a synthetic resin is provided between a transparent plastic substrate and a transparent conductive thin film. However, since the refractive index of an ITO film, which is a typical transparent conductive thin film, is about 2, the refractive index of a hard coat layer made of synthetic resin is about 1.4 to 1.6. Due to the film, light on the short wavelength side is reflected, and a phenomenon occurs that the touch-side plastic substrate becomes yellowish. As a result, the visibility of the display image is reduced, and in the case of a touch panel for color display, the original color is slightly changed, and the displayability is reduced, which causes an undesirable situation. By the way, it is also scientifically known that the color tone is changed by providing a layer for adjusting the refractive index between the ITO film having a refractive index of about 2 and the hard coat layer. However, it has been impossible in the past to provide a refractive index adjusting layer without deteriorating the hard coat performance or impairing the optical characteristics such as haze value and total light transmittance. When the hard coat performance is lowered, in the case of a pen input type, the hard coat layer and the ITO film are easily scratched by the writing pressure, and when the haze value is increased or the total light transmittance is decreased, the visibility is decreased. I cannot escape. Therefore, attempts have been made to reduce the thickness of the ITO film, but in this case, there is a problem that sufficient conductivity cannot be obtained.

[0003]

Under the above circumstances, the present invention provides a hard coat film used as a touch-side plastic substrate in a resistive touch panel, which does not deteriorate the hard coat performance. Alternatively, the object of the present invention is to provide a hard coat film for a touch panel that can improve displayability and visibility without impairing the haze value and the total light transmittance.

[0004]

Means for Solving the Problems As a result of intensive studies to develop a hard coat film having the above-mentioned excellent function, the present inventors have found that the hard coat layer on the side of the base film on which the ITO film is to be provided is formed. It was found that the object can be achieved by providing a hard coat layer having an intermediate refractive index between the refractive index of the hard coat layer and the refractive index of the ITO film, and the present invention is based on this finding. It came to completion. That is, in the present invention, (1) a hard coat layer having a thickness of 2 to 20 μm is provided on one surface of a substrate film, and (b) a refractive index of 1.47 to 1 is provided on the other surface. .
A cured resin layer having a thickness of 2 to 20 μm in the range of 56 by ionizing radiation and (c) a metal oxide having a refractive index of 1.
A hard coat film in which a cured resin layer having a thickness of 40 to 250 nm in the range of 65 to 1.72 by ionizing radiation is laminated in order, and the metal oxide in the layer (2) and (c) is zirconium oxide and / or antimony. The hard coat film according to claim 1, which is doped tin oxide, and the hard coat film according to claim 1 or 2, which has a tin-doped indium oxide film having a thickness of 5 to 100 nm on the (3) (c) layer. , Is provided.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION The base film in the hard coat film for a touch panel of the present invention is not particularly limited and may be appropriately selected and used from known transparent plastic films conventionally used for touch panels. it can. Examples of such plastic films include polyester films such as polyethylene terephthalate, polybutylene terephthalate and polyethylene naphthalate, polyethylene films, polypropylene films, cellophane, diacetyl cellulose films, triacetyl cellulose films, acetyl cellulose butyrate films, polychlorinated films. Vinyl film, polyvinylidene chloride film, polyvinyl alcohol film, ethylene-vinyl acetate copolymer film,
Examples thereof include polystyrene film, polycarbonate film, polymethylpentene film, polysulfone film, polyetheretherketone film, polyethersulfone film, polyetherimide film, polyimide film, fluororesin film, polyamide film, acrylic resin film and the like. The thickness of the base film is not particularly limited, but is usually 20 to 300 μm, preferably 50 to 250 μm. If the thickness is less than 20 μm, the mechanical strength is insufficient, the deformation with respect to the pen input when used in a touch panel becomes too large, and the durability may be insufficient.
On the other hand, when it exceeds 300 μm, when it is used for a touch panel,
The pen load for deforming the film becomes large, which is not preferable. Further, this substrate film can be subjected to a surface treatment by a primer treatment, or an oxidation method or a textured method on one side or both sides, if desired, for the purpose of improving the adhesiveness with a layer provided on the surface thereof. . Examples of the oxidation method include corona discharge treatment, chromic acid treatment (wet), flame treatment, hot air treatment, ozone / ultraviolet irradiation treatment, and the like, and examples of the roughening method include a sandblast method and a solvent treatment method. To be These surface treatment methods are appropriately selected depending on the type of the base film,
Generally, the corona discharge treatment method is preferably used from the viewpoints of effects and operability.

In the hard coat film of the present invention, a hard coat layer is provided as a layer (a) on one surface of the base film. This hard coat layer contains
Both a thermosetting resin composition and an ionizing radiation curable resin composition can be used as the forming coating liquid. The ionizing radiation in the present invention refers to electromagnetic waves or charged particle beams having energy quantum, that is, ultraviolet rays or electron beams. The thermosetting resin composition is not particularly limited, and can be appropriately selected and used from conventionally known ones. This thermosetting resin composition generally contains a thermosetting resin as a basic component and, if desired, further contains other resins and a curing agent. The thermosetting resin generally has a molecular weight of 200.
Approximately 2,000,000 is used. Examples of the thermosetting resin include acrylate polymers having a carbon-carbon double bond or a glycidyl group, unsaturated polyesters, isoprene polymers, butadiene polymers, epoxy resins, phenol resins, urea resins, melamine resins and the like. Can be mentioned. These may be used alone or in combination of two or more. Further, as the other resin, vinyl resin, urethane resin, polyester, polyamide, polycarbonate, polyimide, nitrile resin,
Silicone resin etc. are mentioned. These resins are used for adjusting the viscosity of the coating liquid and for imparting desired physical properties to the hard coat layer, and may be used alone or in combination of two or more kinds. Examples of the curing agent include organic peroxides such as dibenzoyl peroxide, dilauroyl peroxide, t-butyl peroxybenzoate, and di-2-ethylhexyl peroxydicarbonate, 2,2'-azobisisobutyronitrile. Azo compounds such as 2,2'-azobis-2-methylbutyronitrile, 2,2'-azobisdimethylvaleronitrile, polyisocyanate compounds such as tolylene diisocyanate, diphenylmethane diisocyanate, isophorone diisocyanate and hexamethylene diisocyanate, phenylene Polyamines such as diamine, hexamethylenetetramine, isophoronediamine and diaminodiphenylmethane, acid anhydrides such as dodecenyl succinic anhydride, phthalic anhydride and tetrahydrophthalic anhydride, 2
-Methylimidazole, 2-ethylimidazole, 2-
Examples thereof include imidazoles such as phenylimidazole, dicyandiamide, Lewis acids such as p-toluenesulfonic acid and trifluoromethanesulfonic acid, and formaldehyde. These curing agents are appropriately selected according to the type of thermosetting resin used.

If desired, the thermosetting resin composition may have an improved antiglare property and flexural modulus of the hard coat layer.
For the purpose of stabilizing volume shrinkage and improving heat resistance,
For example, various fillers such as silica, alumina and hydrated alumina may be added. Further, various additives such as an antioxidant, an ultraviolet absorber, a light stabilizer, an antistatic agent, a leveling agent, an antifoaming agent and the like can be added. on the other hand,
Examples of the ionizing radiation-curable resin composition include those containing a photopolymerizable prepolymer and / or a photopolymerizable monomer and optionally a photopolymerization initiator. The photopolymerizable prepolymer includes a radical polymerization type and a cationic polymerization type, and examples of the radical polymerization type photopolymerizable prepolymer include polyester acrylate-based, epoxy acrylate-based, urethane acrylate-based, and polyol acrylate-based. To be Here, as the polyester acrylate-based prepolymer, for example, by esterifying the hydroxyl group of the polyester oligomer having a hydroxyl group at both ends obtained by condensation of a polyvalent carboxylic acid and a polyhydric alcohol with (meth) acrylic acid,
Alternatively, it can be obtained by esterifying the terminal hydroxyl group of an oligomer obtained by adding an alkylene oxide to a polycarboxylic acid with (meth) acrylic acid.
The epoxy acrylate prepolymer can be obtained, for example, by reacting (meth) acrylic acid with the oxirane ring of a bisphenol type epoxy resin or novolac type epoxy resin having a relatively low molecular weight to esterify. The urethane acrylate prepolymer is, for example,
It can be obtained by esterifying a polyurethane oligomer obtained by reacting a polyether polyol or polyester polyol with a polyisocyanate with (meth) acrylic acid. Furthermore, the polyol acrylate prepolymer can be obtained by esterifying the hydroxyl groups of the polyether polyol with (meth) acrylic acid. These photopolymerizable prepolymers are 1
One kind may be used, or two or more kinds may be used in combination.

On the other hand, an epoxy resin is usually used as the cationically polymerizable photopolymerizable prepolymer. Examples of the epoxy resin include compounds obtained by epoxidizing polyhydric phenols such as bisphenol and novolac resins with epichlorohydrin, compounds obtained by oxidizing linear olefin compounds and cyclic olefin compounds with peroxides, etc. Is mentioned. Further, as the photopolymerizable monomer, for example, 1,4-butanediol di (meth)
Acrylate, 1,6-hexanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, neopentyl glycol adipate di (meth) acrylate, hydroxypivalic acid neopentyl glycol di (meth) ) Acrylate, dicyclopentanyl di (meth) acrylate, caprolactone modified dicyclopentenyl di (meth) acrylate, ethylene oxide modified phosphoric acid di (meth) acrylate, allylated cyclohexyl di (meth) acrylate, isocyanurate di (meth)
Acrylate, trimethylolpropane tri (meth) acrylate, dipentaerythritol tri (meth) acrylate, propionic acid modified dipentaerythritol tri (meth) acrylate, pentaerythritol tri (meth) acrylate, propylene oxide modified trimethylolpropane tri (meth) acrylate Polyfunctional acrylates such as acrylate, tris (acryloxyethyl) isocyanurate, propionic acid-modified dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, caprolactone-modified dipentaerythritol hexa (meth) acrylate . These photopolymerizable monomers may be used alone or in combination of two or more, and may be used in combination with the photopolymerizable prepolymer.

On the other hand, as a photopolymerization initiator optionally used, for radical polymerization type photopolymerizable prepolymers and photopolymerizable monomers, for example, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, Benzoin-n-butyl ether, benzoin isobutyl ether, acetophenone, dimethylaminoacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, 2-hydroxy-2
-Methyl-1-phenylpropan-1-one, 1-hydroxycyclohexyl phenyl ketone, 2-methyl-1
-[4- (Methylthio) phenyl] -2-morpholino-
Propan-1-one, 4- (2-hydroxyethoxy)
Phenyl-2 (hydroxy-2-propyl) ketone, benzophenone, p-phenylbenzophenone, 4,4'-
Diethylaminobenzophenone, dichlorobenzophenone, 2-methylanthraquinone, 2-ethylanthraquinone, 2-tert-butyl-anthraquinone, 2-aminoanthraquinone, 2-methylthioxanthone, 2-
Ethylthioxanthone, 2-chlorothioxanthone,
2,4-dimethyl thioxanthone, 2,4-diethyl thioxanthone, benzyl dimethyl ketal, acetophenone dimethyl ketal, p-dimethyl amine benzoate, etc. are mentioned. Further, as the photopolymerization initiator for the cationic polymerization type photopolymerizable prepolymer, for example, an onium such as an aromatic sulfonium ion, an aromatic oxosulfonium ion, or an aromatic iodonium ion,
Examples thereof include compounds consisting of anions such as tetrafluoroborate, hexafluorophosphate, hexafluoroantimonate and hexafluoroarsenate. These may be used alone or in combination of two or more, and the compounding amount thereof is usually 0 with respect to 100 parts by weight of the photopolymerizable prepolymer and / or the photopolymerizable monomer. It is selected in the range of 0.2 to 10 parts by weight.
Further, in this ionizing radiation curable resin composition, like the thermosetting resin composition described above, if desired, antiglare properties of the hard coat layer, improvement of flexural modulus, stabilization of volume shrinkage,
For the purpose of improving heat resistance and the like, various fillers such as silica, alumina, and hydrated alumina may be added. Further, various additives such as an antioxidant, an ultraviolet absorber, a light stabilizer, an antistatic agent, a leveling agent, an antifoaming agent and the like can be added.

In the present invention, a coating liquid containing the thermosetting resin composition or the ionizing radiation curable resin composition is prepared as the coating liquid for forming the hard coat layer (a).
A suitable organic solvent can be used for the preparation of this coating solution, if necessary. Examples of the solvent used at this time include aliphatic hydrocarbons such as hexane, heptane and cyclohexane, aromatic hydrocarbons such as toluene and xylene, halogenated hydrocarbons such as methylene chloride and ethylene chloride, methanol, ethanol, propanol and butanol. Alcohol, acetone, methyl ethyl ketone, 2-pentanone, ketones such as isophorone, esters such as ethyl acetate and butyl acetate, and cellosolve-based solvents such as ethyl cellosolve. The concentration and viscosity of the coating liquid prepared in this way are not particularly limited as long as they can be coated, and can be appropriately selected depending on the situation. Next, on one surface of the substrate film, the coating solution is applied by a conventionally known method, for example, a bar coating method, a knife coating method, a roll coating method, a blade coating method, a die coating method, a gravure coating method, or the like. When a thermosetting resin composition is used after coating to form a coating film and drying, by heating to cure the coating film, or when using an ionizing radiation curable resin composition For forming a hard coat layer by irradiating with ionizing radiation to cure the coating film. As the ionizing radiation, ultraviolet rays, electron beams, etc. are used as described above. The ultraviolet rays are obtained with a high pressure mercury lamp, a fusion H lamp, a xenon lamp, etc., and the irradiation amount is usually 100 to 500 mJ / cm ² , while the electron beam is obtained with an electron beam accelerator or the like, and the irradiation amount is It is usually 150 to 350 kV. Among these ionizing radiations, ultraviolet rays are particularly suitable. When an electron beam is used, a cured film can be obtained without adding a polymerization initiator.

In the present invention, the hard coat layer (a) thus formed preferably has a pencil hardness of 2H or more. If the hardness is less than 2H, the scratch resistance may be insufficient. The thickness of the hard coat layer is selected within the range of 2 to 20 μm. This thickness is 2 μm
If it is less than 10 μm, the scratch resistance is insufficient, and if it exceeds 20 μm, cracks may occur in the layer (a), which is disadvantageous in terms of productivity. The thickness of this hard coat layer is 2
The range is preferably from 15 to 15 μm, particularly preferably from 3 to 10 μm. The hard coat layer of the layer (a) can be provided with an uneven shape on the surface for the purpose of imparting antiglare properties. To form this uneven shape, for example, after coating a thermosetting or ionizing radiation curable resin composition, a shaped film having an uneven shape is laminated on the surface of this uncured layer, and the uncured layer is thermoset. After the treatment or curing treatment with ionizing radiation, a method of peeling off the shaped film can be used. In the hard coat film of the present invention, as the (b) layer, the refractive index is 1.47 to 1.1 on the surface of the base film opposite to the hard coat layer side of the (a) layer. A cured resin layer by ionizing radiation in the range of 56 is provided. If the refractive index of the layer (b) deviates from the above range, the effect of the present invention for suppressing the yellowish color generated when the ITO films are laminated is not sufficiently exhibited. In the present invention, the thickness of the (b) layer is 2
It is selected in the range of ˜20 μm. If the thickness is less than 2 μm, the hard coat performance is insufficient, and if it exceeds 20 μm, cracks may occur in the layer (b), which is also disadvantageous in terms of productivity. The thickness of this (b) layer is 2
The range is preferably from 15 to 15 μm, particularly preferably from 3 to 10 μm. For the layer (b), an ionizing radiation curable resin composition is used as a coating liquid for forming the layer (b). As the ionizing radiation curable resin composition, the cured resin layer has a refractive index of 1.47 to 1.56 from among the ionizing radiation curable resin compositions described in the hard coat layer of the layer (a).
Those in the range can be appropriately selected and used. The method of forming the layer (b) will be described later.

In the hard coat film of the present invention, as the layer (c) on the layer (b), a curing agent containing a metal oxide and having a refractive index in the range of 1.65 to 1.72 is cured by ionizing radiation. A resin layer is provided. Examples of the metal oxide include fine particles of zirconium oxide, antimony-doped tin oxide (ATO), titanium oxide, tin-doped indium oxide (ITO), tantalum oxide, tin oxide, niobium oxide and the like. These metal oxides are
One kind may be used alone, or two or more kinds may be used in combination, and among these, zirconium oxide and ATO are particularly preferable. The metal oxide having an average particle size in the range of 10 to 200 nm, particularly 10
Those in the range of -80 nm are preferably used. In the present invention, as the content of the metal oxide in the (c) layer, the refractive index of the (c) layer is 1.65 to 1.72.
It is not particularly limited and may be appropriately selected depending on the refractive index of the metal oxide used, the refractive index of the cured resin, etc., but is usually 2 per 100 parts by weight of the cured resin.
It is about 100 to 600 parts by weight. If the refractive index of the layer (c) deviates from the above range, the effect of the present invention for suppressing the yellowish color generated when the ITO films are laminated will not be sufficiently exhibited.
The thickness of the layer (c) is selected in the range of 40 to 250 nm. If the thickness is less than 40 nm, it is difficult to form, and a thick layer exceeding 250 nm is not necessary, which is economically disadvantageous. The preferable thickness of the (c) layer is 40 to
200 nm, more preferred thickness is in the range of 50-150 nm. As the coating liquid for forming the layer (c), an ionizing radiation curable resin composition containing the metal oxide so that the cured resin layer has a refractive index in the range of 1.65 to 1.72. Is used. This ionizing radiation curable resin composition can be appropriately selected and used from the ionizing radiation curable resin compositions described in the hard coat layer of the layer (a).

In the present invention, the formation of the layers (b) and (c) is advantageously performed by the following method. First, the surface of the base film opposite to the hard coat layer side which is the (a) layer is coated with the (b) layer forming coating solution to form a coating film, which is then irradiated with ionizing radiation to form a half film. Cure to a cured state. At this time, when ultraviolet rays are irradiated, the light amount is usually about 50 to 150 mJ / cm ² . Then, the half-cured cured layer thus formed is coated with a coating liquid for forming a layer (c) to form a coating film, which is sufficiently irradiated with ionizing radiation to form the layer (b). Completely cure with. At this time, when irradiating with ultraviolet rays, the light amount is usually 400 to 1000 mJ / cm 2.
It is about ² . In this way, the base film (a)
Layers (b) and (c), which have good interlayer adhesion and excellent hard coat performance, are sequentially formed on the surface opposite to the layer side. The hard coat film of the present invention having such a constitution is obtained by laminating an ITO film on the layer (c) without deteriorating the hard coat performance or impairing the optical properties such as haze value and total light transmittance. In that case, it is possible to suppress the yellowishness that has conventionally occurred, and it is possible to improve the displayability and visibility of an image when used in a touch panel. When the hard coat film of the present invention is used as a touch-side plastic substrate in a touch panel, a transparent conductive thin film is provided on the (c) layer. The transparent conductive thin film is not particularly limited as long as it has transparency and conductivity, and examples thereof include indium oxide, tin oxide, zinc oxide, tin-doped indium oxide (ITO), antimony-doped tin oxide (ATO). ), A zinc-aluminum composite oxide, an indium-zinc composite oxide, a single layer or a laminated structure of two or more layers made of a metal such as gold, silver or copper or an alloy thereof. Among these, the ITO film is preferable from the viewpoints of transparency, conductivity, environmental stability, circuit processability, and the like. The thickness of the transparent conductive thin film is 5 from the viewpoint of film forming property, conductivity, transparency and the like.
The range of -100 nm is preferable, and the range of 15-50 nm is particularly preferable.

The method for forming the transparent conductive thin film is not particularly limited, and may be vacuum deposition method, sputtering method,
A PVD method (physical vapor deposition method) such as an ion plating method, a dry process such as a CVD method (chemical vapor deposition method), or a wet process such as a spray method or a sol-gel method can be used. However, a dry process, particularly a vacuum deposition method and a sputtering method are preferable from the viewpoint of the uniformity of the thin film. When the transparent conductive thin film thus formed is an ITO film, its refractive index is about 2. Therefore, when the ITO film is directly formed on the layer (b) without providing the layer (c), the obtained hard coat film has a yellowish color due to the reflection of light on the short wavelength side. . In the present invention, the layer (c) has a refractive index of 1.6 which is between the refractive index of the ITO film and the layer (b).
By providing the layer in the range of 5 to 1.72, the reflection of light on the short wavelength side is reduced and the formation of yellowish color is suppressed.

[0015]

EXAMPLES The present invention will now be described in more detail with reference to examples, but the present invention is not limited to these examples. The performance of the hard coat film was evaluated according to the following method. (1) Total light transmittance and haze value Haze meter “NDH-200” manufactured by Nippon Denshoku Industries Co., Ltd.
It was measured using "0". (2) Using scratch-resistant steel wool # 0000, (a) the layer surface was rubbed 5 times with a load of 9.8 × 10 ⁻³ N / mm ² and visually observed,
The following criteria were used for evaluation. ○: Not scratched ×: Scratched (3) Transmission b * (Yellowness evaluation) Simultaneous side-light spectroscopic color difference meter “SQ” manufactured by Nippon Denshoku Industries Co., Ltd.
-2000 "was used. The larger the transmission b *, the stronger the yellowness.

Example 1 (1) Mixture of polyfunctional acrylic resin [Arakawa Chemical Industry
Co., Ltd., product name "Beamset 577", solid content concentration 1
00%] to 100 parts by weight of photoinitiator [Ciba Specialty Chemicals Co., Ltd., trade name "Irgacure 18"
4 "] was added and further diluted with toluene so that the total concentration was 50% by weight, to prepare a coating solution for forming a layer (a). Next, a polyethylene terephthalate (PET) film having a thickness of 188 μm [manufactured by Toyobo Co., Ltd.,
Product name "A4300"] is coated on one side with the above-mentioned (a) layer-forming coating solution with a Meyer bar No. 8 so that the thickness after complete curing is 5 μm, and then ultraviolet rays are applied to this. Irradiation was performed with a light amount of 300 mJ / cm ² to form a hard coat layer of layer (a). (2) Mixture of polyfunctional acrylic resin [Arakawa Chemical Industry
Co., Ltd., product name "Beamset 577", solid content concentration 1
00%] to 100 parts by weight of photoinitiator [Ciba Specialty Chemicals Co., Ltd., trade name "Irgacure 18"
4 "] was added and further diluted with toluene so that the total concentration was 50% by weight, to prepare a coating solution for forming layer (b). Next, on the surface opposite to the hard coat layer formed in the step (1), the above-mentioned (b) layer forming coating solution was applied to a Meyer bar No. 8 so that the thickness after complete curing would be 5 μm. After applying it, apply ultraviolet light to it 8
Irradiate with 0 mJ / cm ² to cure to half cure state,
A hard coat layer was formed. (3) Zirconium oxide-containing UV-curable acrylic coating agent [manufactured by JSR Corporation, trade name "Desolite KZ725"
2C ", zirconium oxide having an average particle size of 70 nm, and a solid content of 46% by weight] were diluted with isobutyl alcohol to prepare a coating solution for forming a layer (c) having a solid content of 2% by weight.
Next, the above-mentioned (c) layer-forming coating liquid is applied onto the half-cured hard coat layer formed in the step (2).
After applying with Meyer bar No.3 so that the thickness after complete curing would be 70 nm, the amount of ultraviolet light was 500 mJ.
/ Cm ² irradiation to completely cure together with the hard coat layer in the half-cure state, and the (b) layer having a refractive index of 1.53 and the refractive index of 1.3 on the surface of the PET film opposite to the (a) layer. 6
The layer (c) of 9 was sequentially formed to prepare a desired hard coat film. The performance of this hard coat film is shown in Table 1. An ITO film having a thickness of 30 nm was formed on the layer (c) by sputtering, and the transmission b * value of this hard coat film was measured. The results are also shown in Table 1. The refractive index of the ITO film is 2.

Example 2 In the same manner as in Example 1, except that the coating liquid shown below was used in place of the coating liquid for forming layer (c) in the step of Example 1 (3). , A hard coat film was produced. The layer (c) had a thickness of 70 nm and a refractive index of 1.68. The performance of this hard coat film and the transmission b of the hard coat film provided with the ITO film as in Example 1.
* Is shown in Table 1. <Preparation of coating liquid for forming layer (c)> Dispersion liquid of antimony tin oxide (ATO) [manufactured by Dainippon Ink and Chemicals, Inc.,
Product name "TA-01D", ATO average particle size 60 nm,
Solid content concentration 10% by weight] 100 parts by weight, ultraviolet curable acrylic resin [manufactured by Dainichiseika Kogyo Co., Ltd., trade name "SEICA BEAM EXF-01L (NS)", solid content concentration 100
%] 3.3 parts by weight, and further diluted with isobutanol so that the total solid content concentration becomes 2% by weight,
(C) A layer forming coating liquid was prepared.

Comparative Example 1 The procedure of Example 1 was repeated except that the step (3) was not performed and the layer (c) was not provided.
A hard coat film was produced. The performance of this hard coat film is shown in Table 1. Further, an ITO film having a thickness of 30 nm is formed on the layer (b) by sputtering,
The transmission b * value of this hard coat film was measured. The results are also shown in Table 1. Comparative Example 2 Hard coating was carried out in the same manner as in Example 1 except that the coating liquid shown below was used in place of the coating liquid for layer formation (c) in the step of Example 1 (3). A film was made. The layer (c) had a thickness of 70 nm and a refractive index of 1.74. The performance of this hard coat film and the transmission b of the hard coat film provided with the ITO film as in Example 1.
* Values are shown in Table 1. <(C) Preparation of coating liquid for layer formation> Titanium oxide dispersion liquid [Dainippon Ink and Chemicals, Inc., trade name "TF-14D",
To 100 parts by weight of titanium oxide having an average particle size of 60 nm and a solid content concentration of 10% by weight, an ultraviolet curable acrylic resin [manufactured by Dainichiseika Kogyo Co., Ltd., trade name "SEICA BEAM EXF-01"
L (NS) ", solid content concentration 100%] 2.5 parts by weight, and further diluted with isobutanol so that the total solid content concentration becomes 2% by weight, and the coating for forming layer (c). A liquid was prepared. Comparative Example 3 Hard coating was performed in the same manner as in Example 1 except that the coating liquid shown below was used in place of the coating liquid for forming layer (c) in the step of Example 1 (3). A film was made. The layer (c) had a thickness of 70 nm and a refractive index of 1.62. The performance of this hard coat film and the transmission b of the hard coat film provided with the ITO film as in Example 1.
* Values are shown in Table 1. <(C) Preparation of Layer-Forming Coating Liquid> Antimony Pentoxide-Containing UV-Curable Acrylic Resin [Catalyst Kasei Kogyo Co., Ltd., trade name "ELCOM P-4575", average particle size of antimony pentoxide 40 nm, Solid content concentration of 30% by weight] so that the total solid content concentration becomes 2% by weight.
-(C) Layer forming coating liquid was prepared by diluting with propanol.

[0019]

[Table 1]

[0020]

The hard coat film of the present invention is used for a touch side plastic substrate in a touch panel, and by providing a refractive index adjusting layer,
Without deteriorating the hard coat performance, or without impairing the optical properties such as haze value and total light transmittance,
It is possible to suppress the yellowishness that has been conventionally generated when the ITO films are laminated, and it is possible to improve the image displayability and the visibility of the touch panel.

Continued front page    F-term (reference) 4F100 AA17D AA17H AA27D AA27H                       AA28D AA28E AA28H AA29D                       AA29H AA33D AA33E AA33H                       AK01A AK01C AK01D AK25                       AK42 BA04 BA05 BA10B                       BA10D BA10E CA23D CA30                       CC02B EH66E GB41 JB14C                       JB14D JK12B JN18C JN18D                       JN28 YY00B YY00C YY00D

Claims (3)

[Claims] 1. A substrate having a thickness (a) of 2 on one surface thereof.
Having a hard coat layer having a thickness of 20 μm to 20 μm, and (b) having a refractive index in the range of 1.47 to 1.56 and having a thickness of 2 to 20 μm, which is cured by ionizing radiation, and (c) a metal. A hard coat film comprising an oxide-containing refractive index in the range of 1.65 to 1.72 and a cured resin layer having a thickness of 40 to 250 nm, which is sequentially cured by ionizing radiation. 2. The hard coat film according to claim 1, wherein the metal oxide in the layer (c) is zirconium oxide and / or antimony-doped tin oxide. 3. The hard coat film according to claim 1, which further comprises a tin-doped indium oxide film having a thickness of 5 to 100 nm on the layer (c).