JP2017132224A - Laminated film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laminated film having excellent moisture permeability and gas barrier properties and having excellent chemical resistance, transparency, flexibility and extremely excellent heat resistance.SOLUTION: There is provided a laminated film which comprises a first hard coat layer, a substrate, a second hard coat layer, a first oxide layer containing ZnO, Al and SiOand a second oxide layer made of SiOin this order. In one embodiment, in the laminated film, the shrinkage after heating at 95°C for 1000 hours is 0.5% or less and the moisture permeability after heating at 95°C for 1000 hours is 3.0×10g/m/24hr or less.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a laminated film. More specifically, the present invention relates to a laminated film having two oxide layers on a substrate sandwiched between hard coat layers.

Conventionally, barrier films have been used for image display devices (for example, liquid crystal display devices, organic electroluminescence (EL) display devices) and solar cells (for example, film-type solar cells, thin-film solar cells). 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), and further improvement in transparency is desired. In addition, the barrier film usually has a base material that supports the transparent oxide film. In a heating environment, cracks may occur in the transparent oxide film due to shrinkage of the base material, and the barrier property of the barrier film may be impaired. is there.

JP 2013-189657 A

  The present invention has been made to solve the above-described conventional problems, and the object thereof is excellent moisture permeability and gas barrier property, excellent chemical resistance, transparency and flexibility, and An object of the present invention is to provide a laminated film having extremely excellent heat resistance.

The laminated film of the present invention includes a first hard coat layer, a base material, a second hard coat layer, a first oxide layer containing ZnO, Al and SiO _2, and a first oxide layer composed of SiO ₂ . 2 oxide layers in this order.
In one embodiment, the first hard coat layer further has an anti-blocking function.
In one embodiment, the shrinkage rate after heating the laminated film at 95 ° C. for 1000 hours is 0.5% or less.
In one embodiment, the laminated film is moisture permeability after heating at 95 ° C. 1000 hours ^{3.0 × 10 -2 g / m 2} / 24hr or less.

  According to an embodiment of the present invention, in a laminated film having a substrate, a first oxide layer, and a second oxide layer, such a laminated film is provided by providing hard coat layers on both sides of the substrate. While maintaining the excellent characteristics (moisture permeability, gas barrier property, chemical resistance, transparency and flexibility), it is possible to realize extremely excellent heat resistance.

It is a schematic sectional drawing of the laminated | multilayer film by one Embodiment of this invention.

  Hereinafter, although typical embodiment of this invention is described, this invention is not limited to these embodiment.

A. 1 is a schematic cross-sectional view of a laminated film according to one embodiment of the present invention. The laminated film 100 of the present embodiment includes a first hard coat layer 40, a base material 10, a second hard coat layer 50, a first oxide layer 20, a second oxide layer 30, In this order. That is, according to the embodiment of the present invention, in the laminated film having the base material, the first oxide layer, and the second oxide layer, the base material is the first hard coat layer and the second hard coat layer. Is sandwiched between. With such a configuration, the dimensional change of the base material due to heat (typically, thermal contraction of the base material) can be satisfactorily suppressed. As a result, it is possible to satisfactorily prevent cracks in the first and / or second oxide layers due to the shrinkage of the base material in the heating environment, and as a result, the barrier property of the laminated film is improved even in the heating environment. Can be maintained. Therefore, while maintaining the excellent properties (moisture permeability, gas barrier property, chemical resistance, transparency and flexibility) of the laminated film having the substrate, the first oxide layer and the second oxide layer, Excellent heat resistance can be achieved.

  The thickness of the first hard coat layer 40 is preferably 0.3 μm to 5 μm. The thickness of the second hard coat layer 50 is preferably 0.3 μm to 5 μm. Typically, at least one of the first hard coat layer 40 and the second hard coat layer 50 further has an anti-blocking function. For example, the first hard coat layer 40 may be a hard coat layer further having an anti-blocking function, and the second hard coat layer 50 may be a normal hard coat layer.

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.

The laminated film has a barrier property against moisture and gas (for example, oxygen). 40 ° C. of the laminated film, water vapor transmission rate of 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, the lower limit of the moisture permeability is, for example, 0 from the viewpoint of releasing outgas generated from the device composition over time (for example, acetic acid generated by hydrolysis of solar cell sealing resin (EVA)). .1 × a ^{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., gas barrier properties 90% RH conditions of the laminated film 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. If the moisture permeability and gas barrier properties are in such ranges, when the laminated film is bonded to an object (for example, an image display device or a solar cell), the object is well protected from moisture and oxygen in the air. Can do. Both moisture permeability and gas barrier properties can be measured according to JIS K7126-1.

  The laminate film has a shrinkage ratio after heating at 95 ° C. for 1000 hours of preferably 0.5% or less, more preferably 0.2% or less, and further preferably 0.1% or less. By adopting a configuration in which the base material is sandwiched between two hard coat layers, it is possible to realize such a very excellent heat shrinkage rate during heating. The heat shrinkage rate can be measured according to JIS K 7133.

Laminate film is preferably moisture permeability after heating at 95 ° C. 1000 hours is not more than ^{3.0 × 10 -2 g / m 2} / 24hr, more preferably ^{2.0 × 10 -2 g / m 2} / 24hr hereinafter, still preferably not more than ^{1.0 × 10 -2 g / m 2} / 24hr. By adopting a configuration in which the base material is sandwiched between two hard coat layers, the heat shrinkage of the base material is suppressed, and therefore the heat shrinkage during heating of the entire laminated film is very excellent as described above (very Small). As a result, it is possible to satisfactorily prevent cracks in the first and / or second oxide layers due to shrinkage of the base material in the heating environment, and to realize such moisture permeability after heating. Incidentally, the laminated film is preferably 500 hours at 95 ° C., such as more preferably 600 hours, more preferably less than moisture permeability be heated 700 hours ^{1.0 × 10 -1 g / m 2} / 24hr Has heat resistance.

The laminated film preferably has a total light transmittance of visible light (for example, light having a wavelength of 550 nm) of 84% or more, more preferably 87% or more, and further preferably 90% or more. According to the present invention, a laminated structure of a first oxide layer containing ZnO, Al and SiO ₂ (hereinafter sometimes referred to as an AZO film) and a second oxide layer composed of SiO ₂ is employed. By doing so, the transparency can be increased as compared with the configuration of the AZO film alone, although the thickness is larger than that of the AZO film alone. As a result, since the laminated film does not impair visibility, it can be used very suitably as a barrier film for an image display device.

The laminated film preferably has chemical resistance. More specifically, the laminated film preferably has acid resistance and alkali resistance. In this specification, “acid resistance” means that a 2% hydrochloric acid solution (pH 0.3) is dropped on the laminated film, 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. “Alkali resistance” means that 2% sodium hydroxide solution (pH 13.7) is dropped on the laminated film, and the moisture permeability after wiping off the sodium hydroxide solution after 10 minutes is 1.0 × 10 ^−1. It refers to less than 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 laminated film preferably has a flexibility such that cracking and cracking do not occur even when it is bent with a radius of curvature of 7 mm, more preferably with a radius of curvature 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).

  In one embodiment, the laminated film of the present invention is elongated. The long laminated film can be stored and / or transported by being wound into a roll, for example. Since the laminated film is excellent in flexibility, no problem occurs even if it is wound into a roll.

  Hereinafter, the components of the laminated film will be described.

B. 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. If it is such a structure, when a laminated film is applied to an image display apparatus, the bad influence with respect to the display characteristic of the said image display apparatus can be prevented. 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 an 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, the fast phase). (Nz direction), and “nz” is the refractive index in the thickness direction.

  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.

  The heat shrinkage rate after heating the substrate at 150 ° C. for 90 minutes is preferably 0.01% to 1%, more preferably 0.2% to 0.5%.

  Any appropriate material capable of satisfying the above characteristics can be used as the material constituting the substrate. 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.

  In another embodiment, the base material may have a predetermined phase difference. For example, the substrate may have an in-plane retardation that can function as a so-called λ / 4 plate. With such a configuration, since a good circular polarization function is imparted to the laminated film without separately arranging a retardation layer, the laminated film can be used not only as a barrier film of an image display device but also as an antireflection film. Can work well. In this case, the angle formed by the slow axis of the substrate and the absorption axis of the polarizer used in the image display device 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, more preferably 20 μm to 35 μm or less.

C. First Hard Coat Layer The first hard coat layer 40 is typically formed from an active energy ray curable resin. Examples of active energy rays include ultraviolet rays, visible rays, heat, and electron beams. Preferably, an ultraviolet curable resin can be used. Any appropriate resin can be used as the ultraviolet curable resin. Specific examples include polyester resins, acrylic resins, urethane resins, amide resins, silicone resins, and epoxy resins. The ultraviolet curable resin includes an ultraviolet curable monomer, oligomer, and polymer. Typical examples of the ultraviolet curable resin include a polymer obtained by addition reaction of acrylic acid to a glycidyl acrylate polymer, or a polyfunctional acrylate polymer (such as pentaerythritol and dipentaerythritol). The ultraviolet curable resin (ultraviolet curable resin composition) may preferably further contain a polymerization initiator (typically, a photopolymerization initiator).

  As described above, the thickness of the first hard coat layer is preferably 0.3 μm to 5 μm, more preferably 0.8 μm to 3 μm, and further preferably 1 μm to 2 μm.

  The glass transition temperature of the first hard coat layer is preferably 100 ° C to 200 ° C, more preferably 110 ° C to 180 ° C. Within such a range, a laminated film (barrier film) having excellent heat resistance and excellent dimensional stability at high temperatures can be obtained.

  The first hard coat layer has a pencil hardness in JIS K5600-5-4 of preferably 3H or more and 6H or less. When the first hard coat layer is in this range, the substrate can be prevented from being scratched, and the oxide layer subsequently laminated can be well protected.

  In an embodiment in which the first hard coat layer further has an anti-blocking function, the first hard coat layer further includes fine particles dispersed in the layer. The fine particles may be organic fine particles, inorganic fine particles, or organic-inorganic hybrid fine particles. The microparticles can be composed of, for example, acrylic polymer, silicone polymer, styrene polymer, or inorganic silica. Any appropriate shape can be adopted as the shape of the fine particles. Specific examples include a spherical shape, an elliptical spherical shape, a scale shape, and an indefinite shape. The size of the fine particles is larger than the thickness of the first hard coat layer. As a result, convex portions are formed at positions where the fine particles are present, and a good anti-blocking function can be imparted. The size of the fine particles is the diameter when the fine particles are spherical, and the height (the length in the thickness direction of the first hard coat layer) when the fine particles are not spherical. The size of the fine particles is preferably 1 μm to 5 μm, more preferably 1.5 μm to 3.5 μm. The size of the fine particles is preferably the mode particle size (particle size showing the maximum value of the particle size distribution). The content of the fine particles is preferably 0.05% by weight to 3% by weight of the total weight of the first hard coat layer. If it is such a range, crimping | compression-bonding can be prevented favorably.

In the embodiment in which the first hard coat layer further has an anti-blocking function, the distribution density of the convex portions in the first hard coat layer is preferably 100 pieces / mm ^{2 to} 2000 pieces / mm ² , more preferably. Is 100 / mm ^{2 to} 1000 / mm ² . Within such a range, a good anti-blocking function can be realized.

  In the embodiment in which the first hard coat layer further has an anti-blocking function, the arithmetic average roughness Ra of the surface of the first hard coat layer is preferably 0.005 μm to 0.05 μm. The maximum height Rz of the surface of the first hard coat layer is preferably 0.5 μm to 2.5 μm. If the arithmetic average roughness and the maximum height are within such ranges, a good anti-blocking function can be realized.

  A refractive index adjustment layer (index matching (IM) layer) may be formed on the surface of the first hard coat layer opposite to the substrate. As the IM layer, a well-known configuration in the industry can be adopted, and a detailed description thereof will be omitted.

D. Second Hard Coat Layer The second hard coat layer mainly has a function of not transmitting heat shrinkage of the base material to the first oxide layer and the second oxide layer.

  The glass transition temperature of the second hard coat layer is preferably 95 ° C to 200 ° C, more preferably 110 ° C to 180 ° C. Within such a range, the thermal contraction of the substrate is difficult to be transmitted to the first oxide layer and the second oxide layer, so that the barrier property can be maintained well even in a heating environment.

  The tensile elastic modulus at 25 ° C. of the second hard coat layer is preferably 2.5 GPa to 20 GPa, more preferably 3 GPa to 15 GPa, and further preferably 3.5 GPa to 10 GPa. When the tensile modulus of the hard coat layer is within such a range, a laminate having excellent dimensional stability can be obtained. The tensile elastic modulus can be measured according to JIS K7161.

The linear thermal expansion coefficient at 50 ° C. to 250 ° C. of the second hard coat layer is preferably 0 / ° C. to 100 × 10 ⁻⁶ / ° C., more preferably 0 / ° C. to 50 × 10 ⁻⁶ / ° C. is there. When the linear thermal expansion coefficient of the hard coat layer is within such a range, a laminate having excellent dimensional stability at high temperatures can be obtained. In addition, it is preferable that the linear expansion coefficient of a hard-coat layer is higher than the linear expansion coefficient of a base material.

  The water absorption rate of the second hard coat layer is preferably 0% to 1%, more preferably 0% to 0.5%. When the water absorption rate of the hard coat layer is within such a range, a laminate having excellent dimensional stability under high humidity can be obtained. The water absorption rate can be measured according to JIS K7209.

  Regarding the material, thickness and characteristics of the second hard coat layer, and the configuration in the case of having an anti-blocking function, those having the above characteristics from those described in the section C with respect to the first hard coat layer. It can be selected appropriately.

  The details of the hard coat layer are described in, for example, Japanese Patent No. 5230788. The description of that patent is incorporated herein by reference.

E. 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 wt% to 3.5 wt% and SiO ₂ preferably in a proportion of 20.0 wt% to 62.4 wt% 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.

  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.

F. 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 laminated film are remarkably improved while maintaining good characteristics of the first oxide layer. Can be improved. Furthermore, since the second oxide layer can function as a low refractive index layer, good antireflection characteristics can be imparted to the laminated film.

  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.

G. Use of laminated film The laminated film of the present invention can be suitably used as, for example, a barrier layer (barrier film) for image display devices, electronic paper, and solar cells. More specifically, the laminated film of the present invention has a barrier layer (barrier layer) such as a liquid crystal display device, an organic EL display device, an organic light emitting display device, an electrophoretic display device, a toner display device, a film type solar cell, and a thin film solar cell. Film). The laminated film of the present invention is preferably used as a barrier layer (barrier film) of an organic EL display device, more preferably a bendable organic EL display device.

  EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited by 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 the base material was measured using a film thickness meter (Digital Dial Gauge DG-205 manufactured by Peacock).
(2) Moisture permeability The laminated films obtained in the examples and comparative examples were cut into a 10 cmφ circular shape and used as measurement samples. About this measurement sample, moisture permeability was measured on 40 degreeC and 90% RH test conditions using "DELTATAPERM" by Technolox.
(3) Thermal contraction rate The laminated films obtained in Examples and Comparative Examples were cut into a size of 100 mm × 100 mm and used as measurement samples. This measurement sample was stored in an oven at 95 ° C. for 1000 hours, the dimensions of the measurement sample before and after storage were measured, and the thermal shrinkage rate was calculated from the following equation.
Thermal contraction rate (%) = {(Dimension before storage−Dimension after storage) / (Dimension before storage)} × 100
(4) Heat resistance The laminated films obtained in Examples and Comparative Examples were cut into a size of 100 mm × 100 mm and used as measurement samples. This measurement sample was stored in an oven at 95 ° C. for 1000 hours, the moisture permeability after storage was measured, and evaluated according to the following criteria.
○: moisture permeability is ^{1.0 × 10 -2 g / m 2} / 24hr or less ×: moisture permeability is more than ^{1.0 × 10 -2 g / m 2} / 24hr

<Example 1>
A cycloolefin polymer long film (manufactured by Zeon Corporation, trade name “ZEONOR” (registered trademark), thickness 100 μm, in-plane retardation 10 nm) was used as a substrate. This film was stretched to produce a λ / 4 plate having an in-plane retardation of 140 nm. On one side of the stretched film, an ultraviolet curable resin (polyfunctional polyacrylate manufactured by DIC, product name “UNIDIC”) and fine particles (cross-linked acrylic / styrene resin fine particles manufactured by Sekisui Plastics, product name “SSX105”, A hard coat agent containing 3 μm in diameter) was applied, and the coating film was cured by irradiating with ultraviolet rays to form a first hard coat layer having an anti-blocking function. The first hard coat layer had flat portions (thickness 1 μm) and convex portions randomly distributed corresponding to the fine particles. The distribution density of the convex portions was 205 / mm ² . The arithmetic average roughness Ra of the surface of the first hard coat layer was 0.008 μm, and the maximum height Rz was 0.8 μm. Further, a second hard coat layer, which is a normal hard coat layer, was formed on the other surface of the substrate in the same manner as the first hard coat layer except that a hard coat material containing no fine particles was used. . The thickness of the second hard coat layer was 1 μm. Thus, the laminated body (henceforth a base material laminated body) which has the structure of 1st hard-coat layer / base material / 2nd hard-coat layer was produced.

On the other hand, a first oxide layer (thickness 30 nm) was formed on the surface of the second hard coat layer of the base laminate by a DC magnetron sputtering method using a sputtering target containing Al, SiO ₂ and ZnO. Next, the second oxide layer is formed on the first oxide layer of the first hard coat layer / base material / second hard coat layer / first oxide layer laminate using the Si target. (50 nm) was formed. In this way, a laminated film having a configuration of the first hard coat layer / base material / second hard coat layer / first oxide layer (AZO) / second oxide layer (SiO ₂ ) is produced. did. The obtained laminated film was subjected to the evaluations (2) to (4) above. The results are shown in Table 1.

<Example 2>
A commercially available PET long film (trade name “Diafoil”, thickness: 100 μm) was used as the base material, and the first hard coat layer was a normal hard coat layer (thickness: 0.3 μm). A laminated film was produced in the same manner as in Example 1 except that. The obtained laminated film was subjected to the same evaluation as in Example 1. The results are shown in Table 1.

<Comparative Example 1>
Except that neither the first hard coat layer nor the second hard coat layer was formed, the structure of the substrate / first oxide layer / second oxide layer was the same as in Example 1. The laminated film which has was produced. The obtained laminated film was subjected to the same evaluation as in Example 1. The results are shown in Table 1.

<Comparative example 2>
Except that neither the first hard coat layer nor the second hard coat layer was formed, the structure of the substrate / first oxide layer / second oxide layer was the same as in Example 2. The laminated film which has was produced. The obtained laminated film was subjected to the same evaluation as in Example 1. The results are shown in Table 1.

<Evaluation>
As is clear from Table 1, it can be seen that the heat shrinkage rate and the heat resistance (after 1000 hours) are remarkably improved by providing hard coat layers on both sides of the substrate. In addition, it was actually confirmed that the laminated film having the substrate, the first oxide layer, and the second oxide layer has excellent moisture permeability, gas barrier properties, chemical resistance, transparency, and flexibility. . Therefore, according to the embodiment of the present invention, by providing the hard coat layer on both sides of the base material, the excellent characteristics of the laminated film having the base material, the first oxide layer, and the second oxide layer can be obtained. While maintaining, extremely excellent heat shrinkage rate and heat resistance can be realized.

  The laminated film of the present invention can be suitably used as, for example, a barrier layer (barrier film) for image display devices, electronic paper, and solar cells. More specifically, the laminated film of the present invention has a barrier layer (barrier layer) such as a liquid crystal display device, an organic EL display device, an organic light emitting display device, an electrophoretic display device, a toner display device, a film type solar cell, and a thin film solar cell. Film). The laminated film of the present invention is preferably used as a barrier layer (barrier film) of 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 1st hard-coat layer 50 2nd hard-coat layer 100 Laminated | multilayer film

Claims (4)

A first hard coat layer, a substrate, a second hard coat layer, a first oxide layer containing ZnO, Al and SiO ₂ ; a second oxide layer composed of SiO ₂ ; A laminated film having the above in this order.   The laminated film according to claim 1, wherein the first hard coat layer further has an anti-blocking function.   The laminated film according to claim 1 or 2, wherein the shrinkage after heating at 95 ° C for 1000 hours is 0.5% or less. Moisture permeability after heating at 95 ° C. 1000 hours is not more than ^{3.0 × 10 -2 g / m 2} / 24hr, laminated film according to any one of claims 1 to 3.

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