JP2020024357A - Optical film - Google Patents

Abstract

To provide an optical film with having excellent film strength.SOLUTION: Disclosed is an optical film which includes an optically anisotropic layer consisting of a polymer obtained by polymerizing a polymerizable liquid crystal compound having one or more polymerizable functional groups in an oriented state. The number of alignment defects satisfies 0≤the number of alignment defects (pieces)≤14 in the actual size of the optically anisotropic layer per 1 mmwhich is 0.3 μm or more and 50 μm or less.SELECTED DRAWING: None

Description

  The present invention relates to an optical film, and also relates to a retardation laminate and a polarizing plate.

  As an optical film used for a flat panel display device, for example, an optical film having an optically anisotropic layer obtained by applying a coating solution obtained by dissolving a polymerizable liquid crystal compound in a solvent to a support substrate, and then polymerizing the coating solution. A film has been proposed (Patent Document 1).

JP 2011-207765 A

  In recent years, as the thickness of optical films has been reduced, improvements in film strength and workability of optically anisotropic layers have been demanded.

  An object of the present invention is to provide an optical film having improved film strength. Another object of the present invention is to provide an optical film having improved workability when processed into a polarizing plate.

[式中、欠陥合計面積は、光学顕微鏡の一視野において観察される実サイズが０．３μｍ以上５０μｍ以下の配向欠陥の面積の合計であり、顕微鏡観察視野は、光学顕微鏡の一視野全体に光学異方性層を存在させたときの光学異方性層の面積である]
０≦欠陥率［ｐｐｍ］≦１０００ （３）
［３］ １つ以上の重合性官能基を有する重合性液晶化合物が配向した状態で重合した重合体からなる光学異方性層を有する光学フィルムであって、
前記光学異方性層の１ｍｍ^２当たりにおける実サイズが０．３μｍ以上５０μｍ以下である配向欠陥の個数が下記式（１）を満たし、下記式（２）で定義される欠陥率が下記式（３）を満たすことを特徴とする、光学フィルム。
０≦配向欠陥の個数［個］≦１４ （１）

[式中、欠陥合計面積は、光学顕微鏡の一視野において観察される実サイズが０．３μｍ以上５０μｍ以下の配向欠陥の面積の合計であり、顕微鏡観察視野は、光学顕微鏡の一視野全体に光学異方性層を存在させたときの光学異方性層の面積である]
０≦欠陥率［ｐｐｍ］≦１０００ （３）
［４］ 前記重合性官能基はアクリロイルオキシ基である、［１］〜［３］のいずれかに記載の光学フィルム。
［５］ 前記配向欠陥は、重合性液晶化合物の微結晶に起因する欠陥を含む、［１］〜［４］のいずれかに記載の光学フィルム。
［６］ 光学異方性層の厚みは、０．０５μｍ以上１０μｍ以下である、［１］〜［５］のいずれかに記載の光学フィルム。
［７］ ［１］〜［６］のいずれかに記載の光学フィルムを１以上含む位相差積層体。
［８］ ［７］に記載の位相差積層体を含む偏光板。
［９］ 切断面を有する、［８］に記載の偏光板。
［１０］ 異形偏光板である、［８］又は［９］に記載の偏光板。
［１１］ 前面板またはタッチセンサの少なくとも一方を備える、［８］〜［１０］のいずれかに記載の偏光板。
［１２］ ［８］〜［１１］のいずれかに記載の偏光板を備えるフレキシブル画像表示装置。 The present invention provides the following aspects [1] to [12].
[1] An optical film having an optically anisotropic layer made of a polymer obtained by polymerizing a polymerizable liquid crystal compound having one or more polymerizable functional groups in an oriented state,
An optical film, wherein the number of alignment defects whose actual size per 1 mm ^{2 of the} optically anisotropic layer is 0.3 μm or more and 50 μm or less satisfies the following expression (1).
0 ≦ number of alignment defects [pieces] ≦ 14 (1)
[2] An optical film having an optically anisotropic layer comprising a polymer obtained by polymerizing a polymerizable liquid crystal compound having one or more polymerizable functional groups in an oriented state,
An optical film, wherein the defect rate defined by the following formula (2) in the optically anisotropic layer satisfies the following formula (3).

[In the formula, the total defect area is the total area of the alignment defects having an actual size of 0.3 μm or more and 50 μm or less observed in one visual field of the optical microscope. This is the area of the optically anisotropic layer when the anisotropic layer is present]
0 ≦ defect rate [ppm] ≦ 1000 (3)
[3] An optical film having an optically anisotropic layer composed of a polymer obtained by polymerizing the polymerizable liquid crystal compound having one or more polymerizable functional groups in an oriented state,
The number of alignment defects whose actual size per 1 mm ^{2 of the} optically anisotropic layer is 0.3 μm or more and 50 μm or less satisfies the following expression (1), and the defect rate defined by the following expression (2) is An optical film characterized by satisfying 3).
0 ≦ number of alignment defects [pieces] ≦ 14 (1)

[In the formula, the total defect area is the total area of the alignment defects having an actual size of 0.3 μm or more and 50 μm or less observed in one visual field of the optical microscope. This is the area of the optically anisotropic layer when the anisotropic layer is present]
0 ≦ defect rate [ppm] ≦ 1000 (3)
[4] The optical film according to any one of [1] to [3], wherein the polymerizable functional group is an acryloyloxy group.
[5] The optical film according to any one of [1] to [4], wherein the alignment defect includes a defect caused by microcrystals of a polymerizable liquid crystal compound.
[6] The optical film according to any one of [1] to [5], wherein the thickness of the optically anisotropic layer is 0.05 μm or more and 10 μm or less.
[7] A retardation laminate comprising at least one optical film according to any one of [1] to [6].
[8] A polarizing plate comprising the retardation laminate according to [7].
[9] The polarizing plate according to [8], having a cut surface.
[10] The polarizing plate according to [8] or [9], which is a modified polarizing plate.
[11] The polarizing plate according to any one of [8] to [10], including at least one of a front plate and a touch sensor.
[12] A flexible image display device comprising the polarizing plate according to any one of [8] to [11].

  According to the present invention, an optical film having improved film strength can be provided. Further, according to the present invention, an optical film having improved workability can be provided.

1 is a schematic cross-sectional view illustrating an optical film according to one embodiment of the present invention. FIG. 1 is a schematic cross-sectional view illustrating a retardation stack according to one embodiment of the present invention. FIG. 2 is a schematic cross-sectional view illustrating a polarizing plate according to one embodiment of the present invention. 1 is a schematic cross-sectional view illustrating a flexible image display device according to one embodiment of the present invention.

[Optical film]
An optical film according to one embodiment of the present invention is an optical film formed of a polymer in which a polymerizable liquid crystal compound having one or more polymerizable functional groups (hereinafter, also simply referred to as “polymerizable liquid crystal compound”) is polymerized. The number of alignment defects (hereinafter, also referred to as specific defects) having an anisotropic layer and having an actual size of 0.3 μm or more and 50 μm or less per 1 mm ^{2 of the} optically anisotropic layer satisfies the following formula (1).
0 ≦ number of alignment defects [pieces] ≦ 14 (1)

  The polymer polymerized in a state in which the polymerizable liquid crystal compound contained in the optically anisotropic layer is oriented is preferably one polymerized in a state in which it is oriented in one direction. The orientation may be a horizontal orientation in which the optical axis of the polymerizable liquid crystal compound is oriented horizontally with respect to the optical film plane, or a vertical orientation in which the optical axis of the polymerizable liquid crystal compound is oriented perpendicular to the optical film plane. May be. The optical axis means a direction in which, in a refractive index ellipsoid formed by the orientation of the polymerizable liquid crystal compound, a cross section cut in a direction perpendicular to the optical axis becomes a circle, that is, a direction in which the refractive indices of the two directions are equal. .

  The optically anisotropic layer can exhibit in-plane retardation by polymerizing in a state where the polymerizable liquid crystal compound is oriented in a suitable direction. When the polymerizable liquid crystal compound is rod-shaped, an in-plane retardation is developed by orienting the optical axis of the polymerizable liquid crystal compound horizontally with respect to the optical film plane. In this case, the optical axis direction and the slow axis direction are used. Matches. When the polymerizable liquid crystal compound is disc-shaped, an in-plane retardation is developed by orienting the optical axis of the polymerizable liquid crystal compound horizontally with respect to the optical film plane, and in this case, the optical axis and the slow axis Are orthogonal. The alignment state of the polymerizable liquid crystal compound can be adjusted by, for example, a combination of an alignment film and a polymerizable liquid crystal compound described below.

  Examples of the polymerizable liquid crystal compound include a rod-shaped polymerizable liquid crystal compound and a disc-shaped polymerizable liquid crystal compound. When the rod-shaped polymerizable liquid crystal compound is horizontally or vertically aligned with respect to the optical film plane, the optical axis of the polymerizable liquid crystal compound coincides with the major axis direction of the polymerizable liquid crystal compound. When the discotic polymerizable liquid crystal compound is oriented, the optical axis of the polymerizable liquid crystal compound exists in a direction orthogonal to the disc surface of the polymerizable liquid crystal compound.

  The polymerizable liquid crystal compound is a compound having one or more polymerizable functional groups and having liquid crystallinity. The polymerizable functional group means a group participating in a polymerization reaction, and is preferably a photopolymerizable group. Here, the photopolymerizable group refers to a group that can participate in a polymerization reaction by an active radical, an acid, or the like generated from a photopolymerization initiator described below. Examples of the polymerizable functional group 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 vinyloxy group, an oxiranyl group and an oxetanyl group are preferable, and an acryloyloxy group is more preferable. The liquid crystal property of the polymerizable liquid crystal compound may be a thermotropic liquid crystal or a lyotropic liquid crystal. If the thermotropic liquid crystal is classified according to the degree of order, it may be a nematic liquid crystal or a smectic liquid crystal. The polymerizable liquid crystal compound preferably has two or more polymerizable functional groups, and more preferably has two polymerizable functional groups.

  The polymerizable liquid crystal compound preferably has a molecular weight of 250 or more for one polymerizable functional group. For example, when the polymerizable liquid crystal compound has two polymerizable functional groups, the molecular weight of the polymerizable liquid crystal compound may be 500 or more. When the polymerizable liquid crystal compound has a molecular weight of 250 or more for one polymerizable functional group, good liquid crystallinity tends to be easily obtained. The polymerizable liquid crystal compound has a molecular weight for one polymerizable functional group of preferably 280 or more, more preferably 300 or more, and usually 1,000 or less.

  The molecular weight of the polymerizable liquid crystal compound is preferably 500 or more, more preferably 560 or more, further preferably 600 or more, and usually 2,000 or less. The polymerizable liquid crystal compound tends to be less likely to be crystallized as the molecular weight is smaller. Therefore, from the viewpoint of reducing specific defects caused by microcrystals, a polymerizable liquid crystal compound having a small molecular weight is preferably used. On the other hand, the larger the molecular weight of the polymerizable liquid crystal compound, the easier it is to crystallize, and the number of alignment defects due to crystallization tends to increase. When a polymerizable liquid crystal compound having a relatively large molecular weight, for example, 500 or more is used, in order to keep the number of specific defects within the range specified in the present invention, for example, two or more liquid crystal compounds are used as the polymerizable liquid crystal compound. Polymerization can be carried out in combination to form a polymer, or the humidity at the time of applying the polymerizable liquid crystal compound onto a substrate can be relatively low.

  As the rod-shaped polymerizable liquid crystal compound and the disc-shaped polymerizable liquid crystal compound, known compounds can be used. For example, a liquid crystal handbook (edited by a liquid crystal handbook editing committee, published by Maruzen Co., Ltd. on October 30, 2000) Compounds having a polymerizable group among the compounds described in “3.8.6 Network (completely crosslinked type)” and “6.5.1 Liquid crystal material b. Polymerizable nematic liquid crystal material” -207765, JP-A-2010-24438, JP-A-2015-163937, JP-A-2017-179267, JP-A-2016-42185, WO2016 / 158940, JP-A-2016-224128 Compounds exemplified in Japanese Patent Application Laid-Open Publication No. H10-15064 can be used. The optically anisotropic layer may contain only one polymer of the polymerizable liquid crystal compound, or may contain two or more polymers.

  In recent years, a thinner optical film has been demanded, and a thinner optically anisotropic layer containing a polymer of a polymerizable liquid crystal compound has been demanded. However, an optically anisotropic layer having a small thickness and in which a polymer of a polymerizable liquid crystal compound is oriented in one direction is very liable to be broken, and the film strength tends to be low. The present inventor has studied on improving the film strength of the optical film. As a result, the optically anisotropic layer made of a polymer obtained by polymerizing the polymerizable liquid crystal compound in an oriented state has a film strength, processability, and optical anisotropy. It has been found that there is a correlation between the number of alignment defects in the layer. The present inventor who paid attention to that fact further researched, and found that the smaller the number of the above specific defects in the optically anisotropic layer, the more the film strength of the optical film tends to be excellent, and the number of the specific defects is above It was ascertained that the film strength and workability of the optically anisotropic layer tended to be improved when the formula (1) was satisfied. Naturally, it is ideal and desirable that the optical film has zero specific defects, but it is difficult to produce an optically anisotropic layer having zero specific defects. Therefore, the optical film usually has a specific defect, and when the optical film having the specific defect is used or processed, the stress generated in the optical film is concentrated on the specific defect, and the optical film is broken or torn. It is estimated that For this reason, when the number of specific defects present in the optically anisotropic layer made of an oriented polymer of a polymerizable liquid crystal compound having a specific molecular weight is small, the portion where stress is concentrated is reduced, and as a result, the optical film is It is considered that the film is less likely to be cracked or torn, and the workability of the optical film is improved.

  The specific defect is a region where poor alignment of the polymerizable liquid crystal compound has occurred, and is observed as a bright spot under an optical microscope crossed Nicol state. The specific defects include microcrystals and gels of the polymerizable liquid crystal compound, foreign matter, repelling and irregularities of the coating film of the polymerizable liquid crystal compound, defects in the alignment film, irregularities and scratches on the substrate, defects caused by substrate contamination, and the like. Good.

The specific size of the specific defect is 0.3 μm or more and 50 μm or less. The actual size refers to a value obtained by measuring the length of a portion where the dimension is maximized with respect to the external shape of a defect visually observed when the bright spot is observed by releasing the crossed Nicol state of the optical microscope. For example, when the outline of the defect is visually recognized as a circle, the actual size is the length of the diameter of the circle. For example, when the outline of the defect is visually recognized as a rectangle, the actual size is the length of the diagonal of the rectangle. When the actual size of the defect is less than 0.3 μm, it tends to be hard to be observed as a bright spot under an optical microscope crossed Nicols state. If the actual size of the defect is more than 50 μm, the optical film tends to be visually recognized easily and the optical film tends to be unusable due to poor appearance. Defects having an actual size of 0.3 μm or more and 50 μm or less are not recognized as bright spots because the polarization degree of the polarizing plate is lower than the current state and tends to be hardly observed as bright spots under the cross microscope condition of an optical microscope. It is a thing. However, in recent years, reduction of such defects has been demanded from the viewpoint of further improving quality. The number of defects having an actual size of more than 50 μm is ideally and desirably 0 / mm ² , but exists as long as the number does not affect the appearance, film strength, and workability of the optical film. Usually, it is usually 3 / mm ² or less, and at most 5 / mm ² or 6 / mm ² . Defects whose actual size exceeds 50 μm are mostly caused by foreign substances.

  The actual size may be, for example, 0.5 μm or more, or 1 μm or more, or 5 μm or more. On the other hand, the actual size may be, for example, 40 μm or less, or 30 μm or less, or 20 μm or less.

  In order that the number of specific defects satisfies the formula (1), for example, adjustment of the composition of a liquid crystal composition described later, which constitutes the optically anisotropic layer, adjustment of manufacturing conditions, or a combination thereof can be performed. .

  When the composition of the liquid crystal composition is adjusted, for example, the ratio of the polymerizable liquid crystal compound, the ratio of the hardly soluble polymerizable liquid crystal compound, the solid concentration, and the like in the liquid crystal composition can be adjusted.

  The liquid crystal composition can preferably contain two or more polymerizable liquid crystal compounds from the viewpoint of reducing specific defects caused by microcrystals in the optically anisotropic layer. When the liquid crystal composition contains two or more polymerizable liquid crystal compounds, if the mass ratio of the main polymerizable liquid crystal compound is high, crystals of the polymerizable liquid crystal compound tend to precipitate. Therefore, when the mass ratio of the main polymerizable liquid crystal compound in the liquid crystal composition is reduced, the number of specific defects due to microcrystals tends to decrease. When the liquid crystal composition contains two or more polymerizable liquid crystal compounds, the main polymerizable liquid crystal compound in the liquid crystal composition may be, for example, 90% by mass or less, preferably 85% by mass, based on the total amount of the polymerizable liquid crystal compound. % By mass or less. The microcrystal refers to a crystal having a size of several nm to several hundred μm, a crystal grain, and an aggregate thereof.

  As described above, the larger the molecular weight of the polymerizable liquid crystal compound, the easier it is to crystallize, and the number of specific defects due to microcrystals tends to increase. For this reason, when using a polymerizable liquid crystal compound having a relatively large molecular weight, for example, a polymerizable liquid crystal compound having a molecular weight of 500 or more, for example, in order to keep the number of alignment defects within the range specified in the present invention, Polymerization can be carried out by combining two or more liquid crystal compounds as compounds.

  When the liquid crystal composition contains a hardly soluble polymerizable liquid crystal compound, crystals of the hardly soluble polymerizable liquid crystal compound tend to precipitate. Therefore, when the mass ratio of the hardly soluble liquid crystal composition is decreased or the mass ratio of the easily soluble polymerizable liquid crystal compound is increased, the number of specific defects due to microcrystals tends to decrease. When the liquid crystal composition contains a hardly soluble polymerizable liquid crystal compound, the hardly soluble polymerizable liquid crystal compound in the liquid crystal composition may be, for example, 90% by mass or less, preferably 85% by mass, based on the total amount of the polymerizable liquid crystal compound. % Or less.

  When the amount of the solvent is increased and the solid content is reduced in the liquid crystal composition, the crystal of the polymerizable liquid crystal compound becomes difficult to precipitate, and the number of specific defects due to microcrystals tends to decrease. Also, when the amount of the solvent is increased and the solid content is lowered, the solvent in the coating film is difficult to completely volatilize, so that the crystal of the polymerizable liquid crystal compound is difficult to precipitate, and the number of specific defects caused by microcrystals is reduced. Tends to decrease. The solid content of the liquid crystal composition may be, for example, 50% by mass or less, and preferably 25% by mass or less.

  A monomer other than the polymerizable liquid crystal compound (for example, a low-molecular monomer such as acrylate or methacrylate) or a polymer (for example, a polymer such as polyvinyl alcohol or polyethylene glycol and a modified product thereof) other than the polymerizable liquid crystal compound, or the polymerizable liquid crystal compound When a part or all of the compound is converted into a dimer, a trimer, or a higher oligomer before orientation and polymerization, the number of specific defects due to microcrystals tends to decrease. When the liquid crystal composition contains a monomer or polymer other than the polymerizable liquid crystal compound, or a dimer, trimer or higher oligomer of the polymerizable liquid crystal compound, solubility in a solvent is improved, and precipitation of crystals is suppressed. Tend to be easier.

  When adjusting the production conditions, for example, the temperature of the substrate when applying the liquid crystal composition, the humidity of the surrounding atmosphere during coating, the surrounding atmosphere of the die used for coating, and the like can be adjusted.

  The base material on which the liquid crystal composition is applied tends to reduce the number of specific defects caused by microcrystals by keeping the temperature at a constant temperature when applying the liquid crystal composition. The temperature for keeping the temperature may be, for example, 15 ° C or more and 60 ° C or less, and preferably 20 ° C or more and 50 ° C or less.

  By using a substrate having good surface smoothness, the uniformity of the coating of the polymerizable liquid crystal compound is increased, and the number of specific defects due to repelling of the coating of the polymerizable liquid crystal compound and poor alignment film tend to decrease. . Means for improving the smoothness of the surface of the base material include, for example, annealing (orientation). Annealing can be performed by heating the substrate, and the heating temperature may be, for example, 60 ° C. or more and 100 ° C. or less, or a temperature 5 ° C. to 20 ° C. lower than the glass transition point of the substrate. The time for performing may be, for example, 1 second or more and 60 seconds or less.

  By making the humidity of the surrounding atmosphere constant during coating, crystallization of the polymerizable liquid crystal compound is easily suppressed, and the number of specific defects due to microcrystals tends to be reduced. The humidity of the surrounding atmosphere at the time of coating may be, for example, 90% RH or less, preferably 85% RH or less, more preferably 60% RH or less, further preferably 55% RH or less, and particularly preferably. Is 40% RH or less. On the other hand, the humidity of the surrounding atmosphere at the time of coating may be, for example, 10% RH or more, and preferably 20% RH or more. When using a polymerizable liquid crystal compound having a relatively large molecular weight, the humidity at the time of coating the polymerizable liquid crystal compound on a substrate may be relatively low so that the number of specific defects is within the range specified in the present invention. it can.

  By adjusting the atmosphere around the die used for coating to the vapor pressure of the solvent contained in the polymerizable liquid crystal compound (under the solvent atmosphere), the solvent of the polymerizable liquid crystal compound is less likely to volatilize, and the crystal of the polymerizable liquid crystal compound is crystallized. And the number of specific defects due to microcrystals tends to decrease.

  By removing contamination on the surface of the base material, for example, PET lubricant, PET oligomer, silicone oil, etc., before applying the liquid crystal composition, the number of specific defects due to foreign matter tends to be reduced. In addition, when the liquid crystal composition is applied in a clean room having a high degree of cleanliness, the number of specific defects due to foreign matter tends to decrease. In addition, by removing foreign substances, microcrystals, and the like in the liquid crystal composition before coating with a filter, the number of specific defects due to microcrystals and foreign substances tends to be reduced.

The number of specific defects per 1 mm ^{2 of the} optically anisotropic layer is preferably 10 or less, more preferably 7 or less, still more preferably 6 or less, particularly preferably 3 or less, particularly preferably 1 or less. is there. The number of specific defects per 1 mm ^{2 of the} optically anisotropic layer is ideally 0, but may be 0.001 or more, and may be 0.01 or more. .

The ratio of the number of defects caused by microcrystals to the number of specific defects per 1 mm ^{2 of the} optically anisotropic layer may be, for example, 70% or more, or 85% or more, and preferably 90% or more. It is. In the case of microcrystals, if microcrystals are present in the optically anisotropic layer, it is presumed that when stress is applied, the crystal portion becomes a stress concentration point and is broken. Therefore, when 70% or more of the specific defects are caused by the microcrystals, the number of the specific defects caused by the microcrystals becomes 14 or less, and the stress is moderately dispersed in the thickness of the optically anisotropic layer of the present invention. It is estimated that the film strength increases.

The ratio of the number of defects caused by foreign matter to the number of specific defects per 1 mm ^{2 of the} optically anisotropic layer may be, for example, 10% or less, or 0%.

The ratio of the number of defects caused by repelling to the number of specific defects per 1 mm ^{2 of the} optically anisotropic layer may be, for example, 10% or more and 70% or less, or 20% or more and 60% or less.

  The film strength of the optically anisotropic layer can be evaluated according to a piercing strength measuring method described in the section of Examples described later. The piercing strength of the optical film may be, for example, from 5 gmm to 100 gmm, preferably from 10 gmm to 80 gmm, more preferably from 15 gmm to 50 gmm. When the piercing strength of the optical film is within the above range, good film strength tends to be easily obtained even when the optical film is thinned.

  The film strength of the optically anisotropic layer can be evaluated according to a piercing strength measuring method described in the section of Examples described later. The piercing strength of the optical film may be, for example, 5 g · mm to 100 g · mm, preferably 10 g · mm to 80 g · mm, more preferably 15 g · mm to 50 g · mm. When the piercing strength of the optical film is within the above range, good film strength tends to be easily obtained even when the optical film is thinned.

The film strength of the optically anisotropic layer can also be evaluated according to a tensile stress measuring method described in the section of Examples described later. Tensile stress of the optical film, for example, 30 N / mm ² or more 200 N / mm ² may be less, preferably 40N / mm ² or more 150 N / mm ² or less, more preferably 50 N / mm ² or more 100 N / mm ² or less is there. When the tensile stress of the optical film is within the above range, good film strength tends to be easily obtained even when the optical film is thinned.

  The optical film may further have a substrate layer and an orientation layer in addition to the optically anisotropic layer.

  The base layer can be composed of, for example, a resin film or the like. The resin constituting the resin film is a translucent thermoplastic resin, preferably an optically transparent thermoplastic resin, for example, a polyolefin resin such as polyethylene and polypropylene; a cyclic polyolefin resin such as a norbornene polymer. Polyester resins such as polyethylene terephthalate and polyethylene naphthalate; (meth) acrylic resins such as (meth) acrylic acid and polymethyl (meth) acrylate; triacetyl cellulose, diacetyl cellulose, cellulose acetate propionate and the like. Cellulose ester resins; vinyl alcohol resins such as polyvinyl alcohol and polyvinyl acetate; polycarbonate resins; polystyrene resins; polyarylate resins; polysulfone resins; polyethersulfone resins; Bromide resins; polyimide resins; polyether ketone resins; polyphenylene sulfide resins; polyphenylene oxide resin, and mixtures thereof, may be mentioned copolymer and the like. Among these resins, it is preferable to use any of a cyclic polyolefin-based resin, a polyester-based resin, a cellulose ester-based resin, and a (meth) acrylic acid-based resin, or a mixture thereof.

  The thickness of the base material layer may be, for example, 1 μm or more and 300 μm or less, and is preferably 5 μm or more and 200 μm or less, more preferably 10 μm or more and 120 μm or less from the viewpoint of workability such as strength and handleability.

The heat capacity per 1 cm ^{2 of the} base material layer is not particularly limited, but is preferably 1 cm ^{2 from} the viewpoint that the temperature of the optical film can be easily controlled by an environmental temperature control device such as a drying furnace or a cooling furnace. The heat capacity per ² is 0.1 J / cm ² · ° C. or less, more preferably 0.05 J / cm ² · ° C. or less, and particularly preferably 0.03 J / cm ² · ° C. or less. Here, the heat capacity per 1 cm ² of the base material layer refers to the heat capacity of the volume included when the base material layer is cut out by 1 cm ² .

  Further, the specific heat of the base material layer is not particularly limited, but from the same viewpoint, is preferably 2,000 J / kg · ° C. or less, more preferably 1,500 J / kg · ° C. or less.

  When the optical film has a base layer and an alignment layer, in order to improve the adhesion between the base layer and the alignment layer, the surface of the base layer on which the alignment layer is formed is subjected to corona treatment and plasma treatment. , A flame treatment or the like, and a primer layer or the like may be formed.

  The alignment layer has an alignment controlling force for aligning the polymerizable liquid crystal compound in a desired direction. Examples of the alignment layer include an alignment polymer layer formed of an alignment polymer, a photo alignment polymer layer formed of a photo alignment polymer, and a grub alignment layer having a concavo-convex pattern or a plurality of groves (grooves) on the layer surface. The thickness of the alignment layer can be generally from 10 nm to 4000 nm, and preferably from 50 nm to 3000 nm.

  The oriented polymer layer can be formed by applying a composition obtained by dissolving an oriented polymer in a solvent to a base layer, removing the solvent, and performing a rubbing treatment as necessary. In this case, the alignment regulating force can be arbitrarily adjusted depending on the surface state of the alignment polymer and the rubbing conditions in the alignment polymer layer formed of the alignment polymer.

  The photo-alignable polymer layer is formed by applying a composition containing a polymer or a monomer having a photoreactive group and a solvent (hereinafter, also referred to as a composition for forming a photo-alignment film) to a base layer and irradiating light such as ultraviolet rays. Can be formed. In particular, when an alignment regulating force is exerted in the horizontal direction, it can be formed by irradiating polarized light. In this case, in the photo-alignable polymer layer, the alignment regulating force can be arbitrarily adjusted depending on, for example, the polarized light irradiation conditions for the photo-alignable polymer.

  The grub alignment layer is, for example, exposed through a mask for exposure having a pattern-shaped slit on the surface of the photosensitive polyimide film, a method of forming a concavo-convex pattern by performing development, etc., the plate-shaped master having grooves on the surface, active Forming an uncured layer of energy ray-curable resin, transferring this layer to a substrate layer and curing, forming an uncured layer of active energy ray-curable resin on the substrate layer, It can be formed by, for example, a method of forming unevenness by pressing a roll-shaped master having unevenness and curing the same.

  When the optical film includes a base layer and an alignment layer, when the base layer is separated, the alignment layer may be separated together with the base layer, or the alignment layer remains on the optically anisotropic layer. Is also good. Whether the alignment layer is peeled off together with the base layer or remains in the optically anisotropic layer can be set by adjusting the relationship of the adhesion between the respective layers, and is performed, for example, on the base layer. It can be adjusted by the above-described corona treatment, plasma treatment, flame treatment, surface treatment such as a primer layer, and the components of the liquid crystal composition used for forming the optically anisotropic layer.

[式中、欠陥合計面積は、光学顕微鏡の一視野において観察される実サイズが０．３μｍ以上５０μｍ以下の欠陥の面積の合計であり、顕微鏡観察視野は、前記光学顕微鏡の一視野において観察される光学異方性層の面積である]
０≦欠陥率［ｐｐｍ］≦１０００ （３） An optical film according to another embodiment of the present invention is an optical film having an optically anisotropic layer composed of a polymer obtained by polymerizing a polymerizable liquid crystal compound having one or more polymerizable functional groups in an oriented state. The defect rate defined by the following formula (2) in the optically anisotropic layer satisfies the following formula (3).

[In the formula, the total defect area is the total area of the defects whose actual size observed in one field of the optical microscope is 0.3 μm or more and 50 μm or less, and the microscope observation field is observed in one field of the optical microscope. Is the area of the optically anisotropic layer.]
0 ≦ defect rate [ppm] ≦ 1000 (3)

The microscope observation visual field in Expression (2) may be, for example, 4.53 mm ² . The defect rate can be determined according to a defect rate measuring method described in the section of Examples described later.

  When the defect rate of the optically anisotropic layer satisfies Expression (3), the film strength and workability of the optically anisotropic layer tend to be improved. The defect rate of the optically anisotropic layer is preferably 600 ppm or less, more preferably 300 ppm or less, further preferably 100 ppm or less, particularly preferably 50 ppm or less from the viewpoint of the film strength and workability of the optically anisotropic layer. The defect rate of the optically anisotropic layer is ideally 0 ppm, but may be 0.01 ppm or more, and may be 0.1 ppm or more.

In order to make the defect rate of the optically anisotropic layer satisfy the formula (3), for example, it is necessary to select the type and molecular weight of the polymerizable liquid crystal compound, adjust the composition, adjust the manufacturing conditions, and a combination thereof. it can. Specific examples of the adjustment of the type and molecular weight of the polymerizable liquid crystal compound, the adjustment of the composition, and the adjustment of the production conditions are as follows. The number of defects having an actual size of 0.3 μm or more and 50 μm or less per 1 mm ² of the optically anisotropic layer is described. What is illustrated to satisfy equation (1) applies.

０≦欠陥率［ｐｐｍ］≦１０００ （３）
[式中、欠陥合計面積は、光学顕微鏡の一視野において観察される実サイズが０．３μｍ以上５０μｍ以下の欠陥の面積の合計であり、顕微鏡観察視野は、光学顕微鏡の一視野において観察される光学異方性層の面積である] An optical film according to yet another embodiment of the present invention is an optical film having an optically anisotropic layer containing a polymer obtained by polymerizing a polymerizable liquid crystal compound having one or more polymerizable functional groups in an oriented state. The number of defects having an actual size of 0.3 μm or more and 50 μm or less per 1 mm ^{2 of the} optically anisotropic layer satisfies the following expression (1), and the defect rate defined by the following expression (2) is Meet).
0 ≦ number of alignment defects [pieces] ≦ 14 (1)

0 ≦ defect rate [ppm] ≦ 1000 (3)
[Wherein, the total defect area is the total area of the defects whose actual size observed in one field of the optical microscope is 0.3 μm or more and 50 μm or less, and the microscope observation field is observed in one field of the optical microscope. The area of the optically anisotropic layer]

When the number of defects having an actual size of 0.3 μm or more and 50 μm or less per 1 mm ^{2 of the} optically anisotropic layer satisfies the expression (1) and the defect rate satisfies the expression (3), the film of the optically anisotropic layer It tends to be excellent in strength and workability.

  The optical film is excellent in transparency and has a single layer or a laminated structure (for example, a structure of two or more layers and four layers or less) alone, and can be used for various applications together with a substrate and / or an alignment film or various optical films. it can. When a plurality of layers are laminated, the same film may be used, or different films may be used in combination. Here, the optical film is a film capable of transmitting light and means a film having an optical function, and the optical function means refraction, birefringence, or the like.

Examples of the optical film include a first form: a retardation film in which a rod-like liquid crystal compound is horizontally oriented with respect to a supporting substrate;
Second form: a retardation film in which a rod-shaped liquid crystal compound is oriented in a direction perpendicular to a supporting substrate,
Third form: a retardation film in which the orientation direction of the rod-shaped liquid crystal compound is changed spirally in a plane,
Fourth embodiment: a retardation film in which a discotic liquid crystal compound is obliquely oriented,
Fifth embodiment: a biaxial retardation film in which a discotic liquid crystal compound is oriented in a direction perpendicular to a supporting substrate.

  The optical film may have a retardation value (Re (550 nm)) at a wavelength of 550 nm of, for example, 113 nm or more and 163 nm or less, preferably 130 nm or more and 150 nm or less, more preferably about 135 nm or more and 150 nm or less. When the optical film has a retardation value at a wavelength of 550 nm in the above range, it is suitable for a quarter-wave retardation film.

The optical film preferably has reverse wavelength dispersion. The reverse wavelength dispersibility is an optical property in which the in-plane retardation value of the liquid crystal alignment at a short wavelength is smaller than the in-plane retardation value of the liquid crystal alignment at a long wavelength. i) and equation (ii). Note that Re (λ) represents an in-plane retardation value for light having a wavelength of λ nm.
Re (450) / Re (550) ≦ 1 (i)
1 ≦ Re (630) / Re (550) (ii)
When the optical film has the above-described first form and has reverse wavelength dispersion, coloring during black display on a display device is preferably reduced. In the formula (1), 0.82 ≦ Re (450) / Re ( More preferably, (550) ≦ 0.93. Further, it is preferable that 120 ≦ Re (550) ≦ 150.

When the optical film of the second embodiment described above, the in-plane retardation value Re (550) is in the range of 0 to 10 nm, preferably it may be adjusted in the range of 0 to 5 nm, a thickness retardation value _{R th} May be adjusted in the range of -10 to -300 nm, preferably in the range of -20 to -200 nm.

Retardation value in the thickness direction R _th, which means the refractive index anisotropy in the thickness direction retardation value measured by inclining 50 degrees fast axis in plane as a tilt axis R ₅₀ and the in-plane retardation value It can be calculated from the R _e. That is, the retardation value _Rth in the thickness direction is the in-plane retardation value R _e , the retardation value R ₅₀ measured at an angle of 50 degrees with the fast axis being the inclined axis, the thickness d of the retardation film, and the position. the average refractive index _{n 0} of the retardation film, obtains the n _x, n _y and n _z by the following equation (iv) ~ (vi), and these are substituted into equation (iii), it can be calculated.

_Rth = [( _nx + _ny ) / 2- _nz ] .times.d (iii)
_{R e = (n x -n y} ) × d (iv)
_{R 50 = (n x -n y} ') × d / cos (φ) (v)
_{(n x + n y + n} z) / 3 = n 0 (vi)
here,
φ = sin ^-1 [sin (40 °) / n ₀ ]
_{n y '= n y × n} z / ^{_{[n y 2 × sin 2 (φ}} ) + n z 2 × cos 2 (φ) ] ^1/2

  In order to use the optical film as an optical film for a vertical alignment (VA) mode, the content of the polymerizable liquid crystal compound in the liquid crystal composition may be appropriately adjusted to adjust the thickness of the optical film. Specifically, the film thickness may be adjusted so that Re (550) is, for example, 40 nm or more and 100 nm or less, preferably 60 nm or more and 80 nm or less.

[Production method of optical film]
The optical film can be produced, for example, by preparing a liquid crystal composition, then coating the liquid crystal composition on a substrate or an alignment film, drying, and polymerizing a polymerizable liquid crystal compound.

<Liquid crystal composition>
The liquid crystal composition can be prepared by mixing a polymerizable liquid crystal compound optionally with a solvent, a polymerization initiator, a sensitizer, a polymerization inhibitor, and / or a leveling agent.

  The larger the molecular weight of the polymerizable liquid crystal compound, the easier it is to crystallize and the more specific defects due to microcrystals tend to be.Therefore, when using a polymerizable liquid crystal compound with a relatively large molecular weight, In order to achieve the range specified in the present invention, for example, polymerization can be performed by combining two or more liquid crystal compounds as the polymerizable liquid crystal compound.

(Polymerizable liquid crystal compound)
As the polymerizable liquid crystal compound, for example, JP-A-2011-207765, JP-A-2010-24438, JP-A-2015-163937, JP-A-2017-179267, JP-A-2016-42185, International Publication Those exemplified in JP-A-2016 / 158940 and JP-A-2016-224128 can be used alone or in combination of two or more. The polymerizable liquid crystal compound has one or more polymerizable functional groups, preferably has two or more polymerizable functional groups, more preferably has two or more and four or less polymerizable functional groups, More preferably, it has two polymerizable functional groups.

  The polymerizable liquid crystal compound may have a molecular weight for one polymerizable functional group of, for example, 250 or more. For example, when the polymerizable liquid crystal compound has two polymerizable functional groups, the molecular weight of the polymerizable liquid crystal compound may be 500 or more. When the polymerizable liquid crystal compound has a molecular weight of 250 or more for one polymerizable functional group, good liquid crystallinity tends to be easily obtained. The polymerizable liquid crystal compound has a molecular weight for one polymerizable functional group of preferably 280 or more, more preferably 300 or more, and usually 1,000 or less.

  The molecular weight of the polymerizable liquid crystal compound is preferably 500 or more, more preferably 560 or more, further preferably 600 or more, and usually 2,000 or less.

Examples of the polymerizable liquid crystal compound include compounds satisfying all of the following (1) to (4).
(1) a compound capable of forming a nematic phase;
(2) The polymerizable liquid crystal compound has π electrons on the major axis direction (a).
(3) π electrons are present in a direction (cross direction (b)) intersecting with the long axis direction (a).
(4) A polymerizable liquid crystal compound defined by the following formula (i), where N (πa) is the total of π electrons present in the major axis direction (a), and N (Aa) is the total of molecular weights present in the major axis direction. Π electron density in the major axis direction (a):
D (πa) = N (πa) / N (Aa) (i)
And a polymerizable liquid crystal compound defined by the following formula (ii), where N (πb) is the total of π electrons present in the cross direction (b), and N (Ab) is the total of molecular weights present in the cross direction (b). Electron density in the cross direction (b) of
D (πb) = N (πb) / N (Ab) (ii)
And
0 ≦ [D (πa) / D (πb)] ≦ 1
[That is, the π electron density in the cross direction (b) is larger than the π electron density in the long axis direction (a)].
The polymerizable liquid crystal compound that satisfies all of the above (1) to (4) can form a nematic phase by, for example, applying it on an alignment film and heating it to a phase transition temperature or higher. In a nematic phase formed by aligning the polymerizable liquid crystal compound, the polymerizable liquid crystal compound is usually aligned such that the major axes thereof are parallel to each other, and the major axis is the alignment direction of the nematic phase.

で表される化合物が挙げられる。 In general, the polymerizable liquid crystal compound having the above characteristics generally shows reverse wavelength dispersion. Specific examples of the compound satisfying the above properties (1) to (4) include, for example, the following formula (I):

The compound represented by these is mentioned.

In the formula (I), Ar represents a divalent aromatic group which may have a substituent. The aromatic group referred to here is a group having a planar structure with a cyclic structure, and the cyclic structure has [4n + 2] π electrons according to the Huckel rule. Here, n represents an integer. When a ring structure is formed including a hetero atom such as -N = or -S-, the case where the compound has aromaticity by satisfying the Huckel rule, including a non-covalent bond electron pair on the hetero atom, is also included. The divalent aromatic group preferably contains at least one of a nitrogen atom, an oxygen atom, and a sulfur atom.
G ¹ and G ² each independently represent a divalent aromatic group or a divalent alicyclic hydrocarbon group. Here, a hydrogen atom contained in the divalent aromatic group or the divalent alicyclic hydrocarbon group is a halogen atom, an alkyl group having 1 to 4 carbon atoms, a fluoroalkyl group having 1 to 4 carbon atoms, The carbon atom constituting the divalent aromatic group or the divalent alicyclic hydrocarbon group may be substituted with an alkoxy group, a cyano group or a nitro group of the formulas 1 to 4, and is an oxygen atom, a sulfur atom Alternatively, it may be substituted by a nitrogen atom.
L ¹ , L ² _, B ¹ and B ² are each independently 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 + 1. Here, when 2 ≦ k + 1, 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, wherein a hydrogen atom contained in the alkanediyl group may be substituted with a halogen atom, is, -O - - _-CH 2 contained, - S -, - it may be substituted with Si-.
P ¹ and P ² independently represent a polymerizable functional group or a hydrogen atom, and at least one is a polymerizable functional group.

G ¹ and G ² are each independently preferably a 1,4-phenylenediyl group optionally 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. A 1,4-cyclohexanediyl group optionally 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 1-cyclohexanediyl group substituted with a methyl group , 4-phenylenediyl group, unsubstituted 1,4-phenylenediyl group or unsubstituted 1,4-trans-cyclohexanediyl group, particularly preferably unsubstituted 1,4-phenylenediyl group or unsubstituted 1,4-phenylenediyl group. It is a substituted 1,4-trans-cyclohexanediyl group.
Further, at least one of a plurality of G ¹ and G ² is preferably a divalent alicyclic hydrocarbon group, and at least one of G ¹ and G ² bonded to L ¹ or L ^2. One is more preferably a divalent alicyclic hydrocarbon group.

L ¹ and L ² are preferably each independently 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 to} R ^a8 each independently represent a single bond or an alkylene group having 1 to 4 carbon atoms, and R ^c and R ^d each represent an alkyl group having 1 to 4 carbon atoms or a hydrogen atom. L ¹ and L ² are each independently more preferably a single bond, —OR ^a2-1 —, —CH ₂ —, —CH ₂ CH ₂ —, ^{—COOR a4-1} —, or OCOR ^a6-1 —. . ^{Wherein, R a2-1, R a4-1, R} a6-1 each independently a single _{bond, -CH 2 -, - CH 2} CH 2 - represents either. L ¹ and L ² are each independently more preferably a single bond, —O—, —CH ₂ CH ₂ —, —COO—, —COOCH ₂ CH ₂ —, or OCO—.

B ¹ and B ² are preferably each independently a single bond, an alkylene group having 1 to 4 carbon atoms, —O—, —S—, —R ^a9 OR ^a10 —, —R ^a11 COOR ^a12 —, and —R ^a13. OCOR ^a14 − or R ^a15 OC = OOR ^a16 −. Here, R ^{a9 to} R ^a16 each independently represent a single bond or an alkylene group having 1 to 4 carbon atoms. B ¹ and B ² are each independently preferably a single bond, —OR ^a10-1 —, —CH ₂ —, —CH ₂ CH ₂ —, ^{—COOR a12-1} —, or OCOR ^a14-1 —. . ^{Wherein, R a10-1, R a12-1, R} a14-1 each independently a single _{bond, -CH 2 -, - CH 2} CH 2 - represents either. 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 —. .

  k and l are preferably in the range of 2 ≦ k + 1 ≦ 6, preferably k + 1 = 4, and more preferably k = 2 and l = 2, from the viewpoint of developing reverse wavelength dispersion. It is preferable that k = 2 and l = 2 because a symmetric structure is obtained.

E ¹ and E ² are each independently preferably an alkanediyl group having 1 to 17 carbon atoms, more preferably an alkanediyl group having 4 to 12 carbon atoms.

Examples of the polymerizable functional group represented by P ¹ or P ² 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, and oxiranyl. And oxetanyl groups. Among them, an acryloyloxy group, a methacryloyloxy group, a vinyloxy group, an oxiranyl group and an oxetanyl group are preferable, and an acryloyloxy group is more preferable.

  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, and an anthracene ring, and a benzene ring and a naphthalene ring are preferable. Examples of the aromatic heterocycle 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, and a pyrazole ring. Thiazole ring, benzothiazole ring, thienothiazole ring, oxazole ring, benzoxazole ring, and phenanthroline ring. Among them, a thiazole ring, a benzothiazole ring, or a benzofuran ring is preferable, and a benzothiazole group is more preferable. When Ar contains a nitrogen atom, the nitrogen atom preferably has π electrons.

  In the formula (I), the total number Nπ of π electrons contained in the divalent aromatic group represented by Ar is preferably 8 or more, more preferably 10 or more, still more preferably 14 or more, and particularly preferably. Is 16 or more. Further, it is preferably 30 or less, more preferably 26 or less, and further preferably 24 or less.

  Examples of the aromatic group represented by Ar include the following groups.

In the formulas (Ar-1) to (Ar-23), an asterisk (*) represents a connecting part, and Z ⁰ , Z ¹ and Z ² each independently represent a hydrogen atom, a halogen atom, or an alkyl having 1 to 12 carbons. Group, cyano group, nitro group, alkylsulfinyl group having 1 to 12 carbon atoms, alkylsulfonyl group having 1 to 12 carbon atoms, carboxyl group, fluoroalkyl group having 1 to 12 carbon atoms, alkoxy group having 1 to 6 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 carbon Represents an N, N-dialkylsulfamoyl group of Formulas 2 to 12.

Q ^{1, Q 2} and ^{Q 3} are, each ^{independently, -CR 2 'R 3' -} , - S -, - NH -, - NR 2 '-, - represents CO- or O- a, R ^2' and R ^{3 ′} each independently represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms.

J ¹ and J ² each independently represent a carbon atom or a nitrogen atom.

Y ¹ , Y ² and Y ³ each independently represent an optionally substituted aromatic hydrocarbon group or aromatic heterocyclic group.

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

Examples of the aromatic hydrocarbon group for Y ¹ , Y ² and Y ³ include an aromatic hydrocarbon group having 6 to 20 carbon atoms such as a phenyl group, a naphthyl group, an anthryl group, a phenanthryl group and a biphenyl group. , A naphthyl group is preferred, and a phenyl group is more preferred. The aromatic heterocyclic group includes a nitrogen atom such as a furyl group, a pyrrolyl group, a thienyl group, a pyridinyl group, a thiazolyl group, a benzothiazolyl group, a heteroatom such as an oxygen atom or a sulfur atom, and has 4 to 20 carbon atoms. An aromatic heterocyclic group is mentioned, and a furyl group, a thienyl group, a pyridinyl group, a thiazolyl group, and a benzothiazolyl group are preferable.

Y ¹ , Y ² and Y ³ may each independently be a polycyclic aromatic hydrocarbon group or a polycyclic aromatic heterocyclic group which may be substituted. 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.

Preferably, Z ⁰ , Z ¹ and Z ² are each independently a hydrogen atom, a halogen atom, an alkyl group having 1 to 12 carbon atoms, a cyano group, a nitro group, or an alkoxy group having 1 to 12 carbon atoms. ⁰ is more preferably a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, and a cyano group, and Z ¹ and Z ² are more preferably a hydrogen atom, a fluorine atom, a chlorine atom, a methyl group, and a cyano group.

Q ¹ , Q ² and Q ³ are preferably -NH-, -S-, -NR ^{2 '} -and -O-, and R ^2' is preferably a hydrogen atom. Among them, -S-, -O-, and -NH- are particularly preferable.

Among the formulas (Ar-1) to (Ar-23), the formulas (Ar-6) and (Ar-7) are preferable from the viewpoint of molecular stability.
In the formulas (Ar-16) to (Ar-23), Y ¹ may form an aromatic heterocyclic group together with the nitrogen atom to which it is bonded and Z ⁰ . Examples of the aromatic heterocyclic group include those described above as the aromatic heterocyclic ring which 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, quinoline ring, isoquinoline ring, purine ring, pyrrolidine ring and the like. This aromatic heterocyclic group may have a substituent. In addition, Y ¹ may be the above-mentioned optionally substituted polycyclic aromatic hydrocarbon group or polycyclic aromatic heterocyclic group together with the nitrogen atom to which it is bonded and Z ⁰ . For example, a benzofuran ring, a benzothiazole ring, a benzoxazole ring and the like can be mentioned.

  The content of the polymerizable liquid crystal compound in the liquid crystal composition is usually 50 parts by mass or more and 99.5 parts by mass or less, preferably 60 parts by mass or more and 99 parts by mass with respect to 100 parts by mass of the solid content of the liquid crystal composition. Or less, more preferably 70 to 98 parts by mass, and still more preferably 80 to 97 parts by mass. When the content ratio of the polymerizable liquid crystal is within the above range, the orientation tends to be high. Here, the solid content refers to the total amount of components excluding the solvent from the liquid crystal composition.

  The liquid crystal composition preferably contains two or more polymerizable liquid crystal compounds from the viewpoint of reducing defects caused by microcrystals in the optically anisotropic layer. When the liquid crystal composition contains two or more polymerizable liquid crystal compounds, the liquid crystal composition may contain, for example, 90% by mass or less, preferably 85% by mass, of the main polymerizable liquid crystal compound based on the entire polymerizable liquid crystal compound. Includes:

  The liquid crystal composition may preferably contain a dimer, a trimer or a higher oligomer thereof together with the polymerizable liquid crystal compound from the viewpoint of improving the solubility in a solvent. Thereby, precipitation of microcrystals tends to be easily suppressed.

(solvent)
When the liquid crystal composition contains an organic solvent, since precipitation of crystals of the polymerizable liquid crystal compound contained in the liquid crystal composition can be suppressed, it is easy to suppress the occurrence of defects due to microcrystals in the optically anisotropic layer. There is a tendency. Further, when the liquid crystal composition contains an organic solvent, handling and film formation when forming an optical film tend to be easy. The solvent is preferably a solvent that can completely dissolve the polymerizable liquid crystal compound, and is preferably a solvent that is inert to the polymerization reaction of the polymerizable liquid crystal compound.

  Examples of the solvent include alcohol solvents such as methanol, ethanol, ethylene glycol, isopropyl alcohol, propylene glycol, ethylene glycol methyl ether, ethylene glycol butyl ether and propylene glycol monomethyl ether; ethyl acetate, butyl acetate, ethylene glycol methyl ether acetate, γ-butyrolactone Or ester solvents such as 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; And aromatic hydrocarbon solvents such as xylene, and nitrile solvents such as acetonitrile; Ether solvents such as hydrofuran and dimethoxyethane; chlorine-containing solvents such as chloroform and chlorobenzene; amide solvents such as dimethylacetamide, dimethylformamide, N-methyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone And the like. These solvents may be used alone or in combination of two or more.

  The content of the solvent is preferably from 50% by mass to 98% by mass based on the total amount of the liquid crystal composition. In other words, the solid content in the liquid crystal composition is preferably from 2% by mass to 50% by mass. When the content of the solid content is 50% by mass or less, the viscosity of the liquid crystal composition decreases, and thus the thickness of the polarizing layer 12 becomes substantially uniform, so that the polarizing layer 12 is less likely to have unevenness. Tend. Further, the content of the solid content can be determined in consideration of the thickness of the polarizing layer 12 to be manufactured.

(Polymerization initiator)
The liquid crystal composition may contain a polymerization initiator. The polymerization initiator is a compound that can initiate a polymerization reaction of a polymerizable liquid crystal or the like. From the viewpoint that the polymerization initiator does not depend on the phase state of the thermotropic liquid crystal, a photopolymerization initiator that generates an active radical by the action of light is preferable.

  Examples of the polymerization initiator include benzoin compounds, benzophenone compounds, alkylphenone compounds, acylphosphine oxide compounds, triazine compounds, iodonium salts and sulfonium salts.

  Examples of the benzoin compound include benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, and benzoin isobutyl ether.

  Examples of the benzophenone compound include benzophenone, methyl o-benzoylbenzoate, 4-phenylbenzophenone, 4-benzoyl-4′-methyldiphenylsulfide, 3,3 ′, 4,4′-tetra (tert-butylperoxycarbonyl) ) Benzophenone and 2,4,6-trimethylbenzophenone.

  Examples of the alkylphenone compound include diethoxyacetophenone, 2-methyl-2-morpholino-1- (4-methylthiophenyl) propan-1-one, and 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl ) Butan-1-one, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1,2-diphenyl-2,2-dimethoxyethan-1-one, 2-hydroxy-2-methyl-1 -[4- (2-hydroxyethoxy) phenyl] propan-1-one, 1-hydroxycyclohexylphenyl ketone and 2-hydroxy-2-methyl-1- [4- (1-methylvinyl) phenyl] propane-1- ON oligomers and the like.

  Examples of the acylphosphine oxide compound include 2,4,6-trimethylbenzoyldiphenylphosphine oxide and bis (2,4,6-trimethylbenzoyl) phenylphosphine oxide.

  Examples of the triazine compound include 2,4-bis (trichloromethyl) -6- (4-methoxyphenyl) -1,3,5-triazine and 2,4-bis (trichloromethyl) -6- (4-methoxy Naphthyl) -1,3,5-triazine, 2,4-bis (trichloromethyl) -6- (4-methoxystyryl) -1,3,5-triazine, 2,4-bis (trichloromethyl) -6 [2- (5-Methylfuran-2-yl) ethenyl] -1,3,5-triazine, 2,4-bis (trichloromethyl) -6- [2- (furan-2-yl) ethenyl] -1 , 3,5-triazine, 2,4-bis (trichloromethyl) -6- [2- (4-diethylamino-2-methylphenyl) ethenyl] -1,3,5-triazine and 2,4-bis (trichloromethyl Methyl) 6- [2- (3,4-dimethoxyphenyl) ethenyl] -1,3,5-triazine.

  Commercially available polymerization initiators can be used. Commercially available polymerization initiators include Irgacure (registered trademark) 907, 184, 651, 819, 250, and 369, 379, 127, 754, OXE01, OXE02, OXE03 (manufactured by Ciba Specialty Chemicals Co., Ltd.) Sake All (registered trademark) BZ, Z, and BEE (manufactured by Seiko Chemical Co., Ltd.); Kayacure (registered trademark) BP100, and UVI-6992 (manufactured by Dow Chemical Company); Adeka Optomer SP-152; N-1717, N-1919, SP-170, ADEKA ARKULS NCI-831, ADEKA ARKULS NCI-930 (manufactured by ADEKA Corporation); TAZ-A and TAZ-PP (manufactured by Nippon SiberHegner Co., Ltd.); TAZ-104 (Corporation Sum Chemical Co.); and the like. One type of polymerization initiator in the liquid crystal composition may be used, or two or more types of polymerization initiators may be mixed according to the light source of light.

  The content of the polymerization initiator in the liquid crystal composition can be appropriately adjusted depending on the type and the amount of the polymerizable liquid crystal compound, but usually 0.1 parts by mass with respect to 100 parts by mass of the polymerizable liquid crystal compound. It is 30 parts by mass or less, preferably 0.5 part by mass or more and 10 parts by mass or less, more preferably 0.5 part by mass or more and 8 parts by mass or less. When the content of the polymerization initiator is within the above range, polymerization can be performed without disturbing the alignment of the polymerizable liquid crystal.

(Sensitizer)
The liquid crystal composition may contain a sensitizer. As the sensitizer, a photosensitizer is preferable. Examples of the sensitizer include xanthone compounds such as xanthone and thioxanthone (eg, 2,4-diethylthioxanthone, 2-isopropylthioxanthone); and anthracene compounds such as anthracene and anthracene containing an alkoxy group (eg, dibutoxyanthracene). Phenothiazine and rubrene;

  When the liquid crystal composition contains a sensitizer, the polymerization reaction of the polymerizable liquid crystal compound contained in the liquid crystal composition can be further promoted. The amount of the sensitizer to be used is preferably from 0.1 to 10 parts by mass, more preferably from 0.5 to 5 parts by mass, based on 100 parts by mass of the polymerizable liquid crystal compound. 0.5 parts by mass or more and 3 parts by mass or less are more preferable.

(Polymerization inhibitor)
From the viewpoint of promoting the polymerization reaction stably, the liquid crystal composition may contain a polymerization inhibitor. The progress of the polymerization reaction of the polymerizable liquid crystal compound can be controlled by the polymerization inhibitor.

  Examples of the polymerization inhibitor include radical scavenging such as hydroquinone, alkoxy group-containing hydroquinone, alkoxy group-containing catechol (eg, butyl catechol), pyrogallol, 2,2,6,6-tetramethyl-1-piperidinyloxy radical, and the like. Agents; thiophenols; β-naphthylamines, β-naphthols and the like.

  When the liquid crystal composition contains a polymerization inhibitor, the content of the polymerization inhibitor is preferably 0.1 parts by mass or more and 10 parts by mass or less with respect to 100 parts by mass of the polymerizable liquid crystal compound, more preferably It is from 0.5 parts by mass to 5 parts by mass, more preferably from 0.5 parts by mass to 3 parts by mass. When the content of the polymerization inhibitor is within the above range, polymerization can be performed without disturbing the alignment of the polymerizable liquid crystal.

(Leveling agent)
The liquid crystal composition may contain a leveling agent. Leveling agents are additives having a function of adjusting the fluidity of the composition and making the film obtained by applying the composition more flat, and include, for example, organically modified silicone oils, polyacrylates, and perfluorocarbons. Alkyl-based leveling agents are exemplified. Specifically, DC3PA, SH7PA, DC11PA, SH28PA, SH29PA, SH30PA, ST80PA, ST86PA, SH8400, SH8700, FZ2123 (all manufactured by Dow Corning Toray Co., Ltd.), KP321, KP323, KP324, KP326, KP340 KP341, X22-161A, KF6001 (all manufactured by Shin-Etsu Chemical Co., Ltd.), TSF400, TSF401, TSF410, TSF4300, TSF4440, TSF4445, TSF-4446, TSF4452, TSF4460 (all are all Momentive Performance Materials Japan GK) Fluorinert (registered trademark) FC-72, FC-40, FC-43, FC-3283 Manufactured by Sumitomo 3M Limited), Megafac (registered trademark) R-08, R-30, R-90, F-410, F-411, F-443, F-445, F-445 F-470, F-474, F-479, F-482, F-483 (all manufactured by DIC Corporation), F-top (trade name) EF301, EF303, EF351, EF352 (all manufactured by Mitsubishi Materials Electronic Chemicals, Inc.), Surflon (registered trademark) S-381, S-382, S-383, S-393, SC-101, SC-105, KH -40, SA-100 (all, manufactured by AGC Seimi Chemical Co., Ltd.), trade names E1830, E5844 (manufactured by Daikin Fine Chemical Laboratory Co., Ltd.), BM-1000, BM-1100, BYK-352, BY -353 and BYK-361N (both trade name: BM Chemie Co., Ltd.), and the like. Among them, polyacrylate-based leveling agents and perfluoroalkyl-based leveling agents are preferred.

  When the liquid crystal composition contains a leveling agent, it is preferably 0.01 to 5 parts by mass, more preferably 0.1 to 5 parts by mass, based on 100 parts by mass of the polymerizable liquid crystal compound. The content is more preferably 0.1 part by mass or more and 3 parts by mass or less. When the content of the leveling agent is within the above range, the polymerizable liquid crystal compound can be easily horizontally aligned, and the obtained polarizing film tends to be smoother. When the content of the leveling agent with respect to the polymerizable liquid crystal compound exceeds the above range, unevenness tends to occur in the obtained polarizing film. The liquid crystal composition may contain two or more leveling agents.

  The film thickness can be adjusted so as to give a desired retardation by appropriately adjusting the coating amount and the concentration of the liquid crystal composition. In the case of a liquid crystal composition in which the amount of the polymerizable liquid crystal compound is constant, the retardation value (retardation value, Re (λ)) of the obtained retardation film is determined as in the following equation (a). The thickness d may be adjusted in order to obtain a desired Re (λ).

Re (λ) = d × Δn (λ) (a)
[Wherein, Re (λ) represents a retardation value at a wavelength of λ nm, d represents a film thickness, and Δn (λ) represents a birefringence at a wavelength of λ nm]

(Coating of liquid crystal composition)
Examples of the method of applying the liquid crystal composition on a substrate or an alignment film include extrusion coating, direct gravure coating, reverse gravure coating, CAP coating, slit coating, microgravure, die coating, and ink jet method. Is mentioned. Further, a coating method using a coater such as a dip coater, a bar coater, and a spin coater may be used. Among them, a microgravure method, an ink-jet method, a slit coating method, and a die coating method are preferred for continuous application in a roll-to-roll format. High spin coating methods are preferred. When applying in a roll-to-roll format, a composition for forming a photo-alignment film for forming an alignment film on a base material is applied to form an alignment film, and a liquid crystal composition is continuously formed on the obtained alignment film. It can also be applied in a targeted manner.

  The base material on which the liquid crystal composition is applied tends to reduce the number of specific defects caused by microcrystals by keeping the temperature at a constant temperature when applying the liquid crystal composition. The temperature for keeping the temperature may be, for example, 20 ° C. or more and 60 ° C. or less, and preferably 30 ° C. or more and 50 ° C. or less.

  From the viewpoint of increasing the uniformity of the polymerizable liquid crystal compound coating film and reducing the number of specific defects caused by repelling of the polymerizable liquid crystal compound film and defective alignment film, the surface smoothness of the substrate is improved by annealing. Can be enhanced. The annealing temperature may be, for example, 60 ° C. or more and 100 ° C. or less, or 5 ° C. or more and 20 ° C. or less lower than the glass transition point of the substrate, and the time may be 1 second or more and 60 seconds or less, for example.

  By making the humidity of the surrounding atmosphere constant during coating, crystallization of the polymerizable liquid crystal compound is easily suppressed, and the number of specific defects due to microcrystals tends to be reduced. The humidity of the surrounding atmosphere may be, for example, 90% RH or less, preferably 85% RH or less, more preferably 60% RH or less, further preferably 55% RH or less, and particularly preferably 40% RH. It is as follows. On the other hand, the humidity of the surrounding atmosphere at the time of coating may be, for example, 10% RH or more, and preferably 20% RH or more. When using a polymerizable liquid crystal compound having a relatively large molecular weight, the humidity at the time of coating the polymerizable liquid crystal compound on a substrate may be relatively low so that the number of specific defects is within the range specified in the present invention. it can.

  By adjusting the atmosphere around the die used for coating to the vapor pressure of the solvent contained in the polymerizable liquid crystal compound (under the solvent atmosphere), the solvent of the polymerizable liquid crystal compound is less likely to volatilize, and the crystal of the polymerizable liquid crystal compound is crystallized. And the number of specific defects due to microcrystals tends to decrease.

  The base material is preferably cleaned from the viewpoint of reducing the number of specific defects caused by foreign matters, before coating the liquid crystal composition, to remove surface contamination, for example, PET lubricant, PET oligomer, silicone oil, and the like. Can be.

  In order to remove foreign substances, microcrystals, and the like in the liquid crystal composition to be coated, filtering can be performed before coating, preferably immediately before coating. Further, by performing the application of the liquid crystal composition in a clean room, the number of specific defects due to foreign matter can be reduced.

(Drying of liquid crystal composition)
Examples of the drying method for removing the solvent contained in the liquid crystal composition include natural drying, ventilation drying, heat drying, drying under reduced pressure, and a combination thereof. Above all, natural drying or heat drying is preferable. The drying temperature may be, for example, in the range of 0 ° C to 200 ° C, for example, more preferably in the range of 20 ° C to 150 ° C, and even more preferably in the range of 50 ° C to 130 ° C. The drying time may be, for example, from 10 seconds to 10 minutes, and preferably from 30 seconds to 5 minutes. The oriented polymer composition can be dried as well.

(Polymerization of polymerizable liquid crystal compound)
As a method for polymerizing the polymerizable liquid crystal compound, photopolymerization is preferable. The photopolymerization is carried out by irradiating an active energy ray to a laminate in which a liquid crystal composition is coated with a polymerizable liquid crystal compound on a substrate or an alignment film. The type of the polymerizable liquid crystal compound contained in the dried film (particularly, the type of the photopolymerizable functional group included in the polymerizable liquid crystal compound) as the active energy ray to be irradiated, and the photopolymerization initiator when the photopolymerization initiator is contained. Are appropriately selected in accordance with the types and the amounts thereof. Specifically, it includes at least one kind of light selected from the group consisting of visible light, ultraviolet light, infrared light, X-ray, α-ray, β-ray, and γ-ray. Above all, ultraviolet light is preferable in that it is easy to control the progress of the polymerization reaction and that a photopolymerization apparatus that is widely used in this field can be used. It is preferable to select the type of the liquid crystal compound.

  Examples of the light source of the active energy ray include a low-pressure mercury lamp, a medium-pressure mercury lamp, a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, a xenon lamp, a halogen lamp, a carbon arc lamp, a tungsten lamp, a gallium lamp, an excimer laser, and a wavelength range. Examples include an LED light source that emits light of 380 nm or more and 440 nm or less, a chemical lamp, a black light lamp, a microwave-excited mercury lamp, and a metal halide lamp.

Ultraviolet irradiation intensity is usually, 10 mW / cm ² or more 3,000 mW / cm ² or less. The ultraviolet irradiation intensity is preferably an intensity in a wavelength region effective for activating a cationic polymerization initiator or a radical polymerization initiator. The time for irradiating light is usually 0.1 second or more and 10 minutes or less, preferably 0.1 second or more and 5 minutes or less, more preferably 0.1 second or more and 3 minutes or less, and further preferably 0 second or less. It is 1 second or more and 1 minute or less. When such irradiation one or more times with ultraviolet irradiation intensity, the integrated quantity of light, 10 mJ / cm ² or more 3,000 mJ / cm ² or less, preferably 50 mJ / cm ² or more 2,000 mJ / cm ² or less, more preferably is 100mJ / cm ² or more 1,000mJ / cm ² or less. When the integrated light amount is within this range, curing of the polymerizable liquid crystal compound becomes sufficient, good transferability is easily obtained, and coloring of the optical laminate tends to be easily suppressed.

  FIG. 1 is a schematic view illustrating an embodiment of an optical film according to an aspect of the present invention. The optical film 10 has an optically anisotropic layer 11, an alignment layer 12, and a base layer 13 in this order.

[Retardation laminate]
The retardation laminate includes one or more optical films described above. The retardation laminate has one or more retardation layers, and is used, for example, to convert linearly polarized light into circularly polarized light or elliptically polarized light, or to convert circularly or elliptically polarized light into linearly polarized light. It may be.

  When the retardation laminate has a first retardation layer and a second retardation layer, the retardation laminate can be bonded to a polarizing plate and used as a circularly polarizing plate. When used as a circularly polarizing plate, the first retardation layer may be a quarter-wave retardation layer having reverse wavelength dispersion and the second retardation layer may be a positive C plate, or the first retardation layer may be a positive C plate. The second retardation layer may be a 波長 wavelength retardation layer, and the second retardation layer may be a 波長 wavelength retardation layer.

  The retardation laminate will be described with reference to the drawings.

  FIG. 2 is a schematic diagram showing one embodiment of the retardation laminate. The retardation laminate 20 includes a first base material layer 31, a first alignment layer 32, a first retardation layer 33, an adhesive layer 34, a second retardation layer 35, It has an orientation layer 36 and a second base material layer 37 in this order.

  The first laminate 21 composed of the first base layer 31, the first alignment layer 32, and the first retardation layer 33 can be composed of the above-described optical film 10 of the present invention.

  The second laminate 22 composed of the second retardation layer 35, the second alignment layer 36, and the second base layer 37 can be composed of the above-described optical film 10 of the present invention.

  The adhesive layer 34 can be formed from an adhesive, an adhesive, or a combination thereof. The adhesive layer 34 is usually one layer, but may be two or more layers. The adhesive layer 34 may be formed by applying the adhesive composition to the bonding surface of the base material layer or the phase difference layer. As a coating method, a normal coating technique using a die coater, a comma coater, a reverse roll coater, a gravure coater, a rod coater, a wire bar coater, a doctor blade coater, an air doctor coater, or the like may be used.

  As the adhesive, (meth) acrylic adhesive, styrene adhesive, silicone adhesive, rubber adhesive, urethane adhesive, polyester adhesive, epoxy copolymer adhesive, etc. may be used. it can.

  The adhesive can be formed, for example, by combining one or more of a water-based adhesive, an active energy ray-curable adhesive, a pressure-sensitive adhesive and the like. Examples of the water-based adhesive include a polyvinyl alcohol-based resin aqueous solution, a water-based two-part urethane emulsion adhesive, and the like. The active energy ray-curable adhesive is an adhesive that is cured by irradiating active energy rays such as ultraviolet rays, for example, those containing a polymerizable compound and a photopolymerizable initiator, those containing a photoreactive resin, Examples include those containing a binder resin and a photoreactive crosslinker. Examples of the polymerizable compound include photopolymerizable monomers such as photocurable epoxy monomers, photocurable acrylic monomers, and photocurable urethane monomers, and oligomers derived from these monomers. Examples of the photopolymerization initiator include those containing a substance that generates active species such as neutral radicals, anion radicals, and cation radicals when irradiated with active energy rays such as ultraviolet rays.

  The thickness of the adhesive layer 34 may be, for example, 0.1 μm or more and 25 μm or less, preferably 0.5 μm or more and 20 μm or less, more preferably 1 μm or more and 15 μm or less, further preferably 2 μm or more and 10 μm or less, and particularly preferably 2.5 μm or less. Not less than 5 μm.

  The retardation laminate 20 is prepared by, for example, preparing a first laminate 21 and a second retardation layer 22, and forming an adhesive layer 34 on the surface of the first laminate 21 on the side of the first retardation layer 33. Can be manufactured by a manufacturing method including a step of bonding the first laminate 21 and the second retardation layer 22 to each other with the respective retardation layer surface sides as sticking surfaces.

[Polarizer]
By combining the above-mentioned retardation laminate and a polarizer, a polarizing plate, for example, an elliptically polarizing plate and a circularly polarizing plate are provided.

  Since the polarizing plate of the present invention has an optically anisotropic layer with improved film strength and workability, cracks and the like tend not to occur even when cut. Therefore, the polarizing plate of the present invention is suitable for a polarizing plate having a cut surface or a deformed polarizing plate. The odd-shaped polarizing plate may be, for example, a polarizing plate having a planar shape other than a rectangular shape or a square shape, or a polarizing plate having a through hole in a planar region inside from the outermost periphery. The polarizing plate may be in a long shape or a sheet shape.

  FIG. 3 is a schematic view showing an embodiment of the polarizing plate. The polarizing plate 40 includes a polarizer 39, an adhesive layer 38, a first alignment layer 32, a first retardation layer 33, an adhesive layer 34, a second retardation layer 35, and a second alignment layer. It has a layer 36 and a second base material layer 37 in this order.

  As the polarizer 39, any appropriate polarizer can be adopted. The polarizer is a linear polarizer having a property of transmitting linearly polarized light having a vibration plane orthogonal to an absorption axis when unpolarized light is incident. For example, the resin film forming the polarizer may be a single-layer resin film or a laminated film of two or more layers. The polarizer 39 may be a cured film obtained by aligning a dichroic dye on a polymerizable liquid crystal compound and polymerizing the polymerizable liquid crystal compound.

  Specific examples of the polarizer composed of a single-layer resin film include a polyvinyl alcohol (hereinafter sometimes abbreviated as “PVA”) film, a partially formalized PVA film, and ethylene / vinyl acetate copolymer. A hydrophilic polymer film such as a partially saponified film that has been subjected to a dyeing treatment with a dichroic substance such as iodine or a dichroic dye, and a stretching treatment. Examples thereof include polyene-based oriented films such as hydrochloric acid-treated products. From the viewpoint of excellent optical properties, it is preferable to use a polarizer obtained by dyeing a PVA-based film with iodine and uniaxially stretching the film.

  The polyvinyl alcohol resin can be produced by saponifying a polyvinyl acetate resin. The polyvinyl acetate-based resin may be a copolymer of vinyl acetate and another monomer copolymerizable with vinyl acetate, in addition to polyvinyl acetate which is a homopolymer of vinyl acetate. Examples of other monomers copolymerizable with vinyl acetate include unsaturated carboxylic acids, olefins, vinyl ethers, unsaturated sulfonic acids, and acrylamides having an ammonium group.

  The degree of saponification of the polyvinyl alcohol-based resin is generally 85 mol% or more and 100 mol% or less, and preferably 98 mol% or more. The polyvinyl alcohol-based resin may be modified. For example, polyvinyl formal or polyvinyl acetal modified with aldehydes may be used. The polymerization degree of the polyvinyl alcohol-based resin is usually 1,000 or more and 10,000 or less, and preferably 1,500 or more and 5,000 or less.

  A film formed of such a polyvinyl alcohol-based resin is used as a raw film of a polarizer. The method of forming the polyvinyl alcohol-based resin is not particularly limited, and the film can be formed by a known method. The film thickness of the raw polyvinyl alcohol resin film is, for example, 10 μm or more and 100 μm or less, preferably 10 μm or more and 60 μm or less, and more preferably 15 μm or more and 30 μm or less.

  As another method of manufacturing the polarizer 39, first, a base film is prepared, a solution of a resin such as a polyvinyl alcohol-based resin is applied to the base film, and drying is performed to remove the solvent. And a step including a step of forming a resin layer. In addition, a primer layer can be previously formed on the surface of the base film on which the resin layer is formed. As the base film, a resin film such as PET can be used. Examples of the material for the primer layer include a resin obtained by crosslinking a hydrophilic resin used for a polarizer.

  Next, if necessary, the amount of the solvent such as water in the resin layer is adjusted, and thereafter, the base film and the resin layer are uniaxially stretched, and then the resin layer is dyed with a dichroic dye such as iodine to obtain two colors. The reactive dye is adsorbed and oriented on the resin layer. Subsequently, if necessary, the resin layer on which the dichroic dye is adsorbed and oriented is treated with a boric acid aqueous solution, and a washing step of washing off the boric acid aqueous solution is performed. Thus, a resin layer in which the dichroic dye is adsorbed and oriented, that is, a polarizer film is manufactured. A known method can be employed for each step.

  The uniaxial stretching of the base film and the resin layer may be performed before dyeing, may be performed during dyeing, or may be performed during boric acid treatment after dyeing. Stretching may be performed. The base film and the resin layer may be uniaxially stretched in the MD direction (film transport direction), and in this case, may be uniaxially stretched between rolls having different peripheral speeds, or may be uniaxially stretched using a hot roll. May be. Further, the base film and the resin layer may be uniaxially stretched in the TD direction (direction perpendicular to the film transport direction), and in this case, a so-called tenter method can be used. The stretching of the base film and the resin layer may be dry stretching in which the stretching is performed in the air or wet stretching in which the resin layer is swollen with a solvent. In order to exhibit the performance of the polarizer, the stretching ratio is 4 times or more, preferably 5 times or more, and particularly preferably 5.5 times or more. Although there is no particular upper limit for the stretching ratio, it is preferably 8 times or less from the viewpoint of suppressing breakage and the like.

  The polarizer 39 manufactured by the above method can be obtained by laminating a protective layer described later and then peeling the base film. According to this method, it is possible to further reduce the thickness of the polarizer.

  A method for manufacturing a polarizer 39, which is a cured film obtained by orienting a dichroic dye in a polymerizable liquid crystal compound and polymerizing the polymerizable liquid crystal compound, includes, on a base film, a polymerizable liquid crystal compound and a dichroic dye. A method for forming a polarizer by applying a polarizer-forming composition containing the same and polymerizing and polymerizing the polymerizable liquid crystal compound while maintaining the liquid crystal state, to form a polarizer. The polarizer thus obtained is in a state of being laminated on a base film, and may be used as a polarizer with a base film. Alternatively, the base film may be peeled and used after laminating the polarizer with the base film on the retardation laminate via the adhesive layer or after laminating on the adhesive layer with the release layer.

  As the dichroic dye, a dye having a property in which the absorbance in the major axis direction and the absorbance in the minor axis direction are different from each other can be used. For example, the dichroic dye has a maximum absorption wavelength (λmax) in a range of 300 nm or more and 700 nm or less. Dyes are preferred. Such dichroic dyes include, for example, acridine dyes, oxazine dyes, cyanine dyes, naphthalene dyes, azo dyes, anthraquinone dyes and the like, among which azo dyes are preferred. Examples of the azo dye include a monoazo dye, a bisazo dye, a trisazo dye, a tetrakisazo dye, and a stilbene azo dye, and a bisazo dye and a trisazo dye are more preferable.

  The composition for forming a polarizer can include a solvent, a polymerization initiator such as a photopolymerization initiator, a photosensitizer, a polymerization inhibitor, and the like. As the polymerizable liquid crystal compound, dichroic dye, solvent, polymerization initiator, photosensitizer, polymerization inhibitor, and the like contained in the polarizer-forming composition, known compounds can be used. Those exemplified in JP-A-2017-102479 and JP-A-2017-83843 can be used. As the polymerizable liquid crystal compound, the same compounds as those exemplified as the polymerizable liquid crystal compound used for obtaining the above-described optically anisotropic layer may be used. As a method of forming a polarizer using the composition for forming a polarizer, the method exemplified in the above publication can be employed.

  The thickness of the polarizer 39 may be, for example, 2 μm or more, and preferably 3 μm or more. On the other hand, the thickness of the polarizer 39 is, for example, 25 μm or less, and preferably 15 μm or less. Note that the upper limit and the lower limit described above can be arbitrarily combined. As the thickness of the polarizer 39 decreases, the rigidity decreases, and the polarizer 39 tends to be affected by the contraction stress of the optically anisotropic layer.

  The polarizer 39 can have a protective layer laminated on one or both sides thereof through a known adhesive layer or adhesive layer. The protective layer that can be laminated on one or both surfaces of the polarizer 39 is formed of, for example, a thermoplastic resin having excellent transparency, mechanical strength, thermal stability, moisture barrier properties, isotropy, stretchability, and the like. Film is used. Specific examples of such a thermoplastic resin include cellulose resins such as triacetyl cellulose; polyester resins such as polyethylene terephthalate and polyethylene naphthalate; polyether sulfone resins; polysulfone resins; polycarbonate resins; polyamides such as nylon and aromatic polyamides. Resin; Polyimide resin; Polyolefin resin such as polyethylene, polypropylene, ethylene-propylene copolymer; Cyclic and norbornene-structured cyclic polyolefin resin (also referred to as norbornene resin); (Meth) acrylic resin; Polyarylate resin; A polyvinyl alcohol resin, and a mixture thereof. When protective layers are laminated on both surfaces of the polarizer 39, the resin compositions of the two protective layers may be the same or different. In this specification, “(meth) acryl” means that either acryl or methacryl may be used. "(Meth)" such as (meth) acrylate has the same meaning.

  The film formed from the thermoplastic resin may be subjected to a surface treatment (for example, corona treatment) in order to improve the adhesion to a polarizer made of a PVA-based resin and a dichroic substance, and a primer layer A thin layer such as an undercoat layer may be formed.

  The protective layer may be, for example, a stretched or unstretched version of the thermoplastic resin described above (hereinafter, may be referred to as an “unstretched resin”). Examples of the stretching treatment include uniaxial stretching and biaxial stretching.

  The thickness of the protective layer may be, for example, 3 μm or more, and preferably 5 μm or more. On the other hand, the thickness of the protective layer may be, for example, 50 μm or less, and preferably 30 μm or less. Note that the upper limit and the lower limit described above can be arbitrarily combined.

  The surface of the protective layer opposite to the polarizer may have a surface treatment layer, for example, may have a hard coat layer, an anti-reflection layer, an anti-sticking layer, an anti-glare layer, a diffusion layer, and the like. . The surface treatment layer may be another layer laminated on the protective layer, or may be a layer formed by performing a surface treatment on the surface of the protective layer.

  The hard coat layer is for the purpose of preventing the surface of the polarizing plate from being scratched, for example, by adding a cured film having excellent hardness and sliding properties to the surface of the protective layer by an ultraviolet curable resin such as an acrylic or silicone resin. It can be formed by a method or the like. The antireflection layer is intended to prevent reflection of external light on the polarizing plate surface, and can be achieved by forming an antireflection film or the like according to the related art. The anti-sticking layer is intended to prevent adhesion to an adjacent layer.

  The anti-glare layer is provided for the purpose of preventing external light from being reflected on the surface of the polarizing plate and hindering the visibility of the transmitted light from the polarizing plate. The protective layer can be formed by imparting a fine uneven structure to the surface of the protective layer by a method such as a forming method or a method of mixing transparent fine particles. Examples of the transparent fine particles used for providing the fine uneven structure on the surface of the protective layer include silica, alumina, titania, zirconia, tin oxide, indium oxide, cadmium oxide, and antimony oxide having an average particle diameter of 0.5 μm or more and 50 μm or less. And fine particles such as organic fine particles such as a crosslinked or uncrosslinked polymer. The content of the transparent fine particles is generally from 2 parts by mass to 50 parts by mass, preferably from 5 parts by mass to 25 parts by mass, based on 100 parts by mass of the resin constituting the layer forming the fine uneven structure. The anti-glare layer may also serve as a diffusion layer (viewing angle expanding function, etc.) for expanding the viewing angle and the like by diffusing light transmitted through the polarizing plate.

  When the surface treatment layer is another layer laminated on the protective layer of the polarizing plate, the thickness of the surface treatment layer may be, for example, 0.5 μm or more, and preferably 1 μm or more. On the other hand, the thickness of the surface treatment layer may be, for example, 10 μm or less, and preferably 8 μm or less. When the thickness is within the above range, it is easy to effectively prevent the polarizing plate surface from being damaged, the curing shrinkage is suppressed, and the reverse curl of the polarizing plate tends to be easily suppressed.

  The adhesive layer 38 can be composed of an adhesive. As the pressure-sensitive adhesive, a conventionally known pressure-sensitive adhesive having excellent optical transparency can be used without particular limitation. For example, an acrylic, urethane, silicone, or a pressure-sensitive adhesive having a base polymer such as polyvinyl ether is used. be able to. Further, an active energy ray-curable pressure-sensitive adhesive, a thermosetting pressure-sensitive adhesive, or the like may be used. Among these, a pressure-sensitive adhesive using an acrylic resin as a base polymer having excellent transparency, adhesive strength, removability, weather resistance, heat resistance and the like is preferable. The pressure-sensitive adhesive layer is preferably composed of a reaction product of a pressure-sensitive adhesive composition containing a (meth) acrylic resin, a crosslinking agent, and a silane compound.

  The adhesive composition is mixed with an ultraviolet curable compound such as a polyfunctional acrylate to form an active energy ray-curable pressure-sensitive adhesive. It is also useful to form a harder adhesive layer. The active energy ray-curable pressure-sensitive adhesive has a property of being cured by irradiation with energy rays such as ultraviolet rays and electron beams. Activated energy ray-curable pressure-sensitive adhesives have adhesiveness even before irradiation with energy rays, so they adhere to adherends such as optical films and liquid crystal layers, and are cured by irradiation with energy rays to improve adhesion. It is an adhesive with properties that can be adjusted.

  The active energy ray-curable pressure-sensitive adhesive generally contains an acrylic pressure-sensitive adhesive and an energy ray-polymerizable compound as main components. Usually, a crosslinking agent is further blended, and if necessary, a photopolymerization initiator, a photosensitizer and the like can be blended.

  The thickness of the adhesive layer 38 may be, for example, 3 μm or more and 40 μm or less, and preferably 3 μm or more and 30 μm or less.

[Flexible image display device]
The flexible image display device includes a laminate for a flexible image display device and an organic EL display panel. The laminate for a flexible image display device is arranged on the viewing side with respect to the organic EL display panel, and is configured to be bendable. I have. Foldable means able to bend without cracking and breaking. The flexible image display device laminate may be a polarizing plate including at least one of a front plate and a touch sensor. When the polarizing plate has both the front plate and the touch sensor, the lamination order is arbitrary, but the front plate, the polarizing plate, and the touch sensor are arranged in this order from the viewing side, or the front plate, the touch sensor, and the polarizing plate are arranged from the viewing side. Are preferably stacked in this order. The presence of the polarizing plate on the viewing side of the touch sensor is preferable because the pattern of the touch sensor is hardly viewed and the visibility of the displayed image is improved. Each member can be laminated using an adhesive, a pressure-sensitive adhesive or the like. Further, a light-shielding pattern formed on at least one surface of any one of a front plate, a polarizing plate, and a touch sensor can be provided. Each layer (a front plate, a polarizing plate, a touch sensor) forming a laminate for a flexible image display device and a film member (a linear polarizing plate, a quarter-wave retardation plate, etc.) constituting each layer may be formed with an adhesive. it can. The polarizing plate is a polarizing plate containing the optical film or the retardation laminate of the present invention, and is preferably a circular polarizing plate. Further, the polarizing plate may be a polarizing plate having a cut surface or a deformed polarizing plate.

(Front plate)
The front plate is preferably a plate-like body capable of transmitting light. The front plate may be composed of only one layer, or may be composed of two or more layers. The front plate may have not only a function (window) for protecting the front surface (screen) of the image display device, but also a function as a touch sensor, a blue light cut function, a viewing angle adjustment function, and the like. The front plate is preferably a window.

(Window)
The window is disposed, for example, on the viewing side of a flexible image display device described later, and has a role of protecting other components from external impact or environmental changes such as temperature and humidity. Conventionally, glass has been used as such a protective layer, but a window in a flexible image display device to be described later is not rigid and rigid like 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.

(Transparent substrate)
The transparent substrate has a visible light transmittance of 70% or more, preferably 80% or more. As the transparent substrate, any transparent polymer film can be used. Specifically, polyolefins such as polyethylene, polypropylene, polymethylpentene, norbornene or cycloolefin derivatives having a monomer unit containing cycloolefin, and (modified) cellulose such as diacetylcellulose, triacetylcellulose, and propionylcellulose , Acrylics such as methyl methacrylate (co) polymer, polystyrenes such as styrene (co) polymer, acrylonitrile-butadiene-styrene copolymer, acrylonitrile-styrene copolymer, ethylene-vinyl acetate copolymer , Polyvinyl chloride, polyvinylidene chloride, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polyesters such as polycarbonate and polyarylate, polyamides such as nylon Polyimides, polyamideimides, polyetherimides, polyethersulfones, polysulfones, polyvinyl alcohols, polyvinylacetals, polyurethanes, may be a film formed of a polymer such as an epoxy resin, Unstretched uniaxially or biaxially stretched films can be used. These polymers can be used alone or in combination of two or more. Preferably, a polyamide film, a polyamide imide film or a polyimide film, a polyester film, an olefin film, an acrylic film, and a cellulose film excellent in transparency and heat resistance among the above transparent substrates are preferable. It is also preferable to disperse inorganic particles such as silica, organic fine particles, and rubber particles in the polymer film. In addition, colorants such as pigments and dyes, fluorescent brighteners, dispersants, plasticizers, heat stabilizers, light stabilizers, infrared absorbers, ultraviolet absorbers, antistatic agents, antioxidants, lubricants, solvents, etc. May be contained. The thickness of the transparent substrate is 5 μm or more and 200 μm or less, preferably 20 μm or more and 100 μm or less.

(Hard coat)
The window may be provided with a hard coat layer on at least one surface of the transparent substrate. The thickness of the hard coat layer is not particularly limited, and may be, for example, 2 μm or more and 100 μm or less. When the thickness of the hard coat layer is less than 2 μm, it is difficult to secure sufficient scratch resistance, and when it exceeds 100 μm, the bending resistance is reduced and a problem of curling due to curing shrinkage may occur.

  The hard coat layer can be formed by curing a hard coat composition containing a reactive material that forms a crosslinked structure by irradiating active energy rays or heat energy, but is preferably formed by active energy ray curing. An active energy ray is defined as an energy ray that can decompose a compound that generates an active species to generate an active species. Examples of the active energy ray include visible light, ultraviolet light, infrared light, X-ray, α-ray, β-ray, γ-ray, and electron beam. Ultraviolet light is particularly preferred. The hard coat composition contains at least one polymer of a radically polymerizable compound and a cationically polymerizable compound.

  The radical polymerizable compound is a compound having a radical polymerizable group. The radically polymerizable group of the radically polymerizable compound may be any functional group capable of causing a radical polymerization reaction, and examples thereof include a group containing a carbon-carbon unsaturated double bond. Specific examples include a vinyl group and a (meth) acryloyl group. When the radical polymerizable compound has two or more radical polymerizable groups, these radical polymerizable groups may be the same or different. The number of radically polymerizable groups in the molecule of the radically polymerizable compound is preferably two or more from the viewpoint of improving the hardness of the hard coat layer. As the radical polymerizable compound, a compound having a (meth) acryloyl group is particularly preferable from the viewpoint of high reactivity, and is referred to as a polyfunctional acrylate monomer having 2 to 6 (meth) acryloyl groups in one molecule. Preferably used are oligomers having several (meth) acryloyl groups in a molecule called a compound or epoxy (meth) acrylate, urethane (meth) acrylate, or polyester (meth) acrylate having a molecular weight of several hundred to several thousand. it can. It preferably contains at least one selected from epoxy (meth) acrylate, urethane (meth) acrylate and polyester (meth) acrylate.

  The cationically polymerizable compound is a compound having a cationically polymerizable group such as an epoxy group, an oxetanyl group, and a vinyl ether group. The number of cationically polymerizable groups contained in one molecule of the cationically polymerizable compound is preferably two or more, and more preferably three or more, from the viewpoint of improving the hardness of the hard coat layer. As the cationically polymerizable compound, a compound having at least one of an epoxy group and an oxetanyl group as the cationically polymerizable group is particularly preferable. Cyclic ether groups such as an epoxy group and an oxetanyl group are preferable in that shrinkage due to the polymerization reaction is small. In addition, among the cyclic ether groups, compounds having an epoxy group are easily available in compounds having various structures, do not adversely affect the durability of the obtained hard coat layer, and easily control compatibility with the radical polymerizable compound. There is an advantage. In addition, the oxetanyl group among the cyclic ether groups has a higher degree of polymerization than the epoxy group, is low in toxicity, hastens the rate of network formation obtained from the cationically polymerizable compound in the obtained hard coat layer, and has a radical Even in a region where the polymerizable compound is mixed, there is an advantage that an unreacted monomer is not left in the film and an independent network is formed.

  Examples of the cationically polymerizable compound having an epoxy group include, for example, a polyglycidyl ether of a polyhydric alcohol having an alicyclic ring, or a cyclohexene ring or a cyclopentene ring-containing compound, which is treated with a suitable oxidizing agent such as hydrogen peroxide or peracid. Alicyclic epoxy resin obtained by epoxidation; polyglycidyl ether of aliphatic polyhydric alcohol or its alkylene oxide adduct, polyglycidyl ester of aliphatic long-chain polybasic acid, homopolymer of glycidyl (meth) acrylate, Aliphatic epoxy resins such as copolymers; bisphenols such as bisphenol A, bisphenol F and hydrogenated bisphenol A, or glycidyl ethers produced by reacting derivatives thereof such as alkylene oxide adducts and caprolactone adducts with epichlorohydrin Ether, and novolac epoxy resins such as a and glycidyl ether type epoxy resins derived from bisphenols are exemplified.

  The hard coat composition may further include a polymerization initiator. Examples of the polymerization initiator include a radical polymerization initiator, a cationic polymerization initiator, a radical and cationic polymerization initiator, and the like can be appropriately selected and used. These polymerization initiators are decomposed by at least one of active energy ray irradiation and heating to generate radicals or cations, thereby promoting radical polymerization and cationic polymerization.

  The radical polymerization initiator only needs to be capable of releasing a substance that initiates radical polymerization by at least one of irradiation with active energy rays and heating. For example, examples of the thermal radical polymerization initiator include organic peroxides such as hydrogen peroxide and perbenzoic acid, and azo compounds such as azobisbutyronitrile.

  Examples of the active energy ray radical polymerization initiator include a Type 1 radical polymerization initiator in which radicals are generated by decomposition of a molecule and a Type 2 radical polymerization initiator in which a radical is generated by a hydrogen abstraction reaction in the presence of a tertiary amine. Yes, they can be used alone or in combination.

  The cationic polymerization initiator only needs to be capable of releasing a substance that initiates cationic polymerization by at least one of irradiation with active energy rays and heating. As the cationic polymerization initiator, an aromatic iodonium salt, an aromatic sulfonium salt, a cyclopentadienyl iron (II) complex and the like can be used. These can initiate cationic polymerization by active energy ray irradiation and / or heating depending on the difference in structure.

  The polymerization initiator may include 0.1 to 10% by weight based on 100% by weight of the entire hard coat composition. When the content of the polymerization initiator is less than 0.1% by weight, the curing cannot be sufficiently advanced, and it is difficult to realize the mechanical properties and adhesion of the finally obtained coating film, and it is difficult to achieve the adhesion of 10% by weight. %, Adhesive strength failure due to curing shrinkage, cracking phenomenon and curl phenomenon may occur.

  The hard coat composition may further include at least one selected from the group consisting of a solvent and an additive. The solvent is capable of dissolving or dispersing the polymerizable compound and the polymerization initiator, and may be used without any limitation as long as it is known as a solvent for a hard coat composition in the technical field. The additive may further include inorganic particles, a leveling agent, a stabilizer, a surfactant, an antistatic agent, a lubricant, an antifouling agent, and the like.

(Circularly polarizing plate)
The circularly polarizing plate is a functional layer having a function of transmitting only the right or left circularly polarized light component by laminating a 波長 wavelength retardation layer (hereinafter also referred to as λ / 4 retardation layer) on a linearly polarizing plate. . For example, by converting external light into right-handed circularly polarized light, the external light reflected by the organic EL panel and turned into left-handed circularly polarized light is blocked, and only the luminescent component of the organic EL is transmitted, thereby suppressing the influence of the reflected light to reduce the image. Used to make it easier to see. In order to achieve the circular polarization function, the absorption axis of the linear polarizer or linear polarizer and the slow axis of the λ / 4 retardation layer need to be 45 ° in theory, but practically 45 ± 10 ° °. The linear polarizer or linear polarizer and the λ / 4 retardation layer need not necessarily be laminated adjacent to each other, as long as the relationship between the absorption axis and the slow axis satisfies the above range. It is preferable to achieve perfect circularly polarized light at all wavelengths, but this is not always necessary in practical use. Therefore, the circularly polarizing plate in the present invention includes an elliptically polarizing plate. It is also preferable that a λ / 4 retardation film is further laminated on the viewing side of the linear polarizer or the linear polarizing plate to make the outgoing light circularly polarized so as to improve the visibility under polarized sunglasses.

  The linear polarizing plate is a functional layer having a function of transmitting light vibrating in the transmission axis direction, but blocking polarization of a vibration component perpendicular to the light. The linear polarizing plate may be configured to include a linear polarizer alone or a linear polarizer and a protective film attached to at least one surface thereof. The thickness of the linear polarizing plate may be 200 μm or less, preferably 0.5 μm or more and 100 μm or less. If the thickness exceeds 200 μm, the flexibility may be reduced.

  The linear polarizer may be a film-type polarizer manufactured by dyeing and stretching a polyvinyl alcohol (PVA) -based film. A dichroic dye such as iodine is adsorbed on a PVA-based film oriented by stretching or stretched in a state of being adsorbed on PVA, whereby the dichroic dye is oriented to exhibit polarizing performance. In the production of the film-type polarizer, other steps such as swelling, crosslinking with boric acid, washing with an aqueous solution, and drying may be included. The stretching and dyeing steps may be performed on the PVA-based film alone, or may be performed on a laminate with another film such as polyethylene terephthalate. The PVA-based film used is preferably 10 μm or more and 100 μm or less, and the stretching ratio is preferably 2 to 10 times.

  Further, another example of the linear polarizer may be a liquid crystal application type polarizer formed by applying a liquid crystal polarization composition. The liquid crystal polarizing composition can include a liquid crystalline compound and a dichroic dye compound. The liquid crystal compound only needs to have a property of exhibiting a liquid crystal state, and it is particularly preferable that the compound has a high-order alignment state such as a smectic phase because high polarization performance can be exhibited. It is also preferred that the polymer has a polymerizable functional group. The dichroic dye compound is a dye that exhibits dichroism when aligned with the liquid crystal compound, and the dichroic dye itself may have liquid crystallinity or may have a polymerizable functional group. You can also. Any of the compounds in the liquid crystal polarizing composition has a polymerizable functional group. The liquid crystal polarizing composition may further include an initiator, a solvent, a dispersant, a leveling agent, a stabilizer, a surfactant, a crosslinking agent, a silane coupling agent, and the like. The liquid crystal polarizing layer can be manufactured by applying a liquid crystal polarizing composition on an alignment film to form a liquid crystal polarizing layer. The liquid crystal polarizing layer can be formed thinner than a film polarizer. The thickness of the liquid crystal polarizing layer may be 0.5 μm or more and 10 μm or less, preferably 1 μm or more and 5 μm or less.

  The alignment film can be produced, for example, by applying an alignment film forming composition on a substrate and imparting the alignment by rubbing, irradiation of polarized light, or the like. The alignment film forming composition may contain a solvent, a crosslinking agent, an initiator, a dispersant, a leveling agent, a silane coupling agent, and the like, in addition to the alignment agent. As the alignment agent, for example, polyvinyl alcohols, polyacrylates, polyamic acids, and polyimides can be used. When photo alignment is applied, it is preferable to use an alignment agent containing a cinnamate group. The polymer used as the alignment agent may have a weight average molecular weight of about 10,000 to 1,000,000. The orientation film preferably has a thickness of 5 nm or more and 10000 nm or less, and particularly preferably 10 nm or more and 500 nm or less, since the orientation regulating force is sufficiently exhibited. The liquid crystal polarizing layer can be peeled off from the substrate and transferred and laminated, or the substrate can be laminated as it is. It is also preferable that the base material plays a role as a transparent base material for the protective film, the retardation plate, and the window.

  The protective film only needs to be a transparent polymer film, and materials and additives used for the transparent substrate can be used. Cellulose-based films, olefin-based films, acrylic films, and polyester-based films are preferred. It may be a coating type protective film obtained by applying and curing a cationic curing composition such as an epoxy resin or a radical curing composition such as an acrylate. If necessary, plasticizers, ultraviolet absorbers, infrared absorbers, coloring agents such as pigments and dyes, fluorescent brighteners, dispersants, heat stabilizers, light stabilizers, antistatic agents, antioxidants, lubricants, solvents, etc. May be included. The thickness of the protective film may be 200 μm or less, preferably 1 μm or more and 100 μm or less. If the thickness exceeds 200 μm, the flexibility may be reduced. It can also serve as a transparent substrate for the window.

  The λ / 4 retardation layer may be the optical film of the present invention, or may be a film that gives a λ / 4 retardation in a direction (in-plane direction of the film) orthogonal to the traveling direction of incident light. . The film giving a phase difference of λ / 4 may be a stretched retardation plate manufactured by stretching a polymer film such as a cellulose film, an olefin film, and a polycarbonate film. If necessary, retarder, plasticizer, ultraviolet absorber, infrared absorber, colorant such as pigment or dye, optical brightener, dispersant, heat stabilizer, light stabilizer, antistatic agent, antioxidant , A lubricant, a solvent, and the like. The thickness of the stretching type retardation plate may be 200 μm or less, preferably 1 μm or more and 100 μm or less. If the thickness exceeds 200 μm, the flexibility may be reduced. The λ / 4 retardation layer is preferably the optical film of the present invention from the viewpoint of processability and flexibility.

  Further, another example of the λ / 4 retardation layer may be a liquid crystal-coated retardation plate formed by applying a liquid crystal composition. The liquid crystal composition includes a liquid crystal compound having a property of exhibiting a liquid crystal state such as nematic, cholesteric, or smectic. Any compound including a liquid crystal compound in the liquid crystal composition has a polymerizable functional group. The liquid crystal coating type retarder may further include an initiator, a solvent, a dispersant, a leveling agent, a stabilizer, a surfactant, a crosslinking agent, a silane coupling agent, and the like. The liquid crystal coating type retardation plate can be manufactured by coating and curing a liquid crystal composition on an alignment film to form a liquid crystal retardation layer in the same manner as described for the liquid crystal polarizing layer. The liquid crystal coating type retarder can be formed to be thinner than the stretch type retarder. The thickness of the liquid crystal polarizing layer may be 0.5 μm or more and 10 μm or less, preferably 1 μm or more and 5 μm or less. The liquid crystal-coated retardation plate can be peeled off from the substrate and transferred and laminated, or the substrate can be laminated as it is. It is also preferable that the base material plays a role as a transparent base material for the protective film, the retardation plate, and the window.

  In general, there are many materials exhibiting a large birefringence at a short wavelength and a small birefringence at a long wavelength. In this case, since a phase difference of λ / 4 cannot be achieved in the entire visible light region, an in-plane phase difference of 100 nm or more and 180 nm or less, preferably λ / 4 near 560 nm with high visibility, is preferable. It is often designed to be 130 nm or more and 150 nm or less. It is preferable to use an inverse dispersion λ / 4 retardation layer using a material having a birefringence wavelength dispersion characteristic opposite to that of a normal one because visibility can be improved. As such a material, it is also preferable to use those described in JP-A-2007-232873 and the like in the case of a stretched retardation plate and JP-A-2010-30979 in the case of a liquid crystal coating type retardation plate. .

  Further, as another method, there is known a technique of obtaining a broadband λ / 4 phase difference layer by combining with a 波長 wavelength phase difference layer (hereinafter, also referred to as λ / 2 phase difference layer) (Japanese Patent Laid-Open No. No. 90521). The λ / 2 retardation layer may be the optical film of the present invention, or may be manufactured using the same material and method as the λ / 4 retardation layer. The combination of the stretching type retardation plate and the liquid crystal coating type retardation plate is arbitrary, but it is preferable to use the liquid crystal coating type retardation plate because both can reduce the film thickness. The λ / 2 retardation layer is preferably the optical film of the present invention from the viewpoint of processability and flexibility.

  A method of laminating a positive C plate on a circularly polarizing plate in order to enhance visibility in an oblique direction is also known (JP-A-2014-224837). The positive C plate may be the optical film of the present invention, or may be a liquid crystal-coated retardation plate or a stretched retardation plate. The retardation in the thickness direction may be, for example, −200 nm or more and −20 nm or less, and preferably −140 nm or more and 40 nm or less. The positive C plate is preferably the optical film of the present invention from the viewpoint of workability and flexibility of the polarizing plate. The positive C plate can also be used as a retardation laminate in combination with a λ / 4 retardation layer.

(Touch sensor)
The touch sensor is used as an input unit. Various types of touch sensors have been proposed, such as a resistive film type, a surface acoustic wave type, an infrared type, an electromagnetic induction type, and a capacitance type, and any type may be used. Among them, the capacitance type is preferable. The capacitive touch sensor is divided into an active area and a non-active area located outside the active area. The active area is an area corresponding to an area (display unit) where a screen is displayed on the display panel, and is an area where a user's touch is sensed, and the inactive area is an area where the screen is not displayed on the image display device ( (A non-display portion). The touch sensor includes a substrate having flexible characteristics; a sensing pattern formed on an active region of the substrate; and a sensing pattern formed on an inactive region of the substrate and connected to an external driving circuit through the sensing pattern and a pad unit. A sensing line may be included. As the substrate having the flexible characteristics, the same material as the above-mentioned transparent substrate of the window can be used. The substrate of the touch sensor preferably has a toughness of 2,000 MPa% or more from the viewpoint of suppressing cracks in the touch sensor. More preferably, the toughness may be from 2,000 MPa% to 30,000 MPa%.

  The sensing pattern may include a first pattern formed in a first direction and a second pattern formed in a second direction. The first pattern and the second pattern are arranged in different directions. The first pattern and the second pattern are formed on the same layer, and must be electrically connected to each other in order to detect a touched point. The first pattern is a form in which each unit pattern is connected to each other via a joint, whereas the second pattern is a structure in which each unit pattern is separated from each other in an island form. A separate bridge electrode is required for connection. As the sensing pattern, a known transparent electrode material can be applied. For example, indium tin oxide (ITO), indium zinc oxide (IZO), zinc oxide (ZnO), indium zinc tin oxide (IZTO), cadmium tin oxide (CTO), PEDOT (poly (3,4- (ethylenedioxythiophene)), carbon nanotube (CNT), graphene, metal wire, etc., and these can be used alone or in combination of two or more. Preferably, ITO can be used. The metal used for the metal wire is not particularly limited, and examples thereof include silver, gold, aluminum, copper, iron, nickel, titanium, terenium, and chromium. These can be used alone or in combination of two or more.

  The bridge electrode may be formed on the insulating layer above the sensing pattern with an insulating layer interposed therebetween. The bridge electrode is formed on the substrate, and the insulating layer and the sensing pattern may be formed thereon. The bridge electrode may be formed of the same material as the sensing pattern, and may be formed of a metal such as molybdenum, silver, aluminum, copper, palladium, gold, platinum, zinc, tin, titanium, or an alloy of two or more of these. You can also. Since the first and second patterns must be electrically insulated, an insulating layer is formed between the sensing pattern and the bridge electrode. The insulating layer may be formed only between the joint of the first pattern and the bridge electrode, or may be formed in a layer structure covering the sensing pattern. In the latter case, the bridge electrode can connect the second pattern through a contact hole formed in the insulating layer. The touch sensor has a difference in transmittance between a pattern region in which a pattern is formed and a non-pattern region in which no pattern is formed, specifically, a difference in light transmittance induced by a difference in refractive index in these regions. As a means for appropriately compensating the above, an optical adjustment layer may be further included between the substrate and the electrode, and the optical adjustment layer may include an inorganic insulating material or an organic insulating material. The optical control layer can be formed by coating a photocurable composition containing a photocurable organic binder and a solvent on a substrate. The photocurable composition can further include inorganic particles. The refractive index of the optical adjustment layer can be increased by the inorganic particles.

  The photocurable organic binder can include, for example, a copolymer of each monomer such as an acrylate monomer, a styrene monomer, and a carboxylic acid monomer. The photocurable organic binder may be, for example, a copolymer containing different repeating units such as an epoxy group-containing repeating unit, an acrylate repeating unit, and a carboxylic acid repeating unit. The inorganic particles can include, for example, zirconia particles, titania particles, alumina particles, and the like. The photocurable composition may further include additives such as a photopolymerization initiator, a polymerizable monomer, and a curing aid.

(Adhesive layer)
Each layer (a window, a circularly polarizing plate, a touch sensor) and a film member (a linearly polarizing plate, a λ / 4 retardation plate, etc.) constituting each layer can be formed by an adhesive. Adhesives include water-based adhesives, organic solvent-based adhesives, solventless adhesives, solid adhesives, solvent volatile adhesives, moisture-curable adhesives, heat-curable adhesives, anaerobic-curable adhesives, and active energy ray-curable adhesives. General-purpose adhesives such as adhesives, hardener-mixed adhesives, hot-melt adhesives, pressure-sensitive adhesives (adhesives), and rewetting adhesives can be used. Among them, aqueous solvent volatile adhesives, active energy ray-curable adhesives, and pressure-sensitive adhesives are often used. The thickness of the adhesive layer can be appropriately adjusted according to the required adhesive strength and the like, and is 0.01 μm or more and 500 μm or less, preferably 0.1 μm or more and 300 μm or less. May be the same or different.

  As the aqueous-based solvent-evaporating adhesive, a water-soluble polymer such as a polyvinyl alcohol-based polymer or a starch, a polymer in an aqueous dispersion state such as an ethylene-vinyl acetate-based emulsion or a styrene-butadiene-based emulsion can be used as a main polymer. In addition to water and the main polymer, a crosslinking agent, a silane compound, an ionic compound, a crosslinking catalyst, an antioxidant, a dye, a pigment, an inorganic filler, an organic solvent, and the like may be blended. In the case of bonding with an aqueous-based solvent-evaporating adhesive, the adhesiveness can be imparted by injecting the aqueous-based solvent-evaporating adhesive between the layers to be adhered, bonding the adhered layer, and then drying. The thickness of the adhesive layer in the case of using the aqueous solvent-evaporating adhesive may be 0.01 μm or more and 10 μm or less, preferably 0.1 μm or more and 1 μm or less. When using a plurality of layers of the aqueous solvent-based volatile solvent, the thickness of each layer may be the same or different.

  The active energy ray-curable adhesive can be formed by curing an active energy ray-curable composition containing a reactive material that forms an adhesive layer by irradiating an active energy ray. The active energy ray-curable composition can contain at least one polymer of the same radical polymerizable compound and cationic polymerizable compound as the hard coat composition. The radical polymerizable compound is the same as the hard coat composition, and the same kind as the hard coat composition can be used. As the radically polymerizable compound used for the adhesive layer, a compound having an acryloyl group is preferable. It is also preferable to include a monofunctional compound in order to reduce the viscosity of the adhesive composition.

  The cationic polymerizable compound is the same as the hard coat composition, and the same kind as the hard coat composition can be used. As the cationically polymerizable compound used in the active energy ray-curable composition, an epoxy compound is particularly preferred. It is also preferable to include a monofunctional compound as a reactive diluent in order to reduce the viscosity of the adhesive composition.

  The active energy ray composition may further include a polymerization initiator. Examples of the polymerization initiator include a radical polymerization initiator, a cationic polymerization initiator, a radical and cationic polymerization initiator, and the like can be appropriately selected and used. These polymerization initiators are decomposed by at least one of active energy ray irradiation and heating to generate radicals or cations, thereby promoting radical polymerization and cationic polymerization. In the description of the hard coat composition, an initiator capable of initiating at least one of radical polymerization and cationic polymerization by irradiation with active energy rays can be used.

  The active energy ray-curable composition further contains an ion scavenger, an antioxidant, a chain transfer agent, an adhesion promoter, a thermoplastic resin, a filler, a flow viscosity modifier, a plasticizer, a defoamer solvent, an additive, and a solvent. Can be included. When bonding with an active energy ray-curable adhesive, the active energy ray-curable composition is applied to one or both of the layers to be adhered and then bonded, and the active energy ray is passed through either one or both of the layers. Irradiation and curing allow bonding. When an active energy ray-curable adhesive is used, the thickness of the adhesive layer may be 0.01 μm or more and 20 μm or less, preferably 0.1 μm or more and 10 μm or less. When a plurality of layers of the active energy ray-curable adhesive are used, the thickness of each layer may be the same or different.

  The pressure-sensitive adhesive is classified into an acrylic pressure-sensitive adhesive, a urethane-based pressure-sensitive adhesive, a rubber-based pressure-sensitive adhesive, a silicone-based pressure-sensitive adhesive and the like, depending on the base polymer, and any of them can be used. The pressure-sensitive adhesive may contain a crosslinking agent, a silane compound, an ionic compound, a cross-linking catalyst, an antioxidant, a tackifier, a plasticizer, a dye, a pigment, an inorganic filler, and the like, in addition to the base polymer. The components constituting the pressure-sensitive adhesive are dissolved and dispersed in a solvent to obtain a pressure-sensitive adhesive composition, and the pressure-sensitive adhesive composition is applied to a substrate and then dried to form a pressure-sensitive adhesive layer adhesive layer. The pressure-sensitive adhesive layer may be directly formed, or a layer separately formed on a substrate may be transferred. It is also preferable to use a release film to cover the adhesive surface before bonding. When an active energy ray-curable adhesive is used, the thickness of the adhesive layer may be 0.1 μm or more and 500 μm or less, preferably 1 μm or more and 300 μm or less. When a plurality of pressure-sensitive adhesives are used, the thickness of each layer may be the same or different.

(Shading pattern)
The light-shielding pattern can be applied as at least a part of a bezel or a housing of the flexible image display device. The visibility of the image is improved by hiding the wiring arranged on the peripheral portion of the flexible image display device by the light-shielding pattern so that the wiring is difficult to see. The light-shielding pattern may be in the form of a single layer or multiple layers. The color of the light-shielding pattern is not particularly limited, and has various colors such as black, white, and metal. The light-shielding pattern can be formed of a pigment for realizing a color and a polymer such as an acrylic resin, an ester resin, an epoxy resin, polyurethane, or silicone. These can be used alone or in a mixture of two or more. The light-shielding pattern can be formed by various methods such as printing, lithography, and inkjet. The thickness of the light-shielding pattern may be 1 μm or more and 100 μm or less, preferably 2 μm or more and 50 μm or less. It is also preferable to provide a shape such as inclination in the thickness direction of the optical pattern.

  FIG. 4 is a schematic cross-sectional view according to one embodiment of the flexible image display device. A circularly polarizing plate 100 shown in FIG. 4 includes a front plate 101, a circularly polarizing plate 102, a touch sensor 103, and an organic EL display panel 104 in this order.

  Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples. "%" And "parts" in the examples are% by mass and parts by mass unless otherwise specified. Various measurements and evaluations were performed as follows.

[Number of defects in optically anisotropic layer]
<Confirmation of defects>
The obtained optical film was cut into 50 mm × 50 mm, and the actual size and number of alignment defects on the screen were confirmed using an optical microscope (ECLIPSE ME600, manufactured by Nikon Corporation). For observation, a linear polarizing plate is inserted below the stage of the optical microscope. Next, the direction of the slow axis of the obtained optical film is made to coincide with the direction of the absorption axis of the linear polarizing plate inserted below the stage. Further, the polarizer of the optical microscope was rotated to be in a crossed Nicols state, and the area which became a luminescent spot was defined as an alignment defect. The actual size of the alignment defect was measured by measuring the length of the portion where the size of the defect region visually recognized when the region was depolarized and observed was maximized. As a result of observation, all defects were attributable to crystals of the polymerizable liquid crystal compound. Table 2 shows the results. The actual defect size shown in Table 2 is an average value of the measured actual sizes. All of the cut optical films had defects having an actual size of more than 50 μm at 6 defects / mm ² or less.

<ECLIPSE observation setting>
Light illuminance: Fully open Stage lower aperture: 0.5
Exposure time: 200ms
GAIN: 2.00
AWB: Not set

[Defect rate of optically anisotropic layer]
After measuring the number of defects described above, one visual field image (including defect portions) of the optical microscope in a crossed Nicols state was placed on a personal computer such that the portion between the brightest portion and the darkest portion had 256 gradations. The captured image was binarized using image processing software attached to a personal computer under the condition of a threshold 127, the area of the alignment defect was determined, and the defect rate was calculated. Table 2 shows the results.

[Measurement of piercing strength]
The piercing test uses a handy compression tester “KES-G5 needle penetration force measurement specification” manufactured by Kato Tech Co., Ltd. equipped with a needle having a spherical tip (tip diameter 1 mmφ, 0.5 R), and a temperature of 23 ± 3 ° C. Under the measurement conditions of a puncture speed of 0.0033 cm / sec. The piercing strength measured in the piercing test was determined by performing a piercing test on three test pieces and taking the average value. Table 2 shows the results.

[Measurement of tensile stress]
The tensile test was performed using a precision universal tester “Autograph AG-IS” manufactured by Shimadzu Corporation under the environment of a temperature of 23 ± 3 ° C. and a tensile speed of 1 mm / min. The size of the optical film used for the evaluation was 10 × 10 mm. A tensile test was performed in the slow axis direction of the optical film or in a direction perpendicular to the slow axis direction (that is, in the fast axis direction). The tensile stress measured in the tensile test was determined by performing a tensile test on three test pieces and setting the average value. Table 2 shows the results.

重合性液晶化合物（Ｂ−１）：

重合性液晶化合物（Ｃ−１）：

[Liquid crystal composition solution]
A polymerizable liquid crystal compound (A-1) (molecular weight 1156), a polymerizable liquid crystal compound (B-1) (molecular weight 664) and a polymerizable liquid crystal compound (C-1) (molecular weight 1083) represented by the following formulas were prepared.
Polymerizable liquid crystal compound (A-1):

Polymerizable liquid crystal compound (B-1):

Polymerizable liquid crystal compound (C-1):

  The polymerizable liquid crystal compound (A-1) was synthesized by the method described in JP-A-2011-207765.

  Polymerizable compound (B-1) was synthesized by the method described in JP-A-2010-24438.

  The polymerizable compound (C-1) was synthesized by the method described in JP-A-2010-24438.

  83 parts by weight of the obtained polymerizable liquid crystal compound (A-1), 3 parts by weight of the polymerizable liquid crystal compound (B-1), and 14 parts by weight of the polymerizable liquid crystal compound (C-1) were mixed to form a liquid crystal mixture (1). (Total amount of 100 parts by mass) was obtained.

  Referring to Patent Document (JP-A-2017-179367), a liquid crystal mixture (1), a polymerization initiator, a leveling agent, a polymerization inhibitor and a solvent were charged according to the composition shown in Table 1 to prepare a liquid crystal composition solution (1). Prepared. The amounts of the polymerization initiator, the leveling agent, and the polymerization inhibitor shown in Table 1 are amounts charged to 100 parts by mass of the liquid crystal mixture (1). The amount of the solvent was set so that the mass% of the liquid crystal mixture (1) was 10 mass% with respect to the total amount of the liquid crystal composition solution. (1) The solvent was added so as to contain 100 parts by mass].

Polymerization initiator: 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) butan-1-one (Irgacure 369; manufactured by BASF Japan)
Leveling agent: polyacrylate compound (BYK-361N; manufactured by BYK Japan)
Polymerization inhibitor: BHT (manufactured by Wako Pure Chemical Industries, Ltd.)
Solvent: N-methylpyrrolidone (NMP; manufactured by Kanto Chemical Co., Ltd.)

溶剤（９５部）：シクロペンタノン [Composition for forming photo-alignment film]
The following components were mixed, and the obtained mixture was stirred at 80 ° C. for 1 hour to obtain a composition (1) for forming a photo-alignment film. The photo-alignable material represented by the following formula was synthesized by the method described in JP-A-2013-33248.
Photo-alignment material (5 parts):

Solvent (95 parts): cyclopentanone

[Example 1]
An optical film was manufactured as follows. A cycloolefin polymer film (COP) (ZF-14, manufactured by Zeon Corporation, thickness 23 μm, heat capacity per substrate 1 cm ² is 0.004 J / cm ² · ° C.) is supplied to a corona treatment device (AGF-B10, Kasuga Electric) (Manufactured by K.K.) under the conditions of an output of 0.3 kW and a processing speed of 3 m / min. The composition (1) for forming a photo-alignment film was coated on the surface subjected to the corona treatment with a bar coater, dried at 80 ° C. for 1 minute, and polarized UV irradiation apparatus (SPOT CURE SP-7; manufactured by Ushio Inc.) Was used to perform polarized UV exposure at an integrated light amount of 100 mJ / cm ² . The thickness of the obtained alignment film was measured with a laser microscope (LEXT, manufactured by Olympus Corporation) and found to be 100 nm.

Subsequently, the prepared liquid crystal composition solution (1) was passed through a PTFE membrane filter (manufactured by Advantech Toyo Co., Ltd., product number: T300A025A) having a pore size of 0.2 μm under an environment of room temperature of 25 ° C. and humidity of 30% RH to obtain a liquid crystal composition solution (1). The obtained liquid crystal composition solution (1) was applied on a substrate with an alignment film kept at 25 ° C. using a bar coater, dried at 120 ° C. for 1 minute, and then subjected to a high-pressure mercury lamp (Unicur VB-15201BY-A, An optical film was prepared by irradiating ultraviolet rays (in a nitrogen atmosphere, wavelength: 365 nm, integrated light quantity at a wavelength of 365 nm: 1000 mJ / cm ² ) using Ushio Electric Co., Ltd.). When the thickness of the obtained coating film was measured with a laser microscope (LEXT, manufactured by Olympus Corporation), it was 2 μm.

[Example 2]
An optical film was prepared in the same manner as in Example 1, except that the substrate with the alignment film was coated while keeping the temperature at 40 ° C.

[Example 3]
An optical film was prepared in the same manner as in Example 1 except that the obtained substrate with an alignment film was heated at 80 ° C. for 10 seconds before coating, and then applied.

[Example 4]
The procedure was performed in the same manner as in Example 1 except that the composition ratio of the polymerizable liquid crystal compound was 82 parts by mass for (A-1), 4 parts by mass for (B-1), and 14 parts by mass for (C-1). An optical film was made.

[Example 5]
The procedure was performed in the same manner as in Example 1 except that the composition ratio of the polymerizable liquid crystal compound was changed to 77 parts by mass for (A-1), 9 parts by mass for (B-1), and 14 parts by mass for (C-1). An optical film was made.

[Example 6]
As a substrate, a soda glass plate having a thickness of 0.3 mm was bonded to an uncoated surface of COP (a surface on which the liquid crystal composition solution was not coated) with an adhesive. This base material had a heat capacity of 0.05 J / cm ² · ° C. per 1 cm ² of the base material. An optical film was produced in the same manner as in Example 1 except that this substrate was used.

[Comparative Example 1]
An optical film was prepared in the same manner as in Example 1 except that the humidity at the time of coating was set to 65% RH.

[Comparative Example 2]
Except that the composition ratio of the polymerizable liquid crystal compound was 99 parts by mass for (A-1), 1 part by mass for (B-1), and 0 part by mass for (C-1), the same procedure as in Example 1 was carried out. An optical film was made.

[Comparative Example 3]
The procedure was performed in the same manner as in Example 1 except that the composition ratio of the polymerizable liquid crystal compound was changed to 92 parts by mass for (A-1), 3 parts by mass for (B-1), and 5 parts by mass for (C-1). An optical film was made.

[Comparative Example 4]
As a base material, a soda glass plate having a thickness of 10 mm was bonded to an uncoated surface of COP with an adhesive. This substrate had a heat capacity of 1.68 J / cm ² · ° C. per 1 cm ^{2 of the} substrate. An optical film was produced in the same manner as in Example 1 except that this substrate was used.

[Retardation laminate]
<Production of First Retardation Layer>
Examples 1, 4, and 5 and Comparative Examples 2 and 3 were used as the first retardation layer.

<Production of second retardation layer>
A 38 μm-thick PET substrate was used as a transparent substrate, and one surface of the PET substrate was coated with a composition for a vertical alignment layer to a thickness of 3 μm, and irradiated with ultraviolet rays to prepare an alignment layer. In addition, as the composition for the vertical alignment layer, 2-phenoxyethyl acrylate, tetrahydrofurfuryl acrylate, dipentaerythritol triacrylate, and bis (2-vinyloxyethyl) ether were used in a ratio of 1: 1: 4: 5. And a mixture obtained by adding LUCIRIN TPO at a ratio of 4% as a polymerization initiator was used.

  Subsequently, a liquid crystal composition containing a photopolymerizable nematic liquid crystal (manufactured by Merck, RMM28B) was applied onto the alignment layer by die coating. Here, in the liquid crystal composition, as a solvent, methyl ethyl ketone (MEK), methyl isobutyl ketone (MIBK), and cyclohexanone (CHN) having a boiling point of 155 ° C. in a mass ratio (MEK: MIBK: CHN) of 35: A mixed solvent mixed at a ratio of 30:35 was used. Then, the liquid crystal composition prepared so as to have a solid content of 1 to 1.5 g was coated on the alignment layer so that the coating amount was 4 to 5 g (wet).

  Then, after applying the liquid crystal composition on the alignment layer, a drying treatment was performed at a drying temperature of 75 ° C. and a drying time of 120 seconds. Thereafter, polymerization was performed by irradiation of ultraviolet (UV) light to obtain a layer in which the photopolymerizable nematic liquid crystal compound was cured, an alignment layer, and a positive C layer including a transparent substrate. The total thickness of the cured layer of the photopolymerizable nematic liquid crystal compound and the alignment layer was 4 μm.

<Production of retardation laminate>
The first retardation layer and the second retardation layer were adhered to each other with an ultraviolet-curable adhesive such that the respective retardation layer surfaces (surfaces opposite to the transparent substrate) became the bonding surfaces. . Next, ultraviolet rays were irradiated to cure the ultraviolet curable adhesive. Thus, a retardation laminate (1) including two retardation layers, a first retardation layer and a second retardation layer, was produced.

[Polarizer]
A polyvinyl alcohol film having an average polymerization degree of about 2400 and a saponification degree of 99.9 mol% or more and a thickness of 30 μm is immersed in pure water at 30 ° C., and then the mass ratio of iodine: potassium iodide: water is 0.02: 2. : Iodine staining was carried out by immersion in an aqueous solution of 100 at 30 ° C (hereinafter also referred to as iodine staining step). The polyvinyl alcohol film having undergone the iodine dyeing step was immersed in an aqueous solution of potassium iodide: boric acid: water at a mass ratio of 12: 5: 100 at 56.5 ° C. to perform boric acid treatment (hereinafter, boric acid treatment). Process). The polyvinyl alcohol film having undergone the boric acid treatment step is washed with pure water at 8 ° C., and then dried at 65 ° C. to obtain a polarizer (12 μm thick after stretching) in which iodine is adsorbed and oriented in polyvinyl alcohol. . At this time, stretching was performed in the iodine dyeing step and the boric acid treatment step. The total stretching ratio in such stretching was 5.3 times.

  A saponified triacetyl cellulose film (KC4UYTAC 40 μm, manufactured by Konica Minolta Co., Ltd.) was bonded to both sides of the obtained polarizer with nip rolls via an aqueous adhesive. The obtained bonded product was dried at 60 ° C. for 2 minutes while keeping the tension of 430 N / m to obtain a polarizer (1) having a triacetyl cellulose film as a protective film on both surfaces. The water-based adhesive was used in 100 parts of water, 3 parts of a carboxy group-modified polyvinyl alcohol (Kuraray Co., Ltd. Kuraray Povar KL318) and 3 parts of a water-soluble polyamide epoxy resin (Sumireze Resin 650 manufactured by Taoka Chemical Industry Co., Ltd.). % Aqueous solution).

The optical characteristics of the obtained polarizer (1) were measured using a spectrophotometer (V7100, manufactured by JASCO Corporation). The obtained luminosity-corrected single transmittance was 42.1%, the luminosity-corrected polarization degree was 99.996%, the single hue a ^* was -1.1, and the single hue b ^* was 3.7.

[Polarizer]
The pressure-sensitive adhesive B was transferred to one side of the polarizer (1) as a first pressure-sensitive adhesive layer, the separate film was peeled off, and the transparent substrate on the first retardation layer side of the retardation laminate (1) was peeled off. Laminated on the surface. The pressure-sensitive adhesive F was laminated as a second pressure-sensitive adhesive layer on the surface of the retardation laminate (1) opposite to the surface laminated with the polarizer. Thus, the polarized light including the protective film, the polarizer, the protective film, the first pressure-sensitive adhesive layer, the first retardation layer, the adhesive layer, the second retardation layer, and the second pressure-sensitive adhesive layer in this order. A plate was made.

[Method of evaluating workability of polarizing plate]
When the obtained polarizing plate was cut into 100 mm x 100 mm by a super cutter, the cut end face was observed with an optical microscope, and three or more cracks in the retardation laminate were evaluated as x, 1-2. Those that were seen individually were marked with 、, and those that were not seen were marked with ◎. The crack lengths of the retardation laminates generated at this time were all 300 μm to 400 μm, and there was no difference in length.

[Polarizing plate with polyimide film]
The separate film of the second pressure-sensitive adhesive layer of the obtained polarizing plate was peeled off, and laminated on a 75 μm-thick polyimide film (Upilex S Model No. 75S, manufactured by Ube Industries). In this manner, the protective film, the polarizer, the protective film, the first pressure-sensitive adhesive layer, the first retardation layer, the adhesive layer, the second retardation layer, and the second pressure-sensitive adhesive layer, A polarizing plate with a polyimide film was sequentially prepared.

[Evaluation method of bending resistance of polarizing plate with polyimide film]
When the obtained polarizing plate with a polyimide film was cut into 100 mm × 10 mm by a super cutter and bent at 0.5 R so that the polyimide film became convex, five or more cracks were observed in the retardation laminate layer. X, 1 to 4 observed, and 〇 not observed. The length of the crack generated in Example 1 was 250 μm, and the length of the crack generated in Comparative Example 3 was 220 μm to 250 μm. There was no difference in the length of the crack between Example 1 and Comparative Example 3.

  Reference Signs List 10 optical film, 11 optically anisotropic layer, 12 alignment layer, 13 base layer, 20 retardation laminate, 31 first base layer, 32 first alignment layer, 33 first retardation layer, 34 Adhesive layer, 35 second retardation layer, 36 second alignment layer, 37 second base layer, 38 adhesive layer, 39 polarizer, 40 polarizing plate.

Claims (12)

An optical film having an optically anisotropic layer composed of a polymer obtained by polymerizing a polymerizable liquid crystal compound having one or more polymerizable functional groups in an oriented state,
An optical film, wherein the number of alignment defects whose actual size per 1 mm ^{2 of the} optically anisotropic layer is 0.3 μm or more and 50 μm or less satisfies the following expression (1).
0 ≦ number of alignment defects [pieces] ≦ 14 (1) An optical film having an optically anisotropic layer composed of a polymer obtained by polymerizing a polymerizable liquid crystal compound having one or more polymerizable functional groups in an oriented state,
An optical film, wherein the defect rate defined by the following formula (2) in the optically anisotropic layer satisfies the following formula (3).

[In the formula, the total defect area is the total area of the alignment defects having an actual size of 0.3 μm or more and 50 μm or less observed in one visual field of the optical microscope. This is the area of the optically anisotropic layer when the anisotropic layer is present]
0 ≦ defect rate [ppm] ≦ 1000 (3) An optical film having an optically anisotropic layer composed of a polymer obtained by polymerizing a polymerizable liquid crystal compound having one or more polymerizable functional groups in an oriented state,
The number of alignment defects whose actual size per 1 mm ^{2 of the} optically anisotropic layer is 0.3 μm or more and 50 μm or less satisfies the following expression (1), and the defect rate defined by the following expression (2) is An optical film characterized by satisfying 3).
0 ≦ number of alignment defects [pieces] ≦ 14 (1)

[In the formula, the total defect area is the total area of the alignment defects having an actual size of 0.3 μm or more and 50 μm or less observed in one visual field of the optical microscope. This is the area of the optically anisotropic layer when the anisotropic layer is present]
0 ≦ defect rate [ppm] ≦ 1000 (3)   The optical film according to claim 1, wherein the polymerizable functional group is an acryloyloxy group.   The optical film according to any one of claims 1 to 4, wherein the alignment defect includes a defect caused by microcrystals of a polymerizable liquid crystal compound.   The optical film according to claim 1, wherein a thickness of the optically anisotropic layer is 0.05 μm or more and 10 μm or less.   A retardation laminate comprising at least one optical film according to claim 1.   A polarizing plate comprising the retardation laminate according to claim 7.   The polarizing plate according to claim 8, which has a cut surface.   The polarizing plate according to claim 8, wherein the polarizing plate is a deformed polarizing plate.   The polarizing plate according to any one of claims 8 to 10, comprising at least one of a front plate and a touch sensor.   A flexible image display device comprising the polarizing plate according to claim 8.

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