WO2017131201A1

WO2017131201A1 - Optical layered body

Info

Publication number: WO2017131201A1
Application number: PCT/JP2017/003050
Authority: WO
Inventors: 幸大宮本; 智剛梨木
Original assignee: 日東電工株式会社
Priority date: 2016-01-29
Filing date: 2017-01-27
Publication date: 2017-08-03
Also published as: CN108603964B; JP2017134371A; JP6938112B2; CN108603964A; KR20180109897A

Abstract

An optical layered body, which functions as a barrier film and a polarizing plate and in which the occurrence of cracks is suppressed, is provided. This optical layered body includes a polarizer, a substrate, a first oxide layer containing ZnO, Al and SiO₂, and a second oxide layer composed of SiO₂ in this order. The surface roughness Ra of the surface of the substrate on the first oxide layer side is 0.30-50 nm. In one embodiment, the optical layered body has a moisture permeability of 3.0 × 10^-2 g/m²/24hr or less.

Description

Optical laminate

The present invention relates to an optical laminate. In more detail, this invention relates to the optical laminated body which can function as a barrier film and a polarizing plate.

Conventionally, a barrier film is used for an image display device (for example, a liquid crystal display device, an organic electroluminescence (EL) display device). In the development of such a barrier film, a transparent oxide obtained by adding SiO ₂ to an Al—Zn—O (aluminum-added zinc oxide) film as a barrier film having a high film forming speed, a low refractive index, and a good gas barrier property. A material film has been proposed (Patent Document 1). However, this transparent oxide film has extremely insufficient chemical resistance (for example, acid resistance and alkali resistance).

JP 2013-189657 A

The present invention has been made to solve the above-described conventional problems, and an object of the present invention is to provide an optical layered body that functions as a barrier film and a polarizing plate and that suppresses the occurrence of cracks. It is in.

The optical layered body of the present invention has a polarizer, a base material, a first oxide layer containing ZnO, Al and SiO ₂ and a second oxide layer composed of SiO ₂ in this order. The surface roughness Ra of the surface of the substrate on the first oxide layer side is 0.30 nm to 50 nm.
In one embodiment, the optical layered body further includes a protective layer on at least one side of the polarizer.
In one embodiment, the thickness of the first oxide layer is 10 nm to 100 nm.
In one embodiment, the thickness of the second oxide layer is 10 nm to 100 nm.
In one embodiment, the optical laminate, moisture permeability is less than ^{^{3.0 × 10 -2 g / m 2}} / 24hr.
In one embodiment, the optical laminate, the gas barrier property is ^{^{1.0 × 10 -7 g / m 2}} /24hr~0.5g/m 2 / 24hr.
In one embodiment, the optical laminate, the moisture permeability after dropping hydrochloric acid or sodium hydroxide solution is less than ^{^{1.0 × 10 -1 g / m 2}} / 24hr.

According to the embodiment of the present invention, a laminated structure of a first oxide layer containing ZnO, Al, and SiO ₂ and a second oxide layer composed of SiO ₂ is adopted as a barrier layer, and further a polarizer. By laminating the optical laminate, it is possible to realize an optical laminate having excellent moisture permeability and gas barrier properties and excellent chemical resistance, flexibility and heat resistance. That is, it is possible to realize an optical laminate that can exhibit an excellent function as a barrier film and a polarizing plate. Furthermore, in the embodiment of the present invention, by setting the surface roughness Ra of the surface on the first oxide layer side of the base material to a predetermined value or more, excellent characteristics as the barrier film and the polarizing plate as described above. While maintaining the above, the occurrence of cracks in the first oxide layer and / or the second oxide layer can be remarkably suppressed.

It is a schematic sectional drawing of the optical laminated body by one Embodiment of this invention.

Hereinafter, representative embodiments of the present invention will be described, but the present invention is not limited to these embodiments.

A. FIG. 1 is a schematic cross-sectional view of an optical laminate according to one embodiment of the present invention. The optical laminated body 100 of this embodiment has the polarizer 41, the base material 10, the 1st oxide layer 20, and the 2nd oxide layer 30 in this order. By having such a configuration, the optical layered body according to the embodiment of the present invention can function as both a barrier film and a polarizing plate of an image display device. Practically, protective layers 42 and / or 43 are provided on at least one side of the polarizer (in the illustrated example,

protective layers

42 and 43 are provided on both sides of the polarizer 41). In this case, typically, the polarizer 41 is laminated on the substrate 10 as the polarizing plate 40 and can be introduced into the optical laminate. The first oxide layer 20 may include ZnO, Al and SiO _2. The second oxide layer 30 is composed of SiO _2. The thickness of the first oxide layer 20 is preferably 10 nm to 100 nm. The thickness of the second oxide layer 30 is preferably 10 nm to 100 nm.

In the embodiment of the present invention, the surface roughness Ra of the surface of the substrate 10 on the first oxide layer 20 side is 0.30 nm to 50 nm. When the surface has such a surface roughness, the following effects can be obtained: In the optical laminate, the dimensional change (typically shrinkage) of the polarizer is significantly larger than that of other components. . Therefore, stress and strain due to the contraction of the polarizer propagate to the base material, the first oxide layer, and the second oxide layer, and as a result, in the first oxide layer and / or the second oxide layer. Cracks may occur in the thickness direction. Here, as described above, by setting the surface roughness of the surface of the base material on the first oxide layer side to a predetermined value or more, the adhesion between the base material and the first oxide layer is improved. The first oxide layer (as a result, the second oxide layer) can follow the dimensional change. As a result, the generation of cracks mainly resulting from the contraction of the polarizer is remarkably suppressed, and the excellent barrier property due to the laminated structure of the first oxide layer and the second oxide layer can be maintained. Therefore, it is possible to integrate the polarizer and the barrier film (a laminate of the base material, the first oxide layer, and the second oxide layer). This is because the thickness of the image display device and the manufacturing process are reduced. Can contribute significantly to simplification. This is a knowledge obtained by trial and error in order to solve the problem recognized only after integrating the polarizer and the barrier film, and is an unexpectedly excellent effect.

The optical layered body has a barrier property against moisture and gas (for example, oxygen). 40 ° C. of the optical stack, the water vapor transmission rate at 90% RH conditions (moisture permeability) is preferably 1.0 × ¹⁰ -1 ^g / m less than 2/24 hr or. From the viewpoint of barrier properties, the lower the lower limit of moisture permeability, the better. Measurement limit of moisture permeability, for example, ^{^{0.1 × 10 -6 g / m 2}} / 24hr approximately. In one embodiment, from the viewpoint of releasing the outgassing over time generated from the device composition, the lower limit of the moisture permeability, for example, ^{^{0.1 × 10 -4 g / m 2}} / 24hr. The preferable upper limit of moisture permeability can vary depending on the application. The upper limit of moisture permeability, for example, an image display device of the indoor (e.g., PC display) in applications was ^{^{5.0 × 10 -2 g / m 2}} / 24hr, outdoor image display apparatus in (digital signage) applications 3.0 × a ^{^{10 -2 g / m 2 / 24hr}} , the indoor harsh environment applications such as automotive display is ^{^{1.0 × 10 -2 g / m 2}} / 24hr. 60 ° C. of the optical stack, gas barrier properties 90% RH conditions is preferably ^{^{1.0 × 10 -7 g / m 2}} /24hr~0.5g/m 2 / 24hr, more preferably 1. 0 × a ^{^{^{10 -7 g / m 2 /24hr~0.1g/m 2}}} / 24hr. When the moisture permeability and gas barrier properties are within such ranges, when the optical laminate is bonded to the image display device, the image display device can be well protected from moisture and oxygen in the air. Both moisture permeability and gas barrier properties can be measured according to JIS K7126-1.

The optical layered body preferably has chemical resistance. More specifically, the optical laminate preferably has acid resistance and alkali resistance. In this specification, the term “acid resistance” means that a 2% hydrochloric acid solution (pH 0.3) is dropped onto the optical laminate, and the moisture permeability after wiping off the hydrochloric acid solution after 10 minutes is 1.0 × 10 ⁻¹ g. / refers to ^m is less than 2/24 hr or. Further, the "alkali resistance", was added dropwise a 2% sodium hydroxide solution (pH 13.7) to the optical stack, moisture permeability after wiping sodium hydroxide solution after 10 minutes is 1.0 × 10 ^- It refers to less than ¹ g ^/ m 2 ^/ 24hr. The achievement of such excellent chemical resistance while maintaining the desired barrier properties and transparency as described above is one of the achievements of the present invention.

The optical layered body has a flexibility such that cracks and cracks do not occur even when it is bent with a curvature radius of 7 mm, more preferably with a curvature radius of 5 mm. By adopting a laminated structure of the predetermined first oxide layer and the second oxide layer, it is possible to achieve both excellent chemical resistance and excellent flexibility and heat resistance (described later).

Optical stack are preferably 500 hours at 95 ° C., more preferably 600 hours, more preferably heat as moisture permeability be heated 700 hours is less than ^{^{1.0 × 10 -1 g / m 2}} / 24hr Have sex. By adopting a laminated structure of the predetermined first oxide layer and second oxide layer, it is possible to achieve both excellent chemical resistance and excellent flexibility and heat resistance.

In one embodiment, the optical layered body of the present invention is elongated. The long optical laminate can be stored and / or transported, for example, wound in a roll. Since the optical layered body is excellent in flexibility, no problem occurs even if it is wound into a roll. In this case, the absorption axis direction of the polarizer is typically substantially parallel to the longitudinal direction. If it is such a structure, an optical laminated body can be produced by what is called a roll-to-roll.

If necessary, a retardation layer (not shown) may be provided between the polarizing plate 40 and the base material 10 and / or on the opposite side of the polarizing plate 40 from the base material. Optical properties of the retardation layer (for example, refractive index ellipsoid, in-plane retardation, thickness direction retardation, Nz coefficient, wavelength dispersion characteristic, photoelastic coefficient), mechanical characteristics, number of arrangements, combinations, etc. Appropriately. For example, a retardation layer that exhibits the wavelength dependence of reverse dispersion and can function as a so-called λ / 4 plate can be disposed on the opposite side of the substrate of the polarizing plate 40. In this case, the angle formed by the slow axis of the retardation layer and the absorption axis of the polarizer is typically about 45 °. With such a configuration, a good circular polarization function is imparted to the optical layered body, so that the optical layered body can function well as an antireflection film of an image display device.

Hereinafter, components of the optical laminate will be described.

B. Polarizer As described above, the polarizer 41 is typically laminated on the substrate 10 as the polarizer 40 and can be introduced into the optical laminate. The polarizing plate 40 (substantially the protective layer 42, or the polarizer 41 in the absence of the protective layer 42) may be any suitable pressure-sensitive adhesive layer (for example, acrylic pressure-sensitive adhesive layer) or adhesive layer (for example, It is bonded to the substrate 10 via a PVA resin adhesive layer).

B-1. Polarizer Any appropriate polarizer can be adopted as the polarizer 41. For example, the resin film forming the polarizer may be a single-layer resin film or a laminate of two or more layers.

Specific examples of polarizers composed of a single-layer resin film include hydrophilic polymer films such as polyvinyl alcohol (PVA) films, partially formalized PVA films, and ethylene / vinyl acetate copolymer partially saponified films. In addition, there may be mentioned polyene-based oriented films such as those subjected to dyeing treatment and stretching treatment with dichroic substances such as iodine and dichroic dyes, PVA dehydrated products and polyvinyl chloride dehydrochlorinated products. Preferably, a polarizer obtained by dyeing a PVA film with iodine and uniaxially stretching is used because of excellent optical properties.

The dyeing with iodine is performed, for example, by immersing a PVA film in an aqueous iodine solution. The stretching ratio of the uniaxial stretching is preferably 3 to 7 times. The stretching may be performed after the dyeing treatment or may be performed while dyeing. Moreover, you may dye | stain after extending | stretching. If necessary, the PVA film is subjected to swelling treatment, crosslinking treatment, washing treatment, drying treatment and the like. For example, by immersing the PVA film in water and washing it before dyeing, not only can the surface of the PVA film be cleaned of dirt and anti-blocking agents, but the PVA film can be swollen to cause uneven staining. Can be prevented.

As a specific example of a polarizer obtained by using a laminate, a laminate of a resin substrate and a PVA resin layer (PVA resin film) laminated on the resin substrate, or a resin substrate and the resin Examples thereof include a polarizer obtained by using a laminate with a PVA resin layer applied and formed on a substrate. For example, a polarizer obtained by using a laminate of a resin base material and a PVA resin layer applied and formed on the resin base material may be obtained by, for example, applying a PVA resin solution to a resin base material and drying it. A PVA-based resin layer is formed thereon to obtain a laminate of a resin base material and a PVA-based resin layer; the laminate is stretched and dyed to make the PVA-based resin layer a polarizer; obtain. In the present embodiment, stretching typically includes immersing the laminate in an aqueous boric acid solution and stretching. Furthermore, the stretching may further include, if necessary, stretching the laminate in the air at a high temperature (for example, 95 ° C. or higher) before stretching in the aqueous boric acid solution. The obtained resin base material / polarizer laminate may be used as it is (that is, the resin base material may be used as a protective layer of the polarizer), and the resin base material is peeled from the resin base material / polarizer laminate. Any appropriate protective layer according to the purpose may be laminated on the release surface. Details of a method for manufacturing such a polarizer are described in, for example, Japanese Patent Application Laid-Open No. 2012-73580. This publication is incorporated herein by reference in its entirety.

The thickness of the polarizer is preferably 15 μm or less, more preferably 1 μm to 12 μm, still more preferably 3 μm to 10 μm, and particularly preferably 3 μm to 8 μm. When the thickness of the polarizer is in such a range, curling during heating can be satisfactorily suppressed, and good appearance durability during heating can be obtained. Furthermore, if the thickness of the polarizer is in such a range, it can contribute to the thinning of the optical laminate (as a result, the organic EL display device).

The polarizer preferably exhibits absorption dichroism at any wavelength between 380 nm and 780 nm. The single transmittance of the polarizer is preferably 43.0% to 46.0%, more preferably 44.5% to 46.0%. The polarization degree of the polarizer is preferably 97.0% or more, more preferably 99.0% or more, and further preferably 99.9% or more.

B-2. Protective layer The protective layer 42 is formed of any suitable film that can be used as a protective layer for a polarizer. Specific examples of the material as the main component of the film include cellulose resins such as triacetyl cellulose (TAC), polyester-based, polyvinyl alcohol-based, polycarbonate-based, polyamide-based, polyimide-based, polyethersulfone-based, and polysulfone-based materials. And transparent resins such as polystyrene, polynorbornene, polyolefin, (meth) acryl, and acetate. Further, thermosetting resins such as (meth) acrylic, urethane-based, (meth) acrylurethane-based, epoxy-based, and silicone-based or ultraviolet curable resins are also included. In addition to this, for example, a glassy polymer such as a siloxane polymer is also included. Further, a polymer film described in JP-A-2001-343529 (WO01 / 37007) can also be used. As a material for this film, for example, a resin composition containing a thermoplastic resin having a substituted or unsubstituted imide group in the side chain and a thermoplastic resin having a substituted or unsubstituted phenyl group and nitrile group in the side chain For example, a resin composition having an alternating copolymer of isobutene and N-methylmaleimide and an acrylonitrile / styrene copolymer can be mentioned. The polymer film can be, for example, an extruded product of the resin composition.

The optical layered body of the present invention is typically disposed on the viewing side of the image display device, and the protective layer 42 is typically disposed on the viewing side. Therefore, the protective layer 42 may be subjected to surface treatment such as hard coat treatment, antireflection treatment, antisticking treatment, and antiglare treatment as necessary. Further / or, if necessary, the protective layer 42 is provided with a treatment for improving visibility when viewed through polarized sunglasses (typically, an (elliptical) circular polarization function is imparted, an ultrahigh phase difference is provided. May be applied). By performing such processing, excellent visibility can be achieved even when the display screen is viewed through a polarizing lens such as polarized sunglasses. Therefore, the optical laminate can be suitably applied to an image display device that can be used outdoors.

The thickness of the protective layer 42 is preferably 20 μm to 200 μm, more preferably 30 μm to 100 μm, and still more preferably 35 μm to 95 μm.

The protective layer 43 is preferably optically isotropic. In this specification, “optically isotropic” means that the in-plane retardation Re (550) is 0 nm to 10 nm and the thickness direction retardation Rth (550) is −10 nm to +10 nm. The in-plane retardation Re (550) of the substrate is preferably 0 nm to 5 nm, and the thickness direction retardation Rth (550) is preferably -5 nm to +5 nm. “Re (550)” is the in-plane retardation of the film measured with light having a wavelength of 550 nm at 23 ° C., and the formula: Re = (nx−ny) where d (nm) is the thickness of the film. It is calculated | required by xd. “Rth (550)” is a retardation in the thickness direction of the film measured with light having a wavelength of 550 nm at 23 ° C. When the thickness of the film is d (nm), the formula: Re = (nx−nz) × determined by d. Here, “nx” is the refractive index in the direction in which the in-plane refractive index is maximum (that is, the slow axis direction), and “ny” is the direction orthogonal to the slow axis in the plane (that is, fast phase). (Nz direction), and “nz” is the refractive index in the thickness direction.

The material, thickness, and the like of the protective layer 43 are as described above for the protective layer 42.

The protective layers 42 and 43 are typically bonded to the polarizer 41 via any appropriate adhesive layer (for example, a PVA resin adhesive layer).

C. Base material The base material 10 is preferably transparent. The total light transmittance of visible light (for example, light having a wavelength of 550 nm) is preferably 85% or more, more preferably 90% or more, and further preferably 95% or more.

The substrate 10 is optically isotropic in one embodiment. With such a configuration, when the optical laminate is applied to an image display device, adverse effects on the display characteristics of the image display device can be prevented.

The average refractive index of the substrate is preferably less than 1.7, more preferably 1.59 or less, and further preferably 1.4 to 1.55. When the average refractive index is in such a range, there is an advantage that back surface reflection can be suppressed and high light transmittance can be achieved.

As described above, the surface roughness Ra of the surface on the first oxide layer side of the substrate is 0.30 nm or more, preferably 0.40 nm or more, more preferably 0.50 nm or more, and still more preferably. Is 0.60 nm or more. The upper limit of the surface roughness Ra of the surface is, for example, 50 nm. If the surface roughness of the surface is in such a range, as described above, excellent adhesion between the substrate and the first oxide layer is realized, and as a result, the first due to the contraction of the polarizer. Cracks in the oxide layer and / or the second oxide layer (typically, cracks in the thickness direction) can be significantly suppressed. Further, by setting Ra to 0.3 nm to 50 nm, the transmittance of the optical laminate can be further improved. This is considered to be because a layer having an intermediate refractive index is formed by the first oxide layer entering the concave portion of the concave and convex portion of the substrate, and this functions as a refractive index matching layer. When Ra exceeds 50 nm, a so-called haze that appears to be visually cloudy due to light scattering occurs, and the effect of the layer having an intermediate refractive index may be offset. Such surface roughness can be realized by any appropriate roughening treatment. Examples of the roughening treatment include embossing, sand blasting, stretching and bending, and introduction of fine particles. The surface roughness Ra can be measured according to JIS B 0601.

As the material constituting the base material, any appropriate material that can satisfy the above characteristics can be used. Examples of the material constituting the substrate include resins having no conjugated system such as norbornene resins and olefin resins, resins having a cyclic structure such as a lactone ring and a glutarimide ring in the acrylic main chain, and polyester-based materials. Examples thereof include resins and polycarbonate resins. With such a material, when the base material is formed, the expression of the phase difference accompanying the orientation of the molecular chain can be kept small.

The base material may have a predetermined phase difference in another embodiment. For example, the substrate may have an in-plane retardation that can function as a so-called λ / 4 plate. With such a configuration, a good circular polarization function is imparted to the optical laminate without separately providing a retardation layer, so that the optical laminate is not only used as a barrier film for an image display device but also an antireflection film. As well. In this case, the angle formed by the slow axis of the substrate and the absorption axis of the polarizer 41 is typically about 45 °. Such a substrate can be formed, for example, by stretching a film of norbornene resin or polycarbonate resin under appropriate conditions.

The thickness of the substrate is preferably 10 μm to 50 μm or less, and more preferably 20 μm to 35 μm or less.

D. First Oxide Layer The first oxide layer 20 includes ZnO, Al, and SiO ₂ as described above. The first oxide layer preferably contains Al in a proportion of 2.5% to 3.5% by weight and SiO ₂ preferably in a proportion of 20.0% to 62.4% by weight with respect to the total weight. . ZnO is preferably the remaining amount. By containing ZnO in such a range, a layer excellent in amorphous property, barrier property, flexibility and heat resistance can be formed. By containing Al in such a range, the first oxide layer is typically formed by sputtering, but the conductivity of the target can be increased. By containing SiO ₂ in such a range, the refractive index of the first oxide layer can be reduced without causing abnormal discharge and without impairing the barrier property.

As described above, the thickness of the first oxide layer is preferably 10 nm to 100 nm, more preferably 10 nm to 60 nm, and still more preferably 20 nm to 40 nm. If the thickness is in such a range, there is an advantage that both high light transmittance and excellent barrier properties can be achieved.

The average refractive index of the first oxide layer is preferably 1.59 to 1.80. When the average refractive index is in such a range, there is an advantage that high light transmittance can be achieved.

The first oxide layer is preferably transparent. The first oxide layer preferably has a total light transmittance of visible light (for example, light having a wavelength of 550 nm) of 85% or more, more preferably 90% or more, and further preferably 95% or more. .

The first oxide layer can be typically formed on the substrate by sputtering. The first oxide layer can be formed by a sputtering method in an inert gas atmosphere containing oxygen using, for example, a sputtering target containing Al, SiO ₂ and ZnO. As a sputtering method, a magnetron sputtering method, an RF sputtering method, an RF superimposed DC sputtering method, a pulse sputtering method, a dual magnetron sputtering method, or the like can be employed. The heating temperature of the substrate is, for example, −8 ° C. to 200 ° C. The gas partial pressure of oxygen with respect to the whole atmospheric gas of oxygen and inert gas is, for example, 0.05 or more.

The details of the AZO film constituting the first oxide layer and the manufacturing method thereof are described in, for example, Japanese Patent Application Laid-Open No. 2013-189657. The description of the publication is incorporated herein by reference.

E. Second Oxide Layer As described above, the second oxide layer 30 is made of SiO ₂ (it may contain inevitable impurities). By forming such a second oxide layer on the surface of the first oxide layer, the chemical resistance and transparency of the optical laminate can be improved while maintaining good characteristics of the first oxide layer. It can be improved significantly. Furthermore, since the second oxide layer can function as a low refractive index layer, it is possible to impart good antireflection characteristics to the optical laminate.

As described above, the thickness of the second oxide layer is preferably 10 nm to 100 nm, more preferably 50 nm to 100 nm, and still more preferably 60 nm to 100 nm. When the thickness is in such a range, there is an advantage that both high light transmittance, excellent barrier properties, and excellent chemical resistance can be achieved.

The average refractive index of the second oxide layer is preferably 1.44 to 1.50. As a result, the second oxide layer can function well as a low refractive index layer (antireflection layer).

The second oxide layer is preferably transparent. In the second oxide layer, the total light transmittance of visible light (for example, light having a wavelength of 550 nm) is preferably 85% or more, more preferably 90% or more, and further preferably 95% or more. .

The second oxide layer can be formed on the first oxide layer, typically by sputtering. The second oxide layer is sputtered using, for example, Si, SiC, SiN, or SiO, and an inert gas containing oxygen (for example, argon, nitrogen, CO, CO ₂ , or a mixed gas thereof). Can be formed. Since both the first oxide layer and the second oxide layer contain SiO ₂ , the adhesion between the first oxide layer and the second oxide layer is very excellent. Therefore, in order to develop a sufficient barrier function at the interface between the first oxide layer and the second oxide layer, the thickness of the first oxide layer is 10 nm or more as described above. Is preferred. This is because the ratio of the so-called incubation layer, which is the initial growth film, can be sufficiently reduced, and an oxide layer having the desired physical properties can be formed. Further, the total thickness of the first oxide layer and the second oxide layer is preferably 200 nm or less, and more preferably 140 nm or less.

F. Use of optical laminate The optical laminate of the present invention can be suitably used as an optical member having the functions of both a barrier layer (barrier film) and a polarizing plate of an image display device. More specifically, the optical laminate of the present invention can be used as an optical member of a liquid crystal display device and an organic EL display device, preferably an organic EL display device, more preferably a bendable organic EL display device.

Hereinafter, the present invention will be specifically described by way of examples, but the present invention is not limited to these examples. In addition, the measuring method of each characteristic is as follows.

(1) Thickness The thicknesses of the first oxide layer and the second oxide layer were measured by observing a cross section using a transmission electron microscope (H-7650 manufactured by Hitachi, Ltd.). The thickness of other components of the optical laminate was measured using a film thickness meter (Digital Dial Gauge DG-205 manufactured by Peacock).
(2) Surface roughness Ra
Measurement was performed according to JIS B 0601. An optical surface roughness meter (manufactured by Veeco Metrology Group, trade name “Wyko NT9100”) was used as a measuring machine.
(3) Reliability The optical laminates obtained in the examples and comparative examples were cut into 50 mm × 50 mm sizes and used as measurement samples. This measurement sample was bonded to quartz glass, stored in an oven at 95 ° C. for 500 hours, measured for moisture permeability after storage, and evaluated according to the following criteria.
^{^{○: 1.0 × 10 -1 g /}} m 2 / 24hr less ^{^{×: 1.0 × 10 -1 g /}} m 2 / 24hr or more (4) obtained in moisture permeability Examples and Comparative Examples optical laminate A 10 cmφ circular shape was cut out and used as a measurement sample. About this measurement sample, moisture permeability was measured on 40 degreeC and 90% RH test conditions using "DELTATAPERM" by Technolox.
(5) Chemical resistance The optical laminates obtained in the examples and comparative examples were cut into a size of 100 mm × 100 mm and used as measurement samples. A 2% sodium hydroxide solution (pH 13.7) was dropped onto the measurement sample, and after 10 minutes, the sodium hydroxide solution was wiped off, the moisture permeability was measured, and the following criteria were evaluated.
^{^{○: 1.0 × 10 -1 g /}} m 2 / 24hr less ^{^{×: 1.0 × 10 -1 g /}} m 2 / 24hr or more

<Example 1>
(Production of laminated barrier film)
A commercially available COP film (trade name “Zeonor”, manufactured by Nippon Zeon Co., Ltd., thickness 40 μm) is used as a base material, and a sputtering target containing Al, SiO ₂ and ZnO is used to form the first on the base material by DC magnetron sputtering. An oxide layer (thickness 30 nm) was formed. Next, a second oxide layer (50 nm) was formed on the first oxide layer of the base material / first oxide layer stack using a Si target. In this way, a laminated barrier film having a configuration of base material / first oxide layer (AZO) / second oxide layer (SiO ₂ ) was produced. The surface of the substrate to be sputtered was previously roughened by corona treatment. The surface roughness Ra of the surface was 0.51 nm.

(Production of polarizer)
At the same time, a long roll of polyvinyl alcohol (PVA) resin film (product name “PE3000”, manufactured by Kuraray Co., Ltd.) having a thickness of 30 μm is uniaxially stretched in the longitudinal direction so as to be 5.9 times in the longitudinal direction by a roll stretching machine. Swelling, dyeing, crosslinking, and washing treatment were performed, and finally a drying treatment was performed to produce a polarizer having a thickness of 12 μm.
Specifically, the swelling treatment was stretched 2.2 times while being treated with pure water at 20 ° C. Next, the dyeing treatment is performed in an aqueous solution at 30 ° C. in which the weight ratio of iodine and potassium iodide is 1: 7, the iodine concentration of which is adjusted so that the single transmittance of the obtained polarizer is 45.0%. The film was stretched 1.4 times. Furthermore, the crosslinking treatment employed a two-stage crosslinking treatment, and the first-stage crosslinking treatment was stretched 1.2 times while being treated in an aqueous solution in which boric acid and potassium iodide were dissolved at 40 ° C. The boric acid content of the aqueous solution of the first-stage crosslinking treatment was 5.0% by weight, and the potassium iodide content was 3.0% by weight. The cross-linking treatment at the second stage was stretched 1.6 times while being treated in an aqueous solution in which boric acid and potassium iodide were dissolved at 65 ° C. The boric acid content of the aqueous solution of the second crosslinking treatment was 4.3% by weight, and the potassium iodide content was 5.0% by weight. In addition, the cleaning treatment was performed with an aqueous potassium iodide solution at 20 ° C. The potassium iodide content of the aqueous solution for the washing treatment was 2.6% by weight. Finally, the drying process was performed at 70 ° C. for 5 minutes to obtain a polarizer.

(Preparation of polarizing plate)
An HC-TAC film (thickness 32 μm) having a hard coat (HC) layer formed on one side of the TAC film by a hard coat treatment on one side of the polarizer via a polyvinyl alcohol adhesive on the other side In addition, a normal TAC film (thickness 25 μm) was bonded to each other with a roll-to-roll through a polyvinyl alcohol-based adhesive to obtain a long polarizing plate having a protective layer / polarizer / protective layer configuration.

(Production of optical laminate)
The HC-TAC surface of the polarizing plate obtained above and the base material surface of the laminated barrier film obtained above are bonded together by roll-to-roll through an acrylic adhesive, and protective layer / polarizer / protective layer A long optical laminate having a structure of / base material / first oxide layer / second oxide layer was obtained. The obtained optical laminate was subjected to the evaluations (3) to (5) above. The results are shown in Table 1.

<Example 2>
An optical laminate was produced in the same manner as in Example 1 except that the surface roughness Ra of the surface on the first oxide layer side of the substrate was 0.66 nm. The obtained optical laminate was subjected to the same evaluation as in Example 1. The results are shown in Table 1.

<Example 3>
An optical laminate was produced in the same manner as in Example 1 except that the surface roughness Ra of the surface on the first oxide layer side of the substrate was 0.85 nm. The obtained optical laminate was subjected to the same evaluation as in Example 1. The results are shown in Table 1.

<Comparative Example 1>
An optical laminate was produced in the same manner as in Example 1 except that the surface roughness Ra of the surface on the first oxide layer side of the substrate was 0.20 nm. The obtained optical laminate was subjected to the same evaluation as in Example 1. The results are shown in Table 1.

<Comparative Example 2>
An optical laminate was produced in the same manner as in Example 1 except that the surface roughness Ra of the surface on the first oxide layer side of the substrate was 0.28 nm. The obtained optical laminate was subjected to the same evaluation as in Example 1. The results are shown in Table 1.

<Evaluation>
As is clear from Table 1, in the optical laminate having the barrier layer (the first oxide layer and the second oxide layer), the base material, and the polarizer, the first oxide layer side of the base material By setting the surface roughness to a predetermined value or more, reliability can be remarkably improved while maintaining excellent barrier properties and chemical resistance. More specifically, cracks due to the heat shrinkage of the polarizer can be remarkably suppressed.

The optical layered body of the present invention can be suitably used as an optical member having the functions of both a barrier layer (barrier film) and a polarizing plate of an image display device. More specifically, the optical laminate of the present invention can be used as an optical member of a liquid crystal display device and an organic EL display device, preferably an organic EL display device, more preferably a bendable organic EL display device.

DESCRIPTION OF SYMBOLS 10 Base material 20 1st oxide layer 30 2nd oxide layer 40 Polarizing plate 41 Polarizer 42 Protective layer 43 Protective layer 100 Optical laminated body

Claims

Having a polarizer, a base material, a first oxide layer containing ZnO, Al and SiO 2 , and a second oxide layer composed of SiO 2 in this order;
The surface roughness Ra of the surface of the substrate on the first oxide layer side is 0.30 nm to 50 nm.
Optical laminate.
The optical laminate according to claim 1, further comprising a protective layer on at least one side of the polarizer.
The optical laminate according to claim 1 or 2, wherein the thickness of the first oxide layer is 10 nm to 100 nm.
The optical laminate according to any one of claims 1 to 3, wherein the thickness of the second oxide layer is 10 nm to 100 nm.
Moisture permeability is 3.0 × 10 -2 g / m 2 / 24hr or less, the optical laminate according to any one of claims 1 to 4.
Gas barrier property is 1.0 × 10 -7 g / m 2 /24hr~0.5g/m 2 / 24hr, optical laminate according to claim 5.
Moisture permeability after dropping hydrochloric acid or sodium hydroxide solution is less than 1.0 × 10 -1 g / m 2 / 24hr, optical laminate according to any one of claims 1 to 6.