KR20230062548A - Optical laminate and elliptically polarizing plate including the same - Google Patents

Abstract

An object of the present invention is to provide an optical laminate that does not undergo deformation when bent and is excellent in high flexibility and oblique reflectance, particularly suitable for flexible displays. An optical laminate comprising a retardation film, a polarizer, and a transparent protective film in this order, wherein the retardation film comprises a base film having a water vapor transmission rate of 100 g/m 2 /24 hours or more, and a thickness of 0.5 μm formed on the base film. 3 μm or less, and the following formulas (1) and (2):
Re(450)/Re(550) ≤ 1.00 (1)
1.00 ≤ Re(650)/Re(550) (2)
[Wherein, Re(λ) represents an in-plane retardation value at a wavelength λ] of a single-layer liquid crystal cured film, wherein the polarizer is a polyvinyl alcohol-based resin film containing a dichroic dye. constituted, wherein the transparent protective film has a total light transmittance of 90% or more and a 380 nm transmittance of 30% or less, and the retardation film, the polarizer, and the transparent protective film are adjacent to each other via an adhesive layer. An optical laminate.

Description

Optical laminate and elliptically polarizing plate including the same

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

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

Japanese Unexamined Patent Publication No. 2011-207765

In recent years, there has been a demand for flexible display, and an elliptically polarizing plate having high flexibility while being thinned is required. A retardation film obtained by curing a polymerizable liquid crystal compound as described in Cited Document 1 is suitable for a flexible display from the viewpoint of realizing thinness. An elliptically polarizing plate (film) can be produced by transferring through an intervening layer.

However, when the present inventors transfer a retardation plate formed of a liquid crystal cured film using a pressure-sensitive adhesive, when the elliptically polarizing plate thus formed is bent, deformation easily occurs at the inflection point, resulting in stripe-like defects or inclinations. It has been found that an increase in light reflectance from a direction (oblique reflectance) can occur.

An object of the present invention is to provide an optical laminate that does not easily cause deformation when bent and is excellent in high bendability and oblique reflectance, particularly suitable for flexible displays.

The present inventors came to complete this invention as a result of earnest examination in order to solve the said subject. That is, the present invention includes the following aspects.

[1] An optical laminate comprising a retardation film, a polarizer and a transparent protective film in this order,

The retardation film has a base film having a moisture permeability of 100 g/m/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 formulas (1) and (2):

Re(450)/Re(550) ≤ 1.00 (One)

1.00 ≤ Re(650)/Re(550) (2)

[Wherein, Re(λ) represents the in-plane retardation value at the wavelength λ]

It is made of a liquid crystal cured film that satisfies as a single layer,

The polarizer is composed of a polyvinyl alcohol-based resin film containing a dichromatic 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 comprising the retardation film, the polarizer, and the transparent protective film adjoining each other via an adhesive layer.

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

[3] The optical laminate according to [1] or [2], wherein the retardation film has a photo-alignment film having a thickness of 10 nm or more and 1000 nm or less between the base film and the liquid crystal cured film.

[4] The optical laminate according to any one of [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 and 400 nm.

[5] The liquid crystal cured film is the following formula (3):

100 nm ≤ Re(550) ≤ 170 nm (3)

[Wherein, Re(λ) represents the in-plane retardation value at the wavelength λ]

The optical laminate according to any one of [1] to [4] above, which satisfies.

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

[7] The optical laminate according to any one of [1] to [6], wherein the adhesive layer is a layer formed of a dry and solidified adhesive.

[8] The optical laminate according to the above [7], wherein the dry and solidified 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 the polarizer together from the side of the liquid crystal cured film.

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

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

[12] An organic EL display device comprising the elliptically polarizing plate according to [11] above.

[13] A flexible image display device including the elliptically polarizing plate according to [11] above.

[14] The flexible image display device according to [13], further including a window and a touch sensor.

ADVANTAGE OF THE INVENTION According to this invention, when it bends, deformation does not generate|occur|produce easily and an optical laminate excellent in high bendability and oblique reflectance, especially an optical laminate suitable for a flexible display can be provided.

1 is a schematic cross-sectional view showing an example of the layer configuration of an optical laminate of the present invention.
Fig. 2 is a schematic sectional view showing an example of the layer structure of the optical laminate of the present invention.

EMBODIMENT OF THE INVENTION Hereinafter, embodiment of this invention is described in detail. In addition, the scope of the present invention is not limited to the embodiment described here, and various changes can be made within a range not impairing the gist of the present invention.

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

(adhesive layer)

In the optical laminate of the present invention, the retardation film and the polarizer, and the polarizer and the transparent protective film are laminated via an adhesive layer, respectively. When the optical laminate obtained by bonding the retardation film and the polarizer, and the polarizer and the transparent protective film together with an adhesive layer is repeatedly bent, the deformation in the liquid crystal cured film constituting the retardation film and the optical laminate as a whole It is considered that the deformations easily follow each other, and the deformation with respect to the inflection point is less likely to occur, and the stripe-like defects and the increase in the oblique reflectance caused by the deformation can be suppressed.

The adhesive layer which adheres retardation film and a polarizer, and a polarizer and a transparent protective film can be formed with an adhesive agent. Examples of the adhesive capable of forming such an adhesive layer include dry solidified adhesives such as water-based adhesives and chemically reactive adhesives such as active energy ray curable adhesives. Although the adhesive layer which adheres retardation film and a polarizer, and a polarizer and a transparent protective film may be formed with mutually different adhesive agents, it is preferable to form with the same adhesive agent.

As the dry solidified 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 a polyhydric aldehyde, an epoxy compound, an epoxy resin, and compositions containing crosslinking agents or curable compounds such as melamine compounds, zirconia compounds, and zinc compounds. Examples of polymers of monomers 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 copolymers, itaconic acid copolymers, acrylic acid copolymers, acrylamide copolymers, saponified products of polyvinyl acetate, and A polyvinyl alcohol-type resin etc. are mentioned.

As the polyvinyl alcohol-based resin, 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 etc. are mentioned. The content of the polyvinyl alcohol-based resin in the water-based dry solidification 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.

As a urethane resin, a polyester-type ionomer type urethane resin etc. are mentioned.

The polyester ionomer type urethane resin referred to herein is a urethane resin having a polyester skeleton, into which a small amount of ionic component (hydrophilic component) is introduced. Since the related ionomer type urethane resin emulsifies in water to form an emulsion without using an emulsifier, it can be used as a water-based dry solidification type adhesive. When using a polyester ionomer type urethane resin, it is effective to mix|blend a water-soluble epoxy compound as a crosslinking agent.

As the epoxy resin, polyamide epoxy obtained by reacting epichlorohydrin with polyamide polyamine obtained by reaction of polyalkylene polyamine such as diethylenetriamine or triethylenetetramine with dicarboxylic acid such as adipic acid Resin etc. are mentioned. Examples of commercially available products of such polyamide epoxy resin include "Sumirez Resin (registered trademark) 650" and "Sumirez Resin (registered trademark) 675" (above, manufactured by Sumika Chemtex Co., Ltd.), and "WS-525" (Nippon PMC Corporation). production), etc. When blending the epoxy resin, the amount added is usually 1 to 100 parts by mass, preferably 1 to 50 parts by mass, based on 100 parts by mass of the polyvinyl alcohol-based resin.

Especially, it is preferable that the dry solidification adhesive is a water-system dry solidification adhesive containing a polyvinyl alcohol-type resin.

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

An active energy ray curing type adhesive, which is a chemically reactive adhesive, is an adhesive that is cured by receiving irradiation with an active energy ray. The active energy ray curable adhesive may contain a solvent.

As the active energy ray curing type adhesive, 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, a cationically polymerizable curing component such as an epoxy compound, and Adhesives containing both radically polymerizable curing components such as acrylic compounds and further containing cationic polymerization initiators and radical polymerization initiators, and adhesives cured by irradiation of electron beams without containing these polymerization initiators, and the like are exemplified. .

Among them, active energy ray curable adhesives include radically polymerizable active energy ray curable adhesives containing an acrylic curing component and a radical polymerization initiator, and cationically polymerizable active energy ray curable adhesives containing an epoxy compound and a cationic polymerization initiator. desirable. 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 compounds other than an epoxy compound. Examples of compounds other than epoxy compounds include oxetane compounds and acrylic compounds.

Examples of the radical polymerization initiator include a photopolymerization initiator described later as one that can be incorporated into a polymerizable liquid crystal composition forming a liquid crystal cured film. Commercially available products of the cationic polymerization initiator include "Kayarad" (registered trademark) series (manufactured by Nippon Kayaku Co., Ltd.), "Cyracure UVI" series (manufactured by Dow Chemical Co., Ltd.), "CPI" series (manufactured by San-Apro Co., Ltd.), “TAZ”, “BBI” and “DTS” (above, manufactured by Midori Chemical Co., Ltd.), “Adeka Optoma” series (manufactured by ADEKA Corporation), “RHODORSIL” (registered trademark) (manufactured by Rhodia Corporation), and the like. The content of the radical polymerization initiator and cationic polymerization initiator is usually 0.5 to 20 parts by mass, preferably 1 to 15 parts by mass, based on 100 parts by mass of the active energy ray curable adhesive.

In an optical laminate formed by laminating a retardation film, a polarizer, and a transparent protective film in this order, compared with a pressure-sensitive adhesive formed of a high-viscosity material from the viewpoint of thinning the laminate and improving flexibility, the dry solidified adhesive It is considered advantageous to use an adhesive such as a chemically reactive adhesive. On the other hand, the optical layered body of the present invention includes a liquid crystal cured film that exhibits the optical properties represented by formulas (1) and (2) in a single layer, and the polymerizable liquid crystal compound forming such a liquid crystal cured film is as described later. , generally has a maximum absorption wavelength between the wavelengths of 300 and 400 nm in many cases. In addition, since the transparent protective film located on the viewing side when incorporated in the image display device has an ultraviolet ray absorbing ability in order to protect the internal structure of the optical layered body from ultraviolet rays, in the manufacture of an optical layered body having such a configuration, The irradiated ultraviolet rays are absorbed by the liquid crystal curing film or the transparent protective film, and there are cases where it is difficult for the ultraviolet rays in an amount sufficient to cure the adhesive to reach the inside of the laminate. Therefore, in the optical laminate of the present invention, which can be configured to be sandwiched between layers having ultraviolet absorbing ability (liquid crystal cured film and transparent protective film), an adhesive for bonding the retardation film and the polarizer, and the polarizer and the transparent protective film In addition to the viewpoint of thinning and improving flexibility, using a dry solidification type adhesive agent as an adhesive is advantageous from a viewpoint of obtaining an optical laminate with more excellent adhesion between each layer.

The thickness of the adhesive layer for bonding the retardation film and the polarizer and the polarizer and the transparent protective film together is preferably 10 nm or more, more preferably 30 nm or more, still more preferably 50 nm or more, and preferably 5 μm or less, more preferably 3 μm or less, still more preferably 2 μm or less. When the thickness of the adhesive layer is within the above range, deformation at the inflection point is less likely to occur when repeatedly bent, and generation of stripe-like defects and increase in oblique reflectance due to this are less likely to be suppressed. The thickness of the adhesive layer bonding the retardation film and the polarizer and the polarizer and the transparent protective film together may be the same or different from each other.

The thickness of the adhesive layer can be measured using, for example, an interference film thickness meter, a laser microscope, or a stylus film thickness meter.

(Phase difference film)

The retardation film constituting the optical layered body 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 water vapor transmission rate of the base film is preferably 150 g/m 2 /24 hours or more, more preferably 200 g/m 2 /24 hours or more. When the moisture permeability of the base film constituting the retardation film is equal to or greater than the lower limit, the moisture content in the optical laminate formed by laminating the retardation film with the polarizer is easily controlled, and in particular, as an adhesive forming the adhesive layer, the dry solidified adhesive is used. In the case of using, it is easy to remove the solvent in the adhesive, and it is easy to prepare an adhesive layer having physical properties close to the elasticity or flexibility of the liquid crystal cured film formed on the base film. For this reason, when the optical laminate is bent, the adhesive layer bonding each layer does not easily affect the deformation in the liquid crystal cured film, and the deformation of the entire optical laminate and the deformation in each layer easily follow each other. lose Thereby, even when it is repeatedly bent, deformation at the inflection point is less likely to occur, and stripe-like defects and an increase in oblique reflectance resulting from this are suppressed. The upper limit of the water vapor transmission rate 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.

In addition, the water vapor transmission rate of a base film can be measured by JIS Z 0208 (cup method), for example. Specifically, it can be measured according to the method described in the Examples described later.

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

Examples of the resin constituting the base film having a water vapor transmission rate of 100 g/m 2 /24 hours or more include triacetyl cellulose, polyvinylpyrrolidone-based polymers, and (meth)acrylamide-based polymers. From viewpoints of ease and the like, triacetyl cellulose is preferred. Such a resin can be formed into a film by a known means such as a solvent casting method or a melt extrusion method to make a base film. Moreover, you may use a commercial item.

The thickness of the base film can be appropriately determined according to the configuration of the desired optical layered body, but from the viewpoints of thinning of the optical layered body, workability, flexibility and strength, etc., it is usually 5 μm to 300 μm, preferably 15 μm to 200 μm. μm, 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 equal to or greater than the lower limit, an optical laminate having high transparency and excellent optical properties can be formed. The upper limit of the total light transmittance in the base film is not particularly limited, and may be 100% or less. The total light transmittance can be measured according to JIS K 7361, for example.

In the base film, the absolute value of the retardation value Rth (550) in the thickness direction for light of 550 nm is preferably 5 nm or less, and more preferably 3 nm or less. By controlling the retardation value in the thickness direction of the base film, it is difficult to influence the optical properties expected by the liquid crystal cured film, and the oblique reflectance of the obtained optical laminate can be suppressed low. Since such an optical laminate is excellent in suppression of light leakage and color change during black display when incorporated in a display device or the like, it becomes an optical laminate advantageous in optical characteristics. The retardation value Rth (550) of the base film is preferably as small as possible, and may be 0 nm. The retardation value Rth (550) of the base film can be controlled not only by the blending of the additives, but also by the casting method and the like.

The surface of the base film is subjected to surface treatment such as corona treatment or plasma treatment in order to improve adhesion to these components, etc. it may be

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 (One)

1.00 ≤ Re(650)/Re(550) (2)

[Wherein, Re(λ) represents the in-plane retardation value at the wavelength λ]

It is a liquid crystal cured film that satisfies as a single layer. "Satisfied with a single layer" means that a cured film of one layer obtained from a polymerizable liquid crystal compound containing a liquid crystal compound is a single layer, and exhibits optical properties represented by the above formulas (1) and (2).

When the liquid crystal cured film satisfies the formulas (1) and (2), the liquid crystal cured film exhibits so-called reverse 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. In the case of exhibiting reverse wavelength dispersion, there is a tendency to exhibit constant retardation performance in a wide wavelength range of visible light, and the optical properties of the optical laminate are likely to be improved. By using a liquid crystal cured film (hereinafter also referred to as "liquid crystal cured film (x)") having optical properties satisfying the above formulas (1) and (2) as a single layer, a thinner retardation film with excellent optical properties can be obtained. You can get it.

Re (450) / Re (550) is preferably 0.70 or more, more preferably 0.78 or more, since the reverse wavelength dispersion is improved and the effect of improving the reflection color in the front direction of the liquid crystal cured film can be further enhanced. , Again, it is preferably 0.95 or less, more preferably 0.92 or less. Further, Re(650)/Re(550) is preferably 1.0 or more, more preferably 1.01 or more, still more preferably 1.02 or more.

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

In addition, the liquid crystal cured film (x) is the following formula (3):

100 nm ≤ Re(550) ≤ 170 nm (3)

[Wherein, Re(λ) represents the in-plane retardation value at the wavelength λ]

It is desirable to satisfy When the liquid crystal cured film (x) satisfies Formula (3), frontal reflection color during black display when an optical laminate (elliptically polarizing plate) containing the liquid crystal cured film (x) is applied to an organic EL display device is improved. it becomes easier to become 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 can be used in the field of retardation films.

A polymerizable liquid crystal compound is a liquid crystal compound having a polymerizable group. As the polymerizable liquid crystal compound, generally, a polymer (cured product) obtained by polymerizing the polymerizable liquid crystal compound alone in a state oriented in a specific direction is a polymerizable liquid crystal compound exhibiting positive wavelength dispersion and reverse wavelength dispersion A polymerizable liquid crystal compound showing a is exemplified. From the standpoint of easily obtaining a liquid crystal cured film that satisfies the optical properties represented by the above formulas (1) and (2) alone, the liquid crystal cured film (x) constituting the retardation film in the present invention is oriented in a specific direction alone It is preferable that the polymer (cured product) obtained by polymerization in one state is a cured product of a polymerizable liquid crystal composition containing a polymerizable liquid crystal compound exhibiting reverse wavelength dispersion.

A polymerizable group refers to a group capable of participating in a polymerization reaction. In the present invention, the polymerizable group of the polymerizable liquid crystal compound forming the cured liquid crystal film is preferably a photopolymerizable group. A photopolymerizable group is a polymerizable group and refers to a group that can be involved in a polymerization reaction by a reactive active species generated from a 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 oxiranyl group, and an oxetanyl group. can be heard Especially, an acryloyloxy group, a methacryloyloxy group, a vinyloxy group, an oxiranyl group, and an oxetanyl group are preferable, and an acryloyloxy group is more preferable.

The liquid crystal exhibited by the polymerizable liquid crystal compound may be either a thermotropic liquid crystal or a lyotropic liquid crystal, but a thermotropic liquid crystal is preferable in terms of precise film thickness control. Moreover, as a phase-ordered structure in a thermotropic liquid crystal, a nematic liquid crystal, a smectic liquid crystal, or a discotic liquid crystal may be sufficient as it. A polymerizable liquid crystal compound can be used individually or in combination of 2 or more types.

A polymerizable liquid crystal compound having a so-called T-shaped or H-shaped molecular structure tends to exhibit reverse wavelength dispersion, and a polymerizable liquid crystal compound having a T-shaped molecular structure tends to exhibit stronger reverse wavelength dispersion.

The polymerizable liquid crystal compound exhibiting reverse wavelength dispersion 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) It has π electrons on the major axis direction (a) of the polymerizable liquid crystal compound.

(C) It has π electrons in a direction crossing the major axis direction (a) [crossing direction (b)].

(D) The long axis of a polymerizable liquid crystal compound defined by the following formula (i) where N(πa) is the sum of π electrons present in the long axis direction (a) and N(Aa) is the sum of molecular weights present in the long axis direction π electron density in direction (a):

D(πa) = N(πa)/N(Aa) (i)

And, the sum of π electrons present in the cross direction (b) is N (π b), and the sum of molecular weights present in the cross direction (b) is N (Ab), and the polymerizable liquid crystal compound defined by the following formula (ii) π electron density in the cross direction (b) of:

D(πb) = N(πb)/N(Ab) (ii)

A, formula (iii)

0 ≤ [D(πa)/D(πb)] < 1 (iii)

[That is, the π electron density in the cross direction (b) is greater than the π electron density in the major axis direction (a)]. As described above, a polymerizable liquid crystal compound having π electrons on a long axis and a cross direction with respect thereto generally tends to have a T-shaped structure.

In the above characteristics (A) to (D), the major axis direction (a) and the number of π electrons N are defined as follows.

· The major axis direction (a) is, for example, in the case of a compound having a rod-like structure, it is the rod-shaped major axis direction.

• The number of π electrons N(πa) present in the major axis direction (a) does not include π electrons lost due to polymerization.

The number of π electrons present on the major axis direction (a), N(πa), is the total number of π electrons on the major axis and π electrons conjugated thereto, for example, as a ring existing on the major axis direction (a) , the number of π electrons present in the ring satisfying the Hickel's law.

• The number of π electrons N(πb) present in the cross direction (b) does not include π electrons lost due to the polymerization reaction.

A polymerizable liquid crystal compound satisfying the above has a mesogenic structure in the long axis direction. A liquid crystal phase (nematic phase, smectic phase) is expressed by this mesogenic 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) above the phase transition temperature. In the nematic phase or smectic phase formed by aligning the polymerizable liquid crystal compound, the major axis directions of the polymerizable liquid crystal compound are usually aligned so that they are parallel to each other, and the major axis direction becomes the orientation direction of the nematic phase or smectic phase. When such a polymerizable liquid crystal compound is made into a film and polymerized in a nematic or smectic state, a polymer film composed of a polymer oriented in the major axis direction (a) can be formed. This polymer film absorbs ultraviolet rays by π electrons in the long axis direction (a) and π electrons in the cross direction (b). Here, the maximum absorption wavelength of ultraviolet rays absorbed by π electrons in the crossing direction (b) is λbmax. λbmax is usually 300 nm to 400 nm. The density of π electrons satisfies the above formula (iii), and since the π electron density in the cross direction (b) is greater than the π electron density in the major axis direction (a), linearly polarized light having an oscillation plane in the cross direction (b) The polymer film has higher absorption of ultraviolet rays (wavelength: λbmax) than absorption of linearly polarized ultraviolet rays (wavelength: λbmax) having a vibrating surface in the major axis direction (a). The ratio (ratio of absorbance of linearly polarized ultraviolet light in the cross direction (b)/absorbance in the major axis direction (a)) is, for example, more than 1.0, preferably 1.2 or more, and usually 30 or less, for example 10 or less. .

Generally, the polymerizable liquid crystal compound having the above characteristics is often one in which the birefringence of the polymer exhibits reverse wavelength dispersion when polymerized in a state 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)") is exemplified.

[Formula 1]

In Formula (X), Ar represents a divalent group having an aromatic group which may have a substituent. Examples of the aromatic group referred to herein include groups exemplified by (Ar-1) to (Ar-23) described later. Moreover, Ar may have 2 or more aromatic groups. The aromatic group may contain at least one of a nitrogen atom, an oxygen atom, and a sulfur atom. When two or more aromatic groups are included in Ar, the two or more aromatic groups may be bonded to each other via a single bond or a divalent bonding group such as -CO-O- or -O-.

G ¹ and G ² each independently represent a divalent aromatic group or a divalent alicyclic hydrocarbon group. Here, the hydrogen atom contained in the divalent aromatic group or the divalent alicyclic hydrocarbon group is a halogen atom, an alkyl group of 1 to 4 carbon atoms, a fluoroalkyl group of 1 to 4 carbon atoms, an alkoxy group of 1 to 4 carbon atoms, a cyano group, or It may be substituted with a nitro group, and the carbon atom constituting the divalent aromatic group or the divalent alicyclic hydrocarbon group may be substituted with an oxygen atom, a sulfur atom or a nitrogen atom.

L ¹ , L ² , B ¹ and B ² are each independently a single bond or a divalent linking group.

Each of k and l independently represents an integer of 0 to 3, and satisfies the relationship of 1 ≤ k + l. Here, in the case of 2 ≤ k+l, B ¹ and B ² , G ¹ and G ² may be the same as or different from each other.

Each of E ¹ and E ² independently represents an alkanediyl group having 1 to 17 carbon atoms, and an alkanediyl group having 4 to 12 carbon atoms is more preferable. In addition, the hydrogen atom contained in the alkanediyl group may be substituted with a halogen atom, and -CH ₂ - contained in the alkanediyl group may be substituted with -O-, -S-, or -C(=O)-. do.

P ¹ and P ² each 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, preferably a 1,4-phenylenediyl group optionally substituted with at least one substituent selected from the group consisting of a halogen atom and an alkyl group having 1 to 4 carbon atoms, a halogen atom, and a carbon number A 1,4-cyclohexanediyl group which may be substituted with at least one substituent selected from the group consisting of 1 to 4 alkyl groups, more preferably a 1,4-phenylenediyl group substituted with a methyl group, an unsubstituted 1 , 4-phenylenediyl group or unsubstituted 1,4-trans-cyclohexanediyl group, particularly preferably unsubstituted 1,4-phenylenediyl group or unsubstituted 1,4-trans-cyclohexane It is a diary.

In addition, it is preferable that at least one of the plurality of G ¹ and G ² is a divalent alicyclic hydrocarbon group, and at least one of G ¹ and G ² bonded to L ¹ or L ² is a divalent alicyclic hydrocarbon It is more preferable to originate.

L ¹ and L ² are each independently, preferably, a single bond, an alkylene group having 1 to 4 carbon atoms, -O-, -S-, -R ^a1 OR ^a2 -, -R ^a3 COOR ^a4 -, -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 of 1 to 4 carbon atoms, and R ^c and R ^d represent an alkyl group of 1 to 4 carbon atoms or a hydrogen atom. L ¹ and L ² are each independently, more preferably a single bond, -OR ^a2-1 -, -CH ₂ -, -CH ₂ CH ₂ -, -COOR ^a4-1 -, or -OCOR ^a6-1 - am. Here, R ^a2-1 , R ^a4-1 , and R ^a6-1 each independently represent a single bond, -CH ₂ -, or -CH ₂ CH ₂ -. L ¹ and L ² are each independently, more preferably a single bond, -O-, -CH ₂ CH ₂ -, -COO-, -COOCH ₂ CH ₂ -, or -OCO-.

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

The range of k and l is preferably 2 ≤ k + l ≤ 6 from the viewpoint of expression of reverse wavelength dispersion, preferably k + l = 4, and more preferably k = 2 and l = 2. If k = 2 and l = 2, it becomes a symmetrical structure, so it is preferable.

Examples of the polymerizable group represented by P ¹ or P ² include an epoxy group, a vinyl group, a vinyloxy group, a 1-chlorovinyl group, an isopropenyl group, a 4-vinylphenyl group, an acryloyloxy group, a methacryloyloxy group, and an oxiranyl group. , And an oxetanyl group, etc. are mentioned.

Especially, an acryloyloxy group, a methacryloyloxy group, a vinyl group, and a vinyloxy group are preferable, and an acryloyloxy group and a methacryloyloxy group are more preferable.

Ar preferably has at least one selected from an aromatic hydrocarbon ring which may have a substituent, an aromatic heterocyclic ring which may have a substituent, and an electron-withdrawing group. As the said aromatic hydrocarbon ring, a benzene ring, a naphthalene ring, an anthracene ring etc. are mentioned, for example, 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, and a pyrroline ring. , imidazole ring, pyrazole ring, thiazole ring, benzothiazole ring, thienothiazole ring, oxazole ring, benzoxazole ring, and phenanthroline ring. Especially, what has a thiazole ring, a benzothiazole ring, or a benzofuran ring is preferable, and what has a benzothiazole ring is more preferable. Further, when Ar contains a nitrogen atom, the nitrogen atom preferably has π electrons.

In formula (X), the total number of π electrons _Νπ 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, particularly preferably is 16 or greater. Moreover, it is preferably 32 or less, more preferably 26 or less, still more preferably 24 or less.

As an aromatic group contained in Ar, the following groups are mentioned, for example.

[Formula 2]

In formulas (Ar-1) to (Ar-23), * indicates a linking portion, and Z ⁰ , Z ¹ and Z ² are each independently a hydrogen atom, a halogen atom, an alkyl group having 1 to 12 carbon atoms, or cyano. No group, nitro group, C1-C12 alkylsulfinyl group, C1-C12 alkylsulfonyl group, carboxyl group, C1-C12 fluoroalkyl group, C1-C12 alkoxy group, C1-C12 alkylthio group , N-alkylamino group of 1 to 12 carbon atoms, N,N-dialkylamino group of 2 to 12 carbon atoms, N-alkylsulfamoyl group of 1 to 12 carbon atoms or N,N-dialkylsulfamoyl group of 2 to 12 carbon atoms indicates Moreover, Z ⁰ , Z ¹ and Z ² may contain a polymerizable group.

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

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

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

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

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

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

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

Q ¹ and Q ² are preferably -NH-, -S-, -NR ^2' -, or -O-, and R ^2' is preferably a hydrogen atom. Especially, -S-, -O-, and -NH- are especially preferable.

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

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

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

As a polymerizable liquid crystal compound capable of forming the liquid crystal cured film (x), specifically, a polymerizable liquid crystal compound described in Japanese Patent Application Laid-Open No. 2011-207765, Japanese Patent Application Laid-Open No. 2010-031223, etc. is exemplified. can In addition, as long as the liquid crystal cured film (x) satisfying the above formulas (1) and (2) can be formed in a single layer, a polymerizable liquid crystal compound whose homopolymer exhibits positive wavelength dispersion may be used in an appropriate amount.

The content of the polymerizable liquid crystal compound in the polymerizable liquid crystal composition for forming the liquid crystal cured film (x) is, for example, 70 to 99.5 parts by mass, preferably 80 to 99.5 parts by mass, based on 100 parts by mass of the solid content of the polymerizable liquid crystal composition. It is 99 parts by mass, more preferably 85 to 98 parts by mass, still more 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 orientation of the obtained liquid crystal cured film (x). In addition, in this specification, solid content of a polymeric liquid crystal composition means all components except volatile components, such as an organic solvent, from a polymerizable liquid crystal composition.

In addition to the polymerizable liquid crystal compound, the polymerizable liquid crystal composition for forming the liquid crystal cured film (x) may further contain additives such as a solvent, a polymerization initiator, a leveling agent, an antioxidant, a photosensitizer, and a reactive additive. . These components may use only 1 type, respectively, and may use them in combination of 2 or more types.

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. As the solvent, a solvent capable of dissolving the polymerizable liquid crystal compound but inactive to the polymerization reaction of the polymerizable liquid crystal compound is preferable. Moreover, it is preferable that it is a solvent which does not dissolve the base film to be used. As the solvent, for example, 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 alcohol solvents such as glycol monomethyl ether; ester solvents such as ethyl acetate, butyl acetate, ethylene glycol methyl ether acetate, γ-butyrolactone, propylene glycol methyl ether acetate, and ethyl lactate; Ketone solvents, such as acetone, methyl ethyl ketone, cyclopentanone, cyclohexanone, 2-heptanone, and methyl isobutyl ketone; aliphatic hydrocarbon solvents such as pentane, hexane and heptane; alicyclic hydrocarbon solvents such as ethylcyclohexane; aromatic hydrocarbon solvents such as toluene, xylene and anisole; nitrile solvents such as acetonitrile; ether solvents such as tetrahydrofuran and dimethoxyethane; chlorine-containing solvents such as chloroform and chlorobenzene; amide solvents such as dimethylacetamide, dimethylformamide, N-methyl-2-pyrrolidone (NMP), and 1,3-dimethyl-2-imidazolidinone; and the like. These solvents can be used alone or in combination of two or more. Among them, from the viewpoint of film coating, it is preferable to use at least one selected from alcohol solvents, ester solvents, ketone solvents, chlorine-containing solvents, amide solvents and aromatic hydrocarbon solvents, and from the viewpoint of solubility of the polymerizable liquid crystal compound In, it is more preferable to use at least one selected from ester solvents, ketone solvents, amide solvents and aromatic hydrocarbon solvents.

The content of the solvent in the polymerizable liquid crystal composition is preferably 50 to 98 parts by weight, more preferably 70 to 95 parts by weight, based on 100 parts by weight 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 lowered, so 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.

A polymerization initiator is a compound capable of initiating a polymerization reaction such as a polymerizable liquid crystal compound by generating a reactive active species by contribution of heat or light. Active species, such as a radical or a cation or an anion, are mentioned as a reactive active species. Among them, a photopolymerization initiator that generates radicals upon light irradiation is preferable from the viewpoint of easy reaction control.

Examples of the photopolymerization initiator include benzoin compounds, benzophenone compounds, benzylketal compounds, oxime compounds, α-hydroxyketone compounds, α-amino ketone compounds, triazine compounds, iodonium salts and sulfonium salts. may be used, and a commercially available product may be used. Specifically, Irgacure (registered trademark) 907, Irgacure 184, Irgacure 651, Irgacure 819, Irgacure 250, Irgacure 369, Irgacure 379, Irgacure 127, Irgacure 2959, Irgacure 754, Irgacure 379EG (above, manufactured by BASF Japan Co., Ltd.), Shakeol BZ, Shakeol Z, Shakeol BEE (above, manufactured by Seiko Chemical Co., Ltd.), Kayacure BP100 ( Nippon Explosive Co., Ltd.), Kayacure UVI-6992 (manufactured by Dawoo), Adeca Optoma SP-152, Adeka Optoma SP-170, Adeka Optoma N-1717, Adeka Optoma N-1919, Adeka Accruz NCI- 831, Adeka Aqua Cruise NCI-930 (above, manufactured by ADEKA Corporation), TAZ-A, TAZ-PP (above, manufactured by Nippon Seibel Hegner Co., Ltd.), and TAZ-104 (above, manufactured by Sanwa Chemical Co., Ltd.).

The photopolymerization initiator contained in the polymerizable liquid crystal composition is at least one type, may be used in combination of multiple types, and may be appropriately selected in relation to the polymerizable liquid crystal compound contained in the polymerizable liquid crystal composition.

Since the photopolymerization initiator can fully utilize the energy emitted from the light source and has excellent productivity, the maximum absorption wavelength is preferably 300 nm to 400 nm, more preferably 300 nm to 380 nm, and among them, α-aceto Phenone-based polymerization initiators and oxime-based photopolymerization initiators are preferred.

As the α-acetophenone compound, 2-methyl-2-morpholino-1-(4-methylsulfanylphenyl)propan-1-one, 2-dimethylamino-1-(4-morpholinophenyl)- 2-benzylbutan-1-one and 2-dimethylamino-1-(4-morpholinophenyl)-2-(4-methylphenylmethyl)butan-1-one; more preferably 2- Methyl-2-morpholino-1-(4-methylsulfanylphenyl)propan-1-one and 2-dimethylamino-1-(4-morpholinophenyl)-2-benzylbutan-1-one can Examples of commercially available products of the α-acetophenone compound include Irgacure 369, 379EG, and 907 (above, manufactured by BASF Japan Co., Ltd.) and Shakol BEE (manufactured by Seiko Chemical Co., Ltd.).

An oxime ester-type photoinitiator produces radicals, such as a phenyl radical and a methyl radical, when light is irradiated. Although the polymerization of the polymerizable liquid crystal compound preferably proceeds by this radical, an oxime ester-based photopolymerization initiator that generates a methyl radical is particularly preferable in terms of high initiation efficiency of the polymerization reaction. Moreover, it is preferable to use the photoinitiator which can utilize ultraviolet-ray of wavelength 350nm or more efficiently from a viewpoint of advancing a polymerization reaction more efficiently. As the photopolymerization initiator capable of efficiently utilizing ultraviolet rays having a wavelength of 350 nm or more, triazine compounds and carbazole compounds containing an oxime ester structure are preferable, and from the viewpoint of sensitivity, a carbazole compound containing an oxime ester structure is more preferable. . As the carbazole compound containing an oxime ester structure, 1,2-octanedione, 1-[4-(phenylthio)-2-(O-benzoyloxime)], ethanone, 1-[9-ethyl-6 -(2-methylbenzoyl)-9H-carbazol-3-yl]-1-(O-acetyloxime) etc. are mentioned. As commercially available products of the oxime ester photopolymerization initiator, Irgacure OXE-01, Irgacure OXE-02, Irgacure OXE-03 (above, manufactured by BASF Japan Co., Ltd.), Adeka Optoma N-1919, Adeka Acruz NCI-831 (above, 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, more preferably 1 to 15 parts by mass, based on 100 parts by mass of the polymerizable liquid crystal compound. Within the above range, the reaction of the polymerizable group sufficiently proceeds, and it is difficult to disturb the orientation of the polymerizable liquid crystal compound.

The leveling agent is an additive having a function of adjusting the fluidity of the polymerizable liquid crystal composition and further flattening a coating film obtained by applying the composition. For example, silicone-based, polyacrylate-based, and perfluoroalkyl-based leveling agents may be mentioned. Commercially available products may be used as the leveling agent, specifically, DC3PA, SH7PA, DC11PA, SH28PA, SH29PA, SH30PA, ST80PA, ST86PA, SH8400, SH8700, FZ2123 (above, all manufactured by Toray Dow Corning Co., Ltd.), KP321, KP323, KP324, KP326, KP340, KP341, X22-161 A, KF6001 (above, all manufactured by Shin-Etsu Chemical Industry Co., Ltd.), TSF400, TSF401, TSF410, TSF4300, TSF4440, TSF4445, TSF-4446, TSF4452, TSF4460 ( over , all manufactured by Momentive Performance Materials Japan Co., Ltd.), Fluorinert (registered trademark) FC-72, FC-40, FC-43, FC-3283 (the above, all Sumitomo 3M Co., Ltd.) manufacture), Megafac (registered trademark) R-08, R-30, R-90, F-410, F-411, F-443, F-445, F-470, F -477, same F-479, same F-482, same F-483, same F-556 (above, all manufactured by DIC Co., Ltd.), Ftop (trade name) EF301, same EF303, same EF351, same EF352 (above) , all manufactured by Mitsubishi Materials Electron Chemical Co., Ltd.), Suffron (registered trademark) S-381, S-382, S-383, S-393, SC-101, SC-105, KH -40, SA-100 (above, all manufactured by AGC Semi Chemical Co., Ltd.), trade names E1830, E5844 (manufactured by Daikin Fine Chemical Laboratory Co., Ltd.), BM-1000, BM-1100, BYK-352, BYK -353 and BYK-361N (both trade names: manufactured by BM Chemie); and the like. A leveling agent can be used individually or in combination of 2 or more types.

The content of the leveling agent is preferably from 0.01 to 5 parts by mass, more preferably from 0.05 to 3 parts by mass, based on 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, so it is preferable.

By blending the 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, and may be a secondary antioxidant selected from phosphorus-based antioxidants and sulfur-based 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, preferably 0.1 to 5 parts by mass, based on 100 parts by mass of the polymerizable liquid crystal compound. It is a mass part, More preferably, it is 0.1-3 mass parts.

Antioxidant can be used individually or in combination of 2 or more types.

A photoinitiator can be highly sensitized by using a photosensitizer. Examples of the photosensitizer include xanthones such as xanthone and thioxanthone; anthracenes having substituents such as anthracene and alkyl ether; phenothiazine; Rubren can be mentioned. A photosensitizer can be used individually or in combination of 2 or more types. The content of the photosensitizer is usually 0.01 to 10 parts by mass, preferably 0.05 to 5 parts by mass, more preferably 0.1 to 3 parts by mass with respect to 100 parts by mass of the polymerizable liquid crystal compound.

By using a reactive additive, the adhesiveness between a base film and a liquid crystal cured film or between a retardation film and an adhesive layer can be improved. As the reactive additive, it is preferable to have a carbon-carbon unsaturated bond and an active hydrogen reactive group in the molecule. In addition, the "active hydrogen reactive group" as used herein means a group having reactivity to a group having an active hydrogen such as a carboxyl group (-COOH), a hydroxyl group (-OH), an amino group (-NH ₂ ), and a glycidyl group, oxa Representative examples thereof include a sleepy group, a carbodiimide group, an aziridine group, an imide group, an isocyanate group, a thioisocyanate group, and a maleic anhydride group. The number of carbon-carbon unsaturated bonds or active hydrogen reactive groups that the reactive additive has is usually 1 to 20 each, preferably 1 to 10 each.

In the reactive additive, it is preferable that at least two active hydrogen reactive groups exist, and in this case, a plurality of active hydrogen reactive groups may be the same or different.

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

Specific examples of the reactive additive include compounds having a (meth)acrylic group and an epoxy group, such as methacryloxyglycidyl ether and acryloxyglycidyl ether; compounds having a (meth)acrylic group and an oxetane group, such as oxetane acrylate and oxetane methacrylate; compounds having a (meth)acrylic group and a lactone group, such as lactone acrylate and lactone methacrylate; compounds having a vinyl group and an oxazoline group, such as vinyloxazoline and isopropenyloxazoline; oligomers of compounds having a (meth)acryl group and an isocyanate group, such as isocyanatomethyl acrylate, isocyanatomethyl methacrylate, 2-isocyanatoethyl acrylate or 2-isocyanatoethyl methacrylate; can Moreover, the compound etc. which have a vinyl group, a vinylene group, and an acid anhydride, such as methacrylic anhydride, acrylic anhydride, maleic anhydride, or vinyl maleic anhydride, are mentioned. Among them, methacryloxyglycidyl ether, acryloxyglycidyl ether, isocyanatomethyl acrylate, isocyanatomethyl methacrylate, vinyloxazoline, 2-isocyanatoethyl acrylate, 2-isocyanatoethyl Methacrylate or the above oligomer is preferred, and isocyanatomethyl acrylate, 2-isocyanatoethyl acrylate or the above oligomer is particularly preferred.

As the reactive additive, a commercially available product may be used as it is or after being purified as necessary. As a commercial item, Laromer (registered trademark) LR-9000 (made by BASF) is mentioned, for example.

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

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

The liquid crystal cured film (x) is, for example,

A coating film of a polymerizable liquid crystal composition containing at least one kind of polymerizable liquid crystal compound is formed on a base film or an alignment film to be described later, the coating film is dried, and the polymerizable liquid crystal compound in the polymerizable liquid crystal composition is dried. orienting process, and,

Step of forming a liquid crystal cured film by polymerizing a polymerizable liquid crystal compound while maintaining an aligned state

It can be prepared by a method including.

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

As a method for applying the polymerizable liquid crystal composition to a base film or the like, known methods such as spin coating method, extrusion method, gravure coating method, die coating method, bar coating method, application method such as applicator method, and printing method such as flexo method method can be heard.

Then, by removing the solvent by drying or the like, a dry coating film is formed. Examples of the drying method include a natural drying method, an air drying method, a heat drying method, and a vacuum drying method. At this time, while drying and removing the solvent from the coating film by heating the coating film obtained from the polymerizable liquid crystal composition, the polymerizable liquid crystal compound can be oriented in a desired direction with respect to the coating film plane. The heating temperature of the coating film can be appropriately determined in consideration of the polymerizable liquid crystal compound to be used and materials such as a base film forming the coating film, but in order to phase-transform the polymerizable liquid crystal compound into a liquid crystal phase state, usually the liquid crystal phase transition temperature It is necessary that the temperature is higher than that. In order to bring the polymerizable liquid crystal compound into a desired alignment state while removing the solvent contained in the polymerizable liquid crystal composition, for example, the liquid crystal phase transition temperature (smectic phase transition temperature) of the polymerizable liquid crystal compound contained in the polymerizable liquid crystal composition Alternatively, it may be heated to a temperature equal to or higher than the nematic phase transition temperature). The heating temperature is preferably a temperature higher than the liquid crystal phase transition temperature of the polymerizable liquid crystal compound by 3°C or higher, more preferably by 5°C or higher. The upper limit of the heating temperature is not particularly limited, but is preferably 180°C or less, more preferably 150°C or less, in order to avoid damage to the coating film or base film or the like due to heating.

In addition, 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 thermogravimetric differential thermal analysis apparatus (TG-DTA), or the like. In addition, when two or more types of polymerizable liquid crystal compounds are used in combination, the phase transition temperature is obtained by mixing all the polymerizable liquid crystal compounds constituting the polymerizable liquid crystal composition in the same ratio as the composition in the polymerizable liquid crystal composition. It means the temperature measured in the same way as in the case of using a mixture of polymerizable liquid crystal compounds and one type of polymerizable liquid crystal compound. In addition, 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 alone.

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, but is usually 0.5 to 10 minutes, preferably 0.5 to 5 minutes.

Removal of the solvent from the coating film may be performed simultaneously with heating to the liquid crystal phase transition temperature or higher of the polymerizable liquid crystal compound, or may be performed separately, but it is preferable to carry out simultaneously from the viewpoint of productivity improvement. Before heating the polymerizable liquid crystal compound to the liquid crystal phase transition temperature or higher, a preliminary drying step for appropriately removing the solvent in the coating film under conditions in which the polymerizable liquid crystal compound contained in the coating film obtained from the polymerizable liquid crystal composition does not polymerize is performed. can form Examples of the drying method in this pre-drying step include natural drying, ventilation drying, heat drying and reduced pressure drying, and the drying temperature (heating temperature) of the polymerizable liquid crystal compound used in the drying step is It can be appropriately determined according to the type, the type of the solvent, its boiling point and its amount, and the like.

Subsequently, in the obtained dry coating film, a liquid crystal cured film, which is a polymer of the polymerizable liquid crystal compound present in a desired alignment state, is formed by polymerizing the polymerizable liquid crystal compound by light irradiation while maintaining the alignment state of the polymerizable liquid crystal compound. . As the polymerization method, a photopolymerization method is usually used. In photopolymerization, as the light irradiated to the dry coating film, the kind of photopolymerization initiator contained in the dried coating film, the kind of polymerizable liquid crystal compound (particularly, the kind of polymerizable group the polymerizable liquid crystal compound has) and the amount thereof is appropriately selected according to Specific examples thereof include one or more types of light selected from the group consisting of visible light, ultraviolet light, infrared light, X-rays, α-rays, β-rays and γ-rays, and active energy rays such as active electron beams. Among them, ultraviolet light is preferable because it is easy to control the progress of the polymerization reaction and that a photopolymerization apparatus widely used in the art can be used, and polymerization is performed so that photopolymerization is possible with ultraviolet light. It is preferable to select the type of polymerizable liquid crystal compound or photopolymerization initiator contained in the liquid crystal composition. In the case of polymerization, the polymerization temperature can also be controlled by light irradiation while cooling the dried coating film with an appropriate cooling means. When the polymerizable liquid crystal compound is polymerized at a lower temperature by employing such a cooling means, a liquid crystal cured film can be appropriately formed even if a substrate having relatively low heat resistance is used. In addition, it is also possible to promote the polymerization reaction by increasing the polymerization temperature within a range in which problems due to heat during light irradiation (deformation due to heat of the base film, etc.) do not occur. At the time of photopolymerization, a patterned cured film can also be obtained by masking or developing.

As the light source of the active energy ray, for example, a low pressure mercury lamp, a medium pressure mercury lamp, a high pressure mercury lamp, an ultra-high pressure mercury lamp, a xenon lamp, a halogen lamp, a carbon arc lamp, a tungsten lamp, a gallium lamp, an excimer laser, a wavelength range of 380 An LED light source emitting light of -440 nm, a chemical lamp, a black light lamp, a microwave excited mercury lamp, a metal halide lamp, and the like are exemplified.

The ultraviolet irradiation intensity is usually 10 to 3,000 mW/cm 2 . The ultraviolet irradiation intensity is preferably an intensity in a wavelength range effective for activating the photopolymerization initiator. The light irradiation time is usually 0.1 second to 10 minutes, preferably 0.1 second to 5 minutes, more preferably 0.1 second to 3 minutes, still more preferably 0.1 second to 1 minute. 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 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 still more preferably 2.5 μm or less. If the film thickness of the liquid crystal cured film (x) is within the above range, predetermined optical properties are easily exhibited, and generation of strain at the inflection point is easily suppressed when bending is repeated. The thickness of the liquid crystal cured film (x) can be measured using an interference film thickness meter, a laser microscope, or a stylus film thickness meter.

The liquid crystal cured film (x) may be formed on an alignment film. The alignment film has an orientation regulating force that aligns a polymerizable liquid crystal compound in a desired direction. By forming a liquid crystal cured film using a horizontal alignment film having an orientation regulating force for orienting the polymerizable liquid crystal compound in the horizontal direction or a vertical alignment film having an orientation regulating force for orienting the polymerizable liquid crystal compound in the vertical direction, the polymerizable liquid crystal compound can be formed with high precision in a desired direction. It can be aligned, and a liquid crystal cured film exhibiting excellent optical properties when incorporated in a display device or the like can be obtained. The alignment control force can be arbitrarily adjusted depending on 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 depending on polarized light irradiation conditions and the like.

As the alignment film, it is preferable to have solvent resistance that does not dissolve when the polymerizable liquid crystal composition is applied or the like, and also has heat resistance in heat treatment for solvent removal and alignment of the polymerizable liquid crystal compound. Examples of the alignment film include an alignment film made of an orientation polymer, a photo alignment film, a groove alignment film having a concavo-convex pattern or a plurality of grooves on the surface, a stretched film stretched in the orientation direction, and the like, from the viewpoint of accuracy and quality of orientation angle. A photo alignment layer is preferred.

Examples of the orienting polymer include polyamides and gelatins having an amide bond in the molecule, polyimide having an imide bond in the molecule, and polyamic acid that is a hydrolyzate thereof, polyvinyl alcohol, alkyl-modified polyvinyl alcohol, and polyacrylic acid. amides, polyoxazoles, polyethyleneimines, polystyrenes, polyvinylpyrrolidones, polyacrylic acids, and polyacrylic acid esters. Especially, polyvinyl alcohol is preferable. An orientation polymer can be used individually or in combination of 2 or more types.

An alignment film containing an alignment polymer is usually obtained 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 on which an alignment film is to be formed, such as a base film, and removing the solvent, or It is obtained by applying an orienting polymer composition to a substrate, removing the solvent, and rubbing (rubbing method). Examples of the solvent include the same solvents as those previously exemplified as solvents that can be used for the polymerizable liquid crystal composition.

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

As the orientation polymer composition, you may use a commercially available orientation film material as it is. Commercially available alignment film materials include Saneva (registered trademark, manufactured by Nissan Chemical Industries, Ltd.), Optimer (registered trademark, manufactured by JSR Corporation), and the like.

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

Methods for removing the solvent contained in the orientation polymer composition include natural drying, air drying, heat drying and reduced pressure drying.

In order to impart orientation regulating force to the alignment film, rubbing treatment can be performed as needed (rubbing method). As a method for imparting an orientation regulating force by the rubbing method, a method in which a rubbing cloth is wound and a rotating rubbing roll is brought into contact with a film of an orienting polymer formed on the surface of a substrate by applying an orienting polymer composition to a substrate and annealing thereto can be cited. . When performing the rubbing treatment, if masking is performed, a plurality of regions (patterns) having different orientation directions may be formed on the alignment film.

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

A photoreactive group means a group which generates liquid-crystal orientation ability by light-irradiating. Specifically, a group involved in a photoreaction that is a source of orientation induction of molecules generated by light irradiation or a liquid crystal alignment ability such as an isomerization reaction, a dimerization reaction, a photocrosslinking reaction, or a photolysis reaction is exemplified. Especially, the group involved in dimerization reaction or photocrosslinking reaction is preferable at the point which is excellent in orientation. As the photoreactive group, a group having an unsaturated bond, particularly a double bond is preferable, and a carbon-carbon double bond (C=C bond), a carbon-nitrogen double bond (C=N bond), a nitrogen-nitrogen double bond (N=N bond) and a group having at least one selected from the group consisting of a carbon-oxygen double bond (C=O bond) is 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 stilbazolium group, a chalcone group, and a cinnamoyl group.

Examples of the photoreactive group having a C=N bond include groups having structures such as aromatic Schiff base and 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 biazo group, a formazan group, and a group having an azoxybenzene structure. A benzophenone group, a coumarin group, an anthraquinone group, a maleimide group, etc. are mentioned as a photoreactive group which has a C=O bond. 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, or a halogenated alkyl group.

Among them, the photoreactive group involved in the photodimerization reaction is preferable, and the amount of polarized light irradiation required for photo-alignment is relatively small, and a photo-alignment film having excellent thermal stability and time-lapse stability is easy to be obtained. A cinnamoyl group and a chalcone group are preferred. In particular, when the liquid crystal curing film is formed of a polymerizable liquid crystal compound having a (meth)acryloyloxy group as a polymerizable group, a cinnamoyl group having a photoreactive group forming an alignment film and having a cinnamic acid structure at the end of the polymer side chain. Adhesion with a liquid crystal cured film can be improved by using what has.

The solvent included in the composition for forming a photo-alignment layer includes the same solvents as those previously exemplified as solvents that can be used in the polymerizable liquid crystal composition, and can be appropriately selected depending on the solubility of the polymer or monomer having a photoreactive group.

The content of the polymer or monomer having a photoreactive group in the composition for forming a photo-alignment layer can be appropriately adjusted according to the type of polymer or monomer or the desired thickness of the photo-alignment layer, but is at least 0.2 mass relative to the mass of the composition for forming a photo-alignment layer. It is preferable to set it as %, and the range of 0.3-10 mass % is more preferable. The composition for forming a photo-alignment layer may contain a polymer material such as polyvinyl alcohol or polyimide, or a photosensitizer, as long as the characteristics of the photo-alignment layer are not significantly impaired.

As a method of applying the composition for forming a photo-alignment layer to the surface on which an alignment layer is to be formed, the same method as the method of applying an alignment polymer composition may be used. Methods for removing the solvent from the applied composition for forming a photo-alignment layer include, for example, a natural drying method, an air drying method, a heat drying method, and a vacuum drying method.

In order to irradiate polarized light, the composition for forming a photo-alignment film applied on a substrate film may be directly irradiated with polarized light UV to a composition from which the solvent has been removed, or a type of irradiating polarized light from the base film side and transmitting the polarized light may be used. do. Further, the polarized light is particularly preferably substantially parallel light. The wavelength of the polarized light to be irradiated is preferably in a wavelength range in which the photoreactive group of a polymer or monomer having a photoreactive group can absorb light energy. Specifically, UV (ultraviolet rays) in the wavelength range of 250 to 400 nm is particularly preferred. Examples of light sources used for the polarized light irradiation include xenon lamps, high-pressure mercury lamps, ultra-high pressure mercury lamps, metal halide lamps, ultraviolet lasers such as KrF and ArF, and high-pressure mercury lamps, ultra-high pressure mercury lamps, and metal halide lamps. is more preferable. Among these, high-pressure mercury lamps, ultra-high-pressure mercury lamps, and metal halide lamps are preferable because they have high emission intensity of ultraviolet light with a wavelength of 313 nm. Polarized UV can be irradiated by irradiating light from the light source through an appropriate polarizer. As such a polarizer, a polarization filter, a polarization prism such as Glenn Thomson or Glenn Taylor, or a wire grid type polarizer can be used.

Moreover, if masking is performed when rubbing or polarized light irradiation is performed, a plurality of regions (patterns) having different directions of liquid crystal orientation can also be formed.

A groove alignment film is a film having a concavo-convex pattern or a plurality of grooves on the surface of the film. When a polymerizable liquid crystal compound is applied to a film having a plurality of linear grooves parallel to each other at equal intervals, liquid crystal molecules are oriented in a direction along the grooves.

As a method of obtaining a groove alignment film, after exposure through an exposure mask having a pattern-shaped slit on the surface of the photosensitive polyimide film, developing and rinsing are performed to form a concavo-convex pattern, and a plate-shaped master having grooves on the surface , a method of forming a layer of UV curable resin before curing, transferring the formed resin layer to a substrate or the like and then curing it, and a roll shape having a plurality of grooves in a film of UV curable resin before curing formed on the surface on which an alignment film is to be formed A method of forming irregularities by pressing a disk against and then curing, and the like are exemplified.

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

(polarizer)

The polarizer constituting the optical layered body 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 polyvinyl acetate-based resin can be used. Examples of the polyvinyl acetate-based resin include polyvinyl acetate, which is a homopolymer of vinyl acetate, and copolymers of vinyl acetate and other monomers copolymerizable therewith (for example, ethylene-vinyl acetate copolymers).

Examples of the other monomer copolymerizable with vinyl acetate include unsaturated carboxylic acids, olefins, vinyl ethers, unsaturated sulfonic acids, and acrylamides having an ammonium group.

The degree of saponification of the polyvinyl alcohol-based resin is usually about 85 to 100 mol%, preferably 98 mol% or more. The polyvinyl alcohol-based resin may be modified, and for example, polyvinyl formal and 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 1,500 to 5,000.

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

A polarizer is usually the process of uniaxially stretching such a polyvinyl alcohol-type resin film, the process of adsorbing a dichroic pigment by dyeing a polyvinyl alcohol-type resin film with a dichroic pigment, and the polyvinyl alcohol to which the dichromatic pigment was adsorbed It is manufactured through the process of processing a system resin film with an aqueous solution of boric acid, and the process of performing a water washing treatment after the process with an aqueous solution of boric acid. Further, by dyeing the polyvinyl alcohol-based resin film with a dichromatic dye, the dichromatic dye is included in the polyvinyl alcohol-based resin film. When a polarizer is manufactured by this manufacturing method, the polarizer becomes a stretched polyvinyl alcohol-based resin film containing a dichromatic dye.

Uniaxial stretching of the polyvinyl alcohol-based resin film may be performed before dyeing of the dichroic dye, may be performed simultaneously with dyeing, or may be performed after dyeing. When uniaxial stretching is performed after dyeing, this uniaxial stretching may be performed before boric acid treatment or may be performed during boric acid treatment. It is also possible to perform uniaxial stretching in a plurality of these steps. In uniaxial stretching, it may be uniaxially stretched between rolls having different circumferential speeds, or it may be uniaxially stretched using a hot roll. Moreover, uniaxial stretching may be dry stretching performed in air, or wet stretching performed in a state in which a polyvinyl alcohol-based resin film is swollen using a solvent. The stretching 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 polarizer. Moreover, a draw ratio is 4.5 times or more normally from a viewpoint of expressing the function as a polarizer. Time-dependent deformation|transformation of a polarizer can be suppressed by making a draw ratio into the said range.

As a method of dyeing a polyvinyl alcohol-type resin film with a dichroic dye, the method of immersing a polyvinyl alcohol-type resin film in the aqueous solution containing a dichroic dye is mentioned, for example. As a dichroic dye, iodine or a dichroic dye is used, for example. The dichroic dye includes, for example, a dichroic direct dye composed of a disazo compound such as C. I. DIRECT RED 39, a dichroic direct dye composed of a trisazo, a tetrakisazo compound, and the like. Moreover, it is preferable to perform the immersion process with respect to water before a dyeing process of a polyvinyl alcohol-type resin film.

When using iodine as a dichroic dye, a method of dyeing by immersing a polyvinyl alcohol-based resin film in an aqueous solution containing iodine and potassium iodide is usually adopted.

The content of iodine in this aqueous solution is usually about 0.01 to 1 part by mass per 100 parts by mass of water. Moreover, 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. Moreover, the immersion time (dyeing time) with respect to this aqueous solution is about 20 to 1,800 second normally.

In addition, before immersing the polyvinyl alcohol-based resin film in an aqueous solution containing iodine and potassium iodide, the film may be immersed in water in order to swell and facilitate dyeing. The temperature of this immersion treatment is usually 20 to 80°C, preferably 30 to 60°C, and the immersion time (dyeing time) is usually 20 to 1800 seconds.

On the other hand, in the case of using a dichromatic organic dye as the dichromatic dye, a method of dyeing by immersing a polyvinyl alcohol-based resin film in an aqueous solution containing a water-soluble dichromatic dye is usually employed.

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 × 10 ^-3 to 1 × 10 ^-2 parts by mass. This aqueous solution may contain inorganic salts, such as sodium sulfate, as a dyeing adjuvant. The temperature of the dichroic dye aqueous solution used for dyeing is usually about 20 to 80°C. Moreover, the immersion time (dyeing time) with respect to this aqueous solution is about 10 to 1,800 second normally.

The boric acid treatment after dyeing with the dichromatic dye can be usually performed by a method of immersing the dyed polyvinyl alcohol-based resin film in an aqueous solution of boric acid. The content of boric acid in this aqueous solution of boric acid 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, it is preferable that this aqueous solution of boric acid contains potassium iodide, and the content of potassium iodide in that case is usually about 0.1 to 15 parts by mass per 100 parts by mass of water, preferably 5 to 12 parts by mass. The immersion time in boric acid aqueous solution is usually about 60 to 1,200 seconds, preferably 150 to 600 seconds, more preferably 200 to 400 seconds. The boric acid treatment temperature 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 a method of immersing the polyvinyl alcohol-based resin film treated with boric acid in water. The temperature of the water in the water washing treatment is usually about 5 to 40°C.

Moreover, immersion time is about 1 to 120 second normally.

A drying process is given after water washing, and a polarizer is obtained. Drying treatment 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 process, the water content of the polarizer is reduced to a practical level. The water content is usually about 5 to 20% by mass, and preferably 8 to 15% by mass. When the moisture content is within the above range, a light polarizer having appropriate flexibility and excellent thermal stability can be obtained.

In this way, it is obtained by subjecting a polyvinyl alcohol-based resin film to uniaxial stretching, dyeing with a dichromatic dye, boric acid treatment, water washing and drying.

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

(transparent protective film)

The optical layered body of the present invention includes a transparent protective film bonded to the surface of the polarizer on the opposite side to the retardation film through an adhesive layer. Since the film thickness of the polarizer is thin and its surface is easily damaged, in many cases, protective films are usually provided on both sides of the polarizer to prevent damage or contamination from the outside, but in the optical laminate of the present invention, the polarizer A protective film is not laminated on the surface on the retardation film side of . This makes it possible to obtain a thinner optical laminate having a low 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 equal to or greater than the lower limit, an optical laminate having high transparency and excellent optical properties can be formed. The upper limit of the total light transmittance in the base film is not particularly limited, and may be 100% or less. The total light transmittance can be measured according to JIS K 7361, for example.

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 equal to or less than the above upper limit, when the optical laminate containing the transparent protective film is incorporated in an image display device, the layer constituting the inside of the optical laminate from ultraviolet rays exposed on the viewing side (A polarizer, a liquid crystal cured 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 set 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. 380 nm transmittance can be measured according to a spectrophotometer, for example.

A well-known resin film can be used as a transparent protective film attached to a polarizer through an adhesive bond layer, as long as it satisfies the above total light transmittance and 380 nm transmittance. Examples of the resin capable of constituting the transparent protective film include polyolefins such as polyethylene, polypropylene, and norbornene polymers; Cyclic olefin resin; polyvinyl alcohol; polyethylene terephthalate; Polymethacrylic acid ester; polyacrylic acid ester; cellulose esters such as triacetyl cellulose, diacetyl cellulose, and cellulose acetate propionate; polyethylene naphthalate; polycarbonate; polysulfone; polyethersulfone; polyether ketone; Polyphenylene sulfide, polyphenylene oxide, etc. are mentioned. Such a resin can be formed into a film by a known means such as a solvent casting method or a melt extrusion method. The surface of the transparent protective film may be subjected to surface treatment such as release treatment such as silicone treatment, corona treatment, or plasma treatment.

In one embodiment of the present invention, the transparent protective film has a resistance of preferably 100 g/m2/24 hours or more, more preferably 150 g/m2/24 hours or more, and still more preferably 200 g/m2/24 hours or more. has moisture permeability. If the water vapor permeability of the transparent protective film is equal to or greater than the above lower limit, when an optical laminate is formed by laminating the retardation film and the polarizer using a dry solidification type adhesive, in addition to the base film constituting the retardation film, the dry solidification type can also be obtained from the transparent protective film. The solvent in the adhesive can be efficiently removed. This makes it easy for the deformation in the liquid crystal cured film formed on the base film and the deformation in the optical laminate to follow each other when bent, and the optical laminate in which deformation at the inflection point is less likely to occur even when repeatedly bent. body can be obtained. Moreover, since the time for removing the solvent in an adhesive agent can be shortened compared with the case where only a base film has high water vapor transmission rate, it can be advantageous also in terms of productivity. The upper limit of the water vapor transmission rate 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 water vapor transmission rate of the transparent protective film can be measured by the same method as the water vapor transmission rate of the base film.

When using a transparent protective film having a water vapor transmission rate of 100 g/m 2 /24 hours or more, 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 configuration of the desired optical laminate, but is usually 5 µm to 300 µm, preferably 20 µm to 200 μm, more preferably 20 μm to 150 μm.

Hereinafter, an example of the layer structure of the optical layered body of the present invention is described based on Figs. 1 and 2, but the optical layered body of the present invention is not limited to these aspects.

The optical layered body 100 shown in FIG. 1 includes a retardation film 1, a polarizer 3 laminated on one side of the retardation film with an adhesive layer 2 interposed therebetween, and a phase difference between the polarizer 3 It consists of the transparent protective film 5 laminated|stacked with the adhesive layer 4 interposed on the surface on the opposite side to the film 1. In the optical layered body 100 shown in FIG. 1 , the retardation film 1 consists of a liquid crystal cured film 13 formed on a base film 11 with an orientation film 12 interposed therebetween.

In addition to the retardation film, the polarizer, the transparent protective film, and the adhesive layer for bonding them to each other, the optical laminate of the present invention may be configured to include other layers having various functions that can be incorporated in an image display device or the like, There is no case where another layer is embedded in the layer configuration of the phase difference film/adhesive layer/polarizer/adhesive layer/transparent protective film formed adjacent to each other. As another layer, for example, an adhesive layer for incorporating an optical layered body into an image display device, for example, an optic different from the liquid crystal cured film (x) in which the liquid crystal compound is oriented in the vertical direction with respect to the film surface and a second retardation film comprising a liquid crystal cured film having characteristics.

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

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

The optical layered body of the present invention can be manufactured by bonding the retardation film, the polarizer, and the transparent protective film together through an adhesive agent, respectively. When using a dry solidified adhesive as the adhesive, the dry solidified adhesive is applied/injected to the bonding surface of the retardation film, the polarizer and/or the transparent protective film, and the retardation film/adhesive layer/polarizer/adhesive layer/transparent protective film After forming the laminate, each layer can be bonded by drying and removing the solvent in the adhesive from the laminate and curing the laminate.

This drying treatment and/or removal of the solvent can be carried out, for example, by blowing hot air, and the temperature varies depending on the type of solvent, but is usually 30 to 200 ° C., preferably 35 to 150 ° C. It is preferably in the range of 40 to 100°C, more preferably 50 to 100°C. Moreover, drying time is about 10 second - 30 minutes normally.

Moreover, when using an active energy ray-curable adhesive, an adhesive bond layer is obtained by hardening an active energy ray-curable adhesive by irradiating an active energy ray. The light source of the active energy ray is not particularly limited, but an active energy ray having a luminescence distribution at a wavelength of 400 nm or less is preferable, and an ultraviolet ray is more preferable. Specifically as a light source, a low-pressure mercury-vapor lamp, a medium-pressure mercury-vapor lamp, a high-pressure mercury-vapor lamp, an ultra-high-pressure mercury-vapor lamp, a chemical lamp, a black light lamp, a microwave excited mercury-vapor lamp, and a metal halide lamp are exemplified.

The light irradiation intensity to the active energy ray curable adhesive is appropriately determined depending on the composition of the active energy ray curable adhesive, and is not particularly limited. The irradiation intensity in the wavelength range effective for activation of the polymerization initiator is usually 10 to 3,000 mW/cm 2 am. The light irradiation time for the active energy ray curable adhesive may be appropriately selected according to the active energy ray curable adhesive to be cured, and is not particularly limited, but is usually 0.1 second to 10 minutes, preferably 1 second to 5 minutes, more preferably Preferably it is 5 seconds to 3 minutes, 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/cm 2 .

The optical laminate of the present invention can be continuously manufactured by a roll to roll method. For example, a retardation film comprising a base film wound in a roll shape and a liquid crystal cured film (x) is produced, conveyed while unwinding the retardation film, and an adhesive for adhering each layer is used on the retardation film. It can be manufactured continuously by laminating a separately produced polarizer and a transparent protective film in order, and then curing the adhesive by drying or photocuring.

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 into a roll shape.

Since the optical layered body of the present invention comprising a retardation film and a polarizer may be an elliptically polarizing plate, the present invention includes an elliptically polarizing plate including the optical layered body of the present invention.

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

The elliptically polarizing plate of the present invention can be used for various display devices.

A display device is a device having a display element, and includes a light emitting element or a light emitting device as a light emitting source. As the display device, 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 (eg, a field emission display device (FED) ), surface field emission display (SED)), electronic paper (display devices using electronic ink or electrophoretic devices, plasma displays, projection display devices (e.g., grating light valve (GLV) displays, digital micromirror devices) (DMD) and piezoelectric ceramic displays, etc. The liquid crystal display device includes a transmission type liquid crystal display device, a transflective type liquid crystal display device, a reflection type liquid crystal display device, a direct view type liquid crystal display device, and a projection type liquid crystal display device. These display devices may be either a display device displaying a two-dimensional image or a stereoscopic display device displaying a three-dimensional image. It can be preferably used for display devices and inorganic electroluminescence (EL) display devices, and the laminate of the present invention can be preferably used for liquid crystal display devices and touch panel display devices. By providing the layered product of the present invention that does not occur, favorable image display characteristics can be expressed.

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 elliptically polarizing plate of the present invention.

It is preferable that the flexible image display device having the elliptically polarizing plate of the present invention further has a window and a touch sensor.

A flexible image display device is composed of, for example, a laminate for a flexible image display device and an organic EL display panel, and the laminate for a flexible image display device is disposed on the viewing side with respect to the organic EL display panel, and is configured to be bendable. there is. In addition to the elliptically polarizing plate of the present invention described above, a window, a (touch panel) touch sensor, and the like can be included in the laminate for the flexible image display device. Although the order of lamination is arbitrary, it is preferable to laminate in the order of a window, an elliptically polarizing plate, and a touch sensor from the viewing side, or in the order of a window, a touch sensor, and an elliptically polarizing plate.

When the elliptically polarizing plate is present on the viewing side of the touch sensor, it is difficult to visually recognize the pattern of the touch sensor, and the visibility of the displayed image is improved, which is preferable. Each member can be laminated using an adhesive, pressure-sensitive adhesive, or the like. In addition, the laminate for the flexible image display device may include a light blocking pattern formed on at least one surface of any layer of the window, the elliptically polarizing plate, or the touch sensor.

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

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

Example

Hereinafter, the present invention will be described in more detail by examples. In addition, "%" and "part" in an example mean mass % and mass part, respectively, unless there is particular notice.

[Example 1]

(1) Production of a composition for forming a photo-alignment layer

A composition for forming a photo-alignment film was obtained by mixing 2 parts of polymer (1) having a number average molecular weight of 28000 represented by the following formula and 98 parts of o-xylene, and stirring the resulting mixture at 80°C for 1 hour.

Polymer (1)

[Formula 3]

[Wherein, Me represents a methyl group.]

(2) Preparation of a 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 a polyacrylate compound (leveling agent/BYK-361N; manufactured by BYK-Chemie) (0.12 parts) ), 2-dimethylamino-2-benzyl-1-(4-morpholinophenyl)butan-1-one (photopolymerization initiator/Irgacure 369; manufactured by Ciba Specialty Chemicals) (3.0 parts) and LALOMER LR9000 (manufactured by BASF Japan) (2.0 parts) was mixed. Furthermore, anisole was added so that the solid content concentration might be 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.

In addition, polymeric liquid crystal compound A-1 was synthesized by the method described in Japanese Unexamined Patent Publication No. 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:

[Formula 4]

Polymerizable liquid crystal compound A-2:

[Formula 5]

(3) Production of retardation film

A triacetyl cellulose film (KC4CZ-TAC manufactured by Konica Minolta, 40 µm in thickness) was prepared using a corona treatment device (AGF-B10; manufactured by Kasuga Electric Co., Ltd.) under conditions of an output of 0.3 kW and a processing speed of 3 m/min. treated twice. On the corona-treated surface, the composition for forming a photo-alignment layer was bar-coated, dried at 80 ° C. for 1 minute, and using a polarized UV irradiation device (SPOT CURE SP-7 with a polarizer unit; manufactured by Ushio Electric Co., Ltd.), Polarization UV exposure was performed with a cumulative light amount of 100 mJ/cm 2 to form a photo-alignment film. It was 100 nm as a result of measuring the thickness of the obtained photo-alignment film with the ellipsometer M-220 (made by Nippon Spectroscopy Co., Ltd.).

The water vapor transmission rate and total light transmittance of the triacetyl cellulose film (KC4CZ-TAC) used as the base film of the retardation film were measured according to the following method.

(measurement of moisture permeability)

The water vapor transmission rate [g/(m ² ·24 hr)] of the protective film at a temperature of 40°C and a relative humidity of 90% was measured by the cup method specified in JIS Z 0208. The water vapor transmission rate of the TAC film was 370 g/m 2 /24 hours.

(Measurement of total light transmittance)

In accordance with JIS K7361, the total light transmittance was measured using Hazemeter HM150 manufactured by Murakami Color Technology Laboratory. The total light transmittance of the TAC film was 93%.

Further, as a result of measuring the retardation values [Re(550) and Rth(550)] of the TAC film serving as the substrate at a wavelength of 550 nm, it was approximately zero.

Subsequently, the polymerizable liquid crystal composition (A1) containing the previously prepared polymerizable liquid crystal compound was applied onto the photo-alignment layer 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 Electric Co., Ltd.), ultraviolet rays were irradiated from the surface side to which the polymerizable liquid crystal composition (A1) was applied (integration at a wavelength of 313 nm under a nitrogen atmosphere) Amount of light: 500 mJ/cm 2 ), thereby forming a retardation film which is a laminate composed of a triacetyl cellulose film (base film)/light alignment film/liquid crystal cured film. It was 2.3 micrometers as a result of measuring the thickness of the obtained liquid crystal cured film with the laser microscope (LEXT; made by Olympus Corporation).

As a result of measuring the retardation value of the obtained retardation film at a wavelength of 550 nm, it was Re(550) = 140 nm. Further, as a result of measuring the retardation values of the obtained retardation film at a wavelength of 450 nm and at a wavelength of 650 nm, Re(450)/Re(550) = 0.85 and Re(650)/Re(550) = 1.05.

(4) Fabrication of polarizer (iodine PVA type polarizer)

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

(5) Manufacture of optical laminate

The retardation film and polarizer prepared above, and a triacetyl cellulose film (TAC: "KC4UY" manufactured by Konica Minolta Opto Co., Ltd.) as a transparent protective film were laminated in this order, and the triacetyl cellulose side of the retardation film and the polarizer Then, a water-based dry solidified adhesive is injected so that the triacetyl cellulose of the transparent protective film is in contact with the polarizer on the opposite side of the retardation film, so that the absorption axis of the polarizer and the slow axis of the liquid crystal cured film in the retardation film are 45 It bonded together with a nip roll so that it might become °. Optical laminate I consisting of a liquid crystal cured film / optical alignment film / base film / adhesive layer / polarizer / adhesive layer / transparent protective film by drying at 60 ° C. for 2 minutes while maintaining the tension of the obtained bond at 430 N / m (ellipse polarizer) was obtained.

In addition, the water-based dry solidified adhesive is 100 parts of water, 3 parts of carboxyl group-modified polyvinyl alcohol (Kurarepoval KL318; manufactured by Kuraray Co., Ltd.), and a water-soluble polyamide epoxy resin (Sumirez Resin 650; Sumika Chemtex) Co., Ltd. product, aqueous solution of 30% of solid content concentration) 1.5 part was added and prepared.

As a result of measuring the water vapor transmission rate and total light transmittance of the transparent protective film in the same manner as in the measurement method for the base film described above, the water vapor transmission rate was 350 g/m 2 /24 hours and the total light transmittance was 93%.

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

(6) Evaluation of the optical laminate

(i) evaluation of flexibility

The evaluation of the flexibility was performed as follows using the method of General Test Methods for Paints-Flexibility (Cylindrical Mandrel Method) described in JIS-K-5600-5-1.

The optical laminate was cut into a size of 25 mm x 200 mm, using a cylindrical mandrel method bending resistance tester type II (manufactured by TP Kiyon Co., Ltd.) under conditions of a temperature of 25°C and a relative humidity of 55% RH, with a diameter of 6 mm. A flexibility test was conducted by winding the liquid crystal cured layer of the retardation film to the outside around a mandrel rod having a radius of curvature (R) = 3 mm. Using the optical laminate after the test, visual confirmation was performed in a darkroom environment with light transmitted through illumination, and as a result of observing the occurrence of cracks, those in which cracks were visually recognized were rated as "X", and those in which cracks were not visually recognized were marked as "○". 」 was judged. A result is shown in Table 1.

(ii) Evaluation of oblique reflectance

The oblique reflectance of the optical layered body was measured as follows. The side derived from the retardation film of the optical laminate (in the case of optical laminate I, the liquid crystal cured film) and the reflector (mirror surface aluminum plate) were bonded together using an acrylic adhesive to prepare a measurement sample.

Using a spectrophotometer (CM3700A manufactured by Konica Minolta Co., Ltd.), light from a D65 light source was incident on the measurement sample from an 8° direction, and an oblique reflectance (reflection Y value) was measured. It was set as ○ when the oblique reflectance was 1% or more and less than 6%, △ when it was 6% or more and less than 8%, and × when it was 8% or more. A result is shown in Table 1.

(iii) Evaluation of heat resistance test

The side derived from the retardation film of the optical laminated body and the glass plate were bonded together using an acrylic adhesive to prepare a measurement sample.

The obtained measurement sample was put into an oven at 85 ° C., and after 500 hours, 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 using KOBRA-WR manufactured by Oji Instruments Co., Ltd. measured. When the change amount was 1 nm or more and less than 3 nm, it was set as ○, when it was 3 nm or more and less than 5 nm, it was set as △, and when it was 5 nm or more, it was set as ×. A result is shown in Table 1.

[Example 2]

When bonding the retardation film and the polarizer, except that the liquid crystal cured film side was bonded to the polarizer, in the same manner as in Example 1, consisting of a base film / light alignment film / liquid crystal cured film / adhesive layer / polarizer / adhesive layer / transparent protective film An optical laminate was produced and evaluated. A result is shown in Table 1.

[Example 3]

As the transparent protective film, a polymethyl methacrylate resin film (manufactured by Sumitomo Chemical Co., Ltd., moisture permeability: 50 g/m 2 /24 hours, total light transmittance: 93%, 380 nm transmittance: 6%) was used in the same manner as in Example 1. Thus, an optical laminate composed of a base film/light alignment film/liquid crystal cured film/adhesive layer/polarizer/adhesive layer/transparent protective film was prepared and evaluated.

A result is shown in Table 1.

[Example 4]

As a transparent protective film, 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: 8%) to which an ultraviolet absorber was added was used as a transparent protective film. Except for that, it carried out similarly to Example 1, the optical laminated body which consists of base film/light alignment film/liquid crystal cured film/adhesive layer/polarizer/adhesive layer/transparent protective film was manufactured and evaluated. A result is shown in Table 1.

[Comparative Example 1]

As a base film, the TAC film used as the transparent protective film of Example 1 was used, and in the manufacturing process of the optical laminate, the transparent protective film and the polarizer were bonded together with the same water-based dry solidifying adhesive as those used in Example 1. , Using an acrylic pressure-sensitive adhesive having a thickness after curing of 5 μm, the surface of the polarizer on which the transparent protective film is not laminated and the liquid crystal cured film side of the retardation film are bonded together, except that the triacetyl cellulose film serving as the base film is peeled off. It carried out similarly to Example 1, the optical laminated body which consists of a light alignment film/liquid crystal cured film/adhesive layer/polarizer/adhesive layer/transparent protective film was manufactured and evaluated. A result is shown in Table 1.

[Comparative Example 2]

In the same manner as in Comparative Example 1 except that the triacetyl cellulose, which is the base film, was not peeled off, an optical laminate composed of a base film/light alignment film/liquid crystal cured film/pressure-sensitive adhesive layer/polarizer/adhesive layer/transparent protective film was prepared, Evaluation was conducted. A result is shown in Table 1.

[Reference Example 1]

Example 4 except that a cycloolefin polymer film (COP; ZF-14; manufactured by Nippon Zeon Co., Ltd., moisture permeability: 13 g/m/24 hours, total light transmittance: 92%, 380 nm transmittance: 90%) was used as the base film. Similarly, the optical laminated body which consists of base film/light alignment film/liquid crystal cured film/adhesive layer/polarizer/adhesive layer/transparent protective film was manufactured and evaluated. A result is shown in Table 1.

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

1: retardation film
2: adhesive layer
3: Polarizer
4: adhesive layer
5: transparent protective film
11: base film
12: alignment layer
13: liquid crystal curing film
100: optical laminate

Claims (14)

An optical laminate comprising a retardation film, a polarizer and a transparent protective film in this order,
The retardation film has a base film having a moisture permeability of 100 g/m/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 formulas (1) and (2):
Re(450)/Re(550) ≤ 1.00 (1)
1.00 ≤ Re(650)/Re(550) (2)
[Wherein, Re(λ) represents the in-plane retardation value at the wavelength λ]
It is made of a liquid crystal cured film that satisfies as a single layer,
The polarizer is composed of a polyvinyl alcohol-based resin film containing a dichromatic 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 comprising the retardation film, the polarizer, and the transparent protective film adjoining each other via an adhesive layer. According to claim 1,
The base film has a total light transmittance of 90% or more, and an absolute value of a retardation value Rth (550) in the thickness direction for 550 nm light is 5 nm or less. According to claim 1 or 2,
The optical layered body wherein the retardation film has a photo-alignment film having a thickness of 10 nm or more and 1000 nm or less between the base film and the liquid crystal cured film. According to any one of claims 1 to 3,
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 and 400 nm. According to any one of claims 1 to 4,
The liquid crystal cured film has the following formula (3):
100 nm ≤ Re(550) ≤ 170 nm (3)
[Wherein, Re(λ) represents the in-plane retardation value at the wavelength λ]
An optical laminate that satisfies According to any one of claims 1 to 5,
The optical laminate, wherein the transparent protective film has a moisture permeability of 100 g/m 2 /24 hours or more. According to any one of claims 1 to 6,
The adhesive layer is a layer formed of a dry solidified adhesive, an optical laminate. According to claim 7,
The dry solidified adhesive comprises polyvinyl alcohol, an optical laminate. According to any one of claims 1 to 8,
An optical laminate in which retardation film is in contact with an adhesive layer for bonding retardation film and polarizer together from the side of the liquid crystal cured film. An optical laminate roll formed by winding the optical laminate according to any one of claims 1 to 9. An elliptically polarizing plate comprising the optical laminate according to any one of claims 1 to 9. An organic EL display device comprising the elliptically polarizing plate according to claim 11. A flexible image display device comprising the elliptically polarizing plate according to claim 11. According to claim 13,
A flexible image display device further comprising a window and a touch sensor.

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