JP2021092786A - Optical laminate and method for producing the same, polarizing plate, and organic el display device - Google Patents

Abstract

To provide an optical laminate which can effectively suppress permeation of ultraviolet rays even when thickness is thin.SOLUTION: An optical laminate has a first outside layer, a second outside layer and an intermediate layer provided between the first outside layer and the second outside layer. The intermediate layer is formed of a resin (A) containing an ultraviolet absorber, the first outside layer is formed of a resin (B) containing no ultraviolet absorber, the second outside layer is formed of a resin (B') containing no ultraviolet absorber, light transmittance at a wavelength of 390 nm of the optical laminate is 1% or less, a thickness of the optical laminate is 20 μm or more and 47 μm or less, and the optical laminate has other features.SELECTED DRAWING: Figure 1

Description

The present invention relates to an optical laminate, a method for producing the same, and a polarizing plate and an organic EL display device including the optical laminate.

The image display device may be provided with an optical film having an ability to block ultraviolet rays in order to protect the components of the device from ultraviolet rays. Such an optical film is generally made of a resin containing an ultraviolet absorber. Therefore, this optical film has an ability to absorb ultraviolet rays incident on the film, and as a result, has an ability to weaken the ultraviolet rays transmitted through the film (see Patent Documents 1 to 5).
Further, techniques such as Patent Documents 6 and 7 are known.

Japanese Unexamined Patent Publication No. 2011-203400 Japanese Unexamined Patent Publication No. 2015-031753 Japanese Unexamined Patent Publication No. 2015-045845 Japanese Unexamined Patent Publication No. 2004-227843 Japanese Unexamined Patent Publication No. 2000-169767 Japanese Unexamined Patent Publication No. 2015-791139 Japanese Patent No. 3315476

The organic EL display device (organic electroluminescence display) includes an organic material as the material of the light emitting element. Such organic materials are usually easily degraded by UV light. Further, the thin film transistor (hereinafter referred to as "TFT") used in the organic EL display device is also deteriorated by ultraviolet rays. When the organic material or TFT deteriorates, the brightness of the organic EL display device decreases. Therefore, in order to suppress deterioration of the organic material and TFT contained in the organic EL display device and maintain high brightness of the organic EL display device, it is desired to develop an optical film capable of effectively suppressing the transmission of ultraviolet rays. ..

From the viewpoint of effectively suppressing the transmission of ultraviolet rays, it is conceivable to make the optical film thicker. However, when the optical film is made thicker, the organic EL display device is also made thicker. Therefore, in order to meet the demand for thinning, it is desired to suppress the transmission of ultraviolet rays while thinning the optical film.

The present invention has been devised in view of the above problems, and is an optical laminate capable of effectively suppressing the transmission of ultraviolet rays even if the thickness is thin; and a method for producing the same; It is an object of the present invention to provide a plate and an organic EL display device.

As a result of diligent studies to solve the above problems, the present inventor has found an ultraviolet absorber provided between the first outer layer, the second outer layer, the first outer layer and the second outer layer. The present invention has been completed by finding that an optical laminate including an intermediate layer including an intermediate layer having a small light transmittance at a wavelength of 390 nm can effectively suppress the transmission of ultraviolet rays even if the thickness is small.
That is, the present invention includes the following.

[1] An optical laminate including a first outer layer, a second outer layer, and an intermediate layer provided between the first outer layer and the second outer layer.
The intermediate layer is formed of a resin (A) containing an ultraviolet absorber, and is formed of a resin (A).
The first outer layer is formed of the resin (B) that does not contain the ultraviolet absorber.
The second outer layer is formed of a resin (B') that does not contain the ultraviolet absorber, and is formed of a resin (B').
The light transmittance of the optical laminate at a wavelength of 390 nm is 1% or less, and
An optical laminate having a thickness of 20 μm or more and 50 μm or less.
[2] The absorbance of a solution prepared by dissolving 10 mg of the ultraviolet absorber in 1 L of chloroform at a wavelength of 390 nm is 0.1 or more, and
The optical laminate according to [1], wherein the amount of the ultraviolet absorber in the resin (A) is 10% by mass or more and 20% by mass or less.
[3] The optical laminate according to [1] or [2], wherein the resin (A) contains a polymer containing an alicyclic structure.
[4] The optics according to any one of [1] to [3], wherein the ratio of the thickness of the intermediate layer to the total thickness of the first outer layer and the second outer layer is 1.0 or more. Laminated body.
[5] The optical laminate according to any one of [1] to [4], wherein the in-plane retardation of the optical laminate at a wavelength of 550 nm is 0 nm or more and 15 nm or less.
[6] The optical laminate according to any one of [1] to [4], wherein the in-plane retardation of the optical laminate at a wavelength of 550 nm is 85 nm or more and 150 nm or less.
[7] The value [%] of the light transmittance of the optical laminate at a wavelength of 390 nm is the following formula (1):
XY <0.5% (1)
(In the above formula (1)
X is a value [%] of the light transmittance after irradiating light from a xenon lamp having an irradiance of 60 W / m ^{2 for 500 hours.}
Y is a value [%] of the light transmittance before irradiating the light from the xenon lamp. )
The optical laminate according to any one of [1] to [6], which satisfies the above conditions.
[8] A polarizing plate comprising a polarizing element and the optical laminate according to any one of [1] to [7].
[9] An organic EL display device including a light emitting element, a quarter wave plate, a polarizer, and an optical laminate according to any one of [1] to [7] in this order.
[10] The method for producing an optical laminate according to any one of [1] to [7].
A method for producing an optical laminate, which comprises a step of co-extruding the resin (B), the resin (A), and the resin (B').

According to the present invention, it is possible to realize an optical laminate capable of effectively suppressing the transmission of ultraviolet rays even if the thickness is thin and a method for producing the same; and a polarizing plate and an organic EL display device provided with the optical laminate.

FIG. 1 is a cross-sectional view schematically showing an optical laminate according to an embodiment of the present invention. FIG. 2 is a cross-sectional view schematically showing a polarizing plate according to an embodiment of the present invention. FIG. 3 is a cross-sectional view schematically showing an organic EL display device according to an embodiment of the present invention.

Hereinafter, the present invention will be described in detail with reference to embodiments and examples. However, the present invention is not limited to the embodiments and examples shown below, and can be arbitrarily modified and implemented without departing from the scope of claims of the present invention and the equivalent scope thereof.

In the following description, the in-plane lettering is referred to as the lettering unless otherwise specified. Further, the in-plane retardation Re of a certain film is a value represented by Re = (nx−ny) × d unless otherwise specified. Here, nx represents the refractive index in the direction perpendicular to the thickness direction of the film (in-plane direction) and in the direction giving the maximum refractive index. ny represents the refractive index in the in-plane direction of the film and perpendicular to the nx direction. d represents the thickness of the film. The measurement wavelength is 550 nm unless otherwise specified.

In the following description, the slow-phase axis of the film represents the in-plane slow-phase axis of the film unless otherwise specified.

In the following description, the "quarter wave plate" and the "polarizing plate" include not only rigid members but also flexible members such as resin films, unless otherwise specified.

In the following description, the "long" film means a film having a length of usually 5 times or more, preferably 10 times or more with respect to the width, and specifically, it is wound into a roll and stored. Or a film having a length that can be transported. There is no particular limitation on the upper limit of the length, but it is usually 100,000 times or less with respect to the width.

In the following description, "ultraviolet light" refers to light having a wavelength of 10 nm to 400 nm unless otherwise specified.

In the following description, the angles formed by the optical axes (polarization absorption axis, polarization transmission axis, slow phase axis, etc.) of each film in a member including a plurality of films are viewed from the thickness direction unless otherwise specified. Represents the angle of time.

[1. Overview of optical laminate]
FIG. 1 is a cross-sectional view schematically showing an optical laminate 100 according to an embodiment of the present invention.
As shown in FIG. 1, the optical laminate 100 includes a first outer layer 110, a second outer layer 120, and an intermediate layer 130 provided between the first outer layer 110 and the second outer layer 120. To be equipped with. Therefore, the optical laminate 100 includes the first outer layer 110, the intermediate layer 130, and the second outer layer 120 in this order. Normally, the first outer layer 110 and the intermediate layer 130 are in direct contact with each other without interposing another layer, and the intermediate layer 130 and the second outer layer 120 are in direct contact with each other without interposing another layer. It is in direct contact.

The intermediate layer 130 is formed of a resin (A) containing an ultraviolet absorber. Therefore, the optical laminate 100 can suppress the transmission of ultraviolet rays. In particular, the optical laminate 100 suppresses the transmission of ultraviolet rays having a wavelength of 390 nm, which has not been noticed in the past, thereby realizing more effective suppression of the transmission of ultraviolet rays than before. Therefore, when the optical laminate 100 is provided in the organic EL display device, deterioration of the organic material contained in the organic EL display device due to ultraviolet rays can be effectively suppressed, so that the life of the organic EL display device can be expected to be extended. ..

Further, the first outer layer 110 is formed of the resin (B) that does not contain the above-mentioned ultraviolet absorber. Further, the second outer layer 120 is formed of the above-mentioned ultraviolet absorber-free resin (B'). Therefore, the first outer layer 110 and the second outer layer 120 are provided on both sides of the intermediate layer 130 containing the ultraviolet absorber. Therefore, the bleed-out of the ultraviolet absorber contained in the intermediate layer 130 can be suppressed. Therefore, since the concentration of the ultraviolet absorber in the intermediate layer 130 can be increased and the range of selection of the type of the ultraviolet absorber can be widened, it is possible to enhance the ability to suppress the transmission of ultraviolet rays even if the thickness of the optical laminate is thin. Is.

[2. Middle layer]
The intermediate layer is formed of a resin (A) containing an ultraviolet absorber. The resin (A) is usually a thermoplastic resin. Therefore, the resin (A) usually contains a thermoplastic polymer and an ultraviolet absorber.

Examples of the polymer include polyolefins such as polyethylene and polypropylene; polyesters such as polyethylene terephthalate and polybutylene terephthalate; polyarylene sulfide such as polyphenylene sulfide; polyvinyl alcohol; polycarbonate; polyarylate; cellulose ester polymer, polyethersulfone; polysulfone. Polyarylsulfone; polyvinyl chloride; polymers containing an alicyclic structure such as norbornene-based polymers; rod-shaped liquid crystal polymers and the like. As the polymer, one type may be used alone, or two or more types may be used in combination at an arbitrary ratio. Further, the polymer may be a homopolymer or a copolymer. Among these, a polymer containing an alicyclic structure is preferable because it is excellent in mechanical properties, heat resistance, transparency, low hygroscopicity, dimensional stability and light weight.

A polymer containing an alicyclic structure is a polymer in which the structural unit of the polymer contains an alicyclic structure. A polymer containing an alicyclic structure usually has excellent moisture and heat resistance. Therefore, by using a polymer containing an alicyclic structure, the moisture and heat resistance of the optical laminate can be improved.

The polymer containing an alicyclic structure may have an alicyclic structure in the main chain or an alicyclic structure in the side chain. Among them, a polymer having an alicyclic structure in the main chain is preferable from the viewpoint of mechanical strength and heat resistance.

Examples of the alicyclic structure include a saturated alicyclic hydrocarbon (cycloalkane) structure and an unsaturated alicyclic hydrocarbon (cycloalkene, cycloalkyne) structure. Among them, a cycloalkane structure and a cycloalkene structure are preferable from the viewpoint of mechanical strength and heat resistance, and a cycloalkane structure is particularly preferable.

The number of carbon atoms constituting the alicyclic structure is preferably 4 or more, more preferably 5 or more, preferably 30 or less, more preferably 20 or less, particularly preferably 20 or less, per alicyclic structure. Is in the range of 15 or less. By setting the number of carbon atoms constituting the alicyclic structure in this range, the mechanical strength, heat resistance and moldability of the resin containing the polymer containing the alicyclic structure are highly balanced.

In the polymer containing an alicyclic structure, the ratio of structural units having an alicyclic structure can be appropriately selected according to the purpose of use. The proportion of the structural unit having an alicyclic structure in the polymer containing an alicyclic structure is preferably 55% by mass or more, more preferably 70% by mass or more, and particularly preferably 90% by mass or more. When the ratio of the structural units having the alicyclic structure in the polymer containing the alicyclic structure is in this range, the transparency and heat resistance of the resin containing the polymer containing the alicyclic structure are improved.

Examples of the polymer containing an alicyclic structure include norbornene-based polymers, monocyclic cyclic olefin-based polymers, cyclic conjugated diene-based polymers, vinyl alicyclic hydrocarbon polymers, and hydrides thereof. Can be mentioned. Among these, norbornene-based polymers are more preferable because they have good transparency and moldability.

Examples of the norbornene-based polymer include a ring-opening polymer of a monomer having a norbornene structure and a hydrogenated product thereof; an addition polymer of a monomer having a norbornene structure and a hydrogenated product thereof. Examples of ring-opening polymers of monomers having a norbornene structure include a ring-opening copolymer of one type of monomer having a norbornene structure and ring-opening of two or more types of monomers having a norbornene structure. Examples thereof include a copolymer and a ring-opening copolymer of a monomer having a norbornene structure and an arbitrary monomer copolymerizable therewith. Further, as an example of the addition polymer of the monomer having a norbornene structure, the addition homopolymer of one kind of monomer having a norbornene structure and the addition copolymer of two or more kinds of monomers having a norbornene structure , And an addition copolymer of a monomer having a norbornene structure and an arbitrary monomer copolymerizable therewith. Among these, a hydrogenated compound of a monomeric ring-opening polymer having a norbornene structure is particularly suitable from the viewpoints of moldability, heat resistance, low hygroscopicity, dimensional stability and light weight.

Examples of the monomer having a norbornene structure include bicyclo [2.2.1] hept-2-ene (trivial name: norbornene) and tricyclo [4.3.0.1 ^2,5 ] deca-3,7. -Diene (trivial name: dicyclopentadiene), 7,8-benzotricyclo [4.3.0.1 ^2,5 ] deca-3-ene (trivial name: methanotetrahydrofluorene), tetracyclo [4.4. 0.1 ^{2, 5} . ^{17, 10} ] Dodeca-3-ene (common name: tetracyclododecene), derivatives of these compounds (for example, those having a substituent on the ring) and the like can be mentioned. Here, examples of the substituent include an alkyl group, an alkylene group, a polar group and the like. A plurality of these substituents may be attached to the ring, the same or different from each other. As the monomer having a norbornene structure, one type may be used alone, or two or more types may be used in combination at an arbitrary ratio.

Examples of the type of polar group include a hetero atom or an atomic group having a hetero atom. Examples of the hetero atom include an oxygen atom, a nitrogen atom, a sulfur atom, a silicon atom, a halogen atom and the like. Specific examples of the polar group include a carboxyl group, a carbonyloxycarbonyl group, an epoxy group, a hydroxyl group, an oxy group, an ester group, a silanol group, a silyl group, an amino group, a nitrile group and a sulfonic acid group.

Examples of the monomer capable of ring-opening copolymerization with the monomer having a norbornene structure include monocyclic olefins such as cyclohexene, cycloheptene and cyclooctene and derivatives thereof; cyclic conjugated diene such as cyclohexene and cycloheptadiene and The derivative; and the like. As the monomer having a norbornene structure and the monomer capable of ring-opening copolymerization, one type may be used alone, or two or more types may be used in combination at an arbitrary ratio.

A ring-opening polymer of a monomer having a norbornene structure can be produced, for example, by polymerizing or copolymerizing the monomer in the presence of a ring-opening polymerization catalyst.

Examples of the monomer that can be additionally copolymerized with the monomer having a norbornene structure include α-olefins having 2 to 20 carbon atoms such as ethylene, propylene and 1-butene and derivatives thereof; cyclobutene, cyclopentene and cyclohexene. Cycloolefins and derivatives thereof; non-conjugated diene such as 1,4-hexadiene, 4-methyl-1,4-hexadiene, 5-methyl-1,4-hexadiene; and the like. Among these, α-olefins are preferable, and ethylene is more preferable. Further, as the monomer having a norbornene structure and the monomer capable of addition copolymerization, one type may be used alone, or two or more types may be used in combination at an arbitrary ratio.

A monomer addition polymer having a norbornene structure can be produced, for example, by polymerizing or copolymerizing the monomer in the presence of an addition polymerization catalyst.

The hydrogenated additives of the ring-opening polymer and the addition polymer described above are, for example, carbon-carbon in the solution of the ring-opening polymer and the addition polymer in the presence of a hydrogenation catalyst containing a transition metal such as nickel and palladium. Unsaturated bonds can be produced, preferably by hydrogenating 90% or more.

Among the norbornene-based polymers, as structural units, X: bicyclo [3.3.0] octane-2,4-diyl-ethylene structure and Y: tricyclo [4.3.0.1 ^2,5 ] decane- It has a 7,9-diyl-ethylene structure, and the amount of these structural units is 90% by mass or more with respect to the total structural units of the norbornene-based polymer, and the ratio of X and the ratio of Y The ratio is preferably 100: 0 to 40:60 in terms of mass ratio of X: Y. By using such a polymer, the layer containing the norbornene-based polymer can be made to have no dimensional change in a long period of time and have excellent stability of optical characteristics.

The weight average molecular weight (Mw) of the polymer contained in the resin (A) is preferably 10,000 or more, more preferably 15,000 or more, particularly preferably 20,000 or more, and preferably 100,000 or less. It is more preferably 80,000 or less, and particularly preferably 50,000 or less. When the weight average molecular weight is in such a range, the mechanical strength and moldability of the layer containing this polymer are highly balanced.

The molecular weight distribution (Mw / Mn) of the polymer contained in the resin (A) is preferably 1.2 or more, more preferably 1.5 or more, particularly preferably 1.8 or more, and preferably 3.5 or less. , More preferably 3.0 or less, and particularly preferably 2.7 or less. Here, Mn represents a number average molecular weight. By setting the molecular weight distribution to the lower limit of the above range or more, the productivity of the polymer can be increased and the production cost can be suppressed. Further, when the value is set to the upper limit or less, the amount of the low molecular weight component becomes small, so that the relaxation at the time of high temperature exposure can be suppressed and the stability of the layer containing the polymer can be enhanced.

The weight average molecular weight (Mw) and the number average molecular weight (Mn) are determined by gel permeation chromatography using cyclohexane as a solvent (however, toluene may be used if the sample is insoluble in cyclohexane). , Polyisoprene or polystyrene equivalent weight average molecular weight.

The glass transition temperature of the polymer contained in the resin (A) is preferably 100 ° C. or higher, more preferably 110 ° C. or higher, particularly preferably 120 ° C. or higher, preferably 160 ° C. or lower, more preferably 150 ° C. or lower. Especially preferably, it is 140 ° C. or lower. When the glass transition temperature of the polymer is at least the lower limit of the above range, the durability of the optical laminate in a high temperature environment can be enhanced, and when it is at least the upper limit of the above range, the optical laminate is stretched. Can be easily done.

The refractive index of the polymer contained in the resin (A) is preferably 1.45 or more, more preferably 1.48 or more, particularly preferably 1.50 or more, preferably 1.60 or less, and more preferably 1. It is .58 or less, particularly preferably 1.54 or less. When the refractive index of the polymer is within the above range, it becomes easy to reduce the difference in the refractive index between the optical laminate and the polarizer when the optical laminate is used as the polarizer protective film, and the polarizing plate The transmittance of the light can be increased.

The saturated water absorption rate of the polymer contained in the resin (A) is preferably 0.03% by mass or less, more preferably 0.02% by mass or less, and particularly preferably 0.01% by mass or less. When the saturated water absorption rate is within the above range, changes in optical properties such as retardation of the layer containing this polymer with time can be reduced. Further, when the optical laminate is used as the polarizer protective film, deterioration of the polarizing plate and the image display device can be suppressed, and the display of the image display device can be kept stable and good for a long period of time.

The saturated water absorption rate is a value obtained by immersing a sample in water at a constant temperature for a certain period of time and expressing the increased mass as a percentage of the mass of the test piece before immersion. Usually, it is measured by immersing it in water at 23 ° C. for 24 hours. The saturated water absorption rate of the polymer can be adjusted to the above range, for example, by reducing the amount of polar groups in the polymer. Therefore, from the viewpoint of lowering the saturated water absorption rate, it is preferable that the polymer contained in the resin (A) does not have a polar group.

The amount of the polymer in the resin (A) is preferably 80% by mass or more, more preferably 82% by mass or more, particularly preferably 84% by mass or more, preferably 90% by mass or less, and more preferably 88% by mass or less. , Particularly preferably 86% by mass or less. By keeping the amount of the polymer within the above range, the moisture and heat resistance of the optical laminate can be effectively improved. Therefore, when the optical laminate is used as the polarizer protective film, the durability of the polarizing plate under humidified conditions can be improved.

The ultraviolet absorber is a component having an ability to absorb ultraviolet rays, and is a component not contained in the resin (B) and the resin (B'). Further, as the ultraviolet absorber, an optical laminate having a light transmittance at a wavelength of 390 nm within a predetermined range of 1% or less is used. Usually, an organic compound is used as such an ultraviolet absorber. Hereinafter, the ultraviolet absorber as an organic compound may be referred to as an "organic ultraviolet absorber". By using an organic ultraviolet absorber, it is usually possible to increase the light transmittance of the optical laminate at a visible wavelength and reduce the haze of the optical laminate. Therefore, the display performance of the image display device including the optical laminate can be improved.

Examples of the organic UV absorber include triazine-based UV absorber, benzophenone-based UV absorber, benzotriazole-based UV absorber, acrylonitrile-based UV absorber, salicylate-based UV absorber, cyanoacrylate-based UV absorber, and azomethine-based UV absorber. Examples thereof include an absorber, an indol-based ultraviolet absorber, a naphthalimide-based ultraviolet absorber, and a phthalocyanine-based ultraviolet absorber.

As the triazine-based ultraviolet absorber, for example, a compound having a 1,3,5-triazine ring is preferable. Specific examples of the triazine-based UV absorber include 2- (4,6-diphenyl-1,3,5-triazine-2-yl) -5-[(hexyl) oxy] -phenol and 2,4-bis. (2-Hydroxy-4-butoxyphenyl) -6- (2,4-dibutoxyphenyl) -1,3,5-triazine and the like can be mentioned. Examples of commercially available products of such triazine-based ultraviolet absorbers include "Chinubin 1577" manufactured by Ciba Speciality Chemicals, "LA-F70" and "LA-46" manufactured by ADEKA.

Examples of the benzotriazole-based ultraviolet absorber include 2,2'-methylenebis [4- (1,1,3,3-tetramethylbutyl) -6- (2H-benzotriazole-2-yl) phenol], 2 -(3,5-di-tert-butyl-2-hydroxyphenyl) -5-chlorobenzotriazole, 2- (2H-benzotriazole-2-yl) -p-cresol, 2- (2H-benzotriazole-2) -Il) -4,6-bis (1-methyl-1-phenylethyl) phenol, 2-benzotriazole-2-yl-4,6-di-tert-butylphenol, 2- [5-chloro (2H)- Benzotriazole-2-yl] -4-methyl-6- (tert-butyl) phenol, 2- (2H-benzotriazole-2-yl) -4,6-di-tert-butylphenol, 2- (2H-benzo Triazole-2-yl) -4- (1,1,3,3-tetramethylbutyl) phenol, 2- (2H-benzotriazole-2-yl) -4-methyl-6- (3,4,5,5) Reaction product of 6-tetrahydrophthalimidylmethyl) phenol, methyl 3- (3- (2H-benzotriazole-2-yl) -5-tert-butyl-4-hydroxyphenyl) propionate / polyethylene glycol 300, 2- Examples thereof include (2H-benzotriazole-2-yl) -6- (linear and side chain dodecyl) -4-methylphenol. Examples of commercially available products of such triazole-based ultraviolet absorbers include "ADEKA STAB LA-31" manufactured by ADEKA and "TINUVIN 326" manufactured by Ciba Speciality Chemicals.

Examples of the azomethine-based ultraviolet absorber include the materials described in Japanese Patent No. 3366697, and examples of commercially available products include "BONASORB UA-3701" manufactured by Orient Chemical Co., Ltd.

Examples of the indole-based ultraviolet absorber include the materials described in Japanese Patent No. 2846091, and examples of commercially available products include "BONASORB UA-3911" and "BONASORB UA-3912" manufactured by Orient Chemical Co., Ltd. And so on.

Examples of the phthalocyanine-based ultraviolet absorber include the materials described in Japanese Patent No. 4403257 and Japanese Patent No. 3286905, and examples of commercially available products include "FDB001" and "FDB002" manufactured by Yamada Chemical Co., Ltd. "And so on.

Among these, as the ultraviolet absorber, an ultraviolet absorber whose absorbance at a wavelength of 390 nm of a sample solution prepared by dissolving 10 mg of an ultraviolet absorber in 1 L of chloroform is preferable. Specifically, the absorbance is preferably 0.1 or more, more preferably 0.11 or more, and particularly preferably 0.12 or more. By using such an ultraviolet absorber, the light transmittance of the optical laminate at a wavelength of 390 nm can be effectively reduced. The upper limit of the absorbance is not particularly limited, but is preferably 0.16 or less, more preferably 0.15 or less, and particularly preferably 0, because it is easy to increase the light transmittance at the visible wavelength of the optical laminate. It is .14 or less.

The absorbance of the sample solution at a wavelength of 390 nm can be measured under the measurement conditions of a temperature of 25 ° C. and an optical path length of 10 mm in the sample solution.

Particularly preferable UV absorbers are "LA-F70" manufactured by ASDEKA, which is a triazine-based UV absorber, Oriental Chemical Industry "UA-3701", which is an azomethine-based UV absorber, and a benzotriazole-based UV absorber. Examples include "Tinuvin 326" manufactured by BASF. Since these are particularly excellent in the ultraviolet absorbing ability in the vicinity of the wavelength of 390 nm, the light transmittance of the optical laminate at the wavelength of 390 nm can be particularly lowered even if the amount is small.

As the ultraviolet absorber, one type may be used alone, or two or more types may be used in combination at an arbitrary ratio.

The amount of the ultraviolet absorber in the resin (A) is preferably 10% by mass or more, more preferably 12% by mass or more, particularly preferably 14% by mass or more, preferably 20% by mass or less, and more preferably 18% by mass. Hereinafter, it is particularly preferably 16% by mass or less. When the amount of the ultraviolet absorber is not less than the lower limit of the above range, the optical laminate can effectively suppress the transmission of ultraviolet rays. Further, when the amount of ultraviolet rays is not more than the upper limit value in the above range, it is easy to increase the light transmittance at the visible wavelength of the optical laminate. Further, since the gelation of the resin (A) due to the ultraviolet absorber can be suppressed during the production of the optical laminate, it is easy to suppress the occurrence of fish eyes in the optical laminate. Here, the fisheye refers to a foreign substance that can be generated inside the optical laminate.

The resin (A) may further contain any component in combination with the polymer and the UV absorber. Optional components include, for example, colorants such as pigments and dyes; plasticizers; fluorescent whitening agents; dispersants; heat stabilizers; light stabilizers; antistatic agents; antioxidants; surfactants and the like. Can be mentioned. One of these may be used alone, or two or more of them may be used in combination at any ratio.

The absolute value of the photoelastic modulus of the resin (A) is preferably 10 × 10 ^-12 Pa ^-1 or less, more preferably 7 × 10 ^-12 Pa ^-1 or less, and particularly preferably 4 × 10 ^-12 Pa ^-1 or less. Is. When the absolute value of the photoelastic coefficient of the resin (A) is within the above range, a high-performance optical laminate can be easily manufactured. Further, when the optical laminate is a stretched film, the variation in the in-plane retardation Re can be reduced.
Here, the photoelastic coefficient C is a value represented by C = Δn / σ, where Δn is the birefringence and σ is the stress.

The method for producing the resin (A) is arbitrary, and can be produced, for example, by mixing a polymer, an ultraviolet absorber, and if necessary, any component. Usually, the resin (A) is produced by kneading the polymer and the ultraviolet absorber at a temperature at which the polymer can be melted. For kneading, for example, a twin-screw extruder can be used.

The thickness of the intermediate layer is preferably set so that the ratio of the thickness of the intermediate layer to the total thickness of the first outer layer and the second outer layer falls within a predetermined range. Therefore, in the optical laminate 100 shown in FIG. 1, for example, the ratio of the thickness _{T 130} of the intermediate layer 130 to the total _T 110 _{+ T 120} thickness _{T 120} of thickness _{T 110} and the second outer layer 120 of the first outer layer 110 " It is preferable that "T ₁₃₀ / (T ₁₁₀ + T ₁₂₀ )" falls within a predetermined range. Specifically, the thickness ratio is preferably 1.0 or more, more preferably 1.3 or more, and particularly preferably 1.5 or more. When the thickness ratio is at least the above lower limit value, the transmission of ultraviolet rays can be effectively suppressed by the optical laminate. The upper limit of the thickness ratio is not particularly limited, but is preferably 3.5 or less, more preferably 3.3 or less, and particularly preferably 3.0 or less. When the thickness ratio is not more than the upper limit value, the first outer layer and the second outer layer can be made thicker, so that the bleed-out of the ultraviolet absorber can be stably suppressed and the optical laminate can be easily manufactured. You can do it.

The thickness of layers such as the intermediate layer, the first outer layer, and the second outer layer contained in the optical laminate can be measured by the following method.
A sample piece is prepared by embedding the optical laminate with an epoxy resin. This sample piece is sliced to a thickness of 0.05 μm using a microtome. After that, the thickness of each layer contained in the optical laminate can be measured by observing the cross section appearing by slicing with a microscope.

Further, when the optical laminate includes only the intermediate layer, the first outer layer and the second outer layer, and it is known in advance that the thickness of the first outer layer and the thickness of the second outer layer are the same. , The thickness of each layer may be measured by the following method.
The thickness of the intermediate layer is calculated from the light transmittance of the optical laminate at a wavelength of 390 nm. Then, the thickness of the first outer layer and the second outer layer can be obtained by subtracting the thickness of the intermediate layer from the total thickness of the optical laminate and dividing by 2.

[3. First outer layer]
The first outer layer is formed of a resin (B) that does not contain an ultraviolet absorber. The resin (B) is usually a thermoplastic resin. Therefore, the resin (B) usually contains a thermoplastic polymer.

As the polymer contained in the resin (B), any polymer selected from the range described as the polymer contained in the resin (A) can be used. Thereby, the same advantages as described in the description of the polymer of the resin (A) can be obtained. Above all, as the polymer contained in the resin (B), it is preferable to use the same polymer as the polymer contained in the resin (A). As a result, it is easy to increase the adhesive strength between the intermediate layer and the first outer layer, and to suppress the reflection of light at the interface between the intermediate layer and the first outer layer.

The amount of the polymer in the resin (B) is preferably 90.0% by mass to 100% by mass, more preferably 95.0% by mass to 100% by mass. By setting the amount of the polymer in the above range, the moist heat resistance and mechanical strength of the optical laminate can be effectively increased.

The resin (B) may further contain any component in combination with the polymer. As the arbitrary component, for example, the same components as those mentioned as the arbitrary component that can be contained in the resin (A) can be mentioned. One of these may be used alone, or two or more of them may be used in combination at any ratio.

The absolute value of the photoelastic coefficient of the resin (B) can be any value selected from the range described in the description of the absolute value of the photoelastic coefficient of the resin (A). This gives the same advantages as described in the description of the photoelastic modulus of the resin (A). Above all, the photoelastic coefficient of the resin (B) is preferably the same as the photoelastic coefficient of the resin (A).

The thickness of the first outer layer is preferably 3 μm or more, more preferably 5 μm or more, particularly preferably 7 μm or more, preferably 15 μm or less, more preferably 13 μm or less, and particularly preferably 10 μm or less. When the thickness of the first outer layer is at least the lower limit of the above range, the bleed-out of the ultraviolet absorber contained in the intermediate layer can be effectively suppressed. Further, when the thickness of the first outer layer is not more than the upper limit value of the above range, the intermediate layer becomes thicker, so that the ability of the optical laminate for suppressing the transmission of ultraviolet rays can be easily enhanced.

[4. Second outer layer]
The second outer layer is formed of a resin (B') that does not contain an ultraviolet absorber. As the resin (B'), any resin selected from the range of resins described as the resin (B) can be used. Therefore, the components and properties of the resin (B') can be selected and applied from the range described as the components and properties of the resin (B). Thereby, the same advantages as described in the description of the resin (B) of the first outer layer can be obtained.

The resin (B') may be a resin different from the resin (B), or may be the same resin as the resin (B). Above all, it is preferable to use the same resin as the resin (B) and the resin (B'). By using the same resin as the resin (B) and the resin (B'), it is possible to suppress the manufacturing cost of the optical laminate and suppress the curl of the optical laminate.

The thickness of the second outer layer can be any thickness selected from the range described as the range of thickness of the first outer layer. Thereby, the same advantages as described in the description of the thickness of the first outer layer can be obtained. Above all, in order to suppress the curl of the optical laminate, it is preferable that the thickness of the second outer layer is the same as that of the first outer layer.

[5. Any layer]
The optical laminate may optionally include any layer in combination with the intermediate layer, first outer layer and second outer layer described above. For example, between the intermediate layer and the first outer layer, between the intermediate layer and the second outer layer, the side opposite to the intermediate layer of the first outer layer, the side opposite to the intermediate layer of the second outer layer, and the like. Any resin layer may be provided at the position. Examples of the optional resin layer include a hard coat layer, a low refractive index layer, an antistatic layer, an index matching layer, and the like.
However, from the viewpoint of thinning the optical laminate, the optical laminate is preferably a film having a three-layer structure without any layer.

[6. Thickness of optical laminate]
The thickness of the optical laminate is usually 20 μm or more, preferably 23 μm or more, and more preferably 25 μm or more. When the thickness of the optical laminate is larger than the above lower limit value, the light transmittance of the optical laminate at a wavelength of 390 nm can be lowered. The thickness of the optical laminate is usually 50 μm or less, preferably 45 μm or less, and more preferably 40 μm or less. When the thickness of the optical laminate is not more than the above upper limit value, the weight and space of the optical laminate can be reduced. Even if the thickness is thin as described above, it is possible to effectively suppress the transmission of ultraviolet rays, thereby effectively protecting components that are susceptible to deterioration due to ultraviolet rays (for example, organic materials of organic EL display devices). This is one of the advantages of the optical laminate.

[7. Characteristics of optical laminate]
The light transmittance of the optical laminate at a wavelength of 390 nm is usually 1% or less, preferably 0.5% or less, more preferably 0.2% or less, and ideally 0%. In this way, by suppressing the transmission of ultraviolet rays in a wavelength range that has not been attracting attention in the past, it is possible to effectively suppress the transmission of ultraviolet rays even if the thickness is thin. Therefore, when this optical laminate is used as a polarizer protective film, it is possible to suppress a decrease in the degree of polarization of the polarizer and suppress coloring of the polarizer. Further, in general, the organic component contained in the organic EL element is particularly liable to be deteriorated by ultraviolet rays having a long wavelength. However, since the optical laminate having a low light transmittance at a wavelength of 390 nm can suppress the deterioration of the organic component contained in the organic EL element due to ultraviolet rays particularly effectively, the life of the organic EL display device can be extended.
For the light transmittance of the optical laminate at a wavelength of 390 nm, for example, the type of the ultraviolet absorber is appropriately selected, the concentration of the ultraviolet absorber in the intermediate layer is adjusted to an appropriate range, or the thickness of the intermediate layer is increased. It can be lowered by doing something like that.

The optical laminate preferably has a high light transmittance at a visible wavelength. Therefore, it is preferable to have a high light transmittance for visible light having a wavelength close to that of ultraviolet rays. For example, the light transmittance of the optical laminate at a wavelength of 430 nm is preferably 80% or more, more preferably 85% or more, particularly preferably 90% or more, and ideally 100%. By having such a high light transmittance, it is possible to suppress unintended coloring of an image when the optical laminate is provided in the image display device.

The value [%] of the light transmittance of the optical laminate at a wavelength of 390 nm preferably satisfies the following formula (1).
XY <0.5% (1)
In the above formula (1), X represents the value [%] of the light transmittance of the optical laminate at a wavelength of 390 nm after irradiation with light from a xenon lamp having an ^{irradiance of 60 W / m 2 for 500 hours.} Further, in the above formula (1), Y represents a value [%] of the light transmittance of the optical laminate at a wavelength of 390 nm before irradiating light from the xenon lamp.

Explaining the formula (1) in more detail, the difference in light transmittance "XY" is preferably less than 0.5%, more preferably 0.3% or less, and particularly preferably 0.1% or less. is there. The fact that the difference in light transmittance "XY" is small as described above indicates that the optical laminate is excellent in light resistance. Therefore, since the difference in light transmittance "XY" is small, the ability of the optical laminate to suppress the transmission of ultraviolet rays can be maintained for a long period of time. The lower limit of the difference in light transmittance "XY" is ideally 0%, but is usually 0.01% or more.

The optical laminate preferably has a low light transmittance at a wavelength of 280 nm to 380 nm. The specific light transmittance of the optical laminate at a wavelength of 280 nm to 380 nm is preferably 1.5% or less, more preferably 1% or less. Thereby, the ability of the optical laminate to block ultraviolet rays can be further enhanced.

The optical laminate preferably has a high total light transmittance from the viewpoint of stably exhibiting the function as an optical member. The specific total light transmittance of the optical laminate is preferably 85% to 100%, more preferably 87% to 100%, and particularly preferably 90% to 100%. The total light transmittance can be measured in the wavelength range of 400 nm to 700 nm using an ultraviolet-visible spectrometer.

The optical laminate preferably has a small haze from the viewpoint of enhancing the image sharpness of the image display device incorporating the optical laminate. The specific haze of the optical laminate is preferably 1% or less, more preferably 0.8% or less, and particularly preferably 0.5% or less. Haze can be measured using a turbidity meter in accordance with JIS K7361-1997.

The optical laminate may be an optically isotropic film having substantially no in-plane retardation Re, and is an optically anisotropic film having an in-plane retardation Re having a size suitable for the application. There may be. For example, when the optical laminate is an optically isotropic film, the specific in-plane retardation of the optical laminate can be preferably 0 nm to 15 nm, more preferably 0 nm to 10 nm, and particularly preferably 0 nm to 5 nm. .. Further, for example, when the optical laminate is an optically anisotropic film capable of functioning as a quarter wave plate, the specific in-plane retardation of the optical laminate is preferably 85 nm or more, more preferably 90 nm or more. It can be particularly preferably 95 nm or more, preferably 150 nm or less, more preferably 140 nm or less, and particularly preferably 120 nm or less.

The direction of the slow axis of the optical laminate is arbitrary. For example, when the optical laminate is a long film, the direction of the slow axis of the optical laminate is such that the orientation angle θ formed by the slow axis with respect to the longitudinal direction of the optical laminate is desired according to the application. It can be set to be an angle. For example, when the optical laminate is an optically anisotropic film capable of functioning as a quarter wave plate, the orientation angle θ is preferably 40 ° or more, more preferably 43 ° or more, and particularly preferably 44 °. The above is preferably 50 ° or less, more preferably 47 ° or less, and particularly preferably 46 ° or less. When a polarizing plate is manufactured using an optical laminate as a polarizer protective film, a long polarizer and a long optical laminate are usually bonded together with their longitudinal directions parallel to each other. Further, the transmission axis of the polarizer is usually parallel or perpendicular to the longitudinal direction of the polarizer. Therefore, when the optical laminate has the orientation angle θ as described above, it is easy to make an angle of 45 ° ± 5 ° between the transmission axis of the polarizer and the slow axis of the optical laminate. Can be pasted together. In the polarizing plate manufactured in this manner, the linearly polarized light transmitted through the polarizer can be converted into circularly polarized light by the optical laminate. Therefore, if this polarizing plate is provided in an image display device that displays an image by linearly polarized light, it is possible to easily realize an image display device that can improve the brightness of the image even when wearing polarized sunglasses.

The amount of the volatile component contained in the optical laminate is preferably 0.1% by mass or less, more preferably 0.05% by mass or less, still more preferably 0.02% by mass or less. When the amount of the volatile component is within the above range, the dimensional stability of the optical laminate can be improved, and the time-dependent change of optical characteristics such as retardation can be reduced. Furthermore, deterioration of the polarizing plate and the image display device including the optical laminate can be suppressed, and the display of the image display device can be kept stable and good for a long period of time. Here, the volatile component is a substance having a molecular weight of 200 or less. Examples of the volatile component include residual monomers and solvents. The amount of the volatile component can be quantified by analyzing by gas chromatography as the total of substances having a molecular weight of 200 or less.

The saturated water absorption rate of the optical laminate is preferably 0.05% or less, more preferably 0.03% or less, particularly preferably 0.01% or less, and ideally 0%. By having such a low saturated water absorption rate of the optical laminate, it is possible to suppress changes in the optical characteristics of the optical laminate over time.

The saturated water absorption rate of the optical laminate can be measured by the following procedure according to JIS K7209.
The optical laminate is dried at 50 ° C. for 24 hours and allowed to cool in a desiccator. Next, the mass (M1) of the dried optical laminate is measured.
The optical laminate is immersed in water for 24 hours in a room at a temperature of 23 ° C. and a relative humidity of 50% to saturate the optical laminate with water. Then, the optical laminate is taken out from water, and the mass (M2) of the optical laminate after immersion for 24 hours is measured.
From the measured values of these masses, the saturated water absorption rate of the optical laminate can be obtained by the following equation.
Saturated water absorption rate (%) = [(M2-M1) / M1] x 100 (%)

[8. Manufacturing method of optical laminate]
There are no restrictions on the manufacturing method of the optical laminate. The optical laminate can be produced, for example, by a production method including a step of molding the resin (B), the resin (A), and the resin (B') into a film. Examples of the molding method of the resin (B), the resin (A) and the resin (B') include a coextrusion method and a cocurrent spreading method. Among these molding methods, the coextrusion method is preferable because it has excellent production efficiency and it is difficult for volatile components to remain in the optical laminate.

The method for producing an optical laminate using the coextrusion method includes a step of coextruding the resin (B), the resin (A), and the resin (B'). In the coextrusion method, the resin (B), the resin (A), and the resin (B') are extruded into layers in a molten state, respectively, to form a first outer layer, an intermediate layer, and a second outer layer. At this time, examples of the resin extrusion method include a coextrusion T-die method, a coextrusion inflation method, and a coextrusion lamination method. Above all, the coextrusion T-die method is preferable. The coextrusion T-die method includes a feed block method and a multi-manifold method, and the multi-manifold method is particularly preferable in that the variation in thickness can be reduced.

In the coextrusion method, the melting temperature of the extruded resin (B), resin (A) and resin (B') is preferably Tg + 80 ° C. or higher, more preferably Tg + 100 ° C. or higher, preferably Tg + 180 ° C. or lower, more preferably. Is Tg + 150 ° C. or lower. Here, "Tg" represents the highest temperature among the glass transition temperatures of the polymers contained in the resin (B), the resin (A), and the resin (B'). Further, the melting temperature represents, for example, in the coextrusion T-die method, the melting temperature of the resin (B), the resin (A) and the resin (B') in the extruder having the T-die. When the melting temperature of the extruded resin (B), resin (A) and resin (B') is equal to or higher than the lower limit of the above range, the fluidity of the resin can be sufficiently increased and the moldability can be improved. When it is not more than the upper limit value, deterioration of the resin can be suppressed.

The extrusion temperature can be appropriately selected depending on the resin (B), the resin (A) and the resin (B'). For example, the temperature of the resin in the extruder can be Tg to (Tg + 100 ° C.) at the resin inlet, (Tg + 50 ° C.) to (Tg + 170 ° C.) at the extruder outlet, and the die temperature can be (Tg + 50 ° C.) to (Tg + 170 ° C.) ° C. ..

Further, the arithmetic mean roughness Ra of the die slip of the die is preferably 0 μm to 1.0 μm, more preferably 0 μm to 0.7 μm, and particularly preferably 0 μm to 0.5 μm. By keeping the arithmetic mean roughness of the die slip within the above range, it becomes easy to suppress streak-like defects in the optical laminate.

In the coextrusion method, a film-like molten resin extruded from a die slip is usually brought into close contact with a cooling roll to be cooled and cured. At this time, examples of the method of bringing the molten resin into close contact with the cooling roll include an air knife method, a vacuum box method, and an electrostatic close contact method.

By molding the resin (B), the resin (A), and the resin (B') into a film as described above, the first outer layer made of the resin (B) and the intermediate layer made of the resin (A) are formed. An optical laminate including a second outer layer made of resin (B') in this order can be obtained.

Further, the method for producing the optical laminate may include a stretching step. By subjecting the optical laminate obtained by molding the resin as described above to a stretching treatment, the optical laminate can be made to exhibit desired optical characteristics such as retardation. In the following description, the "pre-stretched laminate" refers to an optical laminate before being stretched, and the "stretched laminate" refers to an optical laminate that has been stretched.

The stretching may be performed by a uniaxial stretching treatment in which the stretching treatment is performed in only one direction, or a biaxial stretching treatment in which the stretching treatment is performed in two different directions. Further, in the biaxial stretching treatment, a simultaneous biaxial stretching treatment in which stretching treatments are simultaneously performed in two directions may be performed, and a sequential biaxial stretching treatment in which stretching treatment is performed in one direction and then in another direction. May be done. Further, the stretching may be a longitudinal stretching treatment in which the pre-stretched laminate is stretched in the longitudinal direction, a transverse stretching treatment in which the pre-stretched laminate is stretched in the width direction, or a pre-stretched laminate that is neither parallel nor perpendicular to the width direction. Any of the diagonal stretching treatments in which the stretching treatment is performed in the diagonal direction may be performed, and these may be performed in combination. Among these stretching treatments, the diagonal stretching treatment is preferable.

When a polarizing plate is manufactured using a stretched laminate as a polarizer protective film, it is usually required to bond the stretched laminate so that the transmission axis of the polarizer and the slow axis of the stretched laminate intersect at a predetermined angle. .. However, the direction of the slow axis of the stretched laminate obtained by the longitudinal stretching treatment and the transverse stretching treatment is parallel or perpendicular to the width direction of the stretched laminate. Such a stretched laminate having a slow-phase axis parallel to or perpendicular to the width direction is usually required to be cut into a single sheet in an oblique direction in order to be bonded to a polarizer at a predetermined angle. On the other hand, in the stretched laminate obtained by the oblique stretching treatment, the direction of the slow phase axis is an oblique direction that is neither parallel nor perpendicular to the width direction of the stretched laminate. Therefore, in the stretched laminate obtained by the diagonal stretching treatment, a polarizing plate can be easily manufactured by sticking the stretched laminate with a polarizer by roll-to-roll.

The stretching temperature and stretching ratio can be arbitrarily set according to the optical characteristics desired to be developed by stretching. Specifically, the stretching temperature is preferably Tg-30 ° C. or higher, more preferably Tg-10 ° C. or higher, preferably Tg + 60 ° C. or lower, and more preferably Tg + 50 ° C. or lower. The draw ratio is preferably 1.01 to 30 times, preferably 1.01 to 10 times, and more preferably 1.01 to 5 times.

Further, the method for manufacturing the optical laminate may further include an arbitrary step in addition to the above-mentioned steps.

[9. Polarizer]
The above-mentioned optical laminate can be used in a wide range of applications as an optical film such as a retardation film, a polarizer protective film, and a polarization compensation film. Above all, the optical laminate is preferably used for the polarizer protective film. A polarizing plate using an optical laminate as a polarizer protective film includes a polarizer and an optical laminate.

FIG. 2 is a cross-sectional view schematically showing a polarizing plate 200 according to an embodiment of the present invention.
As shown in FIG. 2, the polarizing plate 200 includes a polarizer 210 and an optical laminate 100 provided on at least one side of the polarizer 210. Such a polarizing plate 200 is excellent in durability because the optical laminate 100 can block ultraviolet rays to protect the polarizer 210.

As the polarizer 210, a film capable of transmitting one of two linearly polarized light intersecting at right angles and absorbing or reflecting the other can be used. Specific examples of the polarizer 210 include a film of a vinyl alcohol-based polymer such as polyvinyl alcohol and partially formalized polyvinyl alcohol, which is dyed, stretched, and crosslinked with a dichroic substance such as iodine or a dichroic dye. Such as those which have been subjected to appropriate processing in an appropriate order and method can be mentioned. In particular, a polarizer 210 containing polyvinyl alcohol is preferable. The thickness of the polarizer 210 is usually 5 μm to 80 μm.

Further, when the optical laminate 100 can function as a quarter wave plate, in the polarizing plate 200, the polarization transmission axis of the polarizer 210 and the slow axis of the optical laminate 100 are 45 ° ± 5 °. It is preferable to make an angle of. As a result, the linearly polarized light transmitted through the polarizer 210 can be converted into circularly polarized light by the optical laminate 100.

The polarizing plate 200 can be manufactured by bonding the optical laminate 100 to the polarizing element 210. An adhesive may be used for bonding, if necessary.

The polarizing plate 200 may further include an arbitrary layer (not shown) in combination with the above-mentioned polarizer 210 and the optical laminate 100. For example, the polarizing plate 200 may include an arbitrary protective film layer (not shown) other than the optical laminate 100 for protection of the polarizer 210. Such a protective film layer is usually provided on the surface of the polarizer 210 on the side opposite to the optical laminate 100. Further, examples of the optional layer include a hard coat layer, a low refractive index layer, an antistatic layer, and an index matching layer.

[Organic EL display device]
FIG. 3 is a cross-sectional view schematically showing an organic EL display device 300 according to an embodiment of the present invention. As shown in FIG. 3, the organic EL display device 300 includes an organic EL element 310 as a light emitting element, a quarter wave plate 320, a polarizer 210, and an optical laminate 100 in this order. As the polarizer 210 and the optical laminate 100, the same ones as those of the above-described embodiment described with reference to FIG. 2 can be used.

The organic EL element 310 includes an electrode layer 311 such as a reflective electrode and a transparent electrode, a transparent electrode layer 312, and a light emitting layer 313 provided between the electrode layer 311 and the transparent electrode layer 312. The light emitting layer 313 can generate light by applying a voltage from the transparent electrode layer 312. Examples of the materials constituting the light emitting layer 313 include polyparaphenylene vinylene-based materials, polyfluorene-based materials, and polyvinyl carbazole-based materials. Further, the light emitting layer 313 may have a laminate of a plurality of layers having different emission colors, or a mixed layer in which a layer of a certain dye is doped with different dyes. Further, even if the organic EL element 310 includes functional layers (not shown) such as a hole injection layer, a hole transport layer, an electron injection layer, an electron transport layer, an equipotential surface forming layer, and a charge generation layer. Good. In the organic EL display device 300, an image is displayed by the light emitted from the organic EL element 310.

The in-plane retardation Re of the 1/4 wave plate 320 is preferably 80 nm or more, more preferably 85 nm or more, particularly preferably 90 nm or more, preferably 180 nm or less, more preferably 160 nm or less, and particularly preferably 150 nm or less. is there. Further, the slow axis of the 1/4 wave plate 320 preferably forms an angle of 45 ° ± 5 ° with respect to the polarization transmission axis of the polarizer 210. As such a 1/4 wave plate 320, a resin film such as a stretched film or a film obtained by curing a liquid crystal composition can be used.

Since such a 1/4 wave plate 320 can convert linearly polarized light transmitted through the polarizer 210 into circularly polarized light, the combination of the 1/4 wave plate 320 and the polarizer 210 realizes a function as a circular polarizing plate. Will be done. Therefore, the quarter wave plate 320 can suppress glare on the display surface due to reflection of external light by combining with the polarizer 210. Specifically, the light incident from the outside of the apparatus becomes circularly polarized light when only a part of the linearly polarized light passes through the polarizer 210 and then passes through the 1/4 wave plate 320. Circularly polarized light is reflected by a component that reflects light in the display device (such as the electrode layer 311 in the organic EL element 310), and passes through the 1/4 wave plate 320 again to vibrate the incident linearly polarized light. It becomes linearly polarized light having a vibration direction orthogonal to and does not pass through the polarizer 210. Thereby, the antireflection function is achieved (for the principle of antireflection in the organic EL display device, refer to Japanese Patent Application Laid-Open No. 9-127885).

Since the organic EL display device 300 includes the optical laminate 100, it is possible to suppress the ingress of ultraviolet rays. Therefore, deterioration of organic components contained in the components of the organic EL display device 300 such as the light emitting layer 313, the 1/4 wave plate 320, and the polarizer 210 due to ultraviolet rays can be suppressed. In particular, in the organic EL display device 300, when the organic component contained in the light emitting layer 313 deteriorates, the brightness tends to decrease. Therefore, being able to suppress deterioration of the organic component contained in the light emitting layer 313 due to ultraviolet rays is effective for extending the life of the organic EL display device 300.

Further, when the optical laminate 100 can function as a 1/4 wave plate, the optical laminate 100 is formed by appropriately adjusting the angle formed by the deflection transmission axis of the polarizer 210 and the slow axis of the optical laminate 100. This makes it possible to improve the visibility of the image when viewed through polarized sunglasses. Normally, in the organic EL display device 300, an image is displayed by light emitted from the organic EL element 310 and passing through the 1/4 wave plate 320, the polarizer 210, and the optical laminate 100. Therefore, the light for displaying an image is linearly polarized light when it passes through the polarizer 210, but is converted to circularly polarized light when it passes through the optical laminate 100. Therefore, in the organic EL display device 300, since the image is displayed by circularly polarized light, the image can be visually recognized when the display surface 300U is viewed through polarized sunglasses.

Hereinafter, the present invention will be specifically described with reference to Examples. However, the present invention is not limited to the examples shown below, and can be arbitrarily modified and implemented without departing from the scope of claims of the present invention and the equivalent scope thereof.
In the following description, "%" and "part" representing quantities are based on mass unless otherwise specified. Further, the operations described below were performed in the air at normal temperature and pressure unless otherwise specified.

In the following description, unless otherwise specified, "DCP" means "tricyclo [4.3.0.1 ^2,5 ] deca-3-ene" and "TCD" means "tetracyclo [4.4. 0.1 ^2,5 .1 ^7,10] dodeca-3-ene "indicates, the" MTF "" tetracyclo ^[9.2.1.0 2,10 ^{.0 3,8]} tetradeca-3,5 , 7,12-Tetraene ”.

[Evaluation method]
(Measurement method of absorbance)
10 mg of UV absorber was mixed with 1 liter of chloroform and dissolved to obtain a sample solution. The absorbance of this sample solution at a measurement wavelength of 390 nm was measured using a measuring device (“V-7200” manufactured by JASCO Corporation) under the conditions of a temperature of 25 ° C. and an optical path length of 10 mm in the sample solution.

(Measuring method of film orientation angle)
The direction of the slow axis of the film was measured using a phase difference meter (“KOBRA-21ADH” manufactured by Oji Measurement Co., Ltd.). The orientation angle θ formed by the slow axis with respect to the longitudinal direction of the film was determined.

(Measuring method of in-plane retardation Re of film)
The in-plane retardation Re of the film was measured at a measurement wavelength of 550 nm using a phase difference meter (“KOBRA-21ADH” manufactured by Oji Measurement Co., Ltd.).

(Measuring method of the thickness of each layer contained in the film)
The thickness of the entire film was measured with a snap gauge.
The thickness of the intermediate layer contained in the film was obtained by measuring the light transmittance of the film at a wavelength of 390 nm using an ultraviolet-visible near-infrared spectrophotometer (“V-7200” manufactured by JASCO Corporation). Calculated from transmittance. Further, in Examples and Comparative Examples described later, since the first outer layer and the second outer layer are formed as layers having the same thickness, the thickness of the first outer layer and the second outer layer is intermediate from the thickness of the entire film. It was calculated by subtracting the thickness of the layer and dividing by two.

(Measurement method of light transmittance before light resistance test)
Prior to the light resistance test described later, the light transmittance of the film at a wavelength of 390 nm was measured using an ultraviolet-visible near-infrared spectrophotometer (“V-7200” manufactured by JASCO Corporation).

(Measurement method of light transmittance after light resistance test)
The film was subjected to a light resistance test in which light was irradiated from a xenon lamp having an irradiance of 60 W / m ^{2 for 500 hours.} Then, the light transmittance of the film irradiated with light at a wavelength of 390 nm was measured using the above-mentioned ultraviolet-visible near-infrared spectrophotometer.

[Manufacturing Example 1: Production of Resin J1]
(Ring-opening polymerization)
To the reactor replaced with nitrogen, 7 parts of a mixture of DCP, TCD and MTF (DCP / TCD / MTF = 55/40/5 mass ratio) and 1600 parts of cyclohexane were added. The amount of the mixture of DCP, TCD and MTF is 1% by mass with respect to the total amount of the monomers used for the polymerization.

Further, 0.55 parts of tri-i-butylaluminum, 0.21 part of isobutyl alcohol, 0.84 part of diisopropyl ether as a reaction modifier, and 3.24 parts of 1-hexene as a molecular weight regulator were added to the reactor. did.
To this, 24.1 parts of a cyclohexane solution of tungsten hexachloride having a concentration of 0.65% was added, and the mixture was stirred at 55 ° C. for 10 minutes.

Next, while maintaining the reaction system at 55 ° C., 693 parts of a mixture of DCP, TCD and MTF (DCP / TCD / MTF = 55/40/5 mass ratio) and a cyclohexane solution of tungsten hexachloride having a concentration of 0.65% 48.9 parts were continuously added dropwise into the system over 150 minutes.

Then, the reaction was continued for 30 minutes to complete the polymerization. As a result, a ring-opening polymerization reaction solution containing a ring-opening polymer in cyclohexane was obtained. After the completion of the polymerization, the polymerization conversion rate of the monomer measured by gas chromatography was 100% at the end of the polymerization.

(Hydrogenation)
The obtained ring-opening polymerization reaction solution was transferred to a pressure-resistant hydrogenation reactor. To this reactor, 1.4 parts of a nickel-supported nickel catalyst (“T8400RL” manufactured by Nikki Kagaku Co., Ltd., nickel-supporting ratio 57%) and 167 parts of cyclohexane were added, and the temperature was 180 ° C. The hydrogenation reaction was carried out. By this hydrogenation reaction, a reaction solution containing a hydrogenated product of a ring-opening polymer was obtained. From this reaction solution, the hydrogenation catalyst is removed by pressure filtration (manufactured by Ishikawajima Harima Heavy Industries, Ltd., product name "Fundafilter") using Radiolite # 500 as a filtration bed at a pressure of 0.25 MPa to obtain a colorless and transparent solution. It was.

Next, 0.5 part of the antioxidant per 100 parts of the hydrogenated agent (pentaerythritol tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate]], manufactured by Ciba Specialty Chemicals, Inc. "Irganox 1010") was added to the resulting solution to dissolve it. Next, this solution is sequentially filtered through a filter (“Zeter Plus Filter 30H” manufactured by Cuno Filter Co., Ltd., pore size 0.5 μm to 1 μm), and further another metal fiber filter (manufactured by Nichidai Corporation, pore diameter 0.4 μm). To remove minute solids from the solution. The hydrogenation rate of the hydrogenated product of the ring-opening polymer was 99.9%.

Next, the solution obtained by the above filtration is treated with a cylindrical concentrating dryer (manufactured by Hitachi, Ltd.) at a temperature of 270 ° C. and a pressure of 1 kPa or less. Volatile components were removed. Then, the solid content contained in the solution was extruded into a strand in a molten state from a die directly connected to the concentrator, and after cooling, pellets of resin J1 containing a hydrogenated additive of a ring-opening polymer were obtained. The weight average molecular weight (Mw) of the hydrogenated product of the ring-opening polymer contained in the pellet was 38,000, the molecular weight distribution (Mw / Mn) was 2.5, and the glass transition temperature Tg was 126 ° C.

[Manufacturing Example 2: Production of Resin J2]
85.0 parts of the dried resin J1 (glass transition temperature 126 ° C.) and 15.0 parts of a triazine-based ultraviolet absorber (“LA-F70” manufactured by ADEKA Corporation) are mixed by a twin-screw extruder to form a mixture. Got Next, the mixture was put into a hopper connected to a single-screw extruder and melt-extruded using the single-screw extruder to obtain resin J2. The amount of the ultraviolet absorber in the resin J2 was 15.0% by mass.

[Manufacturing Example 3: Production of Resin J3]
90.0 parts of the dried resin J1 (glass transition temperature 126 ° C.) and 10.0 parts of a triazine-based ultraviolet absorber ("LA-F70" manufactured by ADEKA Corporation) are mixed by a twin-screw extruder to form a mixture. Got Next, the mixture was put into a hopper connected to a single-screw extruder and melt-extruded using the single-screw extruder to obtain resin J3. The amount of the ultraviolet absorber in the resin J3 was 10.0% by mass.

[Manufacturing Example 4: Production of Resin J4]
93.0 parts of the dried resin J1 (glass transition temperature 126 ° C.) and 7.0 parts of the triazine-based ultraviolet absorber ("LA-F70" manufactured by ADEKA Corporation) are mixed by a twin-screw extruder to form a mixture. Got Next, the mixture was put into a hopper connected to a single-screw extruder and melt-extruded using the single-screw extruder to obtain resin J4. The amount of the ultraviolet absorber in the resin J4 was 7.0% by mass.

[Manufacturing Example 5: Production of Resin J5]
93.0 parts of the dried resin J1 (glass transition temperature 126 ° C.) and 7.0 parts of a benzotriazole-based ultraviolet absorber (“LA-31” manufactured by ADEKA Corporation) were mixed by a twin-screw extruder. A mixture was obtained. Next, the mixture was put into a hopper connected to a single-screw extruder and melt-extruded using the single-screw extruder to obtain resin J5. The amount of the ultraviolet absorber in the resin J5 was 7.0% by mass.

[Manufacturing Example 6: Production of Resin J6]
89.0 parts of the dried resin J1 (glass transition temperature 126 ° C.) and 11.0 parts of a benzotriazole-based ultraviolet absorber (“LA-31” manufactured by ADEKA Corporation) were mixed by a twin-screw extruder. A mixture was obtained. Next, the mixture was put into a hopper connected to a single-screw extruder and melt-extruded using the single-screw extruder to obtain resin J6. The amount of the ultraviolet absorber in the resin J6 was 11.0% by mass.

[Manufacturing Example 7: Manufacture of Resin J7]
97.0 parts of the dried resin J1 (glass transition temperature 126 ° C.) and 3.0 parts of an indole-based ultraviolet absorber (“UA-3911” manufactured by Orient Chemical Industry Co., Ltd.) are mixed by a twin-screw extruder. , A mixture was obtained. Next, the mixture was put into a hopper connected to a single-screw extruder and melt-extruded using the single-screw extruder to obtain resin J7. The amount of the ultraviolet absorber in the resin J7 was 3.0% by mass.

[Example 1]
A double-flight single-screw extruder (screw diameter D50 mm, effective screw length L to screw diameter D ratio L / D = 28) equipped with a leaf disk-shaped polymer filter having a mesh opening of 3 μm was prepared. The resin J2 obtained in Production Example 2 was put into a hopper connected to this single-screw extruder and melted under the condition of an extruder outlet temperature of 260 ° C. The molten resin J2 was supplied to a single-layer die having a die slip surface roughness Ra of 0.1 μm via a feed block.

On the other hand, one single-screw extruder (screw diameter D = 50 mm, effective screw length L to screw diameter D ratio L / D = 30) equipped with a leaf disk-shaped polymer filter with a mesh opening of 3 μm is prepared. did. The resin J1 obtained in Production Example 1 was introduced into this single-screw extruder and melted under the condition of an extruder outlet temperature of 260 ° C. The molten resin J1 was supplied to the single-layer die via a feed block.

Next, the molten resin J1 and the resin J2 are discharged from the single-layer die at 280 ° C. so as to be discharged in the form of a film including the resin J1 layer, the resin J2 layer, and the resin J1 layer. I let you. The discharged resin is cast on a cooling roll whose temperature has been adjusted to 100 ° C., and the first outer layer made of resin J1 (thickness 5 μm) -intermediate layer made of resin J2 (thickness 20 μm) -second made of resin J1. A laminate having three layers of an outer layer (thickness 5 μm) was obtained. When casting the discharged resin onto the cooling roll, the air gap amount was set to 50 mm. Further, edge pinning was adopted as a method of casting the molten film-like resin onto the cooling roll.

The width of the obtained laminate was 1450 mm and the thickness was 30 μm. Both ends of this laminated body were trimmed by 50 mm to obtain a pre-stretched laminated body 1 as an optical laminated body having a width of 1350 mm. The in-plane retardation Re of the obtained pre-stretched laminate 1, the light transmittance at a wavelength of 390 nm before the light resistance test, and the light transmittance at a wavelength of 390 nm after the light resistance test were measured by the methods described above.

[Example 2]
By adjusting the extrusion conditions of the resin from the single-layer die, the thickness of each layer was changed to the first outer layer (thickness 6 μm), the intermediate layer (33 μm), and the second outer layer (6 μm). Except for the above items, the pre-stretched laminate 2 as the optical laminate 2 was manufactured and evaluated in the same manner as in Example 1.

[Example 3]
(Manufacturing of pre-stretched laminate)
By adjusting the extrusion conditions of the resin from the single-layer die, the thickness of each layer was changed to the first outer layer (thickness 7.5 μm), the intermediate layer (30 μm), and the second outer layer (7.5 μm). Except for the above items, the pre-stretched laminate 3 was produced in the same manner as in Example 1.

(Stretching process)
The pre-stretched laminate 3 was stretched diagonally while being continuously conveyed in the longitudinal direction to obtain a stretched laminate S1 as an optical laminate. The stretching was carried out at a stretching temperature of 138 ° C. and a stretching ratio of 1.5 times using a tenter stretching machine equipped with a gripper capable of gripping the end portion of the pre-stretching laminate 3 in the film width direction. The orientation angle θ of the obtained stretched laminate S1, the in-plane retardation Re, the light transmittance at a wavelength of 390 nm before the light resistance test, and the light transmittance at a wavelength of 390 nm after the light resistance test were measured by the methods described above.

[Example 4]
(Manufacturing of pre-stretched laminate)
As the resin for forming the intermediate layer, resin J3 was used instead of resin J2. Further, by adjusting the extrusion conditions of the resin from the single-layer die, the thickness of each layer is changed to the first outer layer (thickness 11.5 μm), the intermediate layer (47 μm), and the second outer layer (11.5 μm). did. A pre-stretched laminate 4 was manufactured in the same manner as in Example 1 except for the above items.

(Stretching process)
The pre-stretched laminate 4 was used instead of the pre-stretched laminate 3. Moreover, the stretching temperature was changed to 141 ° C. Except for the above items, the stretched laminate S2 was produced and evaluated in the same manner as in the above (stretching step) of Example 3.

[Example 5]
As the resin for forming the intermediate layer, resin J7 was used instead of resin J2. Except for the above items, the pre-stretched laminate 11 as the optical laminate 11 was manufactured and evaluated in the same manner as in Example 1.

[Comparative Example 1]
(Manufacturing of pre-stretched laminate)
As the resin for forming the intermediate layer, resin J5 was used instead of resin J2. Further, by adjusting the extrusion conditions of the resin from the single-layer die, the thickness of each layer is changed to the first outer layer (thickness 16.5 μm), the intermediate layer (37 μm), and the second outer layer (16.5 μm). did. A pre-stretched laminate 5 was manufactured in the same manner as in Example 1 except for the above items.

(Stretching process)
The pre-stretched laminate 5 was used instead of the pre-stretched laminate 3. Moreover, the stretching temperature was changed to 141 ° C. Except for the above items, the stretched laminate S3 was produced and evaluated in the same manner as in the above (stretching step) of Example 3.

[Comparative Example 2]
(Manufacturing of pre-stretched laminate)
As the resin for forming the intermediate layer, resin J6 was used instead of resin J2. Further, by adjusting the extrusion conditions of the resin from the single-layer die, the thickness of each layer was changed to the first outer layer (thickness 9 μm), the intermediate layer (20 μm), and the second outer layer (9 μm). A pre-stretched laminate 6 was produced in the same manner as in Example 1 except for the above items.

(Stretching process)
The pre-stretched laminate 6 was used instead of the pre-stretched laminate 3. Moreover, the stretching temperature was changed to 136 ° C. Except for the above items, the stretched laminate S4 was produced and evaluated in the same manner as in the above (stretching step) of Example 3.

[Comparative Example 3]
As the resin for forming the intermediate layer, resin J5 was used instead of resin J2. Further, by adjusting the extrusion conditions of the resin from the single-layer die, the thickness of each layer can be adjusted to the first outer layer (thickness 8.25 μm), the intermediate layer (8.5 μm), and the second outer layer (8.25 μm). Changed to. Except for the above items, the pre-stretched laminate 7 as an optical laminate 7 was manufactured and evaluated in the same manner as in Example 1.

[Comparative Example 4]
As the resin for forming the intermediate layer, resin J4 was used instead of resin J2. Further, by adjusting the extrusion conditions of the resin from the single-layer die, the thickness of each layer is changed to the first outer layer (thickness 8.5 μm), the intermediate layer (9 μm), and the second outer layer (8.5 μm). did. Except for the above items, the pre-stretched laminate 8 as the optical laminate 8 was manufactured and evaluated in the same manner as in Example 1.

[Comparative Example 5]
As the resin for forming the intermediate layer, resin J4 was used instead of resin J2. Except for the above items, the pre-stretched laminate 9 as an optical laminate 9 was manufactured and evaluated in the same manner as in Example 1.

[Comparative Example 6]
By adjusting the extrusion conditions of the resin from the single-layer die, the thickness of each layer was changed to the first outer layer (thickness 10 μm), the intermediate layer (10 μm), and the second outer layer (10 μm). Except for the above items, the pre-stretched laminate 10 as an optical laminate 10 was manufactured and evaluated in the same manner as in Example 1.

[result]
The results of the above Examples and Comparative Examples are shown in the table below. In the table below, the meanings of the abbreviations are as follows.
UVA concentration: The concentration of the UV absorber in the resin contained in the intermediate layer.
390 nm Absorbance: Absorbance of a sample solution prepared by dissolving 10 mg of an ultraviolet absorber in 1 L of chloroform at a wavelength of 390 nm.
Re: In-plane lettering.
Thickness ratio: The ratio of the thickness of the intermediate layer to the total thickness of the first outer layer and the second outer layer.
Orientation angle θ: The angle formed by the slow axis of the stretched laminate with respect to the longitudinal direction.
Light transmittance (before test): Light transmittance at a wavelength of 390 nm measured before the light resistance test.
Light transmittance (after test): Light transmittance at a wavelength of 390 nm measured after the light resistance test.

[Example 6: Production of circularly polarizing plate]
The surface of the stretched laminate S2 produced in Example 4 was subjected to corona treatment. The corona-treated surface of the stretched laminate S2 and a long polarizing film as a linear polarizing element (“HLC2-5618S” manufactured by Sanritz Co., Ltd., thickness 180 μm, transmission axis in the direction of 0 ° with respect to the width direction). One surface of (having) was bonded to each other via an adhesive (“LE-3000 series” manufactured by Hitachi Chemical Co., Ltd.) to obtain a circularly polarizing plate.

100 Optical laminate 110 First outer layer 120 Second outer layer 130 Intermediate layer 200 Polarizing plate 210 Polarizer 300 Organic EL display device 310 Organic EL element 311 Electrode layer 312 Transparent electrode layer 313 Light emitting layer 320 1/4 wave plate

Claims (9)

An optical laminate comprising a first outer layer, a second outer layer, and an intermediate layer provided between the first outer layer and the second outer layer.
The intermediate layer is formed of a resin (A) containing an ultraviolet absorber, and is formed of a resin (A).
The first outer layer is formed of the resin (B) that does not contain the ultraviolet absorber.
The second outer layer is formed of a resin (B') that does not contain the ultraviolet absorber, and is formed of a resin (B').
The light transmittance of the optical laminate at a wavelength of 390 nm is 1% or less.
The thickness of the optical laminate is 20 μm or more and 47 μm or less.
The absorbance of a solution prepared by dissolving 10 mg of the ultraviolet absorber in 1 L of chloroform at a wavelength of 390 nm is 0.1 or more, and
An optical laminate in which the amount of the ultraviolet absorber in the resin (A) is 12% by mass or more and 20% by mass or less. The optical laminate according to claim 1, wherein the resin (A) contains a polymer containing an alicyclic structure. The optical laminate according to claim 1 or 2, wherein the ratio of the thickness of the intermediate layer to the total thickness of the first outer layer and the second outer layer is 1.0 or more. The optical laminate according to any one of claims 1 to 3, wherein the in-plane retardation of the optical laminate at a wavelength of 550 nm is 0 nm or more and 15 nm or less. The optical laminate according to any one of claims 1 to 3, wherein the in-plane retardation of the optical laminate at a wavelength of 550 nm is 85 nm or more and 150 nm or less. The value [%] of the light transmittance of the optical laminate at a wavelength of 390 nm is the following formula (1):
XY <0.5% (1)
(In the above formula (1)
X is a value [%] of the light transmittance after irradiating light from a xenon lamp having an irradiance of 60 W / m ^{2 for 500 hours.}
Y is a value [%] of the light transmittance before irradiating the light from the xenon lamp. )
The optical laminate according to any one of claims 1 to 5, which satisfies the above conditions. A polarizing plate comprising a polarizer and the optical laminate according to any one of claims 1 to 6. An organic EL display device including a light emitting element, a quarter wave plate, a polarizer, and an optical laminate in this order.
The optical laminate is an optical laminate including a first outer layer, a second outer layer, and an intermediate layer provided between the first outer layer and the second outer layer.
The intermediate layer is formed of a resin (A) containing an ultraviolet absorber, and is formed of a resin (A).
The first outer layer is formed of the resin (B) that does not contain the ultraviolet absorber.
The second outer layer is formed of a resin (B') that does not contain the ultraviolet absorber, and is formed of a resin (B').
The light transmittance of the optical laminate at a wavelength of 390 nm is 1% or less, and
An organic EL display device in which the thickness of the optical laminate is 20 μm or more and 47 μm or less. The method for manufacturing an optical laminate according to any one of claims 1 to 6.
A method for producing an optical laminate, which comprises a step of co-extruding the resin (B), the resin (A), and the resin (B').

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