JP2023067092A - Laminate, laminate with adhesive layer, polarizing film, polarizing film with adhesive layer, and method for manufacturing polarizing film - Google Patents

Abstract

To provide a laminate in which occurrence of surface unevenness of a resin layer caused by an uneven structure of a peelable base material film is suppressed, when the resin layer is peeled from the base material film, a laminate with an adhesive layer, a polarizing film and a polarizing film with an adhesive layer using the same, and a method for manufacturing a polarizing film.SOLUTION: A laminate has a first resin layer, a second resin layer and a peelable base material film in this order, wherein the first resin layer contains a first resin having storage elastic modulus measured as a film with a thickness of 1 mm of 650 MPa or more and 1,700 MPa or less, and the second resin layer contains a second resin having storage elastic modulus measured as a film with a thickness of 1 mm of 10 MPa or more and less than 650 MPa.SELECTED DRAWING: Figure 1

Description

TECHNICAL FIELD The present invention relates to a laminate, a laminate with an adhesive layer, a polarizing film, a polarizing film with an adhesive layer, and a method for producing a polarizing film.

In display devices such as liquid crystal display devices and organic electroluminescence display devices, polarizing films are sometimes arranged for various purposes. A polarizing film generally has a polarizer layer and a resin layer provided on the surface of the polarizer layer. The resin layer can function as a protective layer for the polarizer layer. As for the polarizer film, the development of techniques for arranging a resin layer on a polarizer layer by a transfer method is underway (Patent Documents 1 and 2).

WO2019/087806 JP 2014-130298 A

In a polarizing film, if the protection of the polarizer layer is insufficient, for example, cracks may occur in the polarizer layer due to temperature changes. What can be done is required.

Moreover, the peelable base film used when forming the protective layer of the polarizer layer using a transfer method may have a fine uneven structure on its surface. An example of the uneven structure is a minute uneven structure called a fish eye. When a resin liquid containing a resin is applied to such a base film and dried to form a resin layer, the uneven structure of the base film may be transferred to the resin layer. When such a resin layer is used as a protective layer of a polarizing film, surface irregularities due to the irregular structure of the base film may occur in the protective layer, and the display quality of a display device using this may be degraded. There is

The present invention has been invented in view of the above problems, and can be used as a resin layer (protective layer) that can suppress cracks in the polarizer layer of a polarizing film, and can be peeled from a base film. Laminate that can alleviate the occurrence of surface unevenness of a resin layer due to the uneven structure of a base film when the layer is peeled off, a laminate with an adhesive layer using the same, a polarizing film, a polarizing film with an adhesive layer, and polarized light It aims at providing the manufacturing method of a film.

The inventors have made extensive studies to solve the above problems. As a result, the present inventor found that in a laminate comprising a first resin layer, a second resin layer and a peelable base film in this order, the storage elastic modulus of the resin contained in the first resin layer and the second resin layer is The inventors have found that the above problems can be solved by adjusting each, and completed the present invention.
That is, the present invention includes the following.

[1] A first resin layer, a second resin layer and a peelable base film are provided in this order, and the first resin layer has a storage modulus of 650 MPa or more and 1700 MPa or less measured as a film having a thickness of 1 mm. A laminate comprising a first resin, wherein the second resin layer contains a second resin having a storage elastic modulus of 10 MPa or more and less than 650 MPa as measured as a film having a thickness of 1 mm.
[2] The laminate according to [1], wherein the thickness of the first resin layer is greater than 0 μm and no greater than 12 μm, and the thickness of the second resin layer is greater than 0 μm and no greater than 12 μm.
[3] The laminate according to [1] or [2], wherein the sum of the thickness of the first resin layer and the thickness of the second resin layer is 12 μm or less.
[4] The first resin and the second resin each independently have a water vapor transmission rate of 4 g/(m ² day) or less at 40° C. and 90% RH measured as a film having a thickness of 100 μm. The laminate according to any one of [1] to [3].
[5] The first resin layer and the second resin layer each independently have an in-plane retardation of 5 nm or less and an absolute retardation value in the thickness direction of 5 nm or less [1] The laminate according to any one of [4].
[6] Any one of [1] to [5], wherein the first resin layer and the second resin layer each independently have a photoelastic constant of 5×10 ⁻¹³ cm ² /dyn or less. The laminate according to item 1.
[7] The laminate according to any one of [1] to [6], wherein the first resin and the second resin each independently contain a polymer having an alicyclic structure.
[8] In the second resin, the polymer having an alicyclic structure is a block copolymer hydride [E], and the block copolymer hydride [E] is a block copolymer [D ], the block copolymer [D] is a block copolymer consisting of a polymer block [A] and a polymer block [B] or a polymer block [C], and the polymer Block [A] is a polymer block mainly composed of repeating unit [I] derived from an aromatic vinyl compound, and polymer block [B] is a repeating unit [I] derived from an aromatic vinyl compound and a chain It is a polymer block whose main component is the repeating unit [II] derived from a conjugated diene compound, and the polymer block [C] is a polymer block whose main component is the repeating unit [II] derived from a chain conjugated diene compound. The laminate according to [7].
[9] At least one of the first resin layer and the second resin layer contains an ultraviolet absorber, and the content of the ultraviolet absorber is 2% by weight or more and 40% by weight or less, [1] to [8] ] The laminated body as described in any one of ].
[10] The laminate according to any one of [1] to [9], wherein the second resin contains a plasticizer and/or a softener.
[11] The laminate according to [10], wherein the plasticizer and/or softener is at least one selected from the group consisting of ester plasticizers and aliphatic hydrocarbon polymers.
[12] The laminate according to any one of [1] to [11], wherein at least one of the first resin and the second resin contains an organometallic compound.
[13] The laminate according to any one of [1] to [12], wherein the peelable base film has a tensile modulus of 2000 MPa or more.
[14] A first resin layer, a second resin layer and an adhesive layer are provided in this order, and the first resin layer contains a first resin having a storage modulus of 650 MPa or more and 1700 MPa or less measured as a film having a thickness of 1 mm. , the second resin layer contains a second resin having a storage modulus of 10 MPa or more and less than 650 MPa measured as a film with a thickness of 1 mm, and the thickness of the adhesive layer is 2 μm or more and 25 μm or less Lamination with an adhesive layer body.
[15] A polarizer layer, a first resin layer and a second resin layer are provided in this order, and the first resin layer has a storage modulus of 650 MPa or more and 1700 MPa or less measured as a film having a thickness of 1 mm. wherein the second resin layer contains a second resin having a storage elastic modulus of 10 MPa or more and less than 650 MPa when measured as a film having a thickness of 1 mm.
[16] The polarizing film of [15], wherein the polarizer layer has a thickness of more than 1 μm and 12 μm or less.
[17] A polarizing film with an adhesive layer, comprising the laminate with an adhesive layer according to [14] and a polarizer layer provided on the first resin layer of the laminate with an adhesive layer.
[18] The method for producing a polarizing film according to [15] or [16], wherein the second resin liquid containing the second resin is applied onto the peelable base film and dried to obtain the second resin A step of forming a layer, a step of applying a first resin liquid containing the first resin on the second resin layer and drying it to form a first resin layer, a polarizer layer and the first resin layer. and a step of peeling the peelable base film from the second resin layer, in this order.

According to the present invention, it can be used as a resin layer capable of suppressing cracking of the polarizer layer of the polarizing film, and when the resin layer is peeled off from the peelable base film, it is caused by the uneven structure of the base film. It is possible to provide a laminate capable of alleviating the occurrence of surface unevenness of a resin layer, a laminate with an adhesive layer using the same, a polarizing film, a polarizing film with an adhesive layer, and a method for producing a polarizing film.

FIG. 1 is a cross-sectional view schematically showing a laminate according to one embodiment of the present invention. FIG. 2 is a cross-sectional view schematically showing a laminate with an adhesive layer according to one embodiment of the present invention. FIG. 3 is a cross-sectional view schematically showing a polarizing film according to one embodiment of the invention. FIG. 4 is a cross-sectional view schematically showing a polarizing film with an adhesive layer according to one embodiment of the present invention.

Hereinafter, the present invention will be described in detail by showing embodiments and examples. However, the present invention is not limited to the embodiments and examples shown below, and can be arbitrarily modified without departing from the scope of the claims of the present invention and their equivalents.

In the following description, "long" refers to a shape having a length that is usually 5 times or more, preferably 10 times or more, than the width, specifically a roll shape A shape that has a length that can be rolled up and stored or transported. Although the upper limit of the ratio of length to width is not particularly limited, it can be, for example, 100,000 times or less.

In the following description, adhesives and pressure-sensitive adhesives are distinguished by their shear storage modulus unless otherwise specified. Specifically, unless otherwise specified, an adhesive indicates a material having a shear storage modulus of 1 MPa to 500 MPa at 23° C. after irradiation with an energy beam or after heat treatment. Further, unless otherwise specified, the pressure-sensitive adhesive refers to a material having a shear storage modulus of less than 1 MPa at 23°C.

In the following description, the in-plane retardation Re of a layer is a value represented by Re=(nx−ny)×d unless otherwise specified. Further, the thickness direction retardation Rth of a certain layer is a value represented by Rth=[{(nx+ny)/2}-nz]×d unless otherwise specified. Here, nx represents the refractive index in the direction (in-plane direction) perpendicular to the thickness direction of the layer, which gives the maximum refractive index. ny represents the refractive index in the in-plane direction of the layer and perpendicular to the nx direction. nz represents the refractive index in the thickness direction of the layer. d represents the thickness of the layer. The measurement wavelength is 550 nm unless otherwise stated.

In the following description, (meth)acrylic resins include acrylic resins, methacrylic resins, and combinations thereof, unless otherwise specified. In addition, (meth)acrylic acid includes acrylic acid, methacrylic acid, and combinations thereof, unless otherwise specified.

In the following description, "plate", "layer" and "film" may be rigid members, unless otherwise specified, or flexible members such as resin films. good too.

[1. Laminate]
FIG. 1 is a cross-sectional view schematically showing a laminate 100 according to one embodiment of the invention. As shown in FIG. 1, the laminate 100 includes a first resin layer 101, a second resin layer 102, and a peelable base film 20 in this order in the thickness direction.

In the laminate 100 , the second resin layer 102 is normally provided directly on the base film 20 . Moreover, in the laminate 100 , the first resin layer 101 is normally provided directly on the second resin layer 102 . Here, another layer is provided “directly” with respect to a certain layer means that the certain layer is in contact with the other layer and there is no other layer between the certain layer and the other layer. indicates that

The first resin layer 101 contains a first resin having a storage modulus of 650 MPa or more and 1700 MPa or less when measured as a film with a thickness of 1 mm. The second resin layer 102 contains a second resin having a storage elastic modulus of 10 MPa or more and less than 650 MPa when measured as a film with a thickness of 1 mm. In the following description, unless otherwise specified, "storage elastic modulus measured as a film having a thickness of 1 mm" may be simply referred to as "storage elastic modulus".

According to the present invention, flexibility can be imparted to the second resin layer by including the second resin having a storage modulus of 10 MPa or more and less than 650 MPa in the second resin layer. Therefore, even if the surface unevenness due to the uneven structure of the base film occurs immediately after the second resin layer is peeled off from the base film, the second resin layer has flexibility and the surface unevenness over time. Since the difference in height between the two can be reduced, the unevenness of the surface of the second resin layer can be alleviated.

In addition, since the first resin layer contains the first resin having a storage elastic modulus of 650 MPa or more and 1700 MPa or less, rigidity can be imparted to the first resin layer. Therefore, when the laminated portion of the first resin layer and the second resin layer is used as a protective layer for the polarizer layer in the polarizing film, cracking of the polarizer layer due to temperature change can be suppressed.

[1.1. First resin layer]
The first resin layer is a layer containing a first resin having a storage modulus of 650 MPa or more and 1700 MPa.

[1.1.1. First resin]
The first resin is a resin having a storage modulus of 650 MPa or more and 1700 MPa measured as a 1 mm film.

The storage modulus of the first resin is usually 650 MPa or more, preferably 700 MPa or more, more preferably 750 MPa or more, and usually 1700 MPa or less, preferably 1000 MPa or less, more preferably 900 MPa or less. Since the storage elastic modulus of the first resin is equal to or higher than the lower limit, cracks in the polarizer layer due to temperature change can be prevented when the laminated portion of the first resin layer and the second resin layer is used as a protective layer in the polarizing film. The storage elastic modulus of the first resin layer is equal to or less than the upper limit value, so that cracks in the polarizer layer are suppressed when used as a protective layer of the polarizing film, and good bending is achieved in the polarizing film. This is because it can give

The storage modulus of the first resin can be measured by the following measuring method.
A film for measurement having a thickness of 1 mm is prepared by molding the first resin. As a molding method, a hot melt press method can be used. After that, the storage elastic modulus of the prepared measurement film is measured using a dynamic viscoelasticity measuring device. This measurement is carried out in a temperature range of -100°C to +250°C at a heating rate of 5°C/min. From the measured results, the storage modulus at 23°C can be read.

The first resin preferably has a water vapor transmission rate at 40° C. and 90% RH measured as a film having a thickness of 100 μm within a predetermined range. Specifically, the water vapor transmission rate of the first resin is preferably 4.0 g/(m ² ·day) or less, more preferably 3.0 g/(m 2 ·day) or less, and particularly preferably 2.0 g/(m ² ·day) or less. It is 0 g/(m ² ·day) or less. The lower limit is ideally 0 g/(m ² ·day), and may be 0.1 g/(m ² ·day) or more. By forming the first resin layer with the first resin having a water vapor transmission rate within the above range, the humidity reliability of the polarizing film using this can be particularly improved. Specifically, since the moisture permeability of the first resin layer can be sufficiently lowered, it is possible to suppress water vapor from reaching the polarizer layer and effectively suppress the deterioration of the degree of polarization due to water vapor.

The water vapor transmission rate of the first resin can be measured by the following measuring method.
A measurement film having a thickness of 100 μm is prepared by molding the first resin. A hot melt press method can be used as a molding method. After that, the water vapor transmission rate of the prepared film for measurement is measured under conditions of a temperature of 40° C. and a humidity of 90% RH. This measurement is performed according to JIS K 7129 B method using a water vapor transmission rate measuring device.

The first resin usually contains a polymer. Moreover, the polymer contained in the first resin usually has thermoplasticity. Since the polymer has thermoplasticity, the first resin can also have thermoplasticity.

Examples of the polymer contained in the first resin include polyesters, acrylic polymers, and polymers containing an alicyclic structure. One type of these polymers may be used alone, or two or more types may be used in combination at an arbitrary ratio. Among them, a polymer containing an alicyclic structure is preferable from the viewpoint of lowering the water vapor transmission rate of the first resin layer.

A polymer containing an alicyclic structure contains an alicyclic structure in the repeating unit of the polymer. Polymers containing alicyclic structures usually have low water vapor transmission rates. Therefore, when the first resin layer is formed of the first resin containing a polymer containing an alicyclic structure, it is possible to effectively prevent water vapor from reaching the polarizer layer.

The polymer containing an alicyclic structure may contain an alicyclic structure in the main chain, may contain an alicyclic structure in the side chain, or may contain an alicyclic structure in both the main chain and the side chain. It may contain a cyclic structure. Among them, from the viewpoint of mechanical strength and heat resistance, a polymer having at least an alicyclic structure in its main chain is preferable.

The alicyclic structure includes, for example, a saturated alicyclic hydrocarbon (cycloalkane) structure, an unsaturated alicyclic hydrocarbon (cycloalkene, cycloalkyne) structure, and the like. Among them, from the viewpoint of mechanical strength and heat resistance, a cycloalkane structure and a cycloalkene structure are preferable, 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, and particularly preferably 4 or more per alicyclic structure. is in the range of 15 or less. When the number of carbon atoms constituting the alicyclic structure is within this range, the mechanical strength, heat resistance and moldability of the first resin are highly balanced.

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

Examples of polymers containing an alicyclic structure include norbornene polymers, monocyclic cyclic olefin polymers, cyclic conjugated diene polymers, vinyl alicyclic hydrocarbon polymers, and hydrides thereof. mentioned. Among these, norbornene-based polymers and their hydrides are preferred because they have good transparency and moldability and are easy to adjust to a desired storage elastic modulus.

Examples of norbornene-based polymers and hydrides thereof include ring-opening polymers of monomers having a norbornene structure and hydrides thereof; addition polymers of monomers having a norbornene structure and hydrides thereof. Examples of ring-opening polymers of monomers having a norbornene structure include ring-opening homopolymers of one type of monomer having a norbornene structure, and ring-opening of two or more types of monomers having a norbornene structure. Copolymers, and ring-opening copolymers of monomers having a norbornene structure and arbitrary monomers copolymerizable therewith. Furthermore, examples of addition polymers of monomers having a norbornene structure include addition homopolymers of one type of monomer having a norbornene structure, and addition copolymers of two or more types of monomers having a norbornene structure. and addition copolymers of monomers having a norbornene structure and arbitrary monomers copolymerizable therewith. Examples of these polymers include those disclosed in JP-A-2002-321302.

Specific examples of the norbornene-based polymer and its hydride include "Zeonor" manufactured by Nippon Zeon; "Arton" manufactured by JSR; and "TOPAS" manufactured by TOPAS ADVANCED POLYMERS.

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

The molecular weight distribution (Mw/Mn) of the polymer contained in the first resin is preferably 1.2 or more, more preferably 1.5 or more, particularly preferably 1.8 or more, preferably 3.5 or less, or more It is preferably 3.0 or less, particularly preferably 2.7 or less. Here, Mn represents the number average molecular weight. When the molecular weight distribution is at least the lower limit of the above range, the productivity of the polymer can be enhanced and the production cost can be suppressed. Further, when the molecular weight distribution is equal to or less than the upper limit of the above range, the amount of low-molecular-weight components is small, so relaxation during high-temperature exposure can be suppressed, and the stability of the first resin layer can be enhanced.

The weight average molecular weight (Mw) and number average molecular weight (Mn) can be measured using gel permeation chromatography (GPC). Solvents used in GPC include cyclohexane, toluene, and tetrahydrofuran. When GPC is used, the weight average molecular weight can be measured, for example, as a relative molecular weight in terms of polyisoprene or polystyrene.

The glass transition temperature of the polymer contained in the first resin is preferably 100° C. or higher, more preferably 110° C. or higher, still more preferably 120° C. or higher, preferably 170° C. or lower, more preferably 160° C. or lower. It is preferably 150° C. or less. When the glass transition temperature of the polymer is within the above range, the durability of the polarizing film in a high-temperature environment can be enhanced. The glass transition temperature can be measured using a differential scanning calorimeter (DSC) by heating at a rate of 10°C/min.

The amount of the polymer contained in the first resin is preferably 70% by weight or more, more preferably 80% by weight or more, still more preferably 85% by weight or more, and usually 99% by weight, based on 100% by weight of the first resin. %, preferably 96% by weight or less, more preferably 93% by weight or less. When the amount of the polymer contained in the first resin is within the above range, cracks in the polarizer layer due to temperature change can be effectively suppressed.

The first resin may further contain optional components in combination with the polymer described above. Optional components include, for example, moisture absorbents; dispersants; organometallic compounds; stabilizers such as antioxidants and light stabilizers; resin modifiers such as lubricants; coloring agents such as dyes and pigments; etc. One of the optional components may be used alone, or two or more of them may be used in combination at any ratio.

The first resin preferably further contains an organometallic compound in combination with the polymer. By including the organometallic compound, the adhesion between the first resin layer and the polarizer layer described below can be enhanced.

An organometallic compound is a compound containing at least one of a chemical bond between a metal and carbon and a chemical bond between a metal and oxygen, and is a metal compound having an organic group. Organic metal compounds include organic silicon compounds, organic titanium compounds, organic aluminum compounds, organic zirconium compounds, and the like. Among these, an organic silicon compound, an organic titanium compound and an organic zirconium compound are preferable, and an organic silicon compound is more preferable because it is excellent in reactivity with components such as polyvinyl alcohol contained in the polarizer layer. The organometallic compounds may be used singly or in combination of two or more at any ratio.

Examples of organometallic compounds include organosilicon compounds represented by the following formula (1).
R ¹ _a Si(OR ² ) _4-a (1)
(In Formula (1), R ¹ and R ² each independently represent a hydrogen atom, a halogen atom, a hydrocarbon group having 1 to 10 carbon atoms, an epoxy group, an amino group, a thiol group, an isocyanate group and a carbon represents a group selected from the group consisting of organic groups having 1 to 10 atoms, and a represents an integer of 0 to 4.)

In formula (1), preferable examples of R ¹ include an epoxy group, an amino group, a thiol group, an isocyanate group, a vinyl group, an acryl group, an alkyl group having 1 to 8 carbon atoms, and the like.
In formula (1), preferred examples of R ² include a hydrogen atom, a vinyl group, an aryl group, an acryl group, an alkyl group having 1 to 8 carbon atoms, —CH ₂ OC _n H _2n+1 (n is 1 represents an integer of up to 4.) and the like.

Examples of organosilicon compounds include epoxy-based organosilicon compounds such as 3-glycidoxypropyltrimethoxysilane and 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane; 3-aminopropyltrimethoxysilane, N- Amino-based organosilicon compounds such as 2-(aminoethyl)-3-aminopropyltrimethoxysilane; isocyanurate-based organosilicon compounds such as tris-(trimethoxysilylpropyl)isocyanurate; 3-mercaptopropyltrimethoxysilane and the like mercapto-based organosilicon compounds; isocyanate-based organosilicon compounds such as 3-isocyanatopropyltriethoxysilane;

Examples of organic titanium compounds include titanium alkoxides such as tetraisopropyl titanate, titanium chelates such as titanium acetylacetonate, and titanium acylates such as titanium isostearate.

Examples of organic zirconium compounds include zirconium alkoxides such as normal propyl zirconate, zirconium chelates such as zirconium tetraacetylacetonate, and zirconium acylates such as zirconium stearate.

Examples of organoaluminum compounds include aluminum alkoxides such as aluminum secondary butoxide and aluminum chelates such as aluminum trisacetylacetonate.

The amount of the organometallic compound is preferably 0.005 parts by weight or more, more preferably 0.01 parts by weight or more, and particularly preferably 0.03 parts by weight or more with respect to 100 parts by weight of the polymer contained in the first resin. , preferably 1.0 parts by weight or less, more preferably 0.5 parts by weight or less. When the proportion of the organometallic compound is within the above range, the adhesion between the first resin layer and the polarizer layer can be enhanced.

[1.1.2. UV absorber]
In this embodiment, at least one of the first resin layer and the second resin layer preferably contains an ultraviolet absorber. This is because when the first resin layer and the second resin layer are used as protective layers in the polarizing film, deterioration of the polarizer layer due to ultraviolet rays can be suppressed. When the second resin layer does not contain an ultraviolet absorber, the first resin layer preferably contains an ultraviolet absorber.

Examples of the ultraviolet absorber include triazine-based ultraviolet absorbers, benzophenone-based ultraviolet absorbers, benzotriazole-based ultraviolet absorbers, and acrylonitrile-based ultraviolet absorbers. Examples of preferred UV absorbers include 2-(2H-benzotriazol-2-yl)-4-(1,1,3,3-tetramethylbutyl)phenol, 2-(2H-benzotriazol-2-yl )-4,6-bis(1-methyl-1-phenylethyl)phenol, benzotriazoles such as 2-(2'-hydroxy-3'-t-butyl-5'-merylphenyl)-5-chlorobenzotriazole system ultraviolet absorbers. One type of ultraviolet absorber may be used alone, or two or more types may be used in combination.

The content of the ultraviolet absorber in the first resin layer is preferably 20% by weight or more, more preferably 25% by weight or more, and preferably 40% by weight or less, more preferably 30% by weight or less.

[1.1.3. Physical properties of the first resin layer]
The thickness of the first resin layer in the laminate is usually greater than 0 μm, preferably 2 μm or more, more preferably 4 μm or more, preferably 12 μm or less, more preferably 10 μm or less, and most preferably 7 μm or less. When the thickness of the first resin layer is within the above range, a thin resin layer can be arranged as a protective layer with respect to the polarizer layer.

The first resin layer preferably has small optical anisotropy in both the in-plane direction and the thickness direction, and preferably has optical isotropy.
Therefore, the in-plane retardation of the first resin layer is preferably small. Specifically, the in-plane retardation of the first resin layer at a measurement wavelength of 550 nm is preferably 5 nm or less, more preferably 4 nm or less, even more preferably 3 nm or less, and particularly preferably 2 nm or less.
Moreover, the thickness direction retardation of the first resin layer is preferably zero or close to zero. Specifically, the retardation in the thickness direction of the first resin layer at a measurement wavelength of 550 nm is preferably −5 nm or more, more preferably −4 nm or more, still more preferably −3 nm or more, and particularly preferably −2 nm or more, It is preferably 5 nm or less, more preferably 4 nm or less, even more preferably 3 nm or less, and particularly preferably 2 nm or less.

The photoelastic constant of the first resin layer is preferably within a specific range. Specifically ^{, the} lower the photoelastic constant of the ^first resin layer ^is , the better. ×10 ⁻¹³ cm ² /dyn or less. Ideally, it is 0.0×10 ⁻¹³ cm ² /dyn. When the photoelastic constant of the first resin layer is within the above range, the change in retardation due to expansion or contraction stress can be reduced. The photoelastic constant of the first resin layer can be obtained by calculation from the birefringence generated when stress is applied to the first resin layer. As a specific measuring method, the method described in Examples can be adopted.

The first resin layer is preferably transparent from the viewpoint of functioning as a polarizing plate protective film layer as an optical film. Therefore, it is preferable that the total light transmittance of the first resin layer is high. Specifically, the total light transmittance of the first resin layer is preferably 80% or higher, more preferably 85% or higher, and particularly preferably 90% or higher. Total light transmittance can be measured in the wavelength range of 400 nm to 700 nm using an ultraviolet-visible spectrometer.

The haze of the first resin layer is preferably 5% or less, more preferably 3% or less, particularly preferably 1% or less, and ideally 0%. Haze can be measured using a haze meter in accordance with JIS K7361-1997.

[1.2. Second resin layer]
The second resin layer is a layer containing a first resin having a storage modulus of 10 MPa or more and less than 650 MPa.

[1.2.1. Second resin]
The second resin is a resin having a storage elastic modulus of 10 MPa or more and less than 650 MPa measured as a 1 mm film.

The storage modulus of the second resin is usually 10 MPa or more, preferably 50 MPa or more, more preferably 150 MPa or more, and usually less than 650 MPa, preferably 600 MPa or less, more preferably 550 MPa or less. This is because when the storage modulus of the second resin is within the above range, surface irregularities of the second resin layer caused by the base film can be suppressed when the second resin layer is peeled off from the base film. .
The method for measuring the storage elastic modulus of the second resin may be the same as the method for measuring the storage elastic modulus of the first resin.

The second resin preferably has a water vapor transmission rate at 40° C. and 90% RH measured as a film having a thickness of 100 μm within a predetermined range. Specifically, the water vapor transmission rate of the first resin is preferably 4.0 g/(m ² ·day) or less, more preferably 3.0 g/(m 2 ·day) or less, and particularly preferably 2.0 g/(m ² ·day) or less. It is 0 g/(m ² ·day) or less. The lower limit is ideally 0 g/(m ² ·day) or more, and may be 0.1 g/(m ² ·day) or more. The method for measuring the water vapor transmission rate of the second resin may be the same as the method for measuring the water vapor transmission rate of the first resin.

The polymer contained in the second resin usually has thermoplasticity. Since the polymer has thermoplasticity, the second resin may also have thermoplasticity.

The second resin preferably contains a polymer containing an alicyclic structure.
Examples of polymers containing an alicyclic structure that can be contained in the second resin include norbornene polymers, monocyclic cyclic olefin polymers, cyclic conjugated diene polymers, vinyl alicyclic hydrocarbon polymers, and hydrides thereof and hydrides of vinyl aromatic hydrogen polymers. Among these, hydrides of vinyl aromatic hydrogen polymers are preferred because they have good transparency and moldability and are easy to adjust to a desired storage elastic modulus.

A hydride of a vinyl aromatic hydrocarbon polymer means a hydride of a polymer containing the repeating unit [I] derived from an aromatic vinyl compound. A repeating unit derived from an aromatic vinyl compound means a repeating unit having a structure obtained by polymerizing an aromatic vinyl compound. However, the hydride and its constituent units are not limited by the production method.

Examples of the aromatic vinyl compound corresponding to the repeating unit [I] include styrene; Styrenes having an alkyl group having 1 to 6 carbon atoms as a substituent, such as diisopropylstyrene, 4-t-butylstyrene, 5-t-butyl-2-methylstyrene; 4-chlorostyrene, dichlorostyrene, 4-mono Styrenes having a halogen atom as a substituent such as fluorostyrene; Styrenes having an alkoxy group having 1 to 6 carbon atoms as a substituent such as 4-methoxystyrene; Aryl groups as a substituent such as 4-phenylstyrene styrenes; vinylnaphthalenes such as 1-vinylnaphthalene and 2-vinylnaphthalene; and the like. One of these may be used alone, or two or more of them may be used in combination at any ratio. Among these, aromatic vinyl compounds containing no polar group, such as styrene and styrenes having an alkyl group having 1 to 6 carbon atoms as a substituent, are preferred because they can reduce hygroscopicity, and they are easy to obtain industrially. Therefore, styrene is particularly preferred.

The hydrogenated polymer containing the repeating unit [I] derived from the aromatic vinyl compound is preferably a specific hydrogenated block copolymer [E]. Block copolymer hydride [E] is a hydride of block copolymer [D]. Block copolymer [D] is a polymer block composed of polymer block [A] and polymer block [B] or polymer block [C]. The polymer block [A] is a polymer block whose main component is the repeating unit [I] derived from an aromatic vinyl compound. The polymer block [B] is a polymer block mainly composed of repeating units [I] derived from an aromatic vinyl compound and repeating units [II] derived from a chain conjugated diene compound. Polymer block [C] is a polymer block mainly composed of repeating unit [II] derived from a chain conjugated diene compound. Here, "main component" refers to a component that accounts for 50% by weight or more in the polymer block. A repeating unit derived from a chain conjugated diene compound means a repeating unit having a structure obtained by polymerizing a chain conjugated diene compound.

Examples of chain conjugated diene compounds corresponding to the repeating unit [II] include 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene and 1,3-pentadiene. One of these may be used alone, or two or more of them may be used in combination at any ratio. The chain conjugated diene compound may be linear or branched.

A hydride of a vinyl aromatic hydrocarbon polymer is a substance obtained by hydrogenating an unsaturated bond of a vinyl aromatic hydrocarbon polymer. Here, the unsaturated bonds of the vinyl aromatic hydrocarbon polymer to be hydrogenated include the carbon-carbon unsaturated bonds of the main chain and side chains of the polymer, and the carbon-carbon unsaturated bonds of the aromatic ring, Both are included.

The hydride is, for example, in a solution of a vinyl aromatic hydrocarbon polymer, in the presence of a hydrogenation catalyst containing a transition metal such as nickel or palladium, preferably hydrogenating the unsaturated bonds of the polymer by 90% or more. can be manufactured by

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

The molecular weight distribution (Mw/Mn) of the polymer contained in the second resin is preferably 1.2 or more, more preferably 1.5 or more, particularly preferably 1.8 or more, and preferably 3.5 or less. It is more preferably 3.0 or less, particularly preferably 2.7 or less. Here, Mn represents the 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. Moreover, the amount of low-molecular-weight components is reduced by setting the content to the upper limit or less. As a result, the relaxation of the resin layer during high temperature exposure can be suppressed, and the stability of the second resin layer can be enhanced.

The weight average molecular weight (Mw) and number average molecular weight (Mn) can be measured in the same manner as the weight average molecular weight (Mw) and number average molecular weight (Mn) of the first resin.

When the second resin contains the block copolymer hydride [E], the polyethylene terephthalate film as the peelable base film and the second resin layer are easily peeled off during transfer, and peeling occurs at an unintended timing. It is possible to impart an appropriate degree of releasability to the extent that it is difficult to remove. Therefore, web handleability of the laminate can be improved. In addition, since it is possible to improve the releasability between the base film and the second resin layer, for example, a resin having low adhesion to the base film is selected as the resin contained in the first resin layer. be able to.

The second resin may further contain optional components in combination with the polymer described above. Optional components include, for example, plasticizers and/or softeners; organometallic compounds; stabilizers such as antioxidants and light stabilizers; resin modifiers such as lubricants; coloring agents such as dyes and pigments; agent; and the like. One of these components may be used alone, or two or more of them may be used in combination at any ratio.

In addition, the second resin preferably contains a plasticizer and/or a softening agent (plasticizer or softening agent, or both) as optional components. By containing a plasticizer and/or a softener, the storage modulus of the second resin can be easily adjusted. Moreover, the moldability (for example, extensibility) of the second resin can be improved.

As the plasticizer and/or softener, those that can be uniformly dissolved or dispersed in the second resin can be used. Specific examples of plasticizers and/or softeners include ester plasticizers such as polyhydric alcohol ester plasticizers and polycarboxylic acid ester plasticizers; phosphate ester plasticizers; carbohydrate ester plasticizers; of polymeric softeners. A polyhydric alcohol ester-based plasticizer represents an ester-based plasticizer composed of a polyhydric alcohol and a monovalent carboxylic acid. A polyvalent carboxylic acid ester-based plasticizer represents an ester-based plasticizer composed of a polyvalent carboxylic acid and a monohydric alcohol.

Examples of the polyhydric alcohol, which is a raw material for the ester plasticizer, are not particularly limited, but ethylene glycol, glycerin, and trimethylolpropane are preferable.

Examples of polyhydric alcohol ester plasticizers include ethylene glycol ester plasticizers, glycerin ester plasticizers, and other polyhydric alcohol ester plasticizers.

Examples of polycarboxylic acid ester plasticizers include dicarboxylic acid ester plasticizers and other polycarboxylic acid ester plasticizers.

Examples of phosphate plasticizers include alkyl phosphates such as triacetyl phosphate and tributyl phosphate; cycloalkyl phosphates such as tricyclopentyl phosphate and cyclohexyl phosphate; aryl phosphates such as triphenyl phosphate and tricresyl phosphate. is mentioned.

Preferred examples of carbohydrate ester plasticizers include glucose pentaacetate, glucose pentapropionate, glucose pentabutyrate, saccharose octaacetate, saccharose octabenzoate, etc. Of these, saccharose octaacetate is more preferred.

Examples of polymeric softeners include aliphatic hydrocarbon polymers, alicyclic hydrocarbon polymers, polyethyl acrylate, polymethyl methacrylate, copolymers of methyl methacrylate and 2-hydroxyethyl methacrylate, methacrylic Acrylic polymers such as copolymers of methyl acid, methyl acrylate and 2-hydroxyethyl methacrylate; vinyl polymers such as polyvinyl isobutyl ether and poly N-vinylpyrrolidone; polystyrene, poly 4-hydroxystyrene and the like styrenic polymers; polyesters such as polybutylene succinate, polyethylene terephthalate and polyethylene naphthalate; polyethers such as polyethylene oxide and polypropylene oxide; polyamides, polyurethanes, polyureas and the like.

Specific examples of aliphatic hydrocarbon polymers include low molecular weight substances such as polyisobutylene, polybutene, poly-4-methylpentene, poly-1-octene, ethylene/α-olefin copolymers, and hydrides thereof; polyisoprene, Examples include low-molecular-weight compounds such as polyisoprene-butadiene copolymers and hydrides thereof. The aliphatic hydrocarbon polymer preferably has a number average molecular weight of 300 to 5,000 from the viewpoint of uniform dissolution or dispersibility in the cycloolefin resin.

These polymer softeners may be homopolymers consisting of one type of repeating unit, or copolymers having a plurality of repeating structures. Moreover, one type of the polymer softening agent may be used alone, or two or more types may be used in combination at an arbitrary ratio.

As the plasticizer and/or softener, one or more selected from the group consisting of an ester plasticizer and an aliphatic hydrocarbon polymer are particularly preferable because they have particularly excellent compatibility with the components contained in the first resin.

The total amount of the plasticizer and the softening agent is preferably 5 parts by weight or more, more preferably 10 parts by weight or more, and still more preferably 20 parts by weight or more with respect to 100 parts by weight of the polymer contained in the second resin, It is preferably 100 parts by weight or less, more preferably 70 parts by weight or less, and even more preferably 50 parts by weight or less. This is because the storage elastic modulus of the second resin can be easily adjusted to a desired range when the total ratio of the plasticizer and the softener in the second resin is within the above range. Moreover, it is because the moldability of the second resin can be improved.

The second resin preferably contains an organometallic compound as an optional component. This is because the adhesion between the second resin layer and the adhesive layer can be improved by including the organometallic compound in the second resin. In addition, it is possible to improve adhesion when the second resin layer is placed on, for example, a glass member of a display device without an adhesive layer intervening therebetween.

The type and content of the organometallic compound that can be contained in the second resin can be the same as those described for the type and content of the organometallic compound that can be contained in the first resin.

[1.2.2. UV absorber]
In this embodiment, at least one of the first resin layer and the second resin layer preferably contains an ultraviolet absorber. Therefore, when the first resin layer does not contain an ultraviolet absorber, the second resin layer preferably contains an ultraviolet absorber.

The content of the ultraviolet absorber in the second resin layer is preferably 20% by weight or more, more preferably 25% by weight or more, and preferably 40% by weight or less, more preferably 30% by weight or less. For the type of ultraviolet absorber contained in the second resin layer, see [1.1. First resin layer] [1.1.2. Ultraviolet Absorber].

[1.2.3. Physical properties of the second resin layer]
The thickness of the second resin layer in the laminate is usually greater than 0 μm, preferably 2 μm or more, more preferably 4 μm or more, and preferably 12 μm or less, more preferably 10 μm or less, still more preferably 7 μm or less. When the thickness of the second resin layer is within the above range, a thin resin layer can be arranged as a protective layer with respect to the polarizer layer.

The second resin layer preferably has small optical anisotropy in both the in-plane direction and the thickness direction, and preferably has optical isotropy.
Therefore, the in-plane retardation of the second resin layer is preferably small. Specifically, the in-plane retardation of the second resin layer at a measurement wavelength of 550 nm is preferably 5 nm or less, more preferably 4 nm or less, even more preferably 3 nm or less, and particularly preferably 2 nm or less.
Moreover, the thickness direction retardation of the second resin layer is preferably zero or close to zero. Specifically, the retardation in the thickness direction of the second resin layer at a measurement wavelength of 550 nm is preferably −5 nm or more, more preferably −4 nm or more, still more preferably −3 nm or more, and particularly preferably −2 nm or more, It is preferably 5 nm or less, more preferably 4 nm or less, even more preferably 3 nm or less, and particularly preferably 2 nm or less.

The photoelastic constant of the second resin layer is preferably within a specific range. Specifically, the photoelastic constant of the second resin layer is preferably as small as possible, preferably 10×10 ⁻¹³ cm ² /dyn or less, more preferably 5×10 ⁻¹³ cm ² /dyn or less, particularly preferably 2 ×10 ⁻¹³ cm ² /dyn or less. Ideally, it is 0.0×10 ⁻¹³ cm ² /dyn. When the photoelastic constant of the second resin layer is within the above range, the change in retardation due to expansion or contraction stress can be reduced.

The second resin layer is preferably transparent from the viewpoint of functioning as a polarizing plate protective film layer as an optical film. Therefore, the total light transmittance of the second resin layer is preferably high. Specifically, the total light transmittance of the second resin layer is preferably 80% or higher, more preferably 85% or higher, and particularly preferably 90% or higher.

The haze of the second resin layer is preferably 5% or less, more preferably 3% or less, particularly preferably 1% or less, and ideally 0%.

Methods for measuring the photoelastic constant, total light transmittance and haze of the second resin layer are described in [1.1.3. Physical properties of first resin layer].

[1.3. Laminated portion of first resin layer and second resin layer]
In the laminate according to the present invention, the first resin layer and the second resin layer each contain a resin having a predetermined storage elastic modulus, so that the laminate portion of the first resin layer and the second resin layer serves as a polarizer of the polarizing film. It can be used as a resin layer that can suppress cracking of the layer, and when the resin layer is peeled off from the peelable base film, it can alleviate the occurrence of surface unevenness of the resin layer due to the uneven structure of the base film. In this embodiment, the difference between the storage elastic modulus of the first resin of the first resin layer and the storage elastic modulus of the second resin of the second resin layer is preferably within a predetermined range. Specifically, the difference between the storage modulus of the first resin and the storage modulus of the second resin is preferably 200 MPa or more, more preferably 250 MPa or more, still more preferably 300 MPa or more, and preferably 1000 MPa or less. , preferably 800 MPa or less, more preferably 700 MPa or less. This is because, by setting the storage elastic moduli of the first resin and the second resin within the above range, the above-described effects of suppressing cracks in the polarizer and alleviating surface irregularities of the second resin layer are easily exhibited.

The laminated portion of the first resin layer and the second resin layer in the laminate can function as a protective layer for the polarizer layer in the polarizing film. The total thickness of the first resin layer and the second resin layer is preferably 12 μm or less, more preferably 10 μm or less. Still, the lower limit of the total thickness of the first resin layer and the second resin layer can be, for example, 4 μm.

[1.4. Peelable base film]
The peelable base film is used to support the first resin layer and the second resin layer in the laminate. “Peelable” means that the second resin layer placed on the surface of the base film can be peeled off.

The tensile modulus of the base film is preferably within a predetermined range. Specifically, the tensile modulus of the base film is preferably 2000 MPa or more, more preferably 2500 MPa or more, preferably 5000 MPa or less, and more preferably 4500 MPa or less. When the tensile modulus of elasticity of the base film is equal to or higher than the lower limit, adhesion between the base film and the second resin layer can be improved. While suppressing peeling between the base film and the second resin layer, it is possible to suppress curling at the end of the laminate.
The tensile modulus can be measured based on JIS K7127 using a tensile tester (manufactured by Instron Japan Company Limited, trade name "Electromechanical Universal Material Testing Machine (5564)").

As the base film, a resin film made of a resin such as polyethylene terephthalate, polyethylene, or polypropylene is usually used. If an ultraviolet curable adhesive is used to bond the polarizer layer and the first resin layer together, a resin film with low UV-B absorption is preferred. “UV-B” refers to light with a wavelength of 280 nm or more and 315 nm or less, unless otherwise specified. A release treatment may be applied to the surface of the base film in order to facilitate the peeling of the second resin layer.

Examples of the release treatment include a treatment for forming a layer of a release agent on the surface of the base film. Examples of the release agent include silicone-based release agents such as polydimethylsiloxane, fluorine-based release agents such as alkyl fluoride, and long-chain alkyl-based release agents. Among them, a silicone release agent is preferable because of its good releasability and workability.

[1.5. Application of laminate]
The laminate of the present invention can be used as a transfer laminate for forming a resin layer as a protective layer on a polarizer layer by a transfer method in a method for producing a polarizing film.

[2. Laminate with adhesive layer]
FIG. 2 is a cross-sectional view schematically showing a laminate 200 with an adhesive layer according to one embodiment of the present invention. As shown in FIG. 2, the adhesive layer-attached laminate 200 includes a first resin layer 201, a second resin layer 202, and an adhesive layer 203 in this order in the thickness direction. Moreover, the adhesive layer-attached laminate 200 has a thickness of 2 μm or more and 25 μm or less.

The first resin layer and the second resin layer are described in [1. Laminate].

The adhesive layer is a layer provided on the second resin layer. The adhesive layer 203 is normally provided directly on the second resin layer 202 as shown in FIG.

The adhesive layer can bond the laminated portion of the first resin layer and the second resin layer to another optical member using its adhesive strength. Therefore, for example, when a polarizing film is formed by arranging a polarizer layer on the first resin layer, the polarizing film can be attached to another optical member. Further, for example, when a polarizing film is incorporated into a display device having a display element such as a liquid crystal cell and an organic EL element, the adhesive layer of the polarizing film is adhered to the display element.

Examples of adhesives as materials for the adhesive layer include rubber-based adhesives, acrylic adhesives, polyvinyl ether-based adhesives, urethane-based adhesives, silicone-based adhesives, and polyolefin-based adhesives. Among them, acrylic pressure-sensitive adhesives and polyolefin-based pressure-sensitive adhesives are preferred from the viewpoint of heat resistance and productivity, and acrylic pressure-sensitive adhesives are particularly preferred. Moreover, one type of pressure-sensitive adhesive may be used alone, or two or more types may be used in combination at an arbitrary ratio.

The thickness of the adhesive layer is preferably 2.0 μm or more, more preferably 5.0 μm or more, preferably 25.0 μm or less, more preferably 20.0 μm or less, and particularly preferably 15.0 μm or less. When the thickness of the adhesive layer is equal to or more than the lower limit of the above range, the adhesive strength of the adhesive layer can be increased, and entrainment of air bubbles during lamination can be suppressed. Moreover, when the thickness of the adhesive layer is equal to or less than the upper limit of the above range, the expansion and contraction behavior of the polarizing film can be suppressed, and bezel-free can be achieved.

A laminate with an adhesive layer is usually obtained by peeling a peelable base film from the second resin layer of the laminate described above and forming an adhesive layer on the second resin layer.

[3. Polarizing film]
FIG. 3 is a cross-sectional view schematically showing a polarizing film according to an embodiment of the invention. As shown in FIG. 3, the polarizing film 300 includes a polarizer layer 304, a first resin layer 301 and a second resin layer 302 in this order in the thickness direction. The polarizing film 300 may include an adhesive layer 305 between the polarizer layer 304 and the first resin layer 301, if necessary.

According to the present invention, since the polarizing film has the above-described first resin layer and second resin layer, cracks in the polarizer layer are suppressed, and a polarizing film having good flatness of the second resin layer can be obtained. can.

[3.1. First Resin Layer and Second Resin Layer]
The first resin layer and the second resin layer are described in [1. Laminate].

[3.2. Polarizer layer]
As the polarizer layer, a film that can transmit one of two linearly polarized lights whose vibration directions intersect at right angles and can absorb or reflect the other can be used. Here, the vibration direction of the linearly polarized light represents the vibration direction of the electric field of the linearly polarized light. Such a film usually has a polarization transmission axis, can transmit linearly polarized light having a vibration direction parallel to the polarization transmission axis, and can absorb or reflect linearly polarized light having a vibration direction perpendicular to the polarization transmission axis.

To give specific examples of the polarizer layer, a film of polyvinyl alcohol resin containing a vinyl alcohol polymer such as polyvinyl alcohol or partially formalized polyvinyl alcohol is dyed with a dichroic substance such as iodine or a dichroic dye. , stretching treatment, cross-linking treatment and the like in an appropriate order and method. The polarizer layer preferably contains a polyvinyl alcohol resin.

The thickness of the polarizer layer is preferably greater than 1 μm, more preferably 2 μm or more, particularly preferably 3 μm or more, and preferably 12 μm or less, more preferably 10 μm or less, and particularly preferably 7 μm or less. When the thickness of the polarizer layer is larger than the lower limit of the range, the optical performance of the polarizing film can be sufficiently enhanced. Moreover, when the thickness of the polarizer layer is equal to or less than the upper limit of the range, the flexibility of the polarizing film can be effectively increased.

[3.3. any layer]
The polarizing film should have at least the polarizer layer, the first resin layer and the second resin layer, and may combine any layers as necessary.

[3.3.1. Adhesive layer]
The polarizing film may include an adhesive layer as an optional layer between the first resin layer and the polarizer layer. By using the adhesive layer, the first resin layer and the polarizer layer can be strongly bonded.

The adhesive layer is made of an adhesive that bonds the first resin layer and the polarizer layer. Examples of adhesives include acrylic adhesives, epoxy adhesives, urethane adhesives, polyester adhesives, polyvinyl alcohol adhesives, polyolefin adhesives, modified polyolefin adhesives, and polyvinyl alkyl ether adhesives. , rubber-based adhesives, vinyl chloride-vinyl acetate-based adhesives, SEBS (styrene-ethylene-butylene-styrene copolymer)-based adhesives, ethylene-based adhesives such as ethylene-styrene copolymers, ethylene-(meth) Acrylic acid ester-based adhesives such as methyl acrylate copolymers and ethylene-(meth)ethyl acrylate copolymers can be used. As the adhesive, an ultraviolet curable adhesive is preferable because the adhesive can be cured in a short time.

The thickness of the adhesive layer is usually greater than 0 μm, preferably 0.1 μm or more, more preferably 1 μm or more, and preferably 5 μm or less, more preferably 3 μm or less. When the thickness of the adhesive layer is within the above range, a good appearance can be obtained, and the first resin layer and the polarizer layer can be strongly bonded.

[3.3.2. Optically anisotropic layer]
The polarizing film may have an optically anisotropic layer as an arbitrary layer. For example, a polarizing film for application to a liquid crystal display device includes an optical compensation film layer for compensating for the viewing angle dependence of the liquid crystal contained in the liquid crystal cell and for compensating for the axial misalignment of the polarizer layer. It may be provided as a layer. Further, for example, a polarizing film for application to a liquid crystal display device may have a λ/4 layer as an optically anisotropic layer in combination with an optical compensation film layer in order to realize a reflection suppressing function. An organic EL display device does not normally require a polarizing film for RGB light emission and image display. It is possible to improve the quality of

A λ/4 layer means a layer having an in-plane retardation within a predetermined range at a wavelength of 550 nm. Specifically, the in-plane retardation of the λ/4 layer at a wavelength of 550 nm is preferably 110 nm or more, more preferably 120 nm or more, particularly preferably 125 nm or more, preferably 165 nm or less, more preferably 155 nm or less, especially It is preferably 150 nm or less.

From the viewpoint of viewing angle characteristics, the three-dimensional refractive index of the λ/4 layer preferably exhibits uniaxiality, where nx>ny=nz. Further, the three-dimensional refractive index of the λ/4 layer preferably satisfies nx>nz>ny, and ideally satisfies the relationship (nx−nz)/(nx−ny)=0.5.

The slow axis of the λ/4 layer is preferably 45° ± 5° (ie 40° to 50°), more preferably 45° ± 3° (ie 42° to 48°), particularly preferably 45°±1° (ie 44° to 46°). Thereby, a circularly polarizing plate can be obtained as a combination of the polarizer layer and the λ/4 layer.

The λ/4 layer preferably has reverse wavelength dispersion characteristics. The reverse chromatic dispersion characteristic means a characteristic in which in-plane retardation Re(450) and Re(550) at measurement wavelengths of 450 nm and 550 nm satisfy Re(450)<Re(550). A λ/4 layer having reverse wavelength dispersion characteristics can exhibit its optical function in a wide wavelength range.

A λ/4 layer may be produced, for example, as a stretched film obtained by stretching a pre-stretched film made of a suitable resin. Further, the λ / 4 layer is, for example, a liquid crystal cured layer obtained by forming a layer of a liquid crystal composition containing an appropriate liquid crystal compound, orienting the molecules of the liquid crystal compound, and then curing the liquid crystal composition. may be manufactured. Above all, from the viewpoint of obtaining a thin and flexible polarizing film, the λ/4 layer is preferably a liquid crystal cured layer. A λ/4 layer as such a liquid crystal cured layer can be manufactured, for example, by the method described in International Publication No. 2016/121602.

The polarizing film may further include a λ/2 layer as an optional layer. A λ/2 layer means a layer having an in-plane retardation within a predetermined range at a wavelength of 550 nm. Specifically, the in-plane retardation of the λ/2 layer at a wavelength of 550 nm is preferably 240 nm or more, more preferably 250 nm or more, preferably 300 nm or less, more preferably 280 nm or less, and particularly preferably 265 nm or less. .

From the viewpoint of viewing angle characteristics, the three-dimensional refractive index of the λ/2 layer preferably exhibits uniaxiality where nx>ny=nz. Furthermore, the three-dimensional refractive index of the λ/2 layer preferably satisfies nx>nz>ny, and ideally satisfies the relationship (nx−nz)/(nx−ny)=0.5.

The slow axis of the λ/2 layer may be arbitrarily set according to the optical function desired to be exhibited by the polarizing film. For example, when the polarizing film comprises a combination of a λ / 2 layer and a λ / 4 layer, the angle θ (λ / 4) formed by the slow axis of the λ / 4 layer with respect to a certain reference direction, and When the angle θ (λ/2) formed by the λ/2 layer satisfies the formula (X): “θ (λ/4) = 2θ (λ/2) + 45°”, the λ / 2 layer and λ The combination of the λ/4 layers is a broadband λ/4 layer that can give in-plane retardation of approximately 1/4 the wavelength of the light to the light passing through the λ/2 and λ/4 layers in a wide wavelength range. It can function as four plates (see JP-A-2007-004120). Therefore, when trying to obtain a polarizing film that can function as a circularly polarizing plate in a wide wavelength range, the slow axes of the λ / 2 layer and the λ / 4 layer are set so as to satisfy a relationship close to the above formula (X). preferably. For example, the slow axes of the λ/2 layer and the λ/4 layer preferably satisfy any one of the following relationships (X1) to (X3).

(X1) The angle formed by the slow axis of one of the λ/4 layer and the λ/2 layer with respect to the polarization transmission axis of the polarizer layer is preferably 75° ± 5° (that is, 70° to 80°), and more preferably 75°±3° (ie 72° to 78°), particularly preferably 75°±1° (ie 74° to 76°) and the retardation of the other of the λ/4 and λ/2 layers the angle formed by the phase axis with respect to the polarization transmission axis of the polarizer layer is preferably 15°±5° (ie 10° to 20°), more preferably 15°±3° (ie 12° to 18°); Especially preferred is 15°±1° (ie 14° to 16°).

(X2) The angle formed by the slow axis of one of the λ/4 layer and the λ/2 layer with respect to the polarization transmission axis of the polarizer layer is preferably 15° ± 5° (that is, 10° to 20°), and more preferably 15°±3° (ie 12° to 18°), particularly preferably 15°±1° (ie 14° to 16°) and the retardation of the other of the λ/4 and λ/2 layers the angle formed by the phase axis with respect to the polarization transmission axis of the polarizer layer is preferably 75°±5° (ie 70° to 80°), more preferably 75°±3° (ie 72° to 78°); Especially preferred is 75°±1° (ie 74° to 76°).

(X3) The angle formed by the slow axis of one of the λ/4 layer and the λ/2 layer with respect to the polarization transmission axis of the polarizer layer is preferably 22.5° ± 5° (that is, 17.5° to 27° .5°), more preferably 22.5° ± 3° (ie 19.5° to 25.5°), particularly preferably 22.5° ± 1° (ie 21.5° to 23.5°) and the angle formed by the slow axis of the other of the λ/4 layer and the λ/2 layer with respect to the polarization transmission axis of the polarizer layer is preferably 90° ± 5° (that is, 85° to 95°) , more preferably 90°±3° (ie 87° to 93°), particularly preferably 90°±1° (ie 89° to 91°).

Here, the direction in which the slow axis of one of the λ/4 layer and the λ/2 layer forms the angle with respect to the polarization transmission axis of the polarizer layer is usually the other of the λ/4 layer and the λ/2 layer. is the same as the direction in which the slow axis of is at an angle with respect to the polarization transmission axis of the polarizer layer.

The λ/2 layer preferably has reverse wavelength dispersion characteristics. A λ/2 layer having reverse wavelength dispersion characteristics can exhibit its optical function in a wide wavelength range.

A λ/2 layer may for example be produced as a stretched film. The λ/2 layer may also be manufactured as a liquid crystal cured layer, for example. Among them, the λ/2 layer is preferably a liquid crystal cured layer from the viewpoint of obtaining a thin and flexible polarizing film. A λ/2 layer as such a liquid crystal cured layer can be manufactured, for example, by the method described in International Publication No. 2016/121602.

The polarizing film may further comprise a positive C-plate layer as an optional layer. In particular, if the polarizing film does not comprise a λ/4 layer or a λ/2 layer with a three-dimensional refractive index that satisfies the relationship (nx−nz)/(nx−ny)=0.5, the polarizing film is positive. A C-plate layer is preferably provided. A positive C-plate layer is a layer that functions as a positive C-plate. Even if the polarizing film does not have a λ/4 layer or a λ/2 layer with a three-dimensional refractive index that satisfies the relationship (nx−nz)/(nx−ny)=0.5, there is a positive C-plate layer. Therefore, it is possible to appropriately adjust the refractive index in the thickness direction and improve the viewing angle characteristics. Also, a plurality of positive C plate layers may be used in combination with the optically anisotropic layers such as the λ/2 layer and the λ/4 layer described above.

A positive C-plate layer may be manufactured, for example, as a stretched film. The positive C-plate layer may also be manufactured as, for example, a liquid crystal cured layer. Above all, from the viewpoint of obtaining a thin and flexible polarizing film, the positive C plate layer is preferably a liquid crystal cured layer. Such a positive C plate layer as a liquid crystal cured layer can be produced by the methods described in, for example, Japanese Patent Application Laid-Open Nos. 2015-14712 and 2015-57646. Further, as the liquid crystalline compound for manufacturing the positive C plate layer, one having reverse wavelength dispersion characteristics may be used.

The arbitrary layer mentioned above may use only 1 type and may use it in combination of 2 or more types. Also, the number of layers may be one or two or more. Furthermore, the positions of the layers described above are arbitrary as long as they do not significantly impair the effects of the present invention.

[3.3.3. Any other layer]
Further examples of optional layers that the polarizing film may have include a clear hard coat layer, an antiglare hard coat layer, an antireflection layer, an antistatic layer, an antifouling layer, and the like. The arbitrary layer mentioned above may use only 1 type and may use it in combination of 2 or more types. Moreover, the number of arbitrary layers may be one layer, or two or more layers. Furthermore, the position of any layer is not limited as long as it does not significantly impair the effects of the present invention.

[3.4. Thickness and use of polarizing film]
According to the present invention, the polarizer layer can be effectively protected even if the protective layer composed of the laminated portion of the first resin layer and the second resin layer is thin. It is possible. The thickness of the polarizing film is preferably 40 µm or more, more preferably 50 µm or more, particularly preferably 60 µm or more, and preferably 110 µm or less, more preferably 90 µm or less, and particularly preferably 70 µm or less.

A polarizing film can usually be used in combination with a display member of a display device. Examples of the display include a liquid crystal panel as a display for liquid crystal display devices and an organic electroluminescence panel as a display for organic electroluminescence display devices. A polarizing film is usually provided on the viewing side of these displays.

[4. Polarizing film with adhesive layer]
FIG. 4 is a cross-sectional view schematically showing a polarizing film with an adhesive layer according to one embodiment of the present invention. As shown in FIG. 4, the adhesive layer-attached polarizing film 400 includes a polarizer layer 404, a first resin layer 401, a second resin layer 402, and an adhesive layer 403 in this order in the thickness direction. The polarizing film 400 with an adhesive layer has an adhesive layer 405 between the polarizer layer 404 and the first resin layer 401 as necessary. The laminated film 400 with adhesive layer shown in FIG. It can be regarded as a configuration having a provided polarizer layer.

The adhesive layer-attached laminate and the polarizer layer are described in [2. Laminate with adhesive layer] and [3. Polarizing film] [3.2. polarizer layer].

[5. Method for manufacturing polarizing film]
The method for producing the polarizing film according to the present invention is not limited as long as the polarizing film described above can be obtained. For example, a step (A) of forming a second resin layer by applying a second resin liquid containing a second resin on a peelable base film and drying it, and applying the first resin on the second resin layer. The step (B) of applying and drying the first resin liquid containing the first resin layer to form the first resin layer, the step (C) of bonding the polarizer layer and the first resin layer, and the step (C) of bonding the second resin layer to the substrate A polarizing film may be produced by a method for producing a polarizing film including, in this order, the step (D) of peeling off the film.

[5.1. Step (A): Formation of second resin layer]
In step (A), a second resin liquid containing a second resin is applied onto a peelable base film and dried to form a second resin layer. The second resin liquid is a liquid material for forming the second resin layer. Therefore, the second resin liquid usually contains each component that can be contained in the second resin. Specifically, the second resin liquid contains a polymer, and may optionally contain optional components contained in the second resin, an ultraviolet absorber, and a solvent. Some or all of the polymer, optional components, and non-volatile components such as UV absorbers may be dissolved in the solvent. Also, part or all of the non-volatile components may be dispersed in a solvent.

As the solvent, an organic solvent is preferable, and an organic solvent capable of dissolving the polymer contained in the second resin is particularly preferable. Examples of the solvent include hydrocarbon solvents such as cyclohexane and toluene; cyclic ether solvents such as tetrahydrofuran; and the like. One type of solvent may be used alone, or two or more types may be used in combination at an arbitrary ratio.

The concentration of the non-volatile component in the second resin liquid can be arbitrarily set within a range in which the second resin liquid has a viscosity suitable for coating. A specific concentration range is preferably 5% by weight or more, more preferably 10% by weight or more, particularly preferably 13% by weight or more, preferably 35% by weight or less, more preferably 30% by weight or less, and particularly preferably 25% by weight or less.

Although the shape of the peelable base film is not limited, it is preferably a long film.

Examples of methods for applying the second resin liquid to the base film include curtain coating, extrusion coating, roll coating, spin coating, dip coating, bar coating, spray coating, slide coating, and printing. A coating method, a gravure coating method, a die coating method, a gap coating method, a dipping method, and the like are included.

A layer of the second resin liquid is formed on the peelable substrate film by applying the second resin liquid to the peelable substrate film. By drying the second resin liquid after coating, volatile components such as the solvent are removed from the layer of the second resin liquid, so that a second resin layer containing the second resin can be obtained.

The specific drying temperature may vary depending on the types and amounts of the polymer, antiplasticizer and solvent, but in general it is preferably 90°C or higher, more preferably 100°C or higher, and particularly preferably 110°C or higher. , preferably 140° C. or lower, more preferably 135° C. or lower, particularly preferably 130° C. or lower.

A specific drying time may vary depending on the types and amounts of the polymer, antiplasticizer and solvent, but in general it is preferably 30 seconds or longer, more preferably 60 seconds or longer, and particularly preferably 90 seconds or longer. , preferably 5 minutes or less, more preferably 4 minutes or less, and particularly preferably 3 minutes or less.

[5.2. Step (B): Formation of first resin layer]
In step (B), a first resin liquid containing the first resin is applied onto the second resin layer and dried to form a first resin layer. The first resin liquid is a liquid material for forming the first resin layer. Therefore, the first resin liquid usually contains each component that can be contained in the first resin. Specifically, the first resin liquid may contain a polymer, a solvent, optional components contained in the second resin, and an ultraviolet absorber, if necessary. Some or all of the polymer, optional components, and non-volatile components such as UV absorbers may be dissolved in the solvent. Also, part or all of the non-volatile components may be dispersed in a solvent.

The solvent used in the first resin liquid, its content, and the coating method and drying method of the first resin liquid are described in [5.1. Step (A): Formation of Second Resin Layer].

[5.3. Step (C): Bonding of first resin layer and polarizer layer]
In step (C), the polarizer layer and the first resin layer are bonded together. The bonding between the first resin layer and the polarizer layer may be performed via an adhesive, if necessary. When the first resin layer and the second resin layer are formed in the form of a long base film, the long first resin layer and the long polarizer layer are usually bonded via an adhesive as necessary. , using a bonding tool such as a pinch roller.

[5.4. Step (D): Peeling of base film]
In step (D), the base film is peeled off. Usually, peeling of the base film is performed continuously. At this time, it is preferable to appropriately set the peeling speed within a range in which breakage of the first resin layer and the second resin layer can be suppressed. The specific peeling speed of the base film is preferably 10 m/min or more, more preferably 15 m/min or more, particularly preferably 20 m/min or more, preferably 70 m/min or less, more preferably 60 m/min or less. , particularly preferably 50 m/min or less.

[5.5. Other processes]
The manufacturing method of the polarizing film mentioned above may also contain arbitrary processes as needed. Examples of optional steps include the step of disposing the optically anisotropic layer and the step of forming the adhesive layer.

EXAMPLES 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 without departing from the scope of the claims of the present invention and their equivalents.

In the following description, "%" and "parts" representing amounts are by weight unless otherwise specified. In addition, unless otherwise specified, the operations described below were performed in normal temperature and normal pressure atmosphere.

In the following description, the abbreviation “St” may be used to refer to a repeating unit derived from styrene, and the “St block” may refer to a polymer block formed from repeating units derived from styrene.
In the following description, an isoprene-derived repeating unit may be represented by the abbreviation "IP", and a polymer block formed of isoprene-derived repeating units may be represented by an "IP block".
In the following description, a random polymer block formed of repeating units derived from styrene and repeating units derived from isoprene may be referred to as "St-IP block".

[Evaluation method]
[Measurement method of weight average molecular weight Mw and number average molecular weight Mn of polymer]
The weight-average molecular weight Mw and number-average molecular weight Mn of the polymer were measured using a gel permeation chromatography (GPC) system ("HLC8020GPC" manufactured by Tosoh Corporation) in terms of polystyrene or polyisoprene. Tetrahydrofuran was used as the solvent when polystyrene was used as the standard. Moreover, when polyisoprene was used as a standard substance, cyclohexane was used as a solvent. The temperature at the time of measurement was 38°C.

[Method for measuring hydrogenation rate of polymer]
The hydrogenation rate of the polymer was measured by ¹ H-NMR measurement.

[Method for measuring thickness]
Film thickness was measured with a snap gauge.

[Method for measuring storage modulus]
A measurement film having a thickness of 1 mm was prepared by heat-melting and molding the resin to be measured using a hot-melt press under the conditions of a clearance of 1 mm, a temperature of 250° C., and a pressure of 30 MPa, and the storage elastic modulus was measured. . The storage modulus is measured using a dynamic viscoelasticity measuring device ("ARES" manufactured by TA Instruments Japan Co., Ltd.) under conditions: a temperature range of -100°C to +250°C and a heating rate of 5°C/min. bottom. The storage modulus at 23°C was read from the measured results.

[Method for measuring water vapor transmission rate]
A measurement film having a thickness of 100 μm was prepared by heat-melting and molding the resin to be measured using a hot-melt press under the conditions of a clearance of 100 μm, a temperature of 250° C., and a pressure of 30 MPa, and the water vapor transmission rate was measured. . The water vapor transmission rate was measured using a water vapor transmission rate measuring device ("PERMATRAN-W" manufactured by MOCON) according to JIS K 7129 B method under conditions of a temperature of 40°C and a humidity of 90% RH.

[Method for measuring photoelastic constant]
A first resin liquid and a second resin liquid (resin liquid) in Examples and Comparative Examples, and a PET film (polyethylene terephthalate film; "MRV38" manufactured by Mitsubishi Chemical Co., Ltd.) having a release treatment with silicone on the surface were prepared. A die coater was used to apply the above resin solution onto the PET film. After that, the solvent component was volatilized by drying at 100° C. for 2 minutes to obtain a resin layer with a thickness of 10 μm. The resin layer was peeled off from the PET film and used as a resin layer for measurement. A resin layer for measurement using each first resin liquid and a resin layer for measurement using each second resin liquid in Examples and Comparative Examples were prepared, and the photoelastic constant was measured.

A film-shaped resin layer for measurement was cut out to prepare a plurality of film pieces each having a width of 1 cm. Weights of 50 g, 100 g, 150 g and 200 g were suspended from these film pieces, and in-plane retardation was measured at a measurement wavelength of 550 nm. The in-plane retardation was measured using a phase difference meter ("Axo Scan" manufactured by AXOMETRICS). The birefringence was obtained by dividing the measured in-plane retardation by the thickness of the resin layer. The obtained birefringence and the magnitude of the force per unit cross-sectional area applied to the resin layer by the weight corresponding to the birefringence are plotted in a coordinate system with the magnitude of the force on the horizontal axis and the birefringence on the vertical axis. plotted. An approximate straight line was obtained from the obtained plots by the method of least squares. As the slope of this approximate straight line, the photoelastic constant of the resin layer for measurement was obtained.

[Method for measuring retardation]
Using the same method as the method for forming the resin layer for measurement in the method for measuring the photoelastic constant, a resin layer having a thickness corresponding to the first resin layer and a resin layer having a thickness corresponding to the second resin layer (2 μm to 5 μm ) was obtained as a resin layer for measurement. The in-plane retardation Re and thickness direction retardation Rth at a measurement wavelength of 550 nm were measured for the obtained resin layer for measurement using a retardation meter ("Axo Scan" manufactured by AXOMETRICS).

[Method for measuring transmittance at 380 nm]
A resin layer for measurement was prepared in the same manner as in the retardation measurement method. A glass substrate ("Eagle XG" manufactured by Corning; thickness 0.5 mm) was prepared. A sample having a layer structure of glass substrate/optical adhesive sheet/resin layer for measurement was obtained by bonding a measurement resin layer to the glass substrate via an optical adhesive sheet ("LUCIACS CS9861US" manufactured by Nitto Denko). rice field. Since the glass substrate and the optical pressure-sensitive adhesive sheet have no absorption at a wavelength of 380 nm, the light transmittance of the sample matches the light transmittance of the resin layer for measurement. Therefore, a spectrophotometer ("V-7200" manufactured by JASCO Corporation) was used to measure the light transmittance at a wavelength of 380 nm.

[Method for evaluating relaxation of surface unevenness of second resin layer in laminate]
The base film was peeled off from the laminate having a layer configuration of first resin layer/second resin layer/base film to expose the second resin layer. Peel off the light release liner of the optical adhesive sheet ("LUCIACS CS9861US" manufactured by Nitto Denko), prepare a laminated sample while passing through pinch rolls, peel off the heavy release liner, and inspect the appearance after laminating on glass. bottom. It was evaluated by the following evaluation indices.
S: No defects caused by the uneven structure of the base film were observed. Very good for use.
A: No defects of 15 μm square or more, which are caused by the uneven structure of the base film, were observed. Very good for use.
B: Usable, but defects of more than 15 μm square and less than 20 μm square due to the uneven structure of the base film were confirmed.

[Transferability to polarizing film]
An adhesive is applied to the first resin layer of the laminate having a layer structure of first resin layer/second resin layer/base film, and after lamination with the polarizer layer and drying, the second resin layer of the laminate is dried. Then, the base film was continuously peeled off to expose the second resin layer.
A: The base film could be continuously peeled off from the second resin layer.
B: The peeling force was too strong and peeling from the second resin layer was difficult, or the peeling force was too low and peeling occurred at an unintended timing.

[Web handleability of laminate]
The web handleability of the laminate was evaluated for the following points. In the step of applying the second resin layer to the base film when producing a laminate having a layer structure of first resin layer / second resin layer / base film, there is a gap between the second resin layer and the base film. The presence or absence of peeling and the presence or absence of curling at the edges of the obtained laminate were evaluated. In addition, the laminate was wound into a roll, and the presence or absence of blocking when unwound from the roll was evaluated. When blocking occurs, it usually becomes difficult to stably produce laminates and polarizing films. In addition, when peeling is observed between the second resin layer and the base film, regardless of the presence or absence of curling and blocking at the edges, it is usually difficult to stably produce a laminate having the above-described layer structure. Become.
S: Peeling between the second resin layer and the base film, edge curling, and blocking did not occur.
A: Neither peeling nor blocking occurred between the second resin layer and the base film. Slight curling at the edge was confirmed.
B: No peeling occurred between the second resin layer and the base film. Curl at the edge was confirmed. In addition, blocking was occasionally observed between the second resin layer and the back surface of the base film.
C: Peeling was observed between the second resin layer and the base film.

[Evaluation method for humidification reliability of polarizing film]
A 5 cm square evaluation sample was obtained by bonding the polarizing film to a glass plate. A humidification test was performed by leaving this evaluation sample in an environment with a temperature of 60° C. and a humidity of 95% RH for 500 hours. After the test, the evaluation sample was evaluated for iodine loss at the edge of the polarizing film.
Judgment Criteria A: No iodine omission occurred at the edge.
B: The portion where iodine was missing at the edge was less than 0.1 mm. C: The portion where iodine was missing at the edge was 0.1 mm or more.

[Evaluation method for cracks in polarizer layer of polarizing film]
A 5 cm square evaluation sample was obtained by bonding the polarizing film to a glass plate.
A thermal cycle test of −40° C. for 30 minutes and 85° C. for 30 minutes was performed for 20 cycles, and the length of cracks in the polarizer layer was measured by microscopic observation. When multiple cracks were generated, the average length was evaluated.
A: Less than 0.1 mm B: 0.1 mm or more and less than 0.15 mm C: 0.2 mm or more

[Production Example 1: Preparation of resin X1]
Resin pellets of a norbornene-based polymer (“ZEONOR” manufactured by Nippon Zeon Co., Ltd., glass transition point Tg: 133° C.) were prepared as the resin X1 used as the first resin.

[Production Example 2: Preparation of resin X2]
Resin pellets of a norbornene-based polymer (“ZEONOR” manufactured by Nippon Zeon Co., Ltd., glass transition point Tg: 163° C.) were prepared as the resin X2 used as the first resin.

[Production Example 3: Preparation of resin Y1]
(1. Synthesis of block copolymer)
Resin Y1 used as the second resin was produced by the following procedure.
A stainless steel reactor equipped with a stirrer was thoroughly dried and then purged with nitrogen.
This reactor was charged with 320 parts of dehydrated cyclohexane, 25.0 parts of styrene monomer and 0.38 parts of dibutyl ether to obtain a reaction solution. While stirring this reaction solution at 60° C., 0.36 parts of n-butyllithium solution (15% hexane solution) was added to initiate the first stage polymerization reaction.
After conducting the polymerization reaction for 1 hour, 50.0 parts of a mixed monomer consisting of 25.0 parts of styrene monomer and 25.0 parts of isoprene monomer was added to the reaction solution, and the second-stage polymerization reaction was further continued for 1 hour. gone.
After that, 25.0 parts of styrene monomer was added to the reaction solution, and the third-stage polymerization reaction was carried out for 1 hour.
After that, 0.2 part of isopropyl alcohol was added to the reaction solution to stop the reaction. As a result, a block copolymer having a structure of styrene block/styrene-isoprene random copolymer block/styrene block was obtained in the reaction solution.

(2. Hydrogenation of block copolymer)
The reaction solution was then transferred to a pressure-resistant reactor equipped with a stirrer. Into this pressure-resistant reactor, 10 parts of a silica-alumina-supported nickel catalyst ("E22U" manufactured by Nikki Kagaku Kogyo Co., Ltd., nickel supported amount 60%) was added as a hydrogenation catalyst and mixed. Also, the inside of the reactor was replaced with hydrogen gas. Thereafter, hydrogen was supplied to the reactor while stirring the reaction solution, and a hydrogenation reaction was carried out at a temperature of 160° C. and a pressure of 4.5 MPa for 8 hours.
After completion of the hydrogenation reaction, the reaction solution was filtered to remove the hydrogenation catalyst. Then, the reaction solution was diluted by adding 800 parts of cyclohexane. The diluted reaction solution was poured into 3500 parts of isopropanol to precipitate a hydride of the block copolymer. The isopropanol used was filtered through a filter having a pore size of 1 μm in a class 1000 clean room.
The precipitated block copolymer hydride was separated and recovered by filtration, and dried under reduced pressure at 80° C. for 48 hours.

The block copolymer hydride thus obtained was a ternary block copolymer hydride composed of the St block, the St-IP block and the St block, and the molar ratio of each block was St block/St- IP block/St block=25/50 (St:IP=25:25)/25. This hydride had a weight average molecular weight Mw of 85,000, a molecular weight distribution Mw/Mn of 1.44, and a hydrogenation rate of the main chain and aromatic ring of almost 100%.

(3. Preparation of Resin Y1)
Pentaerythrityl tetrakis [3-(3,5-di-t-butyl-4-hydroxyphenyl) propionate] (manufactured by Matsubara Sangyo Co., Ltd., "Songnox 1010") is added to 100 parts of the block copolymer hydride as an antioxidant. ”) was melted and kneaded to obtain Resin Y1. This resin Y1 was molded into pellets and collected.

[Production Example 4: Preparation of resin Y2]
Resin Y2 used as the second resin was produced by the following procedure.
100 parts of resin Y1 produced in Production Example 1 and 30 parts of polyisobutene (“Nisseki Polybutene HV-300” manufactured by JX Nippon Oil & Energy Corporation, number average molecular weight of 1,400) as a softening agent are melt-kneaded, Resin Y2 was obtained.

[Production Example 5: Production and Evaluation of Resin Y3]
A resin Y3 used as the second resin was produced by the following procedure.
In the second stage polymerization reaction in the production of resin Y1, resin Y3 was synthesized.

The block copolymer hydride contained in the resin Y3 is a ternary block copolymer hydride composed of a St block, an IP block, and a St block, and the molar ratio of each block is St block/IP block. /St block = 25/50/25. This hydride had a weight average molecular weight Mw of 68,000, a molecular weight distribution Mw/Mn of 1.21, and a hydrogenation rate of the main chain and aromatic ring of approximately 100%.

[Example 1]
(1. Preparation of laminate)
Resin X1 was dissolved in a mixed solvent of cyclohexane and ethylcyclohexane at a solid content of 15%, and an ultraviolet absorber (2-(2H-benzotriazol-2-yl)-4-(1,1,3,3-tetramethylbutyl) was added. ) Phenol: After adding “Tinuvin (registered trademark) 329” manufactured by BASF, the first resin liquid was prepared by stirring again and completely dissolving.
Resin Y1 was dissolved in a mixed solvent of cyclohexane and ethylcyclohexane at a solid content of 15%, and an ultraviolet absorber (2-(2H-benzotriazol-2-yl)-4-(1,1,3,3-tetramethylbutyl) was added. ) Phenol: After adding "Tinuvin (registered trademark) 329" manufactured by BASF, the second resin liquid was prepared by stirring again and completely dissolving.
A PET film (polyethylene terephthalate film; "MRV38" manufactured by Mitsubishi Chemical, tensile elastic modulus 4000 MPa) having a surface subjected to release treatment with silicone was prepared. A second resin liquid was applied onto this PET film using a die coater. Then, after drying at 100° C. for 2 minutes, the first resin liquid is further applied and dried at 100° C. for 2 minutes to volatilize the solvent component. A laminate of the first resin layers was formed.

(2. Production of polarizer layer)
An unstretched polyvinyl alcohol film (vinylon film, average degree of polymerization: about 2400, degree of saponification: 99.9 mol %) having a thickness of 20 μm was prepared as a long original film. While continuously conveying this film in the longitudinal direction through guide rolls, the film is subjected to swelling treatment by immersing it in pure water at 30 ° C. for 1 minute, dyeing solution (iodine and potassium iodide at a molar ratio of 1:23 A dyeing treatment was performed by immersing the film in a dye solution containing the dye at a dye concentration of 1.2 mmol/L at 32° C. for 2 minutes to adsorb iodine onto the film. The film was then washed with a 3% boric acid aqueous solution at 35° C. for 30 seconds. After that, the film was stretched 6.0 times at 57° C. in an aqueous solution containing 3% boric acid and 5% potassium iodide. The film was then subjected to a complementary color treatment at 35° C. in an aqueous solution containing 5% potassium iodide and 1.0% boric acid. After that, the film was dried at 60° C. for 2 minutes to obtain a polarizer layer with a thickness of 7 μm. When the degree of polarization of this polarizer layer was measured with an ultraviolet-visible spectrophotometer ("V-7200" manufactured by JASCO Corporation), it was 99.996%.

(3. Preparation of polarizing film)
A TAC film (“KC4UY” thickness 40 μm, saponified product manufactured by Konica Minolta) was prepared and in-line coated with a water-based adhesive (Gohsenex Z-200 3 wt % aqueous solution manufactured by Mitsubishi Chemical). After subjecting the first resin layer of the laminate to in-line corona treatment, it was in-line coated with a water-based adhesive (3 wt % aqueous solution of Gohsenex Z-200 manufactured by Mitsubishi Chemical). Between the water-based adhesive applied surface of the TAC film and the water-based adhesive applied surface of the first resin layer of the laminate, the polarizer layer was laminated and passed through the nip rolls immediately after lamination. Drying was performed to obtain a polarizing film with a base film in which the TAC film, the polarizer layer, the first resin layer, the second resin layer and the base film were laminated in this order.

(4. Formation of adhesive layer)
After peeling off the base film from the polarizing film with the base film, and subjecting the second resin layer to in-line corona treatment, peel off the light release liner of the optical adhesive sheet ("LUCIACS CS9861US" manufactured by Nitto Denko: thickness 25 μm). One side of the optical pressure-sensitive adhesive sheet was exposed by using the pressure-sensitive adhesive sheet, and the laminated body was passed through nip rolls and bonded together. The obtained laminate was evaluated as described above.

[Example 2]
In (1. Production of laminate) in Example 1, no ultraviolet absorber was added to the first resin liquid, and resin Y2 was used as the resin contained in the second resin liquid, and an ultraviolet absorber was added. A laminate, a polarizing film, and a polarizing film with an adhesive layer were prepared in the same manner as in Example 1, except that the thickness of the first resin layer was 2 μm, and the resulting laminate and polarizing film were obtained. The films were evaluated as described above.

[Examples 3 to 6]
In (1. Preparation of laminate) in Example 1, the type of resin in the first resin liquid and the presence or absence of an ultraviolet absorber, the type of resin in the second resin liquid and the presence or absence of an ultraviolet absorber, and the first resin layer and A laminate, a polarizing film, and a polarizing film with an adhesive layer were produced in the same manner as in Example 1, except that each thickness of the second resin layer was as shown in Table 1, and the resulting laminate and polarizing film were obtained. was evaluated as described above.

[Example 7]
Lamination in the same manner as in Example 3 except that an untreated OPP film (biaxially oriented polyolefin film; manufactured by Toray Industries, "New type Torefan BO 40-2500", tensile modulus 2000 MPa) was used as a peelable base film. A body, a polarizing film, and a polarizing film with an adhesive layer were produced, and the obtained laminate and polarizing film were evaluated as described above.

[Comparative Example 1]
In (1. Preparation of laminate) in Example 1, the first resin contained in the first resin liquid was the resin X1 and no ultraviolet absorber was added, the thickness of the first resin layer was 4 μm, And except that the second resin layer was not formed, a laminate, a polarizing film, and a polarizing film with an adhesive layer were produced in the same manner as in Example 1, and the obtained laminate and polarizing film were evaluated as described above. rice field.

[Comparative Example 2]
The procedure was the same as in Comparative Example 1, except that an untreated OPP film (biaxially oriented polyolefin film; manufactured by Toray Industries, Ltd. "New type Torefan BO 40-2500", tensile modulus 2000 MPa) was used as the peelable base film. A laminate, a polarizing film, and a polarizing film with an adhesive layer were prepared by the above method, and the obtained laminate and polarizing film were evaluated as described above.

[Comparative Example 3]
In (1. Laminate production) in Example 1, the first resin layer was not formed, the second resin contained in the second resin liquid was the resin Y2, and the ultraviolet absorber was not added, and A laminate, a polarizing film, and a polarizing film with an adhesive layer were produced in the same manner as in Example 1, except that the thickness of the second resin layer was 4 μm, and the obtained laminate and polarizing film were evaluated as described above. rice field.

[Comparative Example 4]
The procedure was the same as in Comparative Example 3, except that an untreated OPP film (biaxially oriented polyolefin film; manufactured by Toray Industries, Ltd., "New Type Torefan BO 40-2500", tensile modulus of elasticity 2000 MPa) was used as the peelable base film. A laminate, a polarizing film, and a polarizing film with an adhesive layer were prepared by the above method, and the obtained laminate and polarizing film were evaluated as described above.

The results are shown in Tables 1 and 2. In the table below, the abbreviations have the following meanings.
UVA: UV absorber Re: In-plane retardation Rth: Thickness direction retardation "Si-PET": PET film (polyethylene terephthalate film; manufactured by Mitsubishi Chemical "MRV38" whose surface has been subjected to release treatment with silicone
"OPP": Untreated OPP film (biaxially oriented polyolefin film; manufactured by Toray "New type Torefan BO 40-2500"

As shown in Examples 1 to 7, in a laminate comprising a first resin layer containing a first resin having a predetermined storage modulus and a second resin layer containing a second resin having a predetermined storage modulus, It was confirmed that the occurrence of cracks in the polarizer can be suppressed when used in a polarizing film while reducing the surface unevenness of the second resin layer. On the other hand, as shown in Comparative Examples 1 and 2, in the laminate having only the first resin layer having a predetermined storage elastic modulus, it was difficult to alleviate the surface unevenness of the second resin layer. Moreover, in Comparative Example 1, it was confirmed that the adhesion between the base film and the resin layer was insufficient, so that the web handleability and the transferability deteriorated.

Moreover, as shown in Comparative Examples 3 and 4, it was confirmed that it is difficult to suppress polarizer cracks in a laminate having only a second resin layer having a predetermined storage elastic modulus. Moreover, it was confirmed that in Comparative Examples 3 and 4, sufficient humidification reliability was not obtained. This is presumed to be due to the fact that bonding failure occurred between the polarizer layer and the second resin layer when the second resin layer and the polarizer layer were bonded together. In particular, in Comparative Example 4, the smoothness of the surface of the second resin layer was lost due to the blocking between the second resin layer and the back surface of the substrate, so the influence of poor lamination between the polarizer layer and the second resin layer. is assumed to be large.

REFERENCE SIGNS LIST 100 laminate 101, 201, 301 and 401 first resin layer 102, 202, 302 and 402 second resin layer 20 peelable base film 200 laminate with adhesive layer 203, 403 adhesive layer 300 polarizing film 304 and 404 polarized light child layer 305 and 405 adhesive layer

Claims (18)

A first resin layer, a second resin layer and a peelable base film are provided in this order,
The first resin layer contains a first resin having a storage modulus of 650 MPa or more and 1700 MPa or less measured as a film having a thickness of 1 mm,
The laminate, wherein the second resin layer contains a second resin having a storage elastic modulus of 10 MPa or more and less than 650 MPa when measured as a film having a thickness of 1 mm. The laminate according to claim 1, wherein the thickness of the first resin layer is greater than 0 µm and no greater than 12 µm, and the thickness of the second resin layer is greater than 0 µm and no greater than 12 µm. 3. The laminate according to claim 1, wherein the sum of the thickness of said first resin layer and the thickness of said second resin layer is 12 [mu]m or less. The first resin and the second resin each independently have a water vapor transmission rate of 4 g/(m ² day) or less at 40° C. and 90% RH measured as a film having a thickness of 100 μm. Item 4. The laminate according to any one of Items 1 to 3. The first resin layer and the second resin layer each independently have an in-plane retardation of 5 nm or less and an absolute retardation value in the thickness direction of 5 nm or less. The laminate according to any one of the items. 6. The method according to any one of claims 1 to 5, wherein the first resin layer and the second resin layer each independently have a photoelastic constant of 5×10 ⁻¹³ cm ² /dyn or less. laminate. The laminate according to any one of claims 1 to 6, wherein the first resin and the second resin each independently contain a polymer having an alicyclic structure. In the second resin, the polymer having the alicyclic structure is a block copolymer hydride [E],
The block copolymer hydride [E] is a hydride of block copolymer [D],
The block copolymer [D] is a block copolymer consisting of polymer block [A] and polymer block [B] or polymer block [C],
Polymer block [A] is a polymer block mainly composed of repeating unit [I] derived from an aromatic vinyl compound,
The polymer block [B] is a polymer block mainly composed of repeating units [I] derived from an aromatic vinyl compound and repeating units [II] derived from a chain conjugated diene compound,
8. The laminate according to claim 7, wherein the polymer block [C] is a polymer block whose main component is the repeating unit [II] derived from a chain conjugated diene compound. Any one of claims 1 to 8, wherein at least one of the first resin layer and the second resin layer contains an ultraviolet absorber, and the content of the ultraviolet absorber is 2% by weight or more and 40% by weight or less. The laminate according to the item. Laminate according to any one of claims 1 to 9, wherein the second resin contains a plasticizer and/or a softener. 11. The laminate according to claim 10, wherein said plasticizer and/or softener is at least one selected from the group consisting of ester plasticizers and aliphatic hydrocarbon polymers. The laminate according to any one of claims 1 to 11, wherein at least one of the first resin and the second resin contains an organometallic compound. The laminate according to any one of claims 1 to 12, wherein the peelable base film has a tensile modulus of 2000 MPa or more. A first resin layer, a second resin layer and an adhesive layer are provided in this order,
The first resin layer contains a first resin having a storage modulus of 650 MPa or more and 1700 MPa or less measured as a film having a thickness of 1 mm,
The second resin layer contains a second resin having a storage modulus of 10 MPa or more and less than 650 MPa measured as a film having a thickness of 1 mm,
A laminate with an adhesive layer, wherein the adhesive layer has a thickness of 2 μm or more and 25 μm or less. A polarizer layer, a first resin layer and a second resin layer are provided in this order,
The first resin layer contains a first resin having a storage modulus of 650 MPa or more and 1700 MPa or less measured as a film having a thickness of 1 mm,
The polarizing film, wherein the second resin layer contains a second resin having a storage elastic modulus of 10 MPa or more and less than 650 MPa when measured as a film having a thickness of 1 mm. 16. The polarizing film according to claim 15, wherein the polarizer layer has a thickness of more than 1 [mu]m and not more than 12 [mu]m. A polarizing film with an adhesive layer, comprising the laminate with the adhesive layer according to claim 14 and a polarizer layer provided on the first resin layer of the laminate with the adhesive layer. A method for producing a polarizing film according to claim 15 or 16,
A step of applying a second resin liquid containing the second resin on a peelable base film and drying it to form a second resin layer;
a step of applying a first resin liquid containing the first resin onto the second resin layer and drying the liquid to form a first resin layer;
a step of bonding the polarizer layer and the first resin layer;
and a step of peeling the peelable base film from the second resin layer, in this order.

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