JP5906774B2 - Laminated body - Google Patents

Description

  The present invention exhibits excellent transparency and water vapor barrier properties when used as a substrate for electronic materials such as electronic paper, solar cells, and organic EL, and improves the temporal reliability of the device during long-term use. It relates to a laminate.

  In recent years, display devices such as electronic paper and organic EL, and energy devices such as solar cells are rapidly spreading. Conventionally, glass substrates have been used for these applications, but from the viewpoints of weight reduction, difficulty in cracking, and flexibility, there is an increasing demand for replacing glass substrates with transparent plastic films.

  However, when the glass substrate is replaced with a transparent plastic film, the water is transmitted through the transparent plastic film, so that the device is deteriorated. In order to solve this problem, it is conceivable to use a gas barrier film in which an inorganic thin film layer that is transparent and has a gas barrier property is laminated on a substrate made of a transparent plastic film. Such gas barrier films have been widely used mainly for food packaging applications. However, gas barrier films used in conventional food packaging applications have insufficient moisture barrier properties, and it has been difficult to suppress device degradation.

Therefore, for use in display devices such as electronic paper and organic EL, and energy devices such as solar cells, the water vapor permeability with a cured resin layer and a metal oxide layer provided on at least one side of the polymer film is high. A gas barrier film of less than 0.1 g / m ² / day has been proposed (Patent Document 1). However, a gas barrier film having a metal oxide layer, which is an inorganic thin film layer as described in Patent Document 1, is exposed to the surface, but is excellent in gas barrier properties as a film. There is a problem that it is easy to occur and it is difficult to obtain a sufficient gas barrier property.

  On the other hand, other biaxial stretching is performed on the surface of the moisture-proof layer produced on the biaxially stretched polyester film for the purpose of sufficiently exhibiting gas barrier properties without causing cracks even when incorporated in a device. A gas barrier support having a polyester film bonded thereto has been proposed (Patent Document 2). However, although this gas barrier support is used as a display support, transparency is not considered at all. In addition, Patent Document 2 does not show a specific mode.

JP 2006-281505 A Japanese Patent No. 4106667

  This invention is made | formed in view of the problem of this prior art, The objective is to provide the laminated body which was excellent in transparency and excellent in water vapor | steam barrier property.

The laminate of the present invention that has solved the above problems has the following configuration.
(1) A laminate in which a second transparent plastic film is laminated on an inorganic thin film layer side of a laminated film in which an inorganic thin film layer made of an inorganic material is laminated on one side of the first transparent plastic film. The refractive index n _{1 of} the first transparent plastic film, the refractive index n ₂ of the pressure-sensitive adhesive layer, and the refractive index n ₃ of the inorganic thin film layer satisfy the following relationships (i) and (ii): A laminate characterized by the following.
| N ₃ −n ₁ | ≦ 0.2 (i)
| N ₃ −n ₂ | ≦ 0.2 (ii)
(2) The laminate according to (1), wherein the inorganic thin film layer has a thickness of 10 to 200 nm.
(3) The laminate according to (1) or (2), wherein the inorganic thin film layer contains Al ₂ O ₃ .
(4) The laminate according to any one of (1) to (3), wherein the inorganic thin film layer is formed by an impedance control method using a reactive sputtering method.
(5) The laminate according to any one of the said refractive index n ₄ of the second transparent plastic film and the refractive index n ₃ of the inorganic thin film layer satisfies the following relationship (iii) (1) ~ (4) .
| N ₃ −n ₄ | ≦ 0.2 (iii)
(6) The laminate according to any one of (1) to (5), wherein a transparent conductive thin film layer is provided on a surface opposite to the surface on which the adhesive layer of the second transparent plastic film is provided. .
(7) The laminate according to any one of (1) to (6), wherein a hard coat layer is provided on a surface opposite to the surface on which the inorganic thin film layer of the first transparent plastic film is provided.
(8) The laminate according to (7), wherein the hard coat layer is antiglare treated.

  ADVANTAGE OF THE INVENTION According to this invention, the laminated body which has the outstanding transparency and the outstanding water vapor | steam barrier property can be provided. And when this laminated body is used as a board | substrate of electronic materials, such as electronic paper, a solar cell, and organic EL, the effect that the temporal reliability of the device at the time of long-term use can be improved is acquired.

FIG. 1 is a schematic cross-sectional view showing an embodiment of the laminate of the present invention. FIG. 2 is a schematic cross-sectional view showing another embodiment (laminate with transparent conductive thin film) of the laminate of the present invention.

In the laminate of the present invention, the second transparent plastic film is placed on one side of the first transparent plastic film on the inorganic thin film layer side of the laminated film obtained by laminating the inorganic thin film layer made of an inorganic material via the adhesive layer. It is a laminated body.
One embodiment of the laminate of the present invention is shown in FIGS. In the laminated body 10 shown in FIG. 1, the 1st transparent plastic film 1 is used as a base material, the inorganic thin film layer 3, the adhesive layer 4, and the 2nd transparent plastic film 5 are laminated | stacked in order on the one side, and also 1st A cured product layer 2 is provided on the other surface of the transparent plastic film 1. Moreover, in the laminated body 11 with a transparent conductive thin film shown in FIG. 2, the transparent conductive thin film layer 6 is further laminated | stacked on the 2nd transparent plastic film 5 in the laminated body 10 shown in FIG.

In the present invention, the refractive index n _{1 of} the first transparent plastic film, the refractive index n ₂ of the pressure-sensitive adhesive layer, and the refractive index n ₃ of the inorganic thin film layer satisfy the following relationships (i) and (ii): This is very important.
| N ₃ −n ₁ | ≦ 0.2 (i)
| N ₃ −n ₂ | ≦ 0.2 (ii)
If it is a laminated body satisfying both of the relationships (i) and (ii), it becomes a laminated body having excellent transparency and water vapor barrier properties. The value of | n ₃ −n ₁ | is preferably 0.16 or less, more preferably 0.09 or less, and the value of | n ₃ −n ₂ | is preferably 0.16 or less, more preferably 0.09 or less. The refractive index n ₁ of the first transparent plastic _film, the refractive index n ₃ of the refractive index n ₂ and the inorganic thin film layer of the pressure-sensitive adhesive layer, respectively, can be measured by the method described later in Examples.

Further, in the present invention, the refractive index n ₄ of the second transparent plastic film and the refractive index n ₃ of the inorganic thin film layer preferably satisfies the following relationship (iii).
| N ₃ −n ₄ | ≦ 0.2 (iii)
If the laminate satisfies the relationship (iii) above, more excellent transparency and water vapor barrier properties are exhibited. The value of | n ₃ −n ₄ | is preferably 0.16 or less, more preferably 0.09 or less. The refractive index n ₄ of the second transparent plastic film may be measured by a method described later in Examples.

  In order to satisfy the relationship (i) and (ii) above, and further the relationship (iii) above, the refractive index of each film or each layer (material forming the layer) constituting the laminate of the present invention is set. Adjust it.

Hereafter, each film and layer which comprise the laminated body of this invention are demonstrated.
(First and second transparent plastic films)
The first and second transparent plastic films are formed into a film by melt extrusion or solution extrusion of an organic polymer into a film, and if necessary, stretched, heated in one or both of the longitudinal direction and the width direction. A film that has been fixed and heat-relaxed.

  Organic polymers include polyethylene, polypropylene, polyethylene terephthalate, polyethylene-2,6-naphthalate, polypropylene terephthalate, nylon 6, nylon 4, nylon 66, nylon 12, polyimide, polyamideimide, polyethersulfane, polyetheretherketone , Polycarbonate, polyarylate, cellulose propionate, polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, polyetherimide, polyphenylene sulfide, polyphenylene oxide, polystyrene, syndiotactic polystyrene, norbornene polymers (cycloolefin polymers, etc.), etc. Is mentioned. Among these, polyethylene terephthalate, polypropylene terephthalate, polyethylene-2,6-naphthalate, polycarbonate, polyarylate, syndiotactic polystyrene having a low water absorption, and cycloolefin polymer of norbornene polymer are preferable. In addition, these organic polymers may be obtained by copolymerizing a small amount of monomer components of other organic polymers, or a plurality of organic polymers may be blended.

  The first and second transparent plastic films may be a single-layer film made of one kind of plastic, or may be a laminated film in which two or more kinds of plastic films are laminated. There are no particular limitations on the type of laminate, the number of laminations, the lamination method, and the like in the case of a laminated film, and any one of known methods can be selected according to the purpose.

  The thicknesses of the first and second transparent plastic films are each preferably 10 μm or more, and more preferably 20 μm or more. If the thickness of the transparent plastic film is less than 10 μm, the mechanical strength is insufficient, and handling in a device manufacturing process such as electronic paper may be difficult. Moreover, it is preferable that the thickness of the 1st and 2nd transparent plastic film is 200 micrometers or less, More preferably, it is 160 micrometers or less. When the thickness of the transparent plastic film exceeds 200 μm, the thickness of a device such as electronic paper becomes too thick, which may not be suitable.

  Surface activation treatments such as corona discharge treatment, glow discharge treatment, flame treatment, ultraviolet irradiation treatment, electron beam irradiation treatment, ozone treatment, etc. are applied to the first and second transparent plastic films within a range not impairing the object of the present invention. May be applied.

(Hard coat layer (hardened product layer))
The first transparent plastic film may be provided with one or more hardened material layers mainly composed of a curable resin on both sides or one side. Providing a cured product layer on the surface of the first transparent plastic film on which the inorganic thin film layer is formed has the effect of improving adhesion to the inorganic thin film layer, imparting chemical resistance, and preventing precipitation of low molecular weight substances such as oligomers. can get. Further, when a cured product layer is provided on the surface of the first transparent plastic film opposite to the surface on which the inorganic thin film layer is formed, effects such as imparting chemical resistance and preventing precipitation of low molecular weight materials such as oligomers can be obtained. In this specification, the hardened | cured material layer provided in the surface on the opposite side to the inorganic thin film layer formation surface of a 1st transparent plastic film may be especially called a "hard-coat layer."

  The curable resin is not particularly limited as long as it is a resin that is cured by energy application such as heating, ultraviolet irradiation, electron beam irradiation, etc., silicone resin, acrylic resin, methacrylic resin, epoxy resin, melamine resin, polyester resin, urethane resin Etc. From the viewpoint of productivity, a curable resin containing an ultraviolet curable resin as a main component is preferable.

  Examples of the ultraviolet curable resins include polyfunctional acrylate resins such as polyhydric alcohol acrylic esters or methacrylic esters; diisocyanates and polyhydric alcohols, and hydroxyalkyl esters of acrylic acid or methacrylic acid. Examples of the multifunctional resin include a multifunctional urethane acrylate resin as synthesized. These polyfunctional resins may be those obtained by copolymerizing a monofunctional monomer (for example, vinyl pyrrolidone, methyl methacrylate, styrene, etc.) as necessary.

  The ultraviolet curable resin is usually used by adding a photopolymerization initiator. As the photopolymerization initiator, known compounds that absorb ultraviolet rays and generate radicals can be used without particular limitation, and examples thereof include various benzoins, phenyl ketones, and benzophenones. Usually, the addition amount of the photopolymerization initiator is preferably about 1 to 5 parts by mass with respect to 100 parts by mass of the ultraviolet curable resin.

In order to provide the cured product layer, for example, after coating the coating liquid containing the curable resin on the first transparent plastic film, if necessary, it is heated and dried, or an ultraviolet curable resin is used. May be irradiated with ultraviolet rays. The coating method is not particularly limited, and a known method such as a bar coating method, a gravure coating method, or a reverse coating method can be employed. The heating temperature is not particularly limited as long as it is appropriately set according to the boiling point of the solvent used in the coating solution, but is usually preferably 50 ° C. or higher and 250 ° C. or lower, more preferably 70 ° C. or higher and 200 ° C. or lower. In addition, the amount of light at the time of ultraviolet irradiation is usually preferably from 100 mJ / cm ^{2 to} 500 mJ / cm ² , more preferably from 200 mJ / cm ^{2 to} 400 mJ / cm ² .

  What is necessary is just to select the density | concentration of the coating liquid containing the said curable resin suitably considering the viscosity etc. according to the coating method. For example, when the coating solution contains an ultraviolet curable resin and a photopolymerization initiator, the proportion of the total amount of the ultraviolet curable resin and the photopolymerization initiator in the coating solution is usually about 20 to 80% by mass. .

  In addition, you may add well-known additives, such as leveling agents, such as a silicone type surfactant and a fluorochemical surfactant, to a coating liquid as needed.

  The thickness of the cured product layer is preferably 0.1 μm or more, more preferably 0.5 μm or more, and particularly preferably 1 μm or more. When the thickness of the cured product layer is less than 0.1 μm, it becomes difficult to form a sufficiently cross-linked structure, making it difficult to obtain chemical resistance and insufficient suppression of low molecular weight substances such as oligomers. There is a tendency that the effect of improving the adhesion cannot be obtained. Moreover, it is preferable that the thickness of a hardened | cured material layer is 15 micrometers or less, More preferably, it is 10 micrometers or less, Most preferably, it is 8 micrometers or less. When the thickness of the cured product layer exceeds 15 μm, productivity tends to decrease.

  The cured product layer (that is, the hard coat layer) provided on the surface of the first transparent plastic film opposite to the surface on which the inorganic thin film layer is formed is preferably antiglare treated. When the antiglare treatment is applied to the hard coat layer that is the outermost surface of the laminate, it can be suitably used for display display devices such as electronic paper and organic EL. The anti-glare treatment can be performed, for example, by adding silica particles to a coating solution that forms a cured product layer.

  The cured product layer is preferably subjected to a surface treatment in order to improve adhesion to the inorganic thin film layer. Specific methods include a discharge treatment method that irradiates glow discharge or corona discharge, a method of increasing carbonyl group, carboxyl group, hydroxyl group, a chemical treatment method of treating with acid or alkali, and an amino group. And a method of increasing polar groups such as a hydroxyl group and a carbonyl group.

(Inorganic thin film layer)
The inorganic thin film layer is a thin film made of a metal or an inorganic oxide. As a material for forming the inorganic thin film layer, a metal oxide such as SiO _2, Al ₂ O _3, complex metal oxides such as SiO ₂ -Al ₂ O ₃ and the like. Among these, a material containing Al ₂ O ₃ is preferable in terms of water vapor barrier properties.

Refractive index _{n 3} of the inorganic thin film layer is preferably 1.45 or more, more preferably 1.50 or more. If the refractive index n ₃ is less than 1.45, and is easy to become a porous film tends to be difficult to improve gas barrier properties. The refractive index _{n 3} of the inorganic thin film layer is preferably 1.70 or less, more preferably 1.65 or less. If the refractive index n ₃ is greater than 1.70, the first or second transparent plastic film, the refractive index difference between the adhesive layer is increased, the transmittance of the laminate may deteriorate.

  The film thickness of the inorganic thin film layer is preferably 10 nm or more, more preferably 20 nm or more, and further preferably 30 nm or more. When the film thickness of an inorganic thin film layer is less than 10 nm, it becomes difficult to become a continuous thin film and it becomes difficult to obtain favorable gas barrier properties. The thickness of the inorganic thin film layer is preferably 200 nm or less, more preferably 180 nm or less, and still more preferably 160 nm or less. When the film thickness of the inorganic thin film layer exceeds 200 nm, the stress of the inorganic thin film layer increases, and when the first transparent plastic film is thin, cracks are likely to occur, and the water vapor barrier property may be deteriorated. Further, when the film thickness is increased, the water vapor barrier property is improved, but when the layer is laminated exceeding 100 nm, the productivity is lowered. Therefore, the most preferable range is 30 to 100 nm.

  As a method for forming an inorganic thin film layer, a vacuum deposition method, a sputtering method, a CVD method, an ion plating method, a spray method, and the like are known. Among these known methods, depending on the film thickness to be formed. And can be selected as appropriate. In particular, the sputtering method is preferable from the viewpoint of reducing the variation in film thickness. In general, when a film is formed by a sputtering method, a reactive DC or AC sputtering method is used. In this reactive sputtering method, in order to improve the deposition rate, an impedance control method for controlling the reactive gas flow rate so as to keep the voltage value of the DC or AC power source constant, or in a plasma of a specific element. A plasma emission method in which the flow rate of the reactive gas is controlled so as to keep the emission intensity constant is preferable. In particular, the impedance control method is preferable because it does not become large in terms of equipment and is excellent in process stability.

In the impedance control method, the discharge voltage in the metal mode when only an inert gas such as Ar is flowed is 100%, and the oxide or nitride mode when a reactive gas such as O ₂ and N ₂ is flowed is used. When the discharge voltage is 0%, the discharge voltage is preferably controlled to a value of 20 to 80%, particularly preferably 30 to 70%. If it is lower than 20%, the effect of improving the film formation rate tends to be small. On the other hand, if it exceeds 80%, the film thickness distribution in the film width direction tends to occur.

  When forming the inorganic thin film layer, means such as ozone addition, plasma irradiation, and ion assist may be used in combination. In addition, a bias such as direct current, alternating current, and high frequency may be applied to the substrate as long as the object of the present invention is not impaired.

Moreover, as a water pressure at the time of forming an inorganic thin film layer, 2 * 10 < ^-3 > Pa or less is preferable, More preferably, it is 5 * 10 <^-4> Pa or less. When the water pressure exceeds 2 × 10 ⁻³ Pa, hydrogen is taken into the inorganic thin film layer, and the growth of the network (for example, M—O—) may stop. Therefore, the continuity of the inorganic thin film layer The gas barrier properties may be reduced.

  When forming the inorganic thin film layer, the first transparent plastic film can be previously exposed to vacuum. At this time, the pressure is usually about 0.001 Pa or more and 0.01 Pa or less, and the exposure time is usually 5 minutes or more.

  When forming an inorganic thin film layer, an optical characteristic (transmittance, color) measuring device is provided in the film forming apparatus in order to stably obtain an inorganic thin film layer having excellent gas barrier properties. preferable. The film thickness and oxidation degree of the inorganic thin film layer can be confirmed by measuring the optical characteristics. It is also effective to perform in-line measurement using fluorescent X-rays for film thickness measurement.

(Adhesive layer)
When the second transparent plastic film is laminated on the inorganic thin film layer of the above-described laminated film, the pressure-sensitive adhesive layer is coated with an adhesive resin on at least one of the inorganic thin film layer and the second transparent plastic film, Is formed by laminating a sheet.

  The adhesive resin is not particularly limited, and for example, a known resin such as an acrylic resin, a silicon resin, or a rubber resin can be used. In particular, an acrylic resin suitable for optical use is preferable.

  The acrylic resin can be obtained, for example, by polymerizing a monomer component containing (meth) acrylic acid alkyl ester. Examples of (meth) acrylic acid alkyl esters include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, n-butyl (meth) acrylate, iso-butyl (meth) acrylate, and t-butyl (meth). Examples include acrylate, n-hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-octyl (meth) acrylate, iso-octyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, and the like.

  The monomer component containing the (meth) acrylic acid alkyl ester can be further copolymerized with a monomer having a hydrophilic group such as a hydroxyl group, a carboxyl group, an amide group, or an amino group. By copolymerizing a monomer having a hydrophilic group, adhesion to an adherend can be increased. Specifically, acrylic acid, methacrylic acid, maleic anhydride, styrene having a carboxyl group, 2-hydroxylethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, acrylamide, methacrylamide, dimethylaminoethyl (meth) An acrylate etc. are mentioned.

  When obtaining the acrylic resin, usually, a polymerization initiator for accelerating the polymerization reaction is added to sequentially polymerize the monomer components. And the obtained acrylic resin is used in the state containing the unreacted polymerization initiator which remained after completion | finish of polymerization reaction. However, unreacted polymerization initiators affect the barrier properties and may reduce environmental stability such as heat and humidity resistance. Therefore, it is desirable to reduce the unreacted amount of the polymerization initiator as much as possible during the polymerization. Specifically, the amount of the unreacted polymerization initiator contained in the acrylic resin is 0.2% by mass or less. Is preferable, more preferably 0.1% by mass or less, and still more preferably 0.05% by mass or less. The unreacted amount of the polymerization initiator can be controlled by the polymerization time, the polymerization temperature, the addition amount of the polymerization initiator, and the like.

  Examples of the polymerization initiator that can be used in obtaining the acrylic resin include benzoyl peroxide, t-butyl hydroperoxide, cumene hydroperoxide, 1,1,3,3-tetramethylbutyl hydroperoxide, t -Hexyl peroxide, t-butyl peroxide, 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate, t-hexylperoxy-2-ethylhexanoate, t-butylperoxy Organic peroxides such as 2-ethylhexanoate and lauroyl peroxide; 2,2′-azobisisobutyronitrile, 2,2′-azobis (2,4-dimethylvaleronitrile), 2,2 ′ -Azo compounds such as azobis (2-methylbutyronitrile);

  Further, the adhesive resin preferably contains a crosslinking agent for the purpose of increasing the holding power as the adhesive layer. Examples of the crosslinking agent include polyfunctional compounds such as isocyanate, epoxy, melamine, urea, and metal chelate. The content of the crosslinking agent is preferably 0.01% by mass or more and 10% by mass or less with respect to the total solid content (adhesive sheet component) of the adhesive resin. When a cross-linking agent is contained, after the pressure-sensitive adhesive resin is applied, the cross-linking reaction can be further advanced by heating or aging at an appropriate temperature as necessary.

  The glass transition temperature of the adhesive resin is preferably −80 ° C. or higher and 5 ° C. or lower, and more preferably −70 ° C. or higher and −20 ° C. or lower. The molecular weight of the adhesive resin is preferably 10,000 to 3,000,000, and more preferably 50,000 to 2,000,000 in terms of weight average molecular weight. When the weight average molecular weight of the pressure-sensitive adhesive resin is less than 10,000, when forming the pressure-sensitive adhesive layer, the viscosity is too low and the fluidity becomes too large, making it difficult to form a uniform layer as a sheet. On the other hand, if it exceeds 3,000,000, the viscosity becomes too high and the leveling action is not sufficiently developed, and it becomes difficult to form a uniform layer as well.

(Transparent conductive thin film layer)
In the laminate of the present invention, a transparent conductive thin film layer can be provided on the surface opposite to the surface on which the adhesive layer of the second transparent plastic film is provided. Thereby, it can use for electronic paper, organic EL, a solar cell, etc. as a transparent conductive laminated film.
Examples of the material for forming the transparent conductive thin film include inorganic substances such as indium oxide, tin oxide, zinc oxide, indium-tin composite oxide, tin-antimony composite oxide, zinc-aluminum composite oxide, and indium-zinc composite oxide. Conductive polymers such as polyaniline, polypyrrole, polyacetylene, polythiophene, and PEDOT (poly (3,4-ethylenedithiothiophene)); ultrafine conductive carbon fibers (carbon nanotubes, carbon nanohorns, carbon nanowires, etc.) dispersed in the polymer Organic matter; graphene; and the like. Of these, indium-tin composite oxides are preferable from the viewpoints of environmental stability and circuit processability.

  The layer structure of the transparent conductive thin film may be a single layer structure or a laminated structure of two or more layers. In the case of a transparent conductive thin film having a laminated structure of two or more layers, the materials (metal oxide etc.) constituting each layer may be the same or different.

  As a method for forming a transparent conductive thin film, a vacuum deposition method, a sputtering method, a CVD method, an ion plating method, a spray method, and the like are known, and the film thickness to be formed is selected from these known methods. Depending on the situation, it can be appropriately selected. In particular, the sputtering method is preferable from the viewpoint of reducing the variation in film thickness. At this time, oxygen, nitrogen, or the like may be introduced as a reactive gas, or means such as ozone addition, plasma irradiation, or ion assist may be used in combination. In addition, a bias such as direct current, alternating current, and high frequency may be applied to the substrate as long as the object of the present invention is not impaired.

  The film thickness of the transparent conductive thin film is preferably 4 nm or more, more preferably 10 nm or more. When the film thickness of the transparent conductive thin film is less than 4 nm, it is difficult to form a continuous thin film, and it is difficult to obtain good conductivity. The film thickness of the transparent conductive thin film is preferably 200 nm or less, more preferably 150 nm or less. When the film thickness of the transparent conductive thin film is larger than 200 nm, there is a possibility that cracks are likely to occur when bent.

  The surface resistance of the laminate of the present invention in which a transparent conductive thin film layer is laminated is preferably 5 to 1000 Ω / □, more preferably 10 to 600 Ω / □. When the surface resistance value is in the above range, it can be used as a transparent conductive laminated film for electronic paper, organic EL, solar cells and the like. On the other hand, if the surface resistance value is out of the above range, the response speed of the device may be slow, which is not preferable.

The laminate of the present invention preferably has a total light transmittance of 87% or more. When the total light transmittance is less than 87%, when used as an electrode substrate such as electronic paper, the transparency of the device tends to be low and the visibility tends to be poor. In order to set the total light transmittance to 87% or more, in particular, the refractive index difference | n ₃ −n ₁ | between the inorganic thin film layer and the first transparent plastic film and the refractive index difference between the inorganic thin film layer and the adhesive layer | n It is effective to reduce ₃ −n ₂ |, and it is sufficient to satisfy the relationship (i) and (ii) above. When the relationship of (i) and (ii) is not satisfied (that is, when the value of | n ₃ −n ₁ | or the value of | n ₃ −n ₂ | exceeds 0.2), the transmittance is 87% or more It becomes difficult to do. In addition, the total light transmittance of a laminated body can be measured by the method mentioned later in an Example, for example.
The laminate of the present invention preferably has a color b value of -1.0% to 4.0%. When the color b value is less than −1.0%, the blueness of the device becomes strong. On the other hand, when the color b value exceeds 4.0%, the yellowness becomes strong, and thus the visibility tends to be inferior. If the laminate satisfies the relationships (i) and (ii) above, the color b value falls within the above range. In addition, the color b value of a laminated body can be measured by the method mentioned later in an Example, for example.

The laminate of the present invention preferably has a water vapor transmission rate of less than 0.3 g / m ² / day. If it is 0.3 g / m ² / day or more, moisture gradually enters the device during long-term use of the device, and the device tends to deteriorate, which is not preferable. If it is a laminated body that satisfies the relationship (i) and (ii) above, the water vapor transmission rate is in the above range. In addition, the water vapor transmission rate of a laminated body can be measured by the method mentioned later in an Example, for example.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited at all by these Examples. The performance of the laminate was measured by the following method.

<Water vapor transmission rate>
In accordance with JIS-K7129 B method, the water vapor permeability was measured using a water vapor permeability measuring device (“AQUATRAN” manufactured by MOCON) in an atmosphere of a temperature of 40 ° C. and a humidity of 90% RH. The humidity control on the laminate was performed in such a direction that water vapor permeates from the first transparent plastic side to the second transparent plastic side.

<Total light transmittance>
Based on JIS-K7136, total light transmittance (%) was measured using “NDH-1001DP” manufactured by Nippon Denshoku Industries Co., Ltd.

<Color b value>
Based on JIS-K7105, color b value was measured with standard light C / 2 using a color difference meter (“ZE-2000” manufactured by Nippon Denshoku Industries Co., Ltd.).

<Surface resistance value>
Based on JIS-K7194, the surface resistance value was measured by a four-terminal method. For the measurement, “Lotest AMCP-T400” manufactured by Mitsubishi Yuka Co., Ltd. was used.

<Inorganic thin film layer, film thickness of transparent conductive thin film layer>
The film thickness of the inorganic thin film layer is the sample piece at the stage where the inorganic thin film layer is formed, and the film thickness of the transparent conductive thin film layer is the sample piece at the stage where the transparent conductive thin film layer is formed. The film sample piece was cut into a size of 1 mm × 10 mm and embedded in an epoxy resin for an electron microscope. This was fixed to a sample holder of an ultramicrotome, and a cross-sectional thin section parallel to the short side of the embedded sample piece was produced. Next, in a portion where the thin film of this section is not significantly damaged, a transmission electron microscope (“JEM-2010” manufactured by JEOL) was used to photograph at an acceleration voltage of 200 kV and a bright field at an observation magnification of 10,000 times. The film thickness was obtained from the obtained photograph.

<Refractive index of inorganic thin film layer and transparent conductive thin film layer>
The refractive index of the inorganic thin film layer is obtained by forming a sample for refractive index measurement by forming an inorganic thin film layer on a silicon wafer under the same film forming conditions as in each example or comparative example, The refractive index at 550 nm was measured using a meter (“FE-5000” manufactured by Otsuka Electronics Co., Ltd.), and the obtained value was taken as the refractive index of the inorganic thin film layer.
In addition, when the spectral transmission factor measurement was performed about the laminated | multilayer film provided with the inorganic thin film layer obtained in Example 1, and the refractive index was computed by performing fitting using optical simulation software with respect to the obtained data ( At this time, the film thickness of the inorganic thin film layer was the value obtained by the measurement method described above), and the calculated refractive index of the inorganic thin film layer was the refractive index of the inorganic thin film layer on the silicon wafer (refractive index measurement sample). It was confirmed that there was no great difference from the refractive index measured using
In addition, the refractive index of the transparent conductive thin film layer was prepared by forming a transparent conductive thin film layer on a silicon wafer under the same film forming conditions as in each example, and preparing a sample for refractive index measurement. It measured with the spectroscopic ellipsometer similarly to the refractive index of the said inorganic thin film layer.
For the laminated film provided with the transparent conductive thin film layer obtained in Example 7, the refractive index of the calculated transparent conductive thin film layer and the transparent conductive thin film layer on the silicon wafer were calculated in the same manner as described above. It was confirmed that there was no great difference between the refractive index (refractive index measured using a sample for refractive index measurement).

<Refractive index of adhesive layer and transparent plastic film>
According to JIS-K7142-1996 5.1 (Method A), the refractive index was measured with an Abbe refractometer using sodium D line as a light source.

[Example 1]
A biaxially oriented transparent polyethylene terephthalate (PET) film having a thickness of 125 μm and a refractive index of 1.65 was used as the first transparent plastic film, and a cured product layer was laminated on one side of the PET film.

When laminating the cured product layer, 100 parts by mass of a photopolymerization initiator-containing ultraviolet curable acrylic resin (“Seika Beam EXF-01J” manufactured by Dainichi Seika Kogyo Co., Ltd.) and toluene / methyl ethyl ketone (MEK) = 80 / A coating solution prepared by adding a mixed solvent of 20 (mass ratio) so that the solid content concentration is 50% by mass, and stirring and dissolving uniformly is applied onto a PET film using a Mayer bar. It applied so that it might become 5 micrometers. Thereafter, after drying at 80 ° C. for 1 minute, the coating film was formed by irradiating with ultraviolet rays (light quantity: 300 mJ / cm ² ) using an ultraviolet irradiation device (“UB042-5AM-W type” manufactured by Eye Graphics Co., Ltd.). Cured. Next, heat treatment was performed at 180 ° C. for 1 minute to reduce volatile components.

Next, in order to form an inorganic thin film layer, the first transparent plastic film on which the cured product layer was laminated was subjected to vacuum exposure. Specifically, the rewinding process was performed in a vacuum chamber. At this time, the pressure was 2 × 10 ⁻³ Pa, the exposure time was 20 minutes, and the temperature of the center roll was 40 ° C.

Then, the surface not forming a cured layer of the first transparent plastic film, by a DC magnetron sputtering method was formed inorganic thin layer of aluminum oxide (Al ₂ O _3). At this time, it was carried out after confirming that the water pressure in the vacuum chamber before sputtering was 1 × 10 ⁻⁴ Pa. In sputtering, Al (manufactured by Technofine) was used as a target, and DC power of 3 W / cm ² was applied. And Ar gas was flowed, it was set as the atmosphere of 0.4 Pa, and the center roll temperature was 0 degreeC. Further, the “Speedflo” manufactured by Gencoa is used while controlling the oxygen flow rate so that the discharge voltage during sputtering is constant. At this time, the discharge voltage when only Ar gas is supplied is 100%, Ar gas When the discharge voltage when O ₂ gas is supplied at 50 sccm is 0%, the discharge voltage is set to 50%. The inorganic thin film layer thus formed had a thickness of 40 nm and a refractive index of 1.59.

Next, on the inorganic thin film layer formed above, the 2nd transparent plastic film was bonded through the adhesive layer, and the laminated body was produced. Specifically, an adhesive layer having a refractive index of 1.52 is formed on the inorganic thin film layer by applying an acrylic adhesive resin (thickness 25 μm, sheet-like material), and then the adhesive layer A biaxially oriented transparent polyethylene terephthalate (PET) film having a thickness of 50 μm and a refractive index of 1.65 was laminated as a second transparent plastic film.
When the water vapor transmission rate, the total light transmittance, and the color b value were evaluated for the obtained laminate, the results shown in Table 1 were obtained.

[Example 2]
In depositing the inorganic thin film layer, a laminate was produced in the same manner as in Example 1 except that the discharge voltage was changed to change the thickness of the inorganic thin film layer to 20 nm.
The refractive index of the inorganic thin film layer of the obtained laminate was as shown in Table 1. Moreover, when the water vapor | steam transmittance | permeability, the total light transmittance, and the color b value were evaluated about the obtained laminated body, it became the result shown in Table 1.

Example 3
In depositing the inorganic thin film layer, a laminate was produced in the same manner as in Example 1 except that the discharge voltage was changed to change the thickness of the inorganic thin film layer to 10 nm.
The refractive index of the inorganic thin film layer of the obtained laminate was as shown in Table 1. Moreover, when the water vapor | steam transmittance | permeability, the total light transmittance, and the color b value were evaluated about the obtained laminated body, it became the result shown in Table 1.

Example 4
In depositing the inorganic thin film layer, a laminate was produced in the same manner as in Example 1 except that the discharge voltage was changed to change the thickness of the inorganic thin film layer to 100 nm.
The refractive index of the inorganic thin film layer of the obtained laminate was as shown in Table 1. Moreover, when the water vapor | steam transmittance | permeability, the total light transmittance, and the color b value were evaluated about the obtained laminated body, it became the result shown in Table 1.

Example 5
In depositing the inorganic thin film layer, a laminate was produced in the same manner as in Example 1 except that the discharge voltage was changed to change the thickness of the inorganic thin film layer to 150 nm.
The refractive index of the inorganic thin film layer of the obtained laminate was as shown in Table 1. Moreover, when the water vapor | steam transmittance | permeability, the total light transmittance, and the color b value were evaluated about the obtained laminated body, it became the result shown in Table 1.

Example 6
When forming the inorganic thin film layer, a laminate was produced in the same manner as in Example 1 except that the discharge voltage was changed to change the thickness of the inorganic thin film layer to 200 nm.
The refractive index of the inorganic thin film layer of the obtained laminate was as shown in Table 1. Moreover, when the water vapor | steam transmittance | permeability, the total light transmittance, and the color b value were evaluated about the obtained laminated body, it became the result shown in Table 1.

Example 7
A transparent conductive thin film layer made of an indium-tin composite oxide was formed on the second transparent plastic film (outer surface) of the laminate produced in Example 1 by DC magnetron sputtering. At this time, it was carried out after confirming that the water pressure in the vacuum chamber before sputtering was 1 × 10 ⁻⁴ Pa. In sputtering, indium oxide containing 10% by mass of tin oxide (Sumitomo Metal Mining Co., Ltd., density 7.1 g / cm ³ ) was used as a target, and DC power of ² W / cm ² was applied. Then, Ar gas and O ₂ gas were flowed at a flow velocity at which the surface resistance value was minimized, the atmosphere was 0.4 Pa, and the center roll temperature was 0 ° C. In addition, while constantly monitoring the oxygen partial pressure of the atmosphere with a sputtering process monitor (“XPR2” manufactured by LEYBOLD INFICON), an oxygen gas flow meter is used to maintain a constant degree of oxidation in the indium-tin composite oxide thin film layer. And back to DC power. The transparent conductive thin film layer thus formed had a thickness of 20 nm and a refractive index of 1.85.
When the obtained laminate was evaluated for water vapor transmission rate, total light transmittance, color b value, and surface resistance value on the transparent conductive thin film layer side, the results shown in Table 1 were obtained.

Example 8
A laminated body was obtained in the same manner as in Example 1 except that 10 parts by mass of silica particles having an average particle diameter of 0.5 μm were added to the coating solution for laminating the cured product layer. In the same manner as in Example 7, a transparent conductive thin film layer was laminated to produce a laminate.
When the obtained laminate was evaluated for water vapor transmission rate, total light transmittance, color b value, and surface resistance value on the transparent conductive thin film layer side, the results shown in Table 1 were obtained.

Example 9
As the inorganic thin film layer, a laminate was produced in the same manner as in Example 1 except that an inorganic thin film layer made of Al ₂ O ₃ —SiO ₂ was formed by DC magnetron sputtering. The Al ₂ O ₃ —SiO ₂ film was formed after confirming that the water pressure in the vacuum chamber before sputtering was 1 × 10 ⁻⁴ Pa. In sputtering, Al—Si (composition ratio Al: Si = 5: 5, manufactured by High Purity Chemical Co., Ltd.) was used as a target, and DC power of 3 W / cm ² was applied. And Ar gas was flowed, it was set as the atmosphere of 0.4 Pa, and the center roll temperature was 0 degreeC. Further, the “Speedflo” manufactured by Gencoa is used while controlling the oxygen flow rate so that the discharge voltage during sputtering is constant. At this time, the discharge voltage when only Ar gas is supplied is 100%, Ar gas When the discharge voltage when O ₂ gas is supplied at 50 sccm is 0%, the discharge voltage is set to 50%. The inorganic thin film layer thus formed had a thickness of 40 nm and a refractive index of 1.52.
When the water vapor transmission rate, the total light transmittance, and the color b value were evaluated for the obtained laminate, the results shown in Table 1 were obtained.

Example 10
Example 1 except that a cycloolefin film (“ZF-14” manufactured by Nippon Zeon Co., Ltd.) having a thickness of 100 μm and a refractive index of 1.53 was used as the first transparent plastic film, and the cured product layer was not laminated. A laminate was produced in the same manner as described above.
When the water vapor transmission rate, the total light transmittance, and the color b value were evaluated for the obtained laminate, the results shown in Table 1 were obtained.

Example 11
On the second transparent plastic film (outer surface) of the laminate produced in Example 10, a transparent conductive thin film layer made of indium-tin composite oxide was formed in the same manner as in Example 7. A laminate was produced.
When the obtained laminate was evaluated for water vapor transmission rate, total light transmittance, color b value, and surface resistance value on the transparent conductive thin film layer side, the results shown in Table 1 were obtained.

Example 12
In forming the inorganic thin film layer, a laminate was prepared in the same manner as described in Example 10 except that an inorganic thin film layer made of Al ₂ O ₃ —SiO ₂ was formed in the same manner as in Example 9.
When the water vapor transmission rate, the total light transmittance, and the color b value were evaluated for the obtained laminate, the results shown in Table 1 were obtained.

[Comparative Example 1]
As the inorganic thin film layer, a laminate was produced in the same manner as in Example 1 except that an inorganic thin film layer made of aluminum nitride was formed by DC magnetron sputtering. The aluminum nitride film was formed after confirming that the water pressure in the vacuum chamber before sputtering was 1 × 10 ⁻⁴ Pa. In sputtering, Al (manufactured by Technofine) was used as a target, and DC power of ² W / cm ² was applied. And Ar gas was flowed, it was set as the atmosphere of 0.4 Pa, and the center roll temperature was 0 degreeC. In addition, using “Speedflo” manufactured by Gencoa, while controlling the nitrogen flow rate so that the discharge voltage during sputtering is constant, the discharge voltage when only Ar gas is supplied is 100%, Ar gas When the discharge voltage when flowing N ₂ gas at 50 sccm is 0%, the discharge voltage is set to 50%. The inorganic thin film layer thus formed had a thickness of 40 nm and a refractive index of 2.12.
When the water vapor transmission rate, the total light transmittance, and the color b value were evaluated for the obtained laminate, the results shown in Table 1 were obtained.

[Comparative Example 2]
A laminate was prepared in the same manner as in Example 1 except that an inorganic thin film layer made of zirconia-silicon composite oxide (ZrO ₂ —SiO ₂ ) was formed as a thin film layer by DC magnetron sputtering. . The zirconia-silicon composite oxide film was formed after confirming that the water pressure in the vacuum chamber before sputtering was 1 × 10 ⁻⁴ Pa. In sputtering, ZrSi ₂ (manufactured by Mitsui Kinzoku Co., Ltd.) was used as a target, and DC power of ² W / cm ² was applied. And Ar gas was flowed, it was set as the atmosphere of 0.4 Pa, and the center roll temperature was 0 degreeC. Further, the “Speedflo” manufactured by Gencoa is used while controlling the oxygen flow rate so that the discharge voltage during sputtering is constant. At this time, the discharge voltage when only Ar gas is supplied is 100%, Ar gas When the discharge voltage when flowing 50 sccm of O ₂ gas was 0%, the discharge voltage was set to a value of 50%. The inorganic thin film layer thus formed had a thickness of 40 nm and a refractive index of 1.80.
When the water vapor transmission rate, the total light transmittance, and the color b value were evaluated for the obtained laminate, the results shown in Table 1 were obtained.

[Comparative Example 3]
Example 1 except that a copolymer film of hexafluoropropylene having a thickness of 100 μm and a refractive index of 1.34 (“Nephron FEP film NF-0100” manufactured by Daikin Chemical Industries, Ltd.) was used as the first transparent plastic film. Similarly, a laminate was produced.
When the water vapor transmission rate, the total light transmittance, and the color b value were evaluated for the obtained laminate, the results shown in Table 1 were obtained.

Table from 1 results evident, | - _| and values, | refractive index n ₃ of the inorganic thin film layer refractive index n ₁ of the first transparent plastic film refractive index of the inorganic thin layer n ₃ - the pressure-sensitive adhesive layer The laminates of Examples 1 to 12 in which both the values of the refractive index n ₂ | are in the range of the present invention had excellent transparency and excellent water vapor barrier properties.
On the other hand, | the refractive index n ₃ of the inorganic thin film layer−the refractive index n ₁ | of the first transparent plastic film and the refractive index n ₃ of the inorganic thin film layer−the refractive index n ₂ of the adhesive layer Comparative Example ₂ in which only the value of the refractive index n ₃ of the inorganic thin film layer−the refractive index n ₂ of the pressure sensitive adhesive layer is out of the range of the present invention. The laminates had a total light transmittance of 82% to 85%, and all had insufficient transparency. Also, the laminate of Comparative Example 3 in which only the value of | refractive index n ₃ of the inorganic thin film layer−refractive index n ₁ | of the first transparent plastic film is out of the scope of the present invention is sufficient for the thickness of the inorganic thin film layer (40 nm ), The water vapor transmission rate was as high as 0.25 g / m ² / day, and the water vapor barrier property was inferior.

  Since the laminated body of this invention is excellent in transparency and water vapor | steam barrier property, it is used especially suitably as a board | substrate of electronic materials, such as electronic paper, a solar cell, and organic EL.

1: first transparent plastic film 2: cured product layer 3: inorganic thin film layer 4: adhesive layer 5: second transparent plastic film 6: transparent conductive thin film layer 10: laminate
11: Laminated body with transparent conductive thin film

Claims (6)

A laminated body in which a second transparent plastic film is laminated via an adhesive layer on a surface of the laminated film in which an inorganic thin film layer made of an inorganic material is laminated on one side of the first transparent plastic film. The refractive index n _{1 of} the first transparent plastic film, the refractive index n ₂ of the adhesive layer, the refractive index n ₃ of the inorganic thin film layer, and the refractive index n _{4 of} the second transparent plastic film are as follows ( A laminated body satisfying the relationships i) to (iii), wherein the inorganic thin film layer contains Al ₂ O ₃ .
| N ₃ −n ₁ | ≦ 0.2 (i)
| N ₃ −n ₂ | ≦ 0.2 (ii)
| N ₃ −n ₄ | ≦ 0.2 (iii) The laminate according to claim 1, wherein | n ₃ −n ₄ | ≦ 0.09.   The layered product according to claim 1 or 2 whose film thickness of said inorganic thin film layer is 10-200 nm. The laminated body in any one of Claims 1-3 which provided the transparent conductive thin film layer in the surface on the opposite side to the surface which provided the adhesive layer of the said 2nd transparent plastic film. The laminate according to any one of claims 1 to 4 , wherein a hard coat layer is provided on a surface opposite to the surface on which the inorganic thin film layer of the first transparent plastic film is provided. The laminate according to claim 5 , wherein the hard coat layer is antiglare treated.