CN120722483A - Optical laminate - Google Patents

Abstract

The present invention provides an optical laminate with excellent interlayer adhesion and durability. The optical laminate comprises, in order, a polarizing film, an adhesive layer, and a liquid crystal retardation film adjacent to the adhesive layer. The polarizing film is a cured layer of a polymerizable liquid crystal composition containing a polymerizable liquid crystal compound and a dichroic dye, and the adhesive layer is a cured layer of an active energy ray-curable adhesive composition containing the following curable compounds: a) a urethane (meth)acrylate having two or fewer (meth)acryloyl groups in the molecule; b) a (meth)acrylate having no aromatic ring and a hydroxyl group in the molecule; and c) a (meth)acrylate having no hydroxyl group and two or more aromatic rings in the molecule.

Description

Optical laminate

Technical Field

The present invention relates to an optical laminate, and more particularly, to an optical laminate comprising a polarizing film, an adhesive layer, and a liquid crystal retardation film adjacent to the adhesive layer in this order.

Background

Image display devices such as organic EL display devices include a large number of optical members such as polarizing plates and retardation plates, and adhesives are widely used for bonding these members. For example, patent document 1 discloses a reflective circularly polarized light separation element in which a cholesteric resin layer and a 1/4 wave plate cured adhesive layer are bonded as a brightness enhancing film.

Prior art literature

Patent literature

Patent document 1 Japanese patent laid-open publication No. 2011-112720

Disclosure of Invention

Problems to be solved by the invention

In recent years, with the demand for thinning of image display panels and the like, a retardation film or a polarizing film of a film formed from a composition containing a liquid crystal compound has been used as a constituent member thereof. However, in an optical laminate including a retardation film formed from a composition containing such a liquid crystal compound, adhesion between layers and durability under high temperature conditions may be poor.

The purpose of the present invention is to provide an optical laminate which has excellent interlayer adhesion and durability.

Means for solving the problems

The present inventors have conducted intensive studies to solve the above problems, and as a result, have completed the present invention. That is, the present invention includes the following preferred embodiments.

[1] An optical laminate comprising, in order, a polarizing film, an adhesive layer, and a liquid crystal retardation film adjacent to the adhesive layer,

The polarizing film is a cured layer of a polymerizable liquid crystal composition containing a polymerizable liquid crystal compound and a dichroic dye,

The adhesive layer is a cured product layer of an active energy ray-curable adhesive composition containing a curable compound,

A) Urethane (meth) acrylate having 2 or less (meth) acryloyl groups in the molecule;

b) (meth) acrylic acid ester having no aromatic ring in the molecule and having a hydroxyl group, and

C) (meth) acrylic acid esters having not hydroxyl groups in the molecule but more than 2 aromatic rings.

[2] The optical laminate according to the item [1], wherein the adhesive composition further comprises d) a (meth) acrylate having an aromatic ring and a hydroxyl group in the molecule.

[3] The optical laminate according to [1] or [2], wherein the adhesive composition contains 1 to 30 parts by mass of a) a urethane (meth) acrylate having 2 or less (meth) acryloyl groups in a molecule, based on 100 parts by mass of the total amount of the curable compounds contained in the adhesive composition.

[4] The optical laminate according to any one of [1] to [3], wherein the adhesive composition contains 15 to 60 parts by mass of the (meth) acrylate having no aromatic ring in the molecule and a hydroxyl group, based on 100 parts by mass of the total curable compound contained in the adhesive composition.

[5] The optical laminate according to any one of [1] to [4], wherein the adhesive composition contains 10 to 60 parts by mass of a (meth) acrylate having 2 or more aromatic rings and no hydroxyl group in a molecule per 100 parts by mass of a total amount of the curable compounds contained in the adhesive composition.

[6] The optical laminate according to item [2], wherein the adhesive composition contains 3 to 40 parts by mass of d) a (meth) acrylate having an aromatic ring and a hydroxyl group in a molecule, based on 100 parts by mass of the total amount of the curable compounds contained in the adhesive composition.

[7] The optical laminate according to any one of the above [1] to [6], wherein the adhesive composition contains 0.5 to 10 parts by mass of a polymerization initiator per 100 parts by mass of the total amount of the curable compounds contained in the adhesive composition.

[8] The optical laminate according to item [7], wherein the polymerization initiator has a molar absorption coefficient of 10L/mol ^-1·cm^-1 or more at a light source wavelength of 400nm in an acetonitrile solvent.

[9] The optical laminate according to any one of the above [1] to [8], wherein a hard coat layer is further contained between the polarizing film and the adhesive layer.

[10] The optical laminate according to any one of the above [1] to [9], which comprises a polarizing film, an alignment film, a hard coat layer, an adhesive layer and a liquid crystal retardation film in a manner of being adjacent to each other in this order.

[11] The optical laminate according to [9] or [10], wherein when the in-plane average refractive index of the hard coat layer is n1, the in-plane average refractive index of the liquid crystal retardation film is n2, and the in-plane average refractive index of the adhesive layer is n3, the following formula is satisfied:

|(n1×n2)^1/2-n3|≤0.018。

effects of the invention

According to the present invention, an optical laminate excellent in adhesion between layers and durability can be provided.

Detailed Description

Hereinafter, embodiments of the present invention will be described in detail. The scope of the present invention is not limited to the embodiments described herein, and various modifications may be made without departing from the scope of the present invention.

An optical laminate of the present invention comprises, in order, a polarizing film, an adhesive layer, and a liquid crystal retardation film adjacent to the adhesive layer. The adhesive layer (hereinafter, also referred to as "adhesive layer (1)") constituting the optical laminate of the present invention is a cured product layer of an active energy ray-curable adhesive composition containing,

A) Urethane (meth) acrylate having 2 or less (meth) acryloyl groups in the molecule;

b) (meth) acrylic acid ester having no aromatic ring in the molecule and having a hydroxyl group, and

C) (meth) acrylic acid esters having not hydroxyl groups in the molecule but more than 2 aromatic rings.

In the present specification, (meth) acrylate means acrylate or methacrylate, and (meth) acryl means acryl or methacryl.

Conventionally, many circularly polarizing plates are formed by bonding a phase difference film and a polarizing film via an adhesive layer. However, in the case where the retardation film is a liquid crystal retardation film formed of a composition containing a liquid crystal compound, there is a case where the retardation value is reduced under high temperature conditions. The present inventors have found that the reduction of the phase difference value under high temperature conditions can be effectively suppressed by using the adhesive layer (1) formed from the active energy ray-curable adhesive composition containing the specific curable compounds of a) to c) as an adhesive layer for bonding the liquid crystal retardation film to other layers. Hereinafter, in the present specification, the effect of suppressing the decrease in the phase difference value of the phase difference film under high temperature conditions is expressed as durability (excellent) or the like.

< Adhesive layer >

The adhesive layer (1) adjacent to the liquid crystal retardation film is formed of an active energy ray-curable adhesive composition (hereinafter, also referred to simply as "adhesive composition (1)") containing the curable compounds of a) to c). In the adhesive composition (1), a) a urethane (meth) acrylate having 2 or less (meth) acryloyl groups in a molecule (hereinafter, also referred to as "urethane (meth) acrylate (a)") is a curable compound capable of functioning as a base polymer for forming the adhesive layer (1). Urethane (meth) acrylate generally refers to the reaction product of an isocyanate compound, a polyol compound, and a (meth) acrylate compound. The urethane (meth) acrylate (a) has 2 or less, that is, usually 1 or 2 (meth) acryl groups in the molecule. If the number of (meth) acryloyl groups is 2, a crosslinked structure is easily formed, and the adhesion of the adhesive layer (1) can be improved and appropriate toughness can be imparted, so that a difunctional urethane (meth) acrylate having 2 (meth) acryloyl groups in the molecule is preferable as the urethane (meth) acrylate (a).

The urethane (meth) acrylate (a) is not particularly limited as long as it has 2 or less (meth) acryloyl groups in the molecule, and known urethane (meth) acrylate compounds can be used. Specifically, examples thereof include a terminal isocyanate urethane prepolymer obtained by reacting a polyol compound such as polyester or polyether with a polyvalent isocyanate compound (for example, 2, 4-toluene diisocyanate, 2, 6-toluene diisocyanate, 1, 3-xylylene diisocyanate, 1, 4-xylylene diisocyanate, diphenylmethane 4, 4-diisocyanate, etc.), and a terminal isocyanate urethane prepolymer obtained by reacting a (meth) acrylate having a hydroxyl group (for example, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, polyethylene glycol (meth) acrylate, etc.). As the urethane (meth) acrylate (a), only 1 kind may be used, or 2 or more kinds may be used in combination. Further, as the urethane (meth) acrylate (a), commercially available products can be used. In the present specification, even when a (meth) acrylate compound having 2 or less (meth) acryloyl groups in a molecule has, for example, a urethane bond and a hydroxyl group (hydroxyl group), the (meth) acrylate is classified as a urethane (meth) acrylate (a) as long as it has a urethane bond.

The weight average molecular weight (Mw) of the urethane (meth) acrylate (a) is preferably 300 or more, more preferably 400 or more, further preferably 500 or more, particularly preferably 600 or more, preferably 50,000 or less, more preferably 30,000 or less, further preferably 10,000 or less, further preferably 5,000 or less, particularly preferably 3,000 or less, particularly preferably 2,000 or less, in terms of polystyrene conversion. If the Mw of the urethane (meth) acrylate (a) falls within the above range, the adhesion to the layer adjacent to the adhesive layer (1) is easily improved. In addition, by controlling the molecular weight of the urethane (meth) acrylate (a), the effect of suppressing the decrease in the retardation value of the liquid crystal retardation film in a high-temperature environment can be further improved. The weight average molecular weight can be measured by, for example, gel Permeation Chromatography (GPC).

The viscosity (40 ℃) of the urethane (meth) acrylate (a) is preferably 10,000 to 100,000mpa·s, more preferably 20,000 to 70,000mpa·s, and still more preferably 40,000 to 60,000mpa·s. If the viscosity of the urethane (meth) acrylate (a) is within the above range, the viscosity of the adhesive composition (1) can be easily controlled, and good coatability can be imparted to the adhesive composition (1). The viscosity of the urethane (meth) acrylate (a) can be measured, for example, by an E-type viscometer.

The content of the urethane (meth) acrylate (a) in the adhesive composition (1) is preferably 1 to 30 parts by mass, more preferably 3 to 25 parts by mass, and even more preferably 5 to 20 parts by mass, based on 100 parts by mass of the total amount of the curable compounds contained in the adhesive composition (1). If the content of the urethane (meth) acrylate (a) is within the above range, the adhesion of the obtained adhesive layer (1) can be improved. In addition, the viscosity of the adhesive composition (1) can be easily adjusted, and good coatability can be imparted to the adhesive composition (1). When the urethane (meth) acrylate (a) is contained in an amount of 2 or more, the total content of these is preferably within the above range.

In the adhesive composition (1), a (meth) acrylate having no aromatic ring in the molecule and a hydroxyl group (hereinafter, also referred to as "hydroxyl group-containing (meth) acrylate (b)") is preferably capable of functioning as an adhesion imparting agent in the adhesive layer (1). The number of hydroxyl groups in the hydroxyl group-containing (meth) acrylate (b) is usually 1 to 3, preferably 1 to 2, more preferably 1, in the molecule. The number of (meth) acryloyl groups in the hydroxyl group-containing (meth) acrylate (b) may be, for example, 1 to 6, preferably 1 to 2, and in a preferred embodiment of the present invention, 1. The hydroxyl group-containing (meth) acrylate (b) is not particularly limited, and may be selected from known hydroxyl group-containing (meth) acrylate compounds. Specifically, examples thereof include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, and the like, hydroxyalkyl (meth) acrylate, 2-hydroxyethyl acryl phosphate, 2- (meth) acryloyloxyethyl-2-hydroxypropyl phthalate, caprolactone-modified 2-hydroxyethyl (meth) acrylate, dipropylene glycol (meth) acrylate, fatty acid-modified glycidyl (meth) acrylate, polyethylene glycol mono (meth) acrylate, polypropylene glycol mono (meth) acrylate, 2-hydroxy-3- (meth) acryloyloxypropyl (meth) acrylate, glycerol di (meth) acrylate, 2-hydroxy-3-acryloyloxypropyl methacrylate, pentaerythritol tri (meth) acrylate, caprolactone-modified pentaerythritol tri (meth) acrylate, ethylene oxide-modified pentaerythritol tri (meth) acrylate, dipentaerythritol penta (meth) acrylate, caprolactone-modified dipentaerythritol penta (meth) acrylate, ethylene oxide-modified dipentaerythritol (meth) acrylate, and the like. As the hydroxyl group-containing (meth) acrylic acid ester (b), only 1 species may be used, or 2 or more species may be used in combination.

The content of the hydroxyl group-containing (meth) acrylate (b) in the adhesive composition (1) is preferably 15 to 60 parts by mass, more preferably 20 to 55 parts by mass, and even more preferably 25 to 50 parts by mass, relative to 100 parts by mass of the total amount of the curable compounds contained in the adhesive composition (1). When the content of the hydroxyl group-containing (meth) acrylate (b) is within the above range, the adhesion of the resulting adhesive layer (1) can be improved. In addition, in the relationship between the layers adjacent to the retardation film or the like, the increase in reflectance can be suppressed. In addition, the viscosity of the adhesive composition (1) can be easily adjusted, and good coatability can be imparted to the adhesive composition (1). On the other hand, when the content of the (meth) acrylic acid ester (b) is too small, the adhesion tends to be low. When the hydroxyl group-containing (meth) acrylate (b) is contained in an amount of 2 or more, the total content thereof is preferably within the above range.

The adhesive composition (1) contains c) a (meth) acrylate having no hydroxyl group in the molecule and having 2 or more aromatic rings (hereinafter, also referred to as "aromatic ring-containing (meth) acrylate (c)"). If the adhesive composition (1) contains the aromatic ring-containing (meth) acrylate (c), the effect of suppressing the decrease in the phase difference value under high temperature conditions is excellent in the optical laminate comprising the liquid crystal phase difference film. The reason for this is not necessarily limited, but is presumed as follows. In the optical laminate in which the adhesive layer (1) is present adjacent to the liquid crystal retardation film, the aromatic ring-containing (meth) acrylate (c) is transferred from the adhesive layer (1) to the liquid crystal retardation film. Since the aromatic ring-containing (meth) acrylate (c) contains 2 or more aromatic rings, it is considered that the compound has a relatively high electron density and thus acts to increase the phase difference value of the liquid crystal retardation film when transferred to the liquid crystal retardation film. Therefore, it is estimated that the decrease in the phase difference value under high temperature conditions is offset by the increase in the phase difference value caused by the transfer of the aromatic ring-containing (meth) acrylate (c) from the adhesive layer (1) to the liquid crystal retardation film, and the change in the phase difference value can be substantially suppressed. The aromatic ring-containing (meth) acrylate (c) can also function as a high refractive index agent in the adhesive layer (1). This facilitates the in-plane average refractive index of the adhesive layer (1) and the in-plane average refractive index of a liquid crystal retardation film or the like adjacent to the adhesive layer (1) to be more similar, and can expect an effect of suppressing the interface reflection between these layers.

The number of aromatic rings contained in the aromatic ring-containing (meth) acrylate (c) is preferably 2 to 5, more preferably 2 to 3, and still more preferably 2 in the molecule. If the number of aromatic rings contained in the aromatic ring-containing (meth) acrylate (c) is within the above range, the durability of the resulting optical laminate can be further improved. The number of (meth) acryloyl groups in the aromatic ring-containing (meth) acrylate (c) may be, for example, 1 to 3, preferably 1 to 2, and in a preferred embodiment of the present invention, 1.

The refractive index of the aromatic ring-containing (meth) acrylate (c) is preferably 1.50 to 1.65, more preferably 1.55 to 1.60, and still more preferably 1.57 to 1.59. When the refractive index of the aromatic ring-containing (meth) acrylate (c) is within the above range, the function as a high refractive index agent can be sufficiently obtained, and an effect of suppressing an increase in the reflectance of the optical laminate can be expected.

Examples of the aromatic ring-containing (meth) acrylate (c) include ethoxylated o-phenylphenol acrylate, bisphenol a epoxy (meth) acrylate, bisphenol F epoxy (meth) acrylate, 2- ([ 1,1 '-biphenyl ] -2-yloxy) ethyl acrylate, 3-phenoxybenzyl acrylate, naphthalen-1-ylmethyl acrylate, 2- (2- ([ 1,1' -biphenyl ] -2-yloxy) ethoxy) ethyl acrylate, methyl (naphthalen-1-ylmethoxy) acrylate, 6 '-cyano- [1,1' -biphenyl ] -4-yloxy) hexyl acrylate, 4-benzoylphenyl acrylate, anthracene-9-ylmethyl acrylate, [1,1 '-biphenyl ] -4,4' -diyl diacrylate, 2- ((4 '-hydroxy- [1,1' -biphenyl ] -2-yl) oxy) ethyl acrylate, and the like. Among them, ethoxylated ortho-phenylphenol acrylates are preferable. The number of these may be 1 alone, or 2 or more may be used in combination.

The content of the aromatic ring-containing (meth) acrylate (c) in the adhesive composition (1) is preferably 10 to 60 parts by mass, more preferably 20 to 55 parts by mass, and even more preferably 25 to 50 parts by mass, relative to 100 parts by mass of the total amount of the curable compounds contained in the adhesive composition (1). If the content of the aromatic ring-containing (meth) acrylate (c) is within the above range, the decrease in the retardation value in the liquid crystal retardation film can be suppressed, and the effect of suppressing the increase in reflectance and the effect of improving adhesion can be expected. On the other hand, when the content of the aromatic ring-containing (meth) acrylate (c) is too large, the adhesion tends to be lowered and the phase difference tends to be lowered. When the aromatic ring-containing (meth) acrylate (c) is contained in an amount of 2 or more, the total content thereof is preferably within the above range.

In one embodiment of the present invention, the adhesive composition (1) preferably contains the curable compounds a) to c) in the amounts within the ranges described above.

In one embodiment of the present invention, the mass ratio of the urethane (meth) acrylate (a) to the hydroxyl group-containing (meth) acrylate (b) (urethane (meth) acrylate (a)/hydroxyl group-containing (meth) acrylate (b)) in the adhesive composition (1) is preferably 0.05 to 1.0, more preferably 0.1 to 0.9, and still more preferably 0.1 to 0.8. When the mass ratio of the urethane (meth) acrylate (a) to the hydroxyl group-containing (meth) acrylate (b) is in the above range, good coatability can be obtained, and the adhesion of the obtained adhesive layer can be easily improved.

In one embodiment of the present invention, the mass ratio of the urethane (meth) acrylate (a) to the aromatic ring-containing (meth) acrylate (c) (urethane (meth) acrylate (a)/aromatic ring-containing (meth) acrylate (c)) in the adhesive composition (1) is preferably 0.05 to 1.2, more preferably 0.1 to 1.0, and may be, for example, 0.5 to 1.0. If the mass ratio of the urethane (meth) acrylate (a) to the aromatic ring-containing (meth) acrylate (c) falls within the above range, the effect of suppressing the decrease in the retardation value of the liquid crystal retardation film is excellent, and a higher effect of suppressing the increase in reflectance and an effect of improving the adhesion can be expected.

In one embodiment of the present invention, the mass ratio of the hydroxyl group-containing (meth) acrylate (b) to the aromatic ring-containing (meth) acrylate (c) (hydroxyl group-containing (meth) acrylate (b)/aromatic ring-containing (meth) acrylate (c)) in the adhesive composition (1) is preferably 0.5 to 2.0, more preferably 0.6 to 1.8, and even more preferably 0.6 to 1.7. When the mass ratio of the hydroxyl group-containing (meth) acrylate (b) to the aromatic ring-containing (meth) acrylate (c) is in the above range, good coatability can be obtained, and an effect of suppressing decrease in the retardation value of the liquid crystal retardation film and an effect of improving the adhesion can be easily obtained.

In one embodiment of the present invention, the adhesive composition (1) preferably further comprises d) a (meth) acrylate having at least 1 aromatic ring and at least 1 hydroxyl group in the molecule (hereinafter, also referred to as "hydroxyl-and aromatic ring-containing (meth) acrylate (d)"). The hydroxyl group-and aromatic ring-containing (meth) acrylate (d) preferably functions as a refractive index adjuster in the adhesive layer (1). The number of hydroxyl groups in the (meth) acrylate (d) containing hydroxyl groups and aromatic rings is usually 1 to 3, preferably 1 to 2, more preferably 1. The number of aromatic rings is 1 to 3, preferably 1 to 2, more preferably 1. By using a (meth) acrylate having a hydroxyl group and an aromatic ring in good balance, the refractive index of the obtained adhesive layer (1) can be easily controlled, and the effect of suppressing interfacial reflection between layers is excellent. The number of (meth) acryloyl groups in the (meth) acrylate (d) having a hydroxyl group and an aromatic ring may be, for example, 1 to 6, preferably 1 to 2, and in a preferred embodiment of the present invention, 1. The number of aromatic rings in the (meth) acrylate (d) containing a hydroxyl group and an aromatic ring may be, for example, 1 to 2, and in a preferred embodiment of the present invention, 1.

The (meth) acrylate (d) having a hydroxyl group and an aromatic ring is not particularly limited, and may be selected from known (meth) acrylate compounds having a hydroxyl group and an aromatic ring. Specifically, for example, 4-hydroxyphenyl acrylate, 3-hydroxyphenyl acrylate, 2-hydroxy-3-phenoxypropyl acrylate, 2-hydroxy-4-phenoxybutyl acrylate, 2-hydroxy-5-phenoxypentyl acrylate, 3-hydroxy-4-phenoxybutyl acrylate, 4-hydroxy-5-phenoxypentyl acrylate, 2-hydroxy-3- (p-tolyloxy) propyl acrylate, 2-hydroxy-3- (m-tolyloxy) propyl acrylate, 2-hydroxy-3- (o-tolyloxy) propyl acrylate, 3-hydroxy-2-phenylpropyl acrylate, 4-hydroxy-2-phenylbutyl acrylate, 4-hydroxy-3-phenylbutyl acrylate and the like can be mentioned. The number of these may be 1 alone, or 2 or more may be used in combination. The (meth) acrylate (d) having a hydroxyl group and an aromatic ring may be commercially available.

The refractive index of the (meth) acrylate (d) containing a hydroxyl group and an aromatic ring is preferably 1.50 to 1.65, more preferably 1.50 to 1.60, and still more preferably 1.52 to 1.59. When the refractive index of the (meth) acrylate (d) containing a hydroxyl group and an aromatic ring is within the above range, the function as a refractive index adjuster is easily exhibited sufficiently, and an effect of suppressing the increase in the reflectance of the optical laminate can be expected.

When the adhesive composition (1) contains a (meth) acrylate (d) containing a hydroxyl group and an aromatic ring, the content thereof is preferably 3 to 40 parts by mass, more preferably 5 to 35 parts by mass, and even more preferably 10 to 30 parts by mass, relative to 100 parts by mass of the total amount of the curable compounds contained in the adhesive composition (1). When the content of the (meth) acrylate (d) containing a hydroxyl group and an aromatic ring is within the above range, an effect of suppressing the increase in reflectance and an effect of improving adhesion can be expected. In addition, the viscosity of the adhesive composition (1) can be easily adjusted, and good coatability can be imparted to the adhesive composition (1). When the (meth) acrylate (d) containing 2 or more hydroxyl groups and aromatic rings is contained, the total content thereof is preferably within the above range.

In one embodiment of the present invention, when the adhesive composition (1) contains the (meth) acrylate (d) having a hydroxyl group and an aromatic ring, the mass ratio of the urethane (meth) acrylate (a) to the (meth) acrylate (d) having a hydroxyl group and an aromatic ring (urethane (meth) acrylate (a)/the (meth) acrylate (d) having a hydroxyl group and an aromatic ring) is preferably 0.2 to 1.0, more preferably 0.3 to 1.0, and still more preferably 0.5 to 0.9. If the mass ratio of the urethane (meth) acrylate (a) to the (meth) acrylate (d) containing a hydroxyl group and an aromatic ring is within the above range, a reflectance increase suppressing effect and an adhesion improving effect can be expected, and good coatability can be obtained.

In one embodiment of the present invention, when the adhesive composition (1) contains the hydroxyl group-and aromatic ring-containing (meth) acrylate (d), the mass ratio of the hydroxyl group-containing (meth) acrylate (b) to the hydroxyl group-and aromatic ring-containing (meth) acrylate (d) (hydroxyl group-containing (meth) acrylate (b)/hydroxyl group-and aromatic ring-containing (meth) acrylate (d)) is preferably 0.5 to 4.0, more preferably 1.0 to 3.5. When the mass ratio of the hydroxyl group-containing (meth) acrylate (b) to the hydroxyl group-and aromatic ring-containing (meth) acrylate (d) is within the above range, the effect of suppressing the increase in reflectance and the effect of improving the adhesion can be expected, and good coatability can be obtained.

In one embodiment of the present invention, when the (meth) acrylate (d) containing a hydroxyl group and an aromatic ring is contained, the mass ratio of the (meth) acrylate (c) containing an aromatic ring to the (meth) acrylate (d) containing a hydroxyl group and an aromatic ring (aromatic ring-containing (meth) acrylate (c)/hydroxyl group-and aromatic ring-containing (meth) acrylate (d)) is preferably 0.5 to 6.0, more preferably 0.6 to 5.0. When the mass ratio of the aromatic ring-containing (meth) acrylate (c) to the hydroxyl group-and aromatic ring-containing (meth) acrylate (d) is within the above range, the effect of suppressing the decrease in the retardation value of the liquid crystal retardation film is excellent, and a higher effect of suppressing the increase in reflectance and an effect of improving the adhesion can be expected.

The adhesive composition (1) for forming the adhesive layer (1) adjacent to the liquid crystal retardation film may contain other curable compounds than the curable compounds a) to d). Examples of such other curable compounds include urethane (meth) acrylates having 3 or more (meth) acryloyl groups in the molecule, (meth) acrylates having 1 aromatic ring and no hydroxyl group in the molecule, and monofunctional or polyfunctional (meth) acrylates having no hydroxyl group and no aromatic ring in the molecule.

When the adhesive composition (1) contains other curable compounds than the curable compounds a) to d), the content thereof is preferably 10 parts by mass or less, more preferably 5 parts by mass or less, and the lower limit thereof is 0 parts by mass, relative to 100 parts by mass of the total amount of the curable compounds contained in the adhesive composition (1). If the content of the curable compounds other than the curable compounds a) to d) is within the above range, the effects of the present invention obtained by the curable compounds a) to c) and, if necessary, d) can be sufficiently ensured. When the curable compound contains 2 or more types of curable compounds other than the curable compounds a) to d), the total content thereof is within the above range. In a preferred embodiment of the present invention, the adhesive composition (1) does not contain any curable compound other than the curable compounds a) to d).

The adhesive composition (1) may contain a polymerization initiator. The polymerization initiator is a compound capable of initiating polymerization of curable compounds such as urethane (meth) acrylate (a), hydroxyl group-containing (meth) acrylate (b), aromatic ring-containing (meth) acrylate (c), hydroxyl group-containing and aromatic ring-containing (meth) acrylate (d). As the polymerization initiator, a photopolymerization initiator that generates a living radical by the action of light is preferable.

Examples of the polymerization initiator include benzoin compounds, benzophenone compounds, alkyl phenone compounds, acyl phosphine oxide compounds, triazine compounds, iodonium salts, sulfonium salts, and the like. As the polymerization initiator, only 1 kind may be used, or 2 or more kinds may be used in combination.

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

Examples of the benzophenone compound include benzophenone, methyl o-benzoyl benzoate, 4-phenylbenzophenone, 4-benzoyl-4 ' -methyldiphenyl sulfide, 3', 4' -tetrakis (t-butylperoxycarbonyl) benzophenone, and 2,4, 6-trimethylbenzophenone.

Examples of the alkylbenzene ketone compound include diethoxyacetophenone, 2-methyl-2-morpholino-1- (4-methylthiophenyl) propan-1-one, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) butan-1-one, 2-hydroxy-2-methyl-1-phenylpropane-1-one, 1, 2-diphenyl-2, 2-dimethoxyethane-1-one, 2-hydroxy-2-methyl-1- [4- (2-hydroxyethoxy) phenyl ] propan-1-one, 1-hydroxycyclohexylphenyl ketone, and oligomers of 2-hydroxy-2-methyl-1- [4- (1-methylvinyl) phenyl ] propan-1-one.

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

Examples of the triazine compound include 2, 4-bis (trichloromethyl) -6- (4-methoxyphenyl) -1,3, 5-triazine, 2, 4-bis (trichloromethyl) -6- (4-methoxynaphthyl) -1,3, 5-triazine, 2, 4-bis (trichloromethyl) -6- (4-methoxystyryl) -1,3, 5-triazine, 2, 4-bis (trichloromethyl) -6- [ 2- (5-methylfuran-2-yl) vinyl ] -1,3, 5-triazine, 2, 4-bis (trichloromethyl) -6- [ 2- (furan-2-yl) vinyl ] -1,3, 5-triazine, 2, 4-bis (trichloromethyl) -6- [ 2- (4-diethylamino-2-methylphenyl) vinyl ] -1,3, 5-triazine, and 2, 4-bis (trichloromethyl) -6- [ 2- (3, 4-dimethoxyphenyl) vinyl ] -1,3, 5-triazine.

As the polymerization initiator, commercially available ones can be used. Examples of commercially available polymerization initiators include, for example, irgacure 907, 184, 651, 819, 250 and 369 (available from Ciba SPECIALTY CHEMICALS, inc.), omnirad 819, omnirad 907, esacure 1001M, esacure KIP160 (available from IDM RESINS B.V. Inc.), parts of the seal (available from registered trademark) BZ, Z and BEE (available from Seiko Chemical Co., ltd.), parts of the order (kayacure) (available from registered trademark) BP100 and UVI-6992 (available from Dow Co., ltd.), adeka Optomer SP-152 and SP-170 (available from Dow Co., ltd.), TAZ-A and TAZ-PP (available from Nippon SiberHegner), and TAZ-104 (available from TAZ-SANWA CHEMICAL, etc.

In a preferred embodiment of the present invention, the molar absorption coefficient of the polymerization initiator used in the adhesive composition (1) at a light source wavelength of 400nm in acetonitrile solvent is preferably 10 L.mol ^-1·cm^-1 or more. A polymerization initiator having such a molar absorptivity can generally function as an initiator in the visible light region. Therefore, it is advantageous in the case where the adhesive composition is cured through a film that is impermeable to light in the ultraviolet light region. From the viewpoint of further improving the above effect, the molar absorption coefficient of the polymerization initiator at the light source wavelength of 400nm is more preferably 100l·mol ^-1·cm^-1 or more, preferably 500l·mol ^-1·cm^-1 or more, and more preferably 1000l·mol ^-1·cm^-1 or more. The molar absorptivity of the polymerization initiator at a light source wavelength of 400nm is usually 3000 L.mol ^-1·cm^-1 or less. The molar absorption coefficient of the polymerization initiator can be measured by, for example, adding a 0.001% solution obtained by dissolving the polymerization initiator in acetonitrile to a 1cm square quartz cuvette for measurement and using an ultraviolet-visible spectrophotometer (UV-2450, manufactured by Shimadzu corporation).

In the case where the adhesive composition (1) contains a polymerization initiator, the content thereof may be appropriately selected depending on the kind of the polymerizable compound and the amount thereof. From the viewpoint of initiator efficiency, the amount of the curable compound is preferably 0.5 to 10 parts by mass, more preferably 0.5 to 8 parts by mass, and even more preferably 0.5 to 5 parts by mass, based on 100 parts by mass of the total amount of the curable compound contained in the adhesive composition (1). If the content of the polymerization initiator is within the above range, the curable compound can be sufficiently cured.

The adhesive composition (1) may contain additives such as photosensitizers, leveling agents, antioxidants, stabilizers, flame retardants, viscosity modifiers, suds suppressors, antistatic agents, and the like, as required. When the adhesive composition (1) contains other additives, the content of the other additives is preferably more than 0% and 10% by mass or less, more preferably more than 0% and 5% by mass or less, relative to the solid content of the adhesive composition (1). In the present specification, the solid content of the adhesive composition means all components after volatile components such as an organic solvent are removed from the adhesive composition. Hereinafter, the term "solid component" as used herein refers to a component obtained by removing volatile components such as solvents from a composition to be treated.

In the present invention, the adhesive composition (1) may contain an organic solvent, for example, in order to adjust the viscosity to be suitable for the application method used, or may contain substantially no solvent (no solvent). "substantially free" means that the solvent is not inevitably mixed in. In one embodiment of the present invention, the adhesive composition (1) is free of solvent.

The viscosity of the adhesive composition (1) is preferably 500 mPas or less, more preferably 300 mPas or less, and even more preferably 250 mPas or less at 25 ℃. If the viscosity of the adhesive composition (1) is equal to or less than the upper limit value, the adhesive composition (1) has good fluidity, and therefore the adhesive composition (1) can be uniformly and thinly applied. The lower limit of the viscosity of the adhesive composition (1) at 25 ℃ is usually 5 mPas or more. The viscosity can be measured, for example, in accordance with JIS K7117-2.

The adhesive layer (1) can be formed, for example, by applying an adhesive composition (1) to the surface on which the adhesive layer (1) is formed, irradiating the coating film with active energy rays, and curing the adhesive composition (1). The method of applying and curing the adhesive composition (1) is not particularly limited, and may be appropriately selected from conventionally known methods for forming an active energy ray-curable adhesive layer.

As a method of applying the adhesive composition (1), for example, a known method such as a spin coating method, an extrusion method, a gravure coating method, a die coating method, a bar coating method, a coating method such as an applicator method, a printing method such as a flexographic method, or the like can be used.

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

The ultraviolet irradiation intensity is appropriately determined depending on the composition of the adhesive composition (1), and is not particularly limited, but is usually 10 to 3,000mW/cm ². The ultraviolet irradiation intensity is preferably an intensity in a wavelength region effective for activation of the polymerization initiator. The irradiation time of the light is usually 0.1 seconds to 10 minutes, preferably 1 second to 5 minutes, more preferably 5 seconds to 3 minutes, and still more preferably 10 seconds to 1 minute. If the ultraviolet irradiation intensity is applied 1 or more times, the cumulative light amount is 10 to 3,000mJ/cm ², preferably 50 to 2,000mJ/cm ², more preferably 100 to 1,000mJ/cm ².

The adhesive layer (1) formed from the adhesive composition (1) contains a structural unit derived from a urethane (meth) acrylate (a), a structural unit derived from a hydroxyl group-containing (meth) acrylate (b), and a structural unit derived from an aromatic ring-containing (meth) acrylate (c), and further preferably contains a structural unit derived from a hydroxyl group-containing (meth) acrylate (d) and an aromatic ring-containing (meth) acrylate in an amount or ratio corresponding to the amount of each curable compound blended in the adhesive composition (1), as the case may be.

The thickness of the adhesive layer (1) is not particularly limited, and may be appropriately determined depending on the composition and use of the optical laminate. For example, from the viewpoint of reducing the thickness of the optical laminate and securing adhesion, it is preferably 0.1 to 5 μm, more preferably 0.3 to 4 μm, and even more preferably 0.5 to 3 μm. The thickness of the adhesive layer (1) can be measured by a laser microscope, a film thickness meter, or the like. Hereinafter, the thickness of each layer such as a liquid crystal retardation film and a polarizing film constituting the optical laminate is also measured in the same manner.

< Liquid Crystal retardation film >

The optical laminate of the present invention comprises a liquid crystal retardation film adjacent to the adhesive layer (1). In the present invention, the liquid crystal retardation film preferably includes a liquid crystal cured film formed by aligning a polymerizable liquid crystal compound, and the liquid crystal cured film is composed of a single layer or includes a liquid crystal cured film and an alignment film for forming the liquid crystal cured film. The liquid crystal cured film constituting the liquid crystal retardation film (hereinafter, also referred to as "retardation liquid crystal cured film") may be formed from a composition containing a polymerizable liquid crystal compound (hereinafter, also referred to as "composition for forming a retardation film"). The liquid crystal retardation film including the liquid crystal cured film is preferable in terms of thickness reduction and capability of arbitrarily designing wavelength dispersion characteristics. On the other hand, the liquid crystal retardation film may undergo a decrease in the retardation value under high temperature conditions. In the optical laminate of the present invention, the liquid crystal retardation film is laminated adjacent to the adhesive layer (1) which is the cured product layer of the adhesive composition (1) containing the specific curable compound, whereby the effect of suppressing the change in the phase difference value due to the transfer of the aromatic ring-containing (meth) acrylate from the adhesive layer (1) is excellent. When the liquid crystal retardation film includes a retardation liquid crystal cured film and an alignment film, the layer located on the adhesive layer (1) side may be the retardation liquid crystal cured film or the alignment film. In one embodiment of the present invention, the orientation film is located on the adhesive layer (1) side.

The liquid crystal retardation film can be generally formed by applying a composition for forming a retardation film on an alignment film formed on a substrate, and polymerizing a polymerizable liquid crystal compound (hereinafter, also referred to as "polymerizable liquid crystal compound (1)") contained in the composition for forming a retardation film, and the cured film of a liquid crystal for retardation is generally a film obtained by curing the polymerizable liquid crystal compound (1) in an aligned state. In order to function the optical laminate of the present invention as a circularly polarizing plate, it is generally preferable that the liquid crystal retardation film comprises a "horizontally oriented liquid crystal cured film" in which a polymerizable liquid crystal compound is cured in a state of being oriented in a horizontal direction with respect to the plane of the retardation film. In this case, the polymerizable liquid crystal compound may be a positive a plate in the case of a rod-like liquid crystal, and may be a negative a plate in the case of a disk-like liquid crystal.

In the case where the liquid crystal retardation film has a λ/4 plate function (i.e., a pi/2 retardation function) in the entire visible light region, the antireflection function can be highly realized.

When the in-plane retardation for light having a wavelength of λnm is R (λ), the λ/4 plate function in the entire visible light region preferably satisfies the optical characteristics represented by the following formula (1), more preferably satisfies the optical characteristics represented by the following formulas (1), (2) and (3).

100nm<Re(550)<160nm (1)

(Wherein Re (550) represents the in-plane retardation value for light having a wavelength of 550 nm.)

Re(450)/Re(550)≤1.0 (2)

1.00≤Re(650)/Re(550) (3)

(Wherein Re (450) represents the in-plane phase difference value with respect to light having a wavelength of 450nm, re (550) represents the in-plane phase difference value with respect to light having a wavelength of 550nm, re (650) represents the in-plane phase difference value with respect to light having a wavelength of 650 nm.)

When the liquid crystal retardation film includes a retardation liquid crystal cured film and an alignment film, the in-plane retardation value of the liquid crystal retardation film is a value measured in a state where the two films are combined.

If the in-plane retardation value Re (550) of the liquid crystal retardation film is within the range of the formula (1), the retardation film functions as a lambda/4 wave plate, and the effect of improving the front reflection color tone (the effect of suppressing coloring) is improved when the circularly polarizing plate including the retardation film is applied to an organic EL display device or the like. In addition, if the liquid crystal phase difference film satisfies the above-described formulas (2) and (3), so-called inverse wavelength dispersion property is exhibited in which the in-plane phase difference value at a short wavelength is smaller than the in-plane phase difference value at a long wavelength. An optical laminate (circularly polarizing plate) having such a liquid crystal retardation film tends to have excellent light leakage suppressing effect on the short wavelength side and excellent front tone when assembled in an organic EL display device or the like. From the viewpoint of improving the inverse wavelength dispersion and further improving the effect of improving the reflection color in the front direction, re (450)/Re (550) is 0.7 or more and 1.0 or less, more preferably 0.80 or more and 0.95 or less, still more preferably 0.80 or more and 0.92 or less, and particularly preferably 0.82 or more and 0.88 or less. The ratio Re (650)/Re (550) is preferably 1.01 or more, more preferably 1.02 or more. These values can be arbitrarily controlled by adjusting the mixing ratio of the polymerizable liquid crystal compound, the lamination angle of the plurality of optically anisotropic layers, and the phase difference value.

The in-plane retardation value can be adjusted by the film thickness d of the retardation liquid crystal cured film. The in-plane retardation value is determined by the formula Re (λ) = (nx (λ) -ny (λ)) ×d [ in the formula, nx (λ) represents a principal refractive index at a wavelength λnm in the plane of the retardation liquid crystal cured film, ny (λ) represents a refractive index at a wavelength λnm in a direction orthogonal to the direction of nx in the same plane as nx, and d represents a film thickness of the retardation liquid crystal cured film ]. Therefore, the three-dimensional refractive index and the film thickness d may be adjusted to obtain a desired in-plane phase difference value (Re (λ): in-plane phase difference value of the retardation film at wavelength λ (nm)).

In the optical laminate of the present invention, the number of liquid crystal retardation films may be 1 or 2 or more. Specifically, it is preferable to include a liquid crystal retardation film having a λ/4 wave plate function, particularly a liquid crystal retardation film having a λ/4 wave plate function of inverse wavelength dispersion, or to combine at least 2 kinds of liquid crystal retardation films having different orientations. For example, a liquid crystal retardation film may be formed by combining a retardation film having a λ/2 plate function (i.e., a retardation function of pi) with a retardation film having a λ/4 plate function (i.e., a retardation function of pi/2). In addition, for example, a liquid crystal retardation film as a positive C plate (nx≡ny < nz) may be included in addition to the liquid crystal retardation film having a 1/4 wave plate function. The liquid crystal retardation film as the positive C plate is a "vertical alignment liquid crystal cured film" in which a polymerizable liquid crystal compound is cured in a state of being aligned in a vertical direction with respect to the retardation film plane. By combining a retardation film having a 1/4 wave plate function with a retardation film as a positive C plate, in the case of applying the optical laminate to an organic EL display device or the like, an improvement in the oblique reflection color tone can be expected in addition to an improvement in the front reflection color tone. The respective liquid crystal retardation films may be aligned obliquely or in a cholesteric alignment state.

When the optical laminate contains 2 or more liquid crystal cured films, at least 1 liquid crystal cured film is preferably present adjacent to the adhesive layer (1), more preferably a liquid crystal retardation film that is a horizontally oriented liquid crystal cured film is present adjacent to the adhesive layer (1), and even more preferably a liquid crystal retardation film having a λ/4 wave plate function is present adjacent to the adhesive layer (1). In addition, the liquid crystal retardation film closest to the polarizing film side is preferably present adjacent to the adhesive layer (1) on the polarizing film side. In these embodiments, the adhesive layer for bonding the liquid crystal retardation film other than the liquid crystal retardation film adjacent to the adhesive layer (1) to the other layer may be an adhesive layer formed of the adhesive composition (1), or may be an adhesive layer formed of an adhesive different from the adhesive composition or an adhesive layer formed of an adhesive.

In the present invention, the polymerizable liquid crystal compound (1) capable of forming a retardation film can be appropriately selected from conventionally known polymerizable liquid crystal compounds in the field of retardation plates according to desired optical characteristics. The polymerizable liquid crystal compound (1) usable in the present invention may be classified into a rod type (rod-like liquid crystal compound) and a discotic type (discotic liquid crystal compound ) depending on the shape thereof, for example, and any liquid crystal compound may be used. In addition, 2 or more rod-like liquid crystal compounds, 2 or more discotic liquid crystal compounds, or a mixture of rod-like liquid crystal compounds and discotic liquid crystal compounds may be used.

The polymerizable liquid crystal compound (1) is a liquid crystal compound having a polymerizable group. As the polymerizable liquid crystal compound (1), a polymer (cured product) obtained by polymerizing the polymerizable liquid crystal compound alone in a state of being oriented in a specific direction is generally exemplified by a polymerizable liquid crystal compound exhibiting positive wavelength dispersion and a polymerizable liquid crystal compound exhibiting inverse wavelength dispersion. In the present invention, either one of the polymerizable liquid crystal compounds may be used alone, or both of the polymerizable liquid crystal compounds may be used in combination. In addition, for example, in the case where the optical laminate includes a retardation film having a λ/4 plate function and a retardation film as a positive C plate, the polymerizable liquid crystal compounds constituting them may be the same or different from each other.

In the present invention, the polymerizable group of the polymerizable liquid crystal compound (1) forming the retardation film is preferably a photopolymerizable group. The photopolymerizable group means a group capable of participating in polymerization reaction by a reactive species generated by a photopolymerization initiator, for example, a reactive radical, an acid, or the like. Examples of the photopolymerizable group include vinyl, vinyloxy, 1-chlorovinyl, isopropenyl, 4-vinylphenyl, acryloyloxy, methacryloyloxy, oxiranyl, and oxetanyl groups. Among them, acryloyloxy, methacryloyloxy, ethyleneoxy, ethyleneoxide, and oxetanyl groups are preferable, and acryloyloxy is more preferable. The liquid crystal property may be a thermotropic liquid crystal or a lyotropic liquid crystal, and the thermotropic liquid crystal is preferable in view of being capable of controlling the film thickness in a compact state. The phase-ordered structure in the thermotropic liquid crystal may be a nematic liquid crystal or a smectic liquid crystal. As the polymerizable liquid crystal compound (1), only 1 kind may be used, or 2 or more kinds may be used in combination.

The polymerizable liquid crystal compound (1) is preferably a T-shaped or H-shaped polymerizable liquid crystal compound having a mesogenic structure, which is further birefringent in a direction perpendicular to the molecular long axis direction, from the viewpoint of exhibiting inverse wavelength dispersion, and is more preferably a T-shaped polymerizable liquid crystal compound from the viewpoint of obtaining stronger dispersion.

Specifically, examples of the polymerizable liquid crystal compound having a T-shaped liquid crystal structure include a compound represented by the following formula (X) (hereinafter, also referred to as "polymerizable liquid crystal compound (X)").

In the formula (X), ar represents a divalent aromatic group which may have a substituent. The divalent aromatic group preferably contains at least 1 or more of a nitrogen atom, an oxygen atom, and a sulfur atom. When the number of aromatic groups contained in the divalent group Ar is 2 or more, 2 or more aromatic groups may be bonded to each other through a divalent bonding group such as a single bond, -CO-O-, -O-.

G ¹ and G ² each independently represent a divalent aromatic group or a divalent alicyclic hydrocarbon group. The hydrogen atom contained in the divalent aromatic group or the divalent alicyclic hydrocarbon group may be substituted with a halogen atom, an alkyl group having 1 to 4 carbon atoms, a fluoroalkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a cyano group or a nitro group, and the carbon atoms 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、L²、B¹ and B ² are each independently a single bond or a divalent linking group.

K. l each independently represents an integer of 0 to 3 and satisfies a relationship of 1≤k+l. Here, in the case where 2≤k+l, B ¹ and B ²、G¹ and G ² may be the same or different from each other.

E ¹ and E ² each independently represent an alkanediyl group having 1 to 17 carbon atoms, wherein hydrogen atoms contained in the alkanediyl group may be substituted with halogen atoms, the-CH ₂ -contained in the alkanediyl group may be replaced by-O- -substitution of S-, -COO-, -S-, -a COO-substitution, the substitution being carried out. P ¹ and P ² each independently represent a polymerizable group or a hydrogen atom, and at least 1 is a polymerizable group.

Each of G ¹ and G ² is independently preferably a1, 4-phenylenediyl group which may be substituted with at least 1 substituent selected from a halogen atom and an alkyl group having 1 to 4 carbon atoms, a1, 4-cyclohexanediyl group which may be substituted with at least 1 substituent selected from a halogen atom and an alkyl group having 1 to 4 carbon atoms, more preferably a1, 4-phenylenediyl group substituted with a methyl group, an unsubstituted 1, 4-phenylenediyl group, or an unsubstituted 1, 4-trans-cyclohexanediyl group, particularly preferably an unsubstituted 1, 4-phenylenediyl group, or an unsubstituted 1, 4-trans-cyclohexanediyl group.

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

L ¹ and L ² are each independently preferably a single bond, an alkylene group 、－O－、－S－、－R^a1OR^a2－、－R^a3COOR^a4－、－R^a5OCOR^a6－、－R^a7OC＝OOR^a8－、－N＝N－、－CR^c＝CR^d－、 having 1 to 4 carbon atoms or-C.ident.C-. Here, R ^a1～R^a8 each independently represents a single bond or an alkylene group having 1 to 4 carbon atoms, and R ^c and R ^d each represent an alkyl group having 1 to 4 carbon atoms or a hydrogen atom. L ¹ and L ² are each independently more preferably a single bond, -OR ^a2-1－、－CH₂－、－CH₂CH₂－、－COOR^a4-1 -, OR-OCOR ^a6-1 -. Here, R ^a2-1、R^a4-1、R^a6-1 each independently represents any one of a single bond, -CH ₂－、－CH₂CH₂ -. L ¹ and L ² are each independently further preferably a single bond, -O-, -CH ₂CH₂－、－COO－、－COOCH₂CH₂ -, or-OCO-.

B ¹ and B ² are each independently preferably a single bond, an alkylene group having 1 to 4 carbon atoms, a-O-, -S-, -R ^a9OR^a10－、－R^a11COOR^a12－、－R^a13OCOR^a14 -, or-R ^a15OC＝OOR^a16 -. Here, R ^a9～R^a16 each independently represents a single bond or an alkylene group having 1 to 4 carbon atoms. More preferably, each of B ¹ and B ² is independently a single bond, -OR ^a10-1－、－CH₂－、－CH₂CH₂－、－COOR^a12-1 -, OR-OCOR ^a14-1 -. Here, R ^a10-1、R^a12-1、R^a14-1 each independently represents any one of a single bond, -CH ₂－、－CH₂CH₂ -. B ¹ and B ² are each independently further preferably a single bond, -O-, -CH ₂CH₂－、－COO－、－COOCH₂CH₂ -, -OCO-, or-OCOCH ₂CH₂ -.

From the viewpoint of exhibiting inverse wavelength dispersion, k and l are preferably in the range of 2≤k+l≤6, preferably k+l=4, more preferably k=2 and l=2. K=2 and l=2 are preferable because they have a symmetrical structure.

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

Examples of the polymerizable group represented by P ¹ or P ² include an epoxy group, a vinyl group, an ethyleneoxy group, a 1-chlorovinyl group, an isopropenyl group, a 4-vinylphenyl group, an acryloyloxy group, a methacryloyloxy group, an ethyleneoxy group, and an oxetanyl group. Among them, acryloyloxy, methacryloyloxy, ethyleneoxy, ethyleneoxide, and oxetanyl groups are preferable, and acryloyloxy is more preferable.

Ar preferably has at least one selected from the group consisting of an aromatic hydrocarbon ring which may have a substituent, an aromatic heterocyclic ring which may have a substituent, and an electron withdrawing group. Examples of the aromatic hydrocarbon ring include benzene ring, naphthalene ring, and anthracene ring, and benzene ring and naphthalene ring are preferable. Examples of the aromatic heterocycle include a furan ring, a benzofuran ring, a pyrrole ring, an indole ring, a thiophene ring, a benzothiophene ring, a pyridine ring, a pyrazine ring, a pyrimidine ring, a triazole ring, a triazine ring, a pyrroline ring, an imidazole ring, a pyrazole ring, a thiazole ring, a benzothiazole ring, a thienothiazole ring, an oxazole ring, a benzoxazole ring, and a phenanthroline ring. Among them, a thiazole ring, a benzothiazole ring, or a benzofuran ring is preferable, and a benzothiazolyl group is more preferable. In addition, in the case where a nitrogen atom is contained in Ar, the nitrogen atom preferably has pi electrons.

In the formula (X), the total number N _π of pi electrons contained in the 2-valent aromatic group represented by Ar is preferably 8 or more, more preferably 10 or more, still more preferably 14 or more, and particularly preferably 16 or more. The content is preferably 30 or less, more preferably 26 or less, and even more preferably 24 or less.

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

In the formulae (Ar-1) to (Ar-23),The label represents a linking part, and Z ⁰、Z¹ and Z ² each independently represent a hydrogen atom, a halogen atom, an alkyl group having 1 to 12 carbon atoms, a cyano group, a nitro group, an alkylsulfinyl group having 1 to 12 carbon atoms, an alkylsulfonyl group having 1 to 12 carbon atoms, a carboxyl group, a fluoroalkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an alkylthio group having 1 to 12 carbon atoms, an N-alkylamino group having 1 to 12 carbon atoms, an N, N-dialkylamino group having 2 to 12 carbon atoms, an N-alkylsulfonyl group having 1 to 12 carbon atoms, or an N, N-dialkylsulfamoyl group having 2 to 12 carbon atoms.

Q ¹ and Q ² each independently represent-CR ^2'R^3'－、－S－、－NH－、－NR^2' -; -CO-or-O-, R ^2' and R ^3' each independently represent 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 and Y ² each independently represent an aromatic hydrocarbon group or an aromatic heterocyclic group which may be substituted.

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 0to 6.

Examples of the aromatic hydrocarbon group in Y ¹ and Y ² include aromatic hydrocarbon groups having 6 to 20 carbon atoms such as phenyl, naphthyl, anthryl, phenanthryl, and biphenyl, and preferably phenyl and naphthyl, and more preferably phenyl. Examples of the aromatic heterocyclic group include an aromatic heterocyclic group having 4 to 20 carbon atoms, which contains at least 1 heteroatom such as a nitrogen atom, an oxygen atom, and a sulfur atom, such as a furyl group, a pyrrolyl group, a thienyl group, a pyridyl group, a thiazolyl group, and a benzothiazolyl group, and a thienyl group, a pyridyl group, a thiazolyl group, and a benzothiazolyl group are preferable.

Y ¹ and Y ² each independently may be a polycyclic aromatic hydrocarbon group or a polycyclic aromatic heterocyclic group which may be substituted. Polycyclic aromatic hydrocarbon groups refer to fused polycyclic aromatic hydrocarbon groups or groups derived from an aromatic ring set. Polycyclic aromatic heterocyclic groups refer to fused polycyclic aromatic heterocyclic groups, or groups derived from an aromatic ring set.

Z ⁰、Z¹ 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, an alkoxy group having 1 to 12 carbon atoms, Z ⁰ is more preferably a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, a cyano group, 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.

Q ¹ and Q ² are preferably-NH-, -S-, -NR ^2'－、－O－,R^2' are preferably hydrogen atoms. Wherein, the particularly preferred are-S-; -O-, -NH-.

In the formulae (Ar-1) to (Ar-23), the formulae (Ar-6) and (Ar-7) are preferable from the viewpoint of stability of the molecule.

In the formulae (Ar-17) to (Ar-23), Y ¹ may form an aromatic heterocyclic group together with the nitrogen atom to which it is bonded and Z ⁰. Examples of the aromatic heterocyclic group include aromatic heterocyclic groups which may be contained in Ar and are described above, and examples of the aromatic heterocyclic group 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, and a pyrrolidine ring. The aromatic heterocyclic group may have a substituent. In addition, Y ¹ may be the above-described polycyclic aromatic hydrocarbon group or polycyclic aromatic heterocyclic group which may be substituted together with the nitrogen atom to which it is bonded and Z ⁰. Examples thereof include benzofuran rings, benzothiazole rings, and benzoxazole rings.

In one embodiment of the present invention, the polymerizable liquid crystal compound (X) is preferably a compound having a maximum absorption wavelength of 300 to 400 nm. If the maximum absorption wavelength is within the above range, it is advantageous in terms of stability of the composition for forming a retardation film, and the alignment property and uniformity of film thickness of the obtained cured film of the retardation liquid crystal can be improved. The maximum absorption wavelength of the polymerizable liquid crystal compound (X) can be measured in a solvent using an ultraviolet-visible spectrophotometer. The solvent is a solvent capable of dissolving the polymerizable liquid crystal compound (X), and examples thereof include chloroform.

The polymerizable liquid crystal compound (X) can be produced, for example, by the method described in japanese unexamined patent publication No. 2010-31223.

In the present invention, as the polymerizable liquid crystal compound (1) forming the liquid crystal retardation film, in addition to the polymerizable liquid crystal compound (X) or in addition to the polymerizable liquid crystal compound (X), for example, a polymerizable liquid crystal compound such as those described in JP-A2010-31223, JP-A2010-270108, JP-A2011-6360 and JP-A2011-207765, a so-called polymerizable liquid crystal compound exhibiting positive wavelength dispersion, a polymerizable liquid crystal compound (Y) described later, or the like can be used. These polymerizable liquid crystal compounds can be used in both horizontal alignment and vertical alignment.

The content of the polymerizable liquid crystal compound (1) in the composition for forming a retardation film can be appropriately determined according to the desired optical characteristics of the optical laminate, the kind of the polymerizable liquid crystal compound (1) used, and the like. The content of the polymerizable liquid crystal compound (1) in the composition for forming a retardation film is, for example, 70 to 99.5 parts by mass, preferably 80 to 99 parts by mass, more preferably 85 to 98 parts by mass, and even more preferably 90 to 95 parts by mass, per 100 parts by mass of the solid content of the composition for forming a retardation film. If the content of the polymerizable liquid crystal compound (1) is within the above range, it is advantageous from the viewpoint of the orientation of the obtained retardation liquid crystal cured film.

The composition for forming a retardation film may contain, for example, an additive such as a polymerization initiator, a solvent, and a leveling agent, in addition to the polymerizable liquid crystal compound. As the polymerization initiator, a photopolymerization initiator that generates a living radical or an acid by the action of light is preferable in that the polymerization reaction can be initiated under a lower temperature condition, and a photopolymerization initiator that generates a radical by the action of light is more preferable. The polymerization initiator may be used alone, or 2 or more kinds may be used in combination.

As the photopolymerization initiator, a known photopolymerization initiator may be used, and examples of the photopolymerization initiator that generates a living radical include the same photopolymerization initiator as the one described above as the photopolymerization initiator that can be used in the adhesive composition (1), and may be appropriately selected from the relationship with the polymerizable liquid crystal compound that forms the retardation film.

The content of the polymerization initiator is preferably 0.1 to 20 parts by mass, more preferably 0.1 to 15 parts by mass, still more preferably 0.5 to 10 parts by mass, and particularly preferably 0.5 to 8 parts by mass, based on 100 parts by mass of the polymerizable liquid crystal compound (1). If the content of the polymerization initiator is within the above range, the polymerization reaction can be performed without greatly disturbing the alignment of the polymerizable liquid crystal compound.

The solvent is preferably a solvent which is completely soluble and inactive to the polymerization reaction, as long as it is appropriately selected according to the solubility of the polymerizable liquid crystal compound or the like used.

Specific examples of the solvent include alcohol solvents such as methanol, ethanol, ethylene glycol, isopropanol, propylene glycol, ethylene glycol methyl ether, ethylene glycol butyl ether and propylene glycol monomethyl ether, ester solvents such as ethyl acetate, butyl acetate, ethylene glycol methyl ether acetate, γ -butyrolactone, propylene glycol methyl ether acetate and ethyl lactate, ketone solvents such as acetone, methyl ethyl ketone, cyclopentanone, cyclohexanone, 2-heptanone and methyl isobutyl ketone, aliphatic hydrocarbon solvents such as pentane, hexane and heptane, aromatic hydrocarbon solvents such as toluene and xylene, nitrile solvents such as acetonitrile, ether solvents such as tetrahydrofuran and dimethoxyethane, chlorine-containing solvents such as chloroform and chlorobenzene, amide solvents such as N, N-dimethylacetamide and N, N-dimethylformamide, sulfur-containing solvents such as dimethylsulfone, dimethylsulfoxide and sulfolane, carbonate solvents such as ethylene carbonate and propylene carbonate, pyrrolidone solvents such as N-methylpyrrolidone, and the like. These solvents may be used alone or in combination of 2 or more.

The content of the solvent is preferably 100 to 1900 parts by mass, more preferably 150 to 1000 parts by mass, and even more preferably 180 to 800 parts by mass, based on 100 parts by mass of the solid content of the composition for forming a retardation film.

The composition for forming a retardation film may contain a leveling agent. The leveling agent has a function of adjusting the fluidity of the composition for forming a retardation film and flattening a coating film obtained by coating the composition. Specifically, a surfactant is exemplified. The leveling agent is preferably at least 1 kind selected from the group consisting of a leveling agent containing a polyacrylate compound as a main component and a leveling agent containing a fluorine atom-containing compound as a main component. The leveling agent may be used alone or in combination of 2 or more.

As leveling agents containing polyacrylate compounds as a main component, BYK-350, BYK-352, BYK-353, BYK-354, BYK-355, BYK-358N, BYK-361, N, BYK-380, BYK-381 and BYK-392 (BYK Chemie Co.).

As leveling agents containing fluorine atom-containing compounds as the main component, there may be mentioned, for example, megaface (registered trademark) R-08, R-30, R-90, F-410, F-411, F-443, F-445, F-470, F-471, F-477, F-479, F-482, F-483 and F-556 (DIC Co., ltd.); surflon (registered trademark) S-381, S-382, S-383, S-393, SC-101, SC-105, KH-40 and SA-100（AGC Seimi Chemical Co., Ltd.）;E1830、E5844（Daikin Fine Chemical Research Institute Ltd.）;Eftop EF301、Eftop EF303、Eftop EF351 and Eftop EF (Mitsubishi Materials Electronic Chemical Co., ltd.).

When the composition for forming a retardation film contains a leveling agent, the content thereof is preferably 0.01 to 5 parts by mass, more preferably 0.05 to 3 parts by mass, relative to 100 parts by mass of the polymerizable liquid crystal compound (1). If the content of the leveling agent is within the above range, the polymerizable liquid crystal compound (1) tends to be easily aligned, unevenness is less likely to occur, and a smoother retardation film tends to be obtained.

The composition for forming a retardation film may contain an additive other than the leveling agent. Examples of the other additives include colorants such as ionic compounds, polymerizable non-liquid crystal compounds, photosensitizers, antioxidants, mold release agents, stabilizers, bluing agents, flame retardants, lubricants, and the like. When the other additive is contained, the content of the other additive is preferably more than 0% and 20% by mass or less, more preferably more than 0% and 10% by mass or less, relative to the solid content of the composition for forming a polarizing film.

The composition for forming a retardation film can be produced by a conventionally known method for producing a liquid crystal composition, and is usually produced by mixing and stirring the polymerizable liquid crystal compound (1) with a polymerization initiator, a solvent, the above-mentioned additives, and the like as necessary.

The thickness of the liquid crystal retardation film may be appropriately selected according to the display device to be used. In one embodiment of the present invention, the thickness of the liquid crystal retardation film is preferably 0.5 μm to 5 μm, more preferably 1 μm to 3 μm. In the case where the liquid crystal retardation film includes a cured retardation liquid crystal film and an alignment film, the thickness of the liquid crystal retardation film is only the thickness of the cured retardation liquid crystal film.

In the present invention, a retardation liquid crystal cured film may be formed on an alignment film. The alignment film used for forming the cured film of the phase difference liquid crystal has an alignment regulating force for aligning the liquid crystal of the polymerizable liquid crystal compound (1) in a desired direction, and by applying the composition for forming the phase difference film on the alignment film, the cured film of the phase difference liquid crystal can be easily aligned with good precision. The alignment film is preferably one having solvent resistance that does not dissolve due to application or the like of the composition for forming a retardation film and heat resistance that is used in a heat treatment for removing a solvent and aligning a polymerizable liquid crystal compound.

Examples of the orientation film include an orientation film containing an orientation polymer, a photo-orientation film, a groove orientation film having a concave-convex pattern on the surface and a plurality of grooves, a stretched film stretched in the orientation direction, and the like. These various alignment films can be appropriately selected from those conventionally known in the art according to a desired alignment regulating force.

In one embodiment of the present invention, the liquid crystal retardation film preferably includes a photo-alignment film, that is, a liquid crystal cured film is formed on the photo-alignment film, from the viewpoint of easy improvement of alignment accuracy, adhesion to a liquid crystal cured film of a phase difference formed from a composition for forming a phase difference film, and the like. 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 irradiated polarized light.

The photo-alignment film is generally obtained by applying a composition containing a polymer, oligomer, or monomer having a photoreactive group and a solvent (hereinafter, also referred to as a "composition for forming a photo-alignment film") onto a substrate or the like, and irradiating polarized light (preferably polarized light UV). The photoreactive group refers to a group that generates liquid crystal aligning ability by irradiation with light. Specifically, a group involved in a photoreaction that causes the liquid crystal aligning ability, such as an alignment induction or isomerization reaction, dimerization reaction, photocrosslinking reaction, or photodecomposition reaction of a molecule generated by light irradiation, is exemplified. Among them, a group participating in dimerization reaction or photocrosslinking reaction is preferable in view of excellent orientation. As the photoreactive group, a group having an unsaturated bond, particularly a double bond, is preferable, and a group having at least 1 selected from a carbon-carbon double bond (c=c bond), a carbon-nitrogen double bond (c=n bond), a nitrogen-nitrogen double bond (n=n bond), and a carbon-oxygen double bond (c=o bond) is particularly preferable.

Specific examples of such an alignment film include a photo-alignment film as described in JP 2021-196514A, international publication No. 2018/003416, and the like.

The thickness of the alignment film is usually 10 to 5000nm, preferably 10 to 1000nm, more preferably 10 to 500nm, still more preferably 10 to 300nm, particularly preferably 30 to 300nm. When the thickness of the alignment film is in the above range, good adhesion can be exhibited at the interface with the cured product layer formed of the polymerizable liquid crystal compound (1) formed on the alignment film, and the alignment regulating force can be exerted, so that the liquid crystal retardation film can be formed with high alignment order.

The liquid crystal retardation film can be produced, for example, by a method comprising the steps of:

A step of forming a coating film of the composition for forming a retardation film;

a step of removing the solvent from the coating film;

a step of heating to a temperature not lower than the temperature at which the phase of the polymerizable liquid crystal compound (1) is converted into a liquid phase and then cooling to convert the phase of the polymerizable liquid crystal compound (1) into a liquid crystal phase, and

And polymerizing the polymerizable liquid crystal compound (1) while maintaining the liquid crystal phase.

The formation of the coating film of the composition for forming a retardation film may be performed by, for example, applying the composition on a substrate, an alignment film, or the like. The substrate may be a layer constituting the optical laminate of the present invention, but in one embodiment of the present invention, it is preferably a layer that is finally peeled off. As the substrate, a resin film substrate or the like conventionally known in the field of optical films can be used. Examples of the resin constituting such a resin film include polyolefin resins such as polyethylene and polypropylene, cycloolefin resins such as norbornene polymers, polyester resins such as polyethylene terephthalate and polyethylene naphthalate, poly (meth) acrylic resins such as (meth) acrylic acid and polymethyl (meth) acrylate, cellulose ester resins such as triacetyl cellulose, diacetyl cellulose and cellulose acetate propionate, vinyl alcohol resins such as polyvinyl alcohol and polyvinyl acetate, polycarbonate resins, polystyrene resins, polyarylate resins, polysulfone resins, polyethersulfone resins, polyamide resins, polyimide resins, polyether ketone resins, polyphenylene sulfide resins, polyphenylene ether resins, and mixtures thereof. These may be used alone or in combination of 2 or more. Such a resin can be formed into a resin film base material by a known method such as a solvent casting method or a melt extrusion method. Further, as the film base material or the resin constituting the film base material, commercially available products can be used.

The film substrate may be subjected to surface treatment such as corona treatment and plasma treatment, and release treatment in the case of peeling the substrate thereafter. The thickness of the base material is not particularly limited, and may be appropriately selected within a practical range. For example, the thickness may be about 5 to 300. Mu.m.

The method of coating the phase difference film-forming composition is not particularly limited, and the same method as that exemplified above as the method of coating the adhesive composition (1) can be used.

When the composition for forming a retardation film contains a solvent, the solvent is usually removed from the composition to be coated. Examples of the method for removing the solvent include a natural drying method, a ventilation drying method, a heat drying method, and a reduced pressure drying method. The dried film is preferably dried so that the residual solvent in the liquid crystal retardation film is 1 wt% or less relative to the total mass of the retardation film. The amount of the residual solvent can be determined by peeling and weighing a liquid crystal retardation film from a substrate or the like, immersing the retardation film in a solvent for dissolving the retardation film such as tetrahydrofuran, irradiating the solution with ultrasonic waves for about 10 minutes to extract a dissolved component, and analyzing the solution by gas chromatography. The conditions such as the drying temperature and the drying time can be appropriately determined depending on the composition of the composition for forming a retardation film, the material of the base material and the alignment film, and the like.

The polymerizable liquid crystal compound (1) in the coating film is usually heated to a temperature equal to or higher than a temperature at which the compound turns into a liquid crystal state or a solution state, and then cooled to a temperature at which liquid crystal alignment is performed to perform alignment, thereby forming a liquid crystal phase. The temperature at which the polymerizable liquid crystal compound (1) in the coating film is aligned may be determined in advance by texture observation (solar observation) or the like using a composition containing the polymerizable liquid crystal compound (1). In addition, the removal of the solvent and the alignment of the liquid crystal may be performed simultaneously. The temperature at this time is also dependent on the solvent to be removed and the type of polymerizable liquid crystal compound to be used, but is preferably in the range of 50 to 200 ℃, more preferably in the range of 80 to 130 ℃.

The polymerizable liquid crystal compound (1) is polymerized and cured while maintaining the liquid crystal state of the polymerizable liquid crystal compound (1), whereby a retardation liquid crystal cured film is formed as a cured product layer of the liquid crystal composition. As the polymerization method, photopolymerization is preferable. In photopolymerization, the light to be irradiated to the dry film is appropriately selected depending on the type of the polymerizable liquid crystal compound or the like (particularly the type of the polymerizable group of the polymerizable liquid crystal compound), the type of the polymerization initiator, the amount thereof, and the like contained in the dry film.

The conditions such as the light source of the active energy ray and the ultraviolet irradiation intensity are appropriately determined according to the composition of the composition for forming a retardation film, and are not particularly limited. For example, the same light source, irradiation conditions, and the like as those of the example described above in the method for producing the adhesive layer (1) can be used.

< Polarizing film >

The optical laminate of the present invention comprises a polarizing film. The polarizing film constituting the optical laminate of the present invention is a cured layer of a polymerizable liquid crystal composition (hereinafter also referred to as "composition for forming a polarizing film") containing a polymerizable liquid crystal compound and a dichroic dye. If the polarizing film is a cured layer of the composition for forming a polarizing film, high visibility can be imparted by using the polarizing film as a circular polarizing plate having an antireflection function in combination with a phase difference film for an organic EL display device. When the optical laminate of the present invention functions as a circularly polarizing plate, the polarizing film is generally a horizontal polarizing film in which a polymerizable liquid crystal compound and a dichroic dye are cured in a state of being oriented in a horizontal direction with respect to the plane of the polarizing film. Such a horizontal polarizing film generally has a function of transmitting light vibrating in the transmission axis direction but blocking polarized light of a vibrating component perpendicular thereto, and functions as a polarizing film for extracting linearly polarized light from incident natural light.

The polymerizable liquid crystal compound (hereinafter also referred to as "polymerizable liquid crystal compound (2)") contained in the composition for forming a polarizing film in the present invention is a compound having at least 1 polymerizable group and having liquid crystallinity. The polymerizable group is preferably a photopolymerizable group, and examples thereof are the same as those exemplified as the polymerizable groups included in the polymerizable liquid crystal compound (1) capable of forming a liquid crystal retardation film. Among them, acryloyloxy, methacryloyloxy, ethyleneoxy, ethyleneoxide, and oxetanyl groups are more preferable, and acryloyloxy or methacryloyloxy is further preferable.

In the present invention, the polymerizable liquid crystal compound (2) forming the polarizing film is preferably a liquid crystal compound exhibiting a smectic liquid crystal phase. By using a polymerizable liquid crystal compound exhibiting a smectic liquid crystal phase, a polarizing film having a high alignment order and excellent polarizing function can be formed. From the viewpoint of enabling higher alignment order, the liquid crystal state exhibited by the polymerizable liquid crystal compound is more preferably a higher order smectic phase (higher order smectic liquid crystal state). The higher order smectic phase herein means smectic B phase, smectic D phase, smectic E phase, smectic F phase, smectic G phase, smectic H phase, smectic I phase, smectic J phase, smectic K phase and smectic L phase, and among these, smectic B phase, smectic F phase and smectic I phase are more preferable. The liquid crystal property may be a thermotropic liquid crystal or a lyotropic liquid crystal, and the thermotropic liquid crystal is preferable in view of being capable of controlling the film thickness in a compact state. The polymerizable liquid crystal compound may be a monomer, an oligomer obtained by polymerizing polymerizable groups, or a polymer.

Examples of such a polymerizable liquid crystal compound include a compound represented by the formula (Y) (hereinafter, also referred to as "polymerizable liquid crystal compound (Y)").

U¹－V¹－W¹－（X¹－Y¹）_n－X²－W²－V²－U² （Y）

In the formula (Y), the amino acid sequence of the formula (Y),

X ¹ and X ² each independently represent a 2-valent aromatic group or a 2-valent alicyclic hydrocarbon group, wherein a hydrogen atom contained in the 2-valent aromatic group or the 2-valent alicyclic hydrocarbon group may be substituted with a substituent selected from the group consisting of a halogen atom, an alkyl group having 1 to 4 carbon atoms, a fluoroalkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a cyano group and a nitro group, and a carbon atom constituting the 2-valent aromatic group or the 2-valent alicyclic hydrocarbon group may be substituted with an oxygen atom, a sulfur atom or a nitrogen atom. Wherein at least 1 of X ¹ and X ² is the above-mentioned 1, 4-phenylene group which may have a substituent or the above-mentioned cyclohexane-1, 4-diyl group which may have a substituent.

Y ¹ is a single bond or a divalent linking group.

N is 1 to 3, and when n is 2 or more, a plurality of X ¹ may be the same or different from each other. X ² may be the same as or different from any or all of the plurality of X ¹. When n is 2 or more, the plural Y ¹ may be the same or different from each other. From the viewpoint of liquid crystal property, n is preferably 2 or more.

U ¹ represents a hydrogen atom or a polymerizable group.

U ² represents a polymerizable group.

W ¹ and W ² are each independently a single bond or a divalent linking group.

V ¹ and V ² each independently represent an alkanediyl group having 1 to 20 carbon atoms which may have a substituent, the alkanediyl radical-CH ₂ -may be replaced by-O-, -CO-, -S-, or-NH-substitution.

In the polymerizable liquid crystal compound (Y), X ¹ and X ² are each independently preferably a1, 4-phenylene group which may have a substituent, or a cyclohexane-1, 4-diyl group which may have a substituent, and at least 1 of X ¹ and X ² is a1, 4-phenylene group which may have a substituent, or a cyclohexane-1, 4-diyl group which may have a substituent, preferably a trans-cyclohexane-1, 4-diyl group. Examples of the substituent which may be optionally contained in the 1, 4-phenylene group which may have a substituent or the cyclohexane-1, 4-diyl group which may have a substituent include an alkyl group having 1 to 4 carbon atoms such as a methyl group, an ethyl group and a butyl group, a cyano group, a chlorine atom, a fluorine atom and other halogen atoms. Preferably unsubstituted.

In addition, from the viewpoint of easily exhibiting smectic liquid crystallinity, the polymerizable liquid crystal compound (Y) is preferably an asymmetric structure of the moiety [ hereinafter referred to as a partial structure (Y1) ] represented by the formula (Y1) in the formula (Y1):

-(X¹－Y¹）_n－X²- (Y1)

[ in the formula (Y1), X ¹、Y¹、X² and n each represent the same meaning as described above. A kind of electronic device.

Examples of the polymerizable liquid crystal compound (2) having an asymmetric partial structure (Y1) include polymerizable liquid crystal compounds (Y) having n of 1, 1X ¹ and X ² having different structures from each other.

Further, there may be mentioned a polymerizable liquid crystal compound (Y) in which n is 2, 2Y ¹ are the same structure as each other, 2X ¹ are the same structure as each other, and 1X ² is a structure different from those of 2X ¹;

Among 2X ¹, X ¹ bonded to W ¹ is a polymerizable liquid crystal compound (Y) having a structure different from that of the other X ¹ and X ² and the other X ¹ and X ² are the same structure as each other.

Further, a polymerizable liquid crystal compound (Y) in which n is 3, 3Y ¹ have the same structure as each other, and any 1 of 3X ¹ and 1X ² have a structure different from all the other 3 is also exemplified.

Y ¹ is preferably-CH ₂CH₂－、－CH₂O－、－CH₂CH₂ O-, -COO-, -OCOO-, a single bond, -n=n-, a-CR ^a＝CR^b－、－C≡C－、－CR^a =n-or-CO-NR ^a－.R^a and R ^b each independently represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. Y ¹ is more preferably-CH ₂CH₂ -, -COO-or a single bond, in the case where a plurality of Y ¹ are present, Y ¹ bonded to X ² is more preferably-CH ₂CH₂ -or-CH ₂ O-. When X ¹ and X ² are all the same structure, it is preferable that Y ¹ be present in 2 or more different bonding modes. If there are a plurality of Y ¹ that are different bonding modes, the structure becomes asymmetric, and thus there is a tendency that smectic liquid crystallinity is easily developed.

U ² is a polymerizable group. U ¹ is a hydrogen atom or a polymerizable group, preferably a polymerizable group. Preferably, both U ¹ and U ² are polymerizable groups, preferably both free radical polymerizable groups. Examples of the polymerizable group include the same groups as those exemplified above as the polymerizable groups of the polymerizable liquid crystal compound (2). The polymerizable group shown in U ¹ and the polymerizable group shown in U ² may be different from each other, but are preferably the same kind of groups. The polymerizable group may be in a polymerized state or an unpolymerized state, and is preferably in an unpolymerized state.

Examples of the alkanediyl group represented by V ¹ and V ² include methylene, ethylene, propane-1, 3-diyl, butane-1, 4-diyl, pentane-1, 5-diyl, hexane-1, 6-diyl, heptane-1, 7-diyl, octane-1, 8-diyl, decane-1, 10-diyl, tetradecane-1, 14-diyl and eicosane-1, 20-diyl. V ¹ and V ² are preferably alkanediyl groups having 2 to 12 carbon atoms, more preferably alkanediyl groups having 6 to 12 carbon atoms.

Examples of the substituent optionally contained in the alkanediyl group include a cyano group and a halogen atom, and the alkanediyl group is preferably unsubstituted, more preferably unsubstituted, linear alkanediyl group.

W ¹ and W ² are each independently of the other preferably a single bond, -O-, -S-, -COO-or-OCOO-, more preferably a single bond or-O-.

The structure that tends to exhibit smectic liquid crystallinity is preferably a molecular structure having asymmetry in the molecular structure, and specifically, if the structure is a polymerizable liquid crystal compound having the structure represented by the following formula (a-a) to formula (a-i), smectic liquid crystallinity tends to be exhibited, and is suitable as the polymerizable liquid crystal compound (Y). Further, from the viewpoint of easily exhibiting higher-order smectic liquid crystallinity, it is more preferable to have a structure represented by the formula (A-a), the formula (A-b) or the formula (A-c). In the following formulae (A-a) to (A-i), the bond (single bond) is represented by the following formula (A-a).

Specifically, the polymerizable liquid crystal compound (Y) is a compound represented by the formula (A-1) to the formula (A-25). When the polymerizable liquid crystal compound (Y) has a cyclohexane-1, 4-diyl group, the cyclohexane-1, 4-diyl group is preferably a trans-form.

Among them, at least 1 selected from the group consisting of the compounds represented by the formula (A-2), the formula (A-3), the formula (A-4), the formula (A-5), the formula (A-6), the formula (A-7), the formula (A-8), the formula (A-13), the formula (A-14), the formula (A-15), the formula (A-16) and the formula (A-17) is preferable. As the polymerizable liquid crystal compound (Y), 1 kind may be used alone, or 2 or more kinds may be used in combination.

The polymerizable liquid crystal compound (Y) can be produced by a known method described in Lub et al, recl.Trav.Chim.Pays-Bas,115,321-328 (1996), japanese patent No. 4719156, or the like.

The composition for forming a polarizing film may contain other polymerizable liquid crystal compounds than the polymerizable liquid crystal compound (Y) as long as the effect of the present invention is not impaired. From the viewpoint of obtaining a polarizing film having a high alignment order, the proportion of the polymerizable liquid crystal compound (Y) in the composition for forming a polarizing film to the total mass of all the polymerizable liquid crystal compounds (2) is preferably 51 mass% or more, more preferably 70 mass% or more, still more preferably 90 mass% or more, and the polymerizable liquid crystal compound may be the polymerizable liquid crystal compound (Y) in its entirety (100 mass%).

When the composition for forming a polarizing film contains 2 or more kinds of polymerizable liquid crystal compounds (2), at least 1 of them is preferably the polymerizable liquid crystal compound (Y), and all of the components contained in the composition for forming a polarizing film may be the polymerizable liquid crystal compound (Y).

The content of the polymerizable liquid crystal compound (2) in the composition for forming a polarizing film is preferably 40 to 99.9% by mass, more preferably 60 to 99.9% by mass, and even more preferably 70 to 99% by mass, based on the solid content of the composition for forming a polarizing film. If the content of the polymerizable liquid crystal compound is within the above range, the orientation of the polymerizable liquid crystal compound (2) tends to be high.

The composition for forming a polarizing film contains a dichroic dye. Here, the dichroic dye means a dye having a property that the absorbance in the long axis direction of the molecule is different from the absorbance in the short axis direction. The dichroic dye that can be used in the present invention is not particularly limited as long as it has the above properties, and may be a dye or a pigment. More than 2 kinds of dyes or pigments may be used in combination, respectively, or a combination of dyes and pigments may be used. The dichroic dye may be used alone or in combination, and in order to absorb the entire visible light, it is preferable to combine 2 or more dichroic dyes, and more preferably 3 or more dichroic dyes. In particular, by mixing 2 or more kinds of dichroic dyes having different absorption wavelengths, a polarizing film having various hues can be produced, and a polarizing film having absorption in the entire visible light region can be produced.

The dichroic dye preferably has a characteristic of absorbing visible light, and preferably has a maximum absorption wavelength (λ _MAX) in the range of 300 to 700 nm. Examples of such dichroic dyes include acridine dyes, oxazine dyes, cyanine dyes, naphthalene dyes, azo dyes, and anthraquinone dyes. Among them, azo pigments are preferable.

The azo dye includes monoazo dye, disazo dye, trisazo dye, tetrazo dye, stilbene azo dye, and the like, and preferably the disazo dye and trisazo dye include, for example, a compound represented by the formula (I) (hereinafter, also referred to as "compound (I)").

K¹（－N＝N－K²）_p－N＝N－K³ (I)

In the formula (I), K ¹ and K ³ each independently represent a phenyl group which may have a substituent, a naphthyl group which may have a substituent, a phenyl benzoate group which may have a substituent, or a 1-valent heterocyclic group which may have a substituent. K ² represents a p-phenylene group which may have a substituent, a naphthalene-1, 4-diyl group which may have a substituent, a 4,4' -styrylene group which may have a substituent, or a 2-valent heterocyclic group which may have a substituent. p represents an integer of 0 to 4. When p is an integer of 2 or more, a plurality of K ² may be the same or different from one another. In the range where absorption is shown in the visible region, -n=n-bonds may be replaced with-c=c-, -COO-, -NHCO-, -n=ch-bonds. ]

Examples of the 1-valent heterocyclic group include a group obtained by removing 1 hydrogen atom from a heterocyclic compound such as quinoline, thiazole, benzothiazole, thienothiazole, imidazole, benzimidazole, oxazole, and benzoxazole. Examples of the 2-valent heterocyclic group include a group obtained by removing 2 hydrogen atoms from the heterocyclic compound.

Examples of the substituent optionally contained in the phenyl group, naphthyl group, phenyl benzoate group and 1-valent heterocyclic group in K ¹ and K ³, and the p-phenylene group, naphthalene-1, 4-diyl group, 4' -styrylene group and 2-valent heterocyclic group in K ² include an alkyl group having 1 to 20 carbon atoms, an alkyl group having 1 to 20 carbon atoms having a polymerizable group, an alkenyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 20 carbon atoms such as methoxy group, ethoxy group and butoxy group, an alkoxy group having 1 to 20 carbon atoms having a polymerizable group, a fluoroalkyl group having 1 to 4 carbon atoms such as trifluoromethyl group, a cyano group, a nitro group, a halogen atom, an amino group, a diethylamino group, a pyrrolidinyl group and the like (a substituted amino group means an amino group having 1 to 2 alkyl groups having 1 to 6 carbon atoms, an amino group having 1 to 2 alkyl groups having 1 to 6 carbon atoms having a polymerizable group, or a di-substituted amino group having 2 alkyl groups having 2 to 8 carbon atoms bonded to each other to form an alkyl group having ₂ having 2 to 8 carbon atoms). Examples of the polymerizable group include a (meth) acryloyl group and a (meth) acryloyloxy group.

Among the compounds (I), preferred are compounds represented by any of the following formulas (I-1) to (I-8).

In the formulas (I-1) - (I-8),

B ¹～B³⁰ each independently represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a cyano group, a nitro group, a substituted or unsubstituted amino group (the substituted amino group and the unsubstituted amino group are defined as above), a chlorine atom or a trifluoromethyl group.

N1 to n4 independently represent an integer of 0 to 3.

When n1 is 2 or more, a plurality of B ² may be the same as or different from each other,

When n2 is 2 or more, a plurality of B ⁶ may be the same as or different from each other,

When n3 is 2 or more, a plurality of B ⁹ may be the same as or different from each other,

When n4 is 2 or more, a plurality of B ¹⁴ may be the same or different from each other. ]

As the anthraquinone pigment, a compound represented by the formula (I-9) is preferable.

In the formula (I-9),

R ¹～R⁸ each independently represents a hydrogen atom, -R ^x、－NH₂、－NHR^x、－NR^x ₂、－SR^x, or a halogen atom.

R ^x represents an alkyl group having 1 to 4 carbon atoms or an aryl group having 6 to 12 carbon atoms. ]

The oxazinone dye (azone dye) is preferably a compound represented by the formula (I-10).

In the formula (I-10),

R ⁹～R¹⁵ each independently represents a hydrogen atom, -R ^x、－NH₂、－NHR^x、－NR^x ₂、－SR^x, or a halogen atom.

R ^x represents an alkyl group having 1 to 4 carbon atoms or an aryl group having 6 to 12 carbon atoms. ]

As the acridine dye, a compound represented by the formula (I-11) is preferable.

In the formula (I-11),

R ¹⁶～R²³ each independently represents a hydrogen atom, -R ^x、－NH₂、－NHR^x、－NR^x ₂、－SR^x, or a halogen atom.

R ^x represents an alkyl group having 1 to 4 carbon atoms or an aryl group having 6 to 12 carbon atoms. ]

In the formulae (I-9), (I-10) and (I-11), the alkyl group having 1 to 6 carbon atoms of R ^x is exemplified by methyl, ethyl, propyl, butyl, pentyl and hexyl, and the aryl group having 6 to 12 carbon atoms is exemplified by phenyl, tolyl, xylyl and naphthyl.

As the cyanine dye, a compound represented by the formula (I-12) and a compound represented by the formula (I-13) are preferable.

In the formula (I-12),

D ¹ and D ² independently represent a group represented by any one of the formulae (I-12 a) to (I-12D).

N5 represents an integer of 1 to 3. ]

In the formula (I-13),

D ³ and D ⁴ independently represent a group represented by any one of the formulae (I-13 a) to (I-13 h).

N6 represents an integer of 1 to 3. ]

The weight average molecular weight of the dichroic dye is usually 300 to 2000, preferably 400 to 1000.

The content of the dichroic dye in the composition for forming a polarizing film may be appropriately determined depending on the type of the dichroic dye used, and is preferably 1 to 60% by mass, more preferably 1 to 20% by mass, and even more preferably 1 to 15% by mass, relative to the solid content of the composition for forming a polarizing film. If the content of the dichroic dye is within the above range, the alignment of the polymerizable liquid crystal compound is not easily disturbed, and a polarizing film having a high alignment order can be obtained.

The composition for forming a polarizing film may contain a polymerization initiator. As the polymerization initiator, a photopolymerization initiator that generates a living radical or an acid by the action of light is preferable, and a photopolymerization initiator that generates a radical by the action of light is more preferable, in view of being capable of initiating a polymerization reaction under a lower temperature condition. The polymerization initiator may be used alone, or 2 or more kinds may be used in combination.

As the photopolymerization initiator, a known photopolymerization initiator can be used. For example, the same photopolymerization initiator as that exemplified above as the photopolymerization initiator that can be used in the adhesive composition (1) may be appropriately selected from the relationship with the polymerizable liquid crystal compound (2) forming the polarizing film.

The content of the polymerization initiator is preferably 0.1 to 20 parts by mass, more preferably 0.1 to 15 parts by mass, still more preferably 0.5 to 10 parts by mass, and particularly preferably 0.5 to 8 parts by mass, based on 100 parts by mass of the polymerizable liquid crystal compound (2). If the content of the polymerization initiator is within the above range, the polymerization reaction can be performed without greatly disturbing the orientation of the polymerizable liquid crystal compound (2).

The composition for forming a polarizing film may contain a leveling agent, an additive exemplified as an additive contained in the composition for forming a retardation film, and the like as necessary. Examples of the leveling agent and additive include the same leveling agent and additive as those exemplified above as the leveling agent and additive that can be used in the composition for forming a polarizing film, and the leveling agent and additive can be used in amounts equivalent to the blending amounts in the composition for forming a polarizing film.

The composition for forming a polarizing film can be produced by a conventionally known method for producing a liquid crystal composition, and is usually produced by mixing and stirring a polymerizable liquid crystal compound and a dichroic dye, and if necessary, a polymerization initiator and the above-mentioned additives. In addition, since a liquid crystal compound exhibiting smectic liquid crystallinity generally has a high viscosity, the viscosity can be adjusted by adding a solvent to the composition from the viewpoint of improving the coatability of the liquid crystal composition and easily forming a polarizing film.

The solvent is preferably a solvent which is completely soluble and inactive to the polymerization reaction, as long as it is appropriately selected according to the solubility of the polymerizable liquid crystal compound, dichroic dye, and the like used. The solvent may be the same as the solvent used in the composition for forming a retardation film.

The thickness of the polarizing film may be appropriately selected according to the display device to be applied. In one embodiment of the present invention, the thickness of the polarizing film is preferably 0.1 to 5 μm, more preferably 0.5 to 3 μm.

In the present invention, the polarizing film is preferably a liquid crystal cured film having a high alignment order. The cured liquid crystal film having a high degree of orientation order can obtain Bragg peaks from higher order structures such as hexagonal phase and crystalline phase in X-ray diffraction measurement. The bragg peak refers to a peak from the surface periodic structure of the molecular orientation. Therefore, the polarizing film constituting the optical laminate of the present invention preferably exhibits a bragg peak in an X-ray diffraction measurement. That is, in the present invention, the polarizing film is preferably oriented to the polymerizable liquid crystal compound (2) or a polymer thereof so that the film shows a bragg peak in an X-ray diffraction measurement. In one embodiment of the present invention, the surface period spacing of the molecular orientation is preferably 3.0 to 6.0 a. The high degree of alignment order such as the bragg peak can be achieved by controlling the kind of the polymerizable liquid crystal compound used, the kind and amount of the dichroic dye, the kind and amount of the polymerization initiator, and the like.

The polarizing film may be formed on the orientation film in the present invention. As the alignment film, the same alignment film as the one described above as an example of the alignment film that can be used for producing the liquid crystal retardation film may be used, and may be appropriately selected according to a desired alignment regulating force or the like. In one embodiment of the present invention, the photo-alignment film is preferable from the viewpoint of easy improvement of alignment accuracy, adhesion to a cured layer formed from the composition for forming a polarizing film, and the like.

The thickness of the alignment film is usually 10 to 5000nm, preferably 10 to 1000nm, more preferably 10 to 500nm, still more preferably 10 to 300nm, particularly preferably 30 to 300nm. When the thickness of the alignment film is in the above range, good adhesion can be exhibited at the interface with the cured product layer formed from the composition for forming a polarizing film formed on the alignment film, and the alignment regulating force can be exerted, so that the polarizing film can be formed in a high alignment order.

The polarizing film can be manufactured, for example, by a method comprising the steps of:

a step of forming a coating film of the composition for forming a polarizing film;

a step of removing the solvent from the coating film;

A step of heating to a temperature not lower than the temperature at which the phase of the polymerizable liquid crystal compound (2) is converted into a liquid crystal phase and then cooling to convert the phase of the polymerizable liquid crystal compound (2) into a liquid crystal phase (e.g., smectic liquid crystal phase), and

And polymerizing the polymerizable liquid crystal compound (2) while maintaining the liquid crystal phase.

Examples of the method that can be used for the application of the composition for forming a polarizing film, the curing of the polymerizable liquid crystal compound by light irradiation, and the like include the same methods as those exemplified for the adhesive composition (1) and the method for forming a liquid crystal retardation film.

The optical laminate of the present invention comprises, in order, a polarizing film, an adhesive layer (1), and a liquid crystal cured film adjacent to the adhesive layer (1). The optical laminate of the present invention may further comprise other layers in addition to the polarizing film, the adhesive layer (1), and the liquid crystal retardation film adjacent to the adhesive layer (1), as long as the effects of the present invention are not impaired. Examples of the other layer include an alignment film for forming a polarizing film, a hard coat layer for protecting a polarizing film and/or a liquid crystal retardation film, and an adhesive layer other than the adhesive layer (1).

In one embodiment of the present invention, the optical laminate of the present invention preferably comprises a hard coat layer between the polarizing film and the adhesive layer (1). By including the hard coat layer, the polarizing film can be reinforced in strength. In another embodiment of the present invention, the optical laminate of the present invention preferably includes a polarizing film, an alignment film, a hard coat layer, an adhesive layer (1), and a liquid crystal retardation film in a manner that they are adjacent to each other in this order.

When the optical laminate of the present invention includes a hard coat layer between the polarizing film and the adhesive layer (1), the in-plane average refractive index of the hard coat layer (hereinafter, also simply referred to as "refractive index n 1"), the in-plane average refractive index of the liquid crystal phase difference film (hereinafter, also simply referred to as "refractive index n 2"), and the in-plane average refractive index of the adhesive layer (1) (hereinafter, also simply referred to as "refractive index n 3") preferably satisfy the following formulas:

|(n1×n2)^1/2-n3|≤0.018。

If the in-plane average refractive index of the three layers satisfies the above-described relationship, an effect of suppressing light reflection at the interface between adjacent two layers can be expected. Thus, when the obtained optical laminate is incorporated into a display device, light reflection of the taken-in external light between the layers can be effectively suppressed. In order to further enhance such effects, the value of (n1×n2) ^1/2 to n3 is more preferably 0.015 or less, still more preferably 0.013 or less, particularly preferably 0.010 or less, preferably 0.0001 or more, still more preferably 0.001 or more.

In the present invention, the in-plane average refractive index n3 of the adhesive layer (1) is preferably 1.50 to 1.60, more preferably 1.52 to 1.58, and even more preferably 1.54 to 1.56. If the in-plane average refractive index of the adhesive layer (1) is in the above range, light reflection at the interface of the hard coat layer and the adhesive layer (1) can be suppressed. In addition, light reflection at the interface between the adhesive layer (1) and the liquid crystal phase difference film is also easily suppressed. Thus, when the obtained optical laminate is incorporated into a display device, the effect of suppressing light reflection between two adjacent layers is excellent.

The in-plane average refractive index of the adhesive layer (1) can be controlled by the kind of the component constituting the adhesive layer (1), a combination thereof, and the like.

In the present invention, the in-plane average refractive index of the adhesive layer (1) is a refractive index at a wavelength of 589nm, and can be measured using an Abbe refractometer or the like. Specifically, the measurement can be performed, for example, by the method described in examples described below. The average refractive index in each plane of the hard coat layer described later can be measured in the same manner.

In one embodiment of the present invention, the in-plane average refractive index n1 of the hard coat layer is, for example, preferably 1.30 to 1.60, and more preferably 1.40 to 1.55. If the in-plane refractive index of the hard coat layer is in the above range, the light reflection suppressing effect at the interface with the adhesive layer (1) is easily improved. The in-plane average refractive index of the hard coat layer can be controlled by the kind of the component constituting the hard coat layer, a combination thereof, and the like.

In one embodiment of the present invention, the in-plane average refractive index n2 of the liquid crystal retardation film adjacent to the adhesive layer (1) is preferably 1.50 to 1.70, more preferably 1.50 to 1.60, for example. If the in-plane refractive index of the liquid crystal phase difference film is in the above range, the light reflection suppressing effect at the interface with the adhesive layer (1) is easily improved. The in-plane average refractive index of the liquid crystal retardation film can be controlled by the kind of the component constituting the liquid crystal retardation film, a combination thereof, and the like. The in-plane average refractive index of the liquid crystal retardation film is a refractive index at a wavelength of 589nm, and can be measured using a polarization measuring device such as KOBRA-WR (manufactured by prince measuring instruments Co., ltd.). When the liquid crystal retardation film includes a retardation liquid crystal cured film and an alignment film, the in-plane average refractive index of the liquid crystal retardation film is a value measured in a state where the two films are combined.

In one embodiment of the present invention, it is advantageous to control the difference (absolute value difference: |n3-n1|) between the in-plane average refractive index n3 of the adhesive layer (1) and the in-plane average refractive index n1 of the hard coat layer to preferably 0.25 or less, more preferably 0.15 or less. If the difference between the refractive index n3 of the adhesive layer (1) and the refractive index n1 of the hard coat layer is not more than the upper limit, an effect of suppressing light reflection at the interface between these 2 layers can be expected. The smaller the difference is, the more preferable is, and the more preferable is 0 from the viewpoint of obtaining an excellent reflection suppressing effect.

In one embodiment of the present invention, it is advantageous to control the difference (absolute value difference: |n3-n2|) between the in-plane average refractive index n3 of the adhesive layer (1) and the in-plane average refractive index n2 of the liquid crystal phase difference film to be preferably 0.15 or less, more preferably 0.05 or less. If the difference between the refractive index n3 of the adhesive layer (1) and the refractive index n2 of the liquid crystal phase difference film is not more than the upper limit, an effect of suppressing light reflection at the interface between these 2 layers can be expected. The smaller the difference is, the more preferable is, and the more preferable is 0 from the viewpoint of obtaining an excellent reflection suppressing effect.

In one embodiment of the present invention, it is preferable that the refractive index difference between the hard coat layer and the adhesive layer (1) (hereinafter, also referred to as "refractive index difference Δn1") and the refractive index difference between the adhesive layer (1) and the liquid crystal cured film (hereinafter, also referred to as "refractive index difference Δn2") are equal to or less than the upper limit. If the refractive index difference is equal to or less than the upper limit, the interference between the light reflection at the interface between the hard coat layer and the adhesive layer (1) and the light reflection at the interface between the adhesive layer (1) and the liquid crystal retardation film is less likely to occur, and the light reflection suppressing effect can be further improved. In one embodiment of the present invention, the difference (absolute value difference: |Δn1- Δn2|) between the refractive index difference Δn1 and the refractive index difference Δn2 is preferably 0.05 or less, more preferably 0.03 or less.

The refractive index n1, the refractive index n2, the refractive index n3, and the difference therebetween can be controlled by appropriately selecting the composition of the hard coat layer, the adhesive layer (1), the liquid crystal retardation film, in particular, the kind of the compound constituting each layer, the combination thereof, the alignment state of the liquid crystal retardation film, and the like. In particular, by adjusting the refractive index of the adhesive layer (1) and the hard coat layer having no light absorption anisotropy so as to be close to the in-plane average refractive index in the transmission axis direction of the liquid crystal phase difference film, it is possible to ensure the high optical characteristics required for the phase difference film and effectively suppress the light reflection generated at the interface of the hard coat layer and the adhesive layer (1) and the interface of the adhesive layer (1) and the liquid crystal phase difference film.

In one embodiment of the present invention, the hard coat layer is preferably a layer formed from a curable composition containing an active energy ray-curable component. Examples of the curable composition capable of forming a hard coat layer include a cationic polymerizable composition containing a cationic polymerizable compound as a curable compound, a radical polymerizable composition containing a radical polymerizable compound as a curable compound, and a composition containing a mixture of both a cationic polymerizable compound and a radical polymerizable compound. Among them, a cationically polymerizable active energy ray-curable composition containing a cationically polymerizable compound and a photo-cationic polymerization initiator and a radically polymerizable active energy ray-curable composition containing a radically polymerizable compound and a photo-radical polymerization initiator are preferable. In particular, if the adhesive layer (1) and the hard coat layer each contain a (meth) acrylic compound, the refractive index difference between the hard coat layer and the adhesive layer (1) can be easily controlled, and the effect of suppressing light reflection at the interface between them is excellent. In addition, the adhesion between these layers can be improved. Specific examples of the cationically polymerizable compound include an epoxy compound having 1 or more epoxy groups in the molecule, an oxetane compound having 1 or more oxetane rings in the molecule, and a vinyl compound. Specific examples of the radical polymerizable compound include (meth) acrylic compounds and vinyl compounds each having 1 or more (meth) acryloyl groups in the molecule. The curable composition may contain 1 or 2 or more cationic polymerizable compounds, and/or may contain 1 or 2 or more radical polymerizable compounds.

The hard coat layer can be formed by the same method as described as the method for forming the adhesive layer (1).

The thickness of the hard coat layer is preferably 0.1 to 5. Mu.m, more preferably 0.5 to 5. Mu.m, still more preferably 1.0 to 3. Mu.m.

The optical laminate of the present invention can be produced, for example, by a method comprising the step of applying an adhesive composition (1) to one surface of a polarizing film and bonding the polarizing film to a liquid crystal retardation film via an adhesive layer (1) formed from the adhesive composition (1). In this case, it is preferable to laminate the liquid crystal retardation film so that the slow axis (optical axis) and the absorption axis of the polarizing film are substantially 45 °. By stacking such that the slow axis (optical axis) of the liquid crystal phase difference film and the absorption axis of the polarizing film are substantially 45 °, a function as a circularly polarizing plate can be obtained.

The optical laminate of the present invention is less likely to cause a decrease in the phase difference value and is excellent in the light reflection suppressing effect, and therefore can be expected to have high optical characteristics, and for example, can be suitably used as a constituent material of an organic EL display device or the like as a circularly polarizing plate.

The display device is a device having a display element, and includes a light emitting element or a light emitting device as a light emitting source. Examples of the display device include a liquid crystal display device, an organic Electroluminescence (EL) display device, an inorganic Electroluminescence (EL) display device, a touch panel display device, an electron emission display device (for example, a field emission display device (FED), a surface field emission display device (SED)), an electronic paper (a display device using electronic ink or an electrophoretic element), a plasma display device, a projection display device (for example, a Grating Light Valve (GLV) display device, a display device having a Digital Micromirror Device (DMD)), and a piezoelectric ceramic display. The liquid crystal display device includes any one of a transmissive liquid crystal display device, a semi-transmissive liquid crystal display device, a reflective liquid crystal display device, a direct-view liquid crystal display device, a projection liquid crystal display device, and the like. These display devices may be display devices that display two-dimensional images, or may be stereoscopic display devices that display three-dimensional images. In particular, the optical laminate of the present invention can be suitably used for organic Electroluminescence (EL) display devices and inorganic Electroluminescence (EL) display devices, and also can be suitably used for liquid crystal display devices and touch panel display devices. These display devices can exhibit good image display characteristics because the optical laminate of the present invention has excellent durability and high visibility.

[ Example ]

Hereinafter, the present invention will be described more specifically by way of examples and comparative examples, but the present invention is not limited to these examples. Unless otherwise specified, "parts" and "%" in examples and comparative examples are "parts by mass" and "% by mass".

1. Preparation of adhesive composition

The curable components were stirred and mixed for 30 minutes according to the compositions shown in table 1. Next, a polymerization initiator was added and stirred and mixed for 24 hours, thereby preparing an adhesive composition (a) to an adhesive composition (J). In table 1, the polymerization initiator represents the fraction of the solid content.

[ Table 1]

The abbreviations of the components used in table 1 are as follows.

UA-122P urethane acrylate oligomer (trade name "UA-122P", manufactured by Xinzhongcun chemical Co., ltd., viscosity: 45,000 mPa.s/40 ℃ C., molecular weight: 1100g/mol, (meth) acrylate base: 2)

4-HBA 4-hydroxybutyl acrylate (trade name "4-HBA", manufactured by Osaka organic chemical Co., ltd., viscosity: 5.5 mPa.s, molecular weight: 144.2g/mol, refractive index: 1.46)

A-LEN-10 ethoxylated ortho-phenylphenol acrylate (trade name "A-LEN-10", manufactured by Xinzhongcun chemical Co., ltd., viscosity: 130 mPa.s/25 ℃ C., molecular weight: 268.31g/mol, refractive index: 1.58)

M-600A 2-hydroxy-3-phenoxypropyl acrylate (trade name "M-600A", manufactured by Kyowa chemical Co., ltd., viscosity: 150 to 200 mPa.s/25 ℃ C., molecular weight: 222.24g/mol, refractive index: 1.53)

Omnirad 819-bis (2, 4, 6-trimethylbenzoyl) phenylphosphine oxide (trade name "Omnirad819", manufactured by IGM Co., ltd.) having a molecular weight of 418.5g/mol, a molar absorption coefficient at 400nm of 1125L. Mol ^-1·cm^-1)

2. Fabrication of optical laminate

Example 1]

(1) Production of laminated film with polarizing film

(I) Preparation of composition (1) for Forming photo-alignment film

The copolymer (1) having the following structure was produced by the following procedure. In the following structure, l, m, and n are integers of 0 to 100, respectively, satisfying l+m+n=100.

To a solution obtained by dissolving 4- ((6- (methacryloyloxy) hexyl) oxy) benzoic acid in toluene together with an amine catalyst, chlorodimethyl ether was added dropwise, and after that, the reaction was carried out by heating to 40 ℃ and maintaining, and then, the reaction solution was cooled and water was added. The organic layer was separated from the obtained mixed solution, and a 50% aqueous acetic acid solution was added to the separated organic layer and stirred to obtain a mixture. The organic layer was separated from the resulting mixture, and the separated organic layer was concentrated to give methoxymethyl 4- ((6- (methacryloyloxy) hexyl) oxy) benzoate.

Methoxy methyl 4- ((6- (methacryloyloxy) hexyl) oxy) benzoate 8.8g (25.2 mmol), 6- (4-hydroxyphenoxy) hexyl methacrylate 1.0g (3.6 mmol), 4- ((6-methyl (acryloyloxy) hexyl) oxy) phenyl (E) -3- (4-methoxyphenyl) acrylate 3.2g (7.2 mmol) and 2,2' -azobis (2, 4-dimethylpentanenitrile) 0.2g were dissolved in tetrahydrofuran. After nitrogen was introduced into the solution for 1 hour, the solution was heated to 60 ℃ and maintained, and the reaction was performed, and the reaction solution was cooled to room temperature. To the reaction solution was added 1.1g (3.6 mmol) of 4- ((6- (methacryloyloxy) hexyl) oxy) benzoic acid and 1-ethyl-3- (3-dimethylaminopropyl) carbodiimide hydrochloride to give a mixed solution. The reaction was allowed to proceed by heating the mixture to 40 ℃, and then the reaction solution was cooled. Methanesulfonic acid was added to the reaction solution at room temperature, and after heating to 70 ℃, the reaction solution was cooled to around room temperature. The cooled reaction solution was added dropwise to n-hexane to form a precipitate, and the precipitate was recovered and dried under reduced pressure, whereby a polymer was obtained. The weight average molecular weight of the copolymer (1) was measured by GPC and found to be 24000.

Next, 2 parts of the obtained copolymer (1) and 98 parts of propylene glycol methyl ether acetate were mixed to obtain a mixture. The resultant mixture was stirred at 80 ℃ for 1 hour, thereby obtaining a composition (1) for forming a photo-alignment film.

(Ii) Preparation of composition for Forming polarizing film

The following ingredients were mixed and stirred at 80 ℃ for 1 hour, thereby obtaining a composition for forming a polarizing film. The polymerizable liquid crystal compound (Y1), the polymerizable liquid crystal compound (Y2), and the dichroic dye (DP 1) to (DP 3) each have the following structures.

75 Parts of polymerizable liquid crystal compound (Y1)

25 Parts of polymerizable liquid crystal compound (Y2)

Dichroic dye (DP 1) 2.5 parts

Dichroic dye (DP 2) 2.5 parts

Dichroic dye (DP 3) 2.5 parts

6 Parts of a polymerization initiator [ 2-dimethylamino-2-benzyl-1- (4-morpholinophenyl) butan-1-one (Irgacure (registered trademark) 369, manufactured by BASF Japan Co., ltd.)

1.2 Parts of a leveling agent [ polyacrylate Compound (BYK-361N; BYK-Chemie Co.) ]

Solvent [ o-xylene ]:250 parts

Polymerizable liquid crystal compound (Y1)

Polymerizable liquid crystal compound (Y2)

Dichroic pigment (DP 1)

Dichroic pigment (DP 2)

Dichroic pigment (DP 3)

(Iii) Production of laminated film with polarizing film

Corona treatment is applied to the surface of the hard coat layer of the release film with the hard coat layer. A composition (1) for forming a photo-alignment film was applied to the corona-treated surface by a coating device, dried at 80℃for 1 minute, and subjected to polarized UV exposure (cumulative light amount at a wavelength of 313nm under an air atmosphere: 50mJ/cm ²) at a cumulative light amount of 50mJ/cm ² by using a polarized UV irradiation device (SPOTCURESP-9 with polarizer unit; manufactured by USHIO motor Co., ltd.) to form a photo-alignment film (1).

The thickness of the obtained photo-alignment film (1) was measured by ellipsometer M-220 (manufactured by Nippon Spectrometry Co., ltd.), and the result was 100nm.

The obtained photo-alignment film (1) was coated with the composition for forming a polarizing film using a coating apparatus, and then dried by heating in a drying oven set at 120 ℃ for 1 minute, thereby obtaining a dried film. Next, ultraviolet rays (cumulative light amount at 365nm in wavelength: 500mJ/cm ² under nitrogen atmosphere) were irradiated to the dry film side of the composition for forming a polarizing film using a UV irradiation apparatus (Unicure VB-15201BY-A, manufactured BY USHIO Motor Co., ltd.) to thereby form a polarizing film in which a polymerizable liquid crystal compound and a dichroic dye were oriented, and a laminate film with a polarizing film comprising a release film/a hard coat layer/a photo-alignment film (1)/a polarizing film was obtained.

The thickness of the polarizing film was measured by ellipsometer M-220 (manufactured by Nippon Spectrometry Co., ltd.) and found to be 2.0. Mu.m. Next, the polarizing film was subjected to X-ray diffraction measurement using an X' -PertPROMPD (manufactured by spectra corporation), and as a result, a sharp diffraction peak (bragg peak) having a peak half-value width (FWHM) =about 0.17 ° was obtained in the vicinity of 2θ=20.2 °. The ordered period (d) obtained from the peak position was about 4.4 a, confirming that a structure reflecting the higher order smectic phase was formed.

(2) Production of laminated film with phase-difference film (1)

(I) Preparation of composition (2) for Forming photo-alignment film

Light-oriented materials of the following structure (weight average molecular weight: 50000, m: n=50:50) were produced according to the method described in japanese patent application laid-open No. 2021-196514. The photo-alignment film-forming composition (2) was prepared by mixing 2 parts by mass of the photo-alignment material and 98 parts by mass of cyclopentanone (solvent) as components, and stirring the resultant mixture at 80 ℃ for 1 hour.

(Ii) Preparation of composition (1) for Forming a retardation film

A polymerizable liquid crystal compound (X1) and a polymerizable liquid crystal compound (X2) each having a structure shown below were prepared.

Polymerizable liquid crystal compound (X1):

polymerizable liquid crystal compound (X2):

1mg of the polymerizable liquid crystal compound (B1) was dissolved in 10mL of chloroform to obtain a solution. The obtained solution was added to a measurement cuvette having an optical path length of 1cm as a measurement sample, and the measurement sample was set in an ultraviolet-visible spectrophotometer (manufactured by Shimadzu corporation, "UV-2450"), to measure an absorption spectrum. The wavelength at which the maximum absorbance is reached is read from the obtained absorption spectrum, and as a result, the maximum absorption wavelength λmax in the range of 300 to 400nm is 356nm.

The polymerizable liquid crystal compound (X1) and the polymerizable liquid crystal compound (X2) were mixed at a mass ratio of 90:10 to obtain a mixture. To 100 parts by mass of the resultant mixture, 0.1 part by mass of a leveling agent "BYK-361N" (BMChemie Co., ltd.) and 3 parts by mass of "Irgacure OXE-03" (BASF Japan Co., ltd.) as a photopolymerization initiator were added. Further, N-methyl-2-pyrrolidone (NMP) was added so that the solid content concentration became 13 mass%. The mixture was stirred at a temperature of 80 ℃ for 1 hour, thereby obtaining a composition (1) for forming a retardation film.

(Iii) Production of laminated film with liquid Crystal phase-difference film

The release surface of the release film is subjected to corona treatment, and the composition (2) for forming a photo-alignment film is applied to the surface of the release film subjected to corona treatment by an adhesive application device. The obtained coating film was dried at 120 ℃ for 2 minutes, and then cooled to room temperature, thereby forming a dried film. Then, 100mJ (based on 313 nm) of polarized ultraviolet light was irradiated by using a UV irradiation device (SPOTCURESP-9; manufactured by USHIO Motor Co., ltd.) to obtain a photo-alignment film (2).

The film thickness of the photo-alignment film (2) was measured by using an ellipsometer M-220 manufactured by Japan light splitting Co., ltd., and as a result, the film thickness of the photo-alignment film (2) was 100nm.

The composition (1) for forming a retardation film is applied to the obtained photo-alignment film (2) by a coating apparatus to form a coating film. The coated film was dried by heating at 120 ℃ for 2 minutes and then cooled to room temperature, to obtain a dried film. Next, a retardation liquid crystal cured film (1) in which a polymerizable liquid crystal compound was cured in a state of being oriented in the horizontal direction with respect to the substrate surface was formed BY irradiating the dried film with ultraviolet light having an exposure of 500mJ/cm ² (based on 365 nm) under a nitrogen atmosphere using a high-pressure mercury lamp (manufactured BY USHIO Motor Co., ltd. "Unicure VB-15201 BY-A"), to obtain a laminated film with a liquid crystal retardation film (1). The resulting laminated film with the liquid crystal retardation film (1) was composed of a release film/liquid crystal retardation film (1)/(photo-alignment film (2)/retardation liquid crystal cured film (1) (horizontal alignment liquid crystal cured film)).

The film thickness of the cured retardation liquid crystal film (1) was measured using a laser microscope lexthols 4100 manufactured by olympus corporation, and as a result, the film thickness of the cured retardation liquid crystal film (1) was 2.0 μm.

(Iv) In-plane retardation measurement of liquid crystal retardation film (1)

Corona treatment is applied to the surface side of the liquid crystal retardation film (1) of the laminate film with the liquid crystal retardation film (1). An acrylic adhesive of 25 μm was laminated on the corona treated surface, and the laminate was bonded to glass via the acrylic adhesive. The release film was peeled from the obtained laminate to obtain a retardation evaluation laminate having a structure of liquid crystal retardation film (1)/acrylic adhesive/glass.

The retardation evaluation laminate thus obtained was used to measure the in-plane retardation of the liquid crystal retardation film (1) by means of KOBRA-WR manufactured by prince measuring instruments Co. The in-plane phase difference values for light having wavelengths of 450nm, 550nm and 650nm were obtained by the Cauchy dispersion formula obtained from the measurement results of the in-plane phase difference values for light having wavelengths of 448.2nm, 498.6nm, 548.4nm, 587.3nm, 628.7nm and 748.6 nm.

As a result, the in-plane phase difference values Re (450) =122 nm, re (550) =140 nm, and Re (650) =144 nm, and the relationship of the in-plane phase difference values at the respective wavelengths is as follows.

Re(450)/Re(550)=0.87

Re(650)/Re(550)=1.03

Re (450) represents the in-plane phase difference value with respect to light having a wavelength of 450nm, re (550) represents the in-plane phase difference value with respect to light having a wavelength of 550nm, and Re (650) represents the in-plane phase difference value with respect to light having a wavelength of 650 nm.

(3) Production of laminated film with liquid Crystal phase-difference film (2)

(I) Preparation of composition for Forming vertical alignment film

As the composition for forming a vertical alignment film, a mixture in which 2-phenoxyethyl acrylate, tetrahydrofurfuryl acrylate, dipentaerythritol triacrylate, and bis (2-ethyleneoxyethyl) ether were mixed at a ratio of 1:1:4:5, and LUCIRINTPO as a polymerization initiator was added at a ratio of 4 mass% to the composition for forming a vertical alignment film was used.

(Ii) Preparation of composition (2) for Forming a retardation film

A mixed solvent was prepared in which Methyl Ethyl Ketone (MEK), methyl isobutyl ketone (MIBK) and Cyclohexanone (CHN) were mixed at a mass ratio (MEK: MIBK: CHN) of 35:30:35. A composition (2) for forming a retardation film was prepared by mixing 100 parts by mass of the above mixed solvent with a photopolymerizable nematic liquid crystal compound (RMM 28B, manufactured by Merck Co., ltd.) so that the solid content was 1 to 1.5 parts by mass.

(Iii) Production of laminated film with liquid Crystal phase-difference film (2)

A composition for forming a homeotropic alignment film was applied to a release treated surface of a release treated polyethylene terephthalate film (thickness: 38 μm), and irradiated with ultraviolet light of 200mJ/cm ² to prepare a homeotropic alignment film. The film thickness of the obtained vertical alignment film was 3.0. Mu.m.

The composition (2) for forming a phase difference film is applied to the vertical alignment film by die coating. The coating liquid was dried at a drying temperature of 75 ℃ and a drying time of 120 seconds. Then, ultraviolet (UV) light is irradiated to the coating film to polymerize the polymerizable liquid crystal compound, thereby obtaining a laminated film with a liquid crystal retardation film (2). The resulting laminated film with a liquid crystal retardation film (2) was constituted of a liquid crystal retardation film (2) (retardation liquid crystal cured film (2)/homeotropic alignment film)/polyethylene terephthalate film. The film thickness of the liquid crystal retardation film (2) was measured using a laser microscope lexthols 4100 manufactured by olympus corporation, and as a result, the film thickness of the liquid crystal retardation cured film (2) was 1.0 μm.

(4) Production of laminate 01

Corona treatment is applied to the surfaces of the liquid crystal retardation films of the laminated film with the liquid crystal retardation film (1) and the laminated film with the liquid crystal retardation film (2), and the liquid crystal retardation film (1) and the liquid crystal retardation film (2) are bonded to each other by the cationic adhesive composition so as to form bonding surfaces. Next, ultraviolet rays were irradiated to cure the cationic adhesive composition, thereby producing a laminate 01. The laminate 01 thus obtained was composed of a release film/liquid crystal retardation film (1) (photo alignment film (2)/retardation liquid crystal cured film (1))/cationic adhesive layer/liquid crystal retardation film (2) (retardation liquid crystal cured film (2)/homeotropic alignment film)/polyethylene terephthalate film (release film).

(5) Production of laminate (A-1)

The release film of the laminated film with the polarizing film was peeled off, and the surface of the hard coat layer was subjected to corona treatment. The release film on the liquid crystal retardation film (1) side of the laminate (01) is peeled off, the surface of the photo-alignment film (2) is subjected to corona treatment, and the adhesive composition (A) is applied to the corona-treated surface by using an applicator to form a coating layer. The hard coat layer subjected to the corona treatment is surface-laminated on the obtained coating layer.

An ultraviolet irradiation device (lamp: mercury lamp manufactured by EYE GRAPHICS) with a conveyor belt was used to irradiate UV light from the liquid crystal retardation film (1) side of the obtained laminate with an accumulated light amount of 400mJ/cm ² (UV-B), and the adhesive composition (a) was cured to obtain a laminate (a-1).

The laminate (a-1) thus obtained was constituted of a polarizing film/a photo-alignment film (1)/a hard coat layer/an adhesive layer (cured product layer of the adhesive composition (a)/a liquid crystal retardation film (1) (photo-alignment film (2)/a cured liquid crystal retardation film (1))/a cationic adhesive layer/a liquid crystal retardation film (2) (cured liquid crystal retardation film (2)/a homeotropic alignment film)/a polyethylene terephthalate film (release film). The thickness of the cured layer of the adhesive composition A was 2. Mu.m.

(6) Production of laminate 02

The surface of the norbornene resin film having a thickness of 25 μm was subjected to corona treatment. Next, an acrylic pressure-sensitive adhesive layer a side of a release film with a pressure-sensitive adhesive layer comprising an acrylic pressure-sensitive adhesive layer a having a thickness of 5 μm and a release film was laminated on the corona-treated surface of the norbornene-based resin film. Thus, a laminate 02 of a norbornene resin film/an acrylic pressure-sensitive adhesive layer a/a release film was produced.

(7) Production of laminate (B-1)

Corona treatment was performed on the polarizing film side of the laminate (a-1). Next, the release film of the laminate 02 was peeled off, and the laminate was bonded to the corona-treated surface of the laminate (a-1) on the acrylic pressure-sensitive adhesive layer a side of the laminate 02, to obtain a laminate. The release film on the liquid crystal retardation film (2) side of the obtained laminate was peeled off, and the surface of the vertical alignment film was subjected to corona treatment. On the corona-treated surface, a laminate (B-1) was obtained by laminating on the pressure-sensitive adhesive layer B side of the pressure-sensitive adhesive layer-equipped release film comprising the acrylic pressure-sensitive adhesive layer B having a thickness of 20 μm and the release film. The laminate (B-1) thus obtained was composed of norbornene-based resin film/acrylic adhesive layer A/polarizing film/photo-alignment film (1)/hard coat layer/adhesive layer (cured product layer of adhesive composition A)/liquid crystal retardation film (1) (photo-alignment film (2)/cured phase difference liquid crystal film (1))/cationic adhesive layer/liquid crystal retardation film (2) (cured phase difference liquid crystal film (2)/homeotropic alignment film)/acrylic adhesive layer B/release film.

(8) Production of laminate 03

A single surface of a norbornene resin Film (Zeonor Film ZF-14) having a thickness of 25 μm was subjected to corona treatment. The release film on the liquid crystal retardation film (1) side of the laminate (01) is peeled off, and the surface of the photo-alignment film (2) is subjected to corona treatment. Next, an adhesive composition A was applied to the corona-treated surface by using an applicator (AGF-B10; manufactured by CHUNYAKO Co., ltd.). The obtained coating layer was laminated on the corona-treated surface side of a norbornene resin film having a thickness of 25. Mu.m, to obtain a laminate. The obtained laminate was irradiated with UV light from the laminate 01 side using an ultraviolet irradiation device (lamp EYE GRAPHICS mercury lamp) with a conveyor belt to a cumulative light amount of 400mJ/cm ² (UV-B), and the coating layer was cured, thereby obtaining a laminate 03. The laminate 03 thus obtained was composed of a norbornene resin film/an adhesive layer (cured layer of adhesive composition a)/a liquid crystal retardation film (1) (photo-alignment film (2)/a cured retardation liquid crystal film (1))/a cationic adhesive layer/a liquid crystal retardation film (2) (cured retardation liquid crystal film (2)/a vertical alignment film)/a mold release film.

(9) Production of laminate (C-1)

The release film was peeled from the obtained laminate 03, and the vertical alignment film was subjected to corona treatment. The corona-treated surface was laminated on the pressure-sensitive adhesive layer B side of a release film with a pressure-sensitive adhesive layer comprising an acrylic pressure-sensitive adhesive layer B having a thickness of 20 μm and the release film, to obtain a laminate (C-1).

The laminate (C-1) thus obtained was constituted of a norbornene-based resin film/an adhesive layer (cured product layer of adhesive composition A)/a liquid crystal retardation film (1) (photo-alignment film (2)/a cured retardation liquid crystal film (1))/a cationic adhesive layer/a liquid crystal retardation film (2) (cured retardation liquid crystal film (2)/a vertical alignment film)/an acrylic adhesive layer B/a release film.

< Examples 2 to 8, comparative examples 1 and 2>

The adhesive compositions (A) used in example 1 were replaced with the adhesive compositions (B) to (J), respectively, to prepare laminates (A-2) to (A-10), laminates (B-2) to (B-10), and laminates (C-2) to (C-10).

The laminate structures of examples 2 to 8 and comparative examples 1 and 2 were as follows.

The laminate using the adhesive composition (B) was a laminate (A-2), a laminate (B-2) or a laminate (C-2) (example 2).

The laminate using the adhesive composition (C) was laminate (A-3), laminate (B-3) or laminate (C-3) (example 3).

The laminate using the adhesive composition (D) was laminate (A-4), laminate (B-4) or laminate (C-4) (example 4).

The laminate using the adhesive composition (E) was laminate (A-5), laminate (B-5) or laminate (C-5) (example 5).

The laminate using the adhesive composition (F) was laminate (A-6), laminate (B-6) or laminate (C-6) (example 6).

The laminate using the adhesive composition (G) was laminate (A-7), laminate (B-7) or laminate (C-7) (example 7).

The laminate using the adhesive composition (H) was laminate (A-8), laminate (B-8) or laminate (C-8) (example 8).

The laminate using the adhesive composition (I) was a laminate (A-9), a laminate (B-9) or a laminate (C-9) (comparative example 1).

The laminate using the adhesive composition (J) was a laminate (A-10), a laminate (B-10) or a laminate (C-10) (comparative example 2).

3. Evaluation of optical laminate

(1) Measurement of thickness

For the measurement of the thickness of each layer, unless otherwise specified, a digital micrometer "MH-15M" manufactured by Nikon, inc. was used.

(2) Refractive index (n 3) of cured layer (adhesive layer) of adhesive composition

The adhesive compositions (a) - (J) used in examples and comparative examples were applied to one side of a stretched norbornene resin Film (Zeonor Film, japan ZEON corporation) using an adhesive application device (manufactured by first physicochemical corporation) so that the thickness after irradiation with ultraviolet light became about 30 μm, and the stretched norbornene resin Film was further covered on the applied surface to obtain a laminate comprising the stretched norbornene resin Film/the adhesive composition/the stretched norbornene resin Film. Then, the laminate was irradiated with ultraviolet light at an accumulated light amount of 400mJ/cm ² (UV-B) by an ultraviolet irradiation device (lamp: mercury lamp manufactured by EYE GRAPHICS Co.) with a belt conveyor, and the adhesive composition was cured. The norbornene resin film was peeled off from the laminate after ultraviolet irradiation by 2 sheets, and a cured product of the adhesive composition was obtained. The refractive index (589 nm) of the obtained cured product was measured in a 25℃environment using a multi-wavelength Abbe refractometer (manufactured by ATAGO Co., ltd. "DR-M2").

(3) Refractive index of hard coat layer (n 1)

The in-plane average refractive index of the hard coat layer was measured in the following manner.

The release film of the release film having the hard coat layer was peeled off, and the refractive index (589 nm) of the cured product layer was measured using a multi-wavelength Abbe refractometer (DR-M2, manufactured by ATAGO Co., ltd.) under a 25 ℃.

The in-plane average refractive index of the hard coat layer was 1.52.

(4) Refractive index of liquid Crystal phase film (n 2)

The in-plane average refractive index of the liquid crystal retardation film was measured in the following manner.

The laminate (retardation film (1)/acrylic adhesive/glass) was evaluated for retardation by in-plane retardation measurement, and the in-plane refractive indices nx and ny at 589nm were measured by KOBRA-WR manufactured by prince measuring instruments Co. Using nx and ny, the in-plane average refractive index n was calculated according to the following formula.

n=(nx+ny)/2

(Wherein nx represents a refractive index in a slow axis direction in a film plane, ny represents a refractive index in a fast axis direction in the film plane, and n represents an in-plane average refractive index.)

The in-plane average refractive index of the liquid crystal phase difference film (1) was 1.59.

The values of the following formulas were calculated from the in-plane average refractive index n1 of the hard coat layer, the in-plane average refractive index n2 of the liquid crystal retardation film, and the in-plane average refractive index n3 of each adhesive layer obtained as described above.

|(n1×n2)^1/2-n3|

The results are shown in Table 2.

(5) Evaluation of coatability

The release film on the liquid crystal retardation film (1) side of the laminate (01) was peeled off, and the photo-alignment film (2) was subjected to 1 treatment using a corona treatment device (AGF-B10; manufactured by CHUN motor Co., ltd.) at an output of 0.8kW and a treatment rate of 10 m/min. Next, the adhesive composition (a) was applied to each of the corona treated surfaces, and the surfaces were left to stand at 23 ℃ and 55% humidity for 10 minutes. Then, whether or not the curable adhesive composition could be applied without shrinkage or film thickness unevenness was visually confirmed, and the coatability was evaluated. The evaluation criteria are as follows.

A, the coating film is uniform and can be applied without shrinkage and uneven film thickness

B, although the coating was possible, it was confirmed that a part of the coating was contracted and the film thickness was uneven

C difficult to apply

The adhesive composition (a) was replaced with the adhesive composition (B) to the adhesive composition (J), and the same evaluation was performed. The results are shown in Table 2.

(6) Viscosity measurement

The viscosities of the coating solutions of the adhesive compositions (A) to (J) used in the examples and comparative examples were measured by an E-type viscometer (manufactured by DONGMACHINESE CORPORATION) in accordance with JISK 7117-2. The results are shown in Table 2.

(7) Evaluation of adhesion force

The laminate (B-1) was cut into a size of 200mm in length (parallel to the absorption axis direction of the polarizing plate) and 25mm in width, and the release film on the side of the acrylic pressure-sensitive adhesive layer B was peeled off and bonded to a glass plate to obtain an evaluation sample. A blade of a cutter was inserted into the laminate (B-1) of the obtained evaluation sample, the laminate was peeled off from the end portion by 30mm in the longitudinal direction, and the peeled portion was held by a holding portion of a tester, and the glass plate was held by a holding portion. The laminate (B-1) in this state was subjected to a peel test at a holding speed of 300 mm/min in accordance with JISK6854-2:1999 "adhesive-peel adhesion test method-section 2:180 degree peel" in an atmosphere having a temperature of 23℃and a relative humidity, and when the position at which the peeling was started was set to 0mm, the average peel force in the length range of 50mm to 100mm was obtained and was used as the peel strength (N) of the laminate (B-1).

The peel strength was measured after the laminate (B-1) was bonded to glass and left to stand in an atmosphere of a relative humidity of 50% rh at a temperature of 23 ℃ for 24 hours.

The laminate (B-1) was replaced with the laminate (B-2) to the laminate (B-10), and the evaluation was performed in the same manner. The evaluation criteria are as follows. The results are shown in Table 2.

A, peel strength greater than 0.8N, peel interface not between adhesive and adjacent layers

The peel strength between the adhesive and the adjacent layer is 0.2-0.8N

The adhesive has a peel strength from the adjacent layer of 0.2N or less

(8) Evaluation of durability of polarizing plate

The laminate (C-1) was cut into a size of 30 mm. Times.30 mm, and the release film on the adhesive layer B side of the laminate (C-1) was peeled off and bonded to an alkali-free glass (manufactured by Corning Co., ltd. "EagleXG") of 40 mm. Times.40 mm to obtain an evaluation sample. A heating experiment was performed at a temperature of 105℃for 30 minutes, and the phase difference (Re) of the evaluation samples before and after the experiment was evaluated at a measurement wavelength of 589 nm. The phase difference value (Re) and the phase difference value variation (Δre) are defined as follows.

Re=(nx-ny)×d

(Wherein nx represents a refractive index in a slow axis direction in a film plane, ny represents a refractive index in a fast axis direction in the film plane, and d represents a film thickness.)

Δre= (phase difference after heating) - (phase difference before heating)

The laminate (B-1) was replaced with the laminate (B-2) to the laminate (B-10), and the evaluation was performed in the same manner. The results are shown in Table 2.

In comparative example 1, the coating property was poor, and a sample could not be produced, so that the peel strength and durability could not be evaluated.

[ Table 2]

< Examples 9 to 12 and comparative example 3>

(1) Preparation of adhesive composition

The curable compound was stirred and mixed for 30 minutes according to the composition shown in table 3. Then, a polymerization initiator was added and stirred and mixed for 24 hours, thereby preparing an adhesive composition (K) to an adhesive composition (O). In table 3, the polymerization initiator represents the fraction of the solid content.

[ Table 3]

The abbreviations of the components used in Table 3 are as follows.

UV-3000B urethane acrylate oligomer (manufactured by Mitsubishi Chemical Corporation under the trade name "UV-3000B", viscosity: 40000-60000 mPa.s/60 ℃ C., molecular weight: 18000g/mol, (meth) acrylate base: 2)

UV-3700B urethane acrylate oligomer (manufactured by Mitsubishi Chemical Corporation under the trade name "UV-3700B", viscosity: 30000 to 60000 mPa.s/60 ℃ C., molecular weight: 38000g/mol, (meth) acrylate base: 2)

The curable compounds b to d, the polymerization initiator and the adhesive compositions (A) to (J) are the same.

(2) Fabrication of optical laminate

The adhesive compositions (A) used in example 1 were replaced with the adhesive compositions (K) to (O), respectively, to prepare laminates (A-11) to (A-15), laminates (B-11) to (B-15), and laminates (C-11) to (C-15).

The laminate structures of examples 9 to 12 and comparative example 3 were as follows.

The laminate using the adhesive composition (K) was laminate (A-11), laminate (B-11) or laminate (C-11) (example 9).

The laminate using the adhesive composition (L) was a laminate (A-12), a laminate (B-12) or a laminate (C-12) (example 10).

The laminate using the adhesive composition (M) was laminate (A-13), laminate (B-13) or laminate (C-13) (example 11).

The laminate using the adhesive composition (N) was laminate (A-14), laminate (B-14) or laminate (C-14) (example 12).

The laminate using the adhesive composition (O) was a laminate (A-15), a laminate (B-15) or a laminate (C-15) (comparative example 3).

(3) Evaluation of optical laminate

The physical properties and properties were measured and evaluated in the same manner as in the optical layered body of example 1. The results are shown in Table 4.

[ Table 4]

Claims (11)

1. An optical laminate comprising, in order, a polarizing film, an adhesive layer, and a liquid crystal retardation film adjacent to the adhesive layer,

The polarizing film is a cured layer of a polymerizable liquid crystal composition containing a polymerizable liquid crystal compound and a dichroic dye,

The adhesive layer is a cured product layer of an active energy ray-curable adhesive composition containing a curable compound,

A) Urethane (meth) acrylate having 2 or less (meth) acryloyl groups in the molecule;

b) (meth) acrylic acid ester having no aromatic ring in the molecule and having a hydroxyl group, and

C) (meth) acrylic acid esters having not hydroxyl groups in the molecule but more than 2 aromatic rings.

2. The optical stack according to claim 1, wherein the adhesive composition further comprises d) a (meth) acrylate having an aromatic ring and a hydroxyl group in the molecule.

3. The optical laminate according to claim 1, wherein the adhesive composition comprises 1 to 30 parts by mass of a) a urethane (meth) acrylate having 2 or less (meth) acryloyl groups in a molecule, based on 100 parts by mass of the total amount of the curable compounds contained in the adhesive composition.

4. The optical laminate according to claim 1, wherein the adhesive composition contains 15 to 60 parts by mass of a (meth) acrylate having no aromatic ring in a molecule and a hydroxyl group, based on 100 parts by mass of the total amount of the curable compounds contained in the adhesive composition.

5. The optical laminate according to claim 1, wherein the adhesive composition comprises 10 to 60 parts by mass of a (meth) acrylate having 2 or more aromatic rings and no hydroxyl group in a molecule per 100 parts by mass of a total amount of the curable compounds contained in the adhesive composition.

6. The optical laminate according to claim 2, wherein the adhesive composition comprises 3 to 40 parts by mass of d) the (meth) acrylate having an aromatic ring and a hydroxyl group in a molecule, based on 100 parts by mass of the total amount of the curable compounds contained in the adhesive composition.

7. The optical laminate according to claim 1, wherein the adhesive composition contains 0.5 to 10 parts by mass of the polymerization initiator relative to 100 parts by mass of the total amount of the curable compounds contained in the adhesive composition.

8. The optical laminate according to claim 7, wherein the polymerization initiator has a molar absorption coefficient of 10L/mol ^-1·cm^-1 or more at a light source wavelength of 400nm in an acetonitrile solvent.

9. The optical stack of claim 1, wherein a hard coat layer is further included between the polarizing film and the adhesive layer.

10. The optical laminate according to claim 1, comprising a polarizing film, an alignment film, a hard coat layer, an adhesive layer, and a liquid crystal retardation film in a sequentially adjacent manner.

11. The optical laminate according to claim 9, wherein when the in-plane average refractive index of the hard coat layer is n1, the in-plane average refractive index of the liquid crystal retardation film is n2, and the in-plane average refractive index of the adhesive layer is n3, the following formula is satisfied:

|(n1×n2)^1/2-n3|≤0.018。