JP2020118989A - 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 in a flat panel display device, for example, an optical liquid having an optically anisotropic layer obtained by applying a coating liquid obtained by dissolving a polymerizable liquid crystal compound in a solvent onto a supporting substrate and then polymerizing the coating liquid. A film has been proposed (Patent Document 1).

JP, 2011-207765, A

In recent years, with the thinning of optical films, it has been required to improve the film strength and workability of the optically anisotropic layer.

It is an object of the invention to provide an optical film with improved film strength. Another object of the present invention is to provide an optical film having improved processability 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 aligned state,
An optical film, wherein the number of alignment defects in which the actual size of the optically anisotropic layer per 1 mm ² is 0.3 μm or more and 50 μm or less satisfies the following formula (1).
0≦number of orientation defects [pieces]≦14 (1)
[2] 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 aligned 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 area of defects is 0.3 μm in the actual size observed in one field of the optical microscope.
It is the total of the areas of the alignment defects of 50 μm or less, and the microscope observation field is the area of the optically anisotropic layer when the optically anisotropic layer is present over the entire field of the optical microscope.
0 ≤ defect rate [ppm] ≤ 1000 (3)
[3] 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 aligned state,
The number of alignment defects in which the actual size of the optically anisotropic layer per 1 mm ² is 0.3 μm or more and 50 μm or less satisfies the following formula (1), and the defect rate defined by the following formula (2) is the following formula ( An optical film satisfying 3).
0≦number of orientation defects [pieces]≦14 (1)

[In the formula, the total area of defects is 0.3 μm in the actual size observed in one field of the optical microscope.
It is the total of the areas of the alignment defects of 50 μm or less, and the microscope observation field is the area of the optically anisotropic layer when the optically anisotropic layer is present over the entire field of the optical microscope.
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 fine crystals of the 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 including at least one optical film according to any one of [1] to [6].
[8] A polarizing plate including the retardation laminate according to [7].
[9] The polarizing plate according to [8], which has 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], which includes at least one of a front plate and a touch sensor.
[12] A flexible image display device including 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. Moreover, according to this invention, the optical film which has the improved workability can be provided.

It is a schematic sectional drawing which shows the optical film which concerns on 1 aspect of this invention. It is a schematic sectional drawing which shows the retardation laminated body which concerns on 1 aspect of this invention. It is a schematic sectional drawing which shows the polarizing plate which concerns on 1 aspect of this invention. It is a schematic sectional drawing which shows the flexible image display apparatus which concerns on 1 aspect of this invention.

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

The polymer polymerized in the aligned state of the polymerizable liquid crystal compound contained in the optically anisotropic layer is preferably a polymer polymerized in the aligned state in one direction. The alignment may be horizontal alignment in which the optical axis of the polymerizable liquid crystal compound is aligned horizontally with respect to the optical film plane, and is vertical alignment in which the optical axis of the polymerizable liquid crystal compound is aligned vertically with respect to the optical film plane. You can The optical axis means a direction in which, in an index ellipsoid formed by the alignment of the polymerizable liquid crystal compound, a cross section cut in a direction orthogonal to the optical axis becomes a circle, that is, a direction in which the refractive indices in the two directions are equal. ..

The optically anisotropic layer can exhibit an in-plane retardation by polymerizing in a state where the polymerizable liquid crystal compound is aligned in a suitable direction. When the polymerizable liquid crystal compound is rod-shaped, an in-plane retardation appears by orienting the optical axis of the polymerizable liquid crystal compound horizontally to the optical film plane. In this case, the optical axis direction and the slow axis direction Matches with. When the polymerizable liquid crystal compound is disk-shaped, an in-plane retardation is exhibited 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 Are orthogonal. The alignment state of the polymerizable liquid crystal compound can be adjusted by a combination of an alignment film, which will be described later, and the polymerizable liquid crystal compound.

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 long 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 involved in the polymerization reaction, and is preferably a photopolymerizable group. Here, the photopolymerizable group refers to a group that can participate in the polymerization reaction by an active radical or an acid generated from a photopolymerization initiator described later. 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 crystallinity of the polymerizable liquid crystal compound may be a thermotropic liquid crystal or a lyotropic liquid crystal, and when 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 with respect to 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 with respect to one polymerizable functional group, good liquid crystallinity tends to be easily obtained. The molecular weight of one polymerizable functional group of the polymerizable liquid crystal compound is preferably 280 or more, more preferably 300 or more, and usually 1000 or less.

The molecular weight of the polymerizable liquid crystal compound is preferably 500 or more, more preferably 560 or more, still more preferably 600 or more, and usually 2000 or less. The smaller the molecular weight of the polymerizable liquid crystal compound, the more it tends to crystallize. Therefore, it is preferable to use a polymerizable liquid crystal compound having a small molecular weight from the viewpoint of reducing specific defects caused by microcrystals. On the other hand, the larger the molecular weight of the polymerizable liquid crystal compound, the easier the crystallization is, and the more the orientation defects due to the crystallization tend to be. When a polymerizable liquid crystal compound having a relatively large molecular weight, such as 500 or more, is used, two or more kinds of liquid crystal compounds are used as the polymerizable liquid crystal compound in order to bring the number of specific defects into the range defined by the present invention. Polymerization can be performed by using them in combination, and the humidity at the time of applying the polymerizable liquid crystal compound onto the substrate can be made 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, Liquid Crystal Handbook (edited by the Liquid Crystal Handbook Editorial Committee, published by Maruzen Co., Ltd., October 30, 2000) A compound having a polymerizable group among the compounds described in “3.8.6 Network (completely crosslinked)” and “6.5.1 Liquid crystal material b. Polymerizable nematic liquid crystal material” in JP 2011 -207765, JP-A-2010-24438, JP-A-2015-163937, JP-A-2017-179367, JP-A-2016-42185, International Publication No. 2016/158940, JP-A-2016-224128. The compounds exemplified in the publications and the like can be used. The optically anisotropic layer may include only one type of polymer of the polymerizable liquid crystal compound, or may include two or more types thereof.

In recent years, thinned optical films have been demanded, and thinned optical anisotropic layers containing a polymer of a polymerizable liquid crystal compound have also been demanded. However, the optically anisotropic layer in which the polymer of the polymerizable liquid crystal compound is oriented in one direction is very fragile and the film strength tends to be low. As a result of the present inventor's research on improvement of the film strength of an optical film, an optically anisotropic layer made of a polymerized product of a polymerizable liquid crystal compound in an aligned state was found to have film strength and processability and optical anisotropy. It has been found that there is a correlation with the number of orientation defects in the layer. Focusing on that, the present inventor has conducted further research and found that the smaller the number of the above-mentioned specific defects in the optically anisotropic layer, the more excellent the film strength of the optical film tends to be. It was determined that when the formula (1) is satisfied, the film strength and workability of the optically anisotropic layer tend to be improved. As a matter of course, it is ideal and desirable that the number of specific defects in the optical film is 0, but it is difficult to manufacture an optically anisotropic layer in which the number of specific defects is 0. Therefore, the optical film usually has a specific defect, and stress generated in the optical film when the optical film having the specific defect is used or processed is concentrated on the specific defect, and the optical film is cracked or torn. It is presumed that it will happen. Therefore, when the number of specific defects existing in the optically anisotropic layer made of an oriented polymer of a polymerizable liquid crystal compound having a specific molecular weight is small, the stress is less concentrated, and as a result, the optical film is It is considered that the film is less likely to be cracked or split and the workability of the optical film is improved.

The specific defect is a region in which the alignment failure of the polymerizable liquid crystal compound has occurred, and is observed as a bright spot under an optical microscope crossed Nicol state. Specific defects include fine crystals and gels of the polymerizable liquid crystal compound, foreign matter, cissing and unevenness of the coating film of the polymerizable liquid crystal compound, defective alignment film, unevenness and scratches on the substrate, and 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 having the maximum dimension in the outer shape of a defect visually observed when the bright spot is observed by releasing the crossed Nicols state of the optical microscope. For example, when the outer shape 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 outer shape of the defect is visually recognized as a quadrangle, the actual size is the length of the diagonal line of the quadrangle. When the actual size of the defect is less than 0.3 μm, it tends to be difficult to be observed as a bright spot under an optical microscope crossed Nicol state. When the actual size of the defect is more than 50 μm, the defect tends to be visually recognized, and the optical film tends to be unusable due to poor appearance. Defects whose actual size is 0.3 μm or more and 50 μm or less are not recognized as bright spots because the degree of polarization of the polarizing plate is lower than the current state and it tends to be difficult to be observed as a bright spot under an optical microscope crossed Nicol state. It is a thing. However, in recent years, reduction of such defects has been demanded from the viewpoint of further improving quality. It is ideal and desirable that the number of defects having an actual size of more than 50 μm is 0/mm ² , but they are present as long as they do not affect the appearance, film strength, and processability of the optical film. Well, it is usually 3/mm ² or less, and at most 5/mm ² or 6/mm ² . It should be noted that most of the defects having an actual size of more than 50 μm are caused by foreign matter.

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 to make the number of specific defects satisfy the formula (1), for example, the composition of the liquid crystal composition, which will be described later, which constitutes the optically anisotropic layer, the composition of the production conditions, or the combination thereof can be adjusted. ..

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 content concentration and the like in the liquid crystal composition can be adjusted.

The liquid crystal composition can preferably contain two or more kinds of 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 be easily precipitated. Therefore, when the mass ratio of the main polymerizable liquid crystal compound in the liquid crystal composition is lowered, the number of specific defects due to the 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 based on the total amount of the polymerizable liquid crystal compounds, and preferably 85%. It is not more than mass %. Microcrystals refer to crystals having a size of several nm to several hundreds μm, crystal grains, and aggregates thereof.

As described above, the larger the molecular weight of the polymerizable liquid crystal compound, the easier the crystallization is, and the more the specific defects due to the microcrystals tend to be. Therefore, when 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 is used, in order to keep the number of alignment defects within the range specified by the present invention, for example, the polymerizable liquid crystal compound is used. Polymerization can be performed by combining two or more kinds of liquid crystal compounds as compounds.

When the liquid crystal composition contains a sparingly soluble polymerizable liquid crystal compound, crystals of the sparingly soluble polymerizable liquid crystal compound tend to be easily deposited. Therefore, if 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 the microcrystals tends to decrease. When the liquid crystal composition contains a sparingly soluble polymerizable liquid crystal compound, the sparingly 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 in the liquid crystal composition is increased to lower the solid content, crystals of the polymerizable liquid crystal compound are less likely to precipitate, and the number of specific defects due to the microcrystals tends to decrease. Further, when the solid content is lowered by increasing the amount of the solvent, the solvent in the coating film is hard to completely volatilize, and thus the crystals of the polymerizable liquid crystal compound are hard to precipitate, and the number of specific defects caused by the microcrystals is small. 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 weight 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) is added to the liquid crystal composition, or the polymerizable liquid crystal compound is added. The number of specific defects due to fine crystals also tends to be reduced by making a part or all of the dimer, trimer or higher oligomer before orienting and polymerizing. When the liquid crystal composition contains a monomer or polymer other than the polymerizable liquid crystal compound, or a dimer, trimer or oligomer of the polymerizable liquid crystal compound, the solubility in a solvent is improved and the precipitation of crystals is suppressed. It tends to be easily done.

When the production conditions are adjusted, for example, the temperature of the base material when applying the liquid crystal composition, the humidity of the ambient atmosphere during coating, the ambient atmosphere of the die used for coating, and the like can be adjusted.

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

By using a substrate having a good surface smoothness, the coating uniformity of the polymerizable liquid crystal compound is increased, and the number of specific defects due to cissing or defective alignment film of the polymerizable liquid crystal compound tends to decrease. .. Examples of means for increasing the smoothness of the surface of the base material include annealing (repairing). The annealing can be performed by heating the substrate, and the heating temperature may be, for example, 60° C. or higher and 100° C. or lower, or 5° C. to 20° C. lower than the glass transition point of the substrate. The duration of time may be, for example, 1 second or more and 60 seconds or less.

By keeping the humidity of the ambient atmosphere during coating constant, it is easy to suppress crystallization of the polymerizable liquid crystal compound, and the number of specific defects due to microcrystals tends to decrease. The humidity of the ambient 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 ambient atmosphere during coating may be, for example, 10% RH or higher, and preferably 20% RH or higher. When a polymerizable liquid crystal compound having a relatively large molecular weight is used, in order to bring the number of specific defects into the range specified in the present invention, the humidity when the polymerizable liquid crystal compound is applied onto the substrate may be relatively low. 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 (in the solvent atmosphere), the solvent of the polymerizable liquid crystal compound becomes difficult to volatilize, and the crystal of the polymerizable liquid crystal compound is reduced. Formation is suppressed, and the number of specific defects due to microcrystals tends to decrease.

By removing contaminants on the surface of the base material, such as PET lubricant, PET oligomer, silicone oil, etc., before coating the liquid crystal composition, the number of specific defects due to foreign substances tends to decrease. In addition, the number of specific defects due to foreign substances tends to be reduced by applying the liquid crystal composition in a clean room having a high degree of cleanliness. Further, by removing foreign matters, fine crystals, etc. in the liquid crystal composition before coating with a filter, the number of specific defects caused by the fine crystals and the foreign matters tends to decrease.

The number of specific defects per 1 mm ^{2 of the} optically anisotropic layer is preferably 10 or less, more preferably 7 or less, further preferably 6 or less, particularly preferably 3 or less, and 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 due to microcrystals to the number of specific defects per 1 mm ^{2 of the} optically anisotropic layer may be, for example, 70% or more, or may be 85% or more, preferably 90% or more. Is. When it is caused by microcrystals, if microcrystals are present in the optically anisotropic layer, it is presumed that when stress is applied, the crystal part becomes a stress concentration point and is broken. Therefore, when 70% or more of the specific defects are due to the microcrystals, the number of the specific defects due to the microcrystals is 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 membrane strength will be stronger.

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

The ratio of the number of defects due to cissing 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 the puncture strength measurement method described in the section of Examples described later. The puncture strength of the optical film may be, for example, 5 gmm or more and 100 gmm or less, preferably 10 gmm or more and 80 gmm or less, more preferably 15 gmm or more.
It is not less than gmm and not more than 50 gmm. When the puncture strength of the optical film is within the above range, good film strength tends to be easily obtained even when the optical film is made thin.

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

The film strength of the optically anisotropic layer can also be evaluated according to the 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 made thin.

The optical film may further have a base material layer and an alignment layer in addition to the optically anisotropic layer.

The base material 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 or polypropylene; a cyclic polyolefin resin such as norbornene polymer. Polyester resins such as polyethylene terephthalate and polyethylene naphthalate; (meth)acrylic acid resins such as (meth)acrylic acid and poly(meth)acrylate; triacetyl cellulose, diacetyl cellulose, cellulose acetate propionate, etc. Cellulose ester resins; vinyl alcohol resins such as polyvinyl alcohol and polyvinyl acetate; polycarbonate resins; polystyrene resins; polyarylate resins; polysulfone resins; polyethersulfone resins; polyamide resins; polyimide resins; poly Examples thereof include ether ketone-based resins; polyphenylene sulfide-based resins; polyphenylene oxide-based resins, and mixtures and copolymers thereof. Of these resins, it is preferable to use any one of a cyclic polyolefin resin, a polyester resin, a cellulose ester resin and a (meth)acrylic acid 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 preferably 1 cm of the base material from the viewpoint that the temperature control of the optical film by an environmental temperature control device such as a drying furnace or a cooling furnace becomes easy. 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 indicates the heat capacity included in the volume contained when the base material layer is cut out by 1 cm ² .

The specific heat of the base material layer is not particularly limited, but from the same viewpoint, it 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 material layer and an alignment layer, in order to improve the adhesion between the base material layer and the alignment layer, the surface of the base material layer on the side where the alignment layer is formed, corona treatment, plasma treatment Flame treatment or the like may be performed, and a primer layer or the like may be formed.

The alignment layer has an alignment control 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 glob alignment layer having an uneven pattern or a plurality of grooves (grooves) on the layer surface. The thickness of the alignment layer is usually 10 nm or more and 4000 nm or less, and preferably 50 nm or more and 3000 nm or less.

The oriented polymer layer can be formed by applying a composition in which an oriented polymer is dissolved in a solvent to the substrate layer to remove the solvent, and performing a rubbing treatment if necessary. In this case, in the orientation polymer layer formed of the orientation polymer, the orientation control force can be arbitrarily adjusted depending on the surface state of the orientation polymer and rubbing conditions.

The photoalignable polymer layer is obtained by applying a composition containing a polymer or monomer having a photoreactive group and a solvent (hereinafter, also referred to as a photoalignment film forming composition) to a base material layer and irradiating it with light such as ultraviolet rays. Can be formed. In particular, when the alignment regulating force is exerted in the horizontal direction, it can be formed by irradiating polarized light. In this case, in the photoalignable polymer layer, the alignment regulating force can be arbitrarily adjusted by the polarized light irradiation condition or the like with respect to the photoalignable polymer.

The groove alignment layer is, for example, a method of forming an uneven pattern by performing exposure, development, etc. through an exposure mask having a patterned slit on the surface of a photosensitive polyimide film, a plate-shaped master having grooves on the surface, and active. A method of forming an uncured layer of an energy ray curable resin, transferring this layer to a base material layer and curing the same, forming an uncured layer of an active energy ray curable resin on the base material layer, and forming a uncured layer on this layer. Alternatively, it can be formed by a method of forming unevenness by pressing a roll-shaped master having unevenness, and then curing.

When the optical film includes a base material layer and an alignment layer, when the base material layer is peeled off, the alignment layer may be peeled off together with the base material layer, and the alignment layer remains on the optically anisotropic layer. Good. Whether the alignment layer is peeled off together with the base material layer or remains in the optically anisotropic layer can be set by adjusting the relationship of the adhesive force between the respective layers. For example, it is performed for the base material layer. It can be adjusted by the above-mentioned 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 aspect of the present invention is an optical film having an optically anisotropic layer made of a polymer polymerized in a state in which a polymerizable liquid crystal compound having one or more polymerizable functional groups is aligned. The defect rate defined by the following formula (2) in the optically anisotropic layer satisfies the following formula (3).

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

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

When the defect rate of the optically anisotropic layer satisfies the formula (3), the film strength and workability of the optically anisotropic layer tend to be good. The defect rate of the optically anisotropic layer is preferably 600 ppm or less, more preferably 300 ppm or less, still more preferably 100 ppm or less, and particularly preferably 50 ppm or less from the viewpoint of film strength and processability 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 satisfy the defect rate of the optically anisotropic layer to satisfy the formula (3), for example, selection of the type and molecular weight of the polymerizable liquid crystal compound, adjustment of the composition, adjustment of the production conditions, and combinations thereof may be performed. it can. A specific example of adjusting the type and molecular weight of the polymerizable liquid crystal compound, adjusting the composition, and adjusting the manufacturing conditions is that 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 above-mentioned optically anisotropic layer is What has been illustrated in order to satisfy the formula (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 aspect of the present invention is an optical film having an optically anisotropic layer containing a polymer polymerized in a state in which a polymerizable liquid crystal compound having one or more polymerizable functional groups is aligned. Then, 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 formula (1), and the defect rate defined by the following formula (2) is represented by the following formula (3). ) Is satisfied.
0≦number of orientation defects [pieces]≦14 (1)

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

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 formula (1) and the defect rate satisfies the formula (3), the film of the optically anisotropic layer. The strength and workability tend to be excellent.

The optical film is excellent in transparency and has a single layer or a laminated structure (for example, a structure of 2 layers or more and 4 layers or less) by itself, and can be used for various purposes together with a substrate and/or an alignment film or various optical films. it can. When laminating a plurality of layers, the same film may be used, or different films may be used in combination. Here, the optical film means a film that can transmit light and has an optical function, and the optical function means refraction, birefringence and the like.

As the optical film, for example, the first embodiment: a retardation film in which a rod-shaped liquid crystal compound is aligned in the horizontal direction with respect to a supporting substrate,
Second mode: 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 a rod-shaped liquid crystal compound has an in-plane helically changing orientation direction,
Fourth form: a retardation film in which a discotic liquid crystal compound is tilt-aligned,
Fifth form: 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, and 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 within 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 characteristic in which the liquid crystal alignment in-plane retardation value at the short wavelength is smaller than the liquid crystal alignment in-plane retardation value at the long wavelength, and preferably the optical film has the following formula ( i) and equation (ii) are satisfied. 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-mentioned first form and has the reverse wavelength dispersion property, it is preferable because the coloring at the time of black display in the display device is reduced, and 0.82≦Re(450)/Re( in the formula (1). It is more preferable that 550)≦0.93. Further, 120≦Re(550)≦150 is preferable.

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

The retardation value R _th in the thickness direction, which means the refractive index anisotropy in the thickness direction, is the retardation value R ₅₀ and the in-plane retardation value measured by inclining the in-plane fast axis by 50 degrees. It can be calculated from R _e . That is, the retardation value R _th in the thickness direction is the in-plane retardation value R _e , the retardation value R ₅₀ measured by inclining the fast axis as the tilt axis by 50 degrees, the thickness d of the retardation film, and the position. From the average refractive index n ₀ of the retardation film, n _x , _ny and _nz can be obtained by the following formulas (iv) to (vi), and these can be calculated by substituting them into the formula (iii).

_Rth =[( _nx + _ny )/2- _nz ]xd(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 VA (Vertical Alignment) mode, the thickness of the optical film may be adjusted by appropriately adjusting the content of the polymerizable liquid crystal compound in the liquid crystal composition. 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.

[Method for producing optical film]
The optical film can be produced, for example, by preparing a liquid crystal composition, then coating the liquid crystal composition on a base material or an alignment film, drying and polymerizing the polymerizable liquid crystal compound.

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

The larger the molecular weight of the polymerizable liquid crystal compound, the easier it is to crystallize, and the larger the number of specific defects due to microcrystals. In order to bring the content into the range specified in the invention, for example, two or more kinds of liquid crystal compounds may be combined as the polymerizable liquid crystal compound to carry out the polymerization.

(Polymerizable liquid crystal compound)
Examples of the polymerizable liquid crystal compound include JP2011-207765A, JP2010-24438A, JP2015-163937A, JP2017-179367A, JP2016-42185A, and international publication. Those exemplified in No. 2016/158940, JP-A No. 2016-224128 and the like can be used alone or in combination of two or more kinds. The polymerizable liquid crystal compound has one or more polymerizable functional groups, preferably two or more polymerizable functional groups, more preferably 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 of 250 or more with respect to 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 with respect to one polymerizable functional group, good liquid crystallinity tends to be easily obtained. The molecular weight of one polymerizable functional group of the polymerizable liquid crystal compound is preferably 280 or more, more preferably 300 or more, and usually 1000 or less.

The molecular weight of the polymerizable liquid crystal compound is preferably 500 or more, more preferably 560 or more, still more preferably 600 or more, and usually 2000 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) Having π electrons in the major axis direction (a) of the polymerizable liquid crystal compound.
(3) Having π electrons in a direction [intersection direction (b)] intersecting with the major axis direction (a).
(4) A polymerizable liquid crystal compound defined by the following formula (i), where N(πa) is the total of π electrons existing 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) of:
D(πa)=N(πa)/N(Aa) (i)
And a total of π electrons existing in the cross direction (b) is N(πb), and a total of molecular weights existing in the cross direction (b) is N(Ab), and the polymerizable liquid crystal compound is defined by the following formula (ii). Π 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 higher than the π electron density in the major axis direction (a)).
The polymerizable liquid crystal compound satisfying all of the above (1) to (4) can form a nematic phase by, for example, being applied on an alignment film and heated to a phase transition temperature or higher. In the nematic phase formed by aligning the polymerizable liquid crystal compound, the polymerizable liquid crystal compounds are usually aligned such that the major axis directions thereof are parallel to each other, and the major axis direction 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-mentioned properties generally exhibits reverse wavelength dispersion. Specific examples of the compound satisfying the above characteristics (1) to (4) include the following formula (I):

The compound represented by

In 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 cyclic structure, and the cyclic structure has a number of π electrons of [4n+2] according to Huckel's rule. Here, n represents an integer. In the case where a ring structure is formed by containing a hetero atom such as -N= or -S-, the case where the Huckel rule is satisfied including the non-covalent bond electron pair on these hetero atoms and the aromatic structure is also included. The divalent aromatic group preferably contains at least one or more 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, the 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, or a carbon atom. The carbon atom which may be substituted with an alkoxy group, a cyano group or a nitro group of the formulas 1 to 4 and which constitutes the divalent aromatic group or the divalent alicyclic hydrocarbon group is an oxygen atom or a sulfur atom. Alternatively, it may be substituted with 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 , and G ¹ and G ² may be the same or different from each other.
E ¹ and E ² each independently represent an alkanediyl group having 1 to 17 carbon atoms, in which the hydrogen atom contained in the alkanediyl group may be substituted with a halogen atom. The included —CH ₂ — may be substituted with —O—, —S—, and —Si—.
P ¹ and P ² independently of each other 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 which may be substituted with at least one substituent selected from the group consisting of a halogen atom and an alkyl group having 1 to 4 carbon atoms, more preferably 1 substituted with a methyl group. , 4-phenylenediyl group, an unsubstituted 1,4-phenylenediyl group, or an unsubstituted 1,4-trans-cyclohexanediyl group, particularly preferably an unsubstituted 1,4-phenylenediyl group, or an unsubstituted It is a substituted 1,4-trans-cyclohexanediyl group.
Further, at least one of a plurality of G ¹ and G ² present is preferably a divalent alicyclic hydrocarbon group, and at least 1 of G ¹ and G ² bonded to L ¹ or L ² More preferably, it is a divalent alicyclic hydrocarbon group.

L ¹ and L ² are each independently preferably a single bond, an alkylene group having 1 to 4 carbon atoms, —O—, —S—, —R ^a1 OR ^a2 —, —R ^a3 COOR ^a4 —, or —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 —. .. Here, R ^a2-1 , R ^a4-1 , and R ^a6-1 each independently represent a single bond, —CH ₂ —, or —CH ₂ CH ₂ —. 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 each independently preferably a single bond, an alkylene group having 1 to 4 carbon atoms, —O—, —S—, —R ^a9 OR ^a10 —, —R ^a11 COOR ^a12 —, or —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 more preferably a single bond, —OR ^a10-1- , —CH ₂ —, —CH ₂ CH ₂ —, ^{—COOR a12-1} —, or OCOR ^a14-1 —. .. Here, R ^a10-1 , R ^a12-1 , and R ^a14-1 each independently represent a single bond, —CH ₂ —, or —CH ₂ CH ₂ —. 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 —. ..

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

E ¹ and E ² are each independently preferably an alkanediyl group having 1 to 17 carbon atoms, and 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. Group, oxetanyl group and the like. 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 heterocycle 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. The aromatic heterocycle includes 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. , A thiazole ring, a benzothiazole ring, a thienothiazole ring, an oxazole ring, a benzoxazole ring, and a phenanthroline ring. Among them, a thiazole ring, a benzothiazole ring, or a benzofuran ring is preferable, and a benzothiazole group is more preferable. Further, 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, further 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 formulas (Ar-1) to (Ar-23), * represents a connecting part, and Z ⁰ , Z ¹ and Z ² are each independently a hydrogen atom, a halogen atom or an alkyl group having 1 to 12 carbon atoms. 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, Alkylthio group having 1 to 12 carbon atoms, N-alkylamino group having 1 to 12 carbon atoms, N,N-dialkylamino group having 2 to 12 carbon atoms, N-alkylsulfamoyl group having 1 to 12 carbon atoms or carbon It represents an N,N-dialkylsulfamoyl group of the number 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'> represents a hydrogen atom or a C1-C4 alkyl group each independently.

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, and a phenyl group. , A naphthyl group is preferable, and a phenyl group is more preferable. As the aromatic heterocyclic group, a furyl group, a pyrrolyl group, a thienyl group, a pyridinyl group, a thiazolyl group, a nitrogen atom such as a benzothiazolyl group, an oxygen atom, a C 4-20 carbon atom containing at least one hetero atom such as a sulfur atom Examples of the aromatic heterocyclic group include furyl group, thienyl group, pyridinyl group, thiazolyl group and benzothiazolyl group.

Y ¹ , Y ² and Y ³ may each independently be an optionally substituted polycyclic aromatic hydrocarbon group or polycyclic aromatic heterocyclic group. The polycyclic aromatic hydrocarbon group refers to a condensed polycyclic aromatic hydrocarbon group or a group derived from an aromatic ring assembly. The polycyclic aromatic heterocyclic group means a fused polycyclic aromatic heterocyclic group or a group derived from an aromatic ring assembly.

Z ⁰ , Z ¹ and Z ² are preferably 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, and Z ⁰ is more preferably a hydrogen atom, an alkyl group having 1 to 12 carbon atoms or a cyano group, and Z ¹ and Z ² are further preferably a hydrogen atom, a fluorine atom, a chlorine atom, a methyl group or a cyano group.

Each of Q ¹ , Q ² and Q ³ is preferably —NH—, —S—, —NR ^2′ — or —O—, and R ^2′ is preferably a hydrogen atom. Among them, -S-, -O-, and -NH- are particularly preferable.

Among formulas (Ar-1) to (Ar-23), formula (Ar-6) and formula (Ar-7) are preferable from the viewpoint of molecular stability.
In 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, and examples thereof include a pyrrole ring, an imidazole ring, a pyrroline ring, a pyridine ring, a pyrazine ring, a pyrimidine ring and an indole. Ring, quinoline ring, isoquinoline ring, purine ring, pyrrolidine ring and the like. This aromatic heterocyclic group may have a substituent. 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 . Examples thereof include a benzofuran ring, a benzothiazole ring, a benzoxazole ring and the like.

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 parts by mass or more and 98 parts by mass or less, still more preferably 80 parts by mass or more and 97 parts by mass or less. 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 kinds of 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 kinds of polymerizable liquid crystal compounds, the liquid crystal composition may contain, for example, 90% by mass or less of the main polymerizable liquid crystal compound, and preferably 85% by mass. Including:

From the viewpoint of improving the solubility in a solvent, the liquid crystal composition can preferably include a dimer, trimer or higher oligomer thereof together with the polymerizable liquid crystal compound. As a result, precipitation of fine crystals tends to be suppressed.

(solvent)
When the liquid crystal composition contains an organic solvent, it is possible to suppress the precipitation of crystals of the polymerizable liquid crystal compound contained in the liquid crystal composition, and thus 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 tend to be easy when forming an optical film. As the solvent, those capable of completely dissolving the polymerizable liquid crystal compound are preferable, and it is preferable that the solvent 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; toluene. And aromatic hydrocarbon solvents such as xylene, nitrile solvents such as acetonitrile; ether solvents such as tetrahydrofuran and dimethoxyethane; chlorine-containing solvents such as chloroform and chlorobenzene; dimethylacetamide, dimethylformamide, N-methyl-2-pyrrolidone, Examples thereof include amide solvents such as 1,3-dimethyl-2-imidazolidinone. These solvents may be used alone or in combination of two or more.

The content of the solvent is preferably 50% by mass or more and 98% by mass or less with respect to the total amount of the liquid crystal composition. In other words, the content of the solid content in the liquid crystal composition is preferably 2% by mass or more and 50% by mass or less. When the content of the solid content is 50% by mass or less, the viscosity of the liquid crystal composition becomes low, so that the thickness of the polarizing layer 12 becomes substantially uniform and unevenness hardly occurs in the polarizing layer 12. 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 capable of initiating a polymerization reaction such as a polymerizable liquid crystal. As the polymerization initiator, a photopolymerization initiator that generates an active radical by the action of light is preferable from the viewpoint that it does not depend on the phase state of the thermotropic liquid crystal.

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′-methyldiphenyl sulfide, 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, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl). ) Butan-1-one, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1,2-diphenyl-2,2-dimethoxyethane-1-one, 2-hydroxy-2-methyl-1 -[4-(2-Hydroxyethoxy)phenyl]propan-1-one, 1-hydroxycyclohexyl phenyl ketone and 2-hydroxy-2-methyl-1-[4-(1-methylvinyl)phenyl]propane-1- Examples thereof include ON oligomers.

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(trichloro) And methyl)-6-[2-(3,4-dimethoxyphenyl)ethenyl]-1,3,5-triazine.

A commercially available polymerization initiator 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.). SEQUOL (registered trademark) BZ, Z, and BEE (manufactured by Seiko Chemical Co., Ltd.); kayacure (registered trademark) BP100, and UVI-6992 (manufactured by Dow Chemical Co., Ltd.); Adeka Optimer SP-152; N-1717, N-1919, SP-170, ADEKA ARCRULS NCI-831, ADEKA ARCRULS NCI-930 (manufactured by ADEKA Co., Ltd.); TAZ-A, and TAZ-PP (manufactured by Japan Siber Hegner Co., Ltd.); TAZ-104 (manufactured by Sanwa Chemical Co., Ltd.); and the like. The polymerization initiator in the liquid crystal composition may be one kind, or may be a mixture of two or more kinds of polymerization initiators depending on the light source of light.

The content of the polymerization initiator in the liquid crystal composition can be appropriately adjusted according to the type and amount of the polymerizable liquid crystal compound, but is usually 0.1 part by mass with respect to 100 parts by mass of the polymerizable liquid crystal compound. Or more and 30 parts by mass or less, preferably 0.5 parts by mass or more and 10 parts by mass or less, more preferably 0.5 parts by mass or more and 8 parts by mass or less. When the content of the polymerization initiator is within the above range, the 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 (for example, 2
, 4-diethylthioxanthone, 2-isopropylthioxanthone and the like); anthracene compounds such as anthracene and an alkoxy group-containing anthracene (for example, dibutoxyanthracene and the like); 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 used is preferably 0.1 parts by mass or more and 10 parts by mass or less, more preferably 0.5 parts by mass or more and 5 parts by mass or less, with respect to 100 parts by mass of the content of the polymerizable liquid crystal compound. The amount is more preferably 0.5 parts by mass or more and 3 parts by mass or less.

(Polymerization inhibitor)
From the viewpoint of allowing the polymerization reaction to proceed stably, the liquid crystal composition may contain a polymerization inhibitor. The degree of 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 scavengers such as hydroquinone, hydroquinone containing an alkoxy group, catechol containing an alkoxy group (eg, butylcatechol), pyrogallol, 2,2,6,6-tetramethyl-1-piperidinyloxy radical, etc. 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, more preferably 100 parts by mass of the content of the polymerizable liquid crystal compound. The amount is 0.5 parts by mass or more and 5 parts by mass or less, and more preferably 0.5 parts by mass or more and 3 parts by mass or less. When the content of the polymerization inhibitor is within the above range, the polymerization can be performed without disturbing the alignment of the polymerizable liquid crystal.

(Leveling agent)
The liquid crystal composition may contain a leveling agent. The leveling agent is an additive having a function of adjusting the fluidity of the composition and making the film obtained by applying the composition more flat, for example, organic modified silicone oil type, polyacrylate type and perfluoro type. Alkyl leveling agents may be mentioned. Specifically, DC3PA, SH7PA, DC11PA, SH28PA, SH29PA, SH30PA, ST80PA, ST86PA, SH8400, SH8700, FZ2123 (all manufactured by Toray Dow Corning 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 above, Momentive Performance Materials Japan LLC) Fluorinert (registered trademark) FC-72, FC-40, FC-43, FC-3283 (all manufactured by Sumitomo 3M Limited), Megafac (registered trademark) R-08. , R-30, R-90, F-410, F-411, F-443, F-445, F-470, F-477, F-479, F-482. , F-483 (all manufactured by DIC Corporation), F-top (trade name) EF301, EF303, EF351, EF352 (all manufactured by Mitsubishi Materials Electronic Chemicals Co., Ltd.), Surflon (registered) Trademark) S-381, S-382, S-383, S-393, SC-101, SC-105, KH-40, SA-100 (all manufactured by AGC Seimi Chemical Co., Ltd.) , Trade name E1830, trade name E5844 (manufactured by Daikin Fine Chemicals Co., Ltd.), BM-1000, BM-1100, BYK-352, BYK-353 and BYK-361N (both trade names: manufactured by BM Chemie). Can be mentioned. Of these, polyacrylate-based leveling agents and perfluoroalkyl-based leveling agents are preferable.

When the liquid crystal composition contains a leveling agent, it is preferably 0.01 parts by mass or more and 5 parts by mass or less, more preferably 0.1 parts by mass or more and 5 parts by mass with respect to 100 parts by mass of the content of the polymerizable liquid crystal compound. Hereafter, it 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, it is easy to horizontally align the polymerizable liquid crystal compound and the resulting 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, the obtained polarizing film tends to have unevenness. 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 by the following formula (a), The film thickness d may be adjusted in order to obtain a desired Re(λ).

Re(λ)=d×Δn(λ) (a)
[In the formula, Re(λ) represents the retardation value at the wavelength λnm, d represents the film thickness, and Δn(λ) represents the birefringence index at the wavelength λnm].

(Coating of liquid crystal composition)
Examples of the method for applying the liquid crystal composition onto the substrate or the alignment film include an extrusion coating method, a direct gravure coating method, a reverse gravure coating method, a CAP coating method, a slit coating method, a micro gravure method, a die coating method, an inkjet method, and the like. Are listed. Further, a method of applying using a coater such as a dip coater, a bar coater, a spin coater and the like can also be mentioned. Among them, in the case of continuously applying the roll-to-roll method, microgravure method, inkjet method, slit coating method, die coating method are preferable, and when the substrate is sheet-shaped, it is possible to obtain uniform coating. High spin coating methods are preferred. When the roll-to-roll method is applied, a composition for forming a photo-alignment film for forming an alignment film is applied on a substrate to form an alignment film, and a liquid crystal composition is continuously formed on the obtained alignment film. It can also be applied selectively.

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

From the viewpoint of increasing the uniformity of the coating of the polymerizable liquid crystal compound and reducing the number of specific defects due to cissing of the coating of the polymerizable liquid crystal compound and defective alignment film, the smoothness of the surface of the substrate is improved by annealing. Can be increased. 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, for example, 1 second or more and 60 seconds or less.

By keeping the humidity of the ambient atmosphere during coating constant, it is easy to suppress crystallization of the polymerizable liquid crystal compound, and the number of specific defects due to microcrystals tends to decrease. The humidity of the ambient 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 ambient atmosphere during coating may be, for example, 10% RH or higher, and preferably 20% RH or higher. When a polymerizable liquid crystal compound having a relatively large molecular weight is used, in order to bring the number of specific defects into the range specified in the present invention, the humidity when the polymerizable liquid crystal compound is applied onto the substrate may be relatively low. 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 (in the solvent atmosphere), the solvent of the polymerizable liquid crystal compound becomes difficult to volatilize, and the crystal of the polymerizable liquid crystal compound is reduced. Formation is suppressed, and the number of specific defects due to microcrystals tends to decrease.

From the viewpoint of reducing the number of specific defects caused by foreign substances, the substrate is preferably cleaned before coating the liquid crystal composition to remove surface contamination such as PET lubricant, PET oligomer, and silicone oil. You can

In order to remove foreign matters and fine crystals in the liquid crystal composition to be coated, filtering can be performed before coating, preferably immediately before coating. In addition, the number of specific defects due to foreign matters can be reduced by applying the liquid crystal composition in a clean room.

(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, reduced pressure drying, and a combination thereof. Of these, natural drying or heat drying is preferable. The drying temperature may be, for example, in the range of 0°C to 200°C, more preferably in the range of 20°C to 150°C, still more preferably in the range of 50°C to 130°C. The drying time may be, for example, 10 seconds or more and 10 minutes or less, preferably 30 seconds or more and 5 minutes or less. The oriented polymer composition can be dried as well.

(Polymerization of polymerizable liquid crystal compound)
Photopolymerization is preferable as a method for polymerizing the polymerizable liquid crystal compound. 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. As the active energy ray to be irradiated, the type of the polymerizable liquid crystal compound contained in the dry film (particularly, the type of the photopolymerizable functional group contained in the polymerizable liquid crystal compound), and the photopolymerization initiator when it contains a photopolymerization initiator Are appropriately selected depending on the types and the amounts thereof. Specifically, one or more kinds of light selected from the group consisting of visible light, ultraviolet light, infrared light, X-rays, α rays, β rays, and γ rays can be mentioned. Among them, ultraviolet light is preferable in that it is easy to control the progress of the polymerization reaction, and that widely used in the art as a photopolymerization device can be used. It is preferable to select the type of the liquid crystalline compound.

The light source of the active energy rays, for example, low-pressure mercury lamp, medium-pressure mercury lamp, high-pressure mercury lamp, ultra-high pressure mercury lamp, xenon lamp, halogen lamp, carbon arc lamp, tungsten lamp, gallium lamp, excimer laser, wavelength range Examples thereof 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 the cationic polymerization initiator or the radical polymerization initiator. The irradiation time of light is usually 0.1 seconds or more and 10 minutes or less, preferably 0.1 seconds or more and 5 minutes or less, more preferably 0.1 seconds or more and 3 minutes or less, and further preferably 0 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 quantity is within this range, the polymerizable liquid crystal compound is sufficiently cured, good transferability tends to be obtained, and coloring of the optical layered body tends to be easily suppressed.

FIG. 1 is a schematic view showing 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 orientation layer 12, and a base material layer 13 in this order.

[Phase retardation laminate]
The retardation layered product includes one or more of the above-mentioned optical films. The retardation laminate has one or more retardation layers, and is used for converting, for example, linearly polarized light into circularly polarized light or elliptically polarized light, or conversely, to convert circularly polarized light or elliptically polarized light into linearly polarized light. May be

When the retardation laminate has the first retardation layer and the second retardation layer, the retardation laminate can be attached 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 reverse wavelength dispersive quarter-wave retardation layer and the second retardation layer may be a positive C plate, or the first retardation layer may be The ½ wavelength retardation layer may be used, and the second retardation layer may be used as the ¼ wavelength retardation layer.

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

FIG. 2 is a schematic diagram showing an embodiment of the retardation layered product. 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, and a second retardation layer 35. The alignment layer 36 and the second base material layer 37 are provided in this order.

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

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

The adhesive layer 34 can be formed from a pressure sensitive 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 an adhesive composition to the bonding surface of the base material layer or the retardation layer. As a coating method, a usual 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 adopted.

As the adhesive, it is possible to use (meth)acrylic adhesive, styrene adhesive, silicone adhesive, rubber adhesive, urethane adhesive, polyester adhesive, epoxy copolymer adhesive, etc. it can.

As the adhesive, for example, one or two or more of water-based adhesives, active energy ray-curable adhesives, pressure-sensitive adhesives and the like can be formed in combination. Examples of the water-based adhesive include a polyvinyl alcohol-based resin aqueous solution and a water-based two-component urethane-based emulsion adhesive. The active energy ray-curable adhesive is an adhesive that is cured by irradiating active energy rays such as ultraviolet rays, for example, one containing a polymerizable compound and a photopolymerizable initiator, one containing a photoreactive resin, Examples thereof include those containing a binder resin and a photoreactive crosslinking agent. 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 emits active species such as neutral radicals, anion radicals, and cation radicals upon irradiation 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. The above is 5 μm or less.

In the retardation laminate 20, for example, a step of preparing the first laminate 21 and the second retardation layer 22, and the adhesive layer 34 on the surface of the first laminate 21 on the first retardation layer 33 side. Can be manufactured by a manufacturing method including a step of forming the first laminated body 21 and the second retardation layer 22 and a step of laminating the respective retardation layer surface sides as bonding surfaces.

[Polarizer]
By combining the above retardation layered product and the polarizer, a polarizing plate, for example, an elliptical polarizing plate and a circular polarizing plate are provided.

Since the polarizing plate of the present invention has an optically anisotropic layer having 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 irregularly 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 the planar area from the outermost periphery to the inner surface. The polarizing plate may have an elongated 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 the layer 36 and the 2nd base material layer 37 in this order.

Any appropriate polarizer can be adopted as the polarizer 39. The polarizer means a linear polarizer having a property of transmitting linearly polarized light having a vibration plane orthogonal to the absorption axis when non-polarized light is incident. For example, the resin film forming the polarizer may be a single-layer resin film or a laminated film having two or more layers. The polarizer 39 may be a cured film obtained by aligning a dichroic dye with 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 polyvinyl alcohol (hereinafter sometimes abbreviated as "PVA") film, partially formalized PVA film, ethylene-vinyl acetate copolymer. A hydrophilic polymer film, such as a partially saponified system film, which has been subjected to a dyeing treatment with a dichroic substance such as iodine or a dichroic dye, and a stretching treatment, a dehydrated PVA product, or a polyvinyl chloride-free product. Examples include polyene-based oriented films such as hydrochloric acid treated products. It is preferable to use a polarizer obtained by dyeing a PVA-based film with iodine and uniaxially stretching it, because it has excellent optical properties.

The polyvinyl alcohol resin can be produced by saponifying a polyvinyl acetate resin. The polyvinyl acetate-based resin may be polyvinyl acetate, which is a homopolymer of vinyl acetate, or a copolymer of vinyl acetate and another monomer copolymerizable with 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 saponification degree of the polyvinyl alcohol resin is usually 85 mol% or more and 100 mol% or less, and preferably 98 mol% or more. The polyvinyl alcohol-based resin may be modified, and for example, polyvinyl formal or polyvinyl acetal modified with aldehydes can be used. The polymerization degree of the polyvinyl alcohol resin is usually 1,000 or more and 10,000 or less, preferably 1,500 or more and 5,000 or less.

A film formed from such a polyvinyl alcohol-based resin is used as a raw film for a polarizer. The method for forming a film of the polyvinyl alcohol-based resin is not particularly limited, and the film can be formed by a known method. The thickness of the polyvinyl alcohol-based resin original 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 for manufacturing the polarizer 39, first, a base film is prepared, a solution of a resin such as a polyvinyl alcohol resin is applied onto the base film, and drying for removing the solvent is performed to form the base film. There may be mentioned one including a step of forming a resin layer. A primer layer can be previously formed on the surface of the base film on which the resin layer is formed. A resin film such as PET can be used as the base film. Examples of the material for the primer layer include a resin obtained by crosslinking a hydrophilic resin used for a polarizer.

Then, if necessary, the amount of solvent such as water content of the resin layer is adjusted, then 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. And orientation of the functional dye on the resin layer. Subsequently, if necessary, the resin layer in which the dichroic dye is adsorbed and oriented is treated with an aqueous boric acid solution, and a washing step of washing off the aqueous boric acid solution is performed. As a result, a resin layer in which the dichroic dye is adsorbed and oriented, that is, a polarizer film is manufactured. A known method can be adopted for each step.

Uniaxial stretching of the substrate film and the resin layer may be performed before dyeing, during dyeing, or after boric acid treatment after dyeing, and each of these multiple stages is uniaxially stretched. Stretching may be performed. The base film and the resin layer may be uniaxially stretched in the MD direction (film transport direction), in which case they may be uniaxially stretched between rolls having different peripheral speeds, or may be uniaxially stretched using a heat roll. You may. 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 substrate film and the resin layer may be dry stretching in which stretching is performed in the atmosphere, 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. The upper limit of the draw ratio is not particularly limited, but is preferably 8 times or less from the viewpoint of suppressing breakage and the like.

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

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

As the dichroic dye, it is possible to use a dye having a property that the absorbance in the major axis direction of the molecule is different from the absorbance in the minor axis direction of the molecule. For example, the maximum absorption wavelength (λmax) is in the range of 300 nm to 700 nm. Dyes are preferred. Examples of such a dichroic dye include an acridine dye, an oxazine dye, a cyanine dye, a naphthalene dye, an azo dye, and an anthraquinone dye, and among them, an azo dye is preferable. Examples of azo dyes include monoazo dyes, bisazo dyes, trisazo dyes, tetrakisazo dyes and stilbeneazo dyes, and bisazo dyes and trisazo dyes are more preferable.

The composition for forming a polarizer may contain a solvent, a polymerization initiator such as a photopolymerization initiator, a photosensitizer, a polymerization inhibitor and the like. As the polymerizable liquid crystal compound, the dichroic dye, the solvent, the polymerization initiator, the photosensitizer, the polymerization inhibitor and the like contained in the composition for forming a polarizer, known compounds can be used. Those exemplified in 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-mentioned optically anisotropic layer may be used. The method exemplified in the above publication can also be adopted as a method for forming a polarizer using the composition for forming a polarizer.

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, preferably 15 μm or less. The upper limit value and the lower limit value described above can be arbitrarily combined. The smaller the thickness of the polarizer 39, the smaller the rigidity, and the more it tends to be affected by the contraction stress of the optically anisotropic layer.

A protective layer may be laminated on one side or both sides of the polarizer 39 via a known adhesive layer or adhesive layer. The protective layer that can be laminated on one side or both sides of the polarizer 39 is formed of, for example, a thermoplastic resin having excellent transparency, mechanical strength, thermal stability, moisture barrier property, isotropic property, and stretchability. 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 polyolefin resin having cyclo- and norbornene structure (also referred to as norbornene-based resin); (meth)acrylic resin; Polyarylate resin; Polystyrene resin A polyvinyl alcohol resin and a mixture thereof can be mentioned. When protective layers are laminated on both sides of the polarizer 39, the resin compositions of the two protective layers may be the same or different. In the present specification, “(meth)acrylic” means that either acrylic or methacrylic may be used. “(Meth)” such as (meth)acrylate has the same meaning.

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

The protective layer may be, for example, a stretched thermoplastic resin or a non-stretched thermoplastic resin (hereinafter, may be referred to as “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, 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. The upper limit value and the lower limit value described above can be arbitrarily combined.

The surface of the protective layer on the side opposite to the polarizer may have a surface treatment layer, for example, a hard coat layer, an antireflection layer, an antisticking layer, an antiglare layer, a diffusion layer, or the like. .. The surface treatment layer may be another layer laminated on the protective layer, or may be formed by subjecting the surface of the protective layer to surface treatment.

The hard coat layer is for the purpose of preventing scratches on the surface of the polarizing plate, and for example, adds a cured film excellent in hardness and slippage characteristics to the surface of the protective layer by an ultraviolet curable resin such as acrylic or silicone. It can be formed by a method or the like. The antireflection layer is intended to prevent reflection of external light on the surface of the polarizing plate, and can be achieved by forming an antireflection film or the like according to conventional methods. Further, the sticking prevention layer is for the purpose of preventing adhesion with an adjacent layer.

The anti-glare layer is for the purpose of preventing external light from being reflected on the surface of the polarizing plate and hindering the visual recognition of the transmitted light of the polarizing plate. For example, a rough surface by a sandblast method or an embossing method is used. A fine uneven structure can be formed on the surface of the protective layer by a method such as a chemical method or a method of mixing transparent fine particles. Examples of the transparent fine particles used for imparting a fine uneven structure to the surface of the protective layer include silica, alumina, titania, zirconia, tin oxide, indium oxide, cadmium oxide, antimony oxide having an average particle size of 0.5 μm or more and 50 μm or less. Examples thereof include fine particles such as inorganic fine particles capable of having conductivity and organic fine particles such as crosslinked or uncrosslinked polymer. The content of the transparent fine particles is generally 2 parts by mass or more and 50 parts by mass or less, and preferably 5 parts by mass or more and 25 parts by mass or less, with respect to 100 parts by mass of the resin forming the layer forming the fine concavo-convex structure. The anti-glare layer may also serve as a diffusion layer (viewing angle enlarging function, etc.) for diffusing the light transmitted through the polarizing plate and enlarging the viewing angle.

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, scratches on the surface of the polarizing plate tend to be effectively prevented, curing shrinkage is suppressed, and reverse curl of the polarizing plate tends to be suppressed easily.

The adhesive layer 38 can be made 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, a pressure-sensitive adhesive having a base polymer such as an acrylic type, a urethane type, a silicone type, or a polyvinyl ether type is used. be able to. Further, it may be an active energy ray-curable adhesive, a thermosetting adhesive, or the like. Among these, a pressure-sensitive adhesive using an acrylic resin as a base polymer, which is excellent in transparency, adhesive strength, removability, weather resistance, heat resistance, etc., is preferable. The adhesive layer is preferably composed of a reaction product of an adhesive composition containing a (meth)acrylic resin, a crosslinking agent, and a silane compound.

The pressure-sensitive adhesive composition is blended with a UV-curable compound such as a polyfunctional acrylate to give an active energy ray-curable pressure-sensitive adhesive, and after forming an adhesive layer of the active energy ray-curable pressure-sensitive adhesive, it is irradiated with ultraviolet rays and cured. It is also useful to use a harder adhesive layer. The active energy ray-curable pressure-sensitive adhesive has the property of being cured by being irradiated with energy rays such as ultraviolet rays and electron rays. Since the activated energy ray-curable pressure-sensitive adhesive has adhesiveness even before irradiation with energy rays, it adheres to an adherend such as an optical film or a liquid crystal layer and is cured by irradiation with energy rays to improve adhesion. It is an adhesive having the property of being adjustable.

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 added, and if necessary, a photopolymerization initiator, a photosensitizer and the like can be added.

The adhesive layer 38 may have a thickness of, 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 flexible image display device laminate and an organic EL display panel. The flexible image display device laminate is disposed on the viewer side of the organic EL display panel and is configured to be bendable. There is. Being foldable means capable of being bent without cracking and breaking. As a laminate for a flexible image display device,
It may be a polarizing plate including at least one of the front plate and the touch sensor. When the polarizing plate has both the front plate and the touch sensor, the order of stacking them is arbitrary. It is preferable that they are laminated 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 less visible and the visibility of the display 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 the front plate, the polarizing plate, and the touch sensor can be provided. Each layer (front plate, polarizing plate, touch sensor) forming the laminate for a flexible image display device and the film member (linear polarizing plate, quarter-wave retardation plate, etc.) forming each layer may be formed by an adhesive. it can. The polarizing plate is a polarizing plate containing the optical film or the retardation laminate of the present invention, 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 that can transmit 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 arranged, for example, on the viewing side of a flexible image display device described later, and has a role of protecting other components from external impacts or environmental changes such as temperature and humidity. Conventionally, glass has been used as such a protective layer, but the window in a flexible image display device to be described later is not rigid and rigid like glass, but 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 unit of a monomer containing cycloolefin, and (modified) cellulose such as diacetyl cellulose, triacetyl cellulose and propionyl cellulose. , Acrylics such as methyl methacrylate (co)polymers, polystyrenes such as styrene (co)polymers, acrylonitrile/butadiene/styrene copolymers, acrylonitrile/styrene copolymers, ethylene-vinyl acetate copolymers Polyvinyl chloride, polyvinylidene chloride, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polycarbonate, polyesters such as polyarylate, polyamides such as nylon, polyimides, polyamideimides, polyetherimides, It may be a film formed of a polymer such as polyether sulfones, polysulfones, polyvinyl alcohols, polyvinyl acetals, polyurethanes, and epoxy resins, and an unstretched uniaxially or biaxially stretched film should be used. You can These polymers can be used alone or in admixture of two or more. Of the above transparent substrates, a polyamide film, a polyamideimide film or a polyimide film, which is excellent in transparency and heat resistance, a polyester film, an olefin film, an acrylic film, and a cellulose film are preferable. It is also preferable to disperse inorganic particles such as silica, organic fine particles, rubber particles and the like in the polymer film. Furthermore, colorants such as pigments and dyes, optical brighteners, dispersants, plasticizers, heat stabilizers, light stabilizers, infrared absorbers, ultraviolet absorbers, antistatic agents, antioxidants, lubricants, solvents, etc. You may contain the compounding agent of. The thickness of the transparent substrate is 5
It is at least 200 μm and preferably at least 20 μm and at most 100 μm.

(Hard coat)
A hard coat layer may be provided on at least one surface of the transparent substrate in the window. 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. If the thickness of the hard coat layer is less than 2 μm, it is difficult to secure sufficient scratch resistance, and if it exceeds 100 μm, the flex resistance may be deteriorated and curling may occur due to curing shrinkage.

The hard coat layer can be formed by curing a hard coat composition containing a reactive material that forms a crosslinked structure by irradiating with active energy rays or heat energy, but is preferably cured by active energy rays. An active energy ray is defined as an energy ray capable of decomposing a compound generating an active species to generate an active species. Examples of active energy rays include visible light, ultraviolet rays, infrared rays, X-rays, α rays, β rays, γ rays and electron rays. 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 radically polymerizable compound is a compound having a radically polymerizable group. The radical polymerizable group contained in the radical 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 thereof 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 contained in one molecule of the radically polymerizable compound is preferably 2 or more from the viewpoint of improving the hardness of the hard coat layer. From the viewpoint of high reactivity, the radically polymerizable compound is preferably a compound having a (meth)acryloyl group, and is referred to as a polyfunctional acrylate monomer having 2 to 6 (meth)acryloyl groups in one molecule. Compounds and epoxy (meth)acrylates, urethane (meth)acrylates, polyester (meth)acrylates, which have several (meth)acryloyl groups in the molecule, are preferably used oligomers with a molecular weight of several hundred to several thousand. it can. It is preferable to include 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 2 or more, and more preferably 3 or more from the viewpoint of improving the hardness of the hard coat layer. In addition, as the cationically polymerizable compound, among others, a compound having at least one of an epoxy group and an oxetanyl group as a cationically polymerizable group is preferable. A cyclic ether group such as an epoxy group or an oxetanyl group is preferable from the viewpoint that the shrinkage accompanying the polymerization reaction is small. In addition, compounds having an epoxy group among cyclic ether groups are easily available as compounds having various structures, do not adversely affect the durability of the obtained hard coat layer, and easily control the compatibility with the radically polymerizable compound. There is an advantage that. Further, among the cyclic ether groups, the oxetanyl group is more likely to have a higher degree of polymerization than the epoxy group and has low toxicity, and accelerates the network formation rate obtained from the cationically polymerizable compound of the obtained hard coat layer, and radicals. Even in a region mixed with a polymerizable compound, there is an advantage that an unreacted monomer is not left in the film and an independent network is formed.

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

The hard coat composition may further include a polymerization initiator. As the polymerization initiator, there are radical polymerization initiators, cationic polymerization initiators, radical and cationic polymerization initiators, etc., which can be appropriately selected and used. These polymerization initiators are decomposed by at least one of irradiation with active energy rays and heating to generate radicals or cations to promote radical polymerization and cation polymerization.

The radical polymerization initiator may be any substance that can release a substance that initiates radical polymerization by at least one of irradiation with active energy rays and heating. Examples of thermal radical polymerization initiators include hydrogen peroxide, organic peroxides such as perbenzoic acid, and azo compounds such as azobisbutyronitrile.

As the active energy ray radical polymerization initiator, a Type 1 type radical polymerization initiator that generates a radical by decomposition of a molecule and a Type 2 type radical polymerization initiator that coexists with a tertiary amine to generate a radical by a hydrogen abstraction type reaction Yes, they can be used alone or in combination.

Any cationic polymerization initiator may be used as long as it can release 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 or the like can be used. These can initiate cationic polymerization either by irradiation with active energy rays or by heating, or both, depending on the difference in structure.

The polymerization initiator may be included in an amount of 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, curing cannot be sufficiently progressed, and it is difficult to realize the mechanical properties and adhesion of the finally obtained coating film. If it exceeds %, defective adhesion due to curing shrinkage, cracking phenomenon and curling phenomenon may occur.

The hard coat composition may further include one or more selected from the group consisting of a solvent and an additive. The solvent can dissolve or disperse the polymerizable compound and the polymerization initiator, and any solvent known as a solvent for the hard coat composition in the present technical field can be used without limitation. The additives may further include inorganic particles, leveling agents, stabilizers, surfactants, antistatic agents, lubricants, antifouling agents and the like.

(Circular polarization 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 ¼ wavelength retardation layer (hereinafter, also referred to as a λ/4 retardation layer) on a linear polarizing plate. .. For example, by converting the external light into right circularly polarized light, blocking the external light reflected by the organic EL panel to become left circularly polarized light, and transmitting only the luminescent component of the organic EL, the effect of reflected light is suppressed and the image is displayed. It is used to make it easier to see. In order to achieve the circular polarization function, the absorption axis of the linear polarizer or the linear polarizing plate and the slow axis of the λ/4 retardation layer need to be 45° theoretically, but practically 45±10. °. The linear polarizer or the linear polarizing plate and the λ/4 retardation layer do not necessarily have to 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 practice, so the circularly polarizing plate in the present invention includes an elliptically polarizing plate. It is also preferable to further laminate a λ/4 retardation film on the viewing side of the linear polarizer or the linear polarizing plate to make the emitted light circularly polarized light to improve the visibility in the state where polarized sunglasses are worn.

The linearly polarizing plate is a functional layer having a function of transmitting light oscillating in the transmission axis direction but blocking polarized light of an oscillating component perpendicular to the light. The linear polarizing plate may have a configuration including 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 decrease.

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

Still another example of the linear polarizer may be a liquid crystal coating type polarizer formed by coating a liquid crystal polarizing composition. The liquid crystal polarizing composition may include a liquid crystal compound and a dichroic dye compound. The liquid crystal compound may have a property of exhibiting a liquid crystal state, and in particular, it is preferable that it has a higher order alignment state such as a smectic phase because high polarization performance can be exhibited. It is also preferable to have a polymerizable functional group. The dichroic dye compound is a dye that is aligned with the liquid crystal compound and exhibits dichroism, and the dichroic dye itself may have liquid crystallinity or has a polymerizable functional group. Can also Any of the compounds in the liquid crystal polarizing composition has a polymerizable functional group. The liquid crystal polarizing composition may further contain an initiator, a solvent, a dispersant, a leveling agent, a stabilizer, a surfactant, a cross-linking agent, a silane coupling agent and the like. The liquid crystal polarizing layer can be manufactured by applying a liquid crystal polarizing composition on the alignment film to form a liquid crystal polarizing layer. The liquid crystal polarizing layer can be formed thinner than the film-type 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 the composition for forming an alignment film on a substrate and imparting the alignment property by rubbing, irradiation of polarized light, or the like. The alignment film forming composition may contain a solvent, a cross-linking agent, an initiator, a dispersant, a leveling agent, a silane coupling agent and the like in addition to the aligning agent. As the aligning agent, for example, polyvinyl alcohols, polyacrylates, polyamic acids, and polyimides can be used. When applying photo-alignment, it is preferable to use an aligning agent containing a cinnamate group. The weight average molecular weight of the polymer used as the aligning agent may be about 10,000 to 1,000,000. The orientation film is preferably 5 nm or more and 10000 nm or less, and particularly preferably 10 nm or more and 500 nm or less because the orientation regulating force is sufficiently exhibited. The liquid crystal polarizing layer may be peeled from the substrate and transferred to be laminated, or the substrate may 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 may be a transparent polymer film, and the materials and additives used for the transparent substrate can be used. Cellulose type films, olefin type films, acrylic films and polyester type films are preferable. It may be a coating type protective film obtained by applying and curing a cationically curable composition such as an epoxy resin or a radical curable composition such as an acrylate. If necessary, plasticizers, ultraviolet absorbers, infrared absorbers, colorants such as pigments and dyes, optical 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 decrease. It can also serve as the transparent base material of the window.

The λ/4 retardation layer may be the optical film of the present invention, or may be a film that imparts a λ/4 retardation in a direction orthogonal to the traveling direction of incident light (in-plane direction of the film). .. The film that gives a retardation of λ/4 may be a stretchable retardation plate produced by stretching a polymer film such as a cellulose film, an olefin film, or a polycarbonate film. If necessary, retarder, plasticizer, ultraviolet absorber, infrared absorber, colorant such as pigment or dye, fluorescent whitening agent, dispersant, heat stabilizer, light stabilizer, antistatic agent, antioxidant. , A lubricant, a solvent, etc. may be contained. The thickness of the stretchable 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 decrease. The λ/4 retardation layer is preferably the optical film of the present invention from the viewpoint of workability and flexibility.

Further, as another example of the λ/4 retardation layer, a liquid crystal coating type retardation plate formed by coating a liquid crystal composition may be used. The liquid crystal composition contains a liquid crystal compound having a property of exhibiting a liquid crystal state such as nematic, cholesteric, and smectic. Any of the compounds including the liquid crystal compound in the liquid crystal composition has a polymerizable functional group. The liquid crystal coated retardation plate may further contain 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 coated retardation plate can be produced by coating and curing the liquid crystal composition on the alignment film to form the liquid crystal retardation layer, as in the case of the liquid crystal polarizing layer. The liquid crystal coating type retardation plate can be formed thinner than the stretched retardation plate. 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 coating type retardation plate may be peeled from the substrate and transferred to be laminated, or the substrate may 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, many materials exhibit large birefringence at shorter wavelengths and smaller birefringence at longer wavelengths. 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, which is λ/4 near 560 nm with high visibility, preferably 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 made of a material having a birefringence wavelength dispersion characteristic opposite to the usual one because the visibility can be improved. As such a material, it is also preferable to use the materials described in JP-A-2007-232873 in the case of a stretched retardation plate and the JP-A-2010-30979 in the case of a liquid crystal coated retardation plate. ..

As another method, there is known a technique of obtaining a broadband λ/4 retardation layer by combining with a ½ wavelength retardation layer (hereinafter, also referred to as λ/2 retardation layer) (Japanese Patent Laid-Open No. 10- 90521 publication). The λ/2 retardation layer may also be the optical film of the present invention, or may be one produced by the same material and method as the λ/4 retardation layer. The combination of the stretched retardation plate and the liquid crystal coated retardation plate is arbitrary, but it is preferable to use the liquid crystal coated retardation plate for both because the film thickness can be reduced. The λ/2 retardation layer is preferably the optical film of the present invention from the viewpoint of workability and flexibility.

There is also known a method of laminating a positive C plate on the circularly polarizing plate in order to enhance visibility in an oblique direction (Japanese Patent Laid-Open No. 2014-224837). The positive C plate may also be the optical film of the present invention, a liquid crystal coating type 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 layered product in combination with a λ/4 retardation layer.

(Touch sensor)
The touch sensor is used as an input means. As the touch sensor, various types such as a resistance film type, a surface acoustic wave type, an infrared type, an electromagnetic induction type, and a capacitance type have been proposed, and any type may be used. Of these, the capacitance method is preferable. The capacitive touch sensor is divided into an active region and a non-active region located outside the active region. The active region is a region corresponding to a region where the screen is displayed on the display panel (display unit), and is a region where the user's touch is sensed, and the inactive region is a region where the screen is not displayed on the image display device ( It is an area corresponding to the (non-display portion). The touch sensor includes a substrate having a flexible characteristic; a sensing pattern formed in an active region of the substrate; and a sensing pattern formed in an inactive region of the substrate for connecting to an external driving circuit through the sensing pattern and the pad portion. A sensing line can be included. As the substrate having flexible characteristics, the same material as the transparent substrate for the window can be used. The substrate for 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 2,000 MPa% or more and 30,000 MPa% or less.

The sensing pattern may include a first pattern formed in the first direction and a second pattern formed in the 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 the respective patterns must be electrically connected in order to detect a touched point. The first pattern has a form in which the unit patterns are connected to each other through a joint, but the second pattern has a structure in which the unit patterns are separated from each other in an island shape. A separate bridge electrode is required to make the connection. A known transparent electrode material can be applied to the sensing pattern. 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 and the like, and these may be used alone or in combination of two or more kinds. 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, ternium, and chromium. These may be used alone or in combination of two or more.

The bridge electrode may be formed on the insulating layer via the insulating layer on the sensing pattern, and the bridge electrode is formed on the substrate, and the insulating layer and the sensing pattern may be formed on the bridge electrode. 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 pattern and the second pattern 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 the structure of the layer 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. A touch sensor is a difference in transmittance between a patterned area where a pattern is formed and a non-patterned area where no pattern is formed, specifically, a difference in light transmittance induced by a difference in refractive index in these areas. 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 adjustment layer may be formed by coating a photocurable composition containing a photocurable organic binder and a solvent on a substrate. The photocurable composition may further include inorganic particles. The refractive index of the optical adjustment layer can be increased by the inorganic particles.

The photo-curable organic binder may include, for example, a copolymer of each monomer such as an acrylate-based monomer, a styrene-based monomer, and a carboxylic acid-based 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 various additives such as a photopolymerization initiator, a polymerizable monomer, and a curing aid.

(Adhesive layer)
Each layer (window, circularly polarizing plate, touch sensor) and film members (linear polarizing plate, λ/4 retardation plate, etc.) forming each layer can be formed by an adhesive. As the adhesive, a water-based adhesive, an organic solvent-based adhesive, a solvent-free adhesive, a solid adhesive, a solvent volatilizing adhesive, a moisture-curable adhesive, a heat-curable adhesive, an anaerobic-curable adhesive, an active energy ray-curable adhesive Adhesives, hardener-mixed adhesives, hot-melt adhesives, pressure-sensitive adhesives (adhesives), rewet adhesives, and other commonly used adhesives can be used. Of these, water-based solvent volatilizing adhesives, active energy ray-curing 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, and when there are a plurality of adhesive layers, The thickness types may be the same or different.

As the water-based water-based solvent volatilization type adhesive, a polyvinyl alcohol-based polymer, a water-soluble polymer such as starch, and a water-dispersed polymer such as an ethylene-vinyl acetate emulsion and a styrene-butadiene-based emulsion can be used as a main polymer. In addition to water and the base 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 added. In the case of adhering with a water-based water-based solvent volatilizing adhesive, the water-based water-based solvent volatilizing adhesive is injected between the adhered layers to bond the adhered layers and then dried to impart adhesiveness. When the water-based water-based solvent volatilizing adhesive is used, the thickness of the adhesive layer may be 0.01 μm or more and 10 μm or less, preferably 0.1 μm or more and 1 μm or less. When a plurality of water-based water-based solvent volatile adhesives are used, 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 is irradiated with an active energy ray to form an adhesive layer. The active energy ray-curable composition can contain at least one polymer of the same radically polymerizable compound and cationically polymerizable compound as in the hard coat composition. The radically polymerizable compound is the same as the hard coat composition, and the same kind as the hard coat composition can be used. The radically polymerizable compound used in the adhesive layer is preferably a compound having an acryloyl group. It is also preferable to include a monofunctional compound in order to reduce the viscosity of the adhesive composition.

The cationically polymerizable compound is the same as the hard coat composition, and the same kind as the hard coat composition can be used. An epoxy compound is particularly preferred as the cationically polymerizable compound used in the active energy ray-curable composition. 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. As the polymerization initiator, there are radical polymerization initiators, cationic polymerization initiators, radical and cationic polymerization initiators, etc., which can be appropriately selected and used. These polymerization initiators are decomposed by at least one of irradiation with active energy rays and heating to generate radicals or cations to promote radical polymerization and cation polymerization. In the description of the hard coat composition, an initiator capable of initiating radical polymerization and/or 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 defoaming agent solvent, an additive and a solvent. Can be included. In the case of bonding with an active energy ray-curable adhesive, the active energy ray-curable composition is applied to either or both of the adherend layers and then laminated, and the active energy ray is passed through either adherent layer or both adherent layers. It can be adhered by irradiating and curing. The thickness of the adhesive layer when using the active energy ray-curable adhesive 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 active energy ray-curable adhesives are used, the thickness of each layer may be the same or different.

The pressure-sensitive adhesive may be classified into an acrylic pressure-sensitive adhesive, a urethane pressure-sensitive adhesive, a rubber pressure-sensitive adhesive, a silicone pressure-sensitive adhesive, etc. depending on the base polymer, and any of these may be used. In addition to the base polymer, the adhesive may contain a crosslinking agent, a silane compound, an ionic compound, a crosslinking catalyst, an antioxidant, a tackifier, a plasticizer, a dye, a pigment, an inorganic filler and the like. Each component constituting the pressure-sensitive adhesive is dissolved/dispersed in a solvent to obtain a pressure-sensitive adhesive composition, and the pressure-sensitive adhesive composition is applied onto a substrate and then dried to form a pressure-sensitive adhesive layer adhesive layer. The adhesive layer may be directly formed, or may be separately formed on the substrate and transferred. It is also preferable to use a release film to cover the adhesive surface before adhesion. The thickness of the adhesive layer when using the active energy ray-curable adhesive 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 adhesive layers 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 the bezel or the housing of the flexible image display device. The light-shielding pattern hides the wiring arranged at the peripheral portion of the flexible image display device to make it difficult to be visually recognized, thereby improving the visibility of the image. The light blocking 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 metallic colors. The light-shielding pattern can be formed of a pigment for realizing a color and a polymer such as acrylic resin, ester resin, epoxy resin, polyurethane or silicone. These can be used alone or as a mixture of two or more kinds. 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, and preferably 2 μm or more and 50 μm or less. It is also preferable to give a shape such as an inclination in the thickness direction of the light pattern.

FIG. 4 is a schematic cross-sectional view according to one aspect of the flexible image display device. The 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. Unless otherwise specified, "%" and "parts" in the examples are mass% and parts by mass. 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 a size of 50 mm×50 mm, and an optical microscope (ECLIPSE
The actual size and number of alignment defects on the screen were confirmed using ME600 (manufactured by Nikon Corporation). When observing, insert a linear polarizing plate under the stage of the optical microscope. Then, the slow axis direction of the obtained optical film and the absorption axis direction of the linearly polarizing plate inserted in the lower part of the stage are aligned. Furthermore, the polarizer of the optical microscope was rotated to make it in a crossed Nicol state, and the region which became a bright spot was made an alignment defect. The actual size of the alignment defect was determined by measuring the length of the portion where the dimension of the defect region which is visually recognized when the region is depolarized is observed. As a result of observation, all the defects were caused by the crystals of the polymerizable liquid crystal compound. The results are shown in Table 2. The actual defect size shown in Table 2 is an average value of the measured actual sizes. In each of the cut out optical films, the number of defects having an actual size of more than 50 μm was 6/mm ² or less.

<ECLIPSE observation settings>
Illuminance: Fully open Lower diaphragm: 0.5
Exposure time: 200ms
GAIN: 2.00
AWB: Not set

[Defect rate of optically anisotropic layer]
After measuring the number of the above defects, a one-field image (including the defect portion) in a crossed Nicol state of an optical microscope is displayed on a personal computer so that there is 256 gradations between the brightest part and the darkest part. The captured image was binarized using the image processing software attached to the personal computer under the condition of the threshold value 127, the area of the alignment defect was determined, and the defect rate was calculated. The results are shown in Table 2.

[Measurement of piercing strength]
For the puncture test, a handy compression tester “KES-G5 Needle Penetration Measurement Specification” manufactured by Kato Tech Co., Ltd. equipped with a spherical needle (tip diameter 1 mmφ, 0.5 R) was used, and the temperature was 23±3° C. The measurement was performed under the measuring conditions of a puncture speed of 0.0033 cm/sec.
The puncture strength measured by the puncture test was the average value of the puncture tests performed on three test pieces. The results are shown in Table 2.

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

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 formula 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 JP2011-207765A.

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

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

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

The liquid crystal composition solution (1) is prepared by charging the liquid crystal mixture (1), the polymerization initiator, the leveling agent, the polymerization inhibitor and the solvent according to the composition described in Table 1 with reference to Patent Document (JP-A-2017-179367). Prepared. The amounts of the polymerization initiator, the leveling agent and the polymerization inhibitor shown in Table 1 are the charged amounts with respect to 100 parts by mass of the liquid crystal mixture (1). Moreover, the compounding amount of the solvent was set such that the mass% of the liquid crystal mixture (1) was 10 mass% with respect to the total amount of the liquid crystal composition solution [the liquid crystal mixture was added to 1000 parts by mass of the liquid crystal composition solution (1). (1) The solvent was added so that 100 parts by mass was included].

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

溶剤（９５部）：シクロペンタノン [Composition for forming photo-alignment film]
The components below were mixed, and the obtained mixture was stirred at 80° C. for 1 hr to obtain a composition (1) for forming a photo-alignment film. The photo-alignment material represented by the following formula was synthesized by the method described in JP2013-33248A.
Photo-alignment material (5 parts):

Solvent (95 parts): Cyclopentanone

[Example 1]
The optical film was manufactured as follows. Cycloolefin polymer film (COP) (ZF-14, manufactured by Nippon Zeon Co., Ltd., thickness 23 μm, heat capacity per substrate 1 cm ² is 0.004 J/cm ² ·° C.), corona treatment device (AGF-B10, Kasuga Denki). (Manufactured by Co., Ltd.) was processed once under the conditions of an output of 0.3 kW and a processing speed of 3 m/min. The composition for photo-alignment film formation (1) was applied to the corona-treated surface by a bar coater, dried at 80° C. for 1 minute, and then polarized UV irradiation device (SPOT CURE SP-7; manufactured by USHIO INC.). Was used to perform polarized UV exposure with an integrated light amount of 100 mJ/cm ² . When the thickness of the obtained alignment film was measured by a laser microscope (LEXT, manufactured by Olympus Corporation), it was 100 nm.

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

[Example 2]
An optical film was prepared in the same manner as in Example 1, except that the substrate with an 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 coated.

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

[Example 5]
Example 1 was repeated except that the composition ratio of the polymerizable liquid crystal compound was 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 created.

[Example 6]
As a base material, a non-coated surface of COP (a surface on which the liquid crystal composition solution was not coated) was bonded to a soda glass plate having a thickness of 0.3 mm with an adhesive to prepare a substrate. The heat capacity of this base material was 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 base material was used.

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

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

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

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

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

<Production of second retardation layer>
A PET substrate having a thickness of 38 μm was used as a transparent substrate, one side of which was coated with the composition for vertical alignment layer to a film thickness of 3 μm, and ultraviolet rays were irradiated to form an alignment layer. 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 of LUCIRIN TPO added at a ratio of 4% was used as a polymerization initiator.

Subsequently, a liquid crystal composition containing a photopolymerizable nematic liquid crystal (RMM28B, manufactured by Merck & Co., Inc.) was applied onto the formed 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 that the solid content was 1 to 1.5 g was applied onto the alignment layer so that the application 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. Then, it was polymerized by irradiation with ultraviolet rays (UV) to obtain a positive C layer composed of a layer in which a photopolymerizable nematic liquid crystal compound was cured, an alignment layer, and a transparent substrate. The total thickness of the layer in which the photopolymerizable nematic liquid crystal compound was cured and the alignment layer was 4 μm.

<Production of retardation layered product>
The first retardation layer and the second retardation layer were bonded together by an ultraviolet curable adhesive so that each retardation layer surface (the surface on the side opposite to the transparent substrate) became the bonding surface. .. Next, ultraviolet rays were irradiated to cure the ultraviolet curable adhesive. In this way, a retardation laminate (1) including two retardation layers of the first retardation layer and the 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 was immersed in pure water at 30° C., and then the iodine:potassium iodine:water mass ratio was 0.02:2. : Iodine dyeing was performed by immersing in an aqueous solution of 100 at 30° C. (hereinafter, also referred to as iodine dyeing step). The polyvinyl alcohol film that had been subjected to the iodine dyeing step was immersed in an aqueous solution having a mass ratio of potassium iodide:boric acid:water of 12:5:100 at 56.5°C to perform boric acid treatment (hereinafter, boric acid treatment Also called process). The polyvinyl alcohol film that had been subjected to the boric acid treatment step was washed with pure water at 8° C. and then dried at 65° C. to obtain a polarizer (thickness after stretching was 12 μm) in which iodine was 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 this stretching was 5.3 times.

A saponified triacetyl cellulose film (KC4UYTAC 40 μm manufactured by Konica Minolta Co., Ltd.) was attached to both surfaces of the obtained polarizer by a nip roll via an aqueous adhesive. While maintaining the tension of the obtained bonded product at 430 N/m, it was dried at 60° C. for 2 minutes to obtain a polarizer (1) having a triacetyl cellulose film as a protective film on both surfaces. The water-based adhesive contained 100 parts of water, 3 parts of carboxy group-modified polyvinyl alcohol (Kuraray Co., Ltd., Kuraray Poval KL318), and water-soluble polyamide epoxy resin (Taoka Chemical Co., Ltd., Sumirez Resin 650, solid content concentration: 30). % Aqueous solution).

Optical properties of the obtained polarizer (1) were measured using a spectrophotometer (V7100, manufactured by JASCO Corporation). The resulting visibility-corrected single transmittance was 42.1%, the visibility-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 as the first pressure-sensitive adhesive layer to one surface of the polarizer (1), the separate film was peeled off, and the transparent base material on the first retardation layer side of the retardation laminate (1) was peeled off. Laminated on the surface. A 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, a polarized light including a protective film, a polarizer, a protective film, a first pressure-sensitive adhesive layer, a first retardation layer, an adhesive layer, a second retardation layer, and a second pressure-sensitive adhesive layer in this order. A plate was made.

[Evaluation method of workability of polarizing plate]
When the obtained polarizing plate was cut into 100 mm x 100 mm with a super cutter, the cut end face was observed with an optical microscope, and three or more cracks were found in the retardation laminate, 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 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 polyimide film having a thickness of 75 μm (manufactured by Ube Industries, Upilex S model number 75S). Thus, 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, the polyimide film A polarizing plate with a polyimide film, which was included in order, was produced.

[Method of evaluating flex resistance of polarizing plate with polyimide film]
When the obtained polarizing plate with a polyimide film was cut into 100 mm×10 mm with a super cutter and bent at 0.5 R so that the polyimide film was convex, five or more cracks were found in the retardation layer. Those that were seen were marked with x, those that were found 1 to 4 were marked with ◯, and those that were not found were marked with ⊚. The length of cracks generated in Example 1 was 250 μm, and the length of cracks generated in Comparative Example 3 was 220 μm to 250 μm, and there was no difference in the length of cracks between Example 1 and Comparative Example 3.

10 optical film, 11 optically anisotropic layer, 12 alignment layer, 13 base material layer, 20 retardation laminate, 31 first base material layer, 32 first alignment layer, 33 first retardation layer, 34 Adhesive layer, 35 Second retardation layer, 36 Second alignment layer, 37 Second base material layer, 38 Adhesive layer, 39 Polarizer, 40 Polarizing plate.

Claims (12)

An optical film having an optically anisotropic layer comprising a polymer polymerized in a state in which a polymerizable liquid crystal compound having one or more polymerizable functional groups is aligned,
An optical film, wherein the number of alignment defects in which the actual size of the optically anisotropic layer per 1 mm ² is 0.3 μm or more and 50 μm or less satisfies the following formula (1).
0≦number of orientation defects [pieces]≦14 (1) An optical film having an optically anisotropic layer comprising a polymer polymerized in a state in which a polymerizable liquid crystal compound having one or more polymerizable functional groups is aligned,
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 area of defects is 0.3 μm in the actual size observed in one field of the optical microscope.
It is the total of the areas of the alignment defects of 50 μm or less, and the microscope observation field is the area of the optically anisotropic layer when the optically anisotropic layer is present over the entire field of the optical microscope.
0 ≤ defect rate [ppm] ≤ 1000 (3) An optical film having an optically anisotropic layer comprising a polymer polymerized in a state in which a polymerizable liquid crystal compound having one or more polymerizable functional groups is aligned,
The number of alignment defects in which the actual size of the optically anisotropic layer per 1 mm ² is 0.3 μm or more and 50 μm or less satisfies the following formula (1), and the defect rate defined by the following formula (2) is the following formula ( An optical film satisfying 3).
0≦number of orientation defects [pieces]≦14 (1)

[In the formula, the total area of defects is 0.3 μm in the actual size observed in one field of the optical microscope.
It is the total of the areas of the alignment defects of 50 μm or less, and the microscope observation field is the area of the optically anisotropic layer when the optically anisotropic layer is present over the entire field of the optical microscope.
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 fine crystals of a polymerizable liquid crystal compound. The optical film according to claim 1, wherein the optically anisotropic layer has a thickness of 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 or 9, which is a deformed polarizing plate. The polarizing plate according to claim 8, 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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