WO2022050003A1

WO2022050003A1 - Optical laminate, and ellipsoidally polarizing plate including same

Info

Publication number: WO2022050003A1
Application number: PCT/JP2021/029483
Authority: WO
Inventors: 伸行幡中; 耕太村野
Original assignee: 住友化学株式会社
Priority date: 2020-09-07
Filing date: 2021-08-10
Publication date: 2022-03-10
Also published as: TW202214429A; CN116057430A; JP2022044293A; KR20230062548A

Abstract

The purpose of the present invention is to provide an optical laminate in which strain does not readily occur when the laminate is bent, and which has high flexibility and exceptional oblique reflectance, and particularly to provide an optical laminate that is suitable for a flexible display.　An optical laminate including a phase difference film, a polarizer, and a transparent protective film in the stated order, wherein: the phase difference film includes a base film having a moisture permeability of 100 g/m²/24 hours or greater, and a liquid crystal cured film that is formed on the base film, has a thickness of 0.5-3 µm (inclusive), and satisfies, as a single layer, formulas (1) and (2) (formula (1): Re(450)/Re(550)≤1.00, and formula (2): 1.00≤Re(650)/Re(550), where Re (λ) represents the in-plane phase difference value at the wavelength λ); the polarizer is configured from a polyvinyl alcohol resin film that contains a dichroic pigment; the transparent protective film has a total light transmittance of 90% or greater and a 380 nm transmittance of 30% or less; and the phase difference film, the polarizer, and the transparent protective film are adjacent with adhesive layers interposed therebetween.

Description

Optical laminate and elliptical polarizing plate containing it

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

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

Japanese Unexamined Patent Publication No. 2011-207765

In recent years, there has been a demand for flexibility of a display, and an elliptical polarizing plate having a thinness and high flexibility is required. A retardation film obtained by curing a polymerizable liquid crystal compound as described in Reference 1 is suitable for a flexible display from the viewpoint of realizing thinning, and is formed from such a cured liquid crystal film. An elliptical polarizing plate (membrane) can be produced by transferring the phase difference plate (membrane) to the polarizing plate via a pressure-sensitive pressure-sensitive adhesive.
However, when the present inventors transfer the retardation plate formed from the liquid crystal cured film using a pressure-sensitive pressure-sensitive adhesive, distortion occurs at the bending point when the elliptical polarizing plate formed by the retardation plate is bent. It is easy to find that this can cause streak-like defects and an increase in light reflectance (diagonal reflectance) from an oblique direction.

An object of the present invention is to provide an optical laminate that is less likely to be distorted when bent and is excellent in high flexibility and oblique reflectance, particularly an optical laminate suitable for a flexible display.

As a result of diligent studies to solve the above problems, the present inventors have completed the present invention. That is, the present invention includes the following aspects.
[1] An optical laminate containing a retardation film, a splitter, and a transparent protective film in this order.
The retardation film has a base film having a moisture permeability of 100 g / m ^2/24 hours or more, and a thickness of 0.5 μm or more and 3 μm or less formed on the base film, and the following formula ( 1) and (2):
Re (450) / Re (550) ≤ 1.00 (1)
1.00 ≤ Re (650) / Re (550) (2)
[In the equation, Re (λ) indicates the in-plane phase difference value at the wavelength λ]
Contains a liquid crystal cured film, which fills with a single layer,
The polarizing element is composed of a polyvinyl alcohol-based resin film containing a dichroic dye, and the transparent protective film has a total light transmittance of 90% or more and a 380 nm transmittance of 30% or less.
An optical laminate in which the retardation film, the polarizing element, and the transparent protective film are adjacent to each other via an adhesive layer.
[2] The base film has a total light transmittance of 90% or more, and the absolute value of the phase difference value Rth (550) in the thickness direction with respect to light of 550 nm is 5 nm or less. The optical laminate according to the description.
[3] The optical laminate according to the above [1] or [2], wherein the retardation film has a photoalignment film having a thickness of 10 nm or more and 1000 nm or less between a base film and a liquid crystal cured film.
[4] The optics according to any one of [1] to [3] above, wherein the liquid crystal cured film is a film obtained by curing at least one compound having at least one maximum absorption between wavelengths of 300 to 400 nm. Laminated body.
[5] The liquid crystal cured film has the following formula (3):
100 nm ≤ Re (550) ≤ 170 nm (3)
[In the equation, Re (λ) indicates the in-plane phase difference value at the wavelength λ]
The optical laminate according to any one of the above [1] to [4], which satisfies the above conditions.
[6] The optical laminate according to any one of [1] to [5] above, wherein the transparent protective film has a moisture permeability of 100 g / m ^2/24 hours or more.
[7] The optical laminate according to any one of [1] to [6] above, wherein the adhesive layer is a layer formed from a dry solidified adhesive.
[8] The optical laminate according to the above [7], wherein the dry solidifying adhesive contains polyvinyl alcohol.
[9] The optical laminate according to any one of [1] to [8], wherein the retardation film is in contact with an adhesive layer for bonding the retardation film and a polarizing element on the liquid crystal curing film side.
[10] An optical laminate roll formed by winding the optical laminate according to any one of the above [1] to [9].
[11] An elliptical polarizing plate including the optical laminate according to any one of the above [1] to [9].
[12] An organic EL display device including the elliptical polarizing plate according to the above [11].
[13] A flexible image display device including the elliptical polarizing plate according to the above [11].
[14] The flexible image display device according to the above [13], further including a window and a touch sensor.

According to the present invention, it is possible to provide an optical laminate that is less likely to cause distortion when bent and is excellent in high flexibility and oblique reflectance, particularly an optical laminate suitable for a flexible display.

It is a schematic sectional drawing which shows an example of the layer structure of the optical laminated body of this invention. It is a schematic sectional drawing which shows an example of the layer structure of the optical laminated body of this invention.

Hereinafter, embodiments of the present invention will be described in detail. The scope of the present invention is not limited to the embodiments described here, and various modifications can be made without impairing the gist of the present invention.

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

(Adhesive layer)
In the optical laminate of the present invention, the retardation film and the polarizing element, and the polarizing element and the transparent protective film are laminated via an adhesive layer, respectively. A liquid crystal cured film that constitutes a retardation film when the obtained optical laminate is repeatedly bent by bonding the retardation film and the polarizing element, and the polarizing element and the transparent protective film, respectively, with an adhesive layer. It is considered that the deformation in the above and the deformation of the optical laminate as a whole can easily follow each other, distortion at the bending point is unlikely to occur, and streak-like defects and an increase in oblique reflectance caused by the distortion can be suppressed. can.

The adhesive layer for adhering the retardation film and the polarizing element and the polarizing element and the transparent protective film can be formed by an adhesive. Examples of the adhesive capable of forming such an adhesive layer include a dry solidification type adhesive such as a water-based adhesive and a chemical reaction type adhesive such as an active energy ray-curable adhesive. The adhesive layer for adhering the retardation film and the polarizing element and the polarizing element and the transparent protective film may be formed of different adhesives, but is preferably formed of the same adhesive.

As the dry solidification type adhesive, for example, a polymer of a monomer having a protonic functional group such as a hydroxyl group, a carboxyl group or an amino group and an ethylenically unsaturated group, or a urethane resin is contained as a main component, and more. Examples thereof include compositions containing a cross-linking agent such as a valent aldehyde, an epoxy compound, an epoxy resin, a melamine compound, a zirconia compound, and a zinc compound, or a curable compound. Examples of the polymer of the monomer having a protonic functional group such as a hydroxyl group, a carboxyl group or an amino group and an ethylenically unsaturated group include ethylene-maleic acid copolymer, itaconic acid copolymer, acrylic acid copolymer and acrylamide. Examples thereof include a copolymer, a saponified product of polyvinyl acetate, and a polyvinyl alcohol-based resin.

Examples of the polyvinyl alcohol-based resin include polyvinyl alcohol, partially saponified polyvinyl alcohol, fully saponified polyvinyl alcohol, carboxyl group-modified polyvinyl alcohol, acetoacetyl group-modified polyvinyl alcohol, methylol group-modified polyvinyl alcohol, and amino group-modified polyvinyl alcohol. Can be mentioned. The content of the polyvinyl alcohol-based resin in the water-based dry solidifying adhesive is usually 1 to 10 parts by mass, preferably 1 to 5 parts by mass with respect to 100 parts by mass of water.

Examples of the urethane resin include polyester ionomer type urethane resin and the like.
The polyester-based ionomer type urethane resin referred to here is a urethane resin having a polyester skeleton, in which a small amount of an ionic component (hydrophilic component) is introduced. Since the ionomer type urethane resin is emulsified in water to form an emulsion without using an emulsifier, it can be used as a water-based dry solidifying adhesive. When a polyester ionomer type urethane resin is used, it is effective to add a water-soluble epoxy compound as a cross-linking agent.

Examples of the epoxy resin include a polyamide epoxy resin obtained by reacting a polyamide polyamine obtained by reacting a polyalkylene polyamine such as diethylenetriamine or triethylenetetramine with a dicarboxylic acid such as adipic acid with epichlorohydrin. Commercially available products of such polyamide epoxy resin include "Smiley's Resin (Registered Trademark) 650", "Smiley's Resin (Registered Trademark) 675" (all manufactured by Sumika Chemtex Co., Ltd.), and "WS-525" (Japan PMC). (Made by Co., Ltd.), etc. When the epoxy resin is blended, the amount added is usually 1 to 100 parts by mass, preferably 1 to 50 parts by mass with respect to 100 parts by mass of the polyvinyl alcohol-based resin.

Above all, it is preferable that the dry solidifying adhesive is a water-based dry solidifying adhesive containing a polyvinyl alcohol-based resin.

The dry solidified adhesive may contain a solvent. Examples of the solvent include water, a mixed solvent of water and a hydrophilic organic solvent (for example, an alcohol solvent, an ether solvent, an ester solvent, etc.), an organic solvent, and the like.

The active energy ray-curable adhesive, which is a chemical reaction type adhesive, is an adhesive that cures by being irradiated with active energy rays. The active energy ray-curable adhesive may contain a solvent.
Examples of the active energy ray-curable adhesive include a cationically polymerizable adhesive containing an epoxy compound and a cationic polymerization initiator, a radically polymerizable adhesive containing an acrylic curing component and a radical polymerization initiator, and an epoxy compound. It contains both a cationically polymerizable curing component such as, and a radically polymerizable curing component such as an acrylic compound, and further contains an adhesive containing a cationic polymerization initiator and a radical polymerization initiator, and these polymerization initiators. Examples thereof include an adhesive that is cured by irradiating it with an electron beam.

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

Examples of the radical polymerization initiator include photopolymerization initiators, which will be described later, which can be blended in the polymerizable liquid crystal composition forming the liquid crystal cured film. Commercially available products of cationic polymerization initiators include "Kayarad" (registered trademark) series (manufactured by Nippon Kayaku Co., Ltd.), "Syracure UVI" series (manufactured by Dow Chemical Co., Ltd.), and "CPI" series (manufactured by Sun Appro Co., Ltd.). "TAZ", "BBI" and "DTS" (above, manufactured by Midori Chemical Co., Ltd.), "ADEKA PTOMER" series (manufactured by ADEKA Corporation), "RHODORSIL" (registered trademark) (manufactured by Rhodia Co., Ltd.), etc. Be done. The content of the radical polymerization initiator and the cationic polymerization initiator is usually 0.5 to 20 parts by mass, preferably 1 to 15 parts by mass with respect to 100 parts by mass of the active energy ray-curable adhesive.

In an optical laminate in which a retardation film, a stator and a transparent protective film are laminated in this order, a pressure-sensitive pressure-sensitive adhesive formed from a highly viscous material is used from the viewpoint of reducing the thickness of the laminate and improving the flexibility. In comparison, it is considered advantageous to use an adhesive such as a dry solidification type adhesive or a chemical reaction type adhesive. On the other hand, the optical laminate of the present invention contains a liquid crystal cured film exhibiting the optical properties represented by the formulas (1) and (2) as a single layer, and the polymerizable liquid crystal compound forming such a liquid crystal cured film. Will generally have a maximum absorption wavelength between the wavelengths of 300 and 400 nm, as will be described later. Further, since the transparent protective film located on the visual recognition side when incorporated in the image display device has an ultraviolet absorbing ability to protect the internal structure of the optical laminate from ultraviolet rays, the optical laminate having such a configuration In the production of the above, the irradiated ultraviolet rays are absorbed by the liquid crystal curing film or the transparent protective film, and it may be difficult for an amount of ultraviolet rays sufficient for curing the adhesive to reach the inside of the laminate. Therefore, in the optical laminate of the present invention, which may be sandwiched between layers having an ultraviolet absorbing ability (liquid crystal curing film and transparent protective film), a retardation film and a polarizing element, and a polarizing element and a transparent protective film are attached. It is advantageous to use a dry solidification type adhesive as the adhesive for bonding, from the viewpoint of thinning and improving the flexibility, and also from the viewpoint of obtaining an optical laminate having better adhesion between the layers.

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

(Phase difference film)
The retardation film constituting the optical laminate of the present invention includes a base film having a moisture permeability of 100 g / m ^2/24 hours or more and a liquid crystal cured film formed on the base film. The moisture permeability of the base film is preferably 150 g / m ^2/24 hours or more, and more preferably 200 g / m ^2/24 hours or more. When the moisture permeability of the base film constituting the retardation film is equal to or higher than the above lower limit, the moisture content in the optical laminate formed by laminating the retardation film with the polarizing element can be easily controlled, and in particular, an adhesive. When a dry-solidified adhesive is used as the adhesive to form the layer, the solvent in the adhesive can be easily removed, and the physical properties of the liquid crystal cured film formed on the base film are close to the elasticity and flexibility. It becomes easy to prepare the adhesive layer having. Therefore, when the optical laminate is bent, the adhesive layer that adheres each layer is unlikely to affect the deformation of the liquid crystal cured film, and the deformation of the entire optical laminate and the deformation of each layer are likely to follow each other. As a result, distortion is unlikely to occur at the bending point even when repeatedly bending, and it is possible to suppress streak-like defects and an increase in oblique reflectance due to this. The upper limit of the moisture permeability of the base film is not particularly limited, but is usually 1000 g / m ^2/24 hours or less, preferably 500 g / m ^2/24 hours or less.
The moisture permeability of the base film can be measured by, for example, JIS Z 0208 (cup method). In detail, it can be measured according to the method described in Examples described later.

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

Examples of the resin constituting the base film having a moisture permeability of 100 g / m ^2/24 hours or more include triacetyl cellulose, polyvinylpyrrolidone-based polymer, (meth) acrylamide-based polymer, and the like, which are available. Triacetyl cellulose is preferable from the viewpoint of ease of use and the like. Such a resin can be formed into a film by a known means such as a solvent casting method and a melt extrusion method to obtain a base film. Further, a commercially available product may be used.

The thickness of the base film can be appropriately determined according to the desired configuration of the optical laminate, but is usually 5 μm to 300 μm from the viewpoint of thinning, processability, flexibility, strength, etc. of the optical laminate. It is preferably 15 μm to 200 μm, and more preferably 20 μm to 150 μm.

The base film has a total light transmittance of preferably 90% or more, more preferably 92% or more. When the total light transmittance is at least the above lower limit value, an optical laminate having high transparency and excellent optical characteristics can be formed. The upper limit of the total light transmittance of the base film is not particularly limited, and may be 100% or less. The total light transmittance can be measured according to, for example, JIS K7361.

The base film preferably has an absolute value of the retardation value Rth (550) in the thickness direction with respect to light of 550 nm of 5 nm or less, and more preferably 3 nm or less. By controlling the phase difference value in the thickness direction of the base film, it is difficult to affect the optical characteristics expected by the liquid crystal cured film, and the oblique reflectance of the obtained optical laminate can be suppressed to a low level. Such an optical laminate is an advantageous optical laminate in terms of optical characteristics because it is excellent in suppressing light leakage and hue change during black display when incorporated into a display device or the like. The smaller the retardation value Rth (550) of the base film is, the more preferable it is, and it may be 0 nm. The retardation value Rth (550) of the base film can be controlled not only by blending an additive but also by a casting method or the like.

The surface of the base film is treated with corona in order to improve the adhesion with the liquid crystal cured film to be formed, the components constituting the alignment film, the components of the adhesive that can come into contact with the base film, and the like. Surface treatment such as plasma treatment may be applied.

In the present invention, the liquid crystal cured film constituting the retardation film has the following formulas (1) and (2):
Re (450) / Re (550) ≤ 1.00 (1)
1.00 ≤ Re (650) / Re (550) (2)
[In the equation, Re (λ) indicates the in-plane phase difference value at the wavelength λ]
Is a liquid crystal curing film that fills with a single layer. "Filling with a single layer" means that the one-layer cured film obtained from the polymerizable liquid crystal compound containing the liquid crystal compound is a single layer and exhibits the optical characteristics represented by the above formulas (1) and (2). do.

When the liquid crystal cured film satisfies the formulas (1) and (2), the liquid crystal cured film has a so-called inverse wavelength dispersion in which the in-plane retardation value at a short wavelength is smaller than the in-plane retardation value at a long wavelength. Show sex. When the inverse wavelength dispersibility is exhibited, uniform phase difference performance tends to be exhibited in a wide wavelength range of visible light, and the optical characteristics of the optical laminate tend to be improved. By using a liquid crystal cured film having optical characteristics satisfying the above formulas (1) and (2) with a single layer (hereinafter, also referred to as "liquid crystal cured film (x)"), a thinner phase difference while having excellent optical characteristics. You can get the film.

Re (450) / Re (550) is preferably 0.70 or more, more preferably 0, because the reverse wavelength dispersibility is improved and the effect of improving the reflected hue in the front direction of the liquid crystal cured film can be further enhanced. It is .78 or more, preferably 0.95 or less, and more preferably 0.92 or less. Further, Re (650) / Re (550) is preferably 1.0 or more, more preferably 1.01 or more, and further preferably 1.02 or more.

The in-plane retardation value can be adjusted by the thickness d1 of the liquid crystal cured film. The in-plane retardation value of the cured liquid crystal film is Re = (nx (λ) -ny (λ)) × d (in the formula, d represents the thickness of the cured liquid crystal film, and nx is the refractive index formed by the cured liquid crystal film. In the rate ellipse, it represents the main refractive index at a wavelength of λ nm in the direction parallel to the plane of the cured liquid crystal film, and ny is parallel to the plane of the cured liquid crystal film in the refractive index ellipse formed by the cured liquid crystal film. And, since it is determined by the refractive index at the wavelength λ nm in the direction orthogonal to the nx direction), the three-dimensional refractive index and the film thickness d are used to obtain a desired in-plane retardation value. Should be adjusted.

Further, the liquid crystal cured film (x) has the following formula (3):
100 nm ≤ Re (550) ≤ 170 nm (3)
[In the equation, Re (λ) indicates the in-plane phase difference value at the wavelength λ]
It is preferable to satisfy. When the liquid crystal cured film (x) satisfies the formula (3), the front reflection hue at the time of black display when the optical laminate (elliptic polarizing plate) containing the liquid crystal cured film (x) is applied to the organic EL display device becomes It will be easier to improve. A more preferable range of the in-plane retardation value is 130 nm ≦ ReA (550) ≦ 150 nm.

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

The polymerizable liquid crystal compound is a liquid crystal compound having a polymerizable group. As the polymerizable liquid crystal compound, generally, the polymer (cured product) obtained by polymerizing the polymerizable liquid crystal compound alone in a state of being oriented in a specific direction is opposite to that of the polymerizable liquid crystal compound exhibiting positive wavelength dispersity. Examples thereof include polymerizable liquid crystal compounds exhibiting wavelength dispersibility. From the viewpoint that it is easy to obtain a liquid crystal cured film that independently satisfies the optical characteristics represented by the above formulas (1) and (2), the liquid crystal cured film (x) constituting the retardation film in the present invention is independently in a specific direction. It is preferable that the polymer (cured product) obtained by polymerizing in a state oriented in the above direction is a cured product of a polymerizable liquid crystal composition containing a polymerizable liquid crystal compound exhibiting reverse wavelength dispersibility.

A polymerizable group is a group that can participate in a polymerization reaction. In the present invention, the polymerizable group contained in the polymerizable liquid crystal compound forming the liquid crystal cured film is preferably a photopolymerizable group. The photopolymerizable group is a polymerizable group and refers to a group that can participate in the polymerization reaction by a reactive active species generated from the photopolymerization initiator, for example, an active radical or an acid. Examples of the photopolymerizable group include a vinyl group, a vinyloxy group, a 1-chlorovinyl group, an isopropenyl group, a 4-vinylphenyl group, an acryloyloxy group, a methacryloyloxy group, an oxylanyl group and an oxetanyl group. Of these, an acryloyloxy group, a methacryloyloxy group, a vinyloxy group, an oxylanyl group and an oxetanyl group are preferable, and an acryloyloxy group is more preferable.

The liquid crystal property exhibited by the polymerizable liquid crystal compound may be a thermotropic liquid crystal or a lyotropic liquid crystal, but the thermotropic liquid crystal is preferable in that precise film thickness control is possible. Further, the phase-ordered structure of the thermotropic liquid crystal may be a nematic liquid crystal, a smectic liquid crystal, or a discotic liquid crystal. The polymerizable liquid crystal compound can be used alone or in combination of two or more.

Polymerizable liquid crystal compounds having a so-called T-shaped or H-shaped molecular structure tend to exhibit reverse wavelength dispersibility, and polymerizable liquid crystal compounds having a T-shaped molecular structure tend to exhibit stronger reverse wavelength dispersibility. be.

The polymerizable liquid crystal compound exhibiting reverse wavelength dispersibility is preferably a compound having the following characteristics (A) to (D).
(A) A compound capable of forming a nematic phase or a smectic phase.
(B) The polymerizable liquid crystal compound has π electrons in the long axis direction (a).
(C) It has π electrons in the direction [intersection direction (b)] intersecting with respect to the major axis direction (a).
(D) A polymerizable liquid crystal compound defined by the following formula (i), where the total number of π electrons existing in the long axis direction (a) is N (πa) and the total molecular weight existing in the long axis direction is N (Aa). Π electron density in the long axis direction (a) of
D (πa) = N (πa) / N (Aa) (i)
The polymerizable liquid crystal compound defined by the following formula (ii), where the total number of π electrons existing in the crossing direction (b) is N (πb) and the total molecular weight existing in the crossing direction (b) is N (Ab). Π electron density in the crossing direction (b) of
D (πb) = N (πb) / N (Ab) (ii)
And, the formula (iii)
0 ≦ [D (πa) / D (πb)] <1 (iii)
[That is, the π electron density in the crossing direction (b) is larger than the π electron density in the major axis direction (a)]. As described above, a polymerizable liquid crystal compound having a major axis and π electrons in the crossing direction with respect to the major axis tends to have a T-shaped structure in general.

In the above features (A) to (D), the long axis direction (a) and the number of π electrons N are defined as follows.
The major axis direction (a) is, for example, the rod-shaped major axis direction in the case of a compound having a rod-shaped structure.
The number of π electrons N (πa) existing in the long axis direction (a) does not include π electrons that disappear due to the polymerization reaction.
The number of π electrons N (πa) existing in the long axis direction (a) is the total number of π electrons on the long axis and π electrons coupled thereto, for example, existing in the long axis direction (a). The number of π electrons present in the ring that satisfies Hückel's law is included.
The number of π electrons N (πb) existing in the crossing direction (b) does not include π electrons that disappear due to the polymerization reaction.
The polymerizable liquid crystal compound satisfying the above has a mesogen structure in the long axis direction. The liquid crystal phase (nematic phase, smectic phase) is expressed by this mesogen structure.

It is possible to form a nematic phase or a smectic phase by heating the polymerizable liquid crystal compound satisfying the above (A) to (D) to a phase transition temperature or higher. In the nematic phase or smectic phase formed by orienting the polymerizable liquid crystal compound, the polymerizable liquid crystal compound is usually oriented so that the major axis directions are parallel to each other, and the major axis direction is the nematic phase or smectic phase. Is the orientation direction of. When such a polymerizable liquid crystal compound is formed into a film and polymerized in a nematic phase or a smectic phase, a polymer film composed of a polymer oriented in the long axis direction (a) can be formed. .. This polymer film absorbs ultraviolet rays by π electrons in the major axis direction (a) and π electrons in the crossing direction (b). Here, the absorption maximum wavelength of ultraviolet rays absorbed by π electrons in the crossing direction (b) is defined as λbmax. λbmax is usually 300 nm to 400 nm. The density of π electrons satisfies the above equation (iii), and since the π electron density in the crossing direction (b) is larger than the π electron density in the major axis direction (a), the vibration surface in the crossing direction (b). The absorption of linearly polarized ultraviolet rays (wavelength λbmax) having a vibration plane in the long axis direction (a) is larger than the absorption of linearly polarized ultraviolet rays (wavelength λbmax) having a vibration plane. The ratio (the ratio of the absorbance in the crossing direction (b) of the linearly polarized ultraviolet rays / the absorbance in the major axis direction (a)) is, for example, more than 1.0, preferably 1.2 or more, usually 30 or less, and for example, 10 or less. Is.

In general, a polymerizable liquid crystal compound having the above characteristics often exhibits reverse wavelength dispersibility in the birefringence of the polymer when polymerized in a state of being oriented in one direction. Specifically, for example, a compound represented by the following formula (X) (hereinafter, also referred to as “polymerizable liquid crystal compound (X)”) can be mentioned.

In formula (X), Ar represents a divalent group having an aromatic group which may have a substituent. Examples of the aromatic group referred to here include the groups exemplified by (Ar-1) to (Ar-23) described later. Further, Ar may have two or more aromatic groups. The aromatic group may contain at least one or more of a nitrogen atom, an oxygen atom and a sulfur atom. When two or more aromatic groups are contained in Ar, the two or more aromatic groups may be bonded to each other by a single bond or a divalent bonding group such as -CO-O- or -O-. ..
G ¹ and G ² independently represent a divalent aromatic group or a divalent alicyclic hydrocarbon group, respectively. 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, and carbon. The carbon atom constituting the divalent aromatic group or the divalent alicyclic hydrocarbon group may be substituted with an alkoxy group, a cyano group or a nitro group of the number 1 to 4, and 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 independently single-bonded or divalent linking groups, respectively.
k and l each independently represent an integer of 0 to 3, and satisfy the relationship of 1 ≦ k + l. Here, when 2 ≦ k + l, B ¹ and B ² , G ¹ and G ² may be the same as each other or may be different from each other.
E ¹ and E ² each independently represent an alkanediyl group having 1 to 17 carbon atoms, and an alkanediyl group having 4 to 12 carbon atoms is more preferable. Further, the hydrogen atom contained in the alkanediyl group may be substituted with a halogen atom, and -CH _2- contained in the alkanediyl group is -O-, -S-, -C (= O)-. It may be replaced with.
P ¹ and P ² independently represent a polymerizable group or a hydrogen atom, and at least one is a polymerizable group.

G ¹ and G ² are each independently 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, preferably a 1,4-phenylenediyl group. , A 1,4-cyclohexanediyl group optionally substituted with at least one substituent selected from the group consisting of a halogen atom and an alkyl group having 1 to 4 carbon atoms, more preferably a methyl group substituted 1. , 4-phenylenediyl group, unsubstituted 1,4-phenylenediyl group, or unsubstituted 1,4-trans-cyclohexanediyl group, particularly preferably unsubstituted 1,4-phenylenediyl group, or no substituted It is a substituted 1,4-trans-cyclohexandiyl 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 one of G ¹ and G ² bonded to L ¹ or L ² is preferable. More preferably, it is a divalent alicyclic hydrocarbon group.

L ¹ and L ² are independent of each other, preferably single bond, alkylene group having 1 to 4 carbon atoms, -O-, -S-, -R ^a1 OR ^a2- , -R ^a3 COOR ^a4- , -R ^a5 . OCOR ^a6- , -R ^a7 OC = OOR ^a8- , -N = N-, -CR ^c = CR ^d- , or -C≡C-. Here, R ^a1 to R ^a8 each independently represent a single bond or an alkylene group having 1 to 4 carbon atoms, and R ^c and R ^d represent an alkyl group or a hydrogen atom having 1 to 4 carbon atoms. L ¹ and L ² are independent, more preferably single bonds, -OR ^a2-1- , -CH _2- , -CH ₂ CH _2- , ^{-COOR a4-1-} , or -OCOR ^a6-1- . be. Here, R ^a2-1 , R ^a4-1 , and R ^a6-1 independently represent either single bond, -CH _2- , or -CH ₂ CH _2- . L ¹ and L ² are independent, more preferably single bonds, -O-, -CH ₂ CH _2- , -COO-, -COOCH ₂ CH _2- , or -OCO-, respectively.

B ¹ and B ² are independent of each other, preferably single bond, alkylene group having 1 to 4 carbon atoms, -O-, -S-, -R ^a9 OR ^a10- , -R ^a11 COOR ^a12- , -R ^a13 . OCOR ^a14 -or-R ^a15 OC = OOR ^a16- . Here, R ^a9 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 independent, more preferably single-bonded, -OR ^a10-1- , -CH _2- , -CH ₂ CH _2- , ^{-COOR a12-1-} , or -OCOR ^a14-1- . be. Here, R ^a10-1 , R ^a12-1 , and R ^a14-1 independently represent either single bond, -CH _2- , or -CH ₂ CH _2- . B ¹ and B ² are independent, more preferably single-bonded, -O-, -CH ₂ CH _2- , -COO-, -COOCH _{2 CH 2-, -OCO-, or -OCOCH 2} _CH _2- _. be.

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 from the viewpoint of expressing reverse wavelength dispersibility. When k = 2 and l = 2, it is preferable because it has a symmetrical structure.

The polymerizable group represented by P ¹ or P ² includes 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 an oxylanyl group. , And an oxetanyl group and the like.
Of these, acryloyloxy group, methacryloyloxy group, vinyl group and vinyloxy group are preferable, and acryloyloxy group and methacryloyloxy group are 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, an anthracene ring and the like, and a benzene ring and a naphthalene ring are preferable. Examples of the aromatic heterocycle include a furan ring, a benzofuran ring, a pyrrole ring, an indole ring, a thiophene ring, a benzothiophene ring, a pyridine ring, a pyrazine ring, a pyrimidine ring, a triazole ring, a triazine ring, a pyrrolin ring, an imidazole ring, and a pyrazole ring. , Thiazole ring, benzothiazole ring, thienothiazole ring, oxazole ring, benzoxazole ring, phenanthroline ring and the like. Among them, it is preferable to have a thiazole ring, a benzothiazole ring, or a benzofuran ring, and it is more preferable to have a benzothiazole ring. When Ar contains a nitrogen atom, the nitrogen atom preferably has π electrons.

In the formula (X), the total number of π electrons N _π of the group represented by Ar is usually 6 or more, preferably 8 or more, more preferably 10 or more, still more preferably 14 or more. Especially preferably, it is 16 or more. Further, it is preferably 32 or less, more preferably 26 or less, and further preferably 24 or less.

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

In the formulas (Ar-1) to (Ar-23), * indicates a connecting part, and Z ⁰ , Z ¹ and Z ² are independently hydrogen atoms, halogen atoms, and alkyl 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 12 carbon atoms, Alkylthio group with 1-12 carbon atoms, N-alkylamino group with 1-12 carbon atoms, N, N-dialkylamino group with 2-12 carbon atoms, N-alkylsulfamoyl group with 1-12 carbon atoms or carbon Represents an N, N-dialkylsulfamoyl group of number 2-12. Further, Z ⁰ , Z ¹ and Z ² may contain a polymerizable group.

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

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

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

W ¹ and W ² 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 in 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. The aromatic heterocyclic group has 4 to 20 carbon atoms including at least one heteroatom such as a nitrogen atom such as a frill group, a pyrrolyl group, a thienyl group, a pyridinyl group, a thiazolyl group and a benzothiazolyl group, an oxygen atom and a sulfur atom. Examples thereof include an aromatic heterocyclic group, and a frill group, a thienyl group, a pyridinyl group, a thiazolyl group and a benzothiazolyl group are preferable.

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

It is preferable that Z ⁰ , Z ¹ and Z ² are independently hydrogen atom, halogen atom, alkyl group having 1 to 12 carbon atoms, cyano group, nitro group and alkoxy group having 1 to 12 carbon atoms, respectively. ⁰ is more preferably a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, and a cyano group, and Z ¹ and Z ² are further preferably a hydrogen atom, a fluorine atom, a chlorine atom, a methyl group, and a cyano group. Further, Z ⁰ , Z ¹ and Z ² may contain a polymerizable group.

Q ¹ and Q ² are preferably -NH-, -S-, -NR 2'-, and ^-O- , and R ^2'is preferably a hydrogen atom. Of these, -S-, -O-, and -NH- are particularly preferable.

Among the formulas (Ar-1) to (Ar-23), the formula (Ar-6) and the 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 attached and Z ⁰ . Examples of the aromatic heterocyclic group include those described above as the aromatic heterocycle that Ar may have. For example, a pyrrole ring, an imidazole ring, a pyrroline ring, a pyridine ring, a pyrazine ring, a pyrimidine ring, and an indole. Examples thereof include a ring, a quinoline ring, an isoquinoline ring, a purine ring, a pyrroline ring, and the like. This aromatic heterocyclic group may have a substituent. Further, Y ¹ may be a polycyclic aromatic hydrocarbon group or a polycyclic aromatic heterocyclic group which may be substituted as described above, together with the nitrogen atom to which the Y 1 is bonded and Z ⁰ . For example, a benzofuran ring, a benzothiazole ring, a benzoxazole ring and the like can be mentioned.

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

Specific examples of the polymerizable liquid crystal compound capable of forming the liquid crystal cured film (x) include polymerizable liquid crystal compounds as described in JP-A-2011-207765, JP-A-2010-031223 and the like. Be done. Further, as long as a single layer can form a liquid crystal cured film (x) satisfying the above formulas (1) and (2), a polymerizable liquid crystal compound whose homopolymer exhibits positive wavelength dispersibility may be used in an appropriate amount. ..

The content of the polymerizable liquid crystal compound in the polymerizable liquid crystal composition for forming the liquid crystal cured film (x) is, for example, 70 to 99.5 parts by mass with respect to 100 parts by mass of the solid content of the polymerizable liquid crystal composition. It is preferably 80 to 99 parts by mass, more preferably 85 to 98 parts by mass, and further preferably 90 to 95 parts by mass. When the content of the polymerizable liquid crystal compound is within the above range, it is advantageous from the viewpoint of the orientation of the obtained liquid crystal cured film (x). In addition, in this specification, the solid content of a polymerizable liquid crystal composition means all components except a volatile component such as an organic solvent from a polymerizable liquid crystal composition.

The polymerizable liquid crystal composition for forming the liquid crystal cured film (x) includes, in addition to the polymerizable liquid crystal compound, a solvent, a polymerization initiator, a leveling agent, an antioxidant, a photosensitizer, a reactive additive and the like. It may further contain an additive. As each of these components, only one kind may be used, or two or more kinds may be used in combination.

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

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

The polymerization initiator is a compound that can initiate a polymerization reaction such as a polymerizable liquid crystal compound by producing a reactive species by the contribution of heat or light. Examples of the reaction active species include active species such as radicals or cations or anions. Of these, a photopolymerization initiator that generates radicals by light irradiation is preferable from the viewpoint of easy reaction control.

Examples of the photopolymerization initiator include benzoin compounds, benzophenone compounds, benzyl ketal compounds, oxime compounds, α-hydroxyketone compounds, α-aminoketone compounds, triazine compounds, iodonium salts and sulfonium salts, and commercially available products are used. May be good. Specifically, Irgacure (registered trademark) 907, Irgacure 184, Irgacure 651, Irgacure 819, Irgacure 250, Irgacure 369, Irgacure 379, Irgacure 127, Irgacure 2959, Irgacure 754, Irgacure 379EG (above, BASF Japan) , Sakeol BZ, Sakeol Z, Sakeol BEE (manufactured by Seiko Kagaku Co., Ltd.), Kayacure BP100 (manufactured by Nippon Kayaku Co., Ltd.), Kayacure UVI-6992 (manufactured by Dow), ADEKA PTOMER SP- 152, ADEKA CORPORATION SP-170, ADEKA CORPORATION N-1717, ADEKA CORPORATION N-1919, ADEKA ARCULDS NCI-831, ADEKA ARCULDS NCI-930 (all manufactured by ADEKA Corporation), TAZ-A, TAZ -PP (above, manufactured by Nippon Sibel Hegner), TAZ-104 (manufactured by Sanwa Chemical Co., Ltd.) and the like can be mentioned.
The photopolymerization initiator contained in the polymerizable liquid crystal composition is at least one type, and a plurality of types may be used in combination, and may be appropriately selected in relation to the polymerizable liquid crystal compound contained in the polymerizable liquid crystal composition. good.

Since the photopolymerization initiator can fully utilize the energy emitted from the light source and is excellent in productivity, the maximum absorption wavelength is preferably 300 nm to 400 nm, more preferably 300 nm to 380 nm, and above all, the α-acetophenone type. A polymerization initiator and an oxime-based photopolymerization initiator are preferable.

Examples of the α-acetophenone compound include 2-methyl-2-morpholino-1- (4-methylsulfanylphenyl) propan-1-one and 2-dimethylamino-1- (4-morpholinophenyl) -2-benzylbutane-1. -On and 2-dimethylamino-1- (4-morpholinophenyl) -2- (4-methylphenylmethyl) butane-1-one and the like, more preferably 2-methyl-2-morpholino-1- ( Examples thereof include 4-methylsulfanylphenyl) propan-1-one and 2-dimethylamino-1- (4-morpholinophenyl) -2-benzylbutane-1-one. Examples of commercially available α-acetophenone compounds include Irgacure 369, 379EG, 907 (all manufactured by BASF Japan Ltd.) and Sequol BEE (manufactured by Seiko Kagaku Co., Ltd.).

The oxime ester-based photopolymerization initiator generates radicals such as phenyl radicals and methyl radicals when irradiated with light. The polymerization of the polymerizable liquid crystal compound proceeds preferably by this radical, and among them, the oxime ester-based photopolymerization initiator that generates a methyl radical is preferable because the polymerization reaction initiation efficiency is high. Further, from the viewpoint of more efficiently advancing the polymerization reaction, it is preferable to use a photopolymerization initiator capable of efficiently utilizing ultraviolet rays having a wavelength of 350 nm or more. As the photopolymerization initiator capable of efficiently utilizing ultraviolet rays having a wavelength of 350 nm or more, a triazine compound or a carbazole compound having an oxime ester structure is preferable, and a carbazole compound having an oxime ester structure is more preferable from the viewpoint of sensitivity. Examples of the carbazole compound containing an oxime ester structure include 1,2-octanedione, 1- [4- (phenylthio) -2- (O-benzoyloxime)], etanone, 1- [9-ethyl-6- (2-). Methylbenzoyl) -9H-carbazole-3-yl] -1- (O-acetyloxime) and the like can be mentioned. Commercially available products of oxime ester-based photopolymerization initiators include Irgacure OXE-01, Irgacure OXE-02, Irgacure OXE-03 (above, manufactured by BASF Japan Ltd.), ADEKA PTOMER N-1919, and ADEKA ARCULDS NCI-831. (The above is manufactured by ADEKA CORPORATION) and the like.

The content of the photopolymerization initiator is usually 0.1 to 30 parts by mass, preferably 1 to 20 parts by mass, and more preferably 1 to 15 parts by mass with respect to 100 parts by mass of the polymerizable liquid crystal compound. Is. Within the above range, the reaction of the polymerizable group proceeds sufficiently, and the orientation of the polymerizable liquid crystal compound is not easily disturbed.

The leveling agent is an additive having a function of adjusting the fluidity of the polymerizable liquid crystal composition and making the coating film obtained by applying the composition flatter. Examples thereof include silicone-based, polyacrylate-based and perfluoroalkyl-based leveling agents. Commercially available products may be used as the leveling agent, and 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 Industry Co., Ltd.), TSF400, TSF401, TSF410, TSF4300, TSF4440, TSF4445, TSF-4446, TSF4452, TSF44 (All of them are made by Momentive Performance Materials Japan GK), Florinert (registered trademark) FC-72, FC-40, FC-43, FC-3283 (All of which are made by Sumitomo 3M Co., Ltd.) ), Megafuck (registered trademark) R-08, R-30, R-90, F-410, F-411, F-443, F-445, F-470, F- 477, F-479, F-482, F-483, F-556 (all manufactured by DIC Co., Ltd.), Ftop (trade name) EF301, EF303, EF351, EF352 (all of which are manufactured by DIC Co., Ltd.) All of the above are manufactured by Mitsubishi Materials Electronics 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, E5844 (manufactured by Daikin Fine Chemical Laboratory Co., Ltd.), BM-1000, BM-1100, BYK-352, BYK-353 and BYK-361N (trade name: manufactured by BM Chemie) and the like can be mentioned. The leveling agent can be used alone or in combination of two or more.

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

By blending an antioxidant, the polymerization reaction of the polymerizable liquid crystal compound can be controlled. The antioxidant may be a primary antioxidant selected from phenol-based antioxidants, amine-based antioxidants, quinone-based antioxidants, and nitroso-based antioxidants, as well as phosphorus-based antioxidants and sulfur. It may be a secondary antioxidant selected from the system antioxidants.
In order to polymerize the polymerizable liquid crystal compound without disturbing the orientation of the polymerizable liquid crystal compound, the content of the antioxidant is usually 0.01 to 10 parts by mass with respect to 100 parts by mass of the polymerizable liquid crystal compound. Yes, preferably 0.1 to 5 parts by mass, and more preferably 0.1 to 3 parts by mass.
Antioxidants can be used alone or in combination of two or more.

By using a photosensitizer, the photopolymerization initiator can be made highly sensitive. Examples of the photosensitizer include xanthones such as xanthones and thioxanthones; anthracenes having substituents such as anthracene and alkyl ethers; phenothiazines; rubrene. The photosensitizer can be used alone or in combination of two or more. The content of the photosensitizer is usually 0.01 to 10 parts by mass, preferably 0.05 to 5 parts by mass, and more preferably 0.1 to 5 parts by mass with respect to 100 parts by mass of the polymerizable liquid crystal compound. 3 parts by mass.

By using the reaction additive, the adhesion between the base film and the liquid crystal cured film and the adhesion between the retardation film and the adhesive layer can be improved. The reactive additive preferably has a carbon-carbon unsaturated bond and an active hydrogen reactive group in the molecule. The "active hydrogen reactive group" as used herein is a group having reactivity with a group having active hydrogen such as a carboxyl group (-COOH), a hydroxyl group (-OH) and an amino group (-NH ₂ ). A typical example thereof is a glycidyl group, an oxazoline group, a carbodiimide group, an aziridine group, an imide group, an isocyanate group, a thioisocyanate group, a maleic anhydride group and the like. The number of carbon-carbon unsaturated bonds or active hydrogen reactive groups contained in the reactive additive is usually 1 to 20 each, and preferably 1 to 10 each.

It is preferable that at least two active hydrogen-reactive groups are present in the reactive additive, and in this case, the plurality of active hydrogen-reactive groups may be the same or different.

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

Specific examples of the reactive additive include compounds having a (meth) acrylic group and an epoxy group, such as methacryloxyglycidyl ether and acryloxyglycidyl ether; (meth) acrylic groups and oxetane, such as oxetan acrylate and oxetane methacrylate. Compounds with groups; Compounds with (meth) acrylic groups and lactone groups such as lactone acrylates and lactone methacrylates; Compounds with vinyl and oxazoline groups such as vinyl oxazoline and isopropenyl oxazoline; isocyanatomethyl acrylates , Isocyanatomethylmethacrylate, 2-isocyanatoethyl acrylate, 2-isocyanatoethyl methacrylate and the like, oligomers of compounds having a (meth) acrylic group and an isocyanate group. Further, examples thereof include compounds having a vinyl group, a vinylene group and an acid anhydride, such as methacrylic anhydride, acrylic acid anhydride, maleic anhydride or vinyl maleic anhydride. Among them, methacryloxyglycidyl ether, acryloxyglycidyl ether, isocyanatomethyl acrylate, isocyanatomethyl methacrylate, vinyloxazoline, 2-isocyanatoethyl acrylate, 2-isocyanatoethyl methacrylate or the above-mentioned oligomer is preferable, and isocyanatomethyl acrylate, 2-Isocyanatoethyl acrylate or the above oligomers are particularly preferred.

As the reactive additive, a commercially available product can be used as it is or after being purified as needed. Examples of commercially available products include Laromar (registered trademark) LR-9000 (manufactured by BASF).

When the polymerizable liquid crystal composition contains a reactive additive, the content of the reactive additive is usually 0.01 to 10 parts by mass, preferably 0.1 part by mass with respect to 100 parts by mass of the polymerizable liquid crystal compound. ~ 7 parts by mass.

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

The liquid crystal cured film (x) is, for example,
A coating film of a polymerizable liquid crystal composition containing at least one polymerizable liquid crystal compound is formed on a base film or an alignment film described later, the coating film is dried, and the polymerizable liquid crystal composition is formed. The process of orienting the polymerizable liquid crystal compound inside, and
It can be produced by a method including a step of polymerizing a polymerizable liquid crystal compound while maintaining an oriented state to form a liquid crystal cured film.

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

As a method of applying the polymerizable liquid crystal composition to a base film or the like, a coating method such as a spin coating method, an extrusion method, a gravure coating method, a die coating method, a bar coating method, an applicator method, or a flexo method is used for printing. Known methods such as a method can be mentioned.

Then, the solvent is removed by drying or the like to form a dry coating film. Examples of the drying method include a natural drying method, a ventilation drying method, a heat drying method and a vacuum drying method. At this time, by heating the coating film obtained from the polymerizable liquid crystal composition, the solvent is dried and removed from the coating film, and the polymerizable liquid crystal compound is oriented in a desired direction such as a horizontal direction with respect to the coating surface plane. Can be made to. The heating temperature of the coating film can be appropriately determined in consideration of the polymerizable liquid crystal compound to be used and the material of the base film or the like forming the coating film. Usually, it is necessary that the temperature is equal to or higher than the liquid crystal phase transition temperature. In order to bring the polymerizable liquid crystal compound into a desired orientation while removing the solvent contained in the polymerizable liquid crystal composition, for example, the liquid crystal phase transition temperature (smetic phase) of the polymerizable liquid crystal compound contained in the polymerizable liquid crystal composition. It can be heated to a temperature of about (transition temperature or nematic phase transition temperature) or higher. The heating temperature is preferably 3 ° C. or higher, more preferably 5 ° C. or higher, higher than the liquid crystal phase transition temperature of the polymerizable liquid crystal compound. The upper limit of the heating temperature is not particularly limited, but is preferably 180 ° C. or lower, more preferably 150 ° C. or lower in order to avoid damage to the coating film, the base film, or the like due to heating.
The liquid crystal phase transition temperature can be measured using, for example, a polarizing microscope equipped with a temperature control stage, a differential scanning calorimeter (DSC), a thermal weight differential thermal analyzer (TG-DTA), or the like. When two or more kinds of the polymerizable liquid crystal compound are used in combination, the phase transition temperature is a polymerization in which all the polymerizable liquid crystal compounds constituting the polymerizable liquid crystal composition are mixed at the same ratio as the composition in the polymerizable liquid crystal composition. It means a temperature measured in the same manner as when one kind of polymerizable liquid crystal compound is used by using a mixture of sex liquid crystal compounds. Further, it is generally known that the liquid crystal phase transition temperature of the polymerizable liquid crystal compound in the polymerizable liquid crystal composition may be lower than the liquid crystal phase transition temperature of the polymerizable liquid crystal compound as a single substance.

The heating time can be appropriately determined depending on the heating temperature, the type of the polymerizable liquid crystal compound used, the type of the solvent, its boiling point and its amount, etc., but is usually 0.5 to 10 minutes, preferably 0.5. ~ 5 minutes.

The solvent may be removed from the coating film at the same time as heating the polymerizable liquid crystal compound to the liquid crystal phase transition temperature or higher, or separately, but it is preferable to perform the removal at the same time from the viewpoint of improving productivity. Before heating the polymerizable liquid crystal compound to a temperature higher than the liquid crystal phase transition temperature, the solvent in the coating film should be appropriately added under the condition that the polymerizable liquid crystal compound contained in the coating film obtained from the polymerizable liquid crystal composition does not polymerize. A pre-drying step may be provided for removal. Examples of the drying method in the pre-drying step include a natural drying method, a ventilation drying method, a heating drying method and a vacuum drying method, and the drying temperature (heating temperature) in the drying step is the type of polymerizable liquid crystal compound to be used and the solvent. It can be appropriately determined according to the type of the above, its boiling point, its amount and the like.

Next, in the obtained dry coating film, the polymerizable liquid crystal compound is polymerized by light irradiation while maintaining the orientation state of the polymerizable liquid crystal compound, whereby the polymer of the polymerizable liquid crystal compound existing in the desired orientation state is used. A certain liquid crystal cured film is formed. As the polymerization method, a photopolymerization method is usually used. In photopolymerization, the light irradiating the dry coating film includes the type of the photopolymerization initiator contained in the dry coating film and the type of the polymerizable liquid crystal compound (particularly, the type of the polymerizable group of the polymerizable liquid crystal compound). And it is appropriately selected according to the amount. Specific examples thereof include one or more types of light selected from the group consisting of visible light, ultraviolet light, infrared light, X-rays, α-rays, β-rays and γ-rays, and active energy rays such as active electron beams. Will be. Among them, ultraviolet light is preferable because it is easy to control the progress of the polymerization reaction and it is possible to use a photopolymerization apparatus widely used in the art, so that photopolymerization can be performed by ultraviolet light. It is preferable to select the type of the polymerizable liquid crystal compound or the photopolymerization initiator contained in the polymerizable liquid crystal composition. Further, at the time of polymerization, the polymerization temperature can be controlled by irradiating light while cooling the dry coating film by an appropriate cooling means. By adopting such a cooling means, if the polymerizable liquid crystal compound is polymerized at a lower temperature, a liquid crystal cured film can be appropriately formed even if a substrate having a relatively low heat resistance is used. It is also possible to promote the polymerization reaction by raising the polymerization temperature within a range in which defects due to heat during light irradiation (deformation due to heat of the base film, etc.) do not occur. A patterned cured film can also be obtained by masking or developing during photopolymerization.

Examples of the light source of the active energy ray include a low pressure mercury lamp, a medium pressure mercury lamp, a high pressure mercury lamp, an ultrahigh pressure mercury lamp, a xenon lamp, a halogen lamp, a carbon arc lamp, a tungsten lamp, a gallium lamp, an excima laser, and a wavelength range. Examples thereof include LED light sources that emit light of 380 to 440 nm, chemical lamps, black light lamps, microwave-excited mercury lamps, metal halide lamps, and the like.

The ultraviolet irradiation intensity is usually 10 to 3,000 mW / cm ² . The ultraviolet irradiation intensity is preferably an intensity in a wavelength region effective for activating the photopolymerization initiator. The time for irradiating light is usually 0.1 seconds to 10 minutes, preferably 0.1 seconds to 5 minutes, more preferably 0.1 seconds to 3 minutes, still more preferably 0.1 seconds to 1 minute. be. When irradiated once or multiple times with such an ultraviolet irradiation intensity, the integrated light amount is 10 to 3,000 mJ / cm ² , preferably 50 to 2,000 mJ / cm ² , and more preferably 100 to 1,000 mJ / cm. It is ² .

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

The liquid crystal cured film (x) may be formed on the alignment film. The alignment film has an orientation-regulating force that orients the polymerizable liquid crystal compound in a desired direction. A polymerizable liquid crystal compound is formed by forming a liquid crystal cured film using a horizontally oriented film having an orientation restricting force for orienting a polymerizable liquid crystal compound in the horizontal direction and a vertically oriented film having an orientation restricting force for orienting the polymerizable liquid crystal compound in the vertical direction. Can be oriented with higher accuracy in a desired direction, and a liquid crystal cured film showing excellent optical characteristics can be obtained when incorporated into a display device or the like. The alignment control force can be arbitrarily adjusted according to the type of alignment film, surface condition, rubbing conditions, etc., and when the alignment film is formed of a photo-alignable polymer, it can be arbitrarily adjusted according to the polarization irradiation conditions, etc. It is possible to do.

The alignment film preferably has solvent resistance that does not dissolve when the polymerizable liquid crystal composition is applied, and also has heat resistance in heat treatment for removing the solvent and aligning the polymerizable liquid crystal compound. Examples of the alignment film include an alignment film containing an orientation polymer, a photoalignment film, a grub alignment film having an uneven pattern or a plurality of grooves on the surface, a stretched film stretched in the orientation direction, and the like, and the accuracy of the alignment angle and From the viewpoint of quality, a photoalignment film is preferable.

Examples of the oriented polymer include polyamides and gelatins having an amide bond in the molecule, polyimide having an imide bond in the molecule and its hydrolyzate polyamic acid, polyvinyl alcohol, alkyl-modified polyvinyl alcohol, polyacrylamide, and poly. Examples thereof include oxazol, polyethyleneimine, polystyrene, polyvinylpyrrolidone, polyacrylic acid and polyacrylic acid esters. Of these, polyvinyl alcohol is preferable. The oriented polymer can be used alone or in combination of two or more.

The alignment film containing the alignment polymer is usually formed by applying a composition in which the alignment polymer is dissolved in a solvent (hereinafter, also referred to as “orientation polymer composition”) to a surface such as a base film on which the alignment film should be formed. , The solvent is removed, or the oriented polymer composition is applied to the substrate, the solvent is removed, and rubbing is performed (rubbing method). Examples of the solvent include the same solvents as those exemplified above as the solvents that can be used in the polymerizable liquid crystal composition.

The concentration of the oriented polymer in the oriented polymer composition may be in the range where the oriented polymer material can be completely dissolved in the solvent, but is preferably 0.1 to 20% in terms of solid content with respect to the solution, and is 0. .1 to 10% is more preferable.

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

Examples of the method of applying the oriented polymer composition to the surface of the base film or the like on which the oriented film should be formed include the same methods as those exemplified as the method of applying the polymerizable liquid crystal composition to the base film.

Examples of the method for removing the solvent contained in the oriented polymer composition include a natural drying method, a ventilation drying method, a heat drying method and a vacuum drying method.

A rubbing process can be performed as needed to impart an orientation regulating force to the alignment film (rubbing method). As a method of imparting an orientation restricting force by the rubbing method, a rubbing cloth is wound and formed on the surface of a base material by applying an orientation polymer composition to a base material and annealing it on a rotating rubbing roll. Examples thereof include a method of contacting a film of an oriented polymer. If masking is performed during the rubbing process, it is possible to form a plurality of regions (patterns) having different orientation directions on the alignment film.

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

A photoreactive group is a group that produces a liquid crystal alignment ability when irradiated with light. Specific examples thereof include groups involved in photoreactions that are the origin of liquid crystal alignment ability such as molecular orientation induction or isomerization reaction, dimerization reaction, photocrosslinking reaction or photodecomposition reaction generated by light irradiation. Of these, groups involved in the dimerization reaction or the photocrosslinking reaction are preferable because they have excellent orientation. As the photoreactive group, an unsaturated bond, particularly a group having a double bond is preferable, and a carbon-carbon double bond (C = C bond), a carbon-nitrogen double bond (C = N bond), and a nitrogen-nitrogen double bond are preferable. Groups having at least one selected from the group consisting of double bonds (N = N bonds) and carbon-oxygen double bonds (C = O bonds) are particularly preferred.

Examples of the photoreactive group having a C = C bond include a vinyl group, a polyene group, a stilbene group, a stilbazole group, a stilbazollium group, a chalcone group, a cinnamoyl group and the like.
Examples of the photoreactive group having a C = N bond include a group having a structure such as an aromatic Schiff base and an aromatic hydrazone. Examples of the photoreactive group having an N = N bond include an azobenzene group, an azonaphthalene group, an aromatic heterocyclic azo group, a bisazo group, a formazan group, and a group having an azoxybenzene structure. Examples of the photoreactive group having a C = O bond include a benzophenone group, a coumarin group, an anthraquinone group, a maleimide group and the like. These groups may have a substituent such as an alkyl group, an alkoxy group, an aryl group, an allyloxy group, a cyano group, an alkoxycarbonyl group, a hydroxyl group, a sulfonic acid group and an alkyl halide group.

Above all, a photoreactive group involved in the photodimerization reaction is preferable, and a photoalignment film having a relatively small amount of polarization irradiation required for photoalignment and excellent thermal stability and temporal stability can be easily obtained. The photoreactive group is preferably a cinnamoyl group or a chalcone group. In particular, when the liquid crystal cured film is formed from a polymerizable liquid crystal compound having a (meth) acryloyloxy group as a polymerizable group, the end of the polymer side chain is cinnamic acid as a polymer having a photoreactive group forming an alignment film. Adhesion to the liquid crystal cured film can be improved by using a polymer having a cinnamoyl group having a structure.

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

The content of the polymer or monomer having a photoreactive group in the composition for forming a photo-alignment film can be appropriately adjusted depending on the type of the polymer or monomer and the thickness of the target photo-alignment film, but the composition for forming a photo-alignment film. It is preferably at least 0.2% by mass, more preferably in the range of 0.3 to 10% by mass, based on the mass of the above. The composition for forming a photoalignment film may contain a polymer material such as polyvinyl alcohol or polyimide or a photosensitizer as long as the characteristics of the photoalignment film are not significantly impaired.

As a method of applying the composition for forming a photoalignment film to the surface on which the alignment film should be formed, the same method as the method of applying the alignment polymer composition can be mentioned. Examples of the method for removing the solvent from the applied composition for forming a photoalignment film include a natural drying method, a ventilation drying method, a heat drying method and a vacuum drying method.

In order to irradiate the polarized light, even in the form of directly irradiating the light-aligned film-forming composition coated on the substrate film with the polarized UV removed from the composition, the substrate film side is irradiated with the polarized light to obtain the polarized light. It may be in the form of transmitting and irradiating. Further, it is particularly preferable that the polarized light is substantially parallel light. The wavelength of the polarized light to be irradiated is preferably in the wavelength range in which the photoreactive group of the polymer or monomer having a photoreactive group can absorb light energy. Specifically, UV (ultraviolet rays) having a wavelength in the range of 250 to 400 nm is particularly preferable. Examples of the light source used for the polarized light irradiation include xenon lamps, high-pressure mercury lamps, ultra-high pressure mercury lamps, metal halide lamps, ultraviolet light lasers such as KrF and ArF, and high-pressure mercury lamps, ultra-high pressure mercury lamps and metal halide lamps. preferable. Among these, a high-pressure mercury lamp, an ultra-high pressure mercury lamp, and a metal halide lamp are preferable because they have a high emission intensity of ultraviolet rays having a wavelength of 313 nm. Polarized UV can be irradiated by irradiating the light from the light source through an appropriate polarizing element. As such a polarizing element, a polarizing filter, a polarizing prism such as Gran Thomson or Gran Tailor, or a wire grid type polarizing element can be used.

If masking is performed when rubbing or irradiating with polarized light, it is possible to form a plurality of regions (patterns) in which the directions of liquid crystal orientation are different.

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

As a method of obtaining a grub alignment film, a method of forming an uneven pattern by performing exposure and rinsing treatment after exposure through an exposure mask having a pattern-shaped slit on the surface of the photosensitive polyimide film, and a plate having a groove on the surface. A method in which a layer of UV-curable resin before curing is formed on a master, and the formed resin layer is transferred to a substrate or the like and then cured, and UV before curing formed on the surface on which an alignment film should be formed. Examples thereof include a method in which a roll-shaped master having a plurality of grooves is pressed against a film of a cured resin to form irregularities, and then the film is cured.

The thickness of the alignment film (alignment film containing an alignment polymer or photoalignment film) is usually in the range of 10 nm or more and 10,000 nm or less, preferably in the range of 10 nm or more and 2500 nm or less, and more preferably in the range of 10 nm or more and 1000 nm or less. It is more preferably 10 nm or more and 500 nm or less, and particularly preferably 50 nm or more and 250 nm or less.

(Polarizer)
The polarizing element constituting the optical laminate of the present invention is a film having a function of extracting linearly polarized light from incident natural light, and is a polyvinyl alcohol-based resin film containing a dichroic dye. As the polyvinyl alcohol-based resin constituting the polyvinyl alcohol-based resin film, a saponified product of the polyvinyl acetate-based resin can be used. Examples of the polyvinyl acetate-based resin include polyvinyl acetate, which is a homopolymer of vinyl acetate, and a copolymer of vinyl acetate and another monomer copolymerizable therewith (for example, ethylene-vinyl acetate copolymer weight). Coalescence, etc.).
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-based resin is usually about 85 to 100 mol%, 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 also be used. The degree of polymerization of the polyvinyl alcohol-based resin is usually about 1,000 to 10,000, preferably in the range of 1,500 to 5,000.

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

The modulator is usually a step of uniaxially stretching such a polyvinyl alcohol-based resin film, a step of adsorbing a dichroic dye by dyeing the polyvinyl alcohol-based resin film with a dichroic dye, and a dichroic dye. It is produced through a step of treating the adsorbed polyvinyl alcohol-based resin film with an aqueous boric acid solution and a step of washing with water after the treatment with the aqueous boric acid solution. By dyeing the polyvinyl alcohol-based resin film with the dichroic dye, the dichroic dye is contained in the polyvinyl alcohol-based resin film. When the polarizing element is produced by such a production method, the polarizing element becomes a stretched polyvinyl alcohol-based resin film containing a dichroic dye.

The uniaxial stretching of the polyvinyl alcohol-based resin film may be performed before dyeing the dichroic dye, at the same time as dyeing, or after dyeing. If the uniaxial stretching is performed after staining, the uniaxial stretching may be performed before the boric acid treatment or during the boric acid treatment. It is also possible to perform uniaxial stretching at these multiple stages. In uniaxial stretching, rolls having different peripheral speeds may be uniaxially stretched, or may be uniaxially stretched using a thermal roll. Further, the uniaxial stretching may be a dry stretching performed in the atmosphere, or may be a wet stretching performed in a state where the polyvinyl alcohol-based resin film is swollen using a solvent. The draw ratio is preferably 8 times or less, more preferably 7.5 times or less, still more preferably 7 times or less, from the viewpoint of suppressing deformation of the stator. Further, the draw ratio is usually 4.5 times or more from the viewpoint of expressing the function as a polarizing element. By setting the draw ratio within the above range, it is possible to suppress the deformation of the polarizing element over time.

As a method of dyeing a polyvinyl alcohol-based resin film with a dichroic dye, for example, a method of immersing the polyvinyl alcohol-based resin film in an aqueous solution containing a dichroic dye can be mentioned. As the dichroic dye, for example, iodine or a dichroic dye is used. For dichroic dyes, for example, C.I. I. A dichroic direct dye composed of a disazo compound such as DIRECT RED 39 and a dichroic direct dye composed of a trisazo or a tetrakisazo compound are included. The polyvinyl alcohol-based resin film is preferably immersed in water before the dyeing treatment.

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

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

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

The polyvinyl alcohol-based resin film after the boric acid treatment is usually washed with water. The water washing treatment can be performed, for example, by immersing the boric acid-treated polyvinyl alcohol-based resin film in water. The temperature of water in the washing treatment is usually about 5 to 40 ° C.
The immersion time is usually about 1 to 120 seconds.

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

Thus, the polyvinyl alcohol-based resin film is obtained by uniaxial stretching, dyeing with a dichroic dye, boric acid treatment, washing with water and drying.

The thickness of the splitter is preferably 5 to 40 μm, more preferably 5 to 20 μm.

(Transparent protective film)
The optical laminate of the present invention includes a transparent protective film bonded to the surface of the stator opposite to the retardation film via an adhesive layer. Since the polarizing element has a thin film thickness and its surface is easily damaged, it is usually provided with protective films on both sides of the polarizing element in order to prevent external damage and stains. However, the optics of the present invention are provided. In the laminated body, the protective film is not laminated on the surface of the polarizing element on the retardation film side. This can result in an optical laminate that is thinner and has lower oblique reflectance.

In the present invention, the transparent protective film has a total light transmittance of 90% or more, more preferably 92% or more. When the total light transmittance is at least the above lower limit value, an optical laminate having high transparency and excellent optical characteristics can be formed. The upper limit of the total light transmittance of the base film is not particularly limited, and may be 100% or less. The total light transmittance can be measured according to, for example, JIS K7361.

Further, the 380 nm transmittance of the transparent protective film is 30% or less, preferably 25% or less, and more preferably 20% or less. When the 380 nm transmittance of the transparent protective film is not more than the above upper limit, the inside of the optical laminate is formed from the ultraviolet rays exposed on the visual recognition side when the optical laminate containing the transparent protective film is incorporated into the image display device. The layer (polarizer, cured liquid crystal film, etc.) can be protected. The lower limit of the 380 nm transmittance of the transparent protective film is not particularly limited and may be 0%. In order to reduce the 380 nm transmittance of the transparent protective film to 30% or less, the transparent protective film may contain an ultraviolet absorber or the like. The 380 nm transmittance can be measured, for example, according to a spectrophotometer.

As the transparent protective film bonded to the polarizing element via the adhesive layer, a known resin film can be used as long as it satisfies the above-mentioned total light transmittance and 380 nm transmittance. Resins that can constitute the transparent protective film include, for example, polyolefins such as polyethylene, polypropylene, and norbornene-based polymers; cyclic olefin-based resins; polyvinyl alcohol; polyethylene terephthalates; polymethacrylic acid esters; polyacrylic acid esters; triacetyl cellulose. , Diacetyl cellulose, and cellulose esters such as cellulose acetate propionate; polyethylene naphthalate; polycarbonate; polysulfone; polyethersulfone; polyetherketone; polyphenylene sulfide and polyphenylene oxide and the like. Such a resin can be formed into a film by a known means such as a solvent casting method and a melt extrusion method. The surface of the transparent protective film may be subjected to surface treatment such as mold release treatment such as silicone treatment, corona treatment, and plasma treatment.

In one embodiment of the present invention, the transparent protective film preferably has a moisture permeability of 100 g / m ^2/24 hours or more, more preferably 150 g / m ^2/24 hours or more, and further preferably 200 g / m ^2/24 hours or more. Have. When the moisture permeability of the transparent protective film is equal to or higher than the above lower limit, a group constituting the retardation film is formed when the retardation film and the polarizing element are laminated by using a dry solidifying adhesive to form an optical laminate. The solvent in the dry solidified adhesive can be efficiently removed from the transparent protective film in addition to the material film. As a result, the deformation of the liquid crystal cured film formed on the base film when bent and the deformation of the optical laminate easily follow each other, and even when repeatedly bent, distortion occurs at the bending point. A difficult optical laminate can be obtained. In addition, the time for removing the solvent in the adhesive can be shortened as compared with the case where only the base film has a high moisture permeability, which may be advantageous in terms of productivity. The upper limit of the moisture permeability of the transparent protective film is not particularly limited, but is usually 1000 g / m ^2/24 hours or less, preferably 500 g / m ^2/24 hours or less. The moisture permeability of the transparent protective film can be measured by the same method as that of the base film.

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

The thickness of the transparent protective film can be appropriately determined according to the desired configuration of the optical laminate, but is usually 5 μm to 300 μm from the viewpoint of thinning, processability, flexibility, strength, etc. of the optical laminate. It is preferably 20 μm to 200 μm, and more preferably 20 μm to 150 μm.

Hereinafter, an example of the layer structure of the optical laminate of the present invention will be described with reference to FIGS. 1 and 2, but the optical laminate of the present invention is not limited to these aspects.
The optical laminate 100 shown in FIG. 1 includes a retardation film 1, a polarizing element 3 laminated on one surface of the retardation film via an adhesive layer 2, and a retardation film 1 of the substituent 3. It is composed of a transparent protective film 5 laminated on the surface opposite to the above with an adhesive layer 4 interposed therebetween. In the optical laminate 100 shown in FIG. 1, the retardation film 1 is composed of a liquid crystal curing film 13 formed on a base film 11 via an alignment film 12.

The optical laminate of the present invention includes a retardation film, a polarizing element, a transparent protective film, and an adhesive layer for adhering them to each other, as well as other layers having various functions that can be incorporated into an image display device or the like. Although it may be included, no other layer is incorporated into the layer structure of the retardation film / adhesive layer / polarizing element / adhesive layer / transparent protective film which is adjacent to each other. Other layers include, for example, an adhesive layer for incorporating an optical laminate into an image display device, for example, a liquid crystal cured film (x) such that the liquid crystal compound is oriented in a direction perpendicular to the film surface. Examples thereof include a second retardation film containing a liquid crystal cured film having different optical characteristics.

In the present invention, the retardation film may be laminated on either side of the base film or the liquid crystal cured film constituting the retardation film via a polarizing element and an adhesive layer. For example, in the optical laminate 100 shown in FIG. 1, the base film 11 constituting the retardation film 1 is laminated with the polarizing element 3 via the adhesive layer 2. On the other hand, in the optical laminate 100 shown in FIG. 2, the liquid crystal cured film 13 constituting the retardation film 1 is laminated with the polarizing element 3 via the adhesive layer 2.

When the optical laminate of the present invention is incorporated into an image display device or the like, the liquid crystal cured film (x) constituting the retardation film adheres to the optical laminate and a member constituting the image display device such as an image display cell. When it is not in contact with the pressure-sensitive adhesive layer, the heat resistance of the optical laminate tends to be improved. Therefore, in one embodiment of the present invention, it is preferable that the retardation film is in contact with the adhesive layer that adheres the retardation film and the polarizing element on the liquid crystal cured film side constituting the retardation film.

The optical laminate of the present invention can be manufactured by laminating a retardation film, a polarizing element, and a transparent protective film, respectively, via an adhesive. When a dry-solidified adhesive is used as the adhesive, the dry-solidified adhesive is applied / injected onto the bonded surface of the retardation film, the stator and / or the transparent protective film, and the retardation film / adhesive layer / After forming a laminate of a decoder / adhesive layer / transparent protective film, each layer can be bonded by drying, removing, and curing the solvent in the adhesive from the laminate.

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

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

The light irradiation intensity to the active energy ray-curable adhesive is appropriately determined by the composition of the active energy ray-curable adhesive and is not particularly limited, but the irradiation intensity in the wavelength region effective for activating the polymerization initiator is usually set. It is 10 to 3,000 mW / cm ² . The light irradiation time of the active energy ray-curable adhesive may be appropriately selected depending on the active energy ray-curable adhesive to be cured, and is not particularly limited, but is usually 0.1 seconds to 10 minutes. It is preferably 1 second to 5 minutes, more preferably 5 seconds to 3 minutes, and even more preferably 10 seconds to 1 minute. When irradiated once or multiple times with such an ultraviolet irradiation intensity, the integrated light amount is usually 10 to 3,000 mJ / cm ² , preferably 50 to 2,000 mJ / cm ² , and more preferably 100 to 1,000 mJ /. It is cm ² .

The optical laminate of the present invention can be continuously manufactured by the Roll to Roll method. For example, a retardation film containing a base film wound in a roll shape and a liquid crystal cured film (x) is produced, and the retardation film is unwound and conveyed to provide an adhesive for adhering each layer. It can be continuously produced by laminating a separately prepared polarizing element and a transparent protective film on the retardation film in order and then curing the adhesive by drying, photocuring or the like.
Therefore, in one embodiment of the present invention, the optical laminate of the present invention may be in the form of an optical laminate roll wound in a roll shape.

Since the optical laminate of the present invention including the retardation film and the polarizing element can also be an elliptical polarizing plate, the present invention includes an elliptical polarizing plate including the optical laminate of the present invention.

In one embodiment of the present invention, the angle formed by the slow axis (optical axis) of the liquid crystal cured film constituting the optical laminate and the elliptical polarizing plate of the present invention and the absorption axis of the substituent is 45 ± 5 °. It is preferable to stack them in such a manner.

The elliptical polarizing plate of the present invention can be used in various display devices.
The display device is a device having a display element, and includes a light emitting element or a light emitting device as a light emitting source. Display devices include a liquid crystal display device, an organic electroluminescence (EL) display device, an inorganic electroluminescence (EL) display device, a touch panel display device, an electron emission display device (for example, an electric field emission display device (FED), a surface electric field emission display device). (SED)), electronic paper (display device using electronic ink or electrophoretic element, plasma display device, projection type display device (for example, grating light valve (GLV) display device, display device having a digital micromirror device (DMD)). ) And piezoelectric ceramic displays. The liquid crystal display device includes any of a transmissive liquid crystal display device, a semi-transmissive liquid crystal display device, a reflective liquid crystal display device, a direct-view type liquid crystal display device, a projection type liquid crystal display device, and the like. These display devices may be display devices for displaying two-dimensional images or three-dimensional display devices for displaying three-dimensional images. In particular, the elliptical polarizing plate of the present invention may be an organic electroluminescence (organic electroluminescence). It can be suitably used for an EL) display device and an inorganic electroluminescence (EL) display device, and the laminate of the present invention can be suitably used for a liquid crystal display device and a touch panel display device. These display devices have interference unevenness. By providing the laminated body of the present invention in which the above is unlikely to occur, good image display characteristics can be exhibited.

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

The flexible image display device having the elliptical polarizing plate of the present invention preferably further has a window and a touch sensor.
The flexible image display device is composed of, for example, a laminated body for a flexible image display device and an organic EL display panel, and the laminated body for the flexible image display device is arranged on the visual side with respect to the organic EL display panel and is configured to be bendable. Has been done. The laminated body for a flexible image display device may include a window, a (touch panel) touch sensor, and the like, in addition to the above-mentioned elliptical polarizing plate of the present invention. The stacking order thereof is arbitrary, but it is preferable that the windows, the elliptical polarizing plate, and the touch sensor are laminated in this order from the visual side, or the window, the touch sensor, and the elliptical polarizing plate are stacked in this order.

It is preferable that the elliptical polarizing plate is present on the visual side of the touch sensor because the pattern of the touch sensor is difficult to be visually recognized and the visibility of the displayed image is improved. Each member can be laminated using an adhesive, an adhesive, or the like. Further, the laminated body for a flexible image display device can be provided with a light-shielding pattern formed on at least one surface of any one of the windows, the elliptical polarizing plate, and the touch sensor.

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

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

Hereinafter, the present invention will be described more specifically by way of examples. In addition, "%" and "part" in an example mean mass% and mass part, respectively, unless otherwise specified.

[Example 1]
(1) Preparation of composition for forming a photoalignment film A polymer (1) having a number average molecular weight of 28,000 represented by the following chemical formula was mixed with 98 parts of o-xylene, and the obtained mixture was mixed at 80 ° C. for 1 hour. By stirring, a composition for forming a photoalignment film was obtained.

Polymer (1)

[In the formula, Me represents a methyl group. ]

(2) Preparation of polymerizable liquid crystal composition for forming a liquid crystal cured film A polymerizable liquid crystal compound A-1 (86.0 parts) having the following structure, a polymerizable liquid crystal compound A-2 (14.0 parts), and poly Acrylate compound (leveling agent / BYK-361N; manufactured by BYK-Chemie) (0.12 part) and 2-dimethylamino-2-benzyl-1- (4-morpholinophenyl) butane-1-one (photopolymerization started) Agent / Irgacure 369; Ciba Specialty Chemicals (manufactured by 3.0 parts) and LALOMER LR9000 (manufactured by BASF Japan) (2.0 parts) were mixed. Further, anisole was added so that the solid content concentration was 9%. A polymerizable liquid crystal composition (A1) containing the polymerizable liquid crystal compound A-1 and the polymerizable liquid crystal compound A-2 was obtained.
The polymerizable liquid crystal compound A-1 was synthesized by the method described in JP-A-2010-31223. The maximum absorption wavelength λmax (LC) of the polymerizable liquid crystal compound A-1 measured in chloroform was 350 nm.

Polymerizable liquid crystal compound A-1:

Polymerizable liquid crystal compound A-2:

(3) Preparation of retardation film A triacetyl cellulose film (KC4CZ-TAC manufactured by Konica Minolta Co., Ltd., thickness 40 μm) is treated with a corona treatment device (AGF-B10; manufactured by Kasuga Electric Works Ltd.) at an output of 0.3 kW. The treatment was performed once under the condition of a speed of 3 m / min. The composition for forming a photoalignment film was coated on the corona-treated surface with a bar coater, dried at 80 ° C. for 1 minute, and then subjected to a polarized UV irradiation device (SPOT CURE SP-7 with a polarizing element unit; manufactured by Ushio Denki Co., Ltd.). ) Was used to perform polarized UV exposure with an integrated light amount of 100 mJ / cm ² , and a photoalignment film was formed. The thickness of the obtained photoalignment film was measured with an ellipsometer M-220 (manufactured by JASCO Corporation) and found to be 100 nm.

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

(Measurement of total light transmittance)
The total light transmittance was measured using a haze meter HM150 manufactured by Murakami Color Technology Research Institute Co., Ltd. in accordance with JIS K7361. The total light transmittance of the TAC film was 93%.

Further, when the phase difference value [Re (550) and Rth (550)] of the above-mentioned TAC film as a base material at a wavelength of 550 nm was measured, it was approximately 0.

Subsequently, the polymerizable liquid crystal composition (A1) containing the polymerizable liquid crystal compound prepared above was applied onto the photoalignment film with a bar coater, and dried at 120 ° C. for 1 minute. Then, using a high-pressure mercury lamp (Unicure VB-15201BY-A; manufactured by Ushio Denki Co., Ltd.), ultraviolet rays are irradiated from the surface side coated with the polymerizable liquid crystal composition (A1) (integrated light amount at a wavelength of 313 nm under a nitrogen atmosphere). : 500 mJ / cm ² ) to form a retardation film which is a laminate composed of a triacetyl cellulose film (base film) / photoalignment film / liquid crystal cured film. The thickness of the obtained liquid crystal cured film was measured with a laser microscope (LEXT; manufactured by Olympus Corporation) and found to be 2.3 μm.

When the retardation value of the obtained retardation film at a wavelength of 550 nm was measured, it was Re (550) = 140 nm. Further, when the retardation values of the obtained retardation film at a wavelength of 450 nm and a wavelength of 650 nm were measured, Re (450) / Re (550) = 0.85 and Re (650) / Re (550) = 1.05. Met.

(4) Fabrication of modulator (iodine PVA type deflector)
A 30 μm-thick polyvinyl alcohol film (PVA: average degree of polymerization of about 2400, saponification degree of 99.9 mol% or more) was uniaxially stretched about 5 times by dry stretching, and further uniaxially stretched at 40 ° C. while maintaining a tense state. Soaked in pure water for 40 seconds. Then, the dyeing treatment was carried out by immersing the dyeing solution in a dyeing aqueous solution having an iodine / potassium iodide / water mass ratio of 0.044 / 5.7 / 100 at 28 ° C. for 30 seconds. Next, it was immersed in a boric acid aqueous solution having a mass ratio of potassium iodide / boric acid / water of 11.0 / 6.2 / 100 at 70 ° C. for 120 seconds. Subsequently, after washing with pure water at 8 ° C. for 15 seconds, while holding at a tension of 300 N, the iodine was adsorbed and oriented on the polyvinyl alcohol film by drying at 60 ° C. for 50 seconds and then at 75 ° C. for 20 seconds. A polarizing element having a thickness of 12 μm was obtained.

(5) Preparation of Optical Laminate A retardation film and a polarizing element produced above, and a triacetyl cellulose film (TAC: "KC4UY" manufactured by Konica Minolta Opto Co., Ltd.) as a transparent protective film are laminated in this order, and described above. A water-based dry solidifying adhesive is injected so that the triacetyl cellulose side of the retardation film and the polarizing element are in contact with the triacetyl cellulose side of the transparent protective film and the triacetyl cellulose side of the transparent protective film is in contact with the retarder on the opposite side of the retarder film. It was bonded with a nip roll so that the absorption axis of the child and the slow axis of the liquid crystal cured film in the retardation film were 45 °. While maintaining the tension of the obtained laminate at 430 N / m, it is dried at 60 ° C. for 2 minutes to protect the liquid crystal cured film / optical alignment film / base film / adhesive layer / polarizing element / adhesive layer / transparent protection. An optical laminate I (elliptic polarizing plate) made of a film was obtained.
The above-mentioned water-based dry solidifying adhesive contains 100 parts of water, 3 parts of carboxyl group-modified polyvinyl alcohol (Kuraray Poval KL318; manufactured by Kuraray Co., Ltd.), and a water-soluble polyamide epoxy resin (Smiley's resin 650; Sumika Chemtex). Prepared by adding 1.5 parts (an aqueous solution having a solid content concentration of 30%) manufactured by Kuraray Co., Ltd.

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

Further, the 380 nm transmittance of the transparent protective film was measured by the double beam method using a device in which a folder with a polarizing element was set in a spectrophotometer (UV-3150 manufactured by Shimadzu Corporation). The folder was provided with a mesh that cuts the amount of light by 50% on the reference side. The 380 nm transmittance of the transparent protective film was 8%.

(6) Evaluation of optical laminate (i) Evaluation of flexibility For evaluation of flexibility, the general coating test method described in JIS-K-5600-5-1-flexibility (cylindrical mandrel method) method is used. Using, it was done as follows.
The optical laminate is cut into 25 mm × 200 mm squares, and the diameter is increased under the conditions of a temperature of 25 ° C and a relative humidity of 55% RH using a cylindrical mandrel method bending resistance tester type II (manufactured by TP Giken Co., Ltd.). A bending test was performed by winding a mandrel rod having a bending radius of 6 mm (bending radius R = 3 mm) with the liquid crystal cured layer of the retardation film on the outside. Using the optical laminate after the test, the cracks were visually confirmed by illuminated transmitted light in a dark room environment, and when the cracks were observed, the cracks were marked as "x" and the cracks could not be seen. The thing was judged as "○". The results are shown in Table 1.

(Ii) Evaluation of oblique reflectance The oblique reflectance of the optical laminate was measured as follows. A measurement sample was prepared by laminating the side derived from the retardation film of the optical laminate (in the case of the optical laminate I, the liquid crystal cured film) and the reflector (mirror surface aluminum plate) using an acrylic pressure-sensitive adhesive.
Using a spectrocolorimeter (CM3700A manufactured by Konica Minolta Co., Ltd.), the light of the D65 light source was incident on the measurement sample from the 8 ° direction, and the oblique reflectance (reflection Y value) was measured. When the oblique reflectance was 1% or more and less than 6%, it was evaluated as ◯, when it was 6% or more and less than 8%, it was evaluated as Δ, and when it was 8% or more, it was evaluated as ×. The results are shown in Table 1.

(Iii) Evaluation of heat resistance test A measurement sample was prepared by laminating the side derived from the retardation film of the optical laminate and the glass plate using an acrylic adhesive.
After 500 hours have passed since the obtained measurement sample was placed in an oven at 85 ° C., the in-plane retardation value was measured and the amount of change in the in-plane retardation value at 550 nm before and after the heat resistance test was measured by Oji Measuring Instruments Co., Ltd. It was measured using KOBRA-WR of. When the amount of change was 1 nm or more and less than 3 nm, it was evaluated as ◯, when it was 3 nm or more and less than 5 nm, it was evaluated as Δ, and when it was 5 nm or more, it was evaluated as ×. The results are shown in Table 1.

[Example 2]
When the retardation film and the splitter are bonded, the same as in Example 1 except that the liquid crystal cured film side is bonded to the polarizing element, the base film / optical alignment film / liquid crystal cured film / adhesive layer / An optical laminate composed of a splitter / adhesive layer / transparent protective film was manufactured and evaluated. The results are shown in Table 1.

[Example 3]
Implemented except that a polymethyl methacrylate resin film (manufactured by Sumitomo Chemical Co., Ltd., moisture permeability: 50 g / m ^2/24 hours, total light transmission rate: 93%, 380 nm transmission rate: 6%) was used as the transparent protective film. In the same manner as in Example 1, an optical laminate composed of a base film / photoalignment film / liquid crystal curing film / adhesive layer / polarizing element / adhesive layer / transparent protective film was produced and evaluated.
The results are shown in Table 1.

[Example 4]
Cycloolefin polymer film (COP; ZF-14; manufactured by Nippon Zeon Co., Ltd., moisture permeability: 13 g / m ^2/24 hours, total light transmittance: 92%, 380 nm transmittance:) to which an ultraviolet absorber is added as a transparent protective film. An optical laminate composed of a base film / a photoalignment film / a liquid crystal curing film / an adhesive layer / a polarizing element / an adhesive layer / a transparent protective film was produced in the same manner as in Example 1 except that 8%) was used. And evaluated. The results are shown in Table 1.

[Comparative Example 1]
As the base film, the TAC film used as the transparent protective film of Example 1 was used, and in the process of producing the optical laminate, the transparent protective film and the polarizing element were dried in the same water-based manner as in Example 1. After bonding with a solidifying adhesive, use an acrylic pressure-sensitive adhesive with a thickness of 5 μm after curing to cover the surface on the side where the transparent protective film of the stator is not laminated and the liquid crystal cured film side of the retardation film. From the photoalignment film / liquid crystal curing film / pressure-sensitive adhesive layer / polarizing element / adhesive layer / transparent protective film in the same manner as in Example 1 except that the triacetyl cellulose film which is the base film was peeled off by bonding. The optical laminate was manufactured and evaluated. The results are shown in Table 1.

[Comparative Example 2]
Substrate film / optical alignment film / liquid crystal curing film / pressure-sensitive adhesive layer / polarizing element / adhesive layer / transparent protective film in the same manner as in Comparative Example 1 except that the base film triacetyl cellulose was not peeled off. An optical laminate made of the above was manufactured and evaluated. The results are shown in Table 1.

[Reference Example 1]
A cycloolefin polymer film (COP; ZF-14; manufactured by Nippon Zeon Co., Ltd., moisture permeability: 13 g / m ^2/24 hours, total light transmittance: 92%, 380 nm transmittance: 90%) was used as the base film. An optical laminate composed of a base film / a photoalignment film / a liquid crystal curing film / an adhesive layer / a polarizing element / an adhesive layer / a transparent protective film was produced and evaluated in the same manner as in Example 4 except for the above. .. The results are shown in Table 1.

It was confirmed that the optical laminates (Examples 1 to 4) having a layer structure according to the present invention were excellent in flexibility and low oblique reflectance.

1: Phase difference film 2: Adhesive layer 3: Polarizer 4: Adhesive layer 5: Transparent protective film 11: Base film 12: Alignment film 13: Liquid crystal cured film 100: Optical laminate

Claims

An optical laminate containing a retardation film, a splitter, and a transparent protective film in this order.
The retardation film has a base film having a moisture permeability of 100 g / m 2/24 hours or more, and a thickness of 0.5 μm or more and 3 μm or less formed on the base film, and the following formula ( 1) and (2):
Re (450) / Re (550) ≤ 1.00 (1)
1.00 ≤ Re (650) / Re (550) (2)
[In the equation, Re (λ) indicates the in-plane phase difference value at the wavelength λ]
Contains a liquid crystal cured film, which fills with a single layer,
The polarizing element is composed of a polyvinyl alcohol-based resin film containing a dichroic dye, and the transparent protective film has a total light transmittance of 90% or more and a 380 nm transmittance of 30% or less.
An optical laminate in which the retardation film, the polarizing element, and the transparent protective film are adjacent to each other via an adhesive layer.
The optical laminate according to claim 1, wherein the base film has a total light transmittance of 90% or more and an absolute value of the retardation value Rth (550) in the thickness direction with respect to light of 550 nm is 5 nm or less. body.
The optical laminate according to claim 1 or 2, wherein the retardation film has a photoalignment film having a thickness of 10 nm or more and 1000 nm or less between a base film and a liquid crystal cured film.
The optical laminate according to any one of claims 1 to 3, wherein the liquid crystal cured film is a film obtained by curing at least one compound having at least one maximum absorption between wavelengths of 300 to 400 nm.
The liquid crystal cured film has the following formula (3):
100 nm ≤ Re (550) ≤ 170 nm (3)
[In the equation, Re (λ) indicates the in-plane phase difference value at the wavelength λ]
The optical laminate according to any one of claims 1 to 4, which satisfies the above conditions.
The optical laminate according to any one of claims 1 to 5, wherein the transparent protective film has a moisture permeability of 100 g / m 2/24 hours or more.
The optical laminate according to any one of claims 1 to 6, wherein the adhesive layer is a layer formed from a dry solidified adhesive.
The optical laminate according to claim 7, wherein the dry solidified adhesive contains polyvinyl alcohol.
The optical laminate according to any one of claims 1 to 8, wherein the retardation film is in contact with an adhesive layer for bonding the retardation film and a polarizing element on the liquid crystal curing film side.
An optical laminate roll formed by winding the optical laminate according to any one of claims 1 to 9.
An elliptical polarizing plate including the optical laminate according to any one of claims 1 to 9.
An organic EL display device including the elliptical polarizing plate according to claim 11.
A flexible image display device including the elliptical polarizing plate according to claim 11.
The flexible image display device according to claim 13, further including a window and a touch sensor.