Optical laminate and elliptical polarizing plate including the same

Abstract

To provide an optical laminate which hardly causes distortion when bent, has high flexibility and an excellent oblique reflection rate, and is suitable for a flexible display.SOLUTION: An optical laminate includes a retardation film 1, a polarizer 3 and a transparent protective film 5 in this order, in which the retardation film 1 includes a base material film 11 having moisture vapor permeability of 100 g / m2 / 24 hours or more, and a liquid crystal cured film 13 that is formed on the base material film 11, has a thickness of 0.5 μm or more and 3 μm or less and satisfies the following expressions (1) and (2): Re(450) / Re(550)≤1.00(1) and 1.00≤Re(650) / Re(550)(2) as a single layer, the polarizer 3 is composed of a polyvinyl alcohol-based resin film containing a dichroic dye, the transparent protective film 5 has total light transmittance of 90% or more and 380 mm transmittance of 30% or less, and the retardation film 1, the polarizer 3 and the transparent protective film 5 are adjacent to each other through adhesive layers 2 and 4.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to an optical laminate, a roll of the optical laminate, an elliptical polarizing plate including the optical laminate, and an organic EL display device.

Background Art

[0002] An elliptical polarizing plate is an optical member in which a polarizing plate and a retardation plate are laminated. For example, in a device that displays an image in a planar state such as an organic EL image display device, it is used to prevent light reflection at the electrodes that make up the device. As the retardation plate that constitutes this elliptical polarizing plate, a so-called λ / 4 plate is generally used. As such a retardation plate, a retardation plate using a liquid crystal cured film produced by applying a polymerizable liquid crystal compound on a substrate and curing it is known (Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In recent years, there has been a demand for flexible displays, and an elliptical polarizing plate that is thin and has high flexibility is required. From the viewpoint of realizing thinning, a retardation film obtained by curing a polymerizable liquid crystal compound as described in Cited Document 1 is suitable for a flexible display, and an elliptical polarizing plate (film) can be produced by transferring a retardation plate (film) formed from such a liquid crystal cured film to a polarizing plate via a pressure-sensitive adhesive. However, when the present inventors transfer a retardation plate formed from a liquid crystal cured film using a pressure-sensitive adhesive, when the elliptical polarizing plate formed thereby is bent, strain is likely to occur at the bending point, and as a result, streak-like defects and an increase in the light reflectance from an oblique direction (oblique reflectance) may occur.

[0005] An object of the present invention is to provide an optical laminate that hardly generates strain when bent and is excellent in high flexibility and oblique reflectance, particularly an optical laminate suitable for a flexible display. [Means for Solving the Problems]

[0006] As a result of intensive studies to solve the above problems, the present inventors have completed the present invention. That is, the present invention includes the following aspects. [1] An optical laminate including a retardation film, a polarizer, and a transparent protective film in this order, wherein the retardation film includes a base film having a moisture permeability of 100 g / m 2 / 24 hours or more, and a liquid crystal cured film formed on the base film, having a thickness of 0.5 μm or more and 3 μm or less, and satisfying the following formulas (1) and (2): Re(450) / Re(550) ≦ 1.00 (1) 1.00 ≦ Re(650) / Re(550) (2) [In the formula, Re(λ) represents the in-plane retardation value at wavelength λ] and is filled with a single layer, and the polarizer is composed of a polyvinyl alcohol-based resin film containing a dichroic dye, the transparent protective film has a total light transmittance of 90% or more and a 380 nm transmittance of 30% or less, and the retardation film, the polarizer, and the transparent protective film are adjacent to each other via an adhesive layer. An optical laminate. [2] The optical laminate according to [1], wherein the base film has a total light transmittance of 90% or more and an absolute value of the retardation value Rth(550) in the thickness direction with respect to light of 550 nm of 5 nm or less. [3] The retardation film has an optical alignment film with a thickness of 10 nm or more and 1000 nm or less between the base film and the liquid crystal cured film, and the optical laminate according to [1] or [2] above. [4] The liquid crystal cured film is a film obtained by curing at least one compound having at least one maximum absorption between wavelengths of 300 to 400 nm, and the optical laminate according to any one of [1] to [3] above. [5] The liquid crystal cured film is represented by the following formula (3): 100 nm ≦ Re(550) ≦ 170 nm (3) [In the formula, Re(λ) represents the in-plane retardation value at wavelength λ] The optical laminate according to any one of [1] to [4] above, which satisfies the above. [6] The transparent protective film has a moisture permeability of 100 g / m 2 / 24 hours or more, and the optical laminate according to any one of [1] to [5] above. [7] The adhesive layer is a layer formed from a dry-curing type adhesive, and the optical laminate according to any one of [1] to [6] above. [8] The dry-curing type adhesive contains polyvinyl alcohol, and the optical laminate according to [7] above. [9] The retardation film is in contact with an adhesive layer that bonds the retardation film and the polarizer on the side of the liquid crystal cured film, and the optical laminate according to any one of [1] to [8] above.

[10] An optical laminate roll obtained by winding the optical laminate according to any one of [1] to [9] above.

[11] An elliptical polarizing plate containing the optical laminate according to any one of [1] to [9] above.

[12] An organic EL display device including the elliptical polarizing plate according to

[11] above.

[13] A flexible image display device including the elliptical polarizing plate according to

[11] above.

[14] The flexible image display device according to

[13] above, further including a window and a touch sensor.

Advantages of the Invention

[0007] According to the present invention, it is possible to provide an optical laminate that hardly generates strain when bent, has high flexibility, and is excellent in oblique reflectance, and in particular, an optical laminate suitable for a flexible display.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Embodiments for Carrying Out the Invention

[0009] Hereinafter, embodiments of the present invention will be described in detail. Note that the scope of the present invention is not limited to the embodiments described here, and various modifications can be made without departing from the spirit of the present invention.

[0010] The optical laminate of the present invention includes a retardation film, a polarizer, and a transparent protective film in this order, and the retardation film, the polarizer, and the transparent protective film are adjacent to each other via an adhesive layer, respectively.

[0011] (Adhesive layer) In the optical laminate of the present invention, the retardation film and the polarizer, and the polarizer and the transparent protective film are laminated via an adhesive layer, respectively. By laminating the retardation film and the polarizer, and the polarizer and the transparent protective film with an adhesive layer, respectively, when the obtained optical laminate is repeatedly bent, the deformation in the liquid crystal cured film constituting the retardation film and the deformation of the entire optical laminate are considered to easily follow each other, it is difficult to generate strain at the bending point, and it is possible to suppress streak-like defects and an increase in oblique reflectance caused by the strain.

[0012] The retardation film, the polarizer, and the adhesive layer that bonds the polarizer and the transparent protective film can be formed by an adhesive. Examples of adhesives that can form such an adhesive layer include drying and curing type adhesives such as aqueous adhesives, and chemical reaction type adhesives such as active energy ray curable adhesives. The adhesive layer that bonds the retardation film and the polarizer, and the polarizer and the transparent protective film may be formed from different adhesives, but it is preferably formed from the same adhesive.

[0013] Examples of the drying and curing type adhesive include polymers of monomers having a protic functional group such as a hydroxyl group, a carboxyl group or an amino group and an ethylenically unsaturated group, or compositions containing a urethane resin as a main component and further containing a crosslinking agent or a curable compound such as a polyvalent aldehyde, an epoxy compound, an epoxy resin, a melamine compound, a zirconia compound, and a zinc compound. Examples of the polymer of a monomer having a protic functional group such as a hydroxyl group, a carboxyl group or an amino group and an ethylenically unsaturated group include ethylene-maleic acid copolymer, itaconic acid copolymer, acrylic acid copolymer, acrylamide copolymer, saponified product of polyvinyl acetate, and polyvinyl alcohol-based resin.

[0014] Examples of the polyvinyl alcohol-based resin include polyvinyl alcohol, partially saponified polyvinyl alcohol, completely saponified polyvinyl alcohol, carboxyl group-modified polyvinyl alcohol, acetoacetyl group-modified polyvinyl alcohol, methylol group-modified polyvinyl alcohol, and amino group-modified polyvinyl alcohol. The content of the polyvinyl alcohol-based resin in the aqueous drying and curing type adhesive is usually 1 to 10 parts by mass, preferably 1 to 5 parts by mass, per 100 parts by mass of water.

[0015] Examples of the urethane resin include polyester-based ionomer urethane resins. The polyester-based ionomer urethane resin here refers to a urethane resin having a polyester backbone, in which a small amount of ionic component (hydrophilic component) is introduced. Such an ionomer urethane resin can be emulsified in water to form an emulsion without using an emulsifier, so it can be used as an aqueous drying and curing type adhesive. When using a polyester-based ionomer urethane resin, it is effective to blend a water-soluble epoxy compound as a crosslinking agent.

[0016] Examples of the epoxy resin include polyamide epoxy resins obtained by reacting epichlorohydrin with a polyamide polyamine obtained by reacting a polyalkylene polyamine such as diethylenetriamine or triethylenetetramine with a dicarboxylic acid such as adipic acid. Commercially available products of such polyamide epoxy resins include "Sumirez Resin (registered trademark) 650" and "Sumirez Resin (registered trademark) 675" (both manufactured by Sumitomo Chemical Tex Co., Ltd.), "WS-525" (manufactured by Nippon PMC Co., Ltd.), etc. When blending an epoxy resin, the addition amount is usually 1 to 100 parts by mass, preferably 1 to 50 parts by mass, based on 100 parts by mass of the polyvinyl alcohol-based resin.

[0017] Among them, it is preferable that the drying and curing type adhesive is an aqueous drying and curing type adhesive containing a polyvinyl alcohol-based resin.

[0018] The drying and curing type adhesive may contain a solvent. Examples of the solvent include water, a mixed solvent of water and a hydrophilic organic solvent (such as an alcohol solvent, an ether solvent, an ester solvent, etc.), and an organic solvent.

[0019] The active energy ray-curing type adhesive, which is a chemical reaction type adhesive, is an adhesive that cures upon irradiation with active energy rays. The active energy ray-curing type adhesive may contain a solvent. Examples of the active energy ray-curable adhesive include a cationic polymerizable adhesive containing an epoxy compound and a cationic polymerization initiator, a radical polymerizable adhesive containing an acrylic curing component and a radical polymerization initiator, an adhesive containing both a cationic polymerizable curing component such as an epoxy compound and a radical polymerizable curing component such as an acrylic compound, and further containing a cationic polymerization initiator and a radical polymerization initiator, and an adhesive that is cured by irradiating an electron beam without containing these polymerization initiators.

[0020] Among them, as the active energy ray-curable adhesive, a radical polymerizable active energy ray-curable adhesive containing an acrylic curing component and a radical polymerization initiator, and a cationic polymerizable active energy ray-curable adhesive containing an epoxy compound and a cationic polymerization initiator are preferable. Examples of the acrylic curing component include (meth)acrylates such as methyl (meth)acrylate and hydroxyethyl (meth)acrylate, and (meth)acrylic acid. The active energy ray-curable adhesive containing an epoxy compound may further contain a compound other than the epoxy compound. Examples of the compound other than the epoxy compound include oxetane compounds and acrylic compounds.

[0021] Examples of the radical polymerization initiator include the photopolymerization initiators described later that can be blended in the polymerizable liquid crystal composition for forming a liquid crystal cured film. Commercially available products of the cationic polymerization initiator include "Kayrad" (registered trademark) series (manufactured by Nippon Kayaku Co., Ltd.), "Silacure UVI" series (manufactured by Dow Chemical Company), "CPI" series (manufactured by San-Apro Ltd.), "TAZ", "BBI", and "DTS" (all of the above are manufactured by Midori Chemical Co., Ltd.), "Adeka Optomer" series (manufactured by ADEKA Corporation), "RHODORSIL" (registered trademark) (manufactured by Rhodia Corporation), and the like. The content of the radical polymerization initiator and the cationic polymerization initiator is usually 0.5 to 20 parts by mass, preferably 1 to 15 parts by mass, based on 100 parts by mass of the active energy ray-curable adhesive.

[0022] In an optical laminate formed by laminating a retardation film, a polarizer, and a transparent protective film in this order, from the viewpoints of reducing the thickness of the laminate and improving flexibility, it is considered advantageous to use an adhesive such as a dry-curing adhesive or a chemical reaction adhesive as compared with a pressure-sensitive adhesive formed from a highly viscous material. On the other hand, the optical laminate of the present invention includes a liquid crystal cured film that exhibits the optical properties represented by formulas (1) and (2) in a single layer. The polymerizable liquid crystal compound that forms such a liquid crystal cured film generally has a maximum absorption wavelength between 300 and 400 nm, as will be described later. Further, since the transparent protective film located on the viewing side when incorporated into an image display device has an ultraviolet absorption ability to protect the internal structure of the optical laminate from ultraviolet rays, in the production of an optical laminate having such a configuration, the irradiated ultraviolet rays may be absorbed by the liquid crystal cured film and the transparent protective film, and it may be difficult for a sufficient amount of ultraviolet rays to reach the inside of the laminate for curing the adhesive. Therefore, in the optical laminate of the present invention that can be configured to be sandwiched between layers having ultraviolet absorption ability (liquid crystal cured film and transparent protective film), using a dry-curing adhesive as an adhesive for bonding the retardation film and the polarizer, and the polarizer and the transparent protective film, is advantageous not only from the viewpoints of reducing the thickness and improving flexibility, but also from the viewpoint of obtaining an optical laminate with more excellent adhesion between layers.

[0023] The thicknesses of the adhesive layers for bonding the retardation film and the polarizer, and the polarizer and the transparent protective film are each preferably 10 nm or more, more preferably 30 nm or more, still more preferably 50 nm or more, and preferably 5 μm or less, more preferably 3 μm or less, still more preferably 2 μm or less. When the thickness of the adhesive layer is within the above range, when repeatedly bent, distortion at the bending point is less likely to occur, and it is easy to suppress the occurrence of streak-like defects and the increase in oblique reflectance caused thereby. The thicknesses of the adhesive layers for bonding the retardation film and the polarizer, and the polarizer and the transparent protective film may be the same or different from each other. The thickness of the adhesive layer can be measured using, for example, an interference film thickness meter, a laser microscope, or a stylus type film thickness meter.

[0024] (Phase difference film) The phase difference film constituting the optical laminate of the present invention includes a base film having a moisture permeability of 100 g / m 2 / 24 hours or more and a liquid crystal cured film formed on the base film. The moisture permeability of the base film is preferably 150 g / m 2 / 24 hours or more, more preferably 200 g / m 2 / 24 hours or more. When the moisture permeability of the base film constituting the phase difference film is equal to or higher than the above lower limit, it becomes a configuration in which it is easy to control the moisture in the optical laminate formed by laminating the phase difference film with a polarizer. In particular, when a dry-curing type adhesive is used as the adhesive for forming the adhesive layer, it is easy to remove the solvent in the adhesive, and it is easy to prepare an adhesive layer having physical properties similar to the elasticity and flexibility of the liquid crystal cured film formed on the base film. Therefore, when the optical laminate is bent, the adhesive layer that adheres the respective layers hardly affects the deformation in the liquid crystal cured film, and the deformation of the entire optical laminate and the deformation in each layer are likely to follow each other. As a result, even when repeatedly bent, the generation of strain at the bending point hardly occurs, and streak-like defects and an increase in oblique reflectance caused thereby can be suppressed. The upper limit of the moisture permeability of the base film is not particularly limited, but is usually 1000 g / m 2 / 24 hours or less, preferably 500 g / m 2 / 24 hours or less. Incidentally, the moisture permeability of the base film can be measured, for example, by JIS Z 0208 (cup method). Specifically, it can be measured according to the method described in the examples described later.

[0025] The moisture permeability of the base film can be controlled by the type of resin constituting the film, the thickness of the film, surface treatment, and the like.

[0026] 100 g / m 2Examples of the resin constituting the base film having a moisture permeability of 24 hours or more include triacetyl cellulose, polyvinyl pyrrolidone-based polymers, (meth)acrylamide-based polymers, etc. From the viewpoint of easy availability, etc., triacetyl cellulose is preferred. Such a resin can be formed into a base film by a known means such as a solvent casting method or a melt extrusion method. Also, commercially available products may be used.

[0027] The thickness of the base film can be appropriately determined according to the configuration of the desired optical laminate. From the viewpoints of thinning of the optical laminate, processability, flexibility, strength, etc., it is usually 5 μm to 300 μm, preferably 15 μm to 200 μm, more preferably 20 μm to 150 μm.

[0028] The base film preferably has a total light transmittance of 90% or more, more preferably 92% or more. When the total light transmittance is at least the above lower limit value, an optical laminate with high transparency and excellent optical properties can be formed. The upper limit value of the total light transmittance in the base film is not particularly limited as long as it is 100% or less. The total light transmittance can be measured, for example, in accordance with JIS K 7361.

[0029] The base film preferably has an absolute value of the retardation value Rth(550) in the thickness direction with respect to light of 550 nm of 5 nm or less, more preferably 3 nm or less. By controlling the retardation value in the thickness direction of the base film, it is difficult to affect the optical properties expected by the liquid crystal cured film, and the diagonal reflectance of the obtained optical laminate can be suppressed low. Such an optical laminate is excellent in suppressing light leakage and hue change during black display when incorporated into a display device, etc., and thus becomes an optical laminate advantageous in optical properties. The smaller the retardation value Rth(550) of the base film, the more preferable, and it may be 0 nm. The retardation value Rth(550) of the base film can be controlled by blending additives, and can also be controlled by a casting method or the like.

[0030] On the surface of the base film, depending on components that form a liquid crystal cured film or an alignment film, components of an adhesive that can come into contact with the base film, etc., surface treatments such as corona treatment or plasma treatment may be performed to enhance adhesion and the like with these components.

[0031] In the present invention, the liquid crystal cured film constituting the retardation film is represented by the following formulas (1) and (2): Re(450) / Re(550)≦1.00 (1) 1.00≦Re(650) / Re(550) (2) [In the formula, Re(λ) represents the in-plane retardation value at wavelength λ] It is a liquid crystal cured film that satisfies the above with a single layer. "Satisfies with a single layer" means that a single cured film obtained from a polymerizable liquid crystal compound containing a liquid crystal compound is a single layer and exhibits the optical characteristics represented by the above formulas (1) and (2).

[0032] When the liquid crystal cured film satisfies formulas (1) and (2), the liquid crystal cured film exhibits so-called inverse wavelength dispersion in which the in-plane retardation value at a short wavelength is smaller than the in-plane retardation value at a long wavelength. When exhibiting inverse wavelength dispersion, it tends to easily exhibit uniform retardation performance in a wide wavelength range of visible light, and the optical characteristics of the optical laminate tend to be improved. By using a liquid crystal cured film having optical characteristics that satisfy the above formulas (1) and (2) with a single layer (hereinafter, also referred to as "liquid crystal cured film (x)"), a thinner retardation film with excellent optical characteristics can be obtained.

[0033] Since the inverse wavelength dispersion is improved and the effect of improving the reflection hue in the front direction of the liquid crystal cured film can be further enhanced, Re(450) / Re(550) is preferably 0.70 or more, more preferably 0.78 or more, and preferably 0.95 or less, more preferably 0.92 or less. Also, Re(650) / Re(550) is preferably 1.0 or more, more preferably 1.01 or more, and even more preferably 1.02 or more.

[0034] The in-plane retardation value can be adjusted by the thickness d1 of the liquid crystal cured film. Since the in-plane retardation value of the liquid crystal cured film is determined by Re = (nx(λ) - ny(λ)) × d (where d represents the thickness of the liquid crystal cured film, nx represents the principal refractive index at a wavelength of λ nm in the direction parallel to the plane of the liquid crystal cured film in the refractive index ellipsoid formed by the liquid crystal cured film, and ny represents the refractive index at a wavelength of λ nm in the direction parallel to the plane of the liquid crystal cured film and orthogonal to the direction of nx in the refractive index ellipsoid formed by the liquid crystal cured film), in order to obtain a desired in-plane retardation value, the three-dimensional refractive index and the film thickness d may be adjusted.

[0035] Furthermore, the liquid crystal cured film (x) satisfies the following formula (3): 100 nm ≤ Re(550) ≤ 170 nm (3) 〔In the formula, Re(λ) represents the in-plane retardation value at a wavelength of λ〕 It is preferably satisfied. When the liquid crystal cured film (x) satisfies formula (3), when the optical laminate (elliptical polarizing plate) including the liquid crystal cured film (x) is applied to an organic EL display device, the front reflection hue during black display is likely to be improved. A more preferable range of the in-plane retardation value is 130 nm ≤ ReA(550) ≤ 150 nm.

[0036] In the present invention, the liquid crystal cured film (x) can be formed from a cured product of a polymerizable liquid crystal composition containing at least one polymerizable liquid crystal compound. The polymerizable liquid crystal compound is not particularly limited as long as it can form a liquid crystal cured film having desired optical properties, and a polymerizable liquid crystal compound conventionally known in the field of retardation films can be used.

[0037] The polymerizable liquid crystal compound is a liquid crystal compound having a polymerizable group. As the polymerizable liquid crystal compound, generally, polymers (cured products) obtained by polymerizing the polymerizable liquid crystal compound alone in an oriented state in a specific direction include a polymerizable liquid crystal compound exhibiting positive wavelength dispersion and a polymerizable liquid crystal compound exhibiting negative wavelength dispersion. From the viewpoint of easily obtaining a liquid crystal cured film that satisfies the optical characteristics represented by the above formulas (1) and (2) alone, in the present invention, the liquid crystal cured film (x) constituting the retardation film is preferably a cured product of a polymerizable liquid crystal composition containing a polymerizable liquid crystal compound in which the polymer (cured product) obtained by polymerizing alone in an oriented state in a specific direction exhibits negative wavelength dispersion.

[0038] The polymerizable group refers to a group that can participate in a polymerization reaction. The polymerizable group possessed by the polymerizable liquid crystal compound forming the liquid crystal cured film in the present invention is preferably a photopolymerizable group. The photopolymerizable group is a polymerizable group that can participate in a polymerization reaction by reactive species generated from a photopolymerization initiator, such as active radicals or acids. Examples of the photopolymerizable group include a vinyl group, a vinyloxy group, a 1-chlorovinyl group, an isopropenyl group, a 4-vinylphenyl group, an acryloyloxy group, a methacryloyloxy group, an oxiranyl group, and an oxetanyl group. Among them, an acryloyloxy group, a methacryloyloxy group, a vinyloxy group, an oxiranyl group, and an oxetanyl group are preferred, and an acryloyloxy group is more preferred.

[0039] The liquid crystallinity exhibited by the polymerizable liquid crystal compound may be thermotropic liquid crystal or lyotropic liquid crystal, but thermotropic liquid crystal is preferred in terms of enabling precise film thickness control. Also, as the phase order structure in thermotropic liquid crystal, nematic liquid crystal, smectic liquid crystal, or discotic liquid crystal may be used. The polymerizable liquid crystal compounds can be used alone or in combination of two or more.

[0040] A polymerizable liquid crystal compound having a so-called T-shaped or H-shaped molecular structure is likely to exhibit negative wavelength dispersion, and a polymerizable liquid crystal compound having a T-shaped molecular structure tends to exhibit stronger negative wavelength dispersion.

[0041] As the polymerizable liquid crystal compound exhibiting inverse wavelength dispersion, a compound having the following characteristics (A) to (D) is preferable. (A) It is a compound capable of forming a nematic phase or a smectic phase. (B) It has π electrons in the major axis direction (a) of the polymerizable liquid crystal compound. (C) It has π electrons in a direction (crossing direction (b)) crossing the major axis direction (a). (D) The π - electron density in the major axis direction (a) of the polymerizable liquid crystal compound defined by the following formula (i), where the total number of π electrons present in the major axis direction is N(πa) and the total molecular weight present in the major axis direction is N(Aa): D(πa)=N(πa) / N(Aa) (i) And the π - electron density in the crossing direction (b) of the polymerizable liquid crystal compound defined by the following formula (ii), where the total number of π electrons present in the crossing direction (b) is N(πb) and the total molecular weight present in the crossing direction (b) is N(Ab): D(πb)=N(πb) / N(Ab) (ii) And they satisfy the formula (iii) 0≦〔D(πa) / D(πb)〕<1 (iii) That is, the π - electron density in the crossing direction (b) is larger than the π - electron density in the major axis direction (a). As described above, a polymerizable liquid crystal compound having π electrons on the major axis and in the crossing direction with respect to it generally tends to have a T - shaped structure.

[0042] In the above characteristics (A) to (D), the major axis direction (a) and the number of π electrons N are defined as follows. · For a compound having a rod - like structure, for example, the major axis direction (a) is the long axis direction of the rod. · The number of π electrons N(πa) present in the major axis direction (a) does not include π electrons that disappear due to the polymerization reaction. · The number of π electrons N(πa) present in the major axis direction (a) is the total number of π electrons on the major axis and π electrons conjugated with it. For example, it includes the number of π electrons in a ring present in the major axis direction (a) that satisfies Hückel's rule. · The number of π electrons N(πb) present in the cross direction (b) does not include the π electrons that disappear due to the polymerization reaction. The polymerizable liquid crystal compound satisfying the above conditions has a mesogenic structure in the long axis direction. Due to this mesogenic structure, a liquid crystal phase (nematic phase, smectic phase) is expressed.

[0043] By heating the polymerizable liquid crystal compound satisfying the above (A) to (D) to a temperature equal to or higher than the phase transition temperature, it is possible to form a nematic phase or a smectic phase. In the nematic phase or smectic phase formed by the alignment of this polymerizable liquid crystal compound, usually, the long axis directions of the polymerizable liquid crystal compounds are aligned parallel to each other, and this long axis direction becomes the alignment direction of the nematic phase or smectic phase. When such a polymerizable liquid crystal compound is formed into a film and polymerized in a nematic phase or smectic phase state, a polymer film composed of a polymer polymerized in a state aligned in the long axis direction (a) can be formed. This polymer film absorbs ultraviolet light by the π electrons in the long axis direction (a) and the π electrons in the cross direction (b). Here, let the absorption maximum wavelength of the ultraviolet light absorbed by the π electrons in the cross direction (b) be λbmax. λbmax is usually 300 nm to 400 nm. Since the density of π electrons satisfies the above formula (iii) and the π electron density in the cross direction (b) is larger than the π electron density in the long axis direction (a), the absorption of linearly polarized ultraviolet light (wavelength is λbmax) having a vibration plane in the cross direction (b) is larger than that of linearly polarized ultraviolet light (wavelength is λbmax) having a vibration plane in the long axis direction (a), resulting in a polymer film. The ratio (the ratio of the absorbance in the cross direction (b) of linearly polarized ultraviolet light to the absorbance in the long axis direction (a)) is, for example, more than 1.0, preferably 1.2 or more, usually 30 or less, and for example, 10 or less.

[0044] The polymerizable liquid crystal compound having the above characteristics generally often shows inverse wavelength dispersion in the birefringence of the polymer when polymerized in a unidirectionally aligned state. Specifically, for example, a compound represented by the following formula (X) (hereinafter, also referred to as "polymerizable liquid crystal compound (X)") can be mentioned.

Chemical formula

[0045] In formula (X), Ar represents a divalent group having an aromatic group which may have a substituent. Examples of the aromatic group herein include the groups exemplified by (Ar-1) to (Ar-23) described later. Further, Ar may have two or more aromatic groups. At least one of a nitrogen atom, an oxygen atom, and a sulfur atom may be contained in the aromatic group. When there are two or more aromatic groups contained in Ar, the two or more aromatic groups may be bonded to each other by a divalent bonding group such as a single bond, -CO-O-, -O-. G 1 and G 2 each independently represent a divalent aromatic group or a divalent alicyclic hydrocarbon group. Here, the hydrogen atom contained in the divalent aromatic group or the divalent alicyclic hydrocarbon group may be substituted with a halogen atom, an alkyl group having 1 to 4 carbon atoms, a fluoroalkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a cyano group, or a nitro group, and the carbon atom constituting the divalent aromatic group or the divalent alicyclic hydrocarbon group may be substituted with an oxygen atom, a sulfur atom, or a nitrogen atom. L 1 、L 2 、B 1 and B 2 each independently represent a single bond or a divalent linking group. k and l each independently represent an integer of 0 to 3 and satisfy the relationship of 1 ≦ k + l. Here, when 2 ≦ k + l, B 1 and B 2 、G 1 and G 2 may be the same as or different from each other. E 1 and E 2 each independently represent an alkanediyl group having 1 to 17 carbon atoms, and an alkanediyl group having 4 to 12 carbon atoms is more preferable. Further, the hydrogen atom contained in the alkanediyl group may be substituted with a halogen atom, and -CH 2 - contained in the alkanediyl group may be substituted with -O-, -S-, -C(=O)-. P 1 and P 2Each independently represents a polymerizable group or a hydrogen atom, and at least one is a polymerizable group.

[0046] G 1 and G 2 each independently is preferably a 1,4-phenylene diyl group which may be substituted with at least one substituent selected from the group consisting of a halogen atom and an alkyl group having 1 to 4 carbon atoms, or a 1,4-cyclohexane diyl group which may be substituted with at least one substituent selected from the group consisting of a halogen atom and an alkyl group having 1 to 4 carbon atoms, more preferably a 1,4-phenylene diyl group substituted with a methyl group, an unsubstituted 1,4-phenylene diyl group, or an unsubstituted 1,4-trans-cyclohexane diyl group, particularly preferably an unsubstituted 1,4-phenylene diyl group or an unsubstituted 1,4-trans-cyclohexane diyl group. Also, at least one of a plurality of Gs 1 and G 2 is preferably a divalent alicyclic hydrocarbon group, and among Gs 1 or G 2 bonded to L 1 and G 2 it is more preferable that at least one is a divalent alicyclic hydrocarbon group.

[0047] L 1 and L 2 each independently is preferably a single bond, an alkylene group having 1 to 4 carbon atoms, -O-, -S-, -R a1 OR a2 -, -R a3 COOR a4 -, -R a5 OCOR a6 -, -R a7 OC=OOR a8 -, -N=N-, -CR c =CR d -, or -C≡C-. Here, R a1 ~R a8 each independently represents a single bond or an alkylene group having 1 to 4 carbon atoms, and R c and R drepresents an alkyl group having 1 to 4 carbon atoms or a hydrogen atom. L 1 and L 2 each independently represent, more preferably, a single bond, -OR a2-1 -, -CH 2 -, -CH 2 CH 2 -, -COOR a4-1 -, or -OCOR a6-1 -. Here, R a2-1 , R a4-1 , R a6-1 each independently represent a single bond, -CH 2 -, -CH 2 CH 2 -. L 1 and L 2 each independently represent, even more preferably, a single bond, -O-, -CH 2 CH 2 -, -COO-, -COOCH 2 CH 2 -.

[0048] B 1 and B 2 each independently represent, preferably, a single bond, an alkylene group having 1 to 4 carbon atoms, -O-, -S-, -R a9 OR a10 -, -R a11 COOR a12 -, -R a13 OCOR a14 -, or -R a15 OC=OOR a16 -. Here, R a9 ~R a16 each independently represent a single bond or an alkylene group having 1 to 4 carbon atoms. B 1 and B 2 each independently represent, more preferably, a single bond, -OR a10-1 -, -CH 2 -, -CH 2 CH 2 -, -COOR a12-1 -, or -OCOR a14-1 -. Here, R a10-1 , R a12-1 , R a14-1 each independently represent a single bond, -CH2 -, -CH 2 CH 2 represents any one of -. B 1 and B 2 are each independently, more preferably a single bond, -O-, -CH 2 CH 2 -, -COO-, -COOCH 2 CH 2 -, -OCO-, or -OCOCH 2 CH 2 -.

[0049] From the viewpoint of exhibiting inverse wavelength dispersion properties, it is preferable that 2 ≦ k + l ≦ 6, more preferably k + l = 4, and even more preferably k = 2 and l = 2. When k = 2 and l = 2, a symmetric structure is formed, which is preferable.

[0050] P 1 or P 2 Examples of the polymerizable group represented by include an epoxy group, a vinyl group, a vinyloxy group, a 1-chlorovinyl group, an isopropenyl group, a 4-vinylphenyl group, an acryloyloxy group, a methacryloyloxy group, an oxiranyl group, and an oxetanyl group. Among them, an acryloyloxy group, a methacryloyloxy group, a vinyl group, and a vinyloxy group are preferable, and an acryloyloxy group and a methacryloyloxy group are more preferable.

[0051] Ar preferably has at least one selected from an aromatic hydrocarbon ring which may have a substituent, an aromatic heterocyclic ring which may have a substituent, and an electron-withdrawing group. Examples of the aromatic hydrocarbon ring include a benzene ring, a naphthalene ring, an anthracene ring, etc., and a benzene ring and a naphthalene ring are preferred. Examples of the aromatic heterocyclic ring include a furan ring, a benzofuran ring, a pyrrole ring, an indole ring, a thiophene ring, a benzothiophene ring, a pyridine ring, a pyrazine ring, a pyrimidine ring, a triazole ring, a triazine ring, a pyrroline ring, an imidazole ring, a pyrazole ring, a thiazole ring, a benzothiazole ring, a thienothiazole ring, an oxazole ring, a benzoxazole ring, and a phenanthroline ring, etc. Among them, it is preferable to have a thiazole ring, a benzothiazole ring, or a benzofuran ring, and it is more preferable to have a benzothiazole ring. Further, when Ar contains a nitrogen atom, the nitrogen atom preferably has π electrons.

[0052] In formula (X), the total number N of π electrons of the group represented by Ar π is usually 6 or more, preferably 8 or more, more preferably 10 or more, still more preferably 14 or more, and particularly preferably 16 or more. Also, it is preferably 32 or less, more preferably 26 or less, and still more preferably 24 or less.

[0053] Examples of the aromatic group contained in Ar include the following groups.

[0054]

Chemical formula

[0055] In formulas (Ar-1) to (Ar-23), the * mark represents a connecting part, and Z 0 , Z 1 and Z 2Each independently represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 12 carbon atoms, a cyano group, a nitro group, an alkylsulfinyl group having 1 to 12 carbon atoms, an alkylsulfonyl group having 1 to 12 carbon atoms, a carboxyl group, a fluoroalkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, an alkylthio group having 1 to 12 carbon atoms, an N-alkylamino group having 1 to 12 carbon atoms, an N,N-dialkylamino group having 2 to 12 carbon atoms, an N-alkylsulfamoyl group having 1 to 12 carbon atoms or an N,N-dialkylsulfamoyl group having 2 to 12 carbon atoms. Further, Z 0 Z 1 and Z 2 may contain a polymerizable group.

[0056] Q 1 and Q 2 each independently represents -CR 2’ R 3’ -, -S-, -NH-, -NR 2’ -, -CO- or -O-, and R 2’ and R 3’ each independently represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms.

[0057] J 1 and J 2 each independently represents a carbon atom or a nitrogen atom.

[0058] Y 1 Y 2 and Y 3 each independently represents an optionally substituted aromatic hydrocarbon group or aromatic heterocyclic group.

[0059] W 1 and W 2 each independently represents a hydrogen atom, a cyano group, a methyl group or a halogen atom, and m represents an integer of 0 to 6.

[0060] Y 1 Y 2 and Y 3Examples of the aromatic hydrocarbon group include aromatic hydrocarbon groups having 6 to 20 carbon atoms such as phenyl group, naphthyl group, anthryl group, phenanthryl group, biphenyl group, etc., with phenyl group and naphthyl group being preferred, and phenyl group being more preferred. Examples of the aromatic heterocyclic group include aromatic heterocyclic groups having 4 to 20 carbon atoms containing at least one hetero atom such as nitrogen atom, oxygen atom, sulfur atom, etc., such as furyl group, pyrrolyl group, thienyl group, pyridinyl group, thiazolyl group, benzothiazolyl group, etc., with furyl group, thienyl group, pyridinyl group, thiazolyl group, benzothiazolyl group being preferred.

[0061] Y 1 、Y 2 およびY 3 may each independently be an optionally substituted polycyclic aromatic hydrocarbon group or polycyclic aromatic heterocyclic group. The polycyclic aromatic hydrocarbon group refers to a condensed polycyclic aromatic hydrocarbon group or a group derived from an aromatic ring assembly. The polycyclic aromatic heterocyclic group refers to a condensed polycyclic aromatic heterocyclic group or a group derived from an aromatic ring assembly.

[0062] Z 0 、Z 1 およびZ 2 are each independently preferably a hydrogen atom, a halogen atom, an alkyl group having 1 to 12 carbon atoms, a cyano group, a nitro group, an alkoxy group having 1 to 12 carbon atoms, and Z 0 is more preferably a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, a cyano group, and Z 1 およびZ 2 are more preferably a hydrogen atom, a fluorine atom, a chlorine atom, a methyl group, a cyano group. Also, Z 0 、Z 1 およびZ 2 may contain a polymerizable group.

[0063] Q 1 およびQ 2 are preferably -NH-, -S-, -NR 2’ -, -O-, and R 2’ is preferably a hydrogen atom. Among them, -S-, -O-, -NH- are particularly preferred.

[0064] Among formulas (Ar-1) to (Ar-23), formulas (Ar-6) and (Ar-7) are preferable from the viewpoint of the molecular stability.

[0065] In formulas (Ar-16) to (Ar-23), Y 1 may, together with the nitrogen atom to which it is bonded and Z 0 form an aromatic heterocyclic group. Examples of the aromatic heterocyclic group include those described above as the aromatic heterocyclic group that Ar may have. For example, a pyrrole ring, an imidazole ring, a pyrroline ring, a pyridine ring, a pyrazine ring, a pyrimidine ring, an indole ring, a quinoline ring, an isoquinoline ring, a purine ring, a pyrrolidine ring, etc. may be mentioned. This aromatic heterocyclic group may have a substituent. Also, Y 1 may, together with the nitrogen atom to which it is bonded and Z 0 be the above-described optionally substituted polycyclic aromatic hydrocarbon group or polycyclic aromatic heterocyclic group. For example, a benzofuran ring, a benzothiazole ring, a benzoxazole ring, etc. may be mentioned.

[0066] In the present invention, it is preferable that the liquid crystal cured film (x) constituting the retardation film has at least one maximum absorption between wavelengths of 300 to 400 nm, and the polymerizable liquid crystal compound for forming the liquid crystal cured film (x) is preferably a polymerizable liquid crystal compound having a maximum absorption wavelength between wavelengths of 300 to 400 nm. When a photopolymerization initiator is contained in the polymerizable liquid crystal composition, there is a possibility that the polymerization reaction and gelation of the polymerizable liquid crystal compound may progress during long-term storage. However, if the maximum absorption wavelength of the polymerizable liquid crystal compound is 300 to 400 nm, even if it is exposed to ultraviolet light during storage, the generation of reactive species from the photopolymerization initiator and the progress of the polymerization reaction and gelation of the polymerizable liquid crystal compound by the reactive species can be effectively suppressed. Therefore, it is advantageous in terms of the long-term stability of the polymerizable liquid crystal composition, and the alignment and film thickness uniformity of the obtained liquid crystal cured film can be improved. The maximum absorption wavelength of the polymerizable liquid crystal compound can be measured using an ultraviolet-visible spectrophotometer in a solvent. The solvent is a solvent capable of dissolving the polymerizable liquid crystal compound, and examples thereof include chloroform and tetrahydrofuran.

[0067] Examples of the polymerizable liquid crystal compound capable of forming the liquid crystal cured film (x) include polymerizable liquid crystal compounds as described in JP-A-2011-207765 and JP-A-2010-031223. Further, as long as the liquid crystal cured film (x) satisfying the above formulas (1) and (2) can be formed in a single layer, a polymerizable liquid crystal compound whose homopolymer exhibits positive wavelength dispersion may be used in an appropriate amount.

[0068] The content of the polymerizable liquid crystal compound in the polymerizable liquid crystal composition for forming the liquid crystal cured film (x) is, for example, 70 to 99.5 parts by mass, preferably 80 to 99 parts by mass, more preferably 85 to 98 parts by mass, and still more preferably 90 to 95 parts by mass with respect to 100 parts by mass of the solid content of the polymerizable liquid crystal composition. If the content of the polymerizable liquid crystal compound is within the above range, it is advantageous from the viewpoint of the alignment property of the obtained liquid crystal cured film (x). In the present specification, the solid content of the polymerizable liquid crystal composition means all components obtained by removing volatile components such as organic solvents from the polymerizable liquid crystal composition.

[0069] The polymerizable liquid crystal composition for forming the liquid crystal cured film (x) may further contain additives such as a solvent, a polymerization initiator, a leveling agent, an antioxidant, a photosensitizer, and a reactive additive in addition to the polymerizable liquid crystal compound. These components may be used alone or in combination of two or more.

[0070] Since the alignment liquid crystal composition is usually applied to a substrate film or the like in a state dissolved in a solvent, it preferably contains a solvent. As the solvent, it is preferable that the solvent can dissolve the polymerizable liquid crystal compound and is inert to the polymerization reaction of the polymerizable liquid crystal compound. Further, it is preferable that the solvent does not dissolve the substrate film to be used. Examples of the solvent include alcohol solvents such as water, methanol, ethanol, ethylene glycol, isopropyl alcohol, propylene glycol, ethylene glycol methyl ether, ethylene glycol butyl ether, 1-methoxy-2-propanol, 2-butoxyethanol, and propylene glycol monomethyl ether; ester solvents such as ethyl acetate, butyl acetate, ethylene glycol methyl ether acetate, γ-butyrolactone, propylene glycol methyl ether acetate, and ethyl lactate; ketone solvents such as acetone, methyl ethyl ketone, cyclopentanone, cyclohexanone, 2-heptanone, and methyl isobutyl ketone; aliphatic hydrocarbon solvents such as pentane, hexane, and heptane; alicyclic hydrocarbon solvents such as ethylcyclohexane; aromatic hydrocarbon solvents such as toluene, xylene, and anisole; nitrile solvents such as acetonitrile; ether solvents such as tetrahydrofuran and dimethoxyethane; chlorine-containing solvents such as chloroform and chlorobenzene; amide solvents such as dimethylacetamide, dimethylformamide, N-methyl-2-pyrrolidone (NMP), and 1,3-dimethyl-2-imidazolidinone. These solvents can be used alone or in combination of two or more. Among them, from the viewpoint of film coating, it is preferable to use at least one selected from alcohol solvents, ester solvents, ketone solvents, chlorine-containing solvents, amide solvents, and aromatic hydrocarbon solvents. From the viewpoint of the solubility of the polymerizable liquid crystal compound, it is more preferable to use at least one selected from ester solvents, ketone solvents, amide solvents, and aromatic hydrocarbon solvents.

[0071] The content of the solvent in the alignment liquid crystal composition is preferably 50 to 98 parts by mass, more preferably 70 to 95 parts by mass, with respect to 100 parts by mass of the alignment liquid crystal composition. Therefore, the solid content in 100 parts by mass of the alignment liquid crystal composition is preferably 2 to 50 parts by mass. When the solid content is 50 parts by mass or less, the viscosity of the alignment liquid crystal composition becomes low, so that the film thickness becomes substantially uniform and unevenness is less likely to occur. The above solid content can be appropriately determined in consideration of the thickness of the alignment liquid crystal cured film to be produced.

[0072] A polymerization initiator is a compound that generates reactive species by the contribution of heat or light and can initiate a polymerization reaction of a polymerizable liquid crystal compound or the like. Examples of the reactive species include active species such as radicals, cations, and anions. Among them, a photoinitiator that generates radicals by light irradiation is preferred from the viewpoint of easy reaction control.

[0073] Examples of the photoinitiator include benzoin compounds, benzophenone compounds, benzyl ketal compounds, oxime compounds, α-hydroxy ketone compounds, α-amino ketone compounds, triazine compounds, iodonium salts, and sulfonium salts, and commercially available products may be used. Specifically, Irgacure (registered trademark) 907, Irgacure 184, Irgacure 651, Irgacure 819, Irgacure 250, Irgacure 369, Irgacure 379, Irgacure 127, Irgacure 2959, Irgacure 754, Irgacure 379EG (all manufactured by BASF Japan Ltd.), Seikol BZ, Seikol Z, Seikol BEE (all manufactured by Seiko Chemical Co., Ltd.), Kayacure BP100 (manufactured by Nippon Kayaku Co., Ltd.), Kayacure UVI-6992 (manufactured by Dow), Adeka Optomer SP-152, Adeka Optomer SP-170, Adeka Optomer N-1717, Adeka Optomer N-1919, Adeka Arcles NCI-831, Adeka Arcles NCI-930 (all manufactured by Adeka Corporation), TAZ-A, TAZ-PP (all manufactured by Nippon Sieber Hegner Co., Ltd.), and TAZ-104 (manufactured by Sanwa Chemical Co., Ltd.). The photoinitiator contained in the alignment liquid crystal composition is at least one kind, and a plurality of kinds may be used in combination, and it may be appropriately selected in relation to the polymerizable liquid crystal compound contained in the polymerizable liquid crystal composition.

[0074] Since the photoinitiator can make full use of the energy emitted from the light source and is excellent in productivity, it preferably has a maximum absorption wavelength of 300 nm to 400 nm, more preferably 300 nm to 380 nm. Among them, α-acetophenone-based photoinitiators and oxime-based photoinitiators are preferred.

[0075] Examples of the α-acetophenone compound include 2-methyl-2-morpholino-1-(4-methylsulfanylphenyl)propan-1-one, 2-dimethylamino-1-(4-morpholinophenyl)-2-benzylbutan-1-one, and 2-dimethylamino-1-(4-morpholinophenyl)-2-(4-methylphenylmethyl)butan-1-one. More preferably, 2-methyl-2-morpholino-1-(4-methylsulfanylphenyl)propan-1-one and 2-dimethylamino-1-(4-morpholinophenyl)-2-benzylbutan-1-one are included. Commercially available products of the α-acetophenone compound include Irgacure 369, 379EG, 907 (all manufactured by BASF Japan Ltd.) and Seikool BEE (manufactured by Seiko Chemical Co., Ltd.).

[0076] Oxime ester-based photoinitiators generate radicals such as phenyl radicals and methyl radicals when irradiated with light. The polymerization of the polymerizable liquid crystal compound proceeds preferably by this radical. Among them, the oxime ester-based photoinitiator that generates methyl radicals is preferable in that the initiation efficiency of the polymerization reaction is high. Further, from the viewpoint of allowing the polymerization reaction to proceed more efficiently, it is preferable to use a photoinitiator that can efficiently utilize ultraviolet light having a wavelength of 350 nm or more. As the photoinitiator that can efficiently utilize ultraviolet light having a wavelength of 350 nm or more, a triazine compound or a carbazole compound containing an oxime ester structure is preferable, and a carbazole compound containing an oxime ester structure is more preferable from the viewpoint of sensitivity. Examples of the carbazole compound containing an oxime ester structure include 1,2-octanedione, 1-[4-(phenylthio)-2-(O-benzoyloxime)], ethanone, 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]-1-(O-acetyloxime), and the like. Commercially available products of the oxime ester-based photoinitiator include Irgacure OXE-01, Irgacure OXE-02, Irgacure OXE-03 (manufactured by BASF Japan Ltd.), Adeka Optomer N-1919, Adeka Arcles NCI-831 (manufactured by Adeka Corporation), and the like.

[0077] The content of the photoinitiator is usually 0.1 to 30 parts by mass, preferably 1 to 20 parts by mass, and more preferably 1 to 15 parts by mass with respect to 100 parts by mass of the polymerizable liquid crystal compound. Within the above range, the reaction of the polymerizable group proceeds sufficiently, and it is difficult to disturb the alignment of the polymerizable liquid crystal compound.

[0078] A leveling agent is an additive that adjusts the fluidity of a polymerizable liquid crystal composition and flattens the coating film obtained by applying the composition. For example, silicone-based, polyacrylate-based, and perfluoroalkyl-based leveling agents can be mentioned. Commercially available products may be used as the leveling agent. Specifically, DC3PA, SH7PA, DC11PA, SH28PA, SH29PA, SH30PA, ST80PA, ST86PA, SH8400, SH8700, FZ2123 (all of the above are manufactured by Toray Dow Corning Co., Ltd.), KP321, KP323, KP324, KP326, KP340, KP341, X22-161A, KF6001 (all of the above are manufactured by Shin-Etsu Chemical Co., Ltd.), TSF400, TSF401, TSF410, TSF4300, TSF4440, TSF4445, TSF-4446, TSF4452, TSF4460 (all of the above are manufactured by Momentive Performance Materials Japan LLC), Fluorinert (registered trademark) FC-72, FC-40, FC-43, FC-3283 (all of the above are manufactured by Sumitomo 3M Limited), Megafac (registered trademark) R-08, R-30, R-90, F-410, F-411, F-443, F-445, F-470, F-477, F-479, F-482, F-483, F-556 (all of the above are manufactured by DIC Corporation), F-Top (product name) EF301, EF303, EF351, EF352 (all of the above are manufactured by Mitsubishi Materials Electronic Chemicals Co., Ltd.), Surflon (registered trademark) S-381, S-382, S-383, S-393, SC-101, SC-105, KH-40, SA-100 (all of the above are manufactured by AGC Seimi Chemical Co., Ltd.), product name E1830, E5844 (manufactured by Daikin Fine Chemical Research Institute Co., Ltd.), BM-1000, BM-1100, BYK-352, BYK-353, and BYK-361N (all of the above are product names: manufactured by BM Chemie) and the like can be mentioned. The leveling agent can be used alone or in combination of two or more.

[0079] The content of the leveling agent is preferably 0.01 to 5 parts by mass, more preferably 0.05 to 3 parts by mass, per 100 parts by mass of the polymerizable liquid crystal compound. When the content of the leveling agent is within the above range, it is easy to orient the polymerizable liquid crystal compound, and the resulting liquid crystal cured film tends to be smoother, which is preferable.

[0080] By blending an antioxidant, the polymerization reaction of the polymerizable liquid crystal compound can be controlled. The antioxidant may be a primary antioxidant selected from phenolic antioxidants, amine antioxidants, quinone antioxidants, and nitroso antioxidants, or a secondary antioxidant selected from phosphorus antioxidants and sulfur antioxidants. In order to polymerize the polymerizable liquid crystal compound without disturbing its orientation, the content of the antioxidant is usually 0.01 to 10 parts by mass, preferably 0.1 to 5 parts by mass, and more preferably 0.1 to 3 parts by mass, per 100 parts by mass of the polymerizable liquid crystal compound. The antioxidants can be used alone or in combination of two or more.

[0081] By using a photosensitizer, the photosensitive initiator can be made highly sensitive. Examples of the photosensitizer include xanthones such as xanthone and thioxanthone; anthracenes having substituents such as anthracene and alkyl ether; phenothiazine; and rubrene. The photosensitizers can be used alone or in combination of two or more. The content of the photosensitizer is usually 0.01 to 10 parts by mass, preferably 0.05 to 5 parts by mass, and more preferably 0.1 to 3 parts by mass, per 100 parts by mass of the polymerizable liquid crystal compound.

[0082] By using a reactive additive, the adhesion between the substrate film and the liquid crystal cured film and the adhesion between the retardation film and the adhesive layer can be improved. As the reactive additive, those having a carbon-carbon unsaturated bond and an active hydrogen reactive group in the molecule are preferable. Here, the "active hydrogen reactive group" refers to a carboxyl group (-COOH), a hydroxyl group (-OH), an amino group (-NH 2It means a group having reactivity with a group having active hydrogen such as etc., and representative examples thereof include a glycidyl group, an oxazoline group, a carbodiimide group, an aziridine group, an imide group, an isocyanate group, a thioisocyanate group, a maleic anhydride group and the like. The number of carbon-carbon unsaturated bonds or active hydrogen-reactive groups possessed by the reactive additive is usually 1 to 20, preferably 1 to 10 respectively.

[0083] In the reactive additive, it is preferable that at least two active hydrogen-reactive groups are present. In this case, the plurality of active hydrogen-reactive groups may be the same or different.

[0084] The carbon-carbon unsaturated bond possessed by the reactive additive may be a carbon-carbon double bond, a carbon-carbon triple bond, or a combination thereof, but a carbon-carbon double bond is preferable. Among them, as the reactive additive, it is preferable to contain a carbon-carbon unsaturated bond as a vinyl group and / or a (meth)acrylic group. Further, a reactive additive in which the active hydrogen-reactive group is at least one selected from the group consisting of an epoxy group, a glycidyl group and an isocyanate group is preferable, and a reactive additive having an acrylic group and an isocyanate group is more preferable.

[0085] Specific examples of the reactive additive include compounds having a (meth)acrylic group and an epoxy group, such as glycidyl methacrylate and glycidyl acrylate; compounds having a (meth)acrylic group and an oxetane group, such as oxetane acrylate and oxetane methacrylate; compounds having a (meth)acrylic group and a lactone group, such as lactone acrylate and lactone methacrylate; compounds having a vinyl group and an oxazoline group, such as vinyl oxazoline and isopropenyl oxazoline; oligomers of compounds having a (meth)acrylic group and an isocyanate group, such as isocyanatomethyl acrylate, isocyanatomethyl methacrylate, 2-isocyanatoethyl acrylate, or 2-isocyanatoethyl methacrylate. Also included are compounds having a vinyl group or vinylene group and an acid anhydride, such as methacrylic anhydride, acrylic anhydride, maleic anhydride, or vinyl maleic anhydride. Among them, glycidyl methacrylate, glycidyl acrylate, isocyanatomethyl acrylate, isocyanatomethyl methacrylate, vinyl oxazoline, 2-isocyanatoethyl acrylate, 2-isocyanatoethyl methacrylate, or the above oligomers are preferred, and isocyanatomethyl acrylate, 2-isocyanatoethyl acrylate, or the above oligomers are particularly preferred.

[0086] As the reactive additive, commercially available products can be used as they are or purified as necessary. Examples of commercially available products include Laromer (registered trademark) LR-9000 (manufactured by BASF).

[0087] When the polymerizable liquid crystal composition contains a reactive additive, the content of the reactive additive is usually 0.01 to 10 parts by mass, preferably 0.1 to 7 parts by mass, per 100 parts by mass of the polymerizable liquid crystal compound.

[0088] The polymerizable liquid crystal composition for forming the liquid crystal cured film (x) can be obtained by stirring the polymerizable liquid crystal compound and components such as a solvent and a polymerization initiator at a predetermined temperature.

[0089] The liquid crystal cured film (x) is, for example, forming a coating film of a polymerizable liquid crystal composition containing at least one kind of polymerizable liquid crystal compound on a substrate film or an alignment film described later, drying the coating film, and aligning the polymerizable liquid crystal compound in the polymerizable liquid crystal composition, and a step of polymerizing the polymerizable liquid crystal compound while maintaining the alignment state to form a liquid crystal cured film can be manufactured by a method including this.

[0090] The coating film of the polymerizable liquid crystal composition can be formed by applying the polymerizable liquid crystal composition on a substrate film or an alignment film formed on the substrate film as described later.

[0091] Examples of the method for applying the polymerizable liquid crystal composition to a substrate film or the like include known methods such as a spin coating method, an extrusion method, a gravure coating method, a die coating method, a bar coating method, an applicator method, and other coating methods, and printing methods such as a flexo method.

[0092] Next, by removing the solvent by drying or the like, a dry coating film is formed. Examples of the drying method include natural drying, ventilation drying, heat drying, and reduced-pressure drying methods. At this time, by heating the coating film obtained from the polymerizable liquid crystal composition, the solvent can be dried and removed from the coating film, and the polymerizable liquid crystal compound can be oriented in a desired direction such as a horizontal direction with respect to the plane of the coating film. The heating temperature of the coating film can be appropriately determined in consideration of the polymerizable liquid crystal compound used and the material of the base film or the like for forming the coating film. However, in order to cause the polymerizable liquid crystal compound to undergo a phase transition to the liquid crystal phase state, it is usually necessary to be at a temperature equal to or higher than the liquid crystal phase transition temperature. In order to obtain a desired orientation state of the polymerizable liquid crystal compound while removing the solvent contained in the polymerizable liquid crystal composition, for example, it can be heated to a temperature equal to or higher than the liquid crystal phase transition temperature (smectic phase transition temperature or nematic phase transition temperature) of the polymerizable liquid crystal compound contained in the polymerizable liquid crystal composition. The heating temperature is preferably 3°C or more, more preferably 5°C or more, higher than the liquid crystal phase transition temperature of the polymerizable liquid crystal compound. The upper limit value of the heating temperature is not particularly limited, but in order to avoid damage to the coating film, the base film, etc. due to heating, it is preferably 180°C or lower, more preferably 150°C or lower. The liquid crystal phase transition temperature can be measured, for example, using a polarizing microscope equipped with a temperature control stage, a differential scanning calorimeter (DSC), a thermogravimetric differential thermal analyzer (TG-DTA), or the like. When two or more polymerizable liquid crystal compounds are used in combination, the above phase transition temperature means the temperature measured in the same manner as when using one polymerizable liquid crystal compound, using a mixture of polymerizable liquid crystal compounds in which all the polymerizable liquid crystal compounds constituting the polymerizable liquid crystal composition are mixed at the same ratio as in the polymerizable liquid crystal composition. It is also known that generally, the liquid crystal phase transition temperature of the polymerizable liquid crystal compound in the polymerizable liquid crystal composition may be lower than the liquid crystal phase transition temperature of the polymerizable liquid crystal compound alone.

[0093] The heating time can be appropriately determined according to the heating temperature, the type of the polymerizable liquid crystal compound used, the type of the solvent, its boiling point, and its amount, etc. Usually, it is 0.5 to 10 minutes, preferably 0.5 to 5 minutes.

[0094] Removal of the solvent from the coating film may be carried out simultaneously with heating to a temperature equal to or higher than the liquid crystal phase transition temperature of the polymerizable liquid crystal compound, or may be carried out separately, but it is preferably carried out simultaneously from the viewpoint of productivity improvement. Before heating to a temperature equal to or higher than the liquid crystal phase transition temperature of the polymerizable liquid crystal compound, a preliminary drying step may be provided to appropriately remove the solvent in the coating film under conditions where the polymerizable liquid crystal compound contained in the coating film obtained from the polymerizable liquid crystal composition does not polymerize. Examples of the drying method in such a preliminary drying step include natural drying method, ventilation drying method, heat drying, and vacuum drying method, etc. The drying temperature (heating temperature) in the drying step can be appropriately determined according to the type of the polymerizable liquid crystal compound used, the type of the solvent, its boiling point, and its amount, etc.

[0095] Next, in the obtained dry coating film, while maintaining the alignment state of the polymerizable liquid crystal compound, the polymerizable liquid crystal compound is polymerized by light irradiation, thereby forming a liquid crystal cured film that is a polymer of the polymerizable liquid crystal compound present in a desired alignment state. As the polymerization method, a photopolymerization method is usually used. In photopolymerization, the light irradiated on the dry coating film is appropriately selected according to the type of the photopolymerization initiator contained in the dry coating film, the type of the polymerizable liquid crystal compound (particularly, the type of the polymerizable group possessed by the polymerizable liquid crystal compound), and its amount. Specific examples thereof include one or more types of light selected from the group consisting of visible light, ultraviolet light, infrared light, X-rays, α-rays, β-rays, and γ-rays, and active energy rays such as active electron beams. Among them, ultraviolet light is preferable in terms of being easy to control the progress of the polymerization reaction and the fact that those widely used in the art can be used as the photopolymerization apparatus. It is preferable to select the types of the polymerizable liquid crystal compound and the photopolymerization initiator contained in the polymerizable liquid crystal composition so that they can be photopolymerized by ultraviolet light. Further, during polymerization, the polymerization temperature can also be controlled by irradiating light while cooling the dry coating film by an appropriate cooling means. By adopting such a cooling means, if the polymerization of the polymerizable liquid crystal compound is carried out at a lower temperature, even if a substrate with relatively low heat resistance is used, a liquid crystal cured film can be appropriately formed. Also, it is possible to promote the polymerization reaction by increasing the polymerization temperature within a range where problems due to heat during light irradiation (such as deformation of the substrate film due to heat) do not occur. During photopolymerization, a patterned cured film can also be obtained by performing masking, development, etc.

[0096] Examples of the light source for the active energy rays include low-pressure mercury lamps, medium-pressure mercury lamps, high-pressure mercury lamps, ultra-high-pressure mercury lamps, xenon lamps, halogen lamps, carbon arc lamps, tungsten lamps, gallium lamps, excimer lasers, LED light sources that emit light in the wavelength range of 380 to 440 nm, chemical lamps, black light lamps, microwave-excited mercury lamps, metal halide lamps, and the like.

[0097] The ultraviolet irradiation intensity is usually 10 to 3,000 mW / cm 2It is so. The ultraviolet irradiation intensity is preferably the intensity in the wavelength region effective for activating the photopolymerization initiator. The time for irradiating light is usually from 0.1 second to 10 minutes, preferably from 0.1 second to 5 minutes, more preferably from 0.1 second to 3 minutes, and still more preferably from 0.1 second to 1 minute. When irradiated once or a plurality of times with such an ultraviolet irradiation intensity, the integrated light quantity is 10 to 3,000 mJ / cm 2 , preferably 50 to 2,000 mJ / cm 2 , more preferably 100 to 1,000 mJ / cm 2 .

[0098] The thickness of the liquid crystal cured film (x) is 0.5 μm or more and 3 μm or less, more preferably 1.0 μm or more, and still more preferably 1.5 μm or more. Also, it is more preferably 2.5 μm or less. When the film thickness of the liquid crystal cured film (x) is within the above range, it is easy to exhibit predetermined optical characteristics, and it is also easy to suppress the generation of strain at the bending point when repeatedly bent. The thickness of the liquid crystal cured film (x) can be measured using an interference film thickness meter, a laser microscope, a stylus type film thickness meter, or the like.

[0099] The liquid crystal cured film (x) may be formed on an alignment film. The alignment film has an alignment regulating force for aligning the polymerizable liquid crystal compound in a desired direction. By forming the liquid crystal cured film using a horizontal alignment film having an alignment regulating force for aligning the polymerizable liquid crystal compound in the horizontal direction or a vertical alignment film having an alignment regulating force for aligning it in the vertical direction, the polymerizable liquid crystal compound can be aligned with higher accuracy in a desired direction, and a liquid crystal cured film exhibiting excellent optical characteristics when incorporated into a display device or the like can be obtained. The alignment regulating force can be arbitrarily adjusted depending on the type of the alignment film, the surface state, the rubbing conditions, etc. When the alignment film is formed from a photo-alignment polymer, it can be arbitrarily adjusted depending on the polarized light irradiation conditions, etc.

[0100] As the alignment film, those having solvent resistance that does not dissolve by application of a polymerizable liquid crystal composition or the like and also having heat resistance in heat treatment for removal of the solvent and alignment of the polymerizable liquid crystal compound are preferable. Examples of the alignment film include an alignment film containing an alignment polymer, a photo-alignment film, a groove alignment film having an uneven pattern or a plurality of grooves on the surface, and a stretched film stretched in the alignment direction. From the viewpoint of the accuracy of the alignment angle and quality, a photo-alignment film is preferable.

[0101] Examples of the alignment polymer include polyamides and gelatins having an amide bond in the molecule, polyimides having an imide bond in the molecule and polyamic acids which are hydrolysis products thereof, polyvinyl alcohol, alkyl-modified polyvinyl alcohol, polyacrylamide, polyoxazole, polyethyleneimine, polystyrene, polyvinylpyrrolidone, polyacrylic acid, and polyacrylic acid esters. Among them, polyvinyl alcohol is preferable. The alignment polymer can be used alone or in combination of two or more.

[0102] An alignment film containing an alignment polymer is usually obtained by applying a composition in which an alignment polymer is dissolved in a solvent (hereinafter also referred to as an "alignment polymer composition") to the surface on which an alignment film such as a base film is to be formed and removing the solvent, or by applying the alignment polymer composition to a substrate, removing the solvent, and rubbing (rubbing method). Examples of the solvent include the same solvents as those exemplified above as solvents that can be used for the polymerizable liquid crystal composition.

[0103] The concentration of the alignment polymer in the alignment polymer composition may be in a range in which the alignment polymer material can be completely dissolved in the solvent, but is preferably 0.1 to 20% in terms of solid content with respect to the solution, and more preferably about 0.1 to 10%.

[0104] As the alignment polymer composition, a commercially available alignment film material may be used as it is. Examples of the commercially available alignment film material include Sunever (registered trademark, manufactured by Nissan Chemical Industries, Ltd.) and Optomer (registered trademark, manufactured by JSR Corporation).

[0105] As a method of applying an alignment polymer composition to the surface on which an alignment film such as a substrate film is to be formed, the same methods as those exemplified as methods of applying a polymerizable liquid crystal composition to a substrate film can be mentioned.

[0106] As a method of removing the solvent contained in the alignment polymer composition, natural drying method, ventilation drying method, heat drying, and reduced pressure drying method, etc. can be mentioned.

[0107] In order to impart an alignment regulating force to the alignment film, a rubbing treatment can be carried out as necessary (rubbing method). As a method of imparting an alignment regulating force by the rubbing method, a method of bringing the film of the alignment polymer formed on the substrate surface into contact by applying the alignment polymer composition to the substrate and annealing it to a rubbing roll around which a rubbing cloth is wound and rotating can be mentioned. When performing the rubbing treatment, if masking is performed, a plurality of regions (patterns) having different alignment directions can also be formed on the alignment film.

[0108] A photoalignment film is usually obtained by applying a composition containing a polymer and / or monomer having a photoreactive group and a solvent (hereinafter, also referred to as "photoalignment film-forming composition") to the surface of a substrate film on which an alignment film is to be formed, removing the solvent, and then irradiating with polarized light (preferably, polarized UV). The photoalignment film is also advantageous in that the direction of the alignment regulating force can be arbitrarily controlled by selecting the polarization direction of the polarized light to be irradiated.

[0109] A photoreactive group means a group that generates liquid crystal alignment ability by light irradiation. Specifically, groups involved in photoreactions that are the origin of liquid crystal alignment ability such as molecular alignment induction or isomerization reaction, dimerization reaction, photocrosslinking reaction, or photodegradation reaction caused by light irradiation can be mentioned. Among them, groups involved in the dimerization reaction or photocrosslinking reaction are preferable in terms of excellent alignment properties. As the photoreactive group, a group having an unsaturated bond, particularly a double bond, is preferable, and a group having at least one selected from the group consisting of a carbon-carbon double bond (C=C bond), a carbon-nitrogen double bond (C=N bond), a nitrogen-nitrogen double bond (N=N bond), and a carbon-oxygen double bond (C=O bond) is particularly preferable.

[0110] Examples of the photoreactive group having a C═C bond include a vinyl group, a polyene group, a stilbene group, a stilbazoyl group, a stilbazolium group, a chalcone group, and a cinnamoyl group. Examples of the photoreactive group having a C═N bond include groups having structures such as an aromatic Schiff base and an aromatic hydrazone. Examples of the photoreactive group having an N═N bond include an azobenzene group, an azonaphthalene group, an aromatic heterocyclic azo group, a bisazo group, a formazan group, and a group having an azoxybenzene structure. Examples of the photoreactive group having a C═O bond include a benzophenone group, a coumarin group, an anthraquinone group, and a maleimide group. These groups may have substituents such as an alkyl group, an alkoxy group, an aryl group, an allyloxy group, a cyano group, an alkoxycarbonyl group, a hydroxyl group, a sulfonic acid group, and a halogenated alkyl group.

[0111] Among them, photoreactive groups involved in the photodimerization reaction are preferred. In terms of the fact that the photoreactive groups are preferably a cinnamoyl group and a chalcone group because the amount of polarized light irradiation required for photoalignment is relatively small, and a photoalignment film excellent in thermal stability and stability over time can be easily obtained. In particular, when the liquid crystal cured film is formed from a polymerizable liquid crystal compound having a (meth)acryloyloxy group as a polymerizable group, using a polymer having a cinnamoyl group in which the terminal portion of the polymer side chain has a cinnamic acid structure as the photoreactive group for forming the alignment film can improve the adhesion to the liquid crystal cured film.

[0112] Examples of the solvent contained in the composition for forming a photoalignment film include the same solvents as those exemplified above as solvents that can be used in a polymerizable liquid crystal composition, and can be appropriately selected according to the solubility of the polymer or monomer having a photoreactive group.

[0113] The content of the polymer or monomer having a photoreactive group in the composition for forming an optically aligned film can be appropriately adjusted according to the type of the polymer or monomer and the thickness of the intended optically aligned film, but it is preferably at least 0.2% by mass, more preferably in the range of 0.3 to 10% by mass, based on the mass of the composition for forming an optically aligned film. The composition for forming an optically aligned film may contain a polymer material such as polyvinyl alcohol or polyimide, and a photosensitizer, as long as the characteristics of the optically aligned film are not significantly impaired.

[0114] As a method for applying the composition for forming an optically aligned film to the surface on which the alignment film is to be formed, the same methods as those for applying an alignment polymer composition can be mentioned. Examples of the method for removing the solvent from the applied composition for forming an optically aligned film include a natural drying method, a ventilation drying method, a heat drying method, and a reduced pressure drying method.

[0115] To irradiate with polarized light, either in a form where polarized UV is directly irradiated onto the composition for forming an optically aligned film applied on the substrate film after removing the solvent, or in a form where polarized light is irradiated from the substrate film side and transmitted through the polarized light, may be used. Also, it is particularly preferable that the polarized light is substantially parallel light. The wavelength of the polarized light to be irradiated is preferably in the wavelength range where the photoreactive group of the polymer or monomer having a photoreactive group can absorb light energy. Specifically, UV (ultraviolet light) in the range of 250 to 400 nm in wavelength is particularly preferable. Examples of the light source used for the polarized light irradiation include a xenon lamp, a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, a metal halide lamp, and ultraviolet lasers such as KrF and ArF, and high-pressure mercury lamps, ultra-high-pressure mercury lamps, and metal halide lamps are more preferable. Among these, high-pressure mercury lamps, ultra-high-pressure mercury lamps, and metal halide lamps are preferable because they have a high emission intensity of ultraviolet light with a wavelength of 313 nm. By passing the light from the light source through an appropriate polarizer and irradiating, polarized UV can be irradiated. As such a polarizer, a polarizing filter, a polarizing prism such as a Glan-Thomson or Glan-Taylor prism, or a wire grid type polarizer can be used.

[0116] When rubbing or polarizing light irradiation is performed, if masking is performed, it is also possible to form a plurality of regions (patterns) having different liquid crystal alignment directions.

[0117] A groove alignment film is a film having an uneven pattern or a plurality of grooves on the film surface. When a polymerizable liquid crystal compound is applied to a film having a plurality of linear grooves arranged at equal intervals, the liquid crystal molecules are aligned in the direction along the grooves.

[0118] As a method for obtaining a groove alignment film, after exposure through an exposure mask having a slit in a pattern shape on the surface of a photosensitive polyimide film, development and rinsing treatments are performed to form an uneven pattern; a method of forming a layer of a UV curable resin before curing on a plate-shaped master having grooves on the surface, transferring the formed resin layer to a substrate, etc., and then curing; and a method of pressing a roll-shaped master having a plurality of grooves against a film of a UV curable resin before curing formed on the surface on which the alignment film is to be formed to form unevenness, and then curing, etc. can be mentioned.

[0119] The thickness of the alignment film (alignment film including an alignment polymer or photo-alignment film) is usually in the range of 10 nm or more and 10000 nm or less, preferably in the range of 10 nm or more and 2500 nm or less, more preferably in the range of 10 nm or more and 1000 nm or less, still more preferably in the range of 10 nm or more and 500 nm or less, and particularly preferably in the range of 50 nm or more and 250 nm or less.

[0120] (Polarizer) The polarizer that constitutes the optical laminate of the present invention is a film having a function of extracting linearly polarized light from incident natural light, and is a polyvinyl alcohol-based resin film containing a dichroic dye. As the polyvinyl alcohol-based resin that constitutes the polyvinyl alcohol-based resin film, a saponified product of a polyvinyl acetate-based resin can be used. Examples of the polyvinyl acetate-based resin include polyvinyl acetate, which is a homopolymer of vinyl acetate, and copolymers of vinyl acetate and other monomers copolymerizable therewith (for example, ethylene-vinyl acetate copolymer, etc.). Examples of other monomers copolymerizable with vinyl acetate include unsaturated carboxylic acids, olefins, vinyl ethers, unsaturated sulfonic acids, acrylamides having an ammonium group, and the like.

[0121] The saponification degree of the polyvinyl alcohol-based resin is usually about 85 to 100 mol%, preferably 98 mol% or more. The polyvinyl alcohol-based resin may be modified. For example, polyvinyl formal or polyvinyl acetal modified with aldehydes can also be used. The degree of polymerization of the polyvinyl alcohol-based resin is usually about 1,000 to 10,000, preferably in the range of 1,500 to 5,000.

[0122] A film formed from such a polyvinyl alcohol-based resin is used as the raw film of the polarizing film. The method for forming the polyvinyl alcohol-based resin film is not particularly limited, and the film can be formed by a known method. The film thickness of the polyvinyl alcohol-based raw film can be, for example, about 10 to 150 μm.

[0123] A polarizer is usually manufactured through a process of uniaxially stretching such a polyvinyl alcohol-based resin film, a process of adsorbing a dichroic dye by dyeing the polyvinyl alcohol-based resin film with the dichroic dye, a process of treating the polyvinyl alcohol-based resin film adsorbed with the dichroic dye with an aqueous boric acid solution, and a process of performing a water washing treatment after the treatment with the aqueous boric acid solution. Note that by dyeing the polyvinyl alcohol-based resin film with the dichroic dye, the dichroic dye will be contained in the polyvinyl alcohol-based resin film. When manufacturing a polarizer by such a manufacturing method, the polarizer becomes a stretched polyvinyl alcohol-based resin film containing a dichroic dye.

[0124] The uniaxial stretching of the polyvinyl alcohol-based resin film may be performed before the dyeing of the dichroic dye, may be performed simultaneously with the dyeing, or may be performed after the dyeing. When the uniaxial stretching is performed after the dyeing, this uniaxial stretching may be performed before the boric acid treatment or may be performed during the boric acid treatment. It is also possible to perform uniaxial stretching at these multiple stages. In the case of uniaxial stretching, it may be stretched uniaxially between rolls with different peripheral speeds, or may be stretched uniaxially using a hot roll. Also, the uniaxial stretching may be a dry stretching performed in the air, or may be a wet stretching performed using a solvent and stretching the polyvinyl alcohol-based resin film in a swollen state. From the viewpoint of suppressing the deformation of the polarizer, the stretching ratio is preferably 8 times or less, more preferably 7.5 times or less, and even more preferably 7 times or less. Also, from the viewpoint of expressing the function as a polarizer, the stretching ratio is usually 4.5 times or more. By setting the stretching ratio within the above range, the deformation of the polarizer over time can be suppressed.

[0125] As a method of dyeing a polyvinyl alcohol-based resin film with a dichroic dye, for example, a method of immersing the polyvinyl alcohol-based resin film in an aqueous solution containing the dichroic dye can be mentioned. As the dichroic dye, for example, iodine or a dichroic dye is used. The dichroic dye includes, for example, dichroic direct dyes composed of disazo compounds such as C.I.DIRECT RED 39, and dichroic direct dyes composed of trisazo, tetrakisazo compounds, etc. In addition, it is preferable that the polyvinyl alcohol-based resin film be subjected to an immersion treatment in water before the dyeing treatment.

[0126] When iodine is used as the dichroic dye, usually, a method of immersing the polyvinyl alcohol-based resin film in an aqueous solution containing iodine and potassium iodide for dyeing is adopted. The content of iodine in this aqueous solution is usually about 0.01 to 1 part by mass per 100 parts by mass of water. The content of potassium iodide is usually about 0.5 to 20 parts by mass per 100 parts by mass of water. The temperature of the aqueous solution used for dyeing is usually about 20 to 40°C. Also, the immersion time (dyeing time) in this aqueous solution is usually about 20 to 1,800 seconds. In addition, before immersing the polyvinyl alcohol-based resin film in the aqueous solution containing iodine and potassium iodide, in order to swell and facilitate dyeing, the film may be immersed in water. The temperature of such immersion treatment is usually 20 to 80°C, preferably 30 to 60°C, and the immersion time (dyeing time) is usually 20 to 1800 seconds.

[0127] On the other hand, when a dichroic organic dye is used as the dichroic dye, usually, a method of immersing the polyvinyl alcohol-based resin film in an aqueous solution containing a water-soluble dichroic dye for dyeing is adopted. The content of the dichroic organic dye in this aqueous solution is usually about 1×10 -4 ~10 parts by mass per 100 parts by mass of water, preferably 1×10 -3 ~1 part by mass, and more preferably 1×10 -3 ~1×10 -2It is a mass part. This aqueous solution may contain an inorganic salt such as sodium sulfate as a dyeing assistant. The temperature of the dichroic dye aqueous solution used for dyeing is usually about 20 to 80 °C. Also, the immersion time (dyeing time) in this aqueous solution is usually about 10 to 1,800 seconds.

[0128] The boric acid treatment after dyeing with the dichroic pigment can usually be carried out by a method of immersing the dyed polyvinyl alcohol-based resin film in an aqueous boric acid solution. The content of boric acid in this aqueous boric acid solution is usually about 2 to 15 parts by mass, preferably 5 to 12 parts by mass, per 100 parts by mass of water. When iodine is used as the dichroic pigment, this aqueous boric acid solution preferably contains potassium iodide, and the content of potassium iodide in that case is usually about 0.1 to 15 parts by mass, preferably 5 to 12 parts by mass, per 100 parts by mass of water. The immersion time in the aqueous boric acid solution is usually about 60 to 1,200 seconds, preferably 150 to 600 seconds, and more preferably 200 to 400 seconds. The temperature of the boric acid treatment is usually 50 °C or higher, preferably 50 to 85 °C, and more preferably 60 to 80 °C.

[0129] The polyvinyl alcohol-based resin film after the boric acid treatment is usually subjected to a water washing treatment. The water washing treatment can be carried out, for example, by a method of immersing the boric acid-treated polyvinyl alcohol-based resin film in water. The temperature of the water in the water washing treatment is usually about 5 to 40 °C. Also, the immersion time is usually about 1 to 120 seconds.

[0130] After the water washing, a drying treatment is performed to obtain a polarizer. The drying treatment can be carried out, for example, using a hot air dryer or a far-infrared heater. The temperature of the drying treatment is usually about 30 to 100 °C, preferably 50 to 80 °C. The time of the drying treatment is usually about 60 to 600 seconds, preferably 120 to 600 seconds. By the drying treatment, the moisture content of the polarizer is reduced to a practical level. The moisture content is usually about 5 to 20% by mass, preferably 8 to 15% by mass. When the moisture content is within the above range, a polarizer having appropriate flexibility and excellent thermal stability can be obtained.

[0131] In this way, it is obtained by uniaxially stretching a polyvinyl alcohol-based resin film, dyeing with a dichroic dye, treating with boric acid, washing with water, and drying.

[0132] The thickness of the polarizer is preferably 5 to 40 μm, more preferably 5 to 20 μm.

[0133] (Transparent protective film) The optical laminate of the present invention includes a transparent protective film laminated via an adhesive layer on the surface of the polarizer opposite to the retardation film. Since the polarizer has a thin film thickness and its surface is easily damaged, usually, protective films are provided on both sides of the polarizer to prevent damage and dirt from the outside. However, in the optical laminate of the present invention, no protective film is laminated on the surface of the polarizer on the side of the retardation film. As a result, an optical laminate that is thinner and has a lower oblique reflectance can be obtained.

[0134] In the present invention, the transparent protective film has a total light transmittance of 90% or more, more preferably 92% or more. When the total light transmittance is equal to or higher than the above lower limit value, an optical laminate with high transparency and excellent optical properties can be formed. The upper limit value of the total light transmittance in the base film is not particularly limited and may be 100% or less. The total light transmittance can be measured, for example, in accordance with JIS K 7361.

[0135] Also, the transmittance at 380 nm in the transparent protective film is 30% or less, preferably 25% or less, more preferably 20% or less. When the transmittance at 380 nm of the transparent protective film is equal to or lower than the above upper limit, when the optical laminate including the transparent protective film is incorporated into an image display device, the layers (such as a polarizer and a liquid crystal cured film) constituting the inside of the optical laminate can be protected from ultraviolet rays exposed on the viewing side. The lower limit value of the transmittance at 380 nm of the transparent protective film is not particularly limited and may be 0%. In order to make the transmittance at 380 nm of the transparent protective film 30% or less, the transparent protective film may contain an ultraviolet absorber or the like. The transmittance at 380 nm can be measured, for example, in accordance with a spectrophotometer.

[0136] As the transparent protective film bonded to the polarizer via the adhesive layer, a known resin film can be used as long as it satisfies the above total light transmittance and 380 nm transmittance. Examples of the resin that can form the transparent protective film include polyolefins such as polyethylene, polypropylene, and norbornene-based polymers; cyclic olefin-based resins; polyvinyl alcohol; polyethylene terephthalate; polymethacrylic acid esters; polyacrylic acid esters; cellulose esters such as triacetyl cellulose, diacetyl cellulose, and cellulose acetate propionate; polyethylene naphthalate; polycarbonate; polysulfone; polyethersulfone; polyether ketone; polyphenylene sulfide; and polyphenylene oxide. Such a resin can be formed into a film by known means such as the solvent casting method or the melt extrusion method. The surface of the transparent protective film may be subjected to surface treatments such as release treatment like silicone treatment, corona treatment, and plasma treatment.

[0137] In one embodiment of the present invention, the transparent protective film preferably has a water vapor transmission rate of 100 g / m 2 / 24 h or more, more preferably 150 g / m 2 / 24 h or more, and even more preferably 200 g / m 2 / 24 h or more. When the water vapor transmission rate of the transparent protective film is at least the above lower limit value, when a retardation film and a polarizer are laminated using a dry-curing type adhesive to form an optical laminate, in addition to the base film constituting the retardation film, the solvent in the dry-curing type adhesive can be efficiently removed from the transparent protective film as well. As a result, when bent, the deformation in the liquid crystal cured film formed on the base film and the deformation as the optical laminate are more likely to follow each other, and an optical laminate in which generation of strain at the bending point is less likely to occur even when repeatedly bent can be obtained. Also, compared with the case where only the base film has a high water vapor transmission rate, the time for removing the solvent in the adhesive can be shortened, which may be advantageous in terms of productivity. The upper limit of the water vapor transmission rate of the transparent protective film is not particularly limited, but usually 1000 g / m2 / 24 hours or less, preferably 500 g / m 2 / 24 hours or less. The moisture permeability of the transparent protective film can be measured in the same manner as that of the base film.

[0138] 100 g / m 2 When using a transparent protective film having a moisture permeability of 100 g / m or more / 24 hours, the transparent protective film may be the same as or different from the base film.

[0139] The thickness of the transparent protective film can be appropriately determined according to the configuration of the desired optical laminate. However, from the viewpoints of thinning, processability, flexibility, strength, etc. of the optical laminate, it is usually 5 μm to 300 μm, preferably 20 μm to 200 μm, more preferably 20 μm to 150 μm.

[0140] Hereinafter, an example of the layer configuration of the optical laminate of the present invention will be described based on FIGS. 1 and 2, but the optical laminate of the present invention is not limited to these aspects. The optical laminate 100 shown in FIG. 1 includes a retardation film 1, a polarizer 3 laminated on one surface of the retardation film via an adhesive layer 2, and further, a transparent protective film 5 laminated on the surface of the polarizer 3 opposite to the retardation film 1 via an adhesive layer 4. In the optical laminate 100 shown in FIG. 1, the retardation film 1 is composed of a liquid crystal cured film 13 formed on a base film 11 via an alignment film 12.

[0141] The optical laminate of the present invention may be configured to include, in addition to a retardation film, a polarizer, a transparent protective film, and an adhesive layer for adhering these to each other, other layers having various functions that can be incorporated into an image display device or the like. However, no other layers are incorporated into the layer structure of the retardation film / adhesive layer / polarizer / adhesive layer / transparent protective film that are adjacent to each other. Examples of the other layers include, for example, an adhesive layer for incorporating the optical laminate into an image display device, and a second retardation film including a cured liquid crystal film having optical characteristics different from those of the cured liquid crystal film (x) such that the liquid crystal compound is oriented in the vertical direction with respect to the film surface.

[0142] In the present invention, the retardation film may be laminated with the polarizer via the adhesive layer on either the side of the base film or the cured liquid crystal film that constitutes the retardation film. For example, in the optical laminate 100 shown in FIG. 1, the base film 11 that constitutes the retardation film 1 is laminated with the polarizer 3 via the adhesive layer 2. On the other hand, in the optical laminate 100 shown in FIG. 2, the cured liquid crystal film 13 that constitutes the retardation film 1 is laminated with the polarizer 3 via the adhesive layer 2.

[0143] When the optical laminate of the present invention is incorporated into an image display device or the like, if the cured liquid crystal film (x) that constitutes the retardation film is not in contact with an adhesive layer for adhering the optical laminate to a member that constitutes an image display device such as an image display cell, the heat resistance of the optical laminate is likely to be improved. Therefore, in one embodiment of the present invention, it is preferable that the retardation film is in contact with an adhesive layer that adheres the retardation film and the polarizer on the side of the cured liquid crystal film that constitutes the retardation film.

[0144] The optical laminate of the present invention can be manufactured by laminating a retardation film, a polarizer, and a transparent protective film through an adhesive, respectively. When a dry-curing type adhesive is used as the adhesive, the dry-curing type adhesive is applied / injected onto the bonding surfaces of the retardation film, the polarizer, and / or the transparent protective film to form a laminate of retardation film / adhesive layer / polarizer / adhesive layer / transparent protective film. Then, the solvent in the adhesive is dried and removed from the laminate and cured, whereby each layer can be bonded.

[0145] This drying treatment and / or removal of the solvent can be performed, for example, by blowing hot air. The temperature depends on the type of the solvent, but is usually in the range of 30 to 200°C, preferably 35 to 150°C, more preferably 40 to 100°C, and still more preferably 50 to 100°C. Also, the drying time is usually about 10 seconds to 30 minutes.

[0146] When an active energy ray-curing type adhesive is used, an adhesive layer can be obtained by curing the active energy ray-curing type adhesive by irradiating active energy rays. The light source of the active energy rays is not particularly limited, but active energy rays having an emission distribution at a wavelength of 400 nm or less are preferable, and ultraviolet rays are more preferable. Specific examples of the light source include a low-pressure mercury lamp, a medium-pressure mercury lamp, a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, a chemical lamp, a black light lamp, a microwave-excited mercury lamp, and a metal halide lamp.

[0147] The light irradiation intensity on the active energy ray-curing type adhesive is appropriately determined according to the composition of the active energy ray-curing type adhesive and is not particularly limited. However, the irradiation intensity in the wavelength region effective for activating the polymerization initiator is usually 10 to 3,000 mW / cm 2It is as follows. The light irradiation time for the active energy ray-curable adhesive may be appropriately selected according to the active energy ray-curable adhesive to be cured, and is not particularly limited. Usually, it is 0.1 second to 10 minutes, preferably 1 second to 5 minutes, more preferably 5 seconds to 3 minutes, and still more preferably 10 seconds to 1 minute. When irradiated once or a plurality of times with such an ultraviolet irradiation intensity, the integrated light amount is usually 10 to 3,000 mJ / cm 2 preferably 50 to 2,000 mJ / cm 2 more preferably 100 to 1,000 mJ / cm 2 is as follows.

[0148] The optical laminate of the present invention can be continuously manufactured by a Roll to Roll method. For example, a retardation film including a substrate film wound in a roll shape and a liquid crystal cured film (x) is produced, and while unwinding and transporting this retardation film, a polarizer and a transparent protective film separately produced on the retardation film are sequentially laminated using an adhesive for bonding each layer, and then the adhesive is cured by drying or photocuring or the like, whereby it can be continuously manufactured. Therefore, in one embodiment of the present invention, the optical laminate of the present invention can be in the form of an optical laminate roll wound in a roll shape.

[0149] Since the optical laminate of the present invention including a retardation film and a polarizer can also be an elliptical polarizing plate, the present invention includes an elliptical polarizing plate including the optical laminate of the present invention.

[0150] In one embodiment of the present invention, it is preferable to laminate such that the angle formed by the slow axis (optical axis) of the liquid crystal cured film constituting the optical laminate and the polarizer of the present invention and the absorption axis of the polarizer is 45 ± 5°.

[0151] The elliptical polarizing plate of the present invention can be used for various display devices. A display device is a device having a display element and includes a light-emitting element or a light-emitting device as a light source. Examples of the display device include a liquid crystal display device, an organic electroluminescence (EL) display device, an inorganic electroluminescence (EL) display device, a touch panel display device, an electron emission display device (e.g., a field emission display device (FED), a surface field emission display device (SED)), an electronic paper (a display device using an electrochromic ink or an electrophoretic element), a plasma display device, a projection display device (e.g., a grating light valve (GLV) display device, a display device having a digital micromirror device (DMD)), and a piezoelectric ceramic display. The liquid crystal display device includes any of a transmissive liquid crystal display device, a transflective liquid crystal display device, a reflective liquid crystal display device, a direct-view liquid crystal display device, and a projection liquid crystal display device. These display devices may be a display device for displaying a two-dimensional image or a stereoscopic display device for displaying a three-dimensional image. In particular, the elliptical polarizing plate of the present invention can be preferably used for an organic electroluminescence (EL) display device and an inorganic electroluminescence (EL) display device, and the laminate of the present invention can be preferably used for a liquid crystal display device and a touch panel display device. By providing the laminate of the present invention in which unevenness in interference hardly occurs, these display devices can exhibit good image display characteristics.

[0152] In one embodiment of the present invention, the display device is preferably a flexible image display device, and the present invention also includes a flexible image display device including the elliptical polarizing plate of the present invention.

[0153] The flexible image display device having the elliptical polarizing plate of the present invention preferably further includes a window and a touch sensor. The flexible image display device includes, for example, a laminate for a flexible image display device and an organic EL display panel. The laminate for the flexible image display device is disposed on the viewing side with respect to the organic EL display panel and is configured to be foldable. As the laminate for the flexible image display device, in addition to the elliptical polarizing plate of the present invention described above, a window, a (touch panel) touch sensor, etc. may be included. The lamination order thereof is arbitrary, but it is preferably laminated in the order of a window, an elliptical polarizing plate, and a touch sensor, or in the order of a window, a touch sensor, and an elliptical polarizing plate from the viewing side.

[0154] It is preferable that an elliptical polarizing plate is present on the viewing side of the touch sensor because the pattern of the touch sensor is less likely to be visually recognized and the visibility of the display image is improved. Each member can be laminated using an adhesive, an adhesive agent, etc. Further, the laminate for the flexible image display device can include a light-shielding pattern formed on at least one surface of any layer of the window, the elliptical polarizing plate, and the touch sensor.

[0155] The window is disposed on the viewing side of the flexible image display device and plays a role of protecting other components from external impacts or environmental changes such as temperature and humidity. Conventionally, glass has been used as such a protective layer, but the window in the flexible image display device is not as rigid and hard as glass and has flexible characteristics. The window is made of a flexible transparent substrate and may include a hard coat layer on at least one surface.

[0156] The window, the touch sensor, etc. constituting the laminate for the flexible image display device are not particularly limited, and conventionally known ones can be adopted.

Example

[0157] Hereinafter, the present invention will be described more specifically by way of examples. In the examples, “%” and “parts” mean mass % and parts by mass, respectively, unless otherwise specified.

[0158] 〔Example 1〕 (1) Preparation of Composition for Forming Photoalignment Film 2 parts of Polymer (1) with a number average molecular weight of 28,000 represented by the following chemical formula and 98 parts of o-xylene were mixed, and the resulting mixture was stirred at 80 °C for 1 hour to obtain a composition for forming a photoalignment film.

[0159] Polymer (1) [Chemical Formula] [In the formula, Me represents a methyl group.]

[0160] (2) Preparation of Polymerizable Liquid Crystal Composition for Forming Liquid Crystal Hardened Film 86.0 parts of polymerizable liquid crystal compound A-1 having the following structure, 14.0 parts of polymerizable liquid crystal compound A-2, 0.12 part of polyacrylate compound (leveling agent / BYK-361N; manufactured by BYK-Chemie), 2-dimethylamino-2-benzyl-1-(4-morpholinophenyl)butan-1-one (photoinitiator / Irgacure 369; manufactured by Ciba Specialty Chemicals) (3.0 parts), and LALOMER LR9000 (manufactured by BASF Japan) (2.0 parts) were mixed. Further, anisole was added so that the solid content concentration became 9%. A polymerizable liquid crystal composition (A1) containing polymerizable liquid crystal compound A-1 and polymerizable liquid crystal compound A-2 was obtained. Note that polymerizable liquid crystal compound A-1 was synthesized by the method described in JP-A-2010-31223. The maximum absorption wavelength λmax(LC) of polymerizable liquid crystal compound A-1 measured in chloroform was 350 nm.

[0161] Polymerizable liquid crystal compound A-1: [Chemical Formula]

[0162] Polymerizable liquid crystal compound A-2: [Chemical Formula]

[0163] (3) Preparation of the retardation film A triacetyl cellulose film (KC4CZ-TAC, thickness 40 μm, manufactured by Konica Minolta) was processed once using a corona treatment apparatus (AGF-B10; manufactured by Kasuga Electric Co., Ltd.) under the conditions of an output of 0.3 kW and a processing speed of 3 m / min. The composition for forming the photo-alignment film was coated on the surface subjected to the corona treatment using a bar coater, dried at 80°C for 1 minute, and subjected to polarized UV exposure using a polarized UV irradiation apparatus (SPOT CURE SP-7 with a polarizer unit; manufactured by Ushio Inc.) with an integrated light quantity of 100 mJ / cm 2 to form a photo-alignment film. When the thickness of the obtained photo-alignment film was measured with an ellipsometer M-220 (manufactured by JASCO Corporation), it was 100 nm.

[0164] According to the following method, the moisture permeability and total light transmittance of the above-mentioned triacetyl cellulose film (KC4CZ-TAC) used as the base film of the retardation film were measured. (Measurement of moisture permeability) The moisture permeability [g / (m2·24hr)] of the protective film at a temperature of 40°C and a relative humidity of 90% was measured by the cup method specified in JIS Z 0208. The moisture permeability of the above TAC film was 370 g / m 2 / 24 hours.

[0165] (Measurement of total light transmittance) In accordance with JIS K7361, the total light transmittance was measured using a haze meter HM150 manufactured by Murakami Color Research Laboratory Co., Ltd. The total light transmittance of the above TAC film was 93%.

[0166] Also, when the retardation values [Re(550) and Rth(550)] at a wavelength of 550 nm of the above TAC film as the base material were measured, they were approximately 0.

[0167] Subsequently, the polymerizable liquid crystal composition (A1) containing the previously prepared polymerizable liquid crystal compound was applied onto the photo-aligned film using a bar coater and dried at 120°C for 1 minute. Then, using a high-pressure mercury lamp (Unicure VB-15201BY-A; manufactured by Ushio Inc.), ultraviolet rays were irradiated from the side where the polymerizable liquid crystal composition (A1) was applied (under a nitrogen atmosphere, integrated light quantity at a wavelength of 313 nm: 500 mJ / cm 2 ) to form a retardation film which is a laminate composed of a triacetyl cellulose film (substrate film) / photo-aligned film / liquid crystal cured film. When the thickness of the obtained liquid crystal cured film was measured with a laser microscope (LEXT; manufactured by Olympus Corporation), it was 2.3 μm.

[0168] When the retardation value of the obtained retardation film at a wavelength of 550 nm was measured, Re(550) = 140 nm. Also, when the retardation values of the obtained retardation film at wavelengths of 450 nm and 650 nm were measured, Re(450) / Re(550) = 0.85 and Re(650) / Re(550) = 1.05.

[0169] (4) Preparation of a polarizer (iodine PVA type polarizer) A polyvinyl alcohol film with a thickness of 30 μm (PVA: average degree of polymerization of about 2400, saponification degree of 99.9 mol% or more) was uniaxially stretched about 5 times by dry stretching, and then immersed in pure water at 40°C for 40 seconds while maintaining the tension state. Then, it was immersed in a dyeing aqueous solution with a mass ratio of iodine / potassium iodide / water of 0.044 / 5.7 / 100 at 28°C for 30 seconds for dyeing treatment. Next, it was immersed in a boric acid aqueous solution with a mass ratio of potassium iodide / boric acid / water of 11.0 / 6.2 / 100 at 70°C for 120 seconds. Subsequently, after washing with pure water at 8°C for 15 seconds, it was dried at 60°C for 50 seconds and then at 75°C for 20 seconds while being held under a tension of 300 N to obtain a polarizer with a thickness of 12 μm in which iodine was adsorbed and oriented on the polyvinyl alcohol film.

[0170] (5) Preparation of an optical laminate The retardation film, polarizer, and triacetyl cellulose film (TAC: "KC4UY" manufactured by Konica Minolta Opto, Inc.) as the transparent protective film prepared above were laminated in this order. An aqueous dry-curing type adhesive was injected so that the triacetyl cellulose side of the retardation film and the polarizer were in contact, and the triacetyl cellulose of the transparent protective film was in contact with the side of the polarizer opposite to the retardation film. The laminate was bonded with a nip roll so that the absorption axis of the polarizer and the slow axis of the liquid crystal cured film in the retardation film were at 45°. While maintaining the tension of the obtained laminate at 430 N / m, it was dried at 60°C for 2 minutes to obtain an optical laminate I (elliptical polarizing plate) composed of a liquid crystal cured film / photo-aligned film / base film / adhesive layer / polarizer / adhesive layer / transparent protective film. The above aqueous dry-curing type adhesive was prepared by adding 3 parts of carboxyl group-modified polyvinyl alcohol (Kuraray Poval KL318; manufactured by Kuraray Co., Ltd.) and 1.5 parts of water-soluble polyamide epoxy resin (Sumirez Resin 650; manufactured by Sumika Chemtex Corporation, aqueous solution with a solid content concentration of 30%) to 100 parts of water.

[0171] When the moisture permeability and total light transmittance of the transparent protective film were measured in the same manner as the measurement method for the base film described above, the moisture permeability was 350 g / m 2 / 24 hours, and the total light transmittance was 93%.

[0172] Also, the 380 nm transmittance of the transparent protective film was measured by the double beam method using an apparatus in which a folder with a polarizer was set in a spectrophotometer (UV-3150 manufactured by Shimadzu Corporation). A mesh that cuts the light amount by 50% was installed on the reference side of the folder. The 380 nm transmittance of the transparent protective film was 8%.

[0173] (6) Evaluation of the optical laminate (i) Evaluation of flexibility The evaluation of flexibility was carried out as follows using the method of "General test method for paints - Flexural resistance (cylindrical mandrel method)" described in JIS-K-5600-5-1. The optical laminate was cut into a 25 mm × 200 mm square, and using a cylindrical mandrel method flex resistance tester Type II (manufactured by TP Giken Co., Ltd.), under the conditions of a temperature of 25°C and a relative humidity of 55% RH, it was wound around a mandrel bar with a diameter of 6 mm (bending radius R = 3 mm) with the liquid crystal cured layer of the retardation film facing outward to conduct a flex resistance test. After the test, using the optical laminate, visual confirmation was carried out with transmitted illumination light in a dark room environment, and when observing the occurrence status of cracks, those with visible cracks were marked as "×", and those without visible cracks were judged as "○". The results are shown in Table 1.

[0174] (ii) Evaluation of oblique reflectance The oblique reflectance of the optical laminate was measured as follows. The side derived from the retardation film of the optical laminate (in the case of Optical Laminate I, the liquid crystal cured film) and a reflector (mirror aluminum plate) were bonded using an acrylic adhesive to prepare a measurement sample. Using a spectrophotometer (CM3700A manufactured by Konica Minolta, Inc.), light from a D65 light source was incident on the measurement sample from an 8° direction to measure the oblique reflectance (reflected Y value). If the oblique reflectance was 1% or more and less than 6%, it was marked as "○", if it was 6% or more and less than 8%, it was marked as "△", and if it was 8% or more, it was marked as "×". The results are shown in Table 1.

[0175] (iii) Evaluation of heat resistance test The side derived from the retardation film of the optical laminate and a glass plate were bonded using an acrylic adhesive to prepare a measurement sample. The obtained measurement sample was placed in an oven at 85°C, and after 500 hours had passed, the in-plane retardation value was measured, and the change amount of the in-plane retardation value at 550 nm before and after the heat resistance test was measured using KOBRA-WR manufactured by Oji Scientific Instruments Co., Ltd. If the change amount was 1 nm or more and less than 3 nm, it was marked as "○", if it was 3 nm or more and less than 5 nm, it was marked as "△", and if it was 5 nm or more, it was marked as "×". The results are shown in Table 1.

[0176] [Example 2] When laminating the retardation film and the polarizer, an optical laminate composed of a substrate film / photo-alignment film / liquid crystal cured film / adhesive layer / polarizer / adhesive layer / transparent protective film was produced and evaluated in the same manner as in Example 1, except that the liquid crystal cured film side was laminated with the polarizer. The results are shown in Table 1.

[0177] [Example 3] An optical laminate composed of a substrate film / photo-alignment film / liquid crystal cured film / adhesive layer / polarizer / adhesive layer / transparent protective film was produced and evaluated in the same manner as in Example 1, except that a polymethyl methacrylate resin film (manufactured by Sumitomo Chemical Co., Ltd., moisture permeability: 50 g / m 2 / 24 h, total light transmittance: 93%, 380 nm transmittance: 6%) was used as the transparent protective film. The results are shown in Table 1.

[0178] [Example 4] An optical laminate composed of a substrate film / photo-alignment film / liquid crystal cured film / adhesive layer / polarizer / adhesive layer / transparent protective film was produced and evaluated in the same manner as in Example 1, except that a cycloolefin polymer film (COP; ZF-14; manufactured by Nippon Zeon Co., Ltd., moisture permeability: 13 g / m 2 / 24 h, total light transmittance: 92%, 380 nm transmittance: 8%) containing an ultraviolet absorber was used as the transparent protective film. The results are shown in Table 1.

[0179] [Comparative Example 1] Using the TAC film used as the transparent protective film in Example 1 as the substrate film, after laminating the transparent protective film and the polarizer with the same aqueous dry-curing type adhesive as used in Example 1 in the production process of the optical laminate, an acrylic adhesive with a cured thickness of 5 μm was used to laminate the side of the polarizer where the transparent protective film was not laminated and the liquid crystal cured film side of the retardation film. An optical laminate composed of a photo-alignment film / liquid crystal cured film / adhesive layer / polarizer / adhesive layer / transparent protective film was produced and evaluated in the same manner as in Example 1, except that the triacetyl cellulose film as the substrate film was peeled off. The results are shown in Table 1.

[0180] [Comparative Example 2] An optical laminate composed of a base film / photo-alignment film / liquid crystal cured film / adhesive layer / polarizer / adhesive layer / transparent protective film was produced and evaluated in the same manner as in Comparative Example 1, except that the triacetyl cellulose which is the base film was not peeled off. The results are shown in Table 1.

[0181] 〔Reference Example 1〕 An optical laminate composed of a base film / photo-alignment film / liquid crystal cured film / adhesive layer / polarizer / adhesive layer / transparent protective film was produced and evaluated in the same manner as in Example 4, except that a cycloolefin polymer film (COP; ZF-14; manufactured by Nippon Zeon Co., Ltd., moisture permeability: 13 g / m 2 / 24 hours, total light transmittance: 92%, transmittance at 380 nm: 90%) was used. The results are shown in Table 1.

[0182]

Table 1

[0183] It was confirmed that the optical laminates (Examples 1 to 4) having the layer configuration according to the present invention are excellent in flexibility and have a low oblique reflectance.

Explanation of Signs

[0184] 1: Retardation film 2: Adhesive layer 3: Polarizer 4: Adhesive layer 5: Transparent protective film 11: Base film 12: Alignment film 13: Liquid crystal cured film 100: Optical laminate

Claims

1. An optical laminate comprising an adhesive layer, a retardation film, a polarizer, and a transparent protective film in this order, wherein: The retardation film has a base film having a moisture permeability of 100 g / m ２ / 24 hours or more, and is formed on the base film and has a thickness of 0.5 μm or more and 3 μm or less, and the following formulas (1) and (2): Re(450) / Re(550) ≤ 1.00 (1) 1.00 ≤ Re(650) / Re(550) (2) 〔wherein, Re(λ) represents the in-plane retardation value at wavelength λ〕 It includes a liquid crystal cured film that satisfies the above with a single layer, and the polarizer is composed of a polyvinyl alcohol-based resin film containing a dichroic dye, the transparent protective film has a total light transmittance of 90% or more and a 380 nm transmittance of 30% or less, the retardation film, the polarizer, and the transparent protective film are adjacent to each other through an adhesive layer having a thickness of 5 μm or less and formed from a dry-curing type adhesive containing polyvinyl alcohol. The retardation film is an optical laminate that is in contact with the adhesive layer that bonds the retardation film and the polarizer on the side of the liquid crystal cured film.

2. The optical laminate according to claim 1, wherein the base film has a total light transmittance of 90% or more and the absolute value of the retardation value Rth(550) in the thickness direction with respect to light at 550 nm is 5 nm or less.

3. The optical laminate according to claim 1 or 2, wherein the retardation film has an optical alignment film with a thickness of 10 nm or more and 1000 nm or less between the base film and the liquid crystal cured film.

4. The optical laminate according to any one of claims 1 to 3, wherein the liquid crystal cured film is a film obtained by curing at least one compound having at least one maximum absorption between wavelengths of 300 to 400 nm.

5. The liquid crystal cured film satisfies the following formula (3): 100 nm ≤ Re(550) ≤ 170 nm (3) 〔wherein, Re(λ) represents the in-plane retardation value at wavelength λ〕 The optical laminate according to any one of claims 1 to 4.

6. The transparent protective film has a water vapor transmission rate of 100 g / m ２ 24 hours or more, and the optical laminate according to any one of claims 1 to 5.

7. An optical laminate roll formed by winding the optical laminate according to any one of claims 1 to 6.

8. An elliptical polarizing plate including the optical laminate according to any one of claims 1 to 6.

9. An organic EL display device including the elliptical polarizing plate according to claim 8.

10. A flexible image display device including the elliptical polarizing plate according to claim 8.

11. The flexible image display device according to claim 10, further including a window and a touch sensor.

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