JP2008094064A - Heat-resistant acrylic resin laminate used for forming transparent conductive film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a transparent conductive laminate constituted by forming a transparent conductive film including tin-added indium oxide on a heat-resistant acrylic resin laminate having an inorganic barrier layer improved in surface hardness, optical characteristics and heat resistance by improving surface hardness by providing a hard coat layer and an inorganic barrier layer on a heat-resistant acrylic transparent resin substrate reduced in the change in double refraction caused by external force, that is, reduced in optical elastic modulus, that is, a transparent conductive laminate capable of used in a transparent electrode for display superior in optical characteristics, the stability of a resistance value and heat-resistance stability. <P>SOLUTION: The transparent conductive film is formed on the heat-resistant acrylic resin laminate, which is obtained by providing the hard coat layer and the inorganic barrier layer on a heat-resistant acrylic resin transparent substrate obtained by copolymerizing 40-90 mass% of a methyl methacrylate unit, 5-20 mass% of a maleic acid anhydride unit and 5-40 mass% of an aromatic vinyl compound to obtain the transparent conductive laminate superior in optical characteristics, the stability of the resistance value and heat-resistant stability. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The heat-resistant acrylic resin laminate of the present invention is suitable for forming a transparent conductive film, and the transparent conductive laminate excellent in optical characteristics, resistance value stability, and heat-resistant stability is used for photoelectric conversion of solar cells. Transparent electrodes such as element window electrodes, electromagnetic shielding films for electromagnetic shields, transparent electromagnetic wave absorbers, electrodes for input devices such as transparent touch panels, liquid crystal displays, EL (electroluminescence) emitters, EC (electrochromic) displays, etc. It is to provide a substrate such as.

  As a transparent resin, acrylic resins are characterized by their high light transmittance, weather resistance, and high rigidity compared to other transparent resins, and are used in lenses, automotive parts, lighting parts, various displays, etc. It is used in a wide range of applications such as appliances, building materials, signboards, paintings, display windows and nameplates of display devices. For the display window of a mobile phone, an acrylic resin sheet is widely used because it makes the internal liquid crystal display easy to see and at the same time protects the internal liquid crystal from external impacts and pressures and requires smoothness. When manufacturing and processing, those having a high surface hardness for scratch resistance, and acrylic resins are also required to have gas barrier properties because they absorb water.

  Further, the transparent conductive film is widely known as a film having both visible light transmittance and electrical conductivity, and a typical example thereof is a tin-added indium oxide film (hereinafter referred to as “ITO film”). A laminate in which an ITO film is laminated on a transparent substrate is widely used as an electrode, a heating element by energization, an electromagnetic wave shielding material, or a translucent body. Applications of the light transmitting body include automobiles, aircraft, building windows, screens, electromagnetic wave shielding plates such as monitors, liquid crystal display substrates, and the like. Examples of the shape of the translucent body include a planar shape and a curved surface shape according to the intended use. As means for forming an ITO film on a transparent substrate, a sputtering method, a vacuum deposition method, an ion plating method, and the like are known. As a base material for such a light transmitting body, glass has been mainly used so far. However, as demand and applications increase, improvement in workability and productivity has been demanded. Therefore, in recent years, plastics that are lighter than glass and superior in workability and productivity have attracted attention, and polyethylene terephthalate, polycarbonate, cyclic olefin resins, and the like have been used. A transparent conductive film in which a metal oxide gas / water vapor barrier layer is provided on a transparent plastic substrate is known (see, for example, Patent Document 1 and Patent Document 2).

For electrode substrates used in liquid crystal displays, a polymer material molded body having a smaller birefringence is required even if the total light transmittance is the same, and in recent years, the liquid crystal display has become larger in size and the polymer optical material necessary for it. In order to reduce the distribution of birefringence caused by the bias of external force as the molded product becomes larger, a material having a small change in birefringence due to external force, that is, a material having a small photoelastic coefficient is required. An electrode substrate in which a silicon oxide layer is provided on polyarylate or polycarbonate as a transparent optically isotropic base sheet is known (see, for example, Patent Document 3).
Among these, acrylic resins are widely used due to their high transparency. When used as a base material, acrylic resin base materials and ITO films are used to compensate for the lack of adhesion between the base material and the ITO film. It is known that a three-dimensionally cross-linked acrylic resin-based intermediate layer is interposed between them (see, for example, Patent Document 4 and Patent Document 5). However, the transparent conductive film substrate formed by forming the ITO film on the acrylic resin base material has not been put to practical use, due to poor adhesion between the base material and the ITO film, and destruction of the ITO film due to deformation of the base material. It is considered that the stability of the resistance value is not maintained.
: JP-A-55-105222 : JP 62-51740 A : Japanese Patent No. 3305022 : JP-A-62-71111 : JP 62-173248 A

  The present invention improves the surface hardness, optical properties, heat resistance by changing the birefringence due to external force, that is, having a hard coat layer and an inorganic barrier layer on a heat resistant acrylic transparent resin substrate having a small photoelastic coefficient. Heat-resistant acrylic resin laminate having a good inorganic barrier layer, and transparent conductive laminate in which a transparent conductive film including tin-added indium oxide is formed on this heat-resistant acrylic resin laminate, that is, optical characteristics An object of the present invention is to provide a transparent conductive laminate having excellent resistance value stability and heat resistance stability.

As a result of extensive research to solve these problems, 40 to 90% by mass of methyl methacrylate units, 5 to 20% by mass of maleic anhydride units, and 5 to 40% by mass of aromatic vinyl compound units were copolymerized. By forming a transparent conductive film on the heat-resistant acrylic resin laminate obtained by having a hard coat layer and an inorganic barrier layer on the heat-resistant acrylic resin transparent substrate obtained in this way, optical properties, stability of resistance value, heat resistance It discovered that the transparent conductive laminated body excellent in stability was made.
That is, the present invention is as follows.
(1) One side of a heat-resistant acrylic resin transparent substrate obtained by copolymerizing 40 to 90% by mass of methyl methacrylate units, 5 to 20% by mass of maleic anhydride units, and 5 to 40% by mass of aromatic vinyl compound units Alternatively, an indium oxide film containing at least one of tin, germanium, zinc, gallium, and magnesium is coated on at least one surface of the hard coat layer, which is characterized in that one or more hard coat treatments are performed on both sides. A heat-resistant acrylic resin laminate for forming a transparent conductive film.
(2) One side of a heat-resistant acrylic resin transparent substrate obtained by copolymerizing 40 to 90% by mass of methyl methacrylate units, 5 to 20% by mass of maleic anhydride units, and 5 to 40% by mass of aromatic vinyl compound units Or it has one or more kinds of inorganic barrier layers on both surfaces, and further comprises at least one surface of the transparent conductive film comprising an indium oxide film containing at least one of tin, germanium, zinc, gallium and magnesium. Heat-resistant acrylic resin laminate for film formation.
(3) On one or both surfaces of the heat resistant acrylic resin transparent substrate,
A. Hard coat layer B. (1) or a multilayer film formed of an inorganic barrier layer, and further comprising an indium oxide film containing at least one of tin, germanium, zinc, gallium, and magnesium on at least one surface thereof The heat resistant acrylic resin laminate for forming a transparent conductive film according to (2).
(4) On one or both surfaces of the acrylic resin transparent substrate,
A. First layer consisting of a hard coat layer. It has a multilayer film formed in the order of the second layer composed of an inorganic barrier layer, and further comprises an indium oxide film containing at least one of tin, germanium, zinc, gallium, and magnesium on at least one surface thereof. The heat-resistant acrylic resin laminate for forming a transparent conductive film as described in (3), which is characterized in that

(5) For forming a transparent conductive film according to any one of (2) to (4), wherein the inorganic barrier layer is a thin film of silicon oxide, silicon nitride, silicon oxynitride, or a mixed material composed of two or more thereof. Heat-resistant acrylic resin laminate.
(6) The heat-resistant acrylic resin laminate for forming a transparent conductive film according to (5), wherein the inorganic barrier layer is silicon oxide and is a film of SiOx (where 1 <x ≦ 2).
(7) The heat-resistant acrylic resin laminate for forming a transparent conductive film according to any one of (1) to (6), wherein the heat-resistant acrylic resin transparent substrate is a film or a sheet.
(8) Display of heat-resistant acrylic resin laminate for forming transparent conductive film according to (1) to (7), wherein total light transmittance is 70% or more and sheet resistance value is 100Ω / □ or less Use for transparent electrodes.
It is.

  The present invention is described in further detail below. In the heat-resistant acrylic resin of the acrylic resin transparent substrate in the present invention, methacrylic acid ester and / or acrylic acid ester, styrene and o-methylstyrene, p-methylstyrene, 2,4-dimethylstyrene, o-ethylstyrene, Aromatic vinyl compounds such as p-ethyl styrene, p-tert-butyl styrene, etc., nuclear alkyl-substituted styrene, α-methyl styrene, α-alkyl-substituted styrene such as α-methyl-p-methyl styrene, acrylonitrile, methacrylonitrile Copolymerization with vinyl cyanides such as N-phenylmaleimide and N-cyclohexylmaleimide, unsaturated carboxylic acid anhydrides such as maleic anhydride, and unsaturated acids such as acrylic acid, methacrylic acid and maleic acid. A polymer. Preferred is a methyl methacrylate-maleic anhydride-styrene copolymer. The copolymer contains 40 to 90% by weight of methyl methacrylate units, 5 to 20% by weight of maleic anhydride units, and 5 styrene units. From the viewpoint of heat resistance and photoelastic coefficient, it is preferable that the ratio of styrene units to maleic anhydride units is 1 to 3 times. More preferably, the methyl methacrylate unit in the copolymer is 42 to 83% by weight, the maleic anhydride unit is 5 to 18% by weight, and the styrene unit is 12 to 40% by weight, and particularly preferably in the copolymer. Of methyl methacrylate units of 45 to 78% by weight, maleic anhydride units of 6 to 15% by weight, and styrene units of 16 to 40% by weight. This resin has excellent heat resistance, moisture resistance, gas / water vapor barrier properties, optical properties, and solvent resistance.

  The heat-resistant acrylic resin preferably has a weight average molecular weight of 50,000 to 200,000. The weight average molecular weight is desirably 50,000 or more from the viewpoint of the strength of the molded product, and desirably 200,000 or less from the viewpoint of molding processability and fluidity. A more desirable range is 70,000 to 150,000. In the present invention, isotactic polymethacrylate and syndiotactic polymethacrylate can be used simultaneously. As a method for producing an acrylic resin, for example, generally used polymerization methods such as cast polymerization, bulk polymerization, suspension polymerization, solution polymerization, emulsion polymerization, and anionic polymerization can be used. It is preferable to avoid mixing of foreign substances as much as possible. From this viewpoint, bulk polymerization or solution polymerization without using a suspending agent or an emulsifier is desirable. When solution polymerization is performed, a solution prepared by dissolving a mixture of monomers in an aromatic hydrocarbon solvent such as toluene or ethylbenzene can be used. In the case of polymerization by bulk polymerization, the polymerization can be started by irradiation with free radicals generated by heating or ionizing radiation as is usually done.

  As the initiator used in the polymerization reaction, any initiator generally used in radical polymerization can be used. For example, an azo compound such as azobisisobutylnitrile, benzoyl peroxide, lauroyl peroxide, t-butylperoxy When an organic peroxide such as 2-ethylhexanoate is used and the polymerization is carried out particularly at a high temperature of 90 ° C. or higher, solution polymerization is common, so the 10-hour half-life temperature is 80 Peroxides and azobis initiators that are soluble in the organic solvent to be used are preferable, and specifically, 1,1-bis (t-butylperoxy) 3,3,5-trimethylcyclohexane, cyclohexane par. Oxide, 2,5-dimethyl-2,5-di (benzoylperoxy) hexane, 1,1-azobis (1-cyclohex Down-carbonitrile), and 2- (carbamoylazo) isobutyronitrile. These initiators are used in the range of 0.005 to 5% by mass. As the molecular weight regulator used as necessary for the polymerization reaction, any one used in general radical polymerization is used, for example, mercaptan compounds such as butyl mercaptan, octyl mercaptan, dodecyl mercaptan, 2-ethylhexyl thioglycolate, It is mentioned as preferable. These molecular weight regulators are added in a concentration range such that the degree of polymerization is controlled within the above range. As a method for producing the heat-resistant acrylic resin, the method described in JP-B-63-1964 can be used. Two or more kinds of acrylic resins having different molecular weights, compositions, etc. can be used at the same time.

  In order to produce the heat-resistant acrylic resin transparent substrate in the present invention, dyes, pigments, heat stabilizers such as hindered phenols and phosphates, benzotriazoles, 2-hydroxybenzophenones, phenyl salicylates as needed UV absorbers such as ester, plasticizers such as phthalate ester, fatty acid ester, trimellitic acid ester, phosphate ester, and polyester, higher fatty acid, higher fatty acid ester, higher fatty acid mono, di, or Mold release agents such as triglycerides, lubricants such as higher fatty acid esters and polyolefins, antistatic agents such as polyethers, polyether esters, polyether ester amides, alkyl sulfonates and alkylbenzene sulfonates, phosphorus Series, phosphorus / chlorine, phosphorus / bromine flame retardants, anti In order to prevent glare from irradiation, organic light diffusing agents such as methyl methacrylate / styrene copolymer beads, inorganic light diffusing agents such as barium sulfate, titanium oxide, calcium carbonate, talc, etc. Acrylic rubber obtained in (1) may be used. When these additives are blended, it can be carried out by a known method. For example, a method in which an additive is dissolved in a monomer mixture in advance and polymerized, or an additive is dry-blended with a mixer or the like in a molten state, bead-like or pellet-like resin, and kneaded and granulated using an extruder The method of doing is mentioned. However, it may be heat-treated at a high temperature when forming the transparent conductive film, and it is not preferable to add a volatile additive.

  As a hard-coat layer in this invention, what hardened the film which consists of a compound which has at least 2 functional group in a molecule | numerator is mentioned, for example. Examples of the functional group for forming the hard coat layer include a group having an unsaturated double bond such as a (meth) acryloyloxy group, and a reactive substituent such as an epoxy group or a silanol group. . Among these, a group having an unsaturated double bond is preferably used because it can be easily cured by irradiation with an activation energy ray such as an ultraviolet ray or an electron beam. Examples of the compound having at least two groups having an unsaturated double bond in the molecule include polyfunctional acrylate compounds. Here, the polyfunctional acrylate compound refers to a compound having at least two acryloyloxy groups and / or methacryloyloxy groups in the molecule. Hereinafter, the acryloyloxy group and the methacryloyloxy group are collectively referred to as a (meth) acryloyloxy group.

  Examples of the polyfunctional acrylate compound include the following. Ethylene glycol diacrylate, diethylene glycol diacrylate, 1,6-hexanediol diacrylate, neopentyl glycol diacrylate, trimethylolpropane triacrylate, trimethylolethane triacrylate, tetramethylolmethane triacrylate, tetramethylolmethane tetraacrylate, pentaglycerol Triacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, glycerin triacrylate, dipentaerythritol triacrylate, dipentaerythritol tetraacrylate, dipentaerythritol pentaacrylate, dipentaerythritol hexaacrylate, tris (acryloyloxyethyl) isocyanurate Ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, 1,6-hexanediol dimethacrylate, neopentyl glycol dimethacrylate, trimethylolpropane trimethacrylate, trimethylolethane trimethacrylate, tetramethylolmethane trimethacrylate, tetramethylolmethane tetramethacrylate, pentaglycerol Trimethacrylate, pentaerythritol trimethacrylate, pentaerythritol tetramethacrylate, glycerin trimethacrylate, dipentaerythritol trimethacrylate, dipentaerythritol tetramethacrylate, dipentaerythritol pentamethacrylate, dipentaerythritol hexamethacrylate, tris (acrylo (Luoxyethyl) isocyanurate, a phosphazene (meth) acrylate compound in which a (meth) acryloyloxy group is introduced into the phosphazene ring of the phosphazene compound, a polyisocyanate compound having at least two isocyanate groups in the molecule and at least one (meta ) A urethane (meth) acrylate compound obtained by reacting an acryloyloxy group and a polyol compound having at least one hydroxyl group, a carboxylic acid halide having at least two carbonyl groups in the molecule and at least one (meta ) A polyester (meth) acrylate compound obtained by reacting with a polyol compound having an acryloyloxy group.

These compounds can be used alone or in admixture of two or more. Further, oligomers such as dimers and trimers of these compounds may be used.
The hard coat layer can be provided by a usual method, for example, by applying a hard coat agent to the surface of the resin base material to form a coating film and irradiating it with an activation energy ray. Examples of the coating method include a micro gravure coating method, a roll coating method, a dipping coating method, a spin coating method, a die coating method, a flow coating method, and a spray coating method. The thickness of the hard coat layer is usually about 0.5 to 50 μm, preferably about 1 to 20 μm. More preferably, it is about 2-10 micrometers. When the thickness is not less than 0.5 μm and not more than 50 μm, the scratch resistance is good and cracks are less likely to occur.

  Such a hard coat layer may be an antistatic hard coat layer. Examples of the antistatic hard coat layer include a hard coat layer in which conductive particles are dispersed and a hard coat layer containing a surfactant. Examples of the hard coat layer in which conductive particles are dispersed include a layer in which conductive particles are dispersed in a cured coating obtained by curing a compound having at least two unsaturated double bonds. Examples of the conductive particles include oxides of metals such as tin, antimony, titanium, and indium, and composite oxides of these metals such as particles of indium tin composite oxide (ITO) and antimony-doped tin oxide. Can be mentioned. The particle diameter of the conductive particles is usually about 0.001 to 0.1 μm in terms of primary particle diameter. The particle diameter of the conductive particles is usually about 0.001 to 0.1 μm in terms of primary particle diameter. Within this range, transparency tends to be maintained.

In addition, inorganic fine particles may be contained in order to improve the abrasion resistance of the coating film and to reduce the volume shrinkage rate during curing. As the inorganic fine particles, fine particles made of a metal oxide such as silica and titanium oxide are preferable. The content of the inorganic fine particles is preferably 20 to 60% by weight, and the average particle size of the inorganic fine particles is preferably 100 μm or less. Within this content range, the curling of the product film can be suppressed, and the occurrence of cracks due to poor stretchability and bending of the hard coat resin can also be reduced. The average particle size is preferably 100 nm or more.
In order to improve the hard coat property (scratch prevention property) of the antireflection layer, it is preferable to introduce a photosensitive group having photopolymerization reactivity on the surface of the inorganic fine particles. This photosensitive group is preferably a monofunctional or polyfunctional acrylate.
The hard coat layer preferably has a pencil hardness of 4H or higher.

The inorganic barrier layer in the present invention not only enhances the surface hardness of the acrylic resin transparent substrate, but also improves transparency, adhesion to the transparent conductive film, improvement of durability of the acrylic resin transparent substrate, or gas / water vapor barrier. The effect of improving performance can be expected.
The inorganic barrier layer is preferably a thin film composed of a metal oxide, a metal nitride, or a mixture thereof. As a specific component of the inorganic barrier layer, in general, any material that can be vacuum-deposited can be used in principle. In particular, when a ceramic material is used, a highly transparent thin film can be formed. . Examples of the ceramic material include SiOx, AlOx, SiOxNy, SiNx, SiOxNyCz, SiNxCy, AlOxNy, AlNx, AlOxNyCz, and AlNxCy. Here, x, y, and z each represent a number. Among these metal compound materials, silicon oxide, silicon nitride, silicon oxynitride, and mixed materials thereof are preferable as the inorganic barrier layer. More preferably, it is a SiOx (where 1 <x ≦ 2) film, the surface hardness is hard, and it is non-conductive. Among these, the main component is silicon oxide having a ratio of the number of oxygen atoms to the number of silicon atoms of 1.5 to 2.0 in terms of gas barrier properties, transparency, surface smoothness, flexibility, film stress, cost, etc. Good metal oxide. The ratio of the number of oxygen atoms to the number of silicon atoms in the silicon oxide is analyzed and determined by X-ray photoelectron spectroscopy, X-ray microspectroscopy, Auger electron spectroscopy, Rutherford backscattering, and the like. When it is within this range, the transparency is good. Further, when the silicon oxide contains 5 to 30% by mass of magnesium oxide and / or magnesium fluoride with respect to the total weight, the transparency can be further increased.

The inorganic barrier layer can be formed by a vacuum film forming method such as an ion plating method, a sputtering method, a CVD (chemical vapor deposition) method, a plasma CVD method, or a physical vapor deposition method. Among these, from the viewpoint of obtaining an excellent gas barrier property on a resin substrate, an ion plating method capable of uniformly forming a large area by high-speed film formation is preferable.
As for the thickness of an inorganic barrier layer, 1-1000 nm is preferable, More preferably, it is 2-100 nm, More preferably, it is 3-50 nm.

  The film / sheet of the heat-resistant acrylic resin transparent substrate in the present invention is only a difference in thickness, the film is a thickness of 300 μm or less, and the sheet is more than 300 μm. The thickness of the heat-resistant acrylic transparent resin substrate is preferably a film or sheet in the range of 0.01 to 10.0 mm. A film or sheet in the range of 0.01 to 10.0 mm is hard to be deformed during panel processing and easy to handle. Further, since deformation due to the load on the substrate is less likely to occur, a double image becomes prominent when the liquid crystal display element is assembled, and the display quality is unlikely to be impaired. A more preferred thickness is in the range of 0.1 to 5.0 mm.

The film or sheet of the heat-resistant acrylic resin transparent substrate must have transparency, and as its transparency index, it is preferable that the total light transmittance is 80% or more and the haze value is 5% or less. More preferably, the total light transmittance is 85% or more and the haze value is 2% or less.
The film or sheet of the heat-resistant acrylic resin transparent substrate is preferably one having excellent optical isotropy, the retardation value is 30 nm or less, the variation of the slow axis is within 40 degrees, more preferably the retardation value is 20 nm or less, and the slow axis A variation within 20 degrees is preferred. Here, the retardation value is represented by a product Δn · d of a refractive index difference Δn of birefringence at a wavelength of 590 nm and a film thickness d measured using a known measuring apparatus.
The film or sheet of a heat-resistant acrylic resin transparent substrate must have heat resistance that can withstand the operating temperature when a metal vapor deposition film is formed on the surface by sputtering or vacuum vapor deposition. . As an index of the heat resistance, it is preferable that there is no warpage or deformation when left for about 30 minutes in an atmosphere at a temperature of 80 ° C.

As a material used for the transparent conductive film in the present invention, an indium oxide film containing at least one of tin, germanium, zinc, gallium, and magnesium can be used.
The content of tin, germanium, zinc, gallium, and magnesium added to the indium oxide film is the atomic ratio of these materials to indium (Sn / In, Ge / In, Zn) when one of these is added. / In, Ga / In, Mg / In) are all preferably 0.5 to 20.0%. More preferably, it is 5 to 10%. Of these, tin having the best balance between conductivity and transparency is most preferable. When added at such a ratio, the conductivity and transparency of the film can be maintained well. In addition, when a plurality of types of these materials are added, the total amount of materials to be added is preferably 20.0% or less with respect to indium.

The film thickness of the transparent conductive film is preferably set in the range of 10 nm to 1000 nm. In this film thickness range, although it varies depending on the application, it is possible to obtain a continuous film in which flexibility is maintained. Furthermore, the film thickness of the transparent conductive film of the present invention is desirably 20 to 500 nm depending on the application.
The transparent conductive laminate needs to have a total light transmittance of 70% or more and a haze value of 10% or less. In this range, the transparency is good. More preferably, the total light transmittance is 80% or more and the haze value is 5% or less. However, in the case of a transparent electrode for display, 70% or more can be applied.
Although the sheet resistance value of a transparent conductive laminated body changes with uses, the thing of the range of 5-10000 ohms / square is preferable as an electroconductive material. More preferably, the range of 10 to 300Ω / □ is preferable. However, those suitable for the transparent electrode for display are preferably in the range of 10 to 100Ω / □.
In the method for producing a transparent conductive laminate, the film forming method is not particularly limited, and a sputtering method, an EB vapor deposition method, an ion plating method, and a CVD method can also be used, but more preferably by a sputtering method. Form a film.

  The heat resistant acrylic resin laminate of the present invention is obtained by forming an ITO film on a multilayer laminate sheet having a hard coat layer and an inorganic barrier layer. The layer structure of the multilayer laminate may be any of a first layer: a hard coat layer, a second layer: an inorganic barrier layer, a first layer: an inorganic barrier layer, and a second layer: a hard coat layer on a transparent substrate. . Furthermore, you may have a layer structure in the single side | surface or both surfaces of a transparent substrate. Preferably, the transparent substrate has a first layer: hard coat layer and a second layer: inorganic barrier layer.

The hard coat layer contributes to imparting properties such as scratch resistance, surface hardness, moisture permeability resistance, heat resistance, and solvent resistance to the transparent substrate. The inorganic barrier layer contributes to imparting properties such as scratch resistance, surface hardness, moisture permeability resistance, gas resistance, heat resistance, and solvent resistance to the transparent substrate. Preferably, the combination of the hard coat layer constituting the first layer: the intermediate layer and the inorganic barrier layer constituting the second layer: the outermost layer serves to further improve the scratch resistance and surface hardness, and It is thought that damage due to heat is reduced during formation.
Furthermore, you may laminate | stack the layer of arbitrary resin or an inorganic compound 1 layer or 2 layers or more as an outermost layer in the zinc oxide type transparent conductive laminated body of this invention. Such an outermost layer can have a role of a protective film, an antireflection film, a filter, or the like, or functions such as adjustment of the viewing angle of liquid crystal and anti-fogging.

Hereinafter, the present invention will be described more specifically with reference to Examples and Comparative Examples. The unit displayed in parts represents parts by weight.
<Evaluation method>
(A) Evaluation of a resin laminate coated with a hard coat layer (A-1) Total light transmittance, haze Evaluation was performed according to JIS K 6711.
(A-2) Measurement of in-plane retardation (Re) In-plane retardation (Re) at 23 ° C. was measured by a rotating analyzer method using a birefringence measuring apparatus RETS-100 manufactured by Otsuka Electronics Co., Ltd.
(A-3) Appearance evaluation of hard coat layer In a room with a fluorescent lamp, the fluorescent lamp is reflected (reflected) on the surface of the resin laminate coated with the hard coat layer from above, and the display portion is viewed obliquely. When the image of the fluorescent lamp was distorted, the presence or absence of unevenness was visually observed, and when there was no unevenness, it was evaluated as “◯” (good), and when the unevenness occurred, it was evaluated as “x” (bad).
(A-4) Adhesiveness of durability test 1:
The resin laminate coated with the hard coat layer is allowed to stand in a thermostatic chamber at 80 ° C. for 24 hours, and the adhesive surface of the adhesive tape (1.8 cm wide cellophane tape made by Nichiban) is used as the adhesion evaluation method. Evaluation is made by a peel test in which the coat layer is brought into close contact with and peeled off. A case where the hard coat layer does not peel at all is indicated as “◯” (good), and a case where the hard coat layer is peeled off is indicated as “x” (defective).

(A-5) Measurement of photoelastic coefficient
A birefringence measuring apparatus described in detail in Macromolecules 2004, 37, 1062-1066 was used. A sheet piece tensioning device was placed in the laser beam path, and birefringence was measured while applying an extensional stress at 23 ° C. The strain rate during stretching was 20% / min (chuck interval: 30 mm, chuck moving speed: 6 mm / min), and the test piece width was 7 mm. From the relationship between birefringence (Δn) and tensile stress (σR), the photoelastic coefficient (CR) is calculated by finding the slope of the straight line in the linear region by least square approximation, and the absolute value (| CR |) of the optical inertia coefficient is obtained. It was. The smaller the absolute value of the slope is, the closer the photoelastic coefficient is to 0, indicating a preferable optical characteristic.
| CR | = | Δn | / σR
(CR: photoelastic coefficient, σR: stretching stress, Δn: birefringence, n1: refractive index in stretching direction, n
2: Refractive index perpendicular to the stretching direction)

(B) Evaluation of acrylic resin laminate having SiOx film (B-1) Total light transmittance, haze Measured in the same manner as (A-1) above.
(B-2) Measurement of in-plane retardation (Re) Measurement was performed in the same manner as in (A-2) above.
(B-3) State of SiOx film The surface of the acrylic resin laminate having the SiOx film was magnified 800 times with a microscope, and when no crack of the SiOx film was observed, it was evaluated as “◯” (good). Was evaluated as “x” (defect).
(B-4) Adhesion evaluation As an adhesion evaluation method, an adhesive tape (1.8 cm wide cellophane tape made of Nichiban) is adhered to the SiOx film of the transparent conductive laminate and evaluated by a peeling test. . The case where the SiOx film did not peel at all was indicated as “◯” (good), and the case where the entire surface was peeled off was indicated as “x” (defective).
(B-5) Measurement of photoelastic coefficient It measured similarly to said (A-5).

(C) Evaluation of a transparent conductive laminate formed by forming a transparent conductive film (C-1) Total light transmittance, haze Measured in the same manner as in the above (A-1).
(C-2) Measurement of in-plane retardation (Re) Measurement was performed in the same manner as in (A-2) above.
(C-3) Appearance evaluation of ITO film:
The surface of the transparent conductive laminate was magnified 800 times with a microscope, and when a crack of the ITO film was not observed, it was evaluated as “◯” (good), and when a crack was observed, it was evaluated as “×” (bad). .
(C-4) Adhesion evaluation As a method for evaluating adhesion, an adhesive tape (1.8 cm wide cellophane tape made of Nichiban) is adhered to the ITO film of the transparent conductive laminate and evaluated by a peeling test. . The case where the ITOO film did not peel at all was indicated as “◯” (good), and the case where the ITO film was peeled off was indicated as “x” (defective).

(C-5) Measurement of change in sheet resistance with time 4-probe method (contact type): Evaluated according to JIS R 1637.
The sheet resistance value of the transparent conductive laminate was measured with respect to what was left in the laboratory immediately after film formation and after 50 days.
(C-6) Durability test 1: Measurement of time-dependent change in sheet resistance after heat resistance test After standing at 80 ° C. in a thermostatic chamber for 200 hours, after returning to room temperature, the same method as in (B-5) is applied. Measured.
(C-7) Durability test 2: Measurement of time-dependent change in sheet resistance value after cold resistance test After leaving it to stand at −20 ° C. freezer for 200 hours and then returning to room temperature, the same method as in (B-5) It was measured.
(C-8) Durability test 3: Measurement of time-dependent change in sheet resistance value after wet heat resistance test After leaving at room temperature in a thermostatic chamber at 60 ° C. and 90% RH for 200 hours, after returning to room temperature (B-5) It measured by the same method.

(C-9) Deformation Evaluation of Substrate 1: Thermal Oven Test The substrate was left to stand for about 30 minutes in an atmosphere at a temperature of 80 ° C., and the warpage and deformation were evaluated visually. When the transparent conductive laminate is not deformed or warped at all, “◯” (good), when it is slightly deformed / warped, “△” (possible), and when deformed / warped, “×”. (Bad) is displayed.
(C-10) Deformation Evaluation 2 of Substrate 2: Thermal Oven Test The substrate was left to stand for about 1 hour in an atmosphere at a temperature of 90 ° C., and the warpage and deformation were evaluated visually. When the transparent conductive laminate is not deformed or warped at all, “◯” (good), when it is slightly deformed / warped, “△” (possible), and when deformed / warped, “×”. (Bad) is displayed.

<Raw materials used>
(A) Acrylic resin 1,1-di-t-butylperoxy-3 was added to a monomer mixture consisting of 96.7 parts by weight of methyl methacrylate, 2.1 parts by weight of methyl acrylate, and 1 part by weight of xylene. , 3,3-trimethylcyclohexane 0.0294 parts by weight and n-octyl mercaptan 0.28 parts by weight are added and mixed uniformly. This solution is continuously supplied to a closed pressure-resistant reactor having an internal volume of 10 liters, polymerized with stirring at an average temperature of 130 ° C. and an average residence time of 2 hours, and then continuously sent to a reservoir connected to the reactor. The volatile matter is removed under a certain condition, and further transferred to the extruder in a molten state. The acrylic resin (methyl methacrylate / methyl acrylate) copolymer pellets used in the following examples Obtained. The resulting copolymer had a methyl acrylate content of 2.0%, a weight average molecular weight of 102,000, and a melt flow rate value of 230 g at a load of 3.8 kg measured in accordance with ASTM-D1238 was 2.0 g. / 10 minutes.

(B) Heat-resistant acrylic resin A methyl methacrylate-maleic anhydride-styrene copolymer was obtained by the method described in JP-B 63-1964. The composition of the obtained copolymer was methyl methacrylate 74% by mass, maleic anhydride 10% by mass, styrene 16% by mass, copolymer melt flow rate value (ASTM-D1238; 230 ° C., 3.8 kg load). ) Was 1.6 g / 10 min.
(C) Preparation of each resin transparent substrate A flat plate (80 × 80 × 2 mmt) was prepared for each resin using an F40 injection molding machine manufactured by Crockner. The molding temperature of each resin was as follows: acrylic resin: 260 ° C., heat-resistant acrylic resin: 270 ° C., polycarbonate resin: 300 ° C.

[Example 1 and Comparative Example 1]
(B) Commercially available JPC hard coats for resin transparent substrate sheets (80 × 80 × 2 mmt) obtained by injection-molding each of heat-resistant acrylic resin and polycarbonate resin (product name WONDERLITE PC175 manufactured by Asahi Kasei Co., Ltd.) Each sheet was immersed in liquid TKH-36A, pulled up, and irradiated with ultraviolet rays to form a hard coat layer on the sheet surface. The thickness of each hard coat layer was adjusted to about 5 μm. The evaluation results of each resin laminate are also shown in Table 1.

[Example 2 and Comparative Example 2]
A SiOx (where 1 <x ≦ 2) film was further formed by sputtering on each of the resin laminates on which the hard coat layers of Example 1 and Comparative Example 1 were formed. The thickness of the SiOx film was adjusted to about 30 nm.
The evaluation results of the acrylic resin laminate are also shown in Table 2.

[Example 3 and Comparative Examples 3 and 4]
On the sheet of each resin laminate on which the hard coat layer of Example 1 and Comparative Example 1 was formed and (a) an acrylic resin sheet, ITO was formed as a transparent conductive film by a DC magnetron sputtering method, and transparent conductive A laminate was obtained. The film thickness of the transparent conductive film was adjusted to about 400 nm. In this sputtering, In ₂ O ₃ / SnO ₂ with a mass ratio of 90/10 is used as a target, exhausted to 10 ⁻³ Pa, argon / oxygen with a volume ratio of 92.5 / 7.5 is used as an introduction gas, DC magnetron sputtering was performed at room temperature. The film formation time was about 10 minutes. The evaluation results of the transparent conductive laminate are also shown in Table 3.

[Example 4]
On the sheet | seat of each resin laminated body obtained in Example 1, ITO was formed into a film as a transparent conductive film by DC magnetron sputtering method, and the transparent conductive laminated body was obtained. The film thickness of the transparent conductive film was adjusted to about 1200 nm. In this sputtering, In ₂ O ₃ / SnO ₂ with a mass ratio of 90/10 is used as a target, exhausted to 10 ⁻³ Pa, argon / oxygen with a volume ratio of 92.5 / 7.5 is used as an introduction gas, DC magnetron sputtering was performed at room temperature. The film formation time was about 30 minutes.
The transparent conductive laminate formed into a heat-resistant acrylic resin laminate had a total light transmittance of 83.5% and a sheet resistance value of about 55Ω / □.

[Example 5 and Comparative Example 5]
On the sheet of each resin laminate obtained in Example 2 and Comparative Example 2, ITO was formed as a transparent conductive film by a DC magnetron sputtering method to obtain a transparent conductive laminate. The film thickness of the transparent conductive film was adjusted to about 400 nm. In this sputtering, In ₂ O ₃ / SnO ₂ with a mass ratio of 90/10 is used as a target, exhausted to 10 ⁻³ Pa, argon / oxygen with a volume ratio of 92.5 / 7.5 is used as an introduction gas, DC magnetron sputtering was performed at room temperature. The film formation time was about 10 minutes. The evaluation results of the transparent conductive laminate are also shown in Table 4.

  The heat-resistant acrylic resin laminate of the present invention has very good surface hardness, and a transparent conductive laminate having a transparent conductive film, that is, a transparent conductive laminate excellent in optical properties and heat resistance is Battery photoelectric conversion element window electrode, electromagnetic shielding electromagnetic shielding film, transparent electromagnetic wave absorber, electrode of input device such as transparent touch panel, liquid crystal display, EL (electroluminescence) illuminant, EC (electrochromic) display It is possible to provide a substrate such as a transparent electrode.

Claims (8)

  On one or both sides of a heat-resistant acrylic resin transparent substrate obtained by copolymerizing 40 to 90% by mass of methyl methacrylate units, 5 to 20% by mass of maleic anhydride units and 5 to 40% by mass of aromatic vinyl compound units A transparent conductive film comprising an indium oxide film containing at least one of tin, germanium, zinc, gallium, and magnesium on at least one surface thereof, wherein the hard coat layer is coated with at least one hard coat treatment. Heat-resistant acrylic resin laminate for film formation.   On one or both sides of a heat-resistant acrylic resin transparent substrate obtained by copolymerizing 40 to 90% by mass of methyl methacrylate units, 5 to 20% by mass of maleic anhydride units and 5 to 40% by mass of aromatic vinyl compound units For forming a transparent conductive film comprising an indium oxide film containing at least one of tin, germanium, zinc, gallium and magnesium on at least one surface thereof, characterized by having at least one inorganic barrier layer Heat-resistant acrylic resin laminate. On one or both surfaces of the heat-resistant acrylic resin transparent substrate,
A. Hard coat layer B. 2. A multilayer film formed of an inorganic barrier layer, and further comprising an indium oxide film containing at least one of tin, germanium, zinc, gallium, and magnesium on at least one surface thereof. 2. A heat-resistant acrylic resin laminate for forming a transparent conductive film according to 2. On one or both surfaces of the acrylic resin transparent substrate,
A. First layer consisting of a hard coat layer. It has a multilayer film formed in the order of the second layer composed of an inorganic barrier layer, and further comprises an indium oxide film containing at least one of tin, germanium, zinc, gallium, and magnesium on at least one surface thereof. The heat-resistant acrylic resin laminate for forming a transparent conductive film according to claim 3.   The heat-resistant acrylic for forming a transparent conductive film according to any one of claims 2 to 4, wherein the inorganic barrier layer is a thin film of silicon oxide, silicon nitride, silicon oxynitride, or a mixed material composed of two or more thereof. -Based resin laminate.   The heat-resistant acrylic resin laminate for forming a transparent conductive film according to claim 5, wherein the inorganic barrier layer is silicon oxide and is a film of SiOx (where 1 <x ≦ 2).   The heat-resistant acrylic resin laminate for forming a transparent conductive film according to any one of claims 1 to 6, wherein the heat-resistant acrylic resin transparent substrate is a film or a sheet.   The transparent electrode for display of a heat-resistant acrylic resin laminate for forming a transparent conductive film according to claim 1, wherein the total light transmittance is 70% or more and a sheet resistance value is 100Ω / □ or less. Use for.