JP2019091029A - Composite retardation plate, optical laminate, and image display device - Google Patents

Abstract

To provide a composite retardation plate which is less susceptible to being wrinkled at bent sections even when the plate is bent by touching a roller member during a conveying or spooling step or when the plate is placed on a surface of an image display device panel having the bent sections.SOLUTION: A composite retardation plate comprises a first retardation layer, a second retardation layer, and a first adhesive layer that bonds the first retardation layer and the second retardation layer together, and exhibits a puncture gradient of 6-15 kg/mmper unit thickness.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a composite retardation plate, an optical laminate including the composite retardation plate, and an image display apparatus including the optical laminate.

  2. Description of the Related Art Conventionally, in an image display device, a method is employed in which an optical laminate having an anti-reflection performance is disposed on the viewing side of an image display panel to suppress a decrease in visibility due to reflection of extraneous light.

  As an optical laminate having an antireflection performance, an optical laminate composed of a polarizing plate and a retardation layer is known. In the optical laminate having anti-reflection performance, extraneous light directed to the image display panel is converted to linearly polarized light by the polarizing plate, and is converted to circularly polarized light by the subsequent retardation layer. Although the extraneous light which is circularly polarized light is reflected on the surface of the image display panel, the rotational direction of the polarization plane is reversed at the time of this reflection, and after converted into linearly polarized light by the retardation layer, Ru. As a result, outgoing radiation to the outside is significantly suppressed.

  A composite retardation plate formed by bonding a plurality of retardation layers with an adhesive layer is known as a retardation plate which is a component of an optical laminate having anti-reflection performance. For example, Patent Documents 1 and 2 describe a composite retardation plate formed by bonding a half-wave layer and a quarter-wave layer with an adhesive layer.

JP, 2015-21975, A JP, 2015-21976, A

  The composite retardation plate is an optical laminate alone or as a laminate including the same, in a process of being transported, wounded, etc., by contacting a roll-like member, or on the surface of an image display panel having a bend. When the composite retardation plate is bent due to being disposed or the like, wrinkles may occur in the bent portion, which may cause quality defects. In particular, in the case where the composite retardation plate is formed of a thin film, it may occur remarkably.

  In the present invention, when the composite retardation plate is bent by contact with a roll-like member, or by being disposed on the surface of an image display panel having a bending portion, etc., in the steps of conveying, winding, etc. However, it is an object of the present invention to provide a composite retardation plate in which the occurrence of wrinkles in a bent portion is suppressed, an optical laminate including the composite retardation plate, and an image display device including the optical laminate.

The present invention provides a composite retardation plate, an optical laminate, and an image display apparatus described below.
[1] A first retardation layer, a second retardation layer, and a first adhesive layer bonding the first retardation layer and the second retardation layer,
Piercing per unit thickness gradient is ^{6kg / mm 2 ~15kg / mm 2} , the composite retardation plate.

  [2] The composite retardation plate according to [1], wherein the first adhesive layer is a cured product layer of an active energy ray-curable adhesive.

  [3] The composite retardation plate according to [1] or [2], wherein the first retardation layer is a half wavelength layer and the second retardation layer is a quarter wavelength layer.

  [4] The composite retardation plate according to [1] or [2], wherein the first retardation layer is a half wavelength layer or a quarter wavelength layer, and the second retardation layer is an optical compensation layer. .

  [5] The composite retardation plate according to any one of [1] to [4], wherein at least one of the first retardation layer and the second retardation layer includes a retardation developing layer which is a liquid crystal layer.

  [6] The composite retardation plate according to any one of [1] to [5], which has a thickness of 2 μm to 50 μm.

[7] A polarizing plate, and the composite retardation plate according to any one of [1] to [6] laminated on the polarizing plate,
The composite retardation plate is an optical laminate in which the first retardation layer is laminated in a direction toward the polarizing plate.

[8] The optical laminate according to [7], which is a circularly polarizing plate.
[9] The optical laminate according to [7] or [8], further including a second adhesive layer for adhering the polarizing plate and the composite retardation plate.

  [10] The optical laminate according to [9], wherein the second adhesive layer is a cured product layer of an active energy ray-curable adhesive.

  [11] An image display device, comprising: an image display panel; and the optical laminate according to any one of [7] to [10] disposed on the viewing side of the image display panel.

  [12] The image display device according to [11], wherein the optical laminate is disposed in a direction in which the polarizing plate is positioned on the viewing side.

  [13] The image display device according to [12], which is an organic electroluminescence display device.

  According to the composite retardation plate of the present invention, the composite retardation plate is brought into contact with the roll-like member in the process of being transported, wounded, etc., or disposed on the surface of the image display panel having a bent portion, etc. Even when the retardation plate is bent, generation of wrinkles in the bent portion can be suppressed.

FIG. 1 is a schematic cross-sectional view schematically showing an example of a composite retardation plate of the present invention. It is a schematic sectional drawing which shows typically an example of a phase difference layer provided with a liquid crystal layer as a phase difference expression layer. (A)-(C) are schematic sectional drawings which show typically an example of each manufacturing process in the manufacturing method of the composite retardation plate of this invention.

The composite retardation plate and the optical laminate of the present invention will be described below with reference to the drawings.
[Composite retarder]
FIG. 1 is a schematic cross-sectional view schematically showing an example of the composite retardation plate of the present invention. As shown in FIG. 1, the composite retardation plate 5 is a first adhesive for bonding the first retardation layer 1, the second retardation layer 2, and the first retardation layer 1 and the second retardation layer 2. And layer 4. Composite retardation plate 5, piercing slope per unit thickness is the ^{6kg / mm 2 ~15kg / mm 2} , is preferably ^{6kg / mm 2 ~12kg / mm 2} , 6.5kg / mm 2 ~ more preferably from 10 kg / mm ^2, further preferably ^{7kg / mm 2 ~10kg / mm 2} , particularly preferably ^{8kg / mm 2 ~10kg / mm 2} . By setting the piercing inclination per unit film thickness to 6 kg / mm ² or more, the occurrence of wrinkles can be suppressed even when the composite retardation plate 5 or the optical laminate including the same is bent. In addition, when the piercing inclination per unit film thickness of the composite retardation plate 5 exceeds 15 kg / mm ² , it is fine at the end portion of the composite retardation plate or the optical laminate including the same during processing such as cutting. It becomes easy to crack.

  The piercing inclination of the composite retardation plate indicates the strength when the piercing plate is pierced perpendicularly to the composite retardation plate and the composite retardation plate is torn. The piercing inclination can be calculated from the piercing strength, and the piercing strength can be measured using, for example, a small-sized desktop tester [trade name “EZ Test” manufactured by Shimadzu Corporation].

  The measurement of the puncture strength is performed by sandwiching the composite retardation plate between two sample tables having a circular hole with a diameter of 15 mm or less through which the piercing jig can pass. The piercing jig is preferably a cylindrical rod, and is preferably provided with a piercing needle whose tip in contact with the composite retardation plate is spherical or hemispherical. The spherical portion or hemispherical portion at the tip has a diameter of 0.5 mm or more and preferably 5 mm or less. Moreover, it is preferable that the curvature radius is larger than 0 R and smaller than 0.7 R. The piercing speed of the piercing jig is 0.05 cm / sec or more and preferably 0.5 cm / sec or less.

In the measurement of the piercing strength, this test piece is fixed to a jig, and piercing is performed from the normal direction of the main surface of the composite retardation plate, and the strength at one time of tearing is measured. The piercing strength A (kg) obtained at this time, the piercing depth B (mm) before tearing, and the composite retardation plate thickness d (mm) are represented by the following formulas:
E = A / (B × d)
Using this, the piercing inclination per unit film thickness E (kg / mm ² ) is calculated. The piercing inclination of the composite retardation plate is an average value of piercing inclinations E of five or more composite retardation plates manufactured under the same conditions.

  For example, the composite retardation plate 5 is brought into contact with a roll-shaped member such as a transport roll or a winding roll in a process of transporting, winding, etc. the composite retardation plate 5 or an optical laminate including the same. Even when the composite retardation plate is bent by being disposed on the surface of the image display panel having a bent portion, or the like, the first retardation layer 1 and the first retardation layer 1 and the first retardation layer 5 can be obtained according to the present invention. The generation of wrinkles in the second retardation layer 2 can be suppressed.

  The thickness of the composite retardation plate 5 is preferably 1 μm to 100 μm, more preferably 1 μm to 50 μm, and still more preferably 2 to 50 μm, from the viewpoint of thinning.

<First Retardation Layer and Second Retardation Layer>
The first retardation layer 1 and the second retardation layer 2 are not particularly limited as long as they include at least one retardation layer that imparts a predetermined retardation to light, for example, a half wavelength layer It may be an optical compensation layer such as a quarter wavelength layer or a positive C plate, or may be a retardation layer of reverse wavelength dispersion. In particular, in the case of a reverse dispersive retardation layer, the transmission of light is suppressed at any wavelength, and therefore, it is effective as an optical laminate having an antireflection performance. The first retardation layer 1 and the second retardation layer 2 may be formed of only the retardation layer, as long as the first retardation layer 1 and the second retardation layer 2 include at least one retardation layer, or together with the retardation layer. Other layers may be included.
As another layer, a base material layer, an orientation film layer, a protective layer etc. are mentioned, for example. The other layers do not affect the retardation value.

  As a phase difference expression layer, the layer (henceforth a "liquid crystal layer") formed by using a liquid crystal compound, or a stretched film is mentioned. In the first retardation layer 1 and the second retardation layer 2, at least one of the retardation developing layers is preferably a liquid crystal layer from the viewpoint of thinning of the composite retardation plate, and both are liquid crystal layers. Is more preferred. Generally, the retardation layer as a liquid crystal layer is easier to thin than the retardation layer as a stretched film. The thickness of each of the first retardation layer 1 and the second retardation layer 2 is preferably 0.5 μm to 10 μm, and more preferably 0.5 μm to 5 μm. When the first retardation layer and the second retardation layer include other layers (base layer, alignment layer, protective layer, etc.) other than the retardation layer, the total thickness is 0.5 μm to 300 μm. Is preferably 0.5 μm to 150 μm.

  When the composite retardation plate is bent as the thickness of the first retardation layer 1 and the second retardation layer 2 is thinner, the first retardation layer 1 and the second retardation in the bent portion of the composite retardation plate Although wrinkles are easily generated in the layer 2, according to the composite retardation plate of the present invention, even when the first retardation layer 1 and the second retardation layer 2 are as thin as 5 μm or less as described above, the wrinkles are generated. Can be suppressed.

As a combination of the first retardation layer 1 and the second retardation layer 2 in the composite retardation plate of the present invention, for example,
i) combination of a half wave layer and a quarter wave layer,
ii) combination of a half wavelength layer and an optical compensation layer,
iii) combination of quarter wavelength layer and optical compensation layer iv) combination of reverse dispersion quarter wavelength layer and optical compensation layer,
Etc.

  The half-wave layer gives a phase difference of π (= λ / 2) to the electric field vibration direction (polarization plane) of the incident light, and has a function to change the direction (polarization direction) of linear polarization. . In addition, when circularly polarized light is made incident, the rotational direction of circularly polarized light can be reversed.

  The half-wave layer is a layer in which Re (λ), which is an in-plane retardation value at a specific wavelength λ nm, satisfies Re (λ) = λ / 2. It suffices to achieve Re (λ) = λ / 2 at any wavelength in the visible light range, and in particular, it is preferable to achieve it at a wavelength of 550 nm. The in-plane retardation value Re (550) at a wavelength of 550 nm preferably satisfies 210 nm ≦ Re (550) ≦ 300 nm. More preferably, 220 nm ≦ Re (550) ≦ 290 nm is satisfied.

  The retardation value Rth (550), which is the retardation value in the thickness direction of the half-wave layer measured at a wavelength of 550 nm, is preferably -150 to 150 nm, and more preferably -100 to 100 nm.

  The quarter wavelength layer gives a phase difference of π / 2 (= λ / 4) to the electric field vibration direction (polarization plane) of the incident light, and converts linearly polarized light of a specific wavelength into circularly polarized light (or a circle It has a function of converting polarized light into linearly polarized light).

  The 1⁄4 wavelength layer is a layer in which Re (λ) which is an in-plane retardation value at a specific wavelength λ nm satisfies Re (λ) = λ / 4, and is achieved at any wavelength in the visible light range. However, it is preferable to achieve the wavelength of 550 nm. It is preferable that Re (550) which is an in-plane retardation value in wavelength 550nm satisfies 100 nm <= Re (550) <= 160 nm. Furthermore, it is more preferable to satisfy 110 nm ≦ Re (550) ≦ 150 nm.

  It is preferable that it is -120-120 nm, and, as for Rth (550) which is the retardation value of the thickness direction of (lambda) / 4 wavelength layer measured by wavelength 550 nm, it is more preferable that it is -80-80 nm.

  As an optical compensation layer, a positive A plate, a positive C plate, etc. are mentioned, for example. The positive A plate has Nx> Ny, where Nx is the refractive index in the slow axis direction in the plane, Ny is the refractive index in the fast axis direction in the plane, and Nz is the refractive index in the thickness direction. It satisfies the relationship. The positive A plate preferably satisfies the relationship of Nx> Ny ≧ Nz. The positive A plate can also function as a quarter wavelength layer. The positive C plate satisfies the relationship of Nz> Nx ≧ Ny.

Reverse wavelength dispersion is an optical characteristic in which the in-plane retardation value at the short wavelength is smaller than the in-plane retardation value at the long wavelength, and preferably, the following formula (a):
Re (450) ≦ Re (550) ≦ Re (650) (a)
To meet Re (λ) represents an in-plane retardation value for light of wavelength λ nm.

  The optical properties of the retardation layer can be adjusted by the alignment state of the liquid crystal compound constituting the retardation expression layer, or the stretching method of the stretched film constituting the retardation expression layer. By appropriately adjusting the optical properties of the retardation layer, the composite retardation plate 5 and the polarizing plate can be laminated to obtain an optical laminate having an antireflection performance. The optical laminate as referred to in the present specification is formed by laminating a polarizing plate and the composite retardation plate 5, and the composite retardation plate 5 is oriented in such a manner that the first retardation layer 1 is positioned on the polarizing plate side. It is assumed that the Even when the same composite retardation plate 5 is used, when the direction of lamination of the composite retardation plate 5 is reversed, the optical characteristics of the optical laminate are usually different.

(Retardation layer formed of liquid crystal layer)
The case where the phase difference developing layer is a liquid crystal layer will be described. FIG. 2 is a schematic cross-sectional view schematically showing an example of a retardation layer including a retardation expression layer which is a liquid crystal layer and other layers. As shown in FIG. 2, in the retardation layer 30, a base material layer 31, an alignment layer 32, and a retardation expression layer 33 which is a liquid crystal layer are laminated in this order. The phase difference layer is not limited to the phase difference layer 30 shown in FIG. 2 as long as the phase difference layer is a configuration including the phase difference expressing layer 33 which is a liquid crystal layer, and the base material layer 31 is peeled off from the phase difference layer 30 It may be configured to include only the layer 32 and the phase difference developing layer 33 which is a liquid crystal layer, or the base layer 31 and the alignment layer 32 may be peeled from the phase difference plate 30 and only the phase difference developing layer 33 which is a liquid crystal layer. May be configured as follows. From the viewpoint of thinning, the retardation layer preferably has a configuration in which the base material layer 31 is peeled off, and more preferably a configuration in which only the retardation expression layer 33 which is a liquid crystal layer is formed. The base material layer 31 has a function as a support layer for supporting the alignment layer 32 formed on the base material layer 31 and the phase difference developing layer 33. The base layer 31 is preferably a film formed of a resin material.

  As a resin material, for example, a resin material excellent in transparency, mechanical strength, thermal stability, stretchability, and the like is used. Specifically, polyolefin resins such as polyethylene and polypropylene; cyclic polyolefin resins such as norbornene polymer; polyester resins such as polyethylene terephthalate and polyethylene naphthalate; (meth) acrylic acid, methyl poly (meth) acrylate and the like (Meth) acrylic acid based resins; cellulose ester based resins such as triacetyl cellulose, diacetyl cellulose and cellulose acetate propionate; vinyl alcohol based resins such as polyvinyl alcohol and polyvinyl acetate; polycarbonate based resins; polystyrene based resins Arylate resins; Polysulfone resins; Polyethersulfone resins; Polyamide resins; Polyimide resins; Polyether ketone resins; Polyphenylene sulfide resins; Ren'okishido resins, and mixtures thereof, may be mentioned copolymer and the like. Among these resins, it is preferable to use any one or a mixture of a cyclic polyolefin resin, a polyester resin, a cellulose ester resin, and a (meth) acrylic acid resin. In addition, said "(meth) acrylic acid" means "at least 1 sort (s) of acrylic acid and methacrylic acid."

  The base material layer 31 may be a single layer obtained by mixing one or more of the above-described resins, or may have a multilayer structure of two or more layers. In the case of having a multilayer structure, the resins forming each layer may be the same or different.

  Optional additives may be added to the resin material forming the resin film. As an additive, an ultraviolet absorber, an antioxidant, a lubricant, a plasticizer, a mold release agent, a coloring agent, a flame retardant, a nucleating agent, an antistatic agent, a pigment, a coloring agent etc. are mentioned, for example.

  The thickness of the base layer 31 is not particularly limited, but in general, it is preferably 5 to 200 μm, more preferably 10 to 200 μm, and 10 to 150 μm from the viewpoint of workability such as strength and handleability. It is further preferred that

  In order to improve the adhesion between the base material layer 31 and the alignment layer 32, at least the surface of the base material layer 31 on the side where the alignment layer 32 is formed may be subjected to corona treatment, plasma treatment, flame treatment, etc. A primer layer or the like may be formed. In addition, when peeling the base material layer 31 or the base material layer 31 and the orientation layer 32 and setting it as a retardation layer, peeling can be made easy by adjusting the adhesive force in a peeling interface.

  The alignment layer 32 has an alignment regulating force that causes the liquid crystal compound contained in the retardation expression layer 33 which is a liquid crystal layer formed on the alignment layer 32 to be aligned in a desired direction. Examples of the alignment layer 32 include an alignment polymer layer formed of an alignment polymer, a photoalignment polymer layer formed of a photoalignment polymer, and a glue alignment layer having a concavo-convex pattern and a plurality of grooves (grooves) on the layer surface. be able to. The thickness of the alignment layer 32 is usually 0.01 to 10 μm, preferably 0.01 to 5 μm.

  The oriented polymer layer can be formed by applying a composition in which the oriented polymer is dissolved in a solvent to the substrate layer 31 to remove the solvent, and rubbing as necessary. In this case, the alignment control force can be arbitrarily adjusted by the surface state of the alignment polymer and the rubbing condition in the alignment polymer layer formed of the alignment polymer.

  The photoalignable polymer layer can be formed by applying a composition containing a polymer or monomer having a photoreactive group and a solvent to the substrate layer 31 and irradiating polarized light. In this case, in the photoalignable polymer layer, the alignment regulating force can be arbitrarily adjusted by the irradiation condition of polarized light to the photoalignable polymer and the like.

  The glue alignment layer is formed, for example, by a method of forming a concavo-convex pattern by performing exposure, development, etc. through a mask for exposure having a pattern-shaped slit on the surface of a photosensitive polyimide film, a plate-like master having grooves on the surface, A method of forming an uncured layer of energy beam curable resin, transferring this layer to the substrate layer 31 and curing it, forming an uncured layer of an active energy beam curable resin on the substrate layer 31, The layer can be formed by a method of forming unevenness by pressing a roll-like master having unevenness, and curing.

  The phase difference developing layer 33 which is a liquid crystal layer is not particularly limited as long as it imparts a predetermined phase difference to light, and, for example, the phase difference developing layer for 1⁄2 wavelength layer, the position for 1⁄4 wavelength layer What can function as a phase difference expression layer for optical compensation layers, such as a phase difference expression layer and positive C plate, and a phase difference expression layer for reverse wavelength dispersion quarter wavelength layers, can be mentioned.

The phase difference developing layer 33 which is a liquid crystal layer can be formed using a known liquid crystal compound.
The type of liquid crystal compound is not particularly limited, and rod-like liquid crystal compounds, discotic liquid crystal compounds, and mixtures thereof can be used. The liquid crystal compound may be a polymer liquid crystal compound, a polymerizable liquid crystal compound, or a mixture of these. As liquid crystal compounds, for example, JP-A-11-513019, JP-A-2005-289980, JP-A-2007-108732, JP-A-2010-244038, JP-A-2010-31223 and JP-A-2010-312223 are disclosed. Liquid crystal compounds described in 2010-270108, JP-A-2011-6360, JP-A-2011-207765, JP-A-2016-81035, International Publication No. 2017/043438 and JP-A-2011-207765 Can be mentioned.

  For example, in the case of using a polymerizable liquid crystal compound, a composition containing a polymerizable liquid crystal compound is coated on the alignment layer 32 to form a coating film, and the coating film is cured to form a phase difference developing layer 33. Can be formed. The thickness of the phase difference developing layer 33 is preferably 0.5 μm to 10 μm, and more preferably 0.5 to 5 μm.

  The composition containing the polymerizable liquid crystal compound may contain, in addition to the liquid crystal compound, a polymerization initiator, a polymerizable monomer, a surfactant, a solvent, an adhesion improver, a plasticizer, an alignment agent, and the like. Examples of the method of applying the composition containing the polymerizable liquid crystal compound include known methods such as a die coating method. As a method of curing a composition containing a polymerizable compound, known methods such as irradiation with active energy rays (for example, ultraviolet rays) may be mentioned.

(Retardation plate provided with stretched film as retardation expression layer)
The case where the phase difference developing layer is a stretched film will be described. A stretched film is usually obtained by stretching a substrate. As a method of stretching the substrate, for example, a roll (rolling body) in which the substrate is wound into a roll is prepared, and the substrate is continuously unwound and unwound from the wound body. The substrate is transported to the furnace. The setting temperature of the heating furnace is in the range of around the glass transition temperature of the substrate (° C) to [glass transition temperature + 100] (° C), preferably around the glass transition temperature (° C) to [glass transition temperature + 50] (° C) Range of In the heating furnace, when stretching in the direction of movement of the base material or in the direction perpendicular to the direction of movement, the transport direction and tension are adjusted, and an arbitrary angle is inclined to perform uniaxial or biaxial thermal stretching processing. Do. The magnification of stretching is usually 1.1 to 6 times, preferably 1.1 to 3.5 times.

  Moreover, as a method of extending | stretching diagonally, if an orientation axis | shaft can be continuously made to incline to a desired angle, it will not be specifically limited, A well-known extending | stretching method is employable. As such a stretching method, for example, the methods described in JP-A-50-83482 and JP-A-2-113920 can be mentioned. When the film is provided with retardation by stretching, the thickness after stretching is determined by the thickness before stretching and the stretching ratio.

  The substrate is usually a transparent substrate. The term "transparent substrate" means a substrate having transparency capable of transmitting light, particularly visible light, and transparency means that the transmittance for light having a wavelength of 380 to 780 nm is 80% or more. Say. As a specific transparent base material, a translucent resin base material is mentioned. As a resin which comprises a translucent resin base material, Polyolefins, such as polyethylene and a polypropylene; Cyclic olefin type resins, such as a norbornene-type polymer; Polyvinyl alcohol; Polyethylene terephthalate; Poly methacrylate; Poly acrylate; Triacetyl cellulose, Cellulose esters such as diacetyl cellulose and cellulose acetate propionate; polyethylene naphthalate; polycarbonate; polysulfone; polyethersulfone; polyethersulfone; polyether ketone; polyphenylene sulfide and polyphenylene oxide. From the viewpoint of availability and transparency, polyethylene terephthalate, polymethacrylic acid ester, cellulose ester, cyclic olefin resin or polycarbonate is preferable.

  Cellulose ester is obtained by esterifying some or all of the hydroxyl groups contained in cellulose and can be easily obtained from the market. Also, cellulose ester base materials can be easily obtained from the market. Commercially available cellulose ester substrates include, for example, “Fujitak (registered trademark) film” (Fuji Film Co., Ltd.); “KC8UX2M”, “KC8UY” and “KC4UY” (Konica Minolta Opto Co., Ltd.), etc. .

  Polymethacrylic acid esters and polyacrylic acid esters (hereinafter, polymethacrylic acid esters and polyacrylic acid esters may be collectively referred to as (meth) acrylic resins) are readily available from the market.

  Examples of (meth) acrylic resins include homopolymers of methacrylic acid alkyl esters or acrylic acid alkyl esters, and copolymers of methacrylic acid alkyl esters and acrylic acid alkyl esters. Specific examples of the methacrylic acid alkyl ester include methyl methacrylate, ethyl methacrylate and propyl methacrylate, and specific examples of the acrylic acid alkyl ester include methyl acrylate, ethyl acrylate and propyl acrylate. As such (meth) acrylic resins, those commercially available as general-purpose (meth) acrylic resins can be used. As the (meth) acrylic resin, one called an impact resistant (meth) acrylic resin may be used.

  It is also preferable to include rubber particles in the (meth) acrylic resin for further mechanical strength improvement. The rubber particles are preferably acrylic. Here, the acrylic rubber particles have a rubber elasticity obtained by polymerizing an acrylic monomer having an acrylic acid alkyl ester such as butyl acrylate or 2-ethylhexyl acrylate as a main component in the presence of a polyfunctional monomer. It is a particle. The acrylic rubber particles may be formed of a single layer of particles having such rubber elasticity, or may be a multilayer structure having at least one rubber elastic layer. As the acrylic rubber particles having a multilayer structure, those having the above-described particles having rubber elasticity as a core and the periphery thereof covered with a hard methacrylic acid alkyl ester type polymer, a hard methacrylic acid alkyl ester type polymer A core is covered with an acrylic polymer having rubber elasticity as described above, and a hard core is covered with a rubber elastic acrylic polymer, and a hard methacrylic acid alkyl ester is further wrapped around the core. What was covered by a system polymer etc. are mentioned. The rubber particles formed of the elastic layer usually have an average diameter in the range of about 50 to 400 nm.

  The content of the rubber particles in the (meth) acrylic resin is usually about 5 to 50 parts by mass per 100 parts by mass of the (meth) acrylic resin. The (meth) acrylic resin and the acrylic rubber particles are commercially available in the state of mixing them, so that commercially available products can be used. As an example of the commercial item of (meth) acrylic resin which blended acrylic rubber particles, "HT55X", "Technoloi S001" etc. which are sold from Sumitomo Chemical Co., Ltd. are mentioned. "Technalloy S001" is sold in the form of a film.

  Cyclic olefin resins are readily available from the market. As commercially available cyclic olefin resins, "Topas" (registered trademark) (Ticona (Germany)), "Arton" (registered trademark) (JSR Corporation), "ZEONOR" (registered trademark) (Japan) Zeon Co., Ltd., "ZEONEX" (registered trademark) (Nippon Zeon Co., Ltd.) and "APEL" (registered trademark) (Mitsui Chemical Co., Ltd.) can be mentioned. Such a cyclic olefin resin can be formed into a film by a known means such as, for example, a solvent casting method, a melt extrusion method, and the like to be used as a substrate. Moreover, the cyclic olefin resin base material marketed can also be used. As a commercially available cyclic olefin resin base material, "ESSINA" (registered trademark) [Sekisui Chemical Co., Ltd.], "SCA 40" (registered trademark) [Sekisui Chemical Co., Ltd.], "ZEONOR Film" (registered trademark) And the like) and “Arton Film” (registered trademark) [JSR Corporation].

  When the cyclic olefin resin is a copolymer of cyclic olefin and an aromatic compound having a chain olefin or a vinyl group, the content ratio of structural units derived from cyclic olefin is the total structural unit of the copolymer. On the other hand, it is usually at most 50 mol%, preferably in the range of 15 to 50 mol%. The linear olefins include ethylene and propylene, and the aromatic compounds having a vinyl group include styrene, α-methylstyrene and alkyl-substituted styrene. When the cyclic olefin resin is a ternary copolymer of a cyclic olefin, a chain olefin, and an aromatic compound having a vinyl group, the content ratio of structural units derived from the chain olefin is that of the copolymer The content of structural units derived from an aromatic compound having a vinyl group is usually 5 to 80 mol% based on the total structural units, and is usually 5 to 80 mol% based on the total structural units of the copolymer It is. Such terpolymers have the advantage of being able to use relatively low amounts of expensive cyclic olefins in their preparation.

<First adhesive layer>
The first adhesive layer 4, as long as it can achieve the inclination ^6kg / mm ^{2 ~15kg} / mm 2 piercing per unit thickness of the composite retardation plate 5 is not particularly limited, for example, pressure-sensitive adhesive And water-based adhesives, active energy ray-curable adhesives, and combinations thereof. Among them, the first adhesive layer 4, by a cured layer of the active energy ray-curable adhesive, easily obtain a composite retardation plate 5 tilt ^6kg / mm ^{2 ~15kg} / mm 2 piercing. The thickness of the first adhesive layer 4 is preferably 0.1 μm to 50 μm, more preferably 0.1 μm to 10 μm, and still more preferably 0.5 μm to 5 μm. As used herein, the term "first adhesive layer" includes not only an adhesive layer composed of an adhesive but also an adhesive layer composed of an adhesive.

  In general, as a pressure-sensitive adhesive, an acrylic monomer mixture mainly composed of (meth) acrylic acid ester and containing a small amount of (meth) acrylic monomer having a functional group is radically polymerized in the presence of a polymerization initiator. An acrylic pressure-sensitive adhesive which is obtained and contains an acrylic resin having a glass transition temperature Tg of 0 ° C. or less and a crosslinking agent is preferably used.

  It is preferable that the acrylic resin which comprises an acrylic adhesive has the weight average molecular weights Mw of standard polystyrene conversion by gel permeation chromatography (GPC) in the range of 1 million-2 million. When the weight average molecular weight Mw is 1,000,000 or more, the adhesiveness under high temperature and high humidity is improved, and the possibility of floating or peeling between the glass substrate constituting the liquid crystal cell and the pressure sensitive adhesive layer is small. And reworkability tends to be improved. Also, if the weight average molecular weight Mw of the acrylic resin is 2,000,000 or less, the adhesive layer fluctuates following the dimensional change of the polarizing plate, so that the light leakage and color of the display It is preferable because unevenness tends to be suppressed. Furthermore, it is preferable that the molecular weight distribution represented by ratio Mw / Mn of weight average molecular weight Mw and number average molecular weight Mn exists in the range of 3-7.

  The acrylic resin contained in the acrylic pressure sensitive adhesive can be composed of only those having a relatively high molecular weight as described above, but can also be composed of a mixture with a different acrylic resin. As an example of the acrylic resin which can be mixed and used, the structural unit derived from the (meth) acrylic acid ester represented by the above formula (I) is used as a main component, and the weight average molecular weight is 50,000 to 300,000. There is something in the range.

  The acrylic resin thus obtained is blended with a crosslinking agent to be used as a pressure sensitive adhesive. The crosslinking agent is a compound having in the molecule at least two functional groups capable of undergoing a crosslinking reaction with a structural unit derived from a monomer having a polar functional group in an acrylic resin, for example, an isocyanate compound, an epoxy compound, Examples include metal chelate compounds and aziridine compounds.

  As a method of forming a pressure-sensitive adhesive layer on the present optical film, for example, a release film is used as a substrate, the above-mentioned pressure-sensitive adhesive composition is applied to form a pressure-sensitive adhesive layer, and the obtained pressure-sensitive adhesive layer is A method of transferring to the surface of the film, a method of directly applying the above-mentioned pressure-sensitive adhesive composition to the surface of the present optical film to form a pressure-sensitive adhesive layer, and the like are adopted. Moreover, after forming an adhesive layer on the peeling film of 1 sheet, another release film can be further bonded on the adhesive layer, and it can also be set as a double-sided separator type | mold adhesive sheet. Such a double-sided separator type pressure-sensitive adhesive sheet peels off the release film on one side at a necessary time, and is bonded onto the present optical film. Examples of commercially available double-sided separator-type pressure-sensitive adhesive sheets include non-carrier pressure-sensitive adhesive films and non-carrier pressure-sensitive adhesive sheets sold by Lintec Corporation and Nitto Denko Corporation.

  As a water-based adhesive, for example, using a polyvinyl alcohol resin or urethane resin as a main component, and a composition containing a crosslinking agent or a curable compound such as an isocyanate compound or an epoxy compound to improve adhesion It is common to do.

  When a polyvinyl alcohol-based resin is used as the main component of the aqueous adhesive, in addition to partially saponified polyvinyl alcohol and completely saponified polyvinyl alcohol, carboxyl group modified polyvinyl alcohol, acetoacetyl group modified polyvinyl alcohol, methylol group modified polyvinyl alcohol, and amino A modified polyvinyl alcohol resin such as a group modified polyvinyl alcohol may be used. An aqueous solution of such a polyvinyl alcohol-based resin is used as a water-based adhesive, and the concentration of the polyvinyl alcohol-based resin in the water-based adhesive is usually 1 to 10 parts by mass, preferably 100 parts by mass of water. 1 to 5 parts by mass.

  In the water-based adhesive composed of an aqueous solution of a polyvinyl alcohol-based resin, in order to improve the adhesiveness as described above, curing such as a polyvalent aldehyde, a water-soluble epoxy resin, a melamine-based compound, a zirconia-based compound, and a zinc compound Compounds can be formulated. As an example of the water-soluble epoxy resin, it is possible to use an aqueous solution obtained by reacting epichlorohydrin with a polyamide polyamine obtained by the reaction of a polyalkylene polyamine such as diethylenetriamine or triethylenetetramine and a dicarboxylic acid such as adipic acid. Polyamide epoxy resin. As a commercial product of such polyamide epoxy resin, "Sumirez Resin 650" and "Sumirez Resin 675" sold by Sumika Chemtex Co., Ltd., "WS-525" sold by Japan PMC Co., Ltd., etc. There is. When mix | blending a water-soluble epoxy resin, the addition amount is about 1-100 mass parts normally with respect to 100 mass parts of polyvinyl alcohol-type resin, Preferably it is 1-50 mass parts.

  When a urethane resin is used as the main component of the water-based adhesive, it is effective to use a polyester ionomer urethane resin as the main component of the water-based adhesive. The polyester-based ionomer-type urethane resin as referred to herein is a urethane resin having a polyester skeleton, into which a small amount of ionic component (hydrophilic component) is introduced. Such an ionomer-type urethane resin can be used as a water-based adhesive because it is directly emulsified in water without using an emulsifier to form an emulsion. When using a polyester-based ionomer-type urethane resin, it is effective to blend a water-soluble epoxy compound as a crosslinking agent. The use of a polyester-based ionomer-type urethane resin as an adhesive for polarizing plates is described, for example, in JP-A-2005-70140 and JP-A-2005-208456.

  Each of these components constituting the water-based adhesive is usually used in the state of being dissolved in water. The water-based adhesive is applied onto a suitable substrate and dried to obtain an adhesive layer. Components that do not dissolve in water may be in the state of being dispersed in the system.

  As a method of forming the said adhesive layer on this optical film, the method of apply | coating said adhesive composition directly on this optical film surface, and forming an adhesive layer etc. are mentioned.

  Also, for example, after the obtained water-based adhesive is injected between the polarizing plate and the present optical film, the water is evaporated by heating and the thermal crosslinking reaction is advanced to give sufficient adhesiveness to both of them. Can.

The active energy ray-curable adhesive is to cure upon exposure to active energy rays, to obtain a composite retardation plate 5 tilt 6kg ^/ mm ² ~15kg / mm 2 piercing per unit thickness It is not limited as long as it can be done. For example, a cationically polymerizable active energy ray-curable adhesive containing an epoxy compound and a cationic polymerization initiator, a radically polymerizable active energy ray-curable adhesive containing an acrylic curing component and a radical polymerization initiator, an epoxy compound An active energy ray-curable adhesive comprising both a cationically polymerizable curing component such as: and a radically polymerizable curing component such as an acrylic compound, and having incorporated therein a cationic polymerization initiator and a radical polymerization initiator And an electron beam curable adhesive which is cured by irradiating an active energy ray curable adhesive containing no initiator with an electron beam. Preferably, it is a radically polymerizable active energy ray-curable adhesive containing an acrylic curing component and a radical polymerization initiator. Further, a cationically polymerizable active energy ray-curable adhesive containing an epoxy compound and a cationic polymerization initiator which can be used substantially without a solvent is preferable.

  A cationically polymerizable epoxy compound that is liquid at room temperature, has adequate fluidity without the presence of a solvent, and provides suitable cured adhesive strength, and a cationic compound suitable therefor An active energy ray-curable adhesive compounded with a polymerization initiator eliminates the drying equipment usually required in the process of bonding the first retardation layer and the second retardation layer in the production equipment of a composite retardation plate. Can. In addition, irradiation with an appropriate dose of active energy can accelerate the curing rate and improve the production rate.

  The epoxy compound used for such an adhesive is, for example, a glycidyl ether compound of an aromatic compound or a chain compound having a hydroxyl group, a glycidyl amination product of a compound having an amino group, a chain compound having a C—C double bond Or a cycloaliphatic epoxy compound in which a glycidyloxy group or an epoxyethyl group is bonded directly or via an alkylene to a saturated carbon ring, or an epoxy group is directly bonded to a saturated carbon ring it can. These epoxy compounds may be used alone or in combination of two or more different ones. Among them, alicyclic epoxy compounds are preferably used because they are excellent in cationic polymerization.

  The glycidyl etherification thing of the aromatic compound which has a hydroxyl group, or a chain compound can be manufactured by the method of carrying out addition condensation of the epichlorohydrin to the hydroxyl group of these aromatic compounds or a chain compound under basic conditions, for example. Such glycidyl ethers of hydroxyl-containing aromatic compounds or chain compounds include diglycidyl ethers of bisphenols, polyaromatic ring epoxy resins, diglycidyl ethers of alkylene glycols or polyalkylene glycols, and the like. .

  As diglycidyl ethers of bisphenols, for example, glycidyl ether of bisphenol A and its oligomer, glycidyl ether of bisphenol F and its oligomer, 3,3 ', 5,5'-tetramethyl-4,4'- Examples thereof include glycidyl ether of biphenol and its oligomer.

  As polyaromatic ring epoxy resin, for example, glycidyl ether of phenol novolak resin, glycidyl ether of cresol novolak resin, glycidyl ether of phenol aralkyl resin, glycidyl ether of naphthol aralkyl resin, glycidyl ether of phenol dicyclopentadiene resin And the like. Further, glycidyl ethers of trisphenols and their oligomers and the like also belong to polyaromatic ring epoxy resins.

  Examples of diglycidyl ethers of alkylene glycols or polyalkylene glycols include glycidyl ether of ethylene glycol, glycidyl ether of diethylene glycol, glycidyl ether of 1,4-butanediol, glycidyl ether of 1,6-hexanediol, etc. It can be mentioned.

  The glycidyl amination thing of the compound which has an amino group can be manufactured, for example by the method of carrying out addition condensation of the epichlorohydrin to basic compound of the said compound under basic conditions. The compound having an amino group may simultaneously have a hydroxyl group. Such glycidyl amino compounds of compounds having an amino group include glycidyl amino compounds of 1,3-phenylene diamine and oligomers thereof, glycidyl amino compounds of 1,4-phenylene diamine and oligomers thereof, 3-aminophenol Glycidyl amination and glycidyl esterification product of glycidyl aglycinate and its oligomer, glycidyl amination and glycidyl esterification product of 4-aminophenol and its oligomer, and the like are included.

  Epoxides of linear compounds having C—C double bonds can be prepared by epoxidation of the C—C double bonds of the linear compounds with a peroxide under basic conditions. Chain compounds having a C—C double bond include butadiene, polybutadiene, isoprene, pentadiene, hexadiene and the like. In addition, terpenes having a double bond can also be used as an epoxidation raw material, and as non-cyclic monoterpenes, there are linalool and the like. The peroxide used for epoxidation can be, for example, hydrogen peroxide, peracetic acid, tert-butyl hydroperoxide and the like.

  An alicyclic epoxy compound in which a glycidyl oxy group or an epoxyethyl group is bonded to a saturated carbon ring directly or through an alkylene is an aromatic ring of a hydroxyl group-containing aromatic compound represented by bisphenols listed above. The glycidyl ether compound of the hydrogenated polyhydroxy compound obtained by hydrogenation, the glycidyl ether compound of the cycloalkane compound which has a hydroxyl group, the epoxy compound of the cycloalkane compound which has a vinyl group, etc. can be used.

  The epoxy compounds described above are readily commercially available. For example, the “jER” series sold by Mitsubishi Chemical Corporation under the trade names and “Epiclon” sold by DIC Corporation are available. "Epototh (registered trademark)" sold by Toto Kasei Co., Ltd., "Adecaresin (registered trademark)" sold by ADEKA Co., Ltd., "Denacol (registered trademark) sold by Nagase ChemteX Co., Ltd." ), “Dow Epoxy” sold by Dow Chemical Company, “Tepic (registered trademark)” sold by Nissan Chemical Industries, Ltd., and the like.

  On the other hand, an alicyclic epoxy compound in which an epoxy group is directly bonded to a saturated carbon ring is, for example, basic to a C-C double bond of a non-aromatic cyclic compound having a C-C double bond in the ring It can be produced by the method of epoxidation using peroxide under the conditions. As a non-aromatic cyclic compound having a C—C double bond in the ring, for example, a compound having a cyclopentene ring, a compound having a cyclohexene ring, at least two carbon atoms bonded to a cyclopentene ring or a cyclohexene ring Polycyclic compounds forming an additional ring and the like can be mentioned. A non-aromatic cyclic compound having a C—C double bond in the ring may have another C—C double bond outside the ring. Examples of non-aromatic cyclic compounds having a C—C double bond in the ring include cyclohexene, 4-vinylcyclohexene, single ring monoterpenes limonene and α-pinene.

  In an alicyclic epoxy compound in which an epoxy group is directly bonded to a saturated carbocyclic ring, an alicyclic structure having an epoxy group directly bonded to a ring as described above is intramolecularly via a suitable linking group It may be a compound formed at least two. The linking group as referred to herein includes, for example, an ester bond, an ether bond, an alkylene bond and the like.

  Specific examples of the alicyclic epoxy compound in which the epoxy group is directly bonded to a saturated carbon ring are as follows.

3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexane carboxylate,
1,2-epoxy-4-vinylcyclohexane,
1,2-epoxy-4-epoxyethylcyclohexane,
1,2-epoxy-1-methyl-4- (1-methylepoxyethyl) cyclohexane, 3,4-epoxycyclohexylmethyl (meth) acrylate,
An adduct of 2,2-bis (hydroxymethyl) -1-butanol with 4-epoxyethyl-1,2-epoxycyclohexane,
Ethylene bis (3,4-epoxycyclohexane carboxylate),
Oxydiethylene bis (3,4-epoxycyclohexanecarboxylate),
1,4-cyclohexanedimethyl bis (3,4-epoxycyclohexanecarboxylate),
3- (3,4-epoxycyclohexylmethoxycarbonyl) propyl 3,4-epoxycyclohexane carboxylate and the like.

  Commercially available products can also be easily obtained from the alicyclic epoxy compounds in which an epoxy group is directly bonded to the saturated carbon ring described above, and for example, they are sold by Daicel Corporation under the respective trade names. These include the "Cerrocide" series and "Cyclomer", and the "Syracure UVR" series sold by Dow Chemical.

  The curable adhesive containing an epoxy compound may further contain an active energy ray-curable compound other than the epoxy compound. Examples of the active energy ray curable compound other than the epoxy compound include, for example, an oxetane compound and an acrylic compound. Among them, it is preferable to use an oxetane compound in combination since there is a possibility of accelerating the curing rate in cationic polymerization.

  The oxetane compound is a compound having a four-membered ring ether in the molecule, and examples thereof include the following.

1,4-bis [(3-ethyloxetan-3-yl) methoxymethyl] benzene,
3-ethyl-3- (2-ethylhexyl oxymethyl) oxetane,
Bis (3-ethyl-3-oxetanylmethyl) ether,
3-ethyl-3- (phenoxymethyl) oxetane,
3-ethyl-3- (cyclohexyloxymethyl) oxetane,
Phenolic novolac oxetane,
Xylylene bis oxetane,
1,3-bis [(3-ethyl oxetan-3-yl) methoxy] benzene and the like.

  Commercially available oxetane compounds are also easily obtainable, and for example, “Aron Oxetane (registered trademark)” series sold by Toagosei Co., Ltd. under the respective trade names and commercially available from Ube Industries, Ltd. And the “ETERNACOLL (registered trademark)” series.

  As a curable compound including an epoxy compound and an oxetane compound, it is preferable to use one which has not been diluted with an organic solvent or the like in order to make the adhesive compounded with such a compound no solvent. In addition, other components that constitute the adhesive, and small amounts of components including cationic polymerization initiators and sensitizers described later are also removed and dried from the organic solvent than those dissolved in the organic solvent. It is preferred to use a powder or liquid of the compound alone.

  The cationic polymerization initiator is a compound which is irradiated with active energy rays such as ultraviolet rays to generate cationic species. It may be any one that gives the adhesive strength and curing speed required for the compounded adhesive, but, for example, aromatic diazonium salts; onium salts such as aromatic iodonium salts and aromatic sulfonium salts; iron-arene complexes Etc. These cationic polymerization initiators may be used alone or in combination of two or more different ones.

Examples of the aromatic diazonium salt include the following.
Benzenediazonium hexafluoroantimonate,
Benzenediazonium hexafluorophosphate,
Benzene diazonium hexafluoroborate etc.

Examples of the aromatic iodonium salt include the following.
Diphenyliodonium tetrakis (pentafluorophenyl) borate,
Diphenyliodonium hexafluorophosphate,
Diphenyliodonium hexafluoroantimonate,
Bis (4-nonylphenyl) iodonium hexafluorophosphate and the like.

Examples of the aromatic sulfonium salt include the following.
Triphenylsulfonium hexafluorophosphate,
Triphenylsulfonium hexafluoroantimonate,
Triphenylsulfonium tetrakis (pentafluorophenyl) borate,
Diphenyl (4-phenylthiophenyl) sulfonium hexafluoroantimonate,
4,4'-bis (diphenylsulfonio) diphenyl sulfide bishexafluorophosphate,
4,4'-bis [di (β-hydroxyethoxyphenyl) sulfonio] diphenyl sulfide bishexafluoroantimonate,
4,4'-bis [di (β-hydroxyethoxyphenyl) sulfonio] diphenyl sulfide bishexafluorophosphate,
7- [di (p-toluyl) sulfonio] -2-isopropylthioxanthone hexafluoroantimonate,
7- [di (p-toluyl) sulfonio] -2-isopropylthioxanthone tetrakis (pentafluorophenyl) borate
4-phenylcarbonyl-4'-diphenylsulfonio diphenyl sulfide hexafluorophosphate,
4- (p-tert-butylphenylcarbonyl) -4′-diphenylsulfonio diphenyl sulfide hexafluoroantimonate,
4- (p-tert-butylphenylcarbonyl) -4'-di (p-toluyl) sulfonio-diphenyl sulfide tetrakis (pentafluorophenyl) borate and the like.

Examples of the iron-arene complex include the following.
Xylene-cyclopentadienyliron (II) hexafluoroantimonate,
Cumene-cyclopentadienyliron (II) hexafluorophosphate, xylene-cyclopentadienyliron (II) tris (trifluoromethylsulfonyl) methanide and the like.

  Among the cationic polymerization initiators, the aromatic sulfonium salt has an ultraviolet absorbing property even in a wavelength range of 300 nm or more, so it is excellent in curability and can give an adhesive layer having good mechanical strength and adhesive strength. Therefore, it is preferably used.

  Commercially available cationic polymerization initiators are also readily available, for example, “Kayarad (registered trademark)” series sold by Nippon Kayaku Co., Ltd. under the respective trade names, and sold by Dow Chemical Co. "Cyracure UVI" series, photo acid generator "CPI" series sold by San-Apro, photo acid generator "TAZ", "BBI" and "DTS" sold by Midori Chemical Co., Ltd. And the “Adeka Optomer” series sold by ADEKA Co., Ltd., and “RHODORSIL (registered trademark)” sold by Rhodia.

  In the active energy ray-curable adhesive, the cationic polymerization initiator is usually blended in a ratio of 0.5 to 20 parts by mass, preferably 1 to 15 with respect to 100 parts by mass of the total amount of the active energy ray-curable adhesive. It is a mass part. If the amount is too small, curing may be insufficient and the mechanical strength and adhesive strength of the adhesive layer may be reduced. When the amount is too large, the hygroscopicity of the adhesive layer may be increased by the increase of the ionic substance in the adhesive layer, and the durability performance of the obtained polarizing plate may be lowered.

  When the active energy ray-curable adhesive is used in the electron beam curing type, it is not particularly necessary to include a photopolymerization initiator in the composition, but in the case of using the ultraviolet curing type, a photo radical generator is used Is preferred. Examples of the photo radical generator include a hydrogen abstraction type photo radical generator and a cleavage type photo radical generator.

  Examples of hydrogen abstraction type photoradical generators include 1-methylnaphthalene, 2-methylnaphthalene, 1-fluoronaphthalene, 1-chloronaphthalene, 2-chloronaphthalene, 1-bromonaphthalene, 2-bromonaphthalene, 1-iodonaphthalene Naphthalene derivatives such as 2-iodonaphthalene, 1-naphthol, 2-naphthol, 1-methoxynaphthalene, 2-methoxynaphthalene, 1,4-dicyanonaphthalene, anthracene, 1,2-benzanthracene, 9,10-dichloroanthracene Anthracene derivatives such as 9,10-dibromoanthracene, 9,10-diphenylanthracene, 9-cyanoanthracene, 9,10-dicyanoanthracene, 2,6,9,10-tetracyanoanthracene, pyrene derivatives, carbazole 9-methylcarbazole, 9-phenylcarbazole, 9-prop-2-ynyl-9H-carbazole, 9-propyl-9H-carbazole, 9-vinylcarbazole, 9H-carbazole-9-ethanol, 9-methyl-3-nitro -9H-carbazole, 9-methyl-3,6-dinitro-9H-carbazole, 9-octanoylcarbazole, 9-carbazolemethanol, 9-carbazolepropionic acid, 9-carbazolepropionitrile, 9-ethyl-3,6 -Dinitro-9H-carbazole, 9-ethyl-3-nitrocarbazole, 9-ethylcarbazole, 9-isopropylcarbazole, 9- (ethoxycarbonylmethyl) carbazole, 9- (morpholinomethyl) carbazole, 9-acetylcarbazole, 9- Allyl Rubazole, 9-benzyl-9H-carbazole, 9-carbazoleacetic acid, 9- (2-nitrophenyl) carbazole, 9- (4-methoxyphenyl) carbazole, 9- (1-ethoxy-2-methyl-propyl) -9H -Carbazole, 3-nitrocarbazole, 4-hydroxycarbazole, 3,6-dinitro-9H-carbazole, 3,6-diphenyl-9H-carbazole, 2-hydroxycarbazole, 3,6-diacetyl-9-ethylcarbazole and the like Carbazole derivative, benzophenone, 4-phenylbenzophenone, 4,4'-bis (dimethoxy) benzophenone, 4,4'-bis (dimethylamino) benzophenone, 4,4'-bis (diethylamino) benzophenone, methyl 2-benzoylbenzoate Ester, 2- Benzophenone derivatives such as methylbenzophenone, 3-methylbenzophenone, 4-methylbenzophenone, 3,3'-dimethyl-4-methoxybenzophenone, 2,4,6-trimethylbenzophenone, aromatic carbonyl compounds, [4- (4-methyl) Phenylthio) phenyl] -phenylmethanone, xanthone, thioxanthone, 2-chlorothioxanthone, 4-chlorothioxanthone, 2-isopropyl thioxanthone, 4-isopropyl thioxanthone, 2,4-dimethyl thioxanthone, 2,4-diethyl thioxanthone, 1- Thioxanthone derivatives such as chloro-4-propoxythioxanthone and coumarin derivatives can be mentioned.

  The cleavage type photoradical generator is a type of photoradical generator in which the compound is cleaved to generate a radical upon irradiation with active energy rays, and specific examples thereof include arylalkyls such as benzoin ether derivatives and acetophenone derivatives. Ketones, oxime ketones, acyl phosphine oxides, S-phenyl thiobenzoate, titanocenes, and derivatives obtained by polymerizing them may be mentioned, but it is not limited thereto. Commercially available cleavage type photoradical generators include 1- (4-dodecylbenzoyl) -1-hydroxy-1-methylethane, 1- (4-isopropylbenzoyl) -1-hydroxy-1-methylethane, 1-benzoyl -1-hydroxy-1-methyl ethane, 1- [4- (2-hydroxyethoxy) -benzoyl] -1-hydroxy-1-methyl ethane, 1- [4- (acryloyloxyethoxy) -benzoyl] -1-hydroxy- 1-Methylethane, diphenyl ketone, phenyl-1-hydroxy-cyclohexyl ketone, benzyl dimethyl ketal, bis (cyclopentadienyl) -bis (2,6-difluoro-3-pyryl-phenyl) titanium, (η6-isopropylbenzene) -(Η 5-cyclopentadienyl) -iron (II) hexaf Fluorophosphate, trimethylbenzoyl diphenyl phosphine oxide, bis (2,6-dimethoxy-benzoyl)-(2,4,4-trimethyl-pentyl) -phosphine oxide, bis (2,4,6-trimethyl benzoyl) -2, 4-Dipentoxyphenyl phosphine oxide or bis (2,4,6-trimethylbenzoyl) phenyl-phosphine oxide, (4-morpholinobenzoyl) -1-benzyl-1-dimethylaminopropane, 4- (methylthiobenzoyl) -1 -Methyl 1-morpholino ethane etc. is mentioned, but it is not limited to this.

  Among the active energy curing adhesives used in the present invention, any of the photoradical generators contained in the electron beam curing type, that is, hydrogen abstraction type or cleavage type photoradical generators can be used alone respectively. A plurality of other combinations may be used, but a combination of one or more cleavage-type photoradical generators is more preferable in terms of the stability of the single radical photogenerator and the curability. Among the cleavage type photoradical generators, acyl phosphine oxides are preferable, and more specifically, trimethyl benzoyl diphenyl phosphine oxide (trade name “DAROCURE TPO”; Ciba Japan Ltd.), bis (2,6-dimethoxy-) Benzoyl)-(2,4,4-trimethyl-pentyl) -phosphine oxide (trade name “CGI 403”; Ciba Japan Ltd.), or bis (2,4,6-trimethyl benzoyl) -2,4- Dipentoxyphenyl phosphine oxide (trade name “Irgacure 819”; Ciba Japan Ltd.) is preferable.

  The active energy ray-curable adhesive can contain a sensitizer as required. By using a sensitizer, the reactivity can be improved, and the mechanical strength and the adhesive strength of the adhesive layer can be further improved. As the sensitizer, those described above can be appropriately applied.

  When mix | blending a sensitizer, it is preferable to make the compounding quantity into the range of 0.1-20 mass parts with respect to 100 mass parts of total amounts of an active energy ray hardening-type adhesive agent.

  Various additives can be blended into the active energy ray-curable adhesive as long as the effect is not impaired. As an additive which can be blended, an ion trap agent, an antioxidant, a chain transfer agent, a tackifier, a thermoplastic resin, a filler, a flow control agent, a plasticizer, an antifoamer etc. are mentioned, for example.

  Each of these components which comprise an active energy ray hardening-type adhesive agent is usually used in the state melt | dissolved in the solvent. When the active energy ray-curable adhesive contains a solvent, the active energy ray-curable adhesive is applied to the coated surface and dried to obtain an adhesive layer. The components that do not dissolve in the solvent may be in the state of being dispersed in the system.

The active energy ray-curable adhesive is applied to the bonding surface of the first retardation layer 1 with the second retardation layer 2, the bonding surface of the second retardation layer 2 with the first retardation layer 1, or both of them. Be done. The adhesion surface of the first retardation layer 1 with the second retardation layer 2 and the adhesion surface of the second retardation layer 2 with the first retardation layer 1 are previously subjected to corona treatment, plasma treatment, flame treatment, etc. It is also possible to form a primer layer or the like.
The thickness of the primer layer is usually about 0.001 to 5 μm, preferably 0.01 μm or more, preferably 4 μm or less, and more preferably 3 μm or less. If the primer layer is too thick, the appearance of the composite retardation plate 5 tends to be poor.

  The viscosity of the active energy ray-curable adhesive may be any viscosity as long as it can be applied by various methods, but the viscosity at a temperature of 25 ° C. is preferably in the range of 10 to 1,000 mPa · sec. And more preferably in the range of 20 to 500 mPa · sec. If the viscosity is too small, layer formation with a desired thickness tends to be difficult. On the other hand, when the viscosity is too large, it tends to be difficult to flow and it becomes difficult to obtain a uniform coating film without unevenness. The viscosity referred to herein is a value measured at 10 rpm after temperature control of the adhesive at 25 ° C. using an E-type viscometer.

  The active energy ray-curable adhesive can be used in an electron beam-curable or ultraviolet-curable mode. In the present specification, an active energy ray is defined as an energy ray capable of decomposing a compound generating an active species to generate an active species. Examples of such active energy rays include visible light, ultraviolet light, infrared light, X-rays, α-rays, β-rays, γ-rays and electron beams.

  In the electron beam curing type, as the irradiation condition of the electron beam, any appropriate condition can be adopted as long as the above-mentioned active energy ray curing type adhesive can be cured. For example, in the electron beam irradiation, the acceleration voltage is preferably 5 kV to 300 kV, and more preferably 10 kV to 250 kV. If the acceleration voltage is less than 5 kV, the electron beam may not reach the adhesive and curing may be insufficient. If the acceleration voltage exceeds 300 kV, the penetration through the sample is too strong and the electron beam bounces, resulting in a transparent protective film or There is a risk of damaging the polarizer. The irradiation dose is 5 to 100 kGy, more preferably 10 to 75 kGy. If the irradiation dose is less than 5 kGy, the adhesive will be undercured, and if it exceeds 100 kGy, the retardation plate will be damaged, resulting in a decrease in mechanical strength and yellowing, and the desired optical properties can not be obtained.

  Electron beam irradiation is usually performed in an inert gas, but if necessary, it may be performed in the air or under a condition where a small amount of oxygen is introduced. By appropriately introducing oxygen, it is possible to cause oxygen inhibition to occur on the surface of the retardation plate that the electron beam first strikes, to prevent damage to the retardation plate, and efficiently irradiate the electron beam only to the adhesive. be able to.

In the ultraviolet curing type, the light irradiation intensity of the active energy ray curable adhesive is determined depending on the composition of the adhesive and is not particularly limited, but is preferably 10 to 1,000 mW / cm ² . If the light irradiation intensity to the resin composition is less than 10 mW / cm ² , the reaction time becomes too long, and if it exceeds 1,000 mW / cm ² , heat emitted from the light source and heat generation during polymerization of the composition occur. This may cause yellowing of the adhesive component material. The irradiation intensity is preferably an intensity in a wavelength range effective for activating the cationic photopolymerization initiator, more preferably an intensity in a wavelength range of 400 nm or less, and still more preferably a wavelength range of 280 to 320 nm Strength at Such once with light intensity or by irradiation a plurality of times, the integrated light quantity 10 mJ / cm ² or more, preferably be set to be 100~1,000mJ / cm ^2. When the accumulated light amount to the adhesive is less than 10 mJ / cm ² , generation of the active species derived from the polymerization initiator is not sufficient, and curing of the adhesive becomes insufficient. On the other hand, when the integrated light amount exceeds 1,000 mJ / cm ² , the irradiation time becomes very long, which is disadvantageous to the improvement of productivity. At this time, which wavelength region (UVA (320 to 390 nm), UVB (280 to 320 nm), etc.) requires the integrated light amount differs depending on the type of film of the retardation plate used and the combination of adhesive types.

  The light source used to carry out polymerization curing of the adhesive by irradiation of active energy rays in the present invention is not particularly limited, and, for example, low pressure mercury lamp, medium pressure mercury lamp, high pressure mercury lamp, super high pressure mercury lamp, xenon lamp, halogen lamp, carbon An arc lamp, a tungsten lamp, a gallium lamp, an excimer laser, an LED light source emitting a wavelength range of 380 to 440 nm, a chemical lamp, a black light lamp, a microwave excitation mercury lamp, and a metal halide lamp can be mentioned. From the viewpoint of energy stability and simplicity of the apparatus, an ultraviolet light source having a light emission distribution at a wavelength of 400 nm or less is preferable.

[Optical laminate]
The optical laminate of the present invention is a laminate of a polarizing plate and the above-mentioned composite retardation plate. The optical laminate may include a second adhesive layer for adhering the polarizing plate and the composite retardation plate. By adjusting the layer configuration of the composite retardation plate to be laminated on the polarizing plate, an optical laminate having antireflection performance can be obtained. The optical laminate having the antireflection performance is, for example, a circularly polarizing plate. In the image display device, a decrease in visibility due to the reflection of extraneous light can be suppressed by providing the optical laminate having the anti-reflection performance on the viewing side of the image display panel.

As a layer configuration of an optical laminate comprising the polarizing plate and the composite retardation plate, which can suppress a decrease in visibility due to reflection of extraneous light,
v) Optical of a layer configuration in which a polarizing plate, a 1⁄2 wavelength layer (first retardation layer), a second adhesive layer, and a 1⁄4 wavelength layer (second retardation layer) are laminated in this order from the viewing side Stack,
vi) Optical compensation layer layers (second retardation layer) such as a polarizing plate, a quarter wavelength layer (first retardation layer), a second adhesive layer, and a positive C plate are laminated in this order from the viewing side Optical laminate of the following layer configuration,
Is specifically illustrated.

  The thickness of the optical laminate is usually 50 to 500 μm, preferably 50 to 200 μm, and more preferably 50 to 150 μm from the viewpoint of thinning.

<Polarizer>
The polarizing plate may be a film having a polarizing function to obtain linearly polarized light from transmitted light. As the said film, the stretched film which made the pigment | dye which has absorption anisotropy adsorb | suck, or the film etc. which include the film which apply | coated the pigment | dye which has absorption anisotropy as a polarizer are mentioned. Examples of dyes having absorption anisotropy include dichroic dyes. A film coated with a dye having absorption anisotropy, which is used as a polarizer, is a stretched film on which a dye having absorption anisotropy is adsorbed, or a composition containing a dichroic dye having liquid crystallinity or The film etc. which have a liquid phase layer obtained by apply | coating the composition containing a color pigment and a polymeric liquid crystal are mentioned.

(Polarizer equipped with a stretched film as a polarizer)
The polarizing plate provided with the stretched film which made the pigment | dye which has absorption anisotropy adsorb | sucked as a polarizer is demonstrated. A stretched film having a dye having absorption anisotropy adsorbed thereon, which is a polarizer, is generally obtained by a process of uniaxially stretching a polyvinyl alcohol resin film, and staining the polyvinyl alcohol resin film with a dichroic dye. It is manufactured through a process of adsorbing a dichroic dye and a process of treating a polyvinyl alcohol-based resin film to which the dichroic dye is adsorbed with an aqueous solution of boric acid, and a process of washing with an aqueous solution of boric acid and washing with water. Such a polarizer may be used as it is as a polarizing plate, or one obtained by bonding a transparent protective film to at least one surface of such a polarizer may be used as a polarizing plate.

  The polyvinyl alcohol-based resin is obtained by saponifying a polyvinyl acetate-based resin. As the polyvinyl acetate resin, besides polyvinyl acetate which is a homopolymer of vinyl acetate, a copolymer of vinyl acetate and another monomer copolymerizable therewith is used. Examples of other monomers copolymerizable with vinyl acetate include unsaturated carboxylic acids, olefins, vinyl ethers, unsaturated sulfonic acids, and acrylamides having an ammonium group.

  The degree of saponification of the polyvinyl alcohol resin is usually about 85 to 100 mol%, preferably 98 mol% or more. The polyvinyl alcohol-based resin may be modified, and for example, polyvinyl formal modified with aldehydes and polyvinyl acetal can also be used. The polymerization degree of the polyvinyl alcohol-based resin is usually about 1,000 to 10,000, and preferably in the range of 1,500 to 5,000.

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

  Uniaxial stretching of the polyvinyl alcohol-based resin film can be performed before, simultaneously with, or after the dyeing with the dichroic dye. When uniaxial stretching is performed after dyeing, this uniaxial stretching may be performed before or during the boric acid treatment. Moreover, it is also possible to uniaxially stretch in these several steps. In uniaxial stretching, uniaxial stretching may be performed between rolls having different peripheral speeds, or uniaxial stretching may be performed using a heat roll. In addition, uniaxial stretching may be dry stretching in which stretching is performed in the air, or may be wet stretching in which a polyvinyl alcohol resin film is swollen using a solvent. The stretching ratio is usually about 3 to 8 times.

  Dyeing of a polyvinyl alcohol-based resin film with a dichroic dye is performed, for example, by a method of immersing a polyvinyl alcohol-based resin film in an aqueous solution containing a dichroic dye. Specifically, iodine or a dichroic organic dye is used as the dichroic dye. Dichroism organic dyes include dichroism direct dyes consisting of disazo compounds such as C. I. DIRECT RED 39, and dichroism direct dyes consisting of compounds such as trisazo and tetrakisazo. The polyvinyl alcohol-based resin film is preferably subjected to immersion treatment in water before the dyeing treatment.

  When using iodine as a dichroic dye, the method of immersing and dye | staining a polyvinyl-alcohol-type resin film the aqueous solution containing an iodine and potassium iodide is employ | adopted normally. The content of iodine in this aqueous solution is usually about 0.01 to 1 part by mass per 100 parts by mass of water. The content of potassium iodide is usually about 0.5 to 20 parts by mass per 100 parts by mass of water. The temperature of the aqueous solution used for dyeing is usually about 20 to 40 ° C. Moreover, the immersion time (staining time) to this aqueous solution is usually about 20 to 1,800 seconds.

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

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

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

  After washing with water, drying treatment is performed to obtain a polarizer. The drying process can be performed, for example, using a hot air dryer or a far infrared heater. The temperature of the drying treatment is usually about 30 to 100 ° C, preferably 50 to 80 ° C. The drying time is usually about 60 to 600 seconds, preferably 120 to 600 seconds. By the drying process, the moisture content of the polarizer is reduced to a practical level. The water content is usually about 5 to 20% by mass, preferably 8 to 15% by mass. When the moisture content is less than 5% by mass, the flexibility of the polarizer is lost, and the polarizer may be damaged or broken after it is dried. When the water content exceeds 20% by mass, the thermal stability of the polarizer may be deteriorated.

  Thus, the thickness of a polarizer obtained by uniaxially stretching, dyeing with a dichroic dye, boric acid treatment, washing with water and drying on a polyvinyl alcohol-based resin film is preferably 5 to 40 μm.

  The material of the protective film to be bonded to one side or both sides of the polarizer is not particularly limited, and, for example, a cellulose acetate system made of a resin such as a cyclic polyolefin resin film, triacetyl cellulose and diacetyl cellulose A film known in the art such as a resin film, a polyester resin film made of a resin such as polyethylene terephthalate, polyethylene naphthalate or polybutylene terephthalate, a polycarbonate resin film, a (meth) acrylic resin film, or a polypropylene resin film It can be mentioned. The thickness of the protective film is usually 300 μm or less, preferably 200 μm or less, more preferably 100 μm or less, and usually 5 μm or more, preferably 20 μm or more from the viewpoint of thinning. . In addition, the protective film on the viewing side may or may not have retardation. On the other hand, the protective film on the side to be laminated on the first retardation layer preferably has a retardation of 10 nm or less.

(Polarizer comprising a film having a liquid crystal layer as a polarizer)
A polarizing plate provided with a film having a liquid crystal layer as a polarizer will be described. As a film coated with a dye having absorption anisotropy, which is used as a polarizer, a composition containing a dichroic dye having liquid crystallinity or a composition containing a dichroic dye and a liquid crystal compound is applied. The obtained film etc. are mentioned. The said film may be used independently as a polarizing plate, and may be used as a polarizing plate by the structure which has a protective film in the single side | surface or both surfaces. As the said protective film, the same thing as a polarizing plate provided with the above-mentioned stretched film as a polarizer is mentioned.

  It is preferable that the film coated with the dye having absorption anisotropy is thin, but if it is too thin, the strength tends to be reduced and the processability tends to be poor. The thickness of the film is usually 20 μm or less, preferably 5 μm or less, and more preferably 0.5 μm or more and 3 μm or less.

  As a film which apply | coated the pigment | dye which has the said absorption anisotropy, the film as described in Unexamined-Japanese-Patent No. 2012-33249 etc. is mentioned specifically ,.

  By directly applying the dye having the absorption anisotropy to the first retardation layer side of the composite retardation plate, an optical laminate formed by laminating the composite retardation plate and a polarizing plate may be obtained. . In this case, the composite retardation plate and the polarizing plate can be laminated without having the second adhesive layer.

<Second adhesive layer>
The second adhesive layer can be composed of, for example, a pressure-sensitive adhesive, a water-based adhesive, an active energy ray-curable adhesive, and a combination thereof. Among these, since the second adhesive layer is a cured product layer of an active energy ray-curable adhesive, even when the optical laminate including the composite retardation layer of the present invention is bent, wrinkles in the bent portion It is preferable because it can further suppress the occurrence of As used herein, the term "second adhesive layer" includes not only an adhesive layer composed of an adhesive but also an adhesive layer composed of an adhesive.

  The description of the first adhesive layer applies to the adhesive forming the second adhesive layer, the water-based adhesive, and the active energy ray-curable adhesive. The first adhesive layer and the second adhesive layer may be formed of the same material or may be formed of different materials.

[Method of manufacturing composite retardation plate and optical laminate]
The composite retardation plate of the present invention comprises a first retardation layer 10 including a first retardation layer 13, a first alignment layer 12 and a first base layer 11 as shown in FIG. By laminating the second retardation layer 20 including the second retardation layer 23, the second alignment layer 22, and the first base layer 21 as shown in (B), through the first adhesive layer 40. It can be manufactured. Moreover, the composite retardation plate of the present invention includes the first retardation layer 13, the first alignment layer 12, the first base layer 11, the first adhesive layer 40, the second base layer 21, and the second alignment layer. The laminated body by which the 22 and the 2nd phase difference expression layer 23 were laminated | stacked in order may be used.

  As a method of bonding the first retardation layer 10 and the second retardation layer 20, either the bonding surface of the first retardation layer 10 or the bonding surface of the second retardation layer 20 or both of them may be coated. There is a method of processing, laminating the other bonding surface thereon, and curing the adhesive constituting the first adhesive layer.

  Various coating methods, such as a doctor blade, a wire bar, a die coater, a comma coater, a gravure coater, etc., can be utilized for coating of the adhesive agent which comprises a 1st adhesive bond layer, for example.

  As a method of curing the adhesive constituting the first adhesive layer, a method of curing may be appropriately selected depending on the type of the adhesive. When the adhesive is an active energy ray-curable adhesive, a method of curing with active energy rays as described above is preferable. Either or both of the bonding surface of the first retardation layer 10 or the bonding surface of the second retardation layer 20 may be subjected to corona treatment, plasma treatment, etc., or a primer layer may be formed. .

  The composite retardation layer of the present invention may be a laminate as shown in FIG. 3C, or a laminate in which at least one of the first base layer 11 and the second base layer 21 is peeled off. It may be In addition, it may be a laminate in which the first base material layer 11 and the first alignment layer 12 are separated from the laminate shown in FIG. 3 (C), or the laminate from the laminate shown in FIG. 3 (C). It may be a laminate in which the material layer 21 and the second alignment layer 22 are peeled off.

[Applications of Optical Laminate]
The optical laminated body which is a circularly-polarizing plate can be used for various image display apparatuses as an optical laminated body arrange | positioned at the visual recognition side of an image display panel, and providing an antireflection performance. The image display device is a device having an image display panel, and includes a light emitting element or a light emitting device as a light emission source. As an image display device, a liquid crystal display device, an organic electroluminescence (EL) display device, an inorganic electroluminescence (EL) display device, a touch panel display device, an electron emission display device (for example, field emission display (FED), surface field emission display Device (SED), electronic paper (display device using electronic ink or electrophoretic element, plasma display device, projection type display device (eg grating light valve (GLV) display device, display having digital micro mirror device (DMD)) Device) and a piezoelectric ceramic display etc. The liquid crystal display device may be any of a transmission type liquid crystal display device, a semi-transmission type liquid crystal display device, a reflection type liquid crystal display device, a direct view type liquid crystal display device and a projection type liquid crystal display device. These image display devices display two-dimensional images. The optical laminate, which is a circularly polarizing plate, may be provided with an image display panel having a bending portion. It can be effectively used for a luminescence (EL) display device.

  According to the present invention, it is possible to obtain an optical laminate free from the occurrence of wrinkles even when the optical laminate is bent and disposed along the surface of the image display panel having the bent portion.

Hereinafter, the present invention will be described in more detail by way of examples.
[Production example of retardation layer]
(1) Preparation of composition for liquid crystal retardation formation 80 parts of a polymerizable liquid crystal compound (A1), 20 parts of a polymerizable compound (A2), 6 parts of a polymerization initiator, 0.1 parts of a leveling agent and 400 parts of cyclopentanone The mixture was mixed, and the obtained mixture was stirred at 80 ° C. for 1 hour to obtain a composition (1) for forming a liquid crystal retardation.

The polymerizable compound A1, the polymerizable compound A2, the polymerization initiator and the leveling agent used are shown below. In addition, polymeric liquid crystal compound A1 and polymeric liquid crystal compound A2 were synthesize | combined by the method of Unexamined-Japanese-Patent No. 2010-31223.
Polymerizable Compound A1:

Polymerizable compound A2:

Polymerization initiator: 2-dimethylamino-2-benzyl-1- (4-morpholinophenyl) butan-1-one (IRGACURE 369; manufactured by Ciba Specialty Chemicals)
Leveling agent (0.1 part): polyacrylate compound (BYK-361N; manufactured by BYK-Chemie).

(2) Preparation of composition for forming alignment layer (2-1) Preparation of composition (1) for forming alignment layer 5 parts of the compound shown below and 95 parts of cyclopentanone are mixed, and the obtained mixture is heated to 80 ° C. The resultant was stirred for 1 hour to obtain a composition (1) for forming an alignment layer.
Photo-alignable material (5 parts):

(2-2) Preparation of Alignment Layer Forming Composition (2) An alignment layer forming composition (2) is obtained by adding 2-butoxyethanol to Sun Ever SE-610 (made by Nissan Chemical Industries, Ltd.) which is an alignment polymer. The The solid content in the alignment layer-forming composition (2) was 1%.

(3) Production Example of Retardation Layer (3-1) Production Example of Retardation Layer (1) (Production Example of Inverse Dispersive Quarter Wavelength Layer)
The surface of a film of polyethylene terephthalate (PET) was treated once using a corona treatment apparatus (AGF-B10, manufactured by Kasuga Denki Co., Ltd.) at an output of 0.3 kW and a treatment speed of 3 m / min. Composition for alignment layer formation (1) is bar-coated on the surface subjected to corona treatment, dried at 80 ° C. for 1 minute, and polarized UV irradiation device (SPOT CURE SP-7; manufactured by Ushio Electric Co., Ltd.) Then, polarized UV exposure was performed with an integrated light amount of 100 mJ / cm ² .
It was 100 nm when the film thickness of the obtained orientation layer was measured with a laser microscope (LEXT, manufactured by Olympus Corporation). Subsequently, the composition for forming a liquid crystal retardation (1) is coated on the alignment layer using a bar coater and dried at 120 ° C. for 1 minute, and then a high pressure mercury lamp (Unicure VB-15201BY-A, Ushio Inc. A retardation layer (reverse dispersion 1) including a liquid crystal layer as a retardation expression layer by irradiating ultraviolet light (in nitrogen atmosphere, wavelength: 365 nm, integrated light quantity at wavelength 365 nm: 1000 mJ / cm ² ) using a company-made product / 4 wavelength layer) was obtained. When the retardation value of the obtained retardation layer was measured, Re (550) = 138 nm and Rth (550) = 72 nm. Moreover, when the phase difference value of wavelength 450nm and wavelength 650nm was measured, it was Re (450) = 121 nm, Re (650) = 141 nm. The relationship of the in-plane retardation value at each wavelength is as follows. In addition, the retardation value of the film of a polyethylene terephthalate is not included.
Re (450) / Re (550) = 0.87
Re (650) / Re (550) = 1.02
(3-2) Production Example of Retardation Layer (2) (Production Example of Positive C Layer)
The surface of the film of cycloolefin polymer (COP) was treated once using a corona treatment apparatus at a power of 0.3 kW and a treatment speed of 3 m / min. The composition for alignment layer formation (2) was apply | coated to the surface which gave corona treatment using the bar coater, and it dried at 90 degreeC for 1 minute, and obtained the alignment film. It was 34 nm when the film thickness of the obtained orientation layer was measured with the laser microscope. Subsequently, the composition for forming a liquid crystal retardation (1) is applied on the alignment layer using a bar coater, dried at 90 ° C. for 1 minute, and then irradiated with ultraviolet light using a high pressure mercury lamp (under nitrogen atmosphere The integrated light quantity at a wavelength of 365 nm: 1000 mJ / cm ² ) was obtained to obtain a retardation layer (positive C layer) having a liquid crystal layer as a retardation expression layer. When the film thickness of the obtained retardation layer was measured by a laser microscope, the film thickness was 450 nm. Moreover, when the phase difference value in wavelength 550 nm of obtained retardation layer 2 was measured, it was Re (550) = 1 nm and Rth (550) = -70 nm. In addition, the retardation value of the film of a cycloolefin polymer is not included.

[Production Example of Photocurable Adhesives 1 to 11]
(1) Preparation of cationically curable component The cationically curable component shown below was prepared.

(A-1) 3 ', 4'-epoxycyclohexylmethyl 3,4-epoxycyclohexane carboxylate (trade name: CEL 2021 P, manufactured by Daicel Corporation),
(A-2) 1,2-epoxy-4- (2-oxiranyl) cyclohexane adduct of 2,2-bis (hydroxymethyl) -1-butanol (trade name: EHPE 3150, manufactured by Daicel Corporation),
(B-1) Neopentyl glycol diglycidyl ether (trade name: EX-211, Nagase ChemteX Co., Ltd.),
(B-2) 1,4-butanediol diglycidyl ether (trade name: EX-214, manufactured by Nagase ChemteX Co., Ltd.),
(B-3) 2-ethylhexyl glycidyl ether (trade name: EX-121, manufactured by Nagase ChemteX Co., Ltd.)
(C-1) Resorcinol diglycidyl ether (trade name: EX-201, Nagase ChemteX Co., Ltd.)
(C-2) Polyfunctional glycidyl ether (trade name: VG3101L, manufactured by PRINTEC CO., LTD.)
(D-1) 3-ethyl-3 {[(3-ethyloxetan-3-yl) methoxy] methyl} oxetane (trade name: OXT-221, Toagosei Co., Ltd.)
(D-2) xylylene bis oxetane (trade name: OXT-121, Toagosei Co., Ltd.)
(2) Preparation of Radical Curable Component A radical curable component shown below was prepared.

(E-1) 4-hydroxybutyl acrylate (trade name: 4HBA, manufactured by Nippon Kasei Co., Ltd.)
(E-2) 1,4-cyclohexanedimethanol monoacrylate (trade name: CHDMMA, manufactured by Nippon Kasei Co., Ltd.)
(E-3) Dimethylacrylamide (trade name: DMAA, manufactured by Kojin Co., Ltd.)
(E-4) Polyurethane Acrylate (trade name: Purple light UV-3000B, manufactured by Japan Synthetic Chemical Industry Co., Ltd.)
(3) Cationic Polymerization Initiator and Radical Polymerization Initiator A cationic polymerization initiator and a radical polymerization initiator (abbreviated as “initiator” in Table 1) shown below were prepared.

(F-1) Cationic polymerization initiator (trade name: CPI-100, manufactured by San-Apro Co., Ltd.)
(F-2) Radical polymerization initiator (trade name: IRGACURE 1173, manufactured by BASF)
(4) Preparation of Sensitizer A sensitizer shown below was prepared.
(G-1) 1,4-diethoxynaphthalene (abbreviated as "DEN" in Table 1)
(5) Preparation of Adhesives 1 to 11 After the above-mentioned cationic curable component and cationic polymerization initiator, or radical curable component and radical polymerization initiator are mixed in the blending ratio (unit is part) shown in Table 1 And defoamed to prepare photocurable adhesives 1-11. In addition, the cationic polymerization initiator (F-1) was mix | blended as a 50% propylene carbonate solution, Table 1 was displayed by the solid content.

[Preparation of adhesive 1]
(1) Preparation of Material An acrylic base polymer (G-1), an isocyanate crosslinking agent (G-2) and a silane coupling agent (G-3) shown below were prepared.

(H-1) Copolymer of butyl acrylate, methyl acrylate, acrylic acid and hydroxyethyl acrylate (H-2) Ethyl acetate solution (75% solid concentration) of trimethylol propane adduct of tolylene diisocyanate ("Coronate L (Product name), manufactured by Tosoh Corporation
(H-3) 3-glycidoxypropyltrimethoxysilane, liquid ("KBM-403" (trade name), manufactured by Shin-Etsu Chemical Co., Ltd.)
(2) Preparation of Adhesive 1 100 parts by mass of the above acrylic base polymer (H-1), 0.2 parts by mass of an isocyanate crosslinking agent (H-2), and silane coupling agent (H-3) 0 A pressure sensitive adhesive 1 was prepared by mixing with 2 parts by mass, stirring thoroughly and diluting with ethyl acetate.

[Viscosity measurement]
The viscosity at a temperature of 25 ° C. and 10 rpm was measured for the adhesives 1 to 11 prepared above using an E-type viscometer “TVE-25” manufactured by Toki Sangyo Co., Ltd. The results are shown in Table 1.

[Production example of composite retardation plate]
(1) Production of First Composite Retardation Plate (Examples 1 to 12 and Comparative Example 1) A 1⁄2 wavelength layer (the first layer comprising a retardation layer as a liquid phase layer, an alignment layer and a base layer) (1) phase difference layer) and a quarter wavelength layer (second phase difference layer) consisting of a phase difference developing layer which is a liquid crystal layer, an alignment layer and a base layer are cut into small pieces of 100 × 100 mm, and 1) The retardation layer, the adhesives (adhesives 1 to 11) shown in Table 2 and the second retardation layer are laminated in this order, with the retardation layer of each retardation layer facing inside I did. Then, they are laminated to obtain a laminate, and then, using a UV irradiation apparatus equipped with an ultraviolet lamp “H bulb” manufactured by Fusion UV Systems, from both sides of the laminate, the light irradiation intensity is 400 mW / cm ^2, by curing the photocurable adhesive to form a cured layer integrated quantity of light at a wavelength of 280~320nm is irradiated with ultraviolet rays so that 400 mJ / cm ^2, to obtain a laminate. The obtained laminate was used as a test piece of a composite retardation plate (Examples 1 to 12 and Comparative Example 1) after peeling off the first base layer and the second base layer.

(2) Production of First Composite Retardation Plate (Comparative Examples 2 and 3) In the same manner as in (1) above, 1 consisting of a retardation layer as a liquid phase layer, an orientation layer and a substrate layer 1 100 × 100 mm of 1⁄2 wavelength layer (first retardation layer) and 1⁄4 wavelength layer (second retardation layer) consisting of a retardation exhibiting layer which is a liquid crystal layer, an alignment layer and a base material layer The first retardation layer, the pressure-sensitive adhesive 1 and the second retardation layer were laminated in this order, with the retardation layer of each retardation layer inside. And these were bonded to a single sheet to obtain a laminate. The obtained laminate was used as a test piece of a composite retardation plate (comparative examples 2 and 3) after peeling off the first base layer and the second base layer.

(3) Production of Second Composite Retardation Plate (Examples 13 to 24 and Comparative Example 4) The inverse dispersive quarter-wave layer produced in the above-mentioned "(3-1) Production example of retardation layer (1)" (First retardation layer) and the positive C layer (second retardation layer) manufactured in the above “(3-2) production example of retardation layer (2)” are cut into small pieces of 100 × 100 mm; 1) The retardation layer, the adhesives (adhesives 1 to 11) shown in Table 3 and the second retardation layer are laminated in this order with the retardation layer of each retardation layer facing inside I did. Then, they are laminated to obtain a laminate, and then, using a UV irradiation apparatus equipped with an ultraviolet lamp “H bulb” manufactured by Fusion UV Systems, from both sides of the laminate, the light irradiation intensity is 400 mW / cm ^2, by curing the photocurable adhesive to form a cured layer integrated quantity of light at a wavelength of 280~320nm is irradiated with ultraviolet rays so that 400 mJ / cm ^2, to obtain a laminate. The obtained laminate was used as a test piece of a composite retardation plate (Examples 13 to 24 and Comparative Example 4) after peeling off the first base layer and the second base layer.

(4) Production of Second Composite Retardation Plate (Comparative Examples 5 and 6) In the same manner as the above (3), the reverse dispersion produced in the above-mentioned "(3-1) Production example of retardation layer (1)" 100 × 100 mm of a 1⁄4 wavelength layer (first retardation layer) and the positive C layer (second retardation layer) manufactured in the above “(3-2) Production example of retardation layer (2)” Small pieces were cut out, and the first retardation layer, the pressure-sensitive adhesive 1 and the second retardation layer were laminated in this order with the retardation expression layers of the respective retardation layers inside. And these were bonded to a single sheet to obtain a laminate. The obtained laminate was used as a test piece of a composite retardation plate (Comparative Examples 5 and 6) after the first base layer and the second base layer were peeled off.

(5) Thickness Measurement of Composite Retardation Plate and Adhesive Layer The thickness of the test piece of the composite retardation plate manufactured above was measured using a contact film thickness meter (trade name "DIGIMICRO MH-15M" manufactured by Nikon Corporation). It was measured. Further, the thickness of the cured adhesive layer or pressure-sensitive adhesive layer was measured in the same manner as the above method. The measurement results are shown in Tables 2 and 3.

(6) Measurement of piercing inclination in composite retardation plate The piercing inclination of the test piece of the composite retardation plate manufactured above was calculated. The piercing strength was measured using a small bench test machine [trade name "EZ Test" manufactured by Shimadzu Corp.] equipped with a piercing jig with a diameter of 1 mm and a radius of curvature of 0.5 R at the tip. The obtained piercing strength A (kg), piercing depth B (mm) before tearing, and composite retardation plate thickness d (mm), the following formula: E = A / (B × d)
The piercing inclination per unit film thickness E (kg / mm ² ) was calculated using The piercing inclination of the composite retardation plate is an average value of piercing inclinations E of five or more composite retardation plates manufactured under the same conditions. The measurement results are shown in Tables 2 and 3.

[Production Example of Optical Laminate]
(7) Production of Polarizing Plate A polyvinyl alcohol film having an average degree of polymerization of about 2,400 and a degree of saponification of at least 99.9 mol% and a thickness of 75 μm is immersed in pure water at 30 ° C., then iodine / potassium iodide / The dye was immersed in an aqueous solution having a mass ratio of water of 0.02 / 2/100 at 30 ° C. to perform iodine staining (iodine staining step). The polyvinyl alcohol film subjected to the iodine dyeing process was immersed in an aqueous solution having a mass ratio of potassium iodide / boric acid / water of 12/5/100 at 56.5 ° C. to perform boric acid treatment (boric acid treatment process) ). The polyvinyl alcohol film subjected to the boric acid treatment step was washed with pure water at 8 ° C. and then dried at 65 ° C. to obtain a polarizer (27 μm thickness after stretching) in which iodine is adsorbed and oriented to polyvinyl alcohol . At this time, stretching was performed in the iodine dyeing step and the boric acid treatment step. The total draw ratio in this drawing was 5.3. A saponified triacetyl cellulose film (trade name: KC4UYTAC, manufactured by Konica Minolta, 40 μm thick) was attached to both sides of the obtained polarizer with a nip roll via a water-based adhesive. It dried at 60 degreeC for 2 minutes, maintaining the tension | tensile_strength of the obtained bonded product to 430 N / m, and obtained the polarizing plate which has a triacetyl-cellulose film as a protective film on both surfaces. The above-mentioned water-based adhesive contains, in 100 parts of water, 3 parts of carboxyl group-modified polyvinyl alcohol (Klare Poval KL 318, manufactured by Kuraray) and a water-soluble polyamide epoxy resin (Sumirez resin 650, manufactured by Sumika Chemtex, 30% solid content concentration Prepared by adding 1.5 parts of an aqueous solution of

(8) Production of First Optical Laminate (Examples 1 to 12 and Comparative Examples 1 to 3) The polarizing plate produced in the above (7) and the first composite retardation plate produced in the above (1) or (2) The first optical laminate was manufactured by laminating an acrylic pressure-sensitive adhesive (film thickness 25 μm) such that the first retardation layer side of the first composite retardation plate was an adhesion surface. Specifically, with respect to the absorption axis direction (0 °) of the polarizing plate manufactured above, the first retardation layer is laminated in such a manner that the slow axis of the first retardation layer is −15 ° with counterclockwise rotation, and It laminated | stacked so that the transmission axis of the polarizing plate manufactured above and the slow axis of a 2nd phase difference layer might be -75 degrees.

(9) Production of Second Optical Laminate (Examples 13 to 24 and Comparative Examples 4 to 6) The polarizing plate produced in the above (8) and the second composite retardation plate produced in the above (3) or (4) To manufacture a second optical laminate. Specifically, the polarizing plate manufactured above is cut into pieces of 100 × 100 mm so that the slow axis of the first retardation layer is 45 ° with respect to the absorption axis direction (0 °) of the polarizer. An optical laminate, which is a circularly polarizing plate, laminated with an acrylic pressure-sensitive adhesive (film thickness 25 μm) so that this and the second composite retardation plate are such that the first retardation layer side is the adhesion surface Manufactured.

[Test example] (Evaluation of the occurrence of wrinkles)
The first optical laminate produced in the above (8) and the second optical laminate produced in the above (9) are used with an acrylic pressure-sensitive adhesive (film thickness 25 μm) so that the composite retardation plate side becomes an adhering surface. It bonded to the aluminum plate which has a bending part (2R), observed generation | occurrence | production of the wrinkles in a bending part visually, and evaluated generation | occurrence | production of the wrinkles based on the following references | standards. The evaluation results are shown in Tables 2 and 3.
1: No wrinkles were found at the inflection point,
2: It was confirmed that there were slight wrinkles in the bent portion (the number of wrinkles: 1 to 5),
3: It was confirmed that there were wrinkles in the bent portion (number of wrinkles: 5 or more).

  1 1st phase difference layer, 2 2nd phase difference layer, 4 1st adhesive layer, 5 composite phase difference plate, 10 1st phase difference layer, 11 1st base material layer, 12 1st orientation layer, 13 1st place Retardation layer, 20 second retardation layer, 21 second substrate layer, 22 second alignment layer, 23 second retardation layer, 40 first adhesive layer, 50 laminate (composite retardation plate), W width direction.

Claims (13)

A first retardation layer, a second retardation layer, and a first adhesive layer adhering the first retardation layer and the second retardation layer;
Piercing per unit thickness gradient is ^{6kg / mm 2 ~15kg / mm 2} , the composite retardation plate.   The composite retardation plate according to claim 1, wherein the first adhesive layer is a cured product layer of an active energy ray-curable adhesive.   The composite retardation plate according to claim 1 or 2, wherein the first retardation layer is a half wavelength layer, and the second retardation layer is a quarter wavelength layer.   The composite retardation plate according to claim 1 or 2, wherein the first retardation layer is a half wavelength layer or a quarter wavelength layer, and the second retardation layer is an optical compensation layer.   The composite retardation plate according to any one of claims 1 to 4, wherein at least one of the first retardation layer and the second retardation layer includes a retardation exhibiting layer which is a liquid crystal layer.   The composite retardation plate according to any one of claims 1 to 5, which has a thickness of 2 μm to 50 μm. A polarizing plate, and the composite retardation plate according to any one of claims 1 to 6 laminated on the polarizing plate,
The composite retardation plate is an optical laminate in which the first retardation layer is laminated in a direction toward the polarizing plate.   The optical laminated body of Claim 7 which is a circularly-polarizing plate.   The optical laminate according to claim 7, further comprising a second adhesive layer bonding the polarizing plate and the composite retardation plate.   The optical laminate according to claim 9, wherein the second adhesive layer is a cured product layer of an active energy ray-curable adhesive.   The image display apparatus containing an image display panel and the optical laminated body of any one of Claims 7-10 arrange | positioned at the visual recognition side of the said image display panel.   The image display device according to claim 11, wherein the optical laminate is disposed in a direction in which the polarizing plate is positioned on the viewing side.   The image display device according to claim 12, which is an organic electroluminescent display device.