Laminate, laminate with adhesive layer, polarizing film, polarizing film with adhesive layer, and method for manufacturing a polarizing film

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]

[0001] 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 manufacturing a polarizing film. [Background technology]

[0002] In display devices such as liquid crystal displays and organic electroluminescent displays, polarizing films may be 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. In polarizer films, technology for arranging the resin layer on the polarizer layer by a transfer method is being developed (Patent Documents 1 and 2). [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] International Publication No. 2019 / 087806 [Patent Document 2] Japanese Patent Publication No. 2014-130298 [Overview of the project] [Problems that the invention aims to solve]

[0004] In polarizing films, if the protection of the polarizer layer is insufficient, cracks may occur in the polarizer layer due to temperature changes, for example. Therefore, the resin layer used as a protective layer is required to be able to suppress cracking of the polarizer layer.

[0005] Furthermore, the peelable base film used when forming the protective layer of the polarizer layer using a transfer method may have a fine uneven surface structure. An example of such an uneven structure is a minute uneven structure called a fisheye. When a resin liquid containing 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. If such a resin layer is used as a protective layer for a polarizing film, surface irregularities caused by the uneven structure of the base film may occur in the protective layer, potentially degrading the display quality of a display device using it.

[0006] The present invention was conceived in view of the above-mentioned problems, and aims to provide a laminate that can be used as a resin layer (protective layer) capable of suppressing cracks in the polarizer layer of a polarizing film, and that can mitigate the occurrence of surface irregularities in the resin layer caused by the uneven structure of the base film when the resin layer is peeled off from a peelable base film, a laminate with an adhesive layer using the same, a polarizing film, a polarizing film with an adhesive layer, and a method for manufacturing a polarizing film. [Means for solving the problem]

[0007] The inventors diligently studied to solve the aforementioned problems. As a result, the inventors discovered that the above problems can be solved by adjusting the storage modulus of the resins contained in the first resin layer and the second resin layer, respectively, in a laminate comprising a first resin layer, a second resin layer, and a peelable base film in that order, and thus completed the present invention. In other words, the present invention includes the following:

[0008] [1] A laminate comprising a first resin layer, a second resin layer, and a peelable base film in this order, wherein the first resin layer contains a first resin having a storage modulus of 650 MPa or more and 1700 MPa or less as measured as a 1 mm thick film, and the second resin layer contains a second resin having a storage modulus of 10 MPa or more and less than 650 MPa as measured as a 1 mm thick film. 〔2〕 The laminate according to 〔1〕, wherein the thickness of the first resin layer is greater than 0 μm and not more than 12 μm, and the thickness of the second resin layer is greater than 0 μm and not more than 12 μm. 〔3〕 The laminate according to 〔1〕 or 〔2〕, wherein the sum of the thicknesses of the first resin layer and the second resin layer is not more than 12 μm. 〔4〕 The first resin and the second resin are each independently a film having a thickness of 100 μm and having a water vapor transmission rate at 40 °C and 90% RH of 4 g / (m 2 ·day) or less, which is the laminate according to any one of 〔1〕 to 〔3〕. 〔5〕 The laminate according to any one of 〔1〕 to 〔4〕, wherein the in-plane retardation of the first resin layer and the second resin layer is each independently 5 nm or less, and the absolute value of the retardation in the thickness direction is 5 nm or less. 〔6〕 The laminate according to any one of 〔1〕 to 〔5〕, wherein the photoelastic constant of the first resin layer and the second resin layer is each independently 5 × 10 -13 cm 2 / dyn or less. 〔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], the block copolymer hydride [E] is a hydride of a block copolymer [D], the block copolymer [D] is a block copolymer composed of a polymer block [A] and a polymer block [B] or a polymer block [C], the polymer block [A] is a polymer block mainly composed of a repeating unit [I] derived from an aromatic vinyl compound, the polymer block [B] is a polymer block mainly composed of a repeating unit [I] derived from an aromatic vinyl compound and a repeating unit [II] derived from a chain conjugated diene compound, and the polymer block [C] is a polymer block mainly composed of a repeating unit [II] derived from a chain conjugated diene compound, which is the laminate according to 〔7〕. 〔9〕The laminate according to any one of 〔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. 〔10〕The laminate according to any one of 〔1〕 to 〔9〕, wherein the second resin contains a plasticizer and / or a softening agent. 〔11〕The laminate according to 〔10〕, wherein the plasticizer and / or the softening agent 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 tensile elastic modulus of the peelable base film is 2000 MPa or more. 〔14〕A laminate with an adhesive layer, comprising a first resin layer, a second resin layer, and an adhesive layer in this order, wherein the first resin layer contains a first resin having a storage elastic modulus of 650 MPa or more and 1700 MPa or less as measured for a film with a thickness of 1 mm, 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 for 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. 〔15〕A polarizing film, comprising a polarizer layer, a first resin layer, and a second resin layer in this order, wherein the first resin layer contains a first resin having a storage elastic modulus of 650 MPa or more and 1700 MPa or less as measured for a film with a thickness of 1 mm, and 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 for a film with a thickness of 1 mm. 〔16〕The polarizing film according to 〔15〕, wherein the thickness of the polarizer layer is greater than 1 μm and 12 μm or less. 〔17〕A polarizing film with an adhesive layer, having 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] A method for manufacturing a polarizing film according to

[15] or

[16] , comprising in this order: applying a second resin liquid containing the second resin onto a peelable base film and drying it to form a second resin layer; applying a first resin liquid containing the first resin onto the second resin layer and drying it to form a first resin layer; laminating a polarizer layer with the first resin layer; and peeling the peelable base film from the second resin layer. [Effects of the Invention]

[0009] According to the present invention, a laminate can be used as a resin layer capable of suppressing cracks in the polarizer layer of a polarizing film, and when the resin layer is peeled off from a peelable base film, the occurrence of surface irregularities in the resin layer caused by the uneven structure of the base film can be mitigated. The present invention also provides a laminate with an adhesive layer using the same, a polarizing film, a polarizing film with an adhesive layer, and a method for manufacturing a polarizing film. [Brief explanation of the drawing]

[0010] [Figure 1] Figure 1 is a schematic cross-sectional view showing a laminate according to one embodiment of the present invention. [Figure 2] Figure 2 is a schematic cross-sectional view showing a laminate with an adhesive layer according to one embodiment of the present invention. [Figure 3] Figure 3 is a schematic cross-sectional view showing a polarizing film according to one embodiment of the present invention. [Figure 4] Figure 4 is a schematic cross-sectional view showing a polarizing film with an adhesive layer according to one embodiment of the present invention. [Modes for carrying out the invention]

[0011] The present invention will be described in detail below with reference to embodiments and examples. However, the present invention is not limited to the embodiments and examples shown below, and may be implemented with modifications as appropriate without departing from the scope of the claims and equivalents of the present invention.

[0012] In the following description, "long" refers to a shape that is typically five times or more in length than its width, preferably ten times or more in length, and specifically a shape that is long enough to be rolled up for storage or transport. There is no particular upper limit to the ratio of length to width, but it may be, for example, 100,000 times or less.

[0013] In the following description, adhesives and tacks are distinguished by their shear storage modulus unless otherwise specified. Specifically, unless otherwise specified, adhesives refer to materials whose shear storage modulus at 23°C is between 1 MPa and 500 MPa after energy ray irradiation or heat treatment. Unless otherwise specified, tacks refer to materials whose shear storage modulus at 23°C is less than 1 MPa.

[0014] In the following explanation, the in-plane retardation Re of a layer is given by the value Re = (nx - ny) × d unless otherwise specified. Also, the thickness-direction retardation Rth of a layer is given by the value Rth = [{(nx + ny) / 2} - nz] × d unless otherwise specified. Here, nx represents the refractive index in the direction perpendicular to the thickness direction of the layer (in-plane direction) that gives the maximum refractive index. ny represents the refractive index in the in-plane direction of the layer that is perpendicular to the direction of nx. 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 specified.

[0015] In the following description, unless otherwise specified, (meth)acrylic resin includes acrylic resin, methacrylic resin, and combinations thereof. Furthermore, unless otherwise specified, (meth)acrylic acid includes acrylic acid, methacrylic acid, and combinations thereof.

[0016] In the following description, unless otherwise specified, "plate," "layer," and "film" may refer to rigid members, or they may refer to flexible members such as a resin film.

[0017] [1. Laminate] Figure 1 is a schematic cross-sectional view showing a laminate 100 according to one embodiment of the present invention. As shown in Figure 1, the laminate 100 comprises a first resin layer 101, a second resin layer 102, and a peelable base film 20 in this order in the thickness direction.

[0018] In the laminate 100, the second resin layer 102 is typically provided directly on the base film 20. Furthermore, in the laminate 100, the first resin layer 101 is typically provided directly on the second resin layer 102. Here, "directly" provided to one layer means that one layer and another are in contact, and there are no other layers between them.

[0019] The first resin layer 101 contains a first resin whose storage modulus, measured as a 1 mm thick film, is between 650 MPa and 1700 MPa. The second resin layer 102 contains a second resin whose storage modulus, measured as a 1 mm thick film, is between 10 MPa and 650 MPa. In the following description, unless otherwise specified, "storage modulus measured as a 1 mm thick film" may be simply referred to as "storage modulus."

[0020] According to the present invention, the second resin layer can be made flexible by including a second resin having a storage modulus of 10 MPa or more and less than 650 MPa. Therefore, even if surface irregularities caused by the uneven structure of the base film occur immediately after peeling the second resin layer from the base film, the flexibility of the second resin layer can reduce the height difference of the surface irregularities over time, thereby mitigating the surface irregularities of the second resin layer.

[0021] Furthermore, by including a first resin having a storage modulus of 650 MPa to 1700 MPa in the first resin layer, rigidity can be imparted to the first resin layer. Therefore, when the laminated portion of the first and second resin layers is used as a protective layer for the polarizer layer in a polarizing film, cracking of the polarizer layer due to temperature changes can be suppressed.

[0022] [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.

[0023] [1.1.1. Daiichi Resin] The first resin is a resin whose storage modulus, measured as a 1mm thick film, is between 650 MPa and 1700 MPa.

[0024] The storage modulus of the first resin is typically 650 MPa or higher, preferably 700 MPa or higher, more preferably 750 MPa or higher, and typically 1700 MPa or lower, preferably 1000 MPa or lower, more preferably 900 MPa or lower. This is because, when the storage modulus of the first resin is above the lower limit, cracks in the polarizer layer due to temperature changes can be suppressed when the laminated portion of the first and second resin layers is used as a protective layer in a polarizing film, and when the storage modulus of the first resin layer is below the upper limit, good flexibility can be imparted to the polarizing film while suppressing cracks in the polarizer layer when used as a protective layer in a polarizing film.

[0025] The storage modulus of the first resin can be measured by the following measurement method. A 1mm thick measuring film is prepared by molding the first resin. A fusion press method can be used for molding. Then, the storage modulus of the prepared measuring film is measured using a dynamic viscoelasticity measuring device. This measurement is performed 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.

[0026] The first resin preferably has a water vapor transmission rate within a predetermined range, measured as a 100 μm thick film at 40°C and 90% RH. Specifically, the water vapor transmission rate of the first resin is preferably 4.0 g / (m²). 2 • day) or less, more preferably 3.0 g / (m 2 • day) or less, particularly preferably 2.0 g / (m 2 It is less than or equal to (day). The lower limit is ideally 0 g / (m 2·day) and 0.1g / (m 2 It may be more than (day). By forming the first resin layer with a first resin having a water vapor permeability within the above range, the humidification reliability of the polarizing film using this can be made particularly good. Specifically, since the moisture permeability of the first resin layer can be made sufficiently low, it is possible to suppress water vapor from reaching the polarizer layer and effectively suppress the decrease in polarization degree due to water vapor.

[0027] The water vapor transmission rate of the first resin can be measured by the following measurement method. A 100 μm thick measurement film is prepared by molding the first resin. A hot fusion press method can be used for molding. Subsequently, the water vapor transmission rate of the prepared measurement film is measured under conditions of 40°C and 90% RH. This measurement is performed using a water vapor transmission rate measuring device in accordance with JIS K 7129 B method.

[0028] The first resin typically contains a polymer. Furthermore, the polymer contained in the first resin is typically thermoplastic. Because the polymer is thermoplastic, the first resin may also be thermoplastic.

[0029] Examples of polymers included in the first resin include polyester, acrylic polymers, and polymers containing alicyclic structures. These polymers may be used individually or in combination of two or more in any ratio. Among these, polymers containing alicyclic structures are preferred from the viewpoint of lowering the water vapor permeability of the first resin layer.

[0030] Polymers containing alicyclic structures have repeating units that contain alicyclic structures. Polymers containing alicyclic structures typically have low water vapor permeability. Therefore, when a first resin layer is formed using a first resin containing a polymer with an alicyclic structure, it is possible to effectively suppress water vapor from reaching the polarizer layer.

[0031] Polymers containing alicyclic structures may contain alicyclic structures in the main chain, in the side chains, or in both the main chain and side chains. Among these, polymers containing alicyclic structures in at least the main chain are preferred from the viewpoint of mechanical strength and heat resistance.

[0032] Examples of alicyclic structures include saturated alicyclic hydrocarbon (cycloalkane) structures and unsaturated alicyclic hydrocarbon (cycloalkene, cycloalkyne) structures. Among these, cycloalkane and cycloalkene structures are preferred from the viewpoint of mechanical strength and heat resistance, and cycloalkane structures are particularly preferred.

[0033] 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 15 or less per alicyclic structure. 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.

[0034] In polymers containing alicyclic structures, the proportion of repeating units containing alicyclic structures can be appropriately selected depending on the intended use. The proportion of repeating units containing alicyclic structures in a polymer containing alicyclic structures is preferably 55% by weight or more, more preferably 70% by weight or more, and particularly preferably 90% by weight or more. When the proportion of repeating units containing alicyclic structures in a polymer containing alicyclic structures falls within this range, the transparency and heat resistance of the first resin are good.

[0035] Examples of polymers containing alicyclic structures include norbornene polymers, monocyclic olefin polymers, cyclic conjugated diene polymers, vinyl alicyclic hydrocarbon polymers, and their hydrides. Among these, norbornene polymers and their hydrides are preferred because they have good transparency and moldability, and are easy to adjust to the desired storage modulus.

[0036] Examples of norbornene polymers and their hydrides include ring-opening polymers of monomers having a norbornene structure and their hydrides; and addition polymers of monomers having a norbornene structure and their hydrides. Examples of ring-opening polymers of monomers having a norbornene structure include ring-opening homopolymers of one type of monomer having a norbornene structure, ring-opening copolymers of two or more types of monomers having a norbornene structure, and ring-opening copolymers of monomers having a norbornene structure and any monomer 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, addition copolymers of two or more types of monomers having a norbornene structure, and addition copolymers of monomers having a norbornene structure and any monomer copolymerizable therewith. Examples of these polymers include those disclosed in Japanese Patent Application Publication No. 2002-321302, etc.

[0037] Specific examples of norbornene polymers and their hydrides include "Zeonor" manufactured by Zeon Corporation; "Arton" manufactured by JSR Corporation; and "TOPAS" manufactured by TOPAS Advanced Polymers.

[0038] 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, preferably 100,000 or less, more preferably 80,000 or less, and particularly preferably 50,000 or less. When the weight-average molecular weight is within this range, the mechanical strength and moldability of the first resin are highly balanced.

[0039] The molecular weight distribution (Mw / Mn) of the polymer contained in the first resin is preferably 1.2 or higher, more preferably 1.5 or higher, particularly preferably 1.8 or higher, preferably 3.5 or lower, more preferably 3.0 or lower, and particularly preferably 2.7 or lower. Here, Mn represents the number-average molecular weight. When the molecular weight distribution is above the lower limit of the above range, the productivity of the polymer can be increased and manufacturing costs can be suppressed. Also, when the molecular weight distribution is below the upper limit of the above range, the amount of low molecular weight components is reduced, which can suppress relaxation during exposure to high temperatures and improve the stability of the first resin layer.

[0040] The weight-average molecular weight (Mw) and number-average molecular weight (Mn) mentioned above can be measured using gel permeation chromatography (GPC). Examples of solvents used in GPC include cyclohexane, toluene, and tetrahydrofuran. When using GPC, the weight-average molecular weight can be measured, for example, as the relative molecular weight in terms of polyisoprene or polystyrene.

[0041] The glass transition temperature of the polymer contained in the first resin is preferably 100°C or higher, more preferably 110°C or higher, even more preferably 120°C or higher, preferably 170°C or lower, more preferably 160°C or lower, and even more preferably 150°C or lower. When the glass transition temperature of the polymer is within the above range, the durability of the polarizing film in high-temperature environments can be increased. The glass transition temperature can be measured using a differential scanning calorimeter (DSC) by raising the temperature at 10°C / min.

[0042] The amount of polymer contained in the first resin is preferably 70% by weight or more, more preferably 80% by weight or more, and even more preferably 85% by weight or more, relative to 100% by weight of the first resin, and is usually 99% by weight or less, preferably 96% by weight or less, and more preferably 93% by weight or less. When the amount of polymer contained in the first resin is within the above range, the occurrence of cracks in the polarizer layer due to temperature changes can be effectively suppressed.

[0043] The first resin may further contain any components in combination with the above-described polymer. Examples of the optional components include a moisture absorbent; a dispersant; an organometallic compound; stabilizers such as an antioxidant and a light stabilizer; a resin modifier such as a lubricant; a colorant such as a dye and a pigment; an antistatic agent; and the like. The optional components may be used alone or in combination of two or more kinds in any ratio.

[0044] The first resin preferably further contains an organometallic compound in combination with the polymer. By containing the organometallic compound, the adhesion between the first resin layer and the polarizer layer described later can be enhanced.

[0045] The 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. Examples of the organometallic compound include an organosilicon compound, an organotitanium compound, an organoaluminum compound, and an organozirconium compound. Among these, an organosilicon compound, an organotitanium compound, and an organozirconium compound are preferable, and an organosilicon compound is more preferable because of its excellent reactivity with components such as polyvinyl alcohol contained in the polarizer layer. The organometallic compound may be used alone or in combination of two or more kinds in any ratio.

[0046] Examples of the organometallic compound include an organosilicon compound 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 group selected from the group consisting of 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 an organic group having 1 to 10 carbon atoms, and a represents an integer of 0 to 4.)

[0047] In formula (1), R 1Preferred examples include epoxy groups, amino groups, thiol groups, isocyanate groups, vinyl groups, acrylic groups, and alkyl groups having 1 to 8 carbon atoms. Also, in equation (1), R 2 Preferred examples include hydrogen atoms, vinyl groups, aryl groups, acrylic groups, alkyl groups with 1 to 8 carbon atoms, and -CH2OC. n H 2n+1 Examples include (where n represents an integer from 1 to 4).

[0048] Examples of organosilicon compounds include epoxy-based organosilicon compounds such as 3-glycidoxypropyltrimethoxysilane and 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane; amino-based organosilicon compounds such as 3-aminopropyltrimethoxysilane and N-2-(aminoethyl)-3-aminopropyltrimethoxysilane; isocyanurate-based organosilicon compounds such as tris-(trimethoxysilylpropyl)isocyanurate; mercapto-based organosilicon compounds such as 3-mercaptopropyltrimethoxysilane; and isocyanate-based organosilicon compounds such as 3-isocyanatetopropyltriethoxysilane.

[0049] Examples of organotitanium compounds include titanium alkoxides such as tetraisopropyl titanate, titanium chelates such as titanium acetylacetonate, and titanium acylates such as titanium isostearate.

[0050] Examples of organozirconium compounds include zirconium alkoxides such as n-propyl zirconate, zirconium chelates such as zirconium tetraacetylacetonate, and zirconium acylates such as zirconium stearate.

[0051] Examples of organoaluminum compounds include aluminum alkoxides such as aluminum secondary butoxides, and aluminum chelates such as aluminum trisacetylacetonate.

[0052] The amount of organometallic compound per 100 parts by weight of polymer contained in the first resin is preferably 0.005 parts by weight or more, more preferably 0.01 parts by weight or more, particularly preferably 0.03 parts by weight or more, preferably 1.0 part by weight or less, and more preferably 0.5 parts by weight or less. When the proportion of organometallic compound is within the above range, the adhesion between the first resin layer and the polarizer layer can be increased.

[0053] [1.1.2. UV absorbers] In this embodiment, it is preferable that at least one of the first resin layer and the second resin layer contains an ultraviolet absorber. This is because when the first and second resin layers are used as protective layers in the polarizing film, degradation of the polarizer layer due to ultraviolet light can be suppressed. If the second resin layer does not contain an ultraviolet absorber, it is preferable that the first resin layer contains an ultraviolet absorber.

[0054] Examples of UV absorbers include triazine-based UV absorbers, benzophenone-based UV absorbers, benzotriazole-based UV absorbers, and acrylonitrile-based UV absorbers. Preferred UV absorbers include benzotriazole-based UV absorbers such as 2-(2H-benzotriazole-2-yl)-4-(1,1,3,3-tetramethylbutyl)phenol, 2-(2H-benzotriazole-2-yl)-4,6-bis(1-methyl-1-phenylethyl)phenol, and 2-(2'-hydroxy-3'-t-butyl-5'-merylphenyl)-5-chlorobenzotriazole. UV absorbers may be used individually or in combination of two or more types.

[0055] 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, preferably 40% by weight or less, and more preferably 30% by weight or less.

[0056] [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 even more preferably 7 μm or less. By having the thickness of the first resin layer within the above range, a thin resin layer can be placed as a protective layer relative to the polarizer layer.

[0057] The first resin layer preferably has low optical anisotropy in both the in-plane direction and the thickness direction, and preferably has optical isotropy. Therefore, it is preferable that the in-plane retardation of the first resin layer be 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. Furthermore, the retardation in the thickness direction 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, even more preferably -3 nm or more, particularly preferably -2 nm or more, 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.

[0058] The photoelastic constant of the first resin layer is preferably within a specific range. Specifically, the smaller the photoelastic constant of the first resin layer, the better, 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 It is less than or equal to / dyn. Ideally, it should be 0.0 × 10⁻⁶ -13 cm 2The value is / 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 calculated from the birefringence that occurs when stress is applied to the first resin layer. For specific measurement methods, the method described in the examples can be adopted.

[0059] 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 more, more preferably 85% or more, and particularly preferably 90% or more. The total light transmittance can be measured using an ultraviolet-visible spectrometer in the wavelength range of 400 nm to 700 nm.

[0060] 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%. The haze can be measured using a haze meter in accordance with JIS K7361-1997.

[0061] [1.2. Second resin layer] The second resin layer is a layer containing the first resin, which has a storage modulus of 10 MPa or more and less than 650 MPa.

[0062] [1.2.1.Second resin] The second resin is a resin whose storage modulus, measured as a 1mm thick film, is between 10 MPa and 650 MPa.

[0063] The storage modulus of the second resin is typically 10 MPa or more, preferably 50 MPa or more, more preferably 150 MPa or more, and typically less than 650 MPa, preferably 600 MPa or less, and more preferably 550 MPa or less. This is because having the storage modulus of the second resin within the above range suppresses surface irregularities of the second resin layer caused by the base film when peeling the second resin layer from the base film. The method for measuring the storage modulus of the second resin may be the same as the method for measuring the storage modulus of the first resin.

[0064] The second resin preferably has a water vapor transmission rate within a predetermined range, measured as a 100 μm thick film at 40°C and 90% RH. Specifically, the water vapor transmission rate of the first resin is preferably 4.0 g / (m²). 2 • day) or less, more preferably 3.0 g / (m 2 • day) or less, particularly preferably 2.0 g / (m 2 It is less than or equal to (day). The lower limit is ideally 0 g / (m 2 • day) or more, and 0.1 g / (m 2 It may be more than (day). 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.

[0065] The polymer contained in the second resin is typically thermoplastic. Because the polymer is thermoplastic, the second resin may also be thermoplastic.

[0066] The second resin preferably contains a polymer that includes an alicyclic structure. Examples of polymers containing alicyclic structures that the second resin may include norbornene polymers, monocyclic olefin polymers, cyclic conjugated diene polymers, vinyl alicyclic hydrocarbon polymers, and their hydrides, as well as 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 the desired storage modulus.

[0067] A hydride of a vinyl aromatic hydrocarbon polymer means a hydride of a polymer containing repeating units [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 manufacturing method.

[0068] Examples of aromatic vinyl compounds corresponding to the repeating unit [I] include styrene; styrenes having C1-C6 alkyl groups as substituents, such as α-methylstyrene, 2-methylstyrene, 3-methylstyrene, 4-methylstyrene, 2,4-dimethylstyrene, 2,4-diisopropylstyrene, 4-t-butylstyrene, and 5-t-butyl-2-methylstyrene; styrenes having halogen atoms as substituents, such as 4-chlorostyrene, dichlorostyrene, and 4-monofluorostyrene; styrenes having C1-C6 alkoxy groups as substituents, such as 4-methoxystyrene; styrenes having aryl groups as substituents, such as 4-phenylstyrene; vinylnaphthalenes such as 1-vinylnaphthalene and 2-vinylnaphthalene; and the like. These may be used individually or in combination of two or more in any ratio. Among these, aromatic vinyl compounds that do not contain polar groups, such as styrene and styrenes having C1-C6 alkyl groups as substituents, are preferred because they can reduce hygroscopicity, and styrene is particularly preferred due to its ease of industrial availability.

[0069] The hydride of a polymer containing repeating units [I] derived from an aromatic vinyl compound is preferably a specific block copolymer hydride [E]. The block copolymer hydride [E] is a hydride of block copolymer [D]. Block copolymer [D] is a polymer block consisting of polymer block [A] and polymer block [B] or polymer block [C]. Polymer block [A] is a polymer block mainly composed of repeating units [I] derived from an aromatic vinyl compound. 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-like conjugated diene compound. Polymer block [C] is a polymer block mainly composed of repeating units [II] derived from a chain-like conjugated diene compound. Here, "main component" refers to a component that makes up 50% by weight or more of the polymer block. Repeating units derived from a chain-like conjugated diene compound mean repeating units having a structure obtained by polymerizing a chain-like conjugated diene compound.

[0070] Examples of chain-like conjugated diene compounds corresponding to the repeating unit [II] include 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, and 1,3-pentadiene. These may be used individually or in combination of two or more in any ratio. The chain-like conjugated diene compounds may be linear or branched.

[0071] Hydrogenated vinyl aromatic hydrocarbon polymers are substances obtained by hydrogenating the unsaturated bonds of the vinyl aromatic hydrocarbon polymer. Here, the unsaturated bonds of the vinyl aromatic hydrocarbon polymer to be hydrogenated include both the carbon-carbon unsaturated bonds of the main chain and side chains of the polymer, as well as the carbon-carbon unsaturated bonds of the aromatic ring.

[0072] Hydrides can be produced, for example, by hydrogenating 90% or more of the unsaturated bonds of a vinyl aromatic hydrocarbon polymer in a solution of the polymer in the presence of a hydrogenation catalyst containing a transition metal such as nickel or palladium.

[0073] 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, preferably 100,000 or less, more preferably 80,000 or less, and particularly preferably 50,000 or less. When the weight-average molecular weight is within this range, the mechanical strength and moldability of the second resin layer are highly balanced.

[0074] The molecular weight distribution (Mw / Mn) of the polymer contained in the second resin is preferably 1.2 or higher, more preferably 1.5 or higher, particularly preferably 1.8 or higher, preferably 3.5 or lower, more preferably 3.0 or lower, and particularly preferably 2.7 or lower. Here, Mn represents the number-average molecular weight. By setting the molecular weight distribution above the lower limit of the above range, the productivity of the polymer can be increased and manufacturing costs can be suppressed. Furthermore, by setting it below the upper limit, the amount of low-molecular-weight components is reduced. As a result, relaxation of the resin layer during high-temperature exposure can be suppressed, and the stability of the second resin layer can be improved.

[0075] The method for measuring the weight-average molecular weight (Mw) and number-average molecular weight (Mn) described above may be the same as the method for measuring the weight-average molecular weight (Mw) and number-average molecular weight (Mn) of the first resin.

[0076] When the second resin contains a block copolymer hydride [E], it is possible to provide the polyethylene terephthalate film, which serves as a peelable base film, with the second resin layer, with appropriate peelability that facilitates peeling during transfer and prevents peeling at unintended timings. Therefore, the web handling properties of the laminate can be improved. Furthermore, since the peelability between the base film and the second resin layer can be improved, for example, a resin with low adhesion to the base film can be selected as the resin included in the first resin layer.

[0077] The second resin may contain any additional components in combination with the polymer described above. Examples of optional components include plasticizers and / or softeners; organometallic compounds; stabilizers such as antioxidants and light stabilizers; resin modifiers such as lubricants; colorants such as dyes and pigments; and antistatic agents. These components may be used individually or in combination of two or more in any ratio.

[0078] Furthermore, it is preferable that the second resin contains a plasticizer and / or a softener (plasticizer or softener, or both) as an optional component. By including a plasticizer and / or a softener, the storage modulus of the second resin can be easily adjusted. In addition, the moldability (e.g., extensibility) of the second resin can be improved.

[0079] As plasticizers and / or softeners, those that can be uniformly dissolved or dispersed in the second resin may be used. Specific examples of plasticizers and / or softeners include ester-based plasticizers such as polyhydric alcohol ester-based plasticizers and polyhydric carboxylic acid ester-based plasticizers; phosphate ester-based plasticizers; carbohydrate ester-based plasticizers; and other polymer softeners. A polyhydric alcohol ester-based plasticizer refers to an ester-based plasticizer composed of a polyhydric alcohol and a monohydric carboxylic acid. Similarly, a polyhydric carboxylic acid ester-based plasticizer refers to an ester-based plasticizer composed of a polyhydric carboxylic acid and a monohydric alcohol.

[0080] Examples of polyhydric alcohols used as raw materials for ester-based plasticizers are not particularly limited, but ethylene glycol, glycerin, and trimethylolpropane are preferred.

[0081] Examples of polyhydric alcohol ester plasticizers include ethylene glycol ester plasticizers, glycerin ester plasticizers, and other polyhydric alcohol ester plasticizers.

[0082] Examples of polycarboxylic acid ester plasticizers include dicarboxylic acid ester plasticizers and other polycarboxylic acid ester plasticizers.

[0083] Examples of phosphate ester plasticizers include alkyl phosphates such as triacetyl phosphate and tributyl phosphate; cycloalkyl phosphates such as tricyclopentyl phosphate and cyclohexyl phosphate; and aryl phosphates such as triphenyl phosphate and tricresyl phosphate.

[0084] Examples of carbohydrate ester-based plasticizers include glucose pentaacetate, glucose pentapropionate, glucose pentabutyrate, saccharose octaacetate, and saccharose octabenzoate, with saccharose octaacetate being the most preferred of these.

[0085] Examples of polymer softeners include aliphatic hydrocarbon polymers, alicyclic hydrocarbon polymers, acrylic polymers such as ethyl polyacrylate, polymethyl methacrylate, copolymers of methyl methacrylate and 2-hydroxyethyl methacrylate, copolymers of methyl methacrylate, methyl acrylate and 2-hydroxyethyl methacrylate; vinyl polymers such as polyvinyl isobutyl ether and poly-N-vinylpyrrolidone; styrene polymers such as polystyrene and poly-4-hydroxystyrene; polyesters such as polybutylene succinate, polyethylene terephthalate, and polyethylene naphthalate; polyethers such as polyethylene oxide and polypropylene oxide; and polyamides, polyurethanes, and polyureas.

[0086] Specific examples of aliphatic hydrocarbon polymers include low molecular weight polymers such as polyisobutylene, polybutene, poly-4-methylpentene, poly-1-octene, and ethylene-α-olefin copolymers, and their hydrides; and low molecular weight polymers such as polyisoprene and polyisoprene-butadiene copolymers, and their hydrides. From the viewpoint of easy uniform dissolution or dispersion in cycloolefin resins, the aliphatic hydrocarbon polymer is preferably number-average molecular weight of 300 to 5,000.

[0087] These polymer softeners may be homopolymers consisting of one type of repeating unit, or copolymers having multiple repeating structures. Furthermore, the above polymer softeners may be used individually, or two or more types may be used in any ratio.

[0088] As the plasticizer and / or softener, one or more selected from the group consisting of ester-based plasticizers and aliphatic hydrocarbon polymers are particularly preferred because they exhibit excellent compatibility with the components contained in the first resin.

[0089] The total amount of plasticizer and softener per 100 parts by weight of polymer in the second resin is preferably 5 parts by weight or more, more preferably 10 parts by weight or more, even more preferably 20 parts by weight or more, 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 when the total ratio of plasticizer and softener in the second resin is within the above range, the storage modulus of the second resin can be easily adjusted to a desired range. Furthermore, the moldability of the second resin can be improved.

[0090] The second resin preferably contains an organometallic compound as an optional component. This is because the inclusion of an organometallic compound in the second resin improves the adhesion between the second resin layer and the adhesive layer. Furthermore, it improves the adhesion when the second resin layer is placed, for example, on a glass component of a display device, without the need for the adhesive layer.

[0091] The types and content of organometallic compounds that the second resin may contain may be the same as those described for the types and content of organometallic compounds that the first resin may contain.

[0092] [1.2.2. UV absorbers] In this embodiment, it is preferable that at least one of the first resin layer and the second resin layer contains an ultraviolet absorber. Therefore, if the first resin layer does not contain an ultraviolet absorber, it is preferable that the second resin layer contains an ultraviolet absorber.

[0093] 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, preferably 40% by weight or less, and more preferably 30% by weight or less. The type of ultraviolet absorber contained in the second resin layer may be the same as that described in the section [1.1.2. Ultraviolet Absorber] of [1.1. First Resin Layer].

[0094] [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, preferably 12 μm or less, more preferably 10 μm or less, and even more preferably 7 μm or less. By having the thickness of the second resin layer within the above range, a thin resin layer can be placed as a protective layer relative to the polarizer layer.

[0095] The second resin layer preferably has low optical anisotropy in both the in-plane direction and the thickness direction, and preferably has optical isotropy. Therefore, it is preferable that the in-plane retardation of the second resin layer be 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. Furthermore, the retardation in the thickness direction 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, even more preferably -3 nm or more, particularly preferably -2 nm or more, 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.

[0096] The photoelastic constant of the second resin layer is preferably within a specific range. Specifically, the smaller the photoelastic constant of the second resin layer, the better, 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 It is less than or equal to / dyn. Ideally, it should be 0.0 × 10⁻⁶ -13 cm 2 The value is / 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.

[0097] The second 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 second resin layer is high. Specifically, the total light transmittance of the second resin layer is preferably 80% or more, more preferably 85% or more, and particularly preferably 90% or more.

[0098] 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%.

[0099] The measurement methods for the photoelastic constant, total light transmittance, and haze of the second resin layer may be the same as those described in [1.1.3. Physical Properties of the First Resin Layer].

[0100] [1.3. Laminated section of the first resin layer and the second resin layer] The laminate according to the present invention includes a first resin layer and a second resin layer, each containing a resin having a predetermined storage modulus. This allows the laminated portion of the first and second resin layers to be used as a resin layer capable of suppressing cracks in the polarizer layer of a polarizing film, and mitigates the occurrence of surface irregularities in the resin layer caused by the uneven structure of the base film when the resin layer is peeled off from a peelable base film. In this embodiment, it is preferable that the difference between the storage modulus of the first resin in the first resin layer and the storage modulus of the second resin in the second resin layer is 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, even more preferably 300 MPa or more, preferably 1000 MPa or less, preferably 800 MPa or less, and even more preferably 700 MPa or less. This is because setting the storage moduli of the first and second resins within the above range makes it easier to achieve the effects of suppressing polarizer cracks and mitigating surface irregularities in the second resin layer as described above.

[0101] The laminated portion of the first and second resin layers in the laminate can function as a protective layer for the polarizer layer in the polarizing film. The combined thickness of the first and second resin layers is preferably 12 μm or less, more preferably 10 μm or less. However, the lower limit of the combined thickness of the first and second resin layers can be, for example, 4 μm.

[0102] [1.4. Peelable base film] A peelable base film is used in a laminate to support the first and second resin layers. "Peelable" means that the second resin layer, which is positioned on the surface of the base film, can be peeled off.

[0103] 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 higher, more preferably 2500 MPa or higher, more preferably 5000 MPa or lower, and more preferably 4500 MPa or lower. By having the tensile modulus of the base film above the lower limit, good adhesion between the base film and the second resin layer can be achieved, and by having the tensile modulus below the upper limit, peeling between the base film and the second resin layer can be suppressed while preventing curling at the edges of the laminate. The tensile modulus can be measured using a tensile testing machine (manufactured by Instron Japan Company Limited, product name "Electromechanical Universal Material Testing Machine (5564)") in accordance with JIS K7127.

[0104] Typically, a resin film made of polyethylene terephthalate, polyethylene, polypropylene, or other resins is used as the base film. When using an ultraviolet-curing adhesive to bond the polarizer layer and the first resin layer, a resin film with low UV-B absorption is preferred. Unless otherwise specified, "UV-B" refers to light with a wavelength of 280 nm to 315 nm. The surface of this base film may be treated with a release agent to facilitate the removal of the second resin layer.

[0105] As a release treatment, for example, a process of forming a release agent layer on the surface of the base film is used. Examples of release agents include silicone-based release agents such as polydimethylsiloxane, fluorine-based release agents such as alkyl fluoride, and long-chain alkyl-based release agents. Among these, silicone-based release agents are preferred because they have good release properties and processability.

[0106] [1.5. Applications of laminates] The laminate of the present invention can be used as a transfer laminate when forming a resin layer as a protective layer on a polarizer layer by a transfer method in a method for manufacturing a polarizing film.

[0107] [2. Laminate with adhesive layer] Figure 2 is a schematic cross-sectional view of a laminated body 200 with an adhesive layer according to one embodiment of the present invention. As shown in Figure 2, the laminated body 200 with an adhesive layer comprises a first resin layer 201, a second resin layer 202, and an adhesive layer 203 in this order in the thickness direction. The laminated body 200 with an adhesive layer has a thickness of 2 μm or more and 25 μm or less.

[0108] The first resin layer and the second resin layer may be the same as those described in the section [1. Laminate] above.

[0109] The adhesive layer is a layer provided on the second resin layer. The adhesive layer 203 is usually provided directly on the second resin layer 202, as shown in Figure 2.

[0110] The adhesive layer, utilizing its adhesive strength, can bond the laminated portion of the first and second resin layers to other optical components. Therefore, for example, when a polarizer layer is placed on the first resin layer to form a polarizing film, the polarizing film can be bonded to other optical components. Furthermore, for example, when incorporating a polarizing film into a display device equipped with display elements such as liquid crystal cells and organic EL elements, the adhesive layer of the polarizing film can be bonded to the display elements.

[0111] Examples of adhesives used as materials for the adhesive layer include rubber-based adhesives, acrylic-based adhesives, polyvinyl ether-based adhesives, urethane-based adhesives, silicone-based adhesives, and polyolefin-based adhesives. Among these, acrylic-based adhesives and polyolefin-based adhesives are preferred from the viewpoint of heat resistance and productivity, and acrylic-based adhesives are particularly preferred. Furthermore, one type of adhesive may be used alone, or two or more types may be used in any ratio.

[0112] 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 greater than or equal to the lower limit of the above range, the adhesive strength of the adhesive layer can be increased, and the inclusion of air bubbles during bonding can be suppressed. Furthermore, when the thickness of the adhesive layer is less than or equal to the upper limit of the above range, the expansion and contraction behavior of the polarizing film can be suppressed, making bezel-free possible.

[0113] A laminate with an adhesive layer is typically 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.

[0114] [3. Polarizing film] Figure 3 is a schematic cross-sectional view showing a polarizing film according to an embodiment of the present invention. As shown in Figure 3, the polarizing film 300 comprises 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 optionally include an adhesive layer 305 between the polarizer layer 304 and the first resin layer 301.

[0115] According to the present invention, since the polarizing film has the first resin layer and the second resin layer described above, cracks in the polarizer layer are suppressed, and a polarizing film with good flatness of the second resin layer can be obtained.

[0116] [3.1. First resin layer and second resin layer] The first resin layer and the second resin layer may be the same as those described in the section [1. Laminate] above.

[0117] [3.2. Polarizer layer] As the polarizer layer, a film can be used that transmits one of two linearly polarized light whose vibration directions intersect at right angles, while absorbing or reflecting the other. Here, the vibration direction of linearly polarized light refers to the vibration direction of the electric field of the linearly polarized light. Such a film typically has a polarization transmission axis and can transmit linearly polarized light having a vibration direction parallel to the polarization transmission axis, while absorbing or reflecting linearly polarized light having a vibration direction perpendicular to the polarization transmission axis.

[0118] Specific examples of the polarizer layer include a polyvinyl alcohol resin film containing vinyl alcohol polymers such as polyvinyl alcohol and partially formalized polyvinyl alcohol, which is subjected to appropriate treatments such as dyeing with dichroic substances such as iodine and dichroic dyes, stretching, and crosslinking in an appropriate order and manner. The polarizer layer preferably contains polyvinyl alcohol resin.

[0119] The thickness of the polarizer layer is preferably greater than 1 μm, more preferably 2 μm or more, particularly preferably 3 μm or more, 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 greater than the lower limit of the above range, the optical performance of the polarizing film can be sufficiently improved. Also, when the thickness of the polarizer layer is less than or equal to the upper limit of the above range, the flexibility of the polarizing film can be effectively improved.

[0120] [3.3. Any layer] The polarizing film only needs to have at least a polarizer layer, a first resin layer, and a second resin layer, and any combination of layers may be used as needed.

[0121] [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 an adhesive layer, the first resin layer and the polarizer layer can be strongly bonded together.

[0122] The adhesive layer is formed 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, polyvinyl alkyl ether adhesives, rubber adhesives, vinyl chloride-vinyl acetate adhesives, SEBS (styrene-ethylene-butylene-styrene copolymer) adhesives, ethylene-styrene copolymers and other ethylene-based adhesives, and acrylic ester adhesives such as ethylene-(meth)acrylate copolymers and ethylene-(meth)acrylate copolymers. Furthermore, ultraviolet-curable adhesives are preferred because they allow for rapid curing.

[0123] The thickness of the adhesive layer is usually greater than 0 μm, preferably 0.1 μm or more, more preferably 1 μm or more, preferably 5 μm or less, and 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.

[0124] [3.3.2. Optical Anisotropy] A polarizing film may include an optically anisotropic layer as an optional layer. For example, a polarizing film for use in a liquid crystal display device may include an optical compensation film layer as an optically anisotropic layer to compensate for the viewing angle dependence of the liquid crystal contained in the liquid crystal cell and to compensate for the axial misalignment of the polarizer layer. Furthermore, for example, a polarizing film for use in a liquid crystal display device may include a λ / 4 layer as an optically anisotropic layer in combination with the optical compensation film layer to achieve a reflection suppression function. Organic EL displays do not usually require a polarizing film for RGB emission and image display, but by applying a polarizing film with a λ / 4 layer as an optically anisotropic layer, it is possible to improve the quality of black display characteristics.

[0125] The λ / 4 layer refers to 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, and particularly preferably 150 nm or less.

[0126] From the perspective of viewing angle characteristics, it is preferable that the three-dimensional refractive index of the λ / 4 layer exhibits uniaxiality such that nx > ny = nz. Furthermore, it is also preferable that the three-dimensional refractive index of the λ / 4 layer be nx > nz > ny, and ideally, it satisfies the relationship (nx - nz) / (nx - ny) = 0.5.

[0127] The slow axis of the λ / 4 layer is preferably at an angle of 45°±5° (i.e., 40°~50°), more preferably 45°±3° (i.e., 42°~48°), and particularly preferably 45°±1° (i.e., 44°~46°) with respect to the polarization transmission axis of the polarizer layer. This combination of the polarizer layer and the λ / 4 layer allows for the creation of a circular polarizer.

[0128] The λ / 4 layer preferably has inverse wavelength dispersion characteristics. The inverse wavelength dispersion characteristics refer to the property that the in-plane retardation Re(450) and Re(550) at measurement wavelengths of 450 nm and 550 nm satisfy Re(450) < Re(550). The λ / 4 layer having inverse wavelength dispersion characteristics can exhibit its optical function in a wide wavelength range.

[0129] The λ / 4 layer may be manufactured, for example, as a stretched film obtained by stretching a pre-stretched film formed of an appropriate resin. Also, the λ / 4 layer may be manufactured, for example, as a liquid crystal cured layer in which a layer of a liquid crystal composition containing an appropriate liquid crystalline compound is formed, the molecules of the liquid crystalline compound are aligned, and then the liquid crystal composition is cured. Among them, from the viewpoint of obtaining a thin and flexible polarizing film, the λ / 4 layer is preferably a liquid crystal cured layer. The 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.

[0130] The polarizing film may further include a λ / 2 layer as an optional layer. The λ / 2 layer refers to 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.

[0131] From the viewpoint of the 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 may preferably be nx > nz > ny, and it is ideal to satisfy the relationship of (nx - nz) / (nx - ny) = 0.5.

[0132] The slow axis of the λ / 2 layer may be set arbitrarily according to the optical function that the polarizing film is to exhibit. For example, when a polarizing film is provided with a combination of a λ / 2 layer and a λ / 4 layer, if the angle θ(λ / 4) made by the slow axis of the λ / 4 layer with respect to a certain reference direction and the angle θ(λ / 2) made by the λ / 2 layer with respect to the same reference direction satisfy equation (X): "θ(λ / 4) = 2θ(λ / 2) + 45°", then the combination of the λ / 2 and λ / 4 layers can function as a broadband λ / 4 plate that can impart in-plane retardation of approximately 1 / 4 wavelength of the wavelength of light passing through the λ / 2 and λ / 4 layers in a wide wavelength range (see Japanese Patent Publication No. 2007-004120). Therefore, when trying to obtain a polarizing film that can function as a circular polarizer in a wide wavelength range, it is preferable to set the slow axes of the λ / 2 and λ / 4 layers so as to satisfy a relationship close to the above equation (X). For example, the slow axes of the λ / 2 layer and the λ / 4 layer preferably satisfy one of the following relationships (X1) to (X3).

[0133] (X1) The angle between the slow axis of one of the λ / 4 layer and the λ / 2 layer and the polarization transmission axis of the polarizer layer is preferably 75°±5° (i.e., 70°~80°), more preferably 75°±3° (i.e., 72°~78°), and particularly preferably 75°±1° (i.e., 74°~76°), and the angle between the slow axis of the other of the λ / 4 layer and the λ / 2 layer and the polarization transmission axis of the polarizer layer is preferably 15°±5° (i.e., 10°~20°), more preferably 15°±3° (i.e., 12°~18°), and particularly preferably 15°±1° (i.e., 14°~16°).

[0134] (X2) The angle between the slow axis of one of the λ / 4 layer and the λ / 2 layer and the polarization transmission axis of the polarizer layer is preferably 15°±5° (i.e., 10°~20°), more preferably 15°±3° (i.e., 12°~18°), and particularly preferably 15°±1° (i.e., 14°~16°), and the angle between the slow axis of the other of the λ / 4 layer and the λ / 2 layer and the polarization transmission axis of the polarizer layer is preferably 75°±5° (i.e., 70°~80°), more preferably 75°±3° (i.e., 72°~78°), and particularly preferably 75°±1° (i.e., 74°~76°).

[0135] (X3) The angle between the slow axis of one of the λ / 4 layer and the λ / 2 layer and the polarization transmission axis of the polarizer layer is preferably 22.5°±5° (i.e., 17.5°~27.5°), more preferably 22.5°±3° (i.e., 19.5°~25.5°), and particularly preferably 22.5°±1° (i.e., 21.5°~23.5°), and the angle between the slow axis of the other of the λ / 4 layer and the λ / 2 layer and the polarization transmission axis of the polarizer layer is preferably 90°±5° (i.e., 85°~95°), more preferably 90°±3° (i.e., 87°~93°), and particularly preferably 90°±1° (i.e., 89°~91°).

[0136] Here, the direction in which one of the λ / 4 layer and the λ / 2 layer forms the aforementioned angle with respect to the polarization transmission axis of the polarizer layer is usually the same as the direction in which the other of the λ / 4 layer and the λ / 2 layer forms the aforementioned angle with respect to the polarization transmission axis of the polarizer layer.

[0137] The λ / 2 layer preferably has inverse wavelength dispersion characteristics. A λ / 2 layer having inverse wavelength dispersion characteristics can exhibit its optical function over a wide wavelength range.

[0138] The λ / 2 layer may be manufactured, for example, as a stretched film. Alternatively, the λ / 2 layer may be manufactured, for example, as a liquid crystal curing layer. In particular, from the viewpoint of obtaining a thin and flexible polarizing film, the λ / 2 layer is preferably a liquid crystal curing layer. Such a λ / 2 layer as a liquid crystal curing layer can be manufactured, for example, by the method described in International Publication No. 2016 / 121602.

[0139] The polarizing film may further include a positive C plate layer as an optional layer. In particular, if the polarizing film does not have a λ / 4 layer or λ / 2 layer having a three-dimensional refractive index that satisfies the relationship (nx-nz) / (nx-ny)=0.5, it is preferable that the polarizing film includes a positive C plate layer. 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 λ / 2 layer having a three-dimensional refractive index that satisfies the relationship (nx-nz) / (nx-ny)=0.5, the presence of a positive C plate layer allows for appropriate adjustment of the refractive index in the thickness direction, thereby improving the viewing angle characteristics. Furthermore, multiple positive C plate layers may be used in combination with the optical anisotropic layers such as the λ / 2 layer and λ / 4 layer described above.

[0140] The positive C plate layer may be manufactured, for example, as a stretched film. Alternatively, the positive C plate layer may be manufactured, for example, as a liquid crystal cured layer. In particular, 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 manufactured, for example, by the method described in Japanese Patent Application Publication No. 2015-14712, Japanese Patent Application Publication No. 2015-57646, etc. Furthermore, a liquid crystalline compound having inverse wavelength dispersion characteristics may be used as the liquid crystalline compound for manufacturing the positive C plate layer.

[0141] The aforementioned layers may be of a single type or a combination of two or more types. Furthermore, the number of layers may be one or two or more. In addition, the positions of the aforementioned layers are arbitrary, as long as they do not significantly impair the effects of the present invention.

[0142] [3.3.3. Any other layer] Further examples of arbitrary layers that a polarizing film may have include a clear hard coat layer, an anti-glare hard coat layer, an anti-reflective layer, an anti-static layer, and an anti-fouling layer. Any of the above-mentioned layers may be used individually or in combination of two or more. Furthermore, the number of arbitrary layers may be one or two or more. Moreover, the position of any arbitrary layer is not limited as long as it does not significantly impair the effects of the present invention.

[0143] [3.4. Thickness and applications of polarizing film] According to the present invention, even if the protective layer composed of the laminated portion of the first resin layer and the second resin layer is thin, the polarizer layer can be effectively protected, so it is usually possible to make the entire polarizing film thin. The thickness of the polarizing film is preferably 40 μm or more, more preferably 50 μm or more, particularly preferably 60 μm or more, preferably 110 μm or less, more preferably 90 μm or less, and particularly preferably 70 μm or less.

[0144] Polarizing films can typically be used in combination with display elements of display devices. Examples of display elements include liquid crystal panels used as display elements for liquid crystal display devices and organic electroluminescent panels used as display elements for organic electroluminescent display devices. Typically, polarizing films are provided on the viewing side of these display elements.

[0145] [4. Polarizing film with adhesive layer] Figure 4 is a schematic cross-sectional view showing an adhesive polarizing film according to one embodiment of the present invention. As shown in Figure 4, the adhesive polarizing film 400 comprises 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 adhesive polarizing film 400 optionally has an adhesive layer 405 between the polarizer layer 404 and the first resin layer 401. The adhesive laminated film 400 shown in Figure 4 can be considered as having the first resin layer 401, the second resin layer 402, and the adhesive layer 403 as the aforementioned adhesive laminate, and a polarizer layer provided on the first resin layer of the adhesive laminate.

[0146] The laminate with adhesive layer and the polarizer layer can be the same as those described in the sections [2. Laminate with adhesive layer] and [3. Polarizing film], [3.2. Polarizer layer] above.

[0147] [5. Method for manufacturing polarizing film] The method for manufacturing a polarizing film according to the present invention is not limited as long as the above-described polarizing film can be obtained. For example, a polarizing film may be manufactured by a method for manufacturing a polarizing film that includes, in this order: (A) a step of applying a second resin liquid containing a second resin onto a peelable substrate film and drying it to form a second resin layer; (B) a step of applying a first resin liquid containing a first resin onto the second resin layer and drying it to form a first resin layer; (C) a step of laminating a polarizer layer and a first resin layer; and (D) a step of peeling the substrate film from the second resin layer.

[0148] [5.1. Process (A): Formation of the second resin layer] In step (A), a second resin liquid containing the second resin is applied to a peelable substrate 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 the components that can be contained in the second resin. Specifically, the second resin liquid contains a polymer and may optionally contain any components that the second resin contains, an ultraviolet absorber, and a solvent. Some or all of the polymer, any components, and nonvolatile components such as the ultraviolet absorber may be dissolved in the solvent. Also, some or all of the nonvolatile components may be dispersed in the solvent.

[0149] As the solvent, an organic solvent is preferred, and an organic solvent capable of dissolving the polymer contained in the second resin is particularly preferred. Examples of solvents include hydrocarbon solvents such as cyclohexane and toluene; cyclic ether solvents such as tetrahydrofuran; and so on. One type of solvent may be used alone, or two or more types may be used in any ratio.

[0150] The concentration of the non-volatile component in the second resin liquid can be arbitrarily set within a range that gives the second resin liquid a viscosity suitable for application. The 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.

[0151] The shape of the peelable base film is not limited, but a long film is preferred.

[0152] Methods for applying the second resin liquid to the base film include, for example, curtain coating, extrusion coating, roll coating, spin coating, dip coating, bar coating, spray coating, slide coating, printing coating, gravure coating, die coating, gap coating, and dipping.

[0153] By applying a second resin solution to a peelable substrate film, a layer of the second resin solution is formed on the peelable substrate film. By drying the second resin solution after application, volatile components such as solvents are removed from the second resin solution layer, resulting in a second resin layer containing the second resin.

[0154] The specific drying temperature may vary depending on the type and amount of polymer, reverse plasticizer, and solvent, but generally, it is preferably 90°C or higher, more preferably 100°C or higher, particularly preferably 110°C or higher, preferably 140°C or lower, more preferably 135°C or lower, and particularly preferably 130°C or lower.

[0155] The specific drying time may vary depending on the type and amount of polymer, reverse plasticizer, and solvent, but generally it is preferably 30 seconds or more, more preferably 60 seconds or more, particularly preferably 90 seconds or more, preferably 5 minutes or less, more preferably 4 minutes or less, and particularly preferably 3 minutes or less.

[0156] [5.2. Process (B): Formation of the first resin layer] In step (B), a first resin liquid containing the first resin is applied to 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 the components that can be contained in the first resin. Specifically, the first resin liquid may contain a polymer, a solvent, and optionally any components contained in the second resin and an ultraviolet absorber. Some or all of the non-volatile components such as the polymer, optional components and ultraviolet absorber may be dissolved in the solvent. Also, some or all of the non-volatile components may be dispersed in the solvent.

[0157] The solvent used in the first resin solution and its content, as well as the application method and drying method of the first resin solution, may be the same as those described in the section [5.1. Step (A): Formation of the second resin layer] above.

[0158] [5.3. Process (C): Lamination of the first resin layer and polarizer layer] In step (C), the polarizer layer and the first resin layer are bonded together. The bonding of the first resin layer and the polarizer layer may be done 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 together using a bonding tool such as a pinch roller, with an adhesive, if necessary.

[0159] [5.4. Process (D): Peeling off the base film] In step (D), the base film is peeled off. Typically, the base film is peeled off continuously. In this case, it is preferable to set the peeling speed appropriately within a range that can suppress the rupture of the first resin layer and the second resin layer. 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, and particularly preferably 50 m / min or less.

[0160] [5.5. Other processes] The method for manufacturing the polarizing film described above may include any additional steps as needed. Examples of these optional steps include the step of arranging the optically anisotropic layer described above and the step of forming an adhesive layer. [Examples]

[0161] The present invention will be specifically described below with reference to examples. However, the present invention is not limited to the examples shown below, and can be modified and implemented as appropriate without departing from the scope of the claims and equivalents of the present invention.

[0162] In the following explanation, "%" and "parts" refer to weight unless otherwise specified. Furthermore, the operations described below were performed in ambient air at normal temperature and pressure unless otherwise specified.

[0163] In the following explanation, styrene-derived repeating units will be abbreviated as "St," and polymer blocks formed from styrene-derived repeating units will be referred to as "St blocks." In the following explanation, isoprene-derived repeating units will be abbreviated as "IP," and polymer blocks formed from isoprene-derived repeating units will be referred to as "IP blocks." In the following explanation, random polymerization blocks formed from styrene-derived repeating units and isoprene-derived repeating units may be referred to as "St-IP blocks."

[0164] [Evaluation Method] [Method for measuring the weight-average molecular weight Mw and number-average molecular weight Mn of polymers] The weight-average molecular weight (Mw) and number-average molecular weight (Mn) of the polymers were measured using a gel permeation chromatography (GPC) system (HLC8020GPC, manufactured by Tosoh Corporation) as polystyrene-based or polyisoprene-based values. When polystyrene was used as the standard substance, tetrahydrofuran was used as the solvent. When polyisoprene was used as the standard substance, cyclohexane was used as the solvent. The measurement temperature was 38°C.

[0165] [Method for measuring the hydrogenation rate of polymers] The hydrogenation rate of polymers is 1 The measurement was performed using 1H-NMR.

[0166] [Method for measuring thickness] The film thickness was measured using a snap gauge.

[0167] [Method for measuring the storage modulus] A 1mm thick measurement film was prepared by thermal melting and molding the target resin using a thermal melting press under the conditions of a 1mm clearance, a temperature of 250°C, and a pressure of 30MPa. The storage modulus was then measured. The storage modulus was measured using a dynamic viscoelasticity measuring device (ARES, manufactured by T.A. Instruments Japan) under the conditions of 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 was read.

[0168] [Method for measuring water vapor transmission rate] A 100 μm thick measurement film was prepared by thermal melting and molding the target resin using a thermal melting press under the conditions of a clearance of 100 μm, a temperature of 250°C, and a pressure of 30 MPa. The water vapor transmission rate was then measured. The water vapor transmission rate was measured using a water vapor transmission rate measuring device ("PERMATRAN-W" manufactured by MOCON Corporation) according to JIS K 7129 B method, under the conditions of a temperature of 40°C and a humidity of 90% RH.

[0169] [Method for measuring the photoelastic constant] The first and second resin solutions (resin solutions) used in the examples and comparative examples, as well as a PET film (polyethylene terephthalate film; Mitsubishi Chemical Corporation's "MRV38") with a silicone release treatment applied to its surface, were prepared. The resin solutions were applied to this PET film using a die coater. Subsequently, the solvent components were evaporated by drying at 100°C for 2 minutes to obtain a resin layer with a thickness of 10 μm. The resin layer was peeled from the PET film and used as a resin layer for measurement. Resin layers for measurement using each of the first resin solutions and each of the second resin solutions used in the examples and comparative examples were prepared, and the photoelastic constants were measured.

[0170] Multiple 1cm wide film pieces were prepared by cutting out a film-like resin layer for measurement. Weights of 50g, 100g, 150g, and 200g were suspended from these film pieces, and in-plane retardation was measured at a wavelength of 550nm. In-plane retardation was measured using a phase difference meter (AXOMETRICS "Axo Scan"). The measured in-plane retardation was divided by the thickness of the resin layer to obtain the birefringence. The obtained birefringence and the magnitude of the force per unit cross-sectional area applied to the resin layer by the weight corresponding to that birefringence were plotted on a coordinate system with the magnitude of the force on the horizontal axis and birefringence on the vertical axis. An approximate straight line was obtained from the obtained plot using the least squares method. The photoelastic constant of the measurement resin layer was determined as the slope of this approximate straight line.

[0171] [Method for measuring retardation] Using a method similar to that used for forming the measurement resin layer in the photoelastic constant measurement method, a resin layer with a thickness corresponding to the first resin layer and a resin layer with a thickness corresponding to the second resin layer (2 μm to 5 μm) were obtained as measurement resin layers. For the obtained measurement resin layers, the in-plane retardation Re and the retardation Rth in the thickness direction were measured at a measurement wavelength of 550 nm using a phase difference meter (AXOMETRICS "Axo Scan").

[0172] [Method for measuring transmittance at 380nm] A measurement resin layer similar to that used for retardation measurement was prepared. A glass substrate (Corning Eagle XG; 0.5 mm thick) was prepared. The measurement resin layer was bonded to this glass substrate via an optical adhesive sheet (Nitto Denko LUCIACS CS9861US), obtaining a sample with a layer configuration of glass substrate / optical adhesive sheet / measurement resin layer. Since neither the glass substrate nor the optical adhesive sheet absorbs light at a wavelength of 380 nm, the light transmittance of the sample matches that of the measurement resin layer. Therefore, the light transmittance at a wavelength of 380 nm was measured using a spectrophotometer (JASCO V-7200).

[0173] [Method for evaluating the ease of surface irregularities of the second resin layer in a laminate] The substrate film was peeled off from a laminate consisting of a first resin layer, a second resin layer, and a substrate film, exposing the second resin layer. The light release liner of an optical adhesive sheet (Nitto Denko "LUCIACS CS9861US") was peeled off, and a laminated sample was prepared by passing it through a pinch roll. The heavy release liner was then peeled off, and the sample was bonded to glass and inspected for appearance. The following evaluation criteria were used for evaluation. S: No defects were found at all due to the uneven structure of the base film. It is in excellent condition for use. A: No defects were observed that were caused by the uneven structure of the substrate film, with dimensions of 15 μm square or larger. It is in very good condition for use. B: Although usable, defects were found in the substrate film that were larger than 15 μm square but less than 20 μm square, due to the uneven structure of the substrate film.

[0174] [Transferability to polarizing film] An adhesive was applied to the first resin layer of a laminate consisting of a first resin layer, a second resin layer, and a base film. After bonding and drying with the polarizer layer, the base film was continuously peeled off from the second resin layer of the laminate, exposing the second resin layer. The peelability of the base film (transferability to the polarizing film) was evaluated using the following evaluation index. A: The base film could be continuously peeled off from the second resin layer. B: The peeling force was excessively strong, making it difficult to peel from the second resin layer, or the peeling force was too weak, resulting in peeling at an unintended time.

[0175] [Web handling properties of laminates] The following aspects of the web handling properties of the laminate were evaluated. In the process of applying the second resin layer to the base film when manufacturing a laminate with a layer structure of first resin layer / second resin layer / base film, the presence or absence of delamination between the second resin layer and the base film, and the presence or absence of curling at the edges of the resulting laminate were evaluated. In addition, the presence or absence of blocking when the laminate was wound into a roll and unwound from the roll was evaluated. If blocking occurs, stable manufacturing of the laminate and polarizing film is usually difficult. Furthermore, if delamination is observed between the second resin layer and the base film, stable manufacturing of the laminate with the aforementioned layer structure is usually difficult, regardless of the presence or absence of curling and blocking at the edges. S: No delamination, edge curling, or blocking occurred between the second resin layer and the base film. A: No delamination or blocking occurred between the second resin layer and the base film. Slight curling was observed at the edges. B: No delamination occurred between the second resin layer and the base film. Curling was observed at the edges. Blocking between the second resin layer and the back surface of the base film was occasionally observed. C: Delamination was observed between the second resin layer and the base film.

[0176] [Method for evaluating the humidification reliability of polarizing films] A 5cm square evaluation sample was obtained by laminating a polarizing film onto a glass plate. This evaluation sample was subjected to a humidification test, where it was left standing for 500 hours in an environment of 60°C and 95% RH. After the test, the iodine loss at the edges of the polarizing film in the evaluation sample was evaluated. Judgment criteria A: No iodine loss occurs at the edges. B: The portion of the material at the end where iodine loss occurred was less than 0.1 mm. C: The portion at the end where iodine loss occurred was 0.1 mm or larger.

[0177] [Method for evaluating cracks in the polarizer layer of polarizing films] A polarizing film was bonded to a glass plate to obtain a 5cm square evaluation sample. Twenty cycles of cold and heat cycling tests were performed at -40°C for 30 minutes and 85°C for 30 minutes. The length of cracks in the polarizer layer was measured by microscopic observation. In cases where multiple cracks occurred, the evaluation was based on their average length. A: Less than 0.1 mm B: 0.1mm or more and less than 0.15mm C: 0.2mm or more

[0178] [Manufacturing Example 1: Preparation of Resin X1] As resin X1 to be used in the first resin, a norbornene-based polymer (ZEONOR, manufactured by Zeon Corporation, with a glass transition temperature Tg: 133°C) resin pellet was prepared.

[0179] [Manufacturing Example 2: Preparation of Resin X2] As resin X2 to be used as the first resin, a norbornene-based polymer (ZEONOR, manufactured by Zeon Corporation, with a glass transition temperature Tg: 163°C) resin pellet was prepared.

[0180] [Manufacturing Example 3: Preparation of Resin Y1] (1. Synthesis of block copolymers) The resin Y1 used for the second resin was manufactured using the following procedure. After thoroughly drying the stainless steel reactor equipped with a stirring device, it was purged with nitrogen. 320 parts of dehydrated cyclohexane, 25.0 parts of styrene monomer, and 0.38 parts of dibutyl ether were charged into this reactor to obtain a reaction solution. While stirring this reaction solution at 60°C, 0.36 parts of n-butyllithium solution (15% hexane solution) were added to initiate the first stage of polymerization. After carrying out 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 of polymerization was carried out for another hour. Subsequently, 25.0 parts of styrene monomer were added to the reaction solution, and the third stage of polymerization was carried out for another hour. Subsequently, 0.2 parts of isopropyl alcohol were added to the reaction solution to stop the reaction. This yielded a block copolymer in the reaction solution having the structure of styrene block / styrene-isoprene random copolymer block / styrene block.

[0181] (2. Hydrogenation of block copolymers) Next, the reaction solution was transferred to a pressure reactor equipped with a stirring device. Ten parts of a silica-alumina-supported nickel catalyst (JGC Chemical Industries, Ltd. "E22U", nickel load 60%) was added to the pressure reactor as a hydrogenation catalyst and mixed. The inside of the reactor was also purged with hydrogen gas. After that, hydrogen was supplied to the reactor while stirring the reaction solution, and the hydrogenation reaction was carried out at a temperature of 160°C and a pressure of 4.5 MPa for 8 hours. After the hydrogenation reaction was complete, the reaction solution was filtered to remove the hydrogenation catalyst. Then, 800 parts of cyclohexane were added to the reaction solution to dilute it. 3500 parts of isopropanol were poured into the diluted reaction solution to precipitate the hydride of the block copolymer. The isopropanol used was filtered through a 1 μm pore size filter in a Class 1000 cleanroom. The precipitated block copolymer hydride was separated and recovered by filtration, and then dried under reduced pressure at 80°C for 48 hours.

[0182] The resulting block copolymer hydride was a ternary block copolymer hydride consisting of an St block, an St-IP block, and an St block, with a molar ratio of 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 approximately 100% for the main chain and aromatic rings.

[0183] (3. Preparation of resin Y1) To 100 parts of the hydride of the aforementioned block copolymer, 0.1 parts of pentaerythrityl tetrakis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate] ("Songnox1010" manufactured by Matsubara Sangyo Co., Ltd.) was melt-kneaded as an antioxidant to obtain resin Y1. This resin Y1 was molded into pellets and recovered.

[0184] [Manufacturing Example 4: Preparation of Resin Y2] The resin Y2, to be used as the second resin, was manufactured using the following procedure. Resin Y2 was obtained by melt-kneading 100 parts of resin Y1 produced in Production Example 1 with 30 parts of polyisobutene (JX Nippon Oil & Energy Corporation's "Nisseki Polybutene HV-300", number average molecular weight 1,400) as a softening agent.

[0185] [Manufacturing Example 5: Manufacturing and Evaluation of Resin Y3] The resin Y3, to be used as the second resin, was manufactured using the following procedure. Resin Y3 was synthesized using the same procedure as in Production Example 1, except that in the second step of the polymerization reaction for the production of resin Y1, 50 parts of isoprene monomer were added instead of 25.0 parts of styrene monomer and 25.0 parts of isoprene monomer.

[0186] The hydride of the block copolymer contained in resin Y3 is a hydride of a ternary block copolymer consisting of St blocks, IP blocks, and St blocks, with a molar ratio of 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 approximately 100% for the main chain and aromatic rings.

[0187] [Example 1] (1. Fabrication of the laminate) Resin X1 was dissolved in a mixed solvent of cyclohexane and ethylcyclohexane at a solid content of 15%, and the ultraviolet absorber (2-(2H-benzotriazol-2-yl)-4-(1,1,3,3-tetramethylbutyl)phenol; BASF's "Tinuvin® 329" was added. The mixture was then stirred again to prepare the first resin solution, which was completely dissolved. Resin Y1 was dissolved in a mixed solvent of cyclohexane and ethylcyclohexane at a solid content of 15%, and the ultraviolet absorber (2-(2H-benzotriazol-2-yl)-4-(1,1,3,3-tetramethylbutyl)phenol; BASF's "Tinuvin® 329" was added. The mixture was then stirred again to prepare a second resin solution in which the resin was completely dissolved. A PET film (polyethylene terephthalate film; Mitsubishi Chemical's "MRV38", tensile modulus of elasticity 4000 MPa) with a silicone release treatment applied to its surface was prepared. A second resin solution was applied to this PET film using a die coater. After drying at 100°C for 2 minutes, a first resin solution was applied and dried at 100°C for 2 minutes to evaporate the solvent components, forming a laminate on the base film consisting of a 2 μm thick second resin layer and a 5 μm thick first resin layer.

[0188] (2. Manufacturing of the polarizer layer) As a long roll of raw film, an unstretched polyvinyl alcohol film (vinylon film, average degree of polymerization approximately 2400, degree of saponification 99.9 mol%) with a thickness of 20 μm was prepared. While this film was continuously conveyed in the longitudinal direction via guide rolls, the film was subjected to a swelling treatment by immersion in pure water at 30°C for 1 minute, and a dyeing treatment by immersion in a dyeing solution (dyeing solution containing iodine and potassium iodide in a molar ratio of 1:23, dyeing concentration 1.2 mmol / L) at 32°C for 2 minutes to adsorb iodine onto the film. After that, the film was washed with a 3% boric acid aqueous solution at 35°C for 30 seconds. Subsequently, the film was stretched 6.0 times at 57°C in an aqueous solution containing 3% boric acid and 5% potassium iodide. After that, the film was subjected to a complementary color treatment at 35°C in an aqueous solution containing 5% potassium iodide and 1.0% boric acid. The film was then dried at 60°C for 2 minutes to obtain a polarizer layer with a thickness of 7 μm. The polarization degree of this polarizer layer was measured using a UV-Vis spectrophotometer (JASCO Corporation "V-7200") and was found to be 99.996%.

[0189] (3. Preparation of polarizing film) A TAC film (Konica Minolta "KC4UY", 40 μm thick, saponified) was prepared and inline coated with a water-based adhesive (Mitsubishi Chemical's Gosenex Z-200 3 wt% aqueous solution). After inline corona treatment of the first resin layer of the laminate, a water-based adhesive (Mitsubishi Chemical's Gosenex Z-200 3 wt% aqueous solution) was inline coated. A polarizer layer was laminated between the water-based adhesive coated surface of the TAC film and the water-based adhesive coated surface of the first resin layer of the laminate, and immediately after being bonded by passing it between nip rolls, it was dried at 85°C for 5 minutes to obtain a polarizing film with a base film in which the TAC film, polarizer layer, first resin layer, second resin layer, and base film were laminated in this order.

[0190] (4. Formation of the adhesive layer) The base film was peeled off from the polarizing film with the base film attached, and the second resin layer was subjected to inline corona treatment. Then, the light release liner of the optical adhesive sheet (Nitto Denko "LUCIACS CS9861US": 25 μm thick) was peeled off to expose one side of the optical adhesive sheet, and it was bonded to the above laminate by passing it through a nip roll. The aforementioned evaluation was performed on the resulting laminate.

[0191] [Example 2] In Example 1 (1. Preparation of Laminate), except that no UV absorber was added to the first resin solution, resin Y2 was used as the resin in the second resin solution without adding a UV absorber, and the thickness of the first resin layer was set to 2 μm, a laminate, a polarizing film, and a polarizing film with an adhesive layer were prepared in the same manner as in Example 1, and the aforementioned evaluations were performed on the obtained laminate and polarizing film.

[0192] [Examples 3-6] In Example 1 (1. Preparation of Laminate), the laminate, polarizing film, and polarizing film with adhesive layer were prepared in the same manner as in Example 1, except that the type of resin and presence or absence of UV absorber in the first resin liquid, the type of resin and presence or absence of UV absorber in the second resin liquid, and the respective thicknesses of the first and second resin layers were as shown in Table 1. The obtained laminate and polarizing film were then evaluated as described above.

[0193] [Example 7] Laminates, polarizing films, and polarizing films with adhesive layers were prepared in the same manner as in Example 3, except that an untreated OPP film (biaxially oriented polyolefin film; Toray Industries' "New Type Trefan BO 40-2500", tensile modulus 2000 MPa) was used as the peelable base film. The obtained laminates and polarizing films were then evaluated as described above.

[0194] [Comparative Example 1] In Example 1 (1. Preparation of Laminate), the laminate, polarizing film, and polarizing film with adhesive layer were prepared in the same manner as in Example 1, except that the first resin contained in the first resin liquid was resin X1 and no ultraviolet absorber was added, the thickness of the first resin layer was set to 4 μm, and a second resin layer was not formed. The obtained laminate and polarizing film were then evaluated as described above.

[0195] [Comparative Example 2] Except for using an untreated OPP film (biaxially oriented polyolefin film; Toray Industries' "New Type Trefan BO 40-2500", tensile modulus 2000 MPa) as the peelable base film, laminates, polarizing films, and polarizing films with adhesive layers were prepared in the same manner as in Comparative Example 1, and the aforementioned evaluations were performed on the obtained laminates and polarizing films.

[0196] [Comparative Example 3] Except for the fact that in Example 1 (1. Preparation of Laminate), the first resin layer was not formed, the second resin contained in the second resin liquid was resin Y2 and no ultraviolet absorber was added, and the thickness of the second resin layer was set to 4 μm, a laminate, a polarizing film, and a polarizing film with an adhesive layer were prepared in the same manner as in Example 1, and the aforementioned evaluation was performed on the obtained laminate and polarizing film.

[0197] [Comparative Example 4] Except for using an untreated OPP film (biaxially oriented polyolefin film; Toray Industries' "New Type Trefan BO 40-2500", tensile modulus 2000 MPa) as the peelable base film, laminates, polarizing films, and polarizing films with an adhesive layer were prepared in the same manner as in Comparative Example 3, and the aforementioned evaluations were performed on the obtained laminates and polarizing films.

[0198] The results are shown in Tables 1 and 2. In the tables below, the meanings of the abbreviations are as follows: UVA: UV absorber Re: In-plane lettering Rth: Retarding in the thickness direction "Si-PET": PET film (polyethylene terephthalate film; Mitsubishi Chemical Corporation's "MRV38") with a silicone-based release treatment applied to the surface. "OPP": Untreated OPP film (biaxially oriented polyolefin film; Toray's "New Type Trefan BO 40-2500").

[0199] [Table 1]

[0200] [Table 2]

[0201] As shown in Examples 1 to 7, in laminates 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 surface irregularities on the second resin layer could be mitigated while suppressing the occurrence of polarizer cracks when used as a polarizing film. On the other hand, as shown in Comparative Examples 1 and 2, in laminates having only a first resin layer with a predetermined storage modulus, it was difficult to mitigate surface irregularities on the second resin layer. Furthermore, in Comparative Example 1, it was confirmed that the web handling properties and transferability were reduced due to insufficient adhesion between the base film and the resin layer.

[0202] Furthermore, as shown in Comparative Examples 3 and 4, it was confirmed that it is difficult to suppress polarizer cracks in laminates having only a second resin layer with a predetermined storage modulus. In addition, it was confirmed that sufficient humidification reliability could not be obtained in Comparative Examples 3 and 4. This is presumed to be due to poor adhesion between the polarizer layer and the second resin layer during bonding of the second resin layer and the polarizer layer. In particular, in Comparative Example 4, the smoothness of the surface of the second resin layer was lost due to blocking between the second resin layer and the back surface of the substrate, so it is presumed that the poor adhesion between the polarizer layer and the second resin layer had a significant impact. [Explanation of Symbols]

[0203] 100-layer structure 101, 201, 301 and 401 First resin layer 102, 202, 302 and 402 Second resin layer 20 Peelable base film 200 Laminates with adhesive layer 203, 403 adhesive layer 300 Polarizing Film 304 and 404 polarizer layers 305 and 405 adhesive layers

Claims

1. The device comprises a first resin layer, a second resin layer, and a peelable base film in this order. The first resin layer comprises a first resin having a storage modulus of 650 MPa or more and 1700 MPa or less, as measured as a film with a thickness of 1 mm. The second resin layer comprises a second resin having a storage modulus of 10 MPa or more and less than 650 MPa, as measured as a film with a thickness of 1 mm. The first resin layer is provided directly on the second resin layer, The first resin layer is formed from the first resin, or from the first resin and an ultraviolet absorber, wherein the content of the ultraviolet absorber in the first resin layer is 40% by weight or less. The laminate is formed from the second resin or from the second resin and an ultraviolet absorber, wherein the content of the ultraviolet absorber in the second resin layer is 40% by weight or less.

2. The laminate according to claim 1, wherein the thickness of the first resin layer is greater than 0 μm and 12 μm or less, and the thickness of the second resin layer is greater than 0 μm and 12 μm or less.

3. The laminate according to claim 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, when measured independently as a 100 μm thick film, have a water vapor transmission rate of 4 g / (m²) at 40°C and 90% RH. ２ - The laminate according to any one of claims 1 to 3, wherein the number of days is less than or equal to the number of days.

5. The laminate according to any one of claims 1 to 4, wherein the first resin layer and the second resin layer each independently have an in-plane retardation of 5 nm or less and an absolute value of the retardation in the thickness direction of 5 nm or less.

6. The first resin layer and the second resin layer each independently have a photoelastic constant of 5 × 10 －１３ cm ２ A laminate according to any one of claims 1 to 5, wherein the value is less than or equal to / dyn.

7. 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.

8. The second resin is a block copolymer hydride [E] in which the polymer having the alicyclic structure is 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 whose main component is repeating units [I] derived from aromatic vinyl compounds. Polymer block [B] is a polymer block mainly composed of repeating units [I] derived from aromatic vinyl compounds and repeating units [II] derived from chain-like conjugated diene compounds. The laminate according to claim 7, wherein the polymer block [C] is a polymer block mainly composed of repeating units [II] derived from a chain-like conjugated diene compound.

9. The laminate according to 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.

10. The laminate according to any one of claims 1 to 9, wherein the second resin comprises a plasticizer and / or a softening agent.

11. The laminate according to claim 10, wherein the plasticizer and / or softener is one or more selected from the group consisting of ester-based plasticizers and aliphatic hydrocarbon polymers.

12. 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.

13. The laminate according to any one of claims 1 to 12, wherein the tensile modulus of the peelable base film is 2000 MPa or more.

14. The first resin layer, the second resin layer, and the adhesive layer are provided in this order. The first resin layer comprises a first resin having a storage modulus of 650 MPa or more and 1700 MPa or less, as measured as a film with a thickness of 1 mm. The second resin layer comprises a second resin having a storage modulus of 10 MPa or more and less than 650 MPa, as measured as a film with a thickness of 1 mm. The first resin layer is provided directly on the second resin layer, The first resin layer is formed from the first resin, or from the first resin and an ultraviolet absorber, wherein the content of the ultraviolet absorber in the first resin layer is 40% by weight or less. The second resin layer is formed from the second resin, or from the second resin and an ultraviolet absorber, wherein the content of the ultraviolet absorber in the second resin layer is 40% by weight or less. A laminate with an adhesive layer, wherein the thickness of the adhesive layer is 2 μm or more and 25 μm or less.

15. The polarizer layer, the first resin layer, and the second resin layer are provided in this order. The first resin layer comprises a first resin having a storage modulus of 650 MPa or more and 1700 MPa or less, as measured as a film with a thickness of 1 mm. The second resin layer contains a second resin whose storage modulus, measured as a 1 mm thick film, is 10 MPa or more and less than 650 MPa. The first resin layer is provided directly on the second resin layer, The first resin layer is formed from the first resin, or from the first resin and an ultraviolet absorber, wherein the content of the ultraviolet absorber in the first resin layer is 40% by weight or less. A polarizing film in which the second resin layer is formed from the second resin or from the second resin and an ultraviolet absorber, wherein the content of the ultraviolet absorber in the second resin layer is 40% by weight or less.

16. The polarizing film according to claim 15, wherein the thickness of the polarizer layer is greater than 1 μm and 12 μm or less.

17. A polarizing film with an adhesive layer, comprising an adhesive laminate as described in claim 14, and a polarizer layer provided on the first resin layer of the adhesive laminate.

18. A method for manufacturing a polarizing film according to claim 15 or 16, A step of forming a second resin layer by applying a second resin liquid containing the second resin onto a peelable substrate film and drying it, The process of applying a first resin liquid containing the first resin onto the second resin layer and drying it to form a first resin layer, A step of bonding the polarizer layer and the first resin layer, A method for manufacturing a polarizing film, comprising the steps of peeling the peelable base film from the second resin layer in this order.

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