JP2001035261A - Transparent conductive layered product and transparent tablet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a transparent conductive layered product having superior visibility, a transparent conductive layer having satisfactory abrasion resistance, low reflectance and light scattering on the surface of the transparent conductive layer, while being especially useful for a tablet. SOLUTION: A transparent conductive layer is provided on the uppermost surface of this transparent conductive layered product with a curing resin layer, placed interveningly placed as necessary on at least one face of a base of an organic high polymer, and optically fine irregular parts are finely formed on the base coming into contact with the transparent conductive layer and/or on the surface coming into contact with the transparent conductive layer in the curing resin layer in this transparent conductive layered product. In this case, the average reflectance of the surface provided with the transparent conductive layer in a wavelength region of 450-650 nm is not more than 5.5%, and a haze value is not more than 10%.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transparent conductive laminate, and more particularly, to a transparent conductive laminate having a low reflectance on the surface of a transparent conductive layer and excellent abrasion resistance of the transparent conductive layer.
And a transparent tablet using the transparent conductive laminate as at least one transparent electrode substrate.

[0002]

2. Description of the Related Art In recent years, portable information devices equipped with a liquid crystal display for displaying information and a transparent tablet for inputting information (also referred to as touch switches, touch panels, and flat switches) have begun to be widely used. The resistive film type transparent tablet, which is often used as a transparent tablet, is composed of two transparent electrode substrates with a transparent conductive layer formed facing each other at an interval of about 10 μm. The two electrodes contact each other to operate as a switch. For example, menu selection on a display screen or input of a figure or a handwritten document can be performed.

As such a transparent electrode substrate, for example, a transparent conductive material made of a metal oxide such as indium oxide (ITO) or zinc oxide containing tin oxide is formed on a substrate such as glass or various thermoplastic polymer films. Layered layers are widely used.

Here, the transparent tablet is often arranged on various displays such as a liquid crystal display device and a CRT. However, if light is greatly reflected when the light passes through the transparent tablet, the contrast of the display screen is high. It is not preferable because it causes a decrease in brightness and the like.

[0005]

As a method of reducing the reflectivity of the transparent electrode surface, a method of laminating a layer having an appropriate optical interference (optical interference layer) on the underlayer of the transparent conductive layer has been proposed by the present applicant. For example, Japanese Patent Application Laid-Open No. 8-216327
And Japanese Patent Application Laid-Open No. Hei 10-24516.

[0006] In the transparent conductive laminate according to these proposals, the reflectance of the surface of the transparent conductive layer is reduced, and the visibility of tablets and displays is improved. However, when such a transparent conductive laminate is used for applications such as a transparent tablet, it has been observed that the abrasion resistance of the transparent conductive layer against mechanical deformation due to writing input to the tablet becomes insufficient. That is, in the application of the transparent conductive laminate to a wider field, it has been desired to improve these mechanical properties.

An object of the present invention is to provide a transparent conductive laminate which has excellent visibility and is particularly useful as a tablet, has a low reflectance and light scattering property on the surface of the transparent conductive layer, and has good abrasion resistance of the transparent conductive layer. Is to provide the body.

[0008]

Means for Solving the Problems The present inventors have developed a transparent conductive layer on a surface on which optically fine irregularities having a size of about 1/2 or less of the wavelength of light are formed densely and uniformly. Is provided, the reflectance of the surface of the transparent conductive layer is effectively reduced,
It has been found that application to a wide range of fields such as tablets can be expected.

That is, the present invention provides a transparent conductive laminate comprising a transparent conductive layer provided on the outermost surface of at least one surface of an organic polymer substrate via a cured resin layer, if necessary. A transparent conductive laminate in which optically fine irregularities are densely formed on a surface of the cured resin layer and the substrate and / or the cured resin layer which is in contact with the transparent conductive layer; Wavelength 450 ~
The average reflectance in the region of 650 nm is 5.5% or less;
A transparent conductive laminate having a haze value of 10% or less.

[0010] Further, in one structure of the transparent conductive laminate of the present invention, the projections in the irregularities have an average diameter of about 50 to 50.
The transparent conductive laminate according to the present invention is characterized in that the transparent conductive laminate is formed so as to include at least a part of 300 nm fine particles, and the fine particles are fixed by a binder. It is assumed that.

Further, one of the structures of the transparent conductive laminate of the present invention is characterized in that the binder is mainly composed of a condensate of silicon alkoxide.

Further, in one construction of the transparent conductive laminate of the present invention, a protective layer having a predetermined solvent resistance and / or a hard coat property is laminated on one or both sides of an organic polymer molded substrate. It is characterized by the following.

Further, in one construction of the transparent conductive laminate of the present invention, at least the protective layer laminated on the surface on which the transparent conductive layer is laminated is composed of a metal alkoxide and / or a condensate thereof in a weight ratio of 20%. %, And in particular, the metal alkoxide is a silicon alkoxide.

The present invention also includes a transparent tablet using the transparent conductive laminate as at least one transparent electrode substrate of a transparent tablet in which two transparent electrode substrates are arranged with their electrode surfaces facing each other. It is a thing. Hereinafter, the present invention will be described in more detail.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION In the transparent conductive laminate of the present invention, a transparent conductive layer is provided on the outermost surface on one side of a substrate made of an organic polymer, and the transparent conductive layer has an average reflection in a wavelength range of 450 to 650 nm. Rate is 5.5% or less and haze value is 1
0% or less. As described above, the transparent conductive laminate suitable as a tablet having a low average reflectance and a low light scattering property, that is, a small haze value, has an optical surface on a substrate or a cured resin layer in contact with the transparent conductive layer. The fine irregularities are uniformly and densely formed.

The unevenness is preferably a smoothly continuous curved surface such as a spherical surface or an elliptical spherical surface, and it is important that the curvature is not too small. If the convex shape has a remarkable angle or a portion with a very small curvature, the transparent conductive layer laminated on those portions will not be able to follow the surface shape, resulting in voids or cracking due to external force This is not preferred because the resistance to abrasion of the transparent conductive layer often decreases.

Such optically fine irregularities are densely formed on the surface in contact with the transparent conductive layer, so that the haze value is 10% or less, preferably 5% or less, and the irregularities are dense. By being provided, the reflectance is approximately 5.5.
% Or less, and a transparent tablet excellent in visibility can be realized. When such a fine convex shape is not formed, the average reflectance in the visible region of the conductive layer surface, particularly in the region of wavelength 450 to 650 nm, usually shows a high value exceeding 7%, and the haze value also increases. As described above, when used for transparent tablet applications, visibility is deteriorated. In addition, the reflectance increases if the fineness is lacking.

On the surface on which the transparent conductive layer is laminated,
If this is considered as one layer of the surface where the convex shape having a size of about 1/2 or less of the wavelength of light is uniformly formed at a sufficiently high density, the medium through which light passes contains a micro air layer. It can be considered as a non-uniform mixed layer, where the refractive index of the layer is reduced based on the air content in the layer, which reduces the reflectivity of the surface and the transparent layer provided on such a layer It is presumed that the transparent conductive laminate having low light scattering and low reflectance as described above is formed by the action of the refractive index of the conductive layer and the refractive index of the substrate made of an organic polymer.

That is, the transparent conductive laminate of the present invention has a visible region on the surface of the conductive layer, in particular, a wavelength of 450 to 650.
The average reflectance in the region of nm is 5.5% or less.
It has an optically fine and fine uneven surface in contact with the conductive layer, and has an optically fine uneven surface in contact with the conductive layer such that the haze value is 10% or less.

There are several methods for forming the surface having the above-mentioned uneven shape.
(1) a method in which a layer comprising fine particles and a binder is provided on a substrate, (2) a method in which a molded body containing fine particles is used as a substrate,
(3) hot press processing using a mold having surface irregularities,
(4) A transfer molding method using a mold having surface irregularities, and the like. Here, the above-mentioned unevenness will be described below with the above (1) as a representative example.

The layer composed of the fine particles and the binder of the above (1) is formed, for example, by applying a coating liquid in which a curable resin containing the fine particles is dispersed in an appropriate solvent as required, and then dried. (1-2) on the substrate,
It can be prepared by a method of laminating a polymer film containing fine particles by lamination or the like.
The method 1) has the advantage that the method 1) is simple, and the height and spacing of the convex shapes can be finely controlled by controlling the mixing ratio of the fine particles and the binder, the coating solution concentration, the coating thickness, and the like.

The optically fine and dense concave and convex shapes formed by the method can be, for example, an array form as shown in FIGS. The two convex portions at adjacent positions are arranged so as to be in full contact with each other when the fine particles are completely in contact with each other (FIG. 1), or the length of the bottom of the convex portion (equal to the approximate diameter) or less. (FIGS. 2 and 3).

Here, the length of the bottom of the projection is defined as b in FIG. The range of the length of the bottom b is 50
~ 200 nm is preferred.

In FIG. 4, the height a of the projection (the height of the projection protruding from the surface) is in the range of 30 to 100 nm, and the distance between adjacent projections is 50 to 3 on average.
It is preferably in the range of 00 nm. Here, the average distance between the protrusions refers to the distance between the tops of the protrusions. Further, the projections in the unevenness are substantially uniformly and continuously formed on the surface, that is, the average distance between the projections is basically 50 to 30 so that the projections are formed in an area of at least half of the surface in contact with the transparent conductive layer.
Preferably, the thickness is set to 0 nm. As long as the average reflectance and the haze value are within the ranges satisfying the above characteristics, there may be some portions where the distance between the convex portions is outside this range on some surfaces.

If the above-mentioned preferred range is not satisfied, there may be disadvantages such as an insufficient effect of reducing the reflectance and an increase in light scattering (haze) due to the projections.

Further, in the uneven portion, the volume of the fine particles substantially buried in the binder is preferably about 40 to 90%, more preferably 50 to 80% of the total volume of the fine particles. Here, “substantially” means excluding a state in which the fine particles are covered with the binder in a thin skin shape. If the burial ratio exceeds 90%, the fine particles are almost buried in the binder, and a preferable convex shape is not formed. If the burial ratio is less than 40%, the fixing power of the fine particles into the layer by the binder is insufficient. This is not preferable because the layer may be insufficient, the wear resistance of the layer may be reduced, or the transparent conductive layer may not sufficiently follow the convex shape and may form voids.

Next, typically, one of the specific methods (1) for forming a layer composed of fine particles and a binder is as follows.
1) A method of applying a coating liquid in which a curable resin containing fine particles is dispersed in an appropriate solvent as required and drying the resin to cure the resin will be described below.

Suitable fine particles for the above purpose include spherical fine particles having an average particle diameter (diameter) of about 50 to 300 nm. 30 nm if the particle size of the fine particles is less than 50 nm
It becomes difficult to form a convex portion having the above height, and the particle size is 3
If it exceeds 00 nm, it is difficult to reduce the distance between the centers of the projections to 300 nm or less, which is not preferable.

Examples of the material of the fine particles include fine particles of metal oxides such as silicon oxide and aluminum oxide, fine particles obtained by hydrolyzing, condensing, and firing metal alkoxides, fine particles of acrylic and polystyrene, and the like. Examples thereof include fine particles crosslinked in the presence of an acid, and fine particles previously dispersed in a solvent such as water or an organic solvent as necessary are preferably used.

The curable resin serving as a binder for fixing such fine particles is not particularly limited, and examples thereof include polyfunctional acrylates and condensates of metal alkoxides.
Among them, a silicone-based thermosetting resin mainly composed of a condensate obtained by subjecting a silicon alkoxide to a hydrolysis and a (partial) condensation reaction, particularly as a starting material, is most preferably used for obtaining high hardness.

Here, as the silicon alkoxide, for example, tetramethoxysilane, tetraethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, dimethyldimethoxysilane, γ-glycidoxypropyltrimethoxysilane, β- (3,4 epoxy Cyclohexyl) ethyltrimethoxysilane, vinyltrimethoxysilane, N-β (aminoethyl) γ-aminopropyltrimethoxysilane, N-β (aminoethyl) γ-aminopropylmethyldimethoxysilane, γ-aminopropyltriethoxysilane, Examples thereof include acryloylpropyltrimethoxysilane and methacryloylpropyltrimethoxysilane, and one or more of these silicon alkoxides may be used in combination. These silicon alkoxide resins may be partially or wholly hydrolyzed and partially condensed under appropriate conditions. These silicon alkoxide resins are hydrolyzed and (partially) condensed in the presence or absence of a catalyst and a solvent to cure to form a polysiloxane resin.

That is, the fine particles are added to the curable resin,
Prepare a coating liquid dispersed by adding an appropriate diluting solvent as needed, apply it on a substrate or a protective layer described below, and heat and irradiate ultraviolet rays to dry and cure the curable resin. Thereby, the uneven surface in contact with the transparent conductive layer can be formed.

Examples of the coating method include a microgravure coating method, a Meyer bar coating method, a direct gravure coating method, a reverse roll coating method, a curtain coating method, a spray coating method, a comma coating method, a die coating method, a knife coating method, and a spin coating method. Various coating methods such as a coating method are used.

Examples of the diluting solvent include alcohol solvents and hydrocarbon solvents such as ethanol, isopropyl alcohol, butanol, 1-methoxy-2-propanol, and the like.
Hexane, cyclohexane, ligroin and the like are preferred, but other polar solvents such as xylene, toluene, cyclohexanone, methyl isobutyl ketone, and isobutyl acetate can also be used. These can be used alone or as a mixture of two or more solvents.

The cured resin layer containing the fine particles thus obtained usually has a thickness of 20 to 200 nm (corresponding to d in FIG. 4). The size of the film thickness is selected in consideration of the size of the fine particles to be used.

When the transparent conductive laminate of the present invention is used for an electrode substrate of a transparent tablet, the surface on which the transparent conductive layer is formed has a predetermined hard coat property and solvent resistance. Is preferred. That is, the hard coat property is necessary for improving the abrasion resistance of the transparent conductive layer, and the solvent resistance is often required in the step of patterning the transparent conductive layer or the step of printing a conductive paste or the like. Also, on the surface opposite to the surface on which the transparent conductive layer is formed, a hard coat property capable of withstanding mechanical deformation caused by input to the tablet, and an organic material used as an adhesive when bonding with another substrate. In many cases, solvent resistance that can withstand the solvent is required.

For these purposes, it is preferable that a protective layer having a predetermined solvent resistance and / or a hard coat property is laminated on one or both surfaces of a substrate made of an organic polymer as described below.

Organic solvent resistance: A few drops of toluene (special grade, manufactured by Wako Pure Chemical Industries, Ltd.) typified as a solvent for a silver paste that is printed on the transparent conductive layer when a tablet is prepared, are dropped at 25 ° C. After visual observation of changes in appearance such as cloudiness, swelling and dissolution of the surface after standing for 3 minutes, and when no change is confirmed, it is determined that the composition has organic solvent resistance.

Alkali-resistant aqueous solution resistance: A few drops of a 3.5 wt% aqueous sodium hydroxide solution used for dissolving a resist at the time of patterning the transparent conductive layer is dropped on the sample surface, and the temperature is 25 ° C.
After standing for 3 minutes, changes in the appearance such as cloudiness, swelling, and dissolution of the surface are visually observed, and if no change is confirmed, it is determined to have alkali-resistant aqueous solution resistance.

Acid-resistant aqueous solution: Several drops of an etchant (a mixture of 35 wt% ferric chloride aqueous solution, 35 wt% hydrochloric acid and water in a ratio of 1: 1: 10) used for patterning the transparent conductive layer are applied to the sample surface. After dripping and leaving at 25 ° C. for 3 minutes, changes in the appearance such as cloudiness, swelling, and dissolution of the surface are visually observed. If no change is observed, it is determined that the composition has acid-resistant aqueous solution resistance.

Hard coat property: When the pencil hardness of the sample surface specified by Japanese Industrial Standard K5400 is 2B or more, more preferably F or more, and most preferably 2H or more, the surface is judged to have hard coat property. I do.

As a method for forming a protective layer having such characteristics, for example, a method in which a curable resin is applied by coating or the like and cured by heating or irradiation with actinic rays,
And a method using a vacuum process such as sputtering, vacuum deposition, or vapor phase growth (CVD). Examples of such a curable resin include an acrylic, phenoxy, or epoxy thermosetting resin, a silicon alkoxide condensation-curable resin, and an actinic ray-curable resin using a polyfunctional (meth) acrylate. Among them, a condensation-curable resin of silicon alkoxide and an actinic ray-curable resin based on polyfunctional (meth) acrylate are preferably used. An actinic ray-curable resin using such a polyfunctional (meth) acrylate is mixed with a metal alkoxide such as silicon, aluminum, titanium, or zirconium (which generally functions as a coupling agent) and / or a condensate of silicon alkoxide. It is also preferred. The content of the metal alkoxide and / or silicon alkoxide condensate mixed at this time is more preferably 20% or more in terms of weight ratio from the viewpoint of improving the chemical bonding force described below.

Since the protective layer contains the same type of material as the layer composed of the fine particles and the binder, the chemical bonding force between the two layers is increased, and the protective layer is formed of the layer composed of the fine particles and the binder and the layer laminated on the layer. The abrasion resistance of the transparent conductive layer is improved. This is one of the great features of the present invention.

As the silicon alkoxide suitably used here, it is preferable to use a mixture of two or more silicon alkoxides having 2 to 4 functionalities, more preferably 3 to 4 functionalities. Which are appropriately oligomerized by hydrolysis and dehydration condensation are also preferably used.

Specific examples of these silicon alkoxides include, for example, tetramethoxysilane, tetraethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, dimethyldimethoxysilane, γ-glycidoxypropyltrimethoxysilane, β- (3, 4 epoxycyclohexyl) ethyltrimethoxysilane, vinyltrimethoxysilane, N-β (aminoethyl) γ-aminopropyltrimethoxysilane, N-β (aminoethyl) γ-
Examples thereof include aminopropylmethyldimethoxysilane, γ-aminopropyltriethoxysilane, acryloylpropyltrimethoxysilane, acryloylpropylmethyldimethoxysilane, methacryloylpropyltrimethoxysilane, and methacryloylpropylmethyldimethoxysilane.

The layer containing these silicon alkoxides can further increase the degree of crosslinking by irradiating the coating film with actinic rays such as ultraviolet rays as necessary.

The actinic ray-curable resin refers to a resin whose crosslinking proceeds by irradiation with actinic rays such as ultraviolet rays or electron beams, and is a polyfunctional resin having two or more acryloyl groups or methacryloyl groups in a unit structure. An acrylic resin containing an acrylate component and a methacrylate component in the resin composition is exemplified. For example, trimethylolpropane triacrylate, trimethylolpropane ethylene oxide modified triacrylate, trimethylolpropane propylene oxide modified triacrylate,
Various acrylate monomers such as isocyanuric acid ethylene oxide-modified triacrylate, pentaerythritol tetraacrylate, dipentaerythritol pentaacrylate, dipentaerythritol hexaacrylate, dimethylol tricyclodecane diacrylate, and polyester-modified or urethane-modified, epoxy-modified polyfunctional Acrylate oligomers and the like are preferably used for this purpose.

These resins may be used in a single composition or in a mixture of several kinds. As described above, a condensate of metal alkoxide and / or silicon alkoxide accounts for 20% or more of the total composition. It is preferable to mix at a weight ratio.

When the resin is crosslinked by irradiation with ultraviolet rays, a known photoreaction initiator is added in an appropriate amount.
Examples of the photoreaction initiator include diethoxyacetophenone and 2-methyl-1- {4- (methylthio) phenyl}.
Acetophenone compounds such as -2-morpholinopropane, 2-hydroxy-2-methyl-1-phenylpropan-1-one and 1-hydroxycyclohexylphenyl ketone; benzoin compounds such as benzoin and benzyldimethylketal; benzophenone and benzoyl Benzophenone compounds such as benzoic acid; thioxanthone, 2,
And thioxanthone compounds such as 4-dichlorothioxanthone.

The thickness of the protective layer is about 0.05 to 20 μm.
m, more preferably in the range of 1 to 10 μm. In addition, these protective layers may be used as they are as the cured resin layer containing the fine particles, but are usually provided as a lower layer of the cured resin layer containing the fine particles.

These protective layers are laminated on the substrate directly or via an appropriate intermediate layer. As such an intermediate layer, for example, a primer layer having a function of improving the adhesion between the protective layer and the substrate, and various phase compensation layers such as a layer having a three-dimensional refractive index characteristic having a negative K value to be described later, A layer having a viscoelastic property for relaxing applied stress (vertical stress, horizontal stress), for example, a layer having a storage elastic modulus of about 1 kg / mm ² or less at around room temperature, or a function of preventing permeation of moisture and air. Alternatively, a layer having a function of absorbing moisture or air, a layer having a function of absorbing ultraviolet light or infrared light, a layer having a function of reducing the chargeability of a substrate, or the like is preferably used. The thickness of such an intermediate layer is about 0.1 to
It is preferably in the range of 100 μm.

The method of applying the protective layer to the substrate is as follows.
Using a coating solution obtained by dissolving a precursor composition of the above various resin cured products and a small amount of additives (various fillers, leveling agents, etc.) in an appropriate organic solvent, apply the composition onto a body, and then irradiate with radiation. The layer is crosslinked by heat treatment or the like. The surface of the protective layer may be appropriately roughened in some cases, thereby providing a function of preventing the occurrence of Newton rings in transparent tablet applications.

Examples of the coating method include microgravure coating, Meyer bar coating, direct gravure coating, reverse roll coating, curtain coating, spray coating, comma coating, die coating, knife coating, spin coating, and the like. Various coating methods such as a coating method are used.

Examples of the diluting solvent include alcohol and hydrocarbon solvents such as ethanol, isopropyl alcohol, butanol, 1-methoxy-2-propanol, and the like.
Hexane, cyclohexane, ligroin and the like are preferred, but other polar solvents such as xylene, toluene, cyclohexanone, methyl isobutyl ketone, and isobutyl acetate can also be used. These can be used alone or as a mixture of two or more solvents.

Incidentally, the transparent conductive layer in the present invention includes:
A layer mainly composed of a metal oxide is preferably used, and from the viewpoint of reduction in tablet power consumption and circuit processing,
It is preferable to use a transparent conductive layer having a surface resistance value of 100 to 2000 Ω / □, more preferably 150 to 2000 Ω / □. The thickness of the transparent conductive layer is 12 to 30.
nm is preferred. If it is less than 12 nm, the stability of the resistance value with time tends to be inferior, and if it exceeds 30 nm, the reflectance of the surface on which the transparent conductive layer is laminated increases, which is not preferable.

Specifically, for example, a layer made of tin oxide, indium oxide, zinc oxide, gallium oxide, or the like and a layer made of a material obtained by mixing them at an appropriate ratio are preferably used. A layer made of a material to which one or more kinds of titanium oxide, aluminum oxide, zirconium oxide and the like are added at a ratio of about several weight% is preferably used.

These transparent conductive layers are formed by a sputtering method,
Lamination can be performed using a known vacuum film forming process such as an ion plating method, a vacuum deposition method, and a CVD method.
Among them, the sputtering method is preferable from the viewpoint of the film thickness uniformity and the composition uniformity in the width direction and the length direction.

The substrate made of an organic polymer according to the present invention is not particularly limited. However, it is preferable that the substrate has high transparency, and specifically, it is preferable that the substrate be in the visible region, particularly at a wavelength of 4 nm.
It is preferable that the average value of the transmittance in the region of 50 to 650 nm is at least 80% or more, more preferably 85% or more.

When the transparent conductive laminate of the present invention is used as an input-side transparent electrode substrate (movable electrode substrate) of a pair of transparent electrode substrates constituting a transparent tablet, it is appropriately applied to an external input such as a pen. Preferably, it has some degree of flexibility so as to be deformed. For this reason, a film-shaped molded substrate made of a thermoplastic polymer is preferably used as the substrate made of an organic polymer. Specific organic polymers include, for example, polyethylene terephthalate, polyethylene naphthalate, polycarbonate and polyarylate, polyethersulfone, triacetylcellulose, diacetylcellulose, various polyolefins, and modified products of these or other materials. Copolymers and the like are preferably exemplified. These film-shaped molded substrates are suitably molded by a general melt extrusion method or a solution casting method, but if necessary, the molded film-shaped substrate is subjected to uniaxial stretching or biaxial stretching to be mechanically It is also preferable to increase the strength or enhance optical functions such as a phase difference plate (1/4 wavelength plate, three-dimensional phase difference control plate, etc.).

The thickness of the thus obtained electrode substrate suitable as a movable electrode substrate is about 10 to 400 μm.
m, more preferably in the range of 20 to 200 μm, from the viewpoint of tablet operating characteristics, lightness, lightness, etc.

In the case where the transparent conductive laminate of the present invention is used for a transparent electrode substrate (fixed electrode substrate) used in opposition to the movable electrode substrate, it is not always necessary to have high flexibility. Depending on the form, it may be necessary to have a property (high rigidity) with less deformation against external force. Therefore, in addition to the film-shaped molded substrate made of the thermoplastic polymer, a similar thermoplastic polymer is used. Alternatively, a film or sheet-shaped molded substrate made of a thermosetting resin and / or an ultraviolet curable resin of various materials such as an epoxy-based or acrylic-based material can be suitably used. still,
Examples of the method for forming such a molded substrate include a melt extrusion method, a solution casting method, an injection molding method, and a cast polymerization molding method.

In some cases, a film-shaped or sheet-shaped molded substrate, on which a transparent electrode is not formed, is attached to a surface of the film-shaped molded substrate opposite to the transparent electrode surface, and is backed. An electrode substrate having such a configuration is also preferably used.

The thickness of the thus obtained electrode substrate suitable as a fixed electrode substrate is about 10 to 2000 μm.
m, more preferably 50 to 1000 μm, and most preferably 70 to 700 μm.

In recent years, a new type of transparent tablet having a structure in which a polarizing plate is laminated on the input side (user side) of the tablet has been developed. The advantage of this configuration is that the reflectance of extraneous light inside the tablet can be reduced by half or less mainly due to the optical action of the polarizing plate.

Here, when used for such a type of tablet, since polarized light passes through the transparent electrode substrate,
It is preferable to use a substrate having excellent optical isotropy as the substrate. Specifically, the refractive index in the slow axis direction of the substrate is nx, the refractive index in the fast axis direction is ny, and the thickness of the substrate is d ( n
m), the in-plane retardation Re represented by Re = (nx−ny) × d (nm) is at least 30 nm.
Or less, more preferably 20 nm or less. Here, the value of the in-plane retardation of the substrate is a multi-wavelength birefringence index measuring device (trade name “M-
150 ") at a wavelength of 590 nm.

Among the substrates exhibiting such excellent optical isotropy, the organic polymer constituting the substrate particularly useful as the movable electrode substrate includes, for example, polycarbonate, amorphous polyarylate, and polyether. Sulfone,
Examples include molded products of triacetyl cellulose, diacetyl cellulose, amorphous polyolefins, modified products thereof or copolymers with other materials, and thermosetting resins and ultraviolet curing resins of organic materials such as epoxy and acrylic. However, from the viewpoints of moldability, production cost, thermal stability and the like, polycarbonate, amorphous polyarylate, amorphous polyolefin and modified products of these or copolymers with different materials are most preferred.

Particularly, as the bisphenol component of the polycarbonate, for example, bisphenol A, (3,3,5
-) 1,1-di (4-phenol) cyclohexylidene, 3,3,5-trimethyl-1,1-di (4-phenol) cyclohexylidene, fluorene-9,9-di (4-phenol) And fluorene-9,9-di (3-methyl-4-phenol). These components may be used alone or in combination of two or more for copolymerization or blending. The average molecular weight is preferably in the range of about 15,000 to 100,000. Preferred examples of these polycarbonates include "Panlite" manufactured by Teijin Chemicals Ltd. and "Apec HT" manufactured by Bayer.

Examples of the amorphous polyarylate include commercial products such as "Elmec" manufactured by Kaneka Corporation, "U Polymer" manufactured by Unitika, and "Isalil" manufactured by Isonova.

Examples of the amorphous polyolefin include "ZEONEX" manufactured by Nippon Zeon and "ARTON" manufactured by Nippon Synthetic Rubber.

Examples of the method of forming a film formed from these organic polymer materials include a melt extrusion method, a solution casting method, and an injection molding method, but excellent optical isotropy is obtained. From the viewpoint, it is particularly preferable to perform the forming by using the solution casting method.

In the use of a tablet of the type in which polarized light passes through the transparent conductive substrate exemplified above, the value of the in-plane retardation of the transparent conductive substrate is very important. When the original refractive index characteristic, that is, the refractive index in the thickness direction of the substrate is nz, K =
The K value represented by {(nx + ny) / 2-nz} × d is at least -250 to +150 nm, more preferably -2.
It is preferable that it is in the range of 00 to +100 nm in order to obtain a viewing angle characteristic with high visibility of the tablet.

The present invention also relates to a transparent tablet using the transparent conductive laminate as at least one electrode substrate. Here, when the transparent conductive laminate of the present invention is used for a pair of electrode substrates of a tablet, that is, both a movable electrode substrate and a fixed electrode substrate, the effect intended by the present invention becomes particularly remarkable. The effect can be obtained even if it is used for only one of the fixed electrode substrate. For example, it is possible to obtain good visibility even in a tablet configuration using a transparent electrode laminate of the present invention for a movable electrode substrate and a glass electrode substrate having a transparent electrode formed on a conventional glass plate for a fixed electrode substrate. it can.

[0073]

Embodiments of the present invention will be described below. The evaluation of various characteristics in the following examples and comparative examples was performed in the following manner.

Haze: Measurement was performed using a measuring instrument (trade name “COH-300A”) manufactured by Nippon Denshoku Industries Co., Ltd.

Average reflectance: Hitachi spectrophotometer U3500
The reflectance of the sample in the wavelength range of 450 to 650 nm was measured in the integrating sphere measurement mode, and the geometric average value was used as the average reflectance value. The angle of incidence of the measurement light on the sample is 10
On the back side of the sample, a light-shielding layer was formed using a commercially available black spray, and the measurement was performed in a state where the back side of the sample and the incidence of light from the back side were hardly observed.

Solvent resistance: Performed according to the method described in the specification.

Coating adhesion: A cross cut tape test was performed in accordance with Japanese Industrial Standard K5400. Hard coat property: 1 according to Japanese Industrial Standard K5400
The pencil hardness under a kg load was measured.

Steel wool abrasion: using # 0000 steel wool, the sample surface was 100 gf / c
The degree of scratches on the sample surface when worn under m ² and 10 reciprocating conditions was evaluated as follows. A: No scratch is formed. B: About 5 to 10 scratches per 1 cm width. C: About 20 scratches per 1 cm width. D: About 40 scratches per 1 cm width. E:
More than 60 scratches per cm width.

Refractive index: Measured by Abbe refractometer.

Example 1 First, a random copolymerization of polymethyl methacrylate and γ-methacryloxypropyltrimethoxysilane (Shin-Etsu Chemical KBM503) at a molar ratio of 9: 1 obtained by a reaction according to a conventional method was carried out by methyl isobutyl ketone and acetic acid. It was dissolved in a mixed solvent of isobutyl at a weight ratio of 1: 1 to obtain a coating liquid for forming a primer layer.

Next, 720 parts by weight of water and 2-propanol 1
After mixing 080 parts by weight and 46 parts by weight of acetic acid, 480 parts by weight of γ-glycidoxypropyltrimethoxysilane (trade name “KBM403” manufactured by Shin-Etsu Chemical Co., Ltd.) and methyltrimethoxysilane (trade name manufactured by Shin-Etsu Chemical Co., Ltd.) "KBM1
3)) 240 parts by weight and 120 parts by weight of N-β (aminoethyl) γ-aminopropyltrimethoxysilane (trade name “KBM603” manufactured by Shin-Etsu Chemical Co., Ltd.) are sequentially mixed and stirred for 3 hours to mix the alkoxysilane. The solution was subjected to hydrolysis and partial condensation, and further diluted with a mixed solvent of isopropyl alcohol and 1-methoxy-2-propanol at a weight ratio of 1: 1 to obtain a coating solution for forming a protective layer.

Next, an ethyl alcohol dispersion of spherical silica fine particles having an average particle diameter of 160 nm (manufactured by Catalysis Chemical Co., Ltd.) was mixed with the above coating liquid for forming a protective layer so that the weight ratio of both solids was 1: 1. And then isopropyl alcohol and 1
The mixture was diluted with a mixed solvent of methoxy-2-propanol at a weight ratio of 1: 1 to obtain a coating liquid for forming a layer including fine particles and a binder.

A biaxially stretched polyethylene terephthalate (PET) film having a thickness of about 125 μm (OFW-
The above-mentioned coating liquid for forming a primer is roll-coated on both sides with a refractive index of about 125 and an in-plane refractive index of about 1.64 and a pencil hardness of F), and dried at 130 ° C. for 2 minutes to form a 0.8 μm-thick primer layer. Formed.

Subsequently, the coating liquid for forming a protective layer was roll-coated on the primer layer and dried at 130 ° C. for 10 minutes to form a protective layer having a thickness of about 5 μm and a refractive index of about 1.47.

Further, one of the surfaces of the film on which the protective layer was formed was roll-coated with a coating liquid for forming a layer comprising the fine particles and a binder, and dried at 130 ° C. for 5 minutes. Formed a layer in a state where a portion substantially corresponding to the hemisphere protruded on the surface.

Further, one surface of the film surface on which the protective layer is formed is roll-coated with a coating liquid for forming a layer comprising the above-mentioned fine particles and a binder, and dried at 130 ° C. for 5 minutes to form the fine particles and the binder. A layer was formed. When the surface and cross section of this layer were observed with a scanning electron microscope (SEM), fine irregularities were densely formed on the surface of the layer, the thickness of the layer was about 80 nm, and the height of the projections was about The range of about 50-80 nm, the length of the bottom of the protrusion was about 120-180 nm, and the average distance between the protrusions was about 200 nm. The pencil hardness of the surface of this layer was excellent at 2H, and the solvent resistance was also good.

Subsequently, a transparent conductive layer was formed by laminating a transparent conductive layer on the layer. As the transparent conductive layer, an indium-tin oxide (ITO) was used, and the layer was formed to have a thickness of about 22 nm by a DC magnetron sputtering method. That is, an ITO target having a composition of indium oxide and tin oxide in a weight ratio of 95: 5 and a packing density of 98% was used as a target, the film was set in a sputtering apparatus, and then exhausted to a pressure of 1.3 mPa. 98.5: 1 volume ratio of Ar to O2.
5 was introduced, and the atmospheric pressure was set to 0.27 Pa. Then, the film temperature is 50 ° C. and the input power density is 1 W
/ Cm ² , and a transparent conductive layer made of ITO was laminated on the layer made of the fine particles and the binder. The surface resistance of this transparent conductive layer is about 230Ω / □
And the refractive index was approximately 2.0.

The average reflectance of the surface of the laminate on which the transparent conductive layer was laminated was as low as about 4.5%, and the haze was 2.8%. In addition, the adhesion of the surface was as good as 100/100, and the steel wool abrasion test was good in B.

Example 2 1 part by weight of acetic acid, 30 parts by weight of water and 100 parts by weight of isopropanol were mixed, and 80 parts by weight of tetramethoxysilane (Shin-Etsu Chemical KBM04) and acryloxypropyltrimethoxysilane (Shin-Etsu Chemical) were mixed. After stirring at 240 ° C. for 15 minutes at 0 ° C. and then at 25 ° C. for 3 hours, hydrolysis and partial condensation of the alkoxysilane mixed solution were performed.

Further, 400 parts by weight of polyester acrylate (M8560 manufactured by Toa Gosei Chemical) and dipentaerythritol hexaacrylate (DPHA manufactured by Nippon Kayaku)
200 parts by weight, 50 parts by weight of a photoinitiator (Irgacure 184 manufactured by Ciba Geigy), 0.3 parts by weight of silicone oil (SH28PA manufactured by Dow Chemical Co., Ltd.) as a leveling agent, 1: 1 by weight of methoxy-2-propanol and isomalpropanol To obtain a coating liquid for forming a protective layer.

Roll coating of the protective layer forming coating solution was applied to both sides of a biaxially stretched polyethylene terephthalate film having a thickness of about 188 μm (OFW-188, manufactured by Teijin Limited, with an in-plane refractive index of about 1.65, pencil hardness F). Done, 60 ° C
After drying the solvent for 1 minute at a lamp intensity of 160 W /
cm using a high-pressure mercury lamp of about 600 mJ / cm
^The coating layer was cured by irradiating ultraviolet rays under the conditions of ² , and a protective layer having a thickness of about 5.2 μm and a refractive index of about 1.5 was laminated.

Subsequently, a layer composed of fine particles and a binder was formed on one surface of the film on which the protective layer was laminated, in exactly the same manner as in Example 1. The pencil hardness of this surface is 2H
And the solvent resistance was good.

Further, a transparent conductive layer was laminated on the layer in exactly the same manner as in Example 1 to form a transparent conductive laminate.
The average reflectance of the surface of the laminate on which the transparent conductive layer was laminated was as low as about 4.4%, and the haze was 2.8%. In addition, the adhesion of the surface was as good as 100/100, and the steel wool abrasion test was good in B.

Comparative Example 1 The procedure of Example 1 was repeated, except that the transparent conductive layer was laminated on the protective layer without laminating the layer composed of the fine particles and the binder. A laminate was made. The surface of the laminate on which the transparent conductive layer was laminated was substantially flat without any optically fine irregularities. The average reflectance of this surface is about 8.
The value was as high as 5%.

Comparative Example 2 The procedure of Example 2 was repeated, except that the transparent conductive layer was laminated on the protective layer without laminating the layer composed of the fine particles and the binder. A laminate was made. The average reflectance of the surface of the laminate on which the transparent conductive layer was laminated was a high value of about 8.2%.

Comparative Example 3 A transparent conductive laminate was produced in exactly the same manner as in Example 1 except that the following two layers were laminated as optical interference layers instead of the layer composed of fine particles and binder. It was created.

That is, first, tetrabutoxy titanate (trade name “B-4” manufactured by Nippon Soda Co., Ltd.) is converted into ligroin (a first-grade product manufactured by Wako Pure Chemical Industries) and butanol (a special grade manufactured by Wako Pure Chemical Industries) Roll coating was performed using a coating solution diluted with the mixed solvent of (Product) and heat-treated at 130 ° C. for 2 minutes to form a layer having a thickness of about 41 nm and a refractive index of about 1.82.

Next, the layer was roll-coated with a coating solution having the following composition and heat-treated at 130 ° C. for 5 minutes to form a layer having a thickness of about 51 nm and a refractive index of about 1.47. That is, 720 parts by weight of water and 2-propanol 108
After mixing 0 parts by weight and 46 parts by weight of acetic acid, 480 parts by weight of γ-glycidoxypropyltrimethoxysilane (trade name “KBM403” manufactured by Shin-Etsu Chemical Co., Ltd.) and methyltrimethoxysilane (trade name manufactured by Shin-Etsu Chemical Co., Ltd.) "KBM13") 2
40 parts by weight and N-β (aminoethyl) γ-aminopropyltrimethoxysilane (trade name “KBM manufactured by Shin-Etsu Chemical Co., Ltd.
603 ") 120 parts by weight are sequentially mixed and stirred for 3 hours to carry out hydrolysis and partial condensation of the alkoxysilane mixture, and further dilute with a mixed solvent of isopropyl alcohol and 1methoxy-2-propanol at a weight ratio of 1: 1. To form a coating liquid for forming the layer. The surface of this layer was flat without optically fine irregularities.

The average reflectance of the surface of the film on which the transparent conductive layer is laminated is as low as about 3.9%, and the haze value is also about 0.8%.
%. However, the result of the steel wool abrasion test was D, which was inferior to the example.

Comparative Example 4 The procedure of Example 2 was repeated, except that the two layers used in Comparative Example 3 were laminated as an optical interference layer instead of the layer composed of the fine particles and the binder. A conductive laminate was made. The average reflectance of the surface of the film on which the transparent conductive layer is laminated is about 4.1.
% And the haze was as low as 1.0%. However, the result of the steel wool abrasion test was E, which was inferior to the example.

[0101]

The transparent conductive laminate of the present invention has the characteristics that the reflectance and light scattering property of the surface of the transparent conductive layer are low, and the abrasion resistance of the transparent conductive layer is very excellent. In the case of a transparent tablet made using the laminate, very excellent visibility and mechanical durability can be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view of an example of a transparent conductive laminate of the present invention.

FIG. 2 is a schematic sectional view of an example of the transparent conductive laminate of the present invention.

FIG. 3 is a schematic sectional view of an example of the transparent conductive laminate of the present invention.

FIG. 4 is a schematic cross-sectional view of an example of the transparent conductive laminate of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Transparent conductive layer 2 Fine particle 3 Binder 4 Protective layer 5 Molded substrate of organic polymer 6 Layer composed of fine particle and binder a Height of convex part b Bottom part of convex part c Distance between convex parts d of layer composed of fine particle and binder thickness

Continued on the front page (72) Inventor Hitoshi Mikoshiba 4-3-2 Asahigaoka, Hino-shi, Tokyo Teijin Limited, Tokyo Research Center F-term (reference) 4F100 AA17C AA33C AK01A AK01B AK42 AK52B AK52D AR00D AT00 AT00A BA04 BA07 BA10C DE04A DE04B DE04C EH66 GB41 JB07 JB12B JG01 JG01C JN01 JN01C 5B087 AA09 AB16 AE00 CC14 CC16 CC36 5G307 FA02 FB01 FC01 FC08 FC10

Claims (13)

[Claims] 1. A transparent conductive laminate having a transparent conductive layer provided on the outermost surface of at least one surface of a substrate made of an organic polymer via a cured resin layer, if necessary, in contact with the transparent conductive layer. A transparent conductive laminate in which optically fine irregularities are densely formed on a surface of the substrate and / or the cured resin layer which is in contact with the transparent conductive layer, and has a wavelength of 450 to 450 on a surface on which the transparent conductive layer is provided. The average reflectance in the region of 650 nm is 5.5% or less, and the haze value is 1
A transparent conductive laminate having a content of 0% or less. 2. The transparent conductive laminate according to claim 1, wherein the height of the projections in the optically fine unevenness is 30 to 100 nm. 3. The transparent conductive laminate according to claim 1, wherein the average distance between the projections in the optically fine unevenness is 50 to 300 nm. 4. The transparent conductive laminate according to claim 1, wherein the bottom of the optically fine unevenness has a length of 50 to 200 nm. 5. The substrate according to claim 1, wherein the substrate and / or the cured resin layer in contact with the transparent conductive layer include fine particles having an average diameter of 50 to 300 nm. Transparent conductive laminate. 6. The transparent conductive laminate according to claim 1, wherein the cured resin layer in contact with the transparent conductive layer mainly comprises a condensate of silicon alkoxide. 7. The transparent conductive laminate according to claim 1, wherein the thickness of the transparent conductive layer is in the range of 12 to 30 nm. 8. The transparent conductive laminate according to claim 1, wherein the transparent conductive layer mainly comprises indium oxide. 9. A protective layer having solvent resistance and / or hard coat property is provided between a substrate made of an organic polymer and a cured resin layer.
The transparent conductive laminate according to any one of the above. 10. The protective layer according to claim 1, wherein the metal alkoxide and / or
10. The transparent conductive laminate according to claim 9, wherein the condensate is contained in a weight ratio of 20% or more. 11. The transparent conductive laminate according to claim 10, wherein the metal alkoxide is mainly composed of silicon alkoxide. 12. A transparent conductive laminate having a transparent conductive layer provided on the outermost surface on at least one surface of a substrate made of an organic polymer via a cured resin layer, in contact with the transparent conductive layer of the cured resin layer. Optically fine irregularities are densely formed on the surface, and the wavelength 45 on the surface provided with the transparent conductive layer is provided.
The average reflectance in the range of 0 to 650 nm is 5.5% or less, the haze value is 10% or less, and the cured resin layer is
A transparent conductive laminate mainly comprising a condensate of silicon alkoxide containing fine particles having an average diameter of 50 to 300 nm. 13. A transparent tablet in which two transparent electrode substrates are arranged with their electrode surfaces facing each other, wherein the transparent conductive laminate according to claim 1 is used as at least one of the transparent electrode substrates. Had a transparent tablet.