JP2022110684A - optical laminate - Google Patents

Abstract

To provide an optical laminate which is suppressed in deterioration of durability of a polarizer and high in adhesion between the polarizer and other members in the optical laminate equipped with the polarizer having the surface on which a protective film is not provided.SOLUTION: Disclosed is an optical laminate having a polarizer containing a polyvinyl alcohol resin and a retardation body containing a cured product of a polymerizable liquid crystal compound, which includes: a first adhesive layer provided in contact with the polarizer between the polarizer and the retardation body; and a second adhesive layer provided in contact with the retardation body.SELECTED DRAWING: Figure 1

Description

The present invention relates to an optical layered body, and also relates to an image display device having the optical layered body.

2. Description of the Related Art Conventionally, in an image display device, a method has been adopted in which an optical layered body having antireflection performance is arranged on the viewing side of an image display panel to suppress deterioration in visibility due to reflection of extraneous light.

A circularly polarizing plate composed of a polarizer and a retardation film is known as an optical laminate having antireflection performance.

In the circularly polarizing plate, external light directed toward the image display panel is converted into linearly polarized light by the polarizer, and then converted into circularly polarized light by the following retardation layer. The external light converted to circularly polarized light is reflected on the surface of the image display panel, but the direction of rotation of the plane of polarization is reversed during this reflection, and after being converted to linearly polarized light by the phase difference medium, the following polarizer is shaded by As a result, emission to the outside is significantly suppressed.

When the image display device is used in a harsh environment, there is a problem that the optical properties of the polarizer tend to deteriorate. JP-A-2013-105036 describes that a polarizer having excellent durability can be obtained by increasing the boric acid content in the polarizer.

JP 2013-105036 A

In the optical laminate, the durability of the polarizer can be improved by attaching protective films to both sides of the polarizer. A configuration in which a protective film is provided only on one surface of the polarizer is advantageous from the viewpoint of thinning, but compared to a configuration in which protective films are laminated on both sides of the polarizer, durability is low. I had a problem. In addition, the present inventors have found that a configuration in which a protective film is provided only on one surface of a polarizer is a structure between another member such as a retardation film that is laminated on the surface of the polarizer that does not have a protective film. It was found that there was a problem of low adhesion.

The present invention provides an optical laminate comprising a polarizer having a surface on which a protective film is not provided, wherein deterioration in durability of the polarizer is suppressed and adhesion between the polarizer and other members is high. The purpose is to provide the body.

The present invention provides an optical layered body, an image display device, and a method for manufacturing an optical layered body, which are described below.
[1] An optical laminate having a polarizer containing a polyvinyl alcohol-based resin and a retardation film containing a cured product of a polymerizable liquid crystal compound,
An optical optical system comprising a first adhesive layer provided in contact with the polarizer and a second adhesive layer provided in contact with the retardation element, between the polarizer and the retardation element. laminate.
[2] the first adhesive layer has a tensile modulus of 2000 MPa or more at a temperature of 25° C.;
The optical laminate according to [1], wherein the second adhesive layer has a tensile modulus of 1900 MPa or less at a temperature of 25°C.
[3] The first adhesive layer is a cured product layer of a cationic polymerizable adhesive,
The optical laminate according to [1] or [2], wherein the second adhesive layer is a cured product layer of a radically polymerizable adhesive.
[4] The optical layered product according to any one of [1] to [3], wherein the retardation film includes a λ/4 layer.
[5] The optical laminate according to any one of [1] to [4], which is an antireflection polarizing plate.
[6] An image display device comprising an image display panel and the optical layered body according to [5] arranged in front of the image display panel.
[7] The image display device according to [5], wherein the image display panel is an organic EL display panel.
[8] A method for producing an optical laminate according to any one of [1] to [5],
applying a first adhesive to the surface of the polarizer and curing the first adhesive to form a first adhesive layer;
The first adhesive layer formed on the surface of the polarizer and the retardation film are laminated with a second adhesive interposed therebetween, and the second adhesive is cured to form a second adhesive layer. A method for manufacturing an optical layered body, comprising:

According to the present invention, there is provided an optical laminate including a polarizer having a surface not provided with a protective film, in which deterioration in durability of the polarizer is suppressed and adhesion between the polarizer and other members is improved. A high optical laminate can be provided.

BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic sectional drawing which shows typically an example of the optical laminated body of this invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings, but the present invention is not limited to the following embodiments. In all the drawings below, the scale of each component is adjusted appropriately to facilitate understanding, and the scale of each component shown in the drawings does not necessarily match the scale of the actual component.

<Optical laminate>
The optical laminate according to the present invention includes a polarizer containing a polyvinyl alcohol-based resin and a retardation body containing a cured product of a liquid crystal compound, and the polarizing light is provided between the polarizer and the retardation body. It has a first adhesive layer provided in contact with the element and a second adhesive layer provided in contact with the retardation element. In the optical layered body according to the present invention, the presence of the first adhesive layer and the second adhesive layer suppresses deterioration in the durability of the polarizer and improves the adhesion between the polarizer and other members. A high optical laminate can be provided.

One embodiment of the optical laminate according to the present invention will be described with reference to FIG. The optical laminate 100 shown in FIG. 1 has a linear polarizing plate 130, a first adhesive layer 150, a second adhesive layer 160, and a retardation film 140 in this order.

Linear polarizer 130 includes protective layer 131 and polarizer 132 in this order from the front side. The retardation film 140 includes a first retardation layer and a second retardation layer 142 in this order from the linear polarizing plate 130 side. The first retardation layer 141 and the second retardation layer 142 may be bonded by an interlayer bonding layer 143 .

The optical layered body may have, for example, a rectangular shape in plan view, preferably a rectangular shape having long sides and short sides, and more preferably a rectangular shape. Each layer constituting the optical layered body may have rounded corners, notched edges, or perforated edges.

The optical layered body can be used, for example, in image display devices and the like. The image display device is not particularly limited, and examples thereof include organic electroluminescence (organic EL) display devices, inorganic electroluminescence (inorganic EL) display devices, liquid crystal display devices, and electroluminescence display devices.

[Linear polarizing plate]
The linear polarizer 130 can be a polarizer 132 with a protective layer 131 laminated on one side thereof. The linear polarizing plate 130 has a property of transmitting linearly polarized light having a vibration plane orthogonal to the absorption axis when non-polarized light is incident thereon. The linear polarizing plate 130 contains a polyvinyl alcohol (hereinafter sometimes abbreviated as “PVA”) resin as a polarizer 132 .

The thickness of the linear polarizing plate 130 is, for example, 2 μm or more and 100 μm or less, preferably 5 μm or more and 60 μm or less.

[Polarizer]
A polarizer obtained by dyeing a polyvinyl alcohol-based resin film with iodine and uniaxially stretching can be used.

A polyvinyl alcohol-based resin can be produced by saponifying a polyvinyl acetate-based resin. The polyvinyl acetate-based resin may be polyvinyl acetate, which is a homopolymer of vinyl acetate, or may be a copolymer of vinyl acetate and another monomer that can be copolymerized with vinyl acetate. Other monomers copolymerizable with vinyl acetate include, for example, 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 or polyvinyl acetal modified with aldehydes may be used. The average degree of polymerization of the polyvinyl alcohol resin is usually about 1,000 to 10,000, preferably about 1,500 to 5,000. The average degree of polymerization of the polyvinyl alcohol-based resin can be determined according to JIS K 6726 (1994). If the average degree of polymerization is less than 1,000, it is difficult to obtain desirable polarizing performance, and if it exceeds 10,000, film workability may be poor.

As another method for producing a linear polarizing plate containing a polyvinyl alcohol resin film, first, a base film is prepared, a solution of a resin such as a polyvinyl alcohol resin is applied on the base film, and drying is performed to remove the solvent. to form a resin layer on the substrate film. A primer layer can be formed in advance on the surface of the substrate film on which the resin layer is formed. As the base film, a resin film such as PET, or a film using a resin that can be used for a protective layer, which will be described later, can be used. Examples of the material for the primer layer include a resin obtained by cross-linking a hydrophilic resin used for a linear polarizing plate.

Next, if necessary, the amount of solvent such as moisture in the resin layer is adjusted, then the base film and the resin layer are uniaxially stretched, and then the resin layer is dyed with a dichroic dye such as iodine to obtain two colors. The organic dye is adsorbed and oriented on the resin layer. Subsequently, if necessary, the resin layer on which the dichroic dye is adsorbed and oriented is treated with an aqueous boric acid solution, and a washing step is performed in which the aqueous boric acid solution is washed off. Thereby, a resin layer in which the dichroic dye is adsorbed and oriented, that is, a polarizer is manufactured. A known method can be adopted for each step.

The uniaxial stretching of the substrate film and the resin layer may be performed before dyeing, during dyeing, or during boric acid treatment after dyeing. Stretching may be performed. The base film and the resin layer may be uniaxially stretched in the MD direction (film transport direction). In this case, they may be uniaxially stretched between rolls with different peripheral speeds, or uniaxially stretched using hot rolls. You may Moreover, the base film and the resin layer may be uniaxially stretched in the TD direction (the direction perpendicular to the film transport direction), in which case a so-called tenter method can be used. The stretching of the substrate film and the resin layer may be dry stretching performed in the atmosphere, or wet stretching performed with the resin layer swollen with a solvent. In order to exhibit the performance of the polarizer layer, the draw ratio is 4 times or more, preferably 5 times or more, and particularly preferably 5.5 times or more. Although there is no particular upper limit for the draw ratio, it is preferably 8 times or less from the viewpoint of suppressing breakage and the like.

The polarizer produced by the above method may be used as a linear polarizing plate with the substrate film peeled off or together with the substrate film. According to the above method, the substrate film can be peeled off, so that the linear polarizing plate can be made thinner.

The thickness of the polarizer containing the polyvinyl alcohol resin film is, for example, 2 μm or more and 40 μm or less. The thickness of the polarizer may be 5 μm or more, 20 μm or less, 15 μm or less, or even 10 μm or less.

[Protective layer]
The protective layer 131 has a function of protecting the surface of the polarizer 132 . In the optical layered body, the linear polarizing plate 130 is arranged so that the protective layer 131 is on the front side of the polarizer 132 . The linear polarizing plate 130 may be configured without the protective layer 131 .

The protective layer 131 may be an organic layer or an inorganic layer. The protective layer 131 may be the base film used in the manufacturing process of the polarizer layer 132 . The organic layer can be formed using a composition for forming a protective layer, such as a (meth)acrylic resin composition, an epoxy resin composition, a polyimide resin composition, or the like. The protective layer-forming composition may be active energy ray-curable or thermosetting. The inorganic layer can be formed of silicon oxide or the like, for example. When the protective layer 131 is an organic layer, the protective layer may be called a hard coat layer.

When the protective layer 131 is an organic layer, the protective layer can be produced by, for example, applying an active energy ray-curable composition for forming a protective layer onto the base film and curing the composition by irradiating active energy. . The description of the above-mentioned base film is applied to the base film. The base film is usually removed by peeling. Examples of the method of applying the protective layer-forming composition include spin coating. When the protective layer 131 is an inorganic layer, the protective layer can be formed by, for example, a sputtering method, a vapor deposition method, or the like. When the protective layer 131 is an organic layer or an inorganic layer, the thickness of the protective layer 131 may be, for example, 0.1 μm or more and 10 μm or less, preferably 0.5 μm or more and 5 μm or less.

As the protective layer 131, for example, a resin film that is excellent in transparency, mechanical strength, thermal stability, water barrier properties, isotropy, stretchability, and the like can be used. The resin film may be a thermoplastic resin film. Specific examples of such resins include cellulose resins such as triacetyl cellulose; polyester resins such as polyethylene terephthalate and polyethylene naphthalate; polyethersulfone resins; polysulfone resins; polycarbonate resins; Polyimide resins; polyolefin resins such as polyethylene, polypropylene, and ethylene/propylene copolymers; cyclic polyolefin resins having cyclo- and norbornene structures (also referred to as norbornene-based resins); (meth)acrylic resins; polyarylate resins; polystyrene resins; Mention may be made of alcohol resins, as well as mixtures thereof. When protective layers are laminated on both sides of the polarizer layer, the two protective layers may be of the same type or of different types. The thickness of the resin film may be, for example, 3 μm or more and 50 μm or less, preferably 5 μm or more and 30 μm or less.

[First Adhesive Layer, Second Adhesive Layer]
The first adhesive layer 150 is provided in contact with the surface of the polarizer 132 opposite to the protective layer 131 side. The first adhesive layer 150 may be formed by curing the first adhesive. The first adhesive layer 150 preferably has a tensile modulus at 25° C. of 2000 MPa or more, more preferably 2100 MPa or more, and even more preferably 2200 MPa or more. The first adhesive layer 150 has a tensile elastic modulus of, for example, 4000 MPa or less at a temperature of 25°C. When the tensile elastic modulus of the first adhesive layer 150 is within the above range, it is possible to suppress the dichroic dye such as iodine adsorbed and oriented in the polarizer 132 from flowing out of the polarizer 132. The durability of the polarizer 132 can be improved, and the durability of the optical properties of the optical layered body can be improved.

The second adhesive layer 160 is provided in contact with the surface of the retardation film 140 on the side facing the linear polarizing plate 130 . The second adhesive layer 160 may be formed by curing the second adhesive. The second adhesive layer 160 preferably has a tensile modulus at 25° C. of 1900 MPa or less, more preferably 1800 MPa or less, and even more preferably 1700 MPa or less. The second adhesive layer 160 has a tensile elastic modulus of, for example, 100 MPa or more at a temperature of 25°C. When the tensile elastic modulus of the second adhesive layer 160 is within the above range, the adhesion between the polarizer 132 and the retardation film 140 can be improved in the optical laminate 100 . When the surface of the retardation film 140 on the side facing the polarizer 132 contains a cured product of a polymerizable liquid crystal compound, the problem of low adhesion between the polarizer 132 and the retardation film 140 is significant. According to the invention, even when the surface of the retardation film 140 facing the polarizer 132 contains a cured polymerizable liquid crystal compound, the adhesion can be improved.

The method for measuring the tensile elastic modulus of the first adhesive layer 150 and the second adhesive layer 160 is according to the method described in Examples below. The optical layered body 100 may be configured to further include another adhesive layer between the first adhesive layer 150 and the second adhesive layer 160 .

A curable adhesive containing a curable (polymerizable) compound is preferably used as the first adhesive forming the first adhesive layer 150 and the second adhesive forming the second adhesive layer 160 . The curable adhesive is preferably an active energy ray-curable adhesive that is cured by heating or irradiation with active energy rays such as ultraviolet rays, visible light, electron beams, and X-rays. Curable adhesives include radically polymerizable adhesives containing a radically polymerizable compound and cationically polymerizable adhesives containing a cationically polymerizable compound.

The first adhesive is preferably a cationically polymerizable adhesive from the viewpoint of facilitating the formation of the first adhesive layer 150 having the above-described tensile elastic modulus. may The second adhesive is preferably a radically polymerizable adhesive from the viewpoint of facilitating the formation of the second adhesive layer 160 having the tensile elastic modulus described above, and contains a cationically polymerizable compound together with a radically polymerizable compound. may The second adhesive is a radically polymerizable adhesive when the surface of the retarder 140 on which the second adhesive layer 160 is formed contains a cured product of a radically polymerizable compound. and the polarizer 132 can be further improved. The tensile modulus of elasticity of the first adhesive layer 150 and the second adhesive layer 160 can be adjusted by the type of adhesive, degree of curing of the adhesive, and the like. In the first adhesive layer 150, the curing degree of the first adhesive is preferably 98% or more, more preferably 99% or more. In the second adhesive layer 160, the hardening degree of the second adhesive is preferably 90% or more, more preferably 92% or more.

The thickness of the first adhesive layer 150 and the second adhesive layer 160 is preferably 20 μm or less, more preferably 15 μm or less, even more preferably 10 μm or less, even if it is 5 μm or less. Also, it is 0.05 μm or more, and may be 0.5 μm or more. When an active energy ray-curable adhesive is used, it may have a viscosity that allows it to be applied by various methods. It is preferably in the range, more preferably in the range of 20 to 500 mPa·sec. If the viscosity is too low, it tends to be difficult to form a layer with a desired thickness. On the other hand, if the viscosity is too high, it tends to become difficult to flow, making it difficult to obtain a uniform and uniform coating film. The viscosity here is a value measured at 10 rpm after adjusting the temperature of the adhesive to 25° C. using an E-type viscometer.

(cationically polymerizable adhesive)
The cationically polymerizable compound contained in the cationically polymerizable adhesive refers to a compound or oligomer that undergoes a cationic polymerization reaction and cures when irradiated with active energy rays such as ultraviolet rays, visible light, electron beams, and X-rays, or by heating. compounds, oxetane compounds, vinyl compounds, and the like. Among them, preferred cationic polymerizable compounds are epoxy compounds. An epoxy compound is a compound having one or more, preferably two or more epoxy groups in the molecule. Epoxy compounds may be used alone or in combination of two or more. Examples of epoxy compounds include alicyclic epoxy compounds, aromatic epoxy compounds, hydrogenated epoxy compounds, and aliphatic epoxy compounds. Among them, the epoxy compound preferably contains an alicyclic epoxy compound or an aliphatic epoxy compound, and more preferably contains an alicyclic epoxy compound, from the viewpoint of weather resistance, curing speed and adhesiveness.

An alicyclic epoxy compound is a compound having one or more epoxy groups bonded to an alicyclic ring in the molecule. The “epoxy group bonded to an alicyclic ring” means a bridging oxygen atom —O— in the structure represented by formula (I) below. In the following formula (I), m is an integer of 2-5.

A compound in which one or more hydrogen atoms in (CH ₂ ) _m in the above formula (I) are removed and the group is bonded to another chemical structure can be an alicyclic epoxy compound. One or more hydrogen atoms in (CH ₂ ) _m may optionally be substituted with a linear alkyl group such as methyl or ethyl.

Among them, an alicyclic epoxy compound having an epoxycyclopentane structure [m = 3 in the above formula (I)] or an epoxycyclohexane structure [m = 4 in the above formula (I)] is a cured glass. It has a high transition temperature and is also advantageous in terms of adhesion between the polarizing film and the protective film. Specific examples of alicyclic epoxy compounds are listed below. Here, the compound names are listed first, and then the corresponding chemical formulas are shown, and the compound names and the corresponding chemical formulas are given the same symbols.

A: 3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexanecarboxylate,
B: 3,4-epoxy-6-methylcyclohexylmethyl 3,4-epoxy-6-methylcyclohexanecarboxylate,
C: ethylene bis(3,4-epoxycyclohexanecarboxylate),
D: bis(3,4-epoxycyclohexylmethyl) adipate,
E: bis (3,4-epoxy-6-methylcyclohexylmethyl) adipate,
F: diethylene glycol bis(3,4-epoxycyclohexylmethyl ether),
G: ethylene glycol bis(3,4-epoxycyclohexylmethyl ether),
H: 2,3,14,15-diepoxy-7,11,18,21-tetraoxatrispiro[5.2.2.5.2.2]henicosane,
I: 3-(3,4-epoxycyclohexyl)-8,9-epoxy-1,5-dioxaspiro[5.5]undecane,
J: 4-vinylcyclohexene dioxide,
K: limonene oxide,
L: bis(2,3-epoxycyclopentyl) ether,
M: dicyclopentadiene dioxide.

An aromatic epoxy compound is a compound having an aromatic ring and an epoxy group in its molecule. Specific examples include bisphenol-type epoxy compounds such as diglycidyl ether of bisphenol A, diglycidyl ether of bisphenol F, and diglycidyl ether of bisphenol S, or oligomers thereof; phenol novolak epoxy resin, cresol novolak epoxy resin, hydroxybenzaldehyde phenol novolak. novolac epoxy resins such as epoxy resins; polyfunctional epoxies such as glycidyl ether of 2,2′,4,4′-tetrahydroxydiphenylmethane and glycidyl ether of 2,2′,4,4′-tetrahydroxybenzophenone Compounds; including polyfunctional epoxy resins such as epoxidized polyvinyl phenol.

The hydrogenated epoxy compound is a glycidyl ether of a polyol having an alicyclic ring, and is a nuclear hydrogenated polyol obtained by selectively hydrogenating the aromatic ring of an aromatic polyol under pressure in the presence of a catalyst. It can be a glycidyl-etherified hydroxy compound. Specific examples of aromatic polyols include bisphenol type compounds such as bisphenol A, bisphenol F and bisphenol S; novolac type resins such as phenol novolak resin, cresol novolak resin and hydroxybenzaldehyde phenol novolak resin; tetrahydroxydiphenylmethane, tetrahydroxy Including polyfunctional compounds such as benzophenone and polyvinylphenol. A glycidyl ether can be obtained by reacting epichlorohydrin with an alicyclic polyol obtained by subjecting an aromatic ring of an aromatic polyol to a hydrogenation reaction. Preferred among the hydrogenated epoxy compounds are hydrogenated diglycidyl ethers of bisphenol A.

Aliphatic epoxy compounds are compounds having at least one oxirane ring (three-membered cyclic ether) bonded to an aliphatic carbon atom in the molecule. For example, monofunctional epoxy compounds such as butyl glycidyl ether and 2-ethylhexyl glycidyl ether; Epoxy compounds; Trimethylolpropane triglycidyl ether, pentaerythritol tetraglycidyl ether and other trifunctional or higher epoxy compounds; , epoxy compounds having an oxirane ring bonded to an aliphatic carbon atom, and the like. Among them, from the viewpoint of adhesion between the polarizing film and the protective film, a bifunctional epoxy compound (also referred to as an aliphatic diepoxy compound) having two oxirane rings bonded to aliphatic carbon atoms in the molecule is preferred. Such suitable aliphatic diepoxy compounds can be represented, for example, by formula (II) below.

Y in the above formula (II) is an alkylene group having 2 to 9 carbon atoms, an alkylene group having a total carbon number of 4 to 9 interposed by an ether bond, or a bivalent carbon number of 6 to 18 having an alicyclic structure. is a hydrocarbon group of

The aliphatic diepoxy compound represented by the above formula (II) is specifically a diglycidyl ether of an alkanediol, a diglycidyl ether of an oligoalkylene glycol having a repeating number of up to about 4, or a diglycidyl ether of an alicyclic diol. is.

Specific examples of diols (glycols) capable of forming the aliphatic diepoxy compound represented by formula (II) are shown below. Alkanediols include ethylene glycol, propylene glycol, 1,3-propanediol, 2-methyl-1,3-propanediol, 2-butyl-2-ethyl-1,3-propanediol and 1,4-butanediol. , neopentyl glycol, 3-methyl-2,4-pentanediol, 2,4-pentanediol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 2-methyl-2,4-pentane Diol, 2,4-diethyl-1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 3,5-heptanediol, 1,8-octanediol, 2-methyl-1,8 -octanediol, 1,9-nonanediol, and the like. Oligoalkylene glycols include diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol and the like. Alicyclic diols include cyclohexanediol, cyclohexanedimethanol, and the like.

An oxetane compound, which is one of the cationic polymerizable compounds, is a compound containing one or more oxetane rings (oxetanyl group) in the molecule, and specific examples thereof include 3-ethyl-3-hydroxymethyloxetane (oxetane alcohol ), 2-ethylhexyloxetane, 1,4-bis[{(3-ethyloxetan-3-yl)methoxy}methyl]benzene (also called xylylenebisoxetane.), 3-ethyl-3[{( 3-ethyloxetan-3-yl)methoxy}methyl]oxetane, 3-ethyl-3-(phenoxymethyl)oxetane, 3-(cyclohexyloxy)methyl-3-ethyloxetane. The oxetane compound may be used as the main component of the cationically polymerizable compound, or may be used together with the epoxy compound. The combined use of an oxetane compound may improve the curing speed and adhesiveness.

Vinyl compounds that can be cationic polymerizable compounds include aliphatic or alicyclic vinyl ether compounds, specific examples of which include n-amyl vinyl ether, i-amyl vinyl ether, n-hexyl vinyl ether, and n-octyl vinyl ether. , 2-ethylhexyl vinyl ether, n-dodecyl vinyl ether, stearyl vinyl ether, vinyl ethers of alkyl or alkenyl alcohols having 5 to 20 carbon atoms, such as oleyl vinyl ether; 2-hydroxyethyl vinyl ether, 3-hydroxypropyl vinyl ether, 4-hydroxybutyl vinyl ether, etc. hydroxyl group-containing vinyl ether; vinyl ether of monoalcohol having an aliphatic or aromatic ring such as cyclohexyl vinyl ether, 2-methylcyclohexyl vinyl ether, cyclohexylmethyl vinyl ether, benzyl vinyl ether; glycerol monovinyl ether, 1,4-butanediol monovinyl ether, 1, 4-butanediol divinyl ether, 1,6-hexanediol divinyl ether, neopentyl glycol divinyl ether, pentaerythritol divinyl ether, pentaerythritol tetravinyl ether, trimethylolpropane divinyl ether, trimethylolpropane trivinyl ether, 1,4-dihydroxycyclohexane Mono-polyvinyl ethers of polyhydric alcohols such as monovinyl ether, 1,4-dihydroxycyclohexanedivinyl ether, 1,4-dihydroxymethylcyclohexane monovinyl ether, 1,4-dihydroxymethylcyclohexanedivinyl ether; diethylene glycol divinyl ether, triethylene glycol divinyl ether; Polyalkylene glycol mono-divinyl ethers such as vinyl ether, diethylene glycol monobutyl monovinyl ether; other vinyl ethers such as glycidyl vinyl ether, ethylene glycol vinyl ether methacrylate. A vinyl compound may be used as the main component of the cationically polymerizable compound, or may be used in combination with an epoxy compound, or an epoxy compound and an oxetane compound. By using a vinyl compound together, it may be possible to improve the curing speed and the viscosity reduction of the adhesive.

The cationic polymerizable adhesive can further contain other curable compounds than those mentioned above. Specific examples of other curable compounds are cationically polymerizable compounds other than those mentioned above, such as lactone compounds, cyclic acetal compounds, cyclic thioether compounds, and spiro-orthoester compounds.

When the first adhesive is a cationic polymerizable adhesive, from the viewpoint of suppressing the outflow of a dichroic dye such as iodine from the polarizer 132, the total amount of the curable compound contained in the first adhesive is 100. When expressed as % by mass, the cationically polymerizable compound (the content of all cationically polymerizable compounds contained in the first adhesive, and the total content thereof when two or more kinds of cationically polymerizable compounds are contained) The content of is preferably 80% by weight or more, more preferably 90% by weight or more, and even more preferably 100% by weight.

The first adhesive may be active energy ray-curable or thermosetting, but is preferably active energy ray-curable. When imparting active energy ray curability to the first adhesive, it is preferable to blend a photo cationic polymerization initiator into the adhesive. Photocationic polymerization initiators generate cationic species or Lewis acids by irradiation with active energy rays such as visible light, ultraviolet rays, X-rays, or electron beams, and initiate the polymerization reaction of cationic curable compounds. . Since the photocationic polymerization initiator acts catalytically with light, it is excellent in storage stability and workability even when mixed with a photocationically curable compound. Examples of compounds that generate cationic species or Lewis acids upon irradiation with active energy rays include onium salts such as aromatic iodonium salts and aromatic sulfonium salts, aromatic diazonium salts, and iron-arene complexes.

An aromatic iodonium salt is a compound having a diaryliodonium cation, typically a diphenyliodonium cation. Aromatic sulfonium salts are compounds having a triarylsulfonium cation, and typical cations include triphenylsulfonium cations and 4,4'-bis(diphenylsulfonio)diphenylsulfide cations. An aromatic diazonium salt is a compound having a diazonium cation, typically a benzenediazonium cation. Also, the iron-arene complex is typically a cyclopentadienyl iron(II) arene cation complex salt.

The cations shown above are paired with anions (anions) to form photocationic polymerization initiators. Examples of anions constituting the photocationic polymerization initiator include special phosphorus anions [(Rf) _n PF _6-n ] ⁻ , hexafluorophosphate anions PF ₆ ⁻ , hexafluoroantimonate anions SbF ₆ ⁻ , pentafluoro hydroxyantimonate anion SbF ₅ (OH) ⁻ , hexafluoroarsenate anion AsF ₆ ⁻ , tetrafluoroborate anion BF ₄ ⁻ , tetrakis(pentafluorophenyl)borate anion B(C ₆ F ₅ ) ₄ ^{− and} the like. Among them, the special phosphorus-based anions [(Rf) _n PF _6-n ] ⁻ and the hexafluorophosphate anion PF ₆ ⁻ are preferred from the viewpoint of the curability of the cationic polymerizable compound and the safety of the resulting adhesive layer. .

The photocationic polymerization initiator may be used alone or in combination of two or more. Among them, aromatic sulfonium salts are preferably used because they have ultraviolet absorption properties even in a wavelength region around 300 nm, so that they are excellent in curability and can give a cured product having good mechanical strength and adhesive strength.

The amount of the cationic photopolymerization initiator compounded is usually 0.5 to 10 parts by weight, preferably 6 parts by weight or less, per 100 parts by weight of the cationic polymerizable compound. By blending 0.5 parts by weight or more of the cationic photopolymerization initiator, the cationic polymerizable compound can be sufficiently cured, and high mechanical strength and adhesive strength can be imparted to the resulting optical laminate. On the other hand, if the amount is excessively large, the ionic substance in the cured product increases, resulting in an increase in the hygroscopicity of the cured product, which may reduce the durability of the polarizer. Examples of photocurable resins include (meth)acrylic resins, urethane resins, (meth)acrylic urethane resins, epoxy resins, and silicone resins. Examples of water-soluble polymers include poly(meth)acrylamide-based polymers; polyvinyl alcohol, ethylene-vinyl alcohol copolymers, ethylene-vinyl acetate copolymers, (meth)acrylic acid or its anhydride-vinyl alcohol copolymers. vinyl alcohol-based polymers such as coalescence; carboxyvinyl-based polymers; polyvinylpyrrolidone; starches; sodium alginate;

(radical polymerizable adhesive)
The radically polymerizable compound contained in the radically polymerizable adhesive refers to a compound or oligomer that undergoes a radical polymerization reaction and cures when irradiated with active energy rays such as ultraviolet rays, visible light, electron beams, and X-rays, or by heating. A typical example is a compound having an ethylenically unsaturated bond. Compounds having an ethylenically unsaturated bond include (meth)acrylic compounds having one or more (meth)acryloyl groups in the molecule, as well as styrene, styrenesulfonic acid, vinyl acetate, vinyl propionate, and N-vinyl. vinyl compounds such as -2-pyrrolidone; Among them, preferred radically polymerizable compounds are (meth)acrylic compounds.

The (meth)acrylic compound is obtained by reacting two or more kinds of a (meth)acrylate monomer having at least one (meth)acryloyloxy group in the molecule, a (meth)acrylamide monomer, and a functional group-containing compound. and (meth)acryloyl group-containing compounds such as (meth)acrylic oligomers having at least two (meth)acryloyl groups in the molecule. The (meth)acrylic oligomer is preferably a (meth)acrylate oligomer having at least two (meth)acryloyloxy groups in the molecule. The (meth)acrylic compounds may be used singly or in combination of two or more.

(Meth)acrylate monomers include monofunctional (meth)acrylate monomers having one (meth)acryloyloxy group in the molecule, and bifunctional (meth)acrylates having two (meth)acryloyloxy groups in the molecule. Examples include monomers and polyfunctional (meth)acrylate monomers having 3 or more (meth)acryloyloxy groups in the molecule.

Examples of monofunctional (meth)acrylate monomers are alkyl (meth)acrylates. In the alkyl (meth)acrylate, the alkyl group may be linear or branched as long as it has 3 or more carbon atoms. Specific examples of alkyl (meth)acrylates include methyl (meth)acrylate, ethyl (meth)acrylate, isopropyl (meth)acrylate, butyl (meth)acrylate, isobutyl (meth)acrylate, t-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate and the like. Also, aralkyl (meth)acrylates such as benzyl (meth)acrylate; terpene alcohol (meth)acrylates such as isobornyl (meth)acrylate; tetrahydrofurfuryl structures such as tetrahydrofurfuryl (meth)acrylate (meth) ) acrylate; cyclohexyl (meth)acrylate, cyclohexylmethyl methacrylate, dicyclopentanyl acrylate, dicyclopentenyl (meth)acrylate, 1,4-cyclohexanedimethanol monoacrylate having a cycloalkyl group at the alkyl group site (meth ) acrylates; aminoalkyl (meth)acrylates such as N,N-dimethylaminoethyl (meth)acrylate; 2-phenoxyethyl (meth)acrylate, dicyclopentenyloxyethyl (meth)acrylate, ethyl carbitol (meth)acrylate A (meth)acrylate having an ether bond at an alkyl moiety such as phenoxypolyethylene glycol (meth)acrylate can also be used as a monofunctional (meth)acrylate monomer.

Furthermore, monofunctional (meth)acrylates having a hydroxyl group in the alkyl moiety and monofunctional (meth)acrylates having a carboxyl group in the alkyl moiety can also be used. Specific examples of monofunctional (meth)acrylates having a hydroxyl group in the alkyl moiety include 2-hydroxyethyl (meth)acrylate, 2- or 3-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 2-hydroxy -3-phenoxypropyl (meth)acrylate, trimethylolpropane mono(meth)acrylate, pentaerythritol mono(meth)acrylate. Specific examples of monofunctional (meth)acrylates having a carboxyl group in the alkyl moiety include 2-carboxyethyl (meth)acrylate, ω-carboxy-polycaprolactone (n≈2) mono(meth)acrylate, 1-[2-( meth)acryloyloxyethyl]phthalic acid, 1-[2-(meth)acryloyloxyethyl]hexahydrophthalic acid, 1-[2-(meth)acryloyloxyethyl]succinic acid, 4-[2-(meth)acryloyl oxyethyl]trimellitic acid, N-(meth)acryloyloxy-N',N'-dicarboxymethyl-p-phenylenediamine.

The (meth)acrylamide monomer is preferably a (meth)acrylamide having a substituent at the N-position, and a typical example of the substituent at the N-position is an alkyl group, but the nitrogen atom of the (meth)acrylamide may form a ring together, and this ring may have an oxygen atom as a ring member in addition to the carbon atom and the nitrogen atom of (meth)acrylamide. Furthermore, substituents such as alkyl and oxo (=O) may be bonded to carbon atoms constituting the ring.

Specific examples of N-substituted (meth)acrylamides include N-methyl (meth)acrylamide, N-ethyl (meth)acrylamide, N-isopropyl (meth)acrylamide, Nn-butyl (meth)acrylamide, Nt- N-alkyl (meth)acrylamides such as butyl (meth)acrylamide and N-hexyl (meth)acrylamide; N,N-, such as N,N-dimethyl (meth)acrylamide and N,N-diethyl (meth)acrylamide Contains dialkyl (meth) acrylamide. The N-substituent may also be an alkyl group having a hydroxyl group, examples of which include N-hydroxymethyl(meth)acrylamide, N-(2-hydroxyethyl)(meth)acrylamide, N-(2-hydroxy propyl) (meth) acrylamide and the like. Further, specific examples of the N-substituted (meth)acrylamides forming the 5- or 6-membered ring mentioned above include N-acryloylpyrrolidine, 3-acryloyl-2-oxazolidinone, 4-acryloylmorpholine, N-acryloyl Piperidine, N-methacryloyl piperidine and the like.

Bifunctional (meth)acrylate monomers include alkylene glycol di(meth)acrylates, polyoxyalkylene glycol di(meth)acrylates, halogen-substituted alkylene glycol di(meth)acrylates, di(meth)acrylates of aliphatic polyols, hydrogenated Di(meth)acrylate of dicyclopentadiene or tricyclodecanedialkanol, di(meth)acrylate of dioxaneglycol or dioxanedialkanol, di(meth)acrylate of alkylene oxide adduct of bisphenol A or bisphenol F, bisphenol A or bisphenol Epoxy di(meth)acrylate of F and the like.

More specific examples of bifunctional (meth)acrylate monomers include ethylene glycol di(meth)acrylate, 1,3-butanediol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, 1 ,6-hexanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, trimethylolpropane di(meth)acrylate, pentaerythritol di(meth)acrylate, ditri methylolpropane di(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, dipropylene glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, polytetramethylene glycol di(meth)acrylate, silicone di(meth)acrylate, di(meth)acrylate of neopentylglycol hydroxypivalate, 2,2-bis[4-(meth) Acryloyloxyethoxyethoxyphenyl]propane, 2,2-bis[4-(meth)acryloyloxyethoxyethoxycyclohexyl]propane, hydrogenated dicyclopentadienyl di(meth)acrylate, tricyclodecanedimethanol di(meth)acrylate , 1,3-dioxane-2,5-diyl di(meth)acrylate [alias: dioxane glycol di(meth)acrylate], acetal compound of hydroxypivalaldehyde and trimethylolpropane [chemical name: 2-(2-hydroxy -1,1-dimethylethyl)-5-ethyl-5-hydroxymethyl-1,3-dioxane], tris(hydroxyethyl)isocyanurate di(meth)acrylate, and the like.

Tri- or higher polyfunctional (meth)acrylate monomers include glycerin tri(meth)acrylate, alkoxylated glycerin tri(meth)acrylate, trimethylolpropane tri(meth)acrylate, ditrimethylolpropane tri(meth)acrylate, ditrimethylol Propane tetra(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, etc. Poly (meth) acrylates of tri- or more functional aliphatic polyols are typical, and tri (meth) acrylates of tri- or more halogen-substituted polyols, tri (meth) alkylene oxide adducts of glycerin acrylates, tri(meth)acrylates of alkylene oxide adducts of trimethylolpropane, 1,1,1-tris[(meth)acryloyloxyethoxyethoxy]propane, tris(hydroxyethyl)isocyanurate tri(meth)acrylates, and the like; be done.

On the other hand, (meth)acrylic oligomers include urethane (meth)acrylic oligomers, polyester (meth)acrylic oligomers, epoxy (meth)acrylic oligomers, and the like.

A urethane (meth)acrylic oligomer is a compound having a urethane bond (--NHCOO--) and at least two (meth)acryloyl groups in the molecule. Specifically, a urethanization reaction product of a hydroxyl group-containing (meth)acrylic monomer having at least one (meth)acryloyl group and at least one hydroxyl group in the molecule and a polyisocyanate, or a polyol with a polyisocyanate It may be a urethanized reaction product of a terminal isocyanato group-containing urethane compound obtained by reacting with a (meth)acrylic monomer having at least one (meth)acryloyl group and at least one hydroxyl group in the molecule. .

The hydroxyl group-containing (meth)acrylic monomer used in the urethanization reaction can be, for example, a hydroxyl group-containing (meth)acrylate monomer, and specific examples thereof include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, ) acrylate, 2-hydroxybutyl (meth) acrylate, 2-hydroxy-3-phenoxypropyl (meth) acrylate, glycerin di (meth) acrylate, trimethylolpropane di (meth) acrylate, pentaerythritol tri (meth) acrylate, di Contains pentaerythritol penta(meth)acrylate. Specific examples other than hydroxyl group-containing (meth)acrylate monomers include N-hydroxyalkyl (meth)acrylamide monomers such as N-hydroxyethyl (meth)acrylamide and N-methylol (meth)acrylamide.

Polyisocyanates to be subjected to a urethanization reaction with a hydroxyl group-containing (meth)acrylic monomer include hexamethylene diisocyanate, lysine diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, tolylene diisocyanate, xylylene diisocyanate, and aromatic diisocyanates among these diisocyanates. Diisocyanates obtained by hydrogenating isocyanates (e.g., hydrogenated tolylene diisocyanate, hydrogenated xylylene diisocyanate, etc.), triphenylmethane triisocyanate, di- or tri-isocyanates such as dibenzylbenzene triisocyanate, and the above and polyisocyanate obtained by increasing the amount of diisocyanate.

In addition, as the polyol used for forming a terminal isocyanato group-containing urethane compound by reaction with polyisocyanate, aromatic, aliphatic or alicyclic polyol, polyester polyol, polyether polyol, etc. can be used. can. Aliphatic and cycloaliphatic polyols include 1,4-butanediol, 1,6-hexanediol, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, neopentyl glycol, trimethylolethane, trimethylolpropane, ditri Methylolpropane, pentaerythritol, dipentaerythritol, dimethylolheptane, dimethylolpropionic acid, dimethylolbutanoic acid, glycerin, hydrogenated bisphenol A and the like.

A polyester polyol is obtained by a dehydration condensation reaction between the above-described polyol and a polybasic carboxylic acid or its anhydride. Examples of polybasic carboxylic acids or their anhydrides are represented by the addition of "(anhydrous)" to what may be an anhydride: (anhydrous) succinic acid, adipic acid, (anhydrous) maleic acid, (anhydrous) Itaconic acid, (anhydrous) trimellitic acid, (anhydrous) pyromellitic acid, (anhydrous) phthalic acid, isophthalic acid, terephthalic acid, hexahydro (anhydrous) phthalic acid and the like.

The polyether polyol may be a polyoxyalkylene-modified polyol obtained by reacting the above-mentioned polyol or dihydroxybenzenes with an alkylene oxide, in addition to the polyalkylene glycol.

A polyester (meth)acrylic oligomer is a compound having an ester bond and at least two (meth)acryloyl groups (typically (meth)acryloyloxy groups) in the molecule. Specifically, it can be obtained by a dehydration condensation reaction using (meth)acrylic acid, polybasic carboxylic acid or its anhydride, and polyol. Examples of polybasic carboxylic acids or anhydrides thereof used in the dehydration condensation reaction are represented by adding "(anhydrous)" to those that can be anhydrides, such as (anhydrous) succinic acid, adipic acid, (anhydrous) maleic acid, (anhydrous) itaconic acid, (anhydrous) trimellitic acid, (anhydrous) pyromellitic acid, hexahydro (anhydrous) phthalic acid, (anhydrous) phthalic acid, isophthalic acid, terephthalic acid and the like. Polyols used in the dehydration condensation reaction include 1,4-butanediol, 1,6-hexanediol, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, neopentyl glycol, trimethylolethane, trimethylolpropane, Ditrimethylolpropane, pentaerythritol, dipentaerythritol, dimethylolheptane, dimethylolpropionic acid, dimethylolbutanoic acid, glycerin, hydrogenated bisphenol A and the like.

Epoxy (meth)acrylic oligomers can be obtained, for example, by an addition reaction between polyglycidyl ether and (meth)acrylic acid, and have at least two (meth)acryloyloxy groups in the molecule. Examples of polyglycidyl ethers used in the addition reaction include ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, tripropylene glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, bisphenol A diglycidyl ether and the like.

Although the polymerizable compound of the second adhesive may be composed only of the radically polymerizable compound, it may further contain the cationic polymerizable compound described above.

The second adhesive may be active energy ray-curable or thermosetting, but is preferably active energy ray-curable. When imparting active energy ray curability to the second adhesive, it is preferable to blend a photoradical polymerization initiator into the adhesive. A photo-radical polymerization initiator initiates a polymerization reaction of a radical-curable compound by irradiation with active energy rays such as visible light, ultraviolet rays, X-rays, or electron beams. A photoradical polymerization initiator may be used individually by 1 type, and may use 2 or more types together.

Specific examples of photoradical polymerization initiators include acetophenone, 3-methylacetophenone, benzyldimethylketal, 1-(4-isopropylphenyl)-2-hydroxy-2-methylpropan-1-one, 2-methyl-1-[ Acetophenone initiators such as 4-(methylthio)phenyl-2-morpholinopropan-1-one, 2-hydroxy-2-methyl-1-phenylpropan-1-one; benzophenone, 4-chlorobenzophenone, 4,4' - benzophenone initiators such as diaminobenzophenone; benzoin ether initiators such as benzoin propyl ether and benzoin ethyl ether; thioxanthone initiators such as 4-isopropylthioxanthone; .

The amount of the radical photopolymerization initiator to be blended is generally 0.5 to 20 parts by weight, preferably 1 to 6 parts by weight, per 100 parts by weight of the radically polymerizable compound. By blending 0.5 parts by weight or more of the radical photopolymerization initiator, the radically polymerizable compound can be sufficiently cured.

(Additive)
The first adhesive and/or the second adhesive can contain other additives as needed. Specific examples of additives include ion trapping agents, antioxidants, chain transfer agents, polymerization accelerators (such as polyols), sensitizers, sensitizing aids, light stabilizers, tackifiers, thermoplastic resins, and fillers. , flow control agents, plasticizers, antifoaming agents, leveling agents, silane coupling agents, dyes, antistatic agents, ultraviolet absorbers, and thermal polymerization initiators. A thermal polymerization initiator is used instead of a photopolymerization initiator when preparing a thermosetting adhesive. Examples of ion trapping agents include inorganic compounds such as powdery bismuth-based, antimony-based, magnesium-based, aluminum-based, calcium-based, titanium-based and mixtures thereof, and antioxidants include hindered phenol-based antioxidants. etc.

(Method for forming adhesive layer)
The first adhesive layer 150 can be directly formed on the surface of the polarizer 132 opposite to the protective layer 131 side. The first adhesive layer 150 is formed, for example, by applying the first adhesive to the surface of the polarizer 132 or the surface of the base film to be peeled off in a later step, or by applying the first adhesive between the polarizer 132 and the base film. 1 adhesive is dropped, the polarizer 132 (or the linear polarizing plate 130) and the base film are overlapped via the layer of the first adhesive before curing, and pressed from above and below using, for example, a bonding roll or the like. After lamination, it can be cured by irradiation with an active energy ray (in the case of an active energy ray-curable adhesive) or by heating and curing (in the case of a thermosetting adhesive). The active energy ray may be irradiated from the polarizing plate 130 side, or may be irradiated from the base film side.

The second adhesive layer 160 is formed by applying a second adhesive to the surface of the first adhesive layer exposed by peeling off the base film used in the step of forming the first adhesive layer 150, or to the surface of the retardation film 140. or a second adhesive is dropped between the first adhesive layer 150 and the retardation film 140, and the linear polarizing plate 130 and the retardation film 140 are attached via the uncured layer of the second adhesive. After lamination, for example, by pressing from above and below using a lamination roll or the like, it is cured by irradiating it with an active energy ray (in the case of an active energy ray-curable adhesive), or cured by heating (heat curing in the case of adhesives). The active energy ray may be applied from the linear polarizing plate 130 side or from the retardation film 140 side.

Various coating methods such as a doctor blade, wire bar, die coater, comma coater and gravure coater can be used for coating the adhesive. A method of casting an adhesive between layers to be laminated can also be adopted.

Any appropriate conditions can be adopted for the irradiation conditions of the active energy ray as long as the conditions are such that the above active energy ray-curable adhesive can be cured. For example, electron beam irradiation preferably has an acceleration voltage of 5 kV to 300 kV, 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 may result in insufficient curing. may damage the 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 insufficiently cured, and if it exceeds 100 kGy, the retardation layer will be damaged, mechanical strength will be reduced and yellowing will occur, and desired optical properties cannot be obtained.

The electron beam irradiation is usually carried out in an inert gas, but if necessary, it may be carried out in the atmosphere or under the condition that a little oxygen is introduced.

In the UV-curable adhesive, the light irradiation intensity of the active energy ray-curable adhesive is determined for each composition of the adhesive and is not particularly limited, but is preferably 10 to 1,000 mJ/cm ² . If the light irradiation intensity to the adhesive is less than 10 mJ/cm ² , the reaction time becomes too long, and if it exceeds 1,000 mJ/cm ² , the heat radiated from the light source and the heat generated during polymerization of the adhesive cause It can cause yellowing of the constituent materials of the adhesive. The irradiation intensity is preferably the intensity in the wavelength range of 400 nm or less, and more preferably the intensity in the wavelength range of 280 to 320 nm. Irradiation is performed once or more times with such light irradiation intensity, and the integrated light amount is preferably set to 10 mJ/cm ² or more, more preferably 100 to 1,000 mJ/cm ² . If the integrated amount of light to the adhesive is less than 10 mJ/cm ² , generation of active species derived from the polymerization initiator is insufficient, resulting in insufficient curing of the adhesive. On the other hand, if the integrated amount of light exceeds 1,000 mJ/cm ² , the irradiation time becomes very long, which is disadvantageous for improving productivity. At this time, which wavelength region (UVA (320 to 390 nm), UVB (280 to 320 nm), etc.) is required for the integrated amount of light differs depending on the type of film used, the combination of adhesive types, and the like.

The light source used for polymerizing and curing the adhesive by irradiating the active energy ray in the present invention is not particularly limited. Arc lamps, tungsten lamps, gallium lamps, excimer lasers, LED light sources emitting light in the wavelength range of 380 to 440 nm, chemical lamps, black light lamps, microwave excited mercury lamps, and metal halide lamps. From the viewpoint of energy stability and device simplicity, it is preferable to use an ultraviolet light source having a light emission distribution at a wavelength of 420 nm or less.

Even when an active energy ray-curable adhesive is used, heat treatment may be performed at the same time as or after the irradiation with the active energy ray. Before forming the coating layer of the adhesive, one or both of the bonding surfaces are subjected to an easy-adhesion treatment such as saponification treatment, corona discharge treatment, plasma treatment, flame treatment, primer treatment, or anchor coating treatment. may be applied.

[Phase difference]
The optical laminate 100 can function as a circularly polarizing plate by including the linear polarizing plate 130 and the retardation film 140 . Hereinafter, the configuration including the linear polarizing plate 130 and the retardation film 140 may be referred to as a circular polarizing plate.

The retardation element 140 preferably includes a first retardation layer 141 and a second retardation layer 142 . The first retardation layer 141 and the second retardation layer 142 are preferably bonded by an interlayer bonding layer 143, which will be described later. The first retardation layer 141 and the second retardation layer 142 have an overcoat layer that protects the surface thereof, and a substrate film that supports the first retardation layer 141 and the second retardation layer 142. good too. As the first retardation layer 141 and the second retardation layer 142, for example, a retardation layer giving a retardation of λ/4 (λ/4 layer), a retardation layer giving a retardation of λ/2 (λ/2 layer) and positive C layer.

The retarder 140 preferably includes a λ/4 layer, and more preferably includes at least one of a λ/4 layer and a λ/2 layer or a positive C layer.

In the retardation film 140, a first retardation layer 141 and a second retardation layer 142 are laminated in order from the polarizer 132 side. When the retarder includes λ/2 layers, the first retardation layer 141 is a λ/2 layer and the second retardation layer 142 is a λ/4 layer. When the retardation film 140 includes a positive C layer, the first retardation layer 141 is a positive C layer and the second retardation layer 142 is a λ/4 layer, or the first retardation layer 141 is a λ /4 layers, and the second retardation layer 142 is a positive C layer. The thickness of the retardation film 140 is, for example, 0.1 μm or more and 50 μm or less, preferably 0.5 μm or more and 30 μm or less, and more preferably 1 μm or more and 10 μm or less.

The retardation film 140 preferably contains a cured product of a polymerizable liquid crystal compound. In such a configuration, it may be difficult to obtain good adhesion to the polarizer 132, but according to the present invention, high adhesion can be obtained. The first retardation layer 141 of the retardation film 140 preferably contains a cured polymerizable liquid crystal compound. In such a configuration, it may be difficult to obtain good adhesion to the polarizer 132, but according to the present invention, high adhesion can be obtained. The surface of the first retardation layer 141 facing the polarizer 132 may contain a polymerizable liquid crystal compound, and may contain a cured product of a radically polymerizable liquid crystal compound as the polymerizable liquid crystal compound. In such a configuration, it may be difficult to obtain good adhesion to the polarizer 132, but according to the present invention, high adhesion can be obtained. The surface of the first retardation layer 141 facing the polarizer 132 may be the surface of a layer exhibiting retardation, or may be an alignment film.

The second retardation layer 142 may be formed from the resin film exemplified as the material of the resin film described above, or may be formed from a layer obtained by curing a polymerizable liquid crystal compound. The first retardation layer 141 and the second retardation layer 142 may further include an alignment film and a substrate film. The first retardation layer 141 having an alignment film and the second retardation layer 142 having an alignment film may be treated as one unit member.

When the first retardation layer 141 and the second retardation layer 142 are formed from a layer formed by curing a polymerizable liquid crystal compound, a composition containing a polymerizable liquid crystal compound is applied to a base film and cured. can be formed. An alignment film may be formed between the substrate film and the coating layer. The alignment film can be formed from a composition containing a polymerizable liquid crystal compound. The material and thickness of the base film may be the same as the material and thickness of the resin film. When the first retardation layer 141 and the second retardation layer 142 are formed from layers obtained by curing a polymerizable liquid crystal compound, they may be incorporated into the laminate in the form of having an alignment film and a base film.

The alignment film has an alignment control force that aligns the liquid crystal compound contained in the liquid crystal layer exhibiting the retardation formed on these alignment films in a desired direction. Examples of the alignment film include an alignment polymer film formed of an alignment polymer, a photo-alignment polymer film formed of a photo-alignment polymer, and a groove alignment film having an uneven pattern or a plurality of grooves on the film surface. can be done. The thickness of the alignment film is usually 0.01 to 10 μm, preferably 0.01 to 5 μm.

The oriented polymer film can be formed by coating a substrate film with a composition in which an oriented polymer is dissolved in a solvent, removing the solvent, and performing a rubbing treatment as necessary. In this case, the alignment regulating force can be arbitrarily adjusted by the surface state of the oriented polymer and the rubbing conditions in the oriented polymer layer formed of the oriented polymer.

A photo-alignable polymer film can be formed by applying a composition containing a polymer having a photoreactive group or a monomer and a solvent to a substrate film and irradiating polarized light. In this case, the alignment regulating force can be arbitrarily adjusted in the case of the photo-alignment polymer film by adjusting the polarized light irradiation conditions for the photo-alignment polymer.

The groove alignment film can be formed, for example, by exposing the surface of a photosensitive polyimide film through an exposure mask having pattern-shaped slits and developing the film to form an uneven pattern. A method of forming an uncured film of an energy ray-curable resin, transferring this film to a substrate film and curing it, forming an uncured layer of an active energy ray-curable resin on a substrate film, and applying Alternatively, it can be formed by a method of forming unevenness by pressing a roll-shaped master plate having unevenness and hardening it.

The liquid crystal layer exhibiting a retardation gives a predetermined retardation to light, and examples thereof include a retardation exhibiting layer in a λ/2 layer and a retardation exhibiting layer in a λ/4 layer.

A liquid crystal layer exhibiting a retardation 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. Further, the liquid crystal compound may be a polymer liquid crystal compound, a polymerizable liquid crystal compound, or a mixture thereof. As the liquid crystal compound, for example, JP-A-11-513019, JP-A-2005-289980, JP-A-2007-108732, JP-A-2010-244038, JP-A-2010-31223, JP-A-2010-31223, 2010-270108, JP-A-2011-6360, JP-A-2011-207765, JP-A-2016-81035, International Publication No. 2017/043438 and the liquid crystal compounds described in JP-A-2011-207765 is mentioned.

For example, when a polymerizable liquid crystal compound is used, a composition containing a polymerizable liquid crystal compound is applied onto an alignment film to form a coating film, and the coating film is cured to thereby exhibit a retardation liquid crystal. Layers can be formed. The thickness of the retardation layer is preferably 0.5 μm to 10 μm, more preferably 0.5 to 5 μm.
A composition containing a 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 for applying the composition containing the polymerizable liquid crystal compound include known methods such as a die coating method. As a method for curing a composition containing a polymerizable liquid crystal compound, a known method such as irradiating with an active energy ray (for example, ultraviolet rays) can be used.

The polarizing plate in which the polarizer 132 and the retardation film 140 are arranged so that the absorption axis of the polarizer 132 and the slow axis of the retardation film 140 form a predetermined angle have an antireflection function, that is, a circular shape. It can function as a polarizing plate. When the retarder 140 includes a λ/4 layer, the angle between the absorption axis of the polarizer 132 and the slow axis of the λ/4 layer can be 45°±10°. The first retardation layer 141 and the second retardation layer 142 may have normal wavelength dispersion or reverse wavelength dispersion. The λ/4 layer preferably has reverse wavelength dispersion.

[Interlayer bonding layer]
The interlayer bonding layer 143 is arranged between the first retardation layer 141 and the second retardation layer 142 and has a function of bonding the first retardation layer 141 and the second retardation layer 142 together. The interlayer bonding layer 143 can be composed of an adhesive or pressure sensitive adhesive. The interlayer bonding layer 143 is preferably an adhesive layer.

The thickness of the interlayer bonding layer 143 is not particularly limited. It may be below. When an adhesive layer is used as the interlayer bonding layer 143, the thickness of the interlayer bonding layer 143 is preferably 0.1 μm or more, may be 0.5 μm or more, and is preferably 10 μm or less. , 5 μm or less.

As the adhesive, for example, a water-based adhesive, an active energy ray-curable adhesive, or the like can be used alone or in combination of two or more. Examples of water-based adhesives include polyvinyl alcohol-based resin aqueous solutions and water-based two-liquid type urethane-based emulsion adhesives. Active energy ray-curable adhesives are adhesives that are cured by irradiation with active energy rays such as ultraviolet rays. , an adhesive containing a binder resin and a photoreactive cross-linking agent, and the like. Examples of the polymerizable compound include photopolymerizable monomers such as photocurable epoxy monomers, photocurable acrylic monomers, and photocurable urethane monomers, and oligomers derived from these monomers. Examples of the photopolymerization initiator include compounds containing substances that generate active species such as neutral radicals, anion radicals, and cation radicals upon irradiation with active energy rays such as ultraviolet rays.

The pressure-sensitive adhesive can be composed of a pressure-sensitive adhesive composition using a (meth)acrylic, rubber, urethane, ester, silicone, or polyvinyl ether resin as a base polymer. Among them, a pressure-sensitive adhesive composition using a (meth)acrylic resin as a base polymer, which is excellent in transparency, weather resistance, heat resistance, etc., is preferable. The adhesive composition may be active energy ray-curable or heat-curable.

Examples of the (meth)acrylic resin (base polymer) used in the adhesive composition include butyl (meth)acrylate, ethyl (meth)acrylate, isooctyl (meth)acrylate, and 2-(meth)acrylate. Polymers or copolymers containing one or more of (meth)acrylic acid esters such as ethylhexyl as monomers are preferably used. Preferably, the base polymer is copolymerized with a polar monomer. Examples of polar monomers include (meth)acrylic acid, 2-hydroxypropyl (meth)acrylate, hydroxyethyl (meth)acrylate, (meth)acrylamide, N,N-dimethylaminoethyl (meth)acrylate, glycidyl ( Monomers having a carboxyl group, a hydroxyl group, an amide group, an amino group, an epoxy group, etc., such as meth)acrylates, can be mentioned.

The adhesive composition can contain a cross-linking agent along with the base polymer. The cross-linking agent is a metal ion having a valence of 2 or more, which forms a carboxylic acid metal salt with a carboxyl group; a polyamine compound, which forms an amide bond with a carboxyl group; Examples include epoxy compounds and polyols that form ester bonds with carboxyl groups; and polyisocyanate compounds that form amide bonds with carboxyl groups. Among them, polyisocyanate compounds are preferred.

The active energy ray-curable pressure-sensitive adhesive composition has the property of being cured by being irradiated with an active energy ray such as an ultraviolet ray or an electron beam. It is a pressure-sensitive adhesive composition that can be adhered to an adherend such as the adhesive agent, and that can be cured by irradiation with an active energy ray to adjust the adhesion force. The active energy ray-curable pressure-sensitive adhesive composition is preferably UV-curable. The active energy ray-curable pressure-sensitive adhesive composition further contains an active energy ray-polymerizable compound in addition to the base polymer and the cross-linking agent. Furthermore, if necessary, a photopolymerization initiator, a photosensitizer, and the like may be contained.

The adhesive composition contains light diffusing agents, resins other than the base polymer, tackifiers, fillers (metal powders and other inorganic powders, etc.), antioxidants, UV absorbers, dyes, pigments, colorants, and erasers. Additives such as foaming agents, corrosion inhibitors, photoinitiators, and the like may be included.

<Method for manufacturing optical laminate>
The method for producing the optical layered body is not particularly limited. One form is a step of applying a first adhesive to the surface of the polarizer and curing the first adhesive to form a first adhesive layer, and forming the first adhesive layer on the surface of the polarizer. laminating the retardation film with a second adhesive interposed therebetween, and curing the second adhesive to form a second adhesive layer.

<Image display device>
The image display device includes an image display panel and the above optical layered body. In the image display device, the optical layered body can be arranged, for example, in front of the image display panel. The image display panel is not particularly limited, and examples thereof include a liquid crystal display panel, an organic electroluminescence (organic EL) display panel, an inorganic electroluminescence (inorganic EL) display panel, a plasma display panel, and a field emission display panel. An image display device can be configured by arranging an optical layered body functioning as a circularly polarizing plate on the viewing side of an organic EL display device.

The image display device according to the present invention can be used as mobile devices such as smartphones and tablets, televisions, digital photo frames, electronic signboards, measuring instruments and gauges, office equipment, medical equipment, computing equipment, and the like. The image display device according to the present invention has excellent durability even when used in a harsh environment.

EXAMPLES The present invention will be described in more detail below with reference to examples and comparative examples, but the present invention is not limited to these examples. In the following examples, the following were used as the radically polymerizable compound, the photoradical polymerization initiator, the cationic polymerizable compound, the photocationic polymerization initiator and the additives constituting the adhesive.

(Radical polymerizable compound)
[1] Radically polymerizable compound 1: 1,4-cyclohexanedimethanol monoacrylate (trade name “CHDMMA” obtained from Nippon Kasei Co., Ltd.)
[2] Radically polymerizable compound 2: 4-hydroxybutyl acrylate (trade name “4HBA” obtained from Nippon Kasei Co., Ltd.)
[3] Radically polymerizable compound 3: bifunctional urethane acrylate (trade name “UV-3700B” obtained from Mitsubishi Chemical Corporation)

(Photoradical polymerization initiator)
[4] Photoradical polymerization initiator 1: 1-hydroxycyclohexylphenyl ketone (trade name "Omnirad 184" obtained from BASF)
[5] Photoradical polymerization initiator 2: 2,4,6-trimethylbenzoyldiphenylphosphine oxide (trade name "TPO" obtained from BASF)

(Cationically polymerizable compound)
[6] Cationic polymerizable compound 1: 3′,4′-epoxycyclohexylmethyl 3,4-epoxycyclohexane carboxylate (trade name “CEL2021P” obtained from Daicel Corporation)
[7] Cationically polymerizable compound 2: 1,2-epoxy-4-(2-oxiranyl)cyclohexane adduct of 2,2-bis(hydroxymethyl)-1-butanol (trade name "EHPE3150")
[8] Cationic polymerizable compound 3: 3-ethyl-3-{[(3-ethyloxetan-3-yl)methoxy]methyl}oxetane (trade name "OXT-221" obtained from Toagosei Co., Ltd.)

(Photo cationic polymerization initiator)
[9] Photocationic polymerization initiator 1: Triarylsulfonium salt (trade name “CPI-100P” obtained from San-Apro Co., Ltd., 50% by weight propylene carbonate solution)

(Additive)
[10] Photosensitizer 1: 1,4-diethoxynaphthalene (trade name "Anthracure ET2201" obtained from Kawasaki Chemical Industry Co., Ltd.)
[11] Photosensitizer 2: 9,10-dibutoxyanthracene (trade name "Anthracure UVS-1331" obtained from Kawasaki Chemical Industry Co., Ltd.)

<Production Example 1: Preparation of Radical Polymerizable Adhesive>
The radically polymerizable compound and the photoradical polymerization initiator described below are weighed into a 20 mL screw tube at the mixing ratio described below, mixed and defoamed, and cured by UV irradiation Liquid radically polymerizable An adhesive was prepared. Hereinafter, this adhesive is also referred to as "adhesive R".

Radically polymerizable compound 1 25 parts by mass,
Radically polymerizable compound 2 65 parts by mass,
10 parts by mass of a radically polymerizable compound 3,
Photoradical polymerization initiator 1 3 parts by mass,
Photoradical polymerization initiator 2 1 part by mass.

<Production Example 2: Preparation of cationic polymerizable adhesive>
The cationic polymerizable compound, the photocationic polymerization initiator, and the additives described below are weighed into a 20 mL screw tube at the mixing ratio described below, mixed and degassed, and a liquid cation that cures when irradiated with ultraviolet light. A polymerizable adhesive was prepared. Hereinafter, this adhesive is also referred to as "adhesive C1".

Cationic polymerizable compound 1 32.5 parts by mass,
Cationic polymerizable compound 2 7.5 parts by mass,
Cationic polymerizable compound 3 60.0 parts by mass,
Photocationic polymerization initiator 1 2.25 parts by mass (in terms of solid content),
Photosensitizer 1 2 parts by mass.

<Production Example 3: Preparation of cationic polymerizable adhesive>
The cationic polymerizable compound, the photocationic polymerization initiator, and the additives described below are weighed into a 20 mL screw tube at the mixing ratio described below, mixed and degassed, and a liquid cation that cures when irradiated with ultraviolet light. A polymerizable adhesive was prepared. Hereinafter, this adhesive is also referred to as "adhesive C2".

Cationic polymerizable compound 1 32.5 parts by mass,
Cationic polymerizable compound 2 7.5 parts by mass,
Cationic polymerizable compound 3 60.0 parts by mass,
Photocationic polymerization initiator 1 2.25 parts by mass (in terms of solid content),
Photosensitizer 1 1 part by mass,
Photosensitizer 2 2 parts by mass.

<Preparation of adhesive layer>
A commercially available adhesive layer 1 with a separate film (a layer made of an acrylic adhesive with a thickness of 15 μm) and an adhesive layer 2 with a separate film (a layer made of an acrylic adhesive). A thickness of 5 μm) was prepared.

<Example 1: Fabrication of optical laminate>
A linear polarizing plate was produced by laminating and adhering a multilayer film to a polyvinyl alcohol (PVA) resin film (polarizer, thickness 8 μm) obtained by dyeing and stretching with iodine. A cycloolefin polymer (COP) film with HC (24 μm thick) whose hard coat layer (HC) is protected with a polyethylene terephthalate (PET) protective film is attached to a polarizer with water glue and dried to form a protective layer. A polarizer (polarizing plate) was obtained. The exposed surface of the polarizer was subjected to corona treatment, and a biaxially stretched COP film (thickness: 52 μm) was attached to the surface via an ultraviolet curable adhesive (adhesive C1). was irradiated from the biaxially stretched COP film side with a UVA power of 200 mJ/cm ² . After curing overnight at room temperature, the biaxially stretched COP film was peeled off. Thus, a linear polarizing plate having a first adhesive layer, which is a cured layer of adhesive C1, on the surface of the polarizer was obtained. Separately, prepare a retardation body (an integrated product in which a reverse dispersion λ/4 retardation layer/positive C layer/protective film (PET) is laminated), and use an adhesive R to attach the linear polarizing plate and the retardation body. and pasted together. Specifically, the exposed surface of the first adhesive layer and the exposed surface of the reverse dispersion λ/4 retardation layer are subjected to corona treatment, and the two are laminated via an ultraviolet curable adhesive (adhesive R). , UV light with a UVA intensity of 200 mJ/cm ² was irradiated from the side of the retardation film to bond the linear polarizing plate and the retardation film. As a result, the second adhesive layer, which is the cured layer of the adhesive R, was interposed between the reverse dispersion λ/4 retardation layer and the first adhesive layer (cured layer of the adhesive C1) so as to be in contact with both. An optical laminate was obtained. After that, the protective film (PET) for the retardation film in the optical laminate was peeled off, and the exposed surface of the positive C layer was subjected to corona treatment, and then the pressure-sensitive adhesive layer 1 with a separate film was attached. As described above, an optical laminate of Example 1 was obtained. In the optical laminate of Example 1, a cured layer of adhesive C1 (first adhesive layer) and a cured layer of adhesive R (second adhesive layer) is interposed.

<Comparative Example 1: Fabrication of Optical Laminate>
A comparative example was prepared in the same manner as in Example 1, except that the first adhesive layer was not formed and the adhesive C2 was used instead of the adhesive R for laminating the linear polarizing plate and the retardation film. An optical laminate of No. 1 was produced. Specifically, the formation of the cured layer of the adhesive C2 is performed by subjecting the exposed surfaces of the polarizer and the reverse dispersion λ/4 retardation layer to corona treatment, laminating the two via the adhesive C2, and then applying UV light. was irradiated from the side of the retardation film with a UVA intensity of 200 mJ/cm ² to bond the linear polarizing plate and the retardation film. The optical laminate of Comparative Example 1 has a configuration in which a cured layer of the adhesive C2 is interposed between the polarizer and the reverse-dispersive λ/4 retardation layer.

<Comparative Example 2: Fabrication of Optical Laminate>
Comparison was performed in the same manner as in Example 1 except that the first adhesive layer was not formed and the pressure-sensitive adhesive layer 2 was used instead of the adhesive R for bonding the linear polarizing plate and the retardation film. An optical laminate of Example 2 was produced. Specifically, the bonding by the adhesive layer 2 was carried out by subjecting the exposed surfaces of the polarizer and the reverse-dispersion λ/4 retardation layer to corona treatment, and laminating them with the adhesive layer 2 interposed therebetween. The optical layered body of Comparative Example 2 has a structure in which the pressure-sensitive adhesive layer 2 is interposed between the polarizer and the reverse dispersion λ/4 retardation layer.

<Measurement of tensile modulus>
Using adhesive C1, adhesive C2, and adhesive R, respectively, the adhesive was applied to a biaxially stretched COP film (thickness 52 μm), and UV light was irradiated with a UVA intensity of 200 mJ/cm ² , An adhesive layer having an average thickness of 0.3 μm after curing was formed. Each adhesive layer and the pressure-sensitive adhesive layer 2 having a thickness of 5 μm are processed using an autograph (manufactured by Shimadzu Corporation, product name: AG-IS) at a temperature of 25 ° C. at a speed of 1 mm / min. The tensile modulus was calculated from the value of the stress-strain curve obtained by uniaxial stretching. Table 1 shows the tensile modulus of each layer at a temperature of 25°C.

<Durability test (high temperature and high humidity conditions, high temperature conditions)>
Each optical laminate of Example 1, Comparative Example 1, and Comparative Example 2 was cut into a size of 30 mm × 30 mm, the separate film attached to the adhesive layer 1 was peeled off, and the alkali-free glass manufactured by Corning (product name: Eagle XG; Each sample was left for 24 hours in an oven set to high temperature and high humidity conditions (temperature 80° C., relative humidity 90% RH). The degree of polarization (Py1) at a wavelength of 550 nm before being placed in the oven and the degree of polarization (Py2) at a wavelength of 550 nm after being left in the oven for 24 hours are measured with a spectrophotometer (V-7100 manufactured by JASCO Corporation). ΔPy, which is the amount of change, was calculated based on the following formula.
ΔPy=Py2−Py1

In addition, the reflected hues (a1*, b1*) before being placed in the oven and the reflected hues (a2*, b2*) after being left in the oven for 24 hours were measured by placing the sample on a metal reflector and carrying it. Measured with a spectrophotometer (manufactured by Konica Minolta, product name: CM-2600d), and Δc*, which is the amount of change, was calculated based on the following formula.
Δc*=√{(a2*−a1*) ² +(b2*−b1*) ² }

Each sample was left in an oven set to high temperature conditions (temperature 105° C., relative humidity 0% RH) for 30 minutes, and Δc* was calculated in the same manner as in the high temperature and high humidity conditions described above.

Table 2 shows the calculated values of ΔPy and Δc*.

<Adhesion test>
Each optical laminate of Example 1, Comparative Example 1, and Comparative Example 2 was cut into a size of 30 mm × 30 mm, the separate film attached to the adhesive layer 1 was peeled off, and the alkali-free glass manufactured by Corning (product name: Eagle XG; After peeling off the COP film with HC on the outermost surface of each sample, a cutter knife was used to make cross-cuts at intervals of 1 mm in an area of 10 mm×10 mm to prepare 10×10 (100) squares. Cellotape (registered trademark) manufactured by Nichiban Co., Ltd. was affixed so as to be in contact with all the squares, adhered well, and peeled off at once at an oblique upward angle of 45 degrees. By this operation, the number of remaining masses remaining on the glass side was counted. Table 2 shows the number of remaining squares.

REFERENCE SIGNS LIST 100 optical laminate, 130 linear polarizing plate, 131 protective layer, 132 polarizer, 140 retardation element, 141 first retardation layer, 142 second retardation layer, 143 interlayer bonding layer.

Claims (8)

An optical laminate having a polarizer containing a polyvinyl alcohol-based resin and a retardation film containing a cured product of a polymerizable liquid crystal compound,
An optical optical system comprising a first adhesive layer provided in contact with the polarizer and a second adhesive layer provided in contact with the retardation element, between the polarizer and the retardation element. laminate. The first adhesive layer has a tensile modulus of 2000 MPa or more at a temperature of 25° C.,
The optical laminate according to claim 1, wherein the second adhesive layer has a tensile modulus of 1900 MPa or less at a temperature of 25°C. The first adhesive layer is a cured product layer of a cationic polymerizable adhesive,
3. The optical laminate according to claim 1, wherein the second adhesive layer is a cured product layer of a radically polymerizable adhesive. The optical laminate according to any one of claims 1 to 3, wherein the retardation film includes a λ/4 layer. 5. The optical laminate according to claim 1, which is an antireflection polarizing plate. An image display device comprising an image display panel and the optical layered body according to claim 5 arranged in front of the image display panel. 7. The image display device according to claim 6, wherein said image display panel is an organic EL display panel. A method for producing an optical laminate according to any one of claims 1 to 5,
applying a first adhesive to the surface of the polarizer and curing the first adhesive to form a first adhesive layer;
The first adhesive layer formed on the surface of the polarizer and the retardation film are laminated with a second adhesive interposed therebetween, and the second adhesive is cured to form a second adhesive layer. A method for manufacturing an optical layered body, comprising:

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