WO2021132236A1 - Optical laminate - Google Patents

Abstract

[Abstract] [Problem] To provide an optical laminate capable of preventing, even in a high-temperature and high-humidity environment, the deterioration of a conductive layer due to the migration of a dichroic dye included in a polarizer to the conductive layer because the movement of the dichroic dye from the polarizer is particularly dominant in the high-temperature and high-humidity environment. [Solution] This optical laminate includes a polarizer, a first cured product layer, a retardation layer, and an adhesive layer, in this order, wherein: the polarizer is composed of a polyvinyl alcohol resin including iodine; the first cured product layer is a cured product of an active energy curable composition; the retardation layer includes at least one retardation expression layer which is a polymer of a polymerizable liquid crystal compound; the adhesive layer has an iodine content of 900 mg/kg after the optical laminate is stored for 250 hours at a temperature of 80 °C and a relative humidity of 90%; the polarizer and the first cured product layer are in direct contact with each other; and the first cured product layer and the retardation layer are in direct contact with each other. [Selected drawing] FIG. 1

Description

Optical laminate

The present invention relates to an optical laminate.

In the image display device, a method is adopted in which an optical laminate having antireflection performance is arranged on the visual side of the image display panel to suppress deterioration of visibility due to reflection of external light.

As an optical laminate having antireflection performance, a circular polarizing plate having a structure in which a linear polarizing plate having a thermoplastic resin film on both sides of a polarizing element and a retardation layer are laminated via an adhesive layer is known. (Patent Document 1). The circularly polarizing plate is usually provided with an adhesive layer on the side opposite to the linearly polarized light of the retardation layer, and is laminated on the image display panel.

Further, in recent years, in image display devices, input devices that use a combination of a circularly polarizing plate and an image display panel having a touch panel function have become widespread. A transparent conductive film such as an indium tin oxide (ITO) thin film or a conductive layer made of a metal layer such as aluminum is formed on the surface of an image display panel having a touch panel function.

JP-A-2019-197235

In recent years, with the thinning of image display devices, circular polarizing plates to which a linear polarizing plate having a thermoplastic resin film is provided on only one side of a polarizing element have been proposed. When a linear polarizing plate having such a configuration is laminated on the conductive layer, the dichroic dye (for example, iodine) contained in the polarizer may move to the conductive layer, which may cause a malfunction such as poor detection. There is. Since the movement of the dichroic dye from the polarizer is particularly remarkable in a high temperature and high humidity environment, the dichroic dye contained in the polarizing element is transferred to the conductive layer even in a high temperature and high humidity environment. There is a need for an optical laminate that can prevent deterioration of the conductive layer due to the above.

The present invention provides the following [1] to [16].
[1] An optical laminate including a polarizer, a first cured product layer, a retardation layer, and an adhesive layer in this order.
The polarizer is made of a polyvinyl alcohol resin containing iodine.
The first cured product layer is a cured product of an active energy curable composition.
The retardation layer contains at least one retardation expression layer which is a polymer of a polymerizable liquid crystal compound.
The pressure-sensitive adhesive layer has an iodine content of 900 mg / kg or less after the optical laminate is stored at a temperature of 80 ° C. and a relative humidity of 90% for 250 hours.
The polarizer and the first cured product layer are in direct contact with each other.
An optical laminate in which the first cured product layer and the retardation layer are in direct contact with each other.
[2] The retardation layer is a layer containing the first polymerized layer, the second cured product layer, and the second polymerized layer in this order from the first cured product layer side.
The optical laminate according to [1], wherein the first polymerized layer and the second polymerized layer contain a polymer of a polymerizable liquid crystal compound independently of each other.
[3] The optical laminate according to [2], wherein the second cured product layer is an active energy ray-cured product layer.
[4] Temperature 80 ° C. and 90% relative humidity moisture permeability of the first cured layer in a thickness 30μm is ^{1500 [g / (m 2 ·} 24hr)] Hereinafter, according to any one of [1] to [3] Optical laminate.
[5] An optical laminate including a polarizer, a first cured product layer, a first retardation layer, a second cured product layer, a second retardation layer, and an adhesive layer in this order.
The polarizer is made of a polyvinyl alcohol resin containing iodine.
The first retardation layer and the second retardation layer contain a retardation expression layer containing a polymer of a polymerizable liquid crystal compound independently of each other.
The first cured product layer and the second cured product layer contain the cured product of the active energy ray-curable composition independently of each other.
The storage elastic modulus of the first cured product layer at a temperature of 80 ° C. is 300 MPa or more.
The polarizer and the first cured product layer are in direct contact with each other.
An optical laminate in which the first cured product layer and the first retardation layer are in direct contact with each other.
[6] The optical laminate according to [5], wherein the second cured product layer has a storage elastic modulus of 20 MPa or more at a temperature of 80 ° C.
[7] The storage elastic modulus (E ₁ ) of the first cured product layer at a temperature of 80 ° C. is _{larger than the storage elastic modulus (E 2} ) of the second cured product layer at a temperature of 80 ° C., [5] or [6]. ] The optical laminate according to.
[8] Temperature 80 ° C. and 90% relative humidity moisture permeability of the first cured layer in a thickness 30μm is ^{1500 [g / (m 2 ·} 24hr)] Hereinafter, according to any one of [5] to [7] Optical laminate.
[9] An optical laminate including a polarizer, a first cured product layer, a first retardation layer, a second cured product layer, a second retardation layer, and an adhesive layer in this order.
The polarizer is made of a polyvinyl alcohol resin containing iodine.
The first retardation layer and the second retardation layer contain a retardation expression layer which is a polymer of a polymerizable liquid crystal compound independently of each other.
The first cured product layer and the second cured product layer are independently cured products of an active energy ray-curable composition.
The glass transition temperature (Tg ₁ ) of the first cured product layer is more than 60 ° C.
The polarizer and the first cured product layer are in direct contact with each other.
An optical laminate in which the first cured product layer and the first retardation layer are in direct contact with each other.
[10] The optical laminate according to [9], wherein the glass transition temperature (Tg _{2) of the second cured product layer is 40 ° C. or higher.}
[11] The optical laminate according to [9] or [10], wherein the glass transition temperature (Tg ₁ ) of the first cured product layer is _{higher than the glass transition temperature (Tg 2) of the second cured product layer.}
[12] Temperature 80 ° C. and 90% relative humidity moisture permeability of the first cured layer in a thickness 30μm is ^{1500 [g / (m 2 ·} 24hr)] Hereinafter, according to any one of [9] to [11] Optical laminate.
[13] An optical laminate including a polarizer, a first cured product layer, a retardation layer, and an adhesive layer in this order.
The polarizer is made of a polyvinyl alcohol resin containing iodine.
The retardation layer includes a retardation expression layer containing a polymer of a polymerizable liquid crystal compound.
The first cured product layer is a cured product of an active energy curable composition.
The active energy ray-curable composition is an optical laminate containing an epoxy compound (A2-1) containing a tricyclic condensed ring and two glycidyl ether groups in the molecule.
[14] An optical laminate including a polarizer, a first cured product layer, a first retardation layer, a second cured product layer, a second retardation layer, and an adhesive layer in this order.
The polarizer is made of a polyvinyl alcohol resin containing iodine.
The one cured product layer is a cured product of an active energy curable composition.
The active energy ray-curable composition is an optical laminate containing an epoxy compound (A2-1) containing a tricyclic condensed ring and two glycidyl ether groups in the molecule.
[15] An active energy ray-curable composition containing a curable component (A) and a photopolymerization initiator (B).
The curable component (A) contains a polyfunctional oxetane compound (A5-1) and an epoxy compound (A2-1) containing a tricyclic condensed ring and a diglycidyl ether group in the molecule.
Active energy rays in which the content of the polyfunctional oxetane compound (A5-1) is higher than the content of the epoxy compound (A2-1) containing the tricyclic condensed ring and two glycidyl ether groups in the molecule. Curable composition.
[16] The content ratio (mass ratio) of the polyfunctional oxetane compound (A5-1) to the epoxy compound (A2-1) containing the tricyclic condensed ring and two glycidyl ether groups in the molecule is determined. The polyfunctional oxetane compound (A5-1) / epoxy compound (A2-1) containing the tricyclic condensed ring and two glycidyl ether groups in the molecule = 1.5 / 1 to 5/1 [ 15] The active energy ray-curable composition according to.

The optical laminate of the present invention is a laminate provided with a linear polarizing plate and a retardation layer, and can suppress corrosion of the conductive layer when laminated with the conductive layer via an adhesive layer.

It is the schematic sectional drawing which shows typically the laminated body of this invention. It is the schematic sectional drawing which shows typically the retardation layer. It is the schematic cross-sectional view which shows typically an example of each manufacturing process in the manufacturing method of a laminated body.

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 is appropriately adjusted to make it easier to understand each component, 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 of the present invention will be described with reference to FIG. The optical laminate 100 shown in FIG. 1 includes a polarizer 13, a first cured product layer 14, a retardation layer 20, and an adhesive layer 70 in this order, and the polarizer 13 and the first cured product layer 14 are in direct contact with each other. , The first cured product layer 14 and the retardation layer 20 are in direct contact with each other. The thermoplastic resin film 11 may be laminated on the side of the polarizer 13 opposite to the first cured product layer 14 via the adhesive layer 12. Further, it is preferable that the retardation layer 20 and the pressure-sensitive adhesive layer 70 are in direct contact with each other. In the present invention, the configuration including the thermoplastic resin film 11, the adhesive layer 12, and the polarizer 13 in this order is referred to as a linear polarizing plate 10.

Although not shown, a known surface treatment layer such as a hard coat layer or an antireflection layer may be provided on the opposite side of the thermoplastic resin film 11 from the adhesive layer 12. The thickness of the optical laminate 100 may be, for example, 2 μm or more and 100 μm, preferably 2 μm or more and 80 μm or less.

The optical laminate 100 may be long or single-wafered. When the optical laminate 100 has a single-wafer shape, the shape of the optical laminate 100 in a plan view can be substantially rectangular. The plan view means that the optical laminate 100 is viewed from the thickness direction. A substantially rectangular shape means a shape in which at least one of the four corners (corners) is cut off so as to have an obtuse angle, a shape having a rounded shape, or a part of an end face in a plan view. Has a recess (notch) that is recessed in the in-plane direction, or has a perforated part that is hollowed out into a shape such as a circle, an ellipse, a polygon, or a combination thereof in a plan view. It means that you can do it.

The size of the optical laminate 100 is not particularly limited. When the optical laminate 100 is single-wafered and substantially rectangular, the length of the long side is preferably 6 cm or more and 35 cm or less, more preferably 10 cm or more and 30 cm or less, and the length of the short side. The size is preferably 5 cm or more and 30 cm or less, and more preferably 6 cm or more and 25 cm or less.

(Thermoplastic resin film)
The thermoplastic resin film 11 can be arranged on the visible side of the laminate. The thermoplastic resin film 11 can have the function of a protective film for protecting the polarizer 13. Although not shown, the thermoplastic resin film may be arranged on both sides of the polarizer, but from the viewpoint of thinning the laminate, the thermoplastic resin film may be arranged on one side of the polarizer. Preferably, it is more preferably arranged only on the visible side of the laminate.

The material of the thermoplastic resin film 11 is not particularly limited, but for example, a cyclic polyolefin resin film, a cellulose acetate resin film made of a resin such as triacetyl cellulose or diacetyl cellulose, polyethylene terephthalate, or polyethylene na. Examples of films known in the art include polyester resin films made of resins such as phthalate and polybutylene terephthalate, polycarbonate resin films, (meth) acrylic resin films, and polypropylene resin films. From the viewpoint of thinning, the thickness of the thermoplastic resin film 11 is usually 300 μm or less, preferably 200 μm or less, more preferably 50 μm or less, and usually 5 μm or more, 20 μm or more. Is preferable. Further, the thermoplastic resin film 11 may or may not have a phase difference.

The thermoplastic resin film 11 contains rubber particles, lubricants, fluorescent whitening agents, dispersants, heat stabilizers, light stabilizers, ultraviolet absorbers, infrared absorbers, antistatic agents, antioxidants, etc., as required. The additive may be contained alone or in combination of two or more. The thermoplastic resin film 11 preferably contains an ultraviolet absorber from the viewpoint of durability (light resistance) of the laminated body.

The thermoplastic resin film 11, from the viewpoint of corrosion resistance, moisture permeability is preferably not more than 100g ^/ m 2 · 24hr, and more preferably less ^30g / m 2 · 24hr.

(Adhesive layer)
The adhesive layer 12 is a layer formed of an adhesive for adhering the thermoplastic resin film 11 and the polarizer 13. The adhesive may be any adhesive that exhibits adhesive strength to both of them. For example, an aqueous adhesive in which an adhesive component is dissolved or dispersed in water, or an active energy ray-curable compound containing an active energy ray-curable compound. Examples include mold adhesive compositions.

As the water-based adhesive composition, for example, a polyvinyl alcohol-based resin or a urethane resin is used as a main component, and a cross-linking agent or a curable compound such as an isocyanate-based compound or an epoxy compound is blended in order to improve adhesion. Can be a thing.

When a polyvinyl alcohol-based resin is used as the main component of the aqueous adhesive composition, in addition to partially saponified polyvinyl alcohol and fully saponified polyvinyl alcohol, carboxyl group-modified polyvinyl alcohol, acetoacetyl group-modified polyvinyl alcohol, methylol group-modified polyvinyl alcohol, etc. And modified polyvinyl alcohol-based resins such as amino group-modified polyvinyl alcohol may be used. The water-based adhesive composition preferably contains an acetoacetyl group-modified polyvinyl alcohol. Such an aqueous solution of 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 part by mass or more and 10 parts by mass or less with respect to 100 parts by mass of water. It is preferably 1 part by mass or more and 5 parts by mass or less.

A curable compound such as a polyvalent aldehyde, a water-soluble epoxy resin, a melamine compound, a zirconia compound, and a zinc compound is added to an aqueous adhesive composition composed of an aqueous solution of a polyvinyl alcohol resin in order to improve adhesion. Can be blended. To give an example of a water-soluble epoxy resin, a water-soluble epoxy resin obtained by reacting a polyamide polyamine obtained by reacting a polyalkylene polyamine such as diethylenetriamine or triethylenetetramine with a dicarboxylic acid such as adipic acid with epichlorohydrin. There is a sex polyamide epoxy resin. As commercially available products of such polyamide epoxy resin, "Sumirace Resin 650" and "Sumiraizu Resin 675" sold by Sumika Chemtex Co., Ltd., "WS-525" sold by Japan PMC Co., Ltd., etc. There is. When the water-soluble epoxy resin is blended, the amount added is usually 1 part by mass or more and 100 parts by mass or less, preferably 1 part by mass or more and 50 parts by mass or less with respect to 100 parts by mass of the polyvinyl alcohol-based resin.

When urethane resin is used as the main component of the water-based adhesive composition, it is effective to use polyester-based ionomer-type urethane resin as the main component of the water-based adhesive composition. The polyester-based ionomer type urethane resin referred to here is a urethane resin having a polyester skeleton, in which a small amount of an ionic component (hydrophilic component) is introduced. Since such an ionomer type urethane resin is directly emulsified in water to form an emulsion without using an emulsifier, it can be used as an aqueous adhesive. When a polyester ionomer type urethane resin is used, it is effective to add a water-soluble epoxy compound as a cross-linking agent. Using a polyester-based ionomer type urethane resin as an adhesive for a polarizing plate is described in, for example, Japanese Patent Application Laid-Open No. 2005-70140 and Japanese Patent Application Laid-Open No. 2005-208456.

The water-based adhesive composition can contain a filler, a flow conditioner, a defoaming agent, a leveling agent, a dye, an organic solvent and the like.

The water-based adhesive composition is usually used in the form of each component dissolved in water. The components contained in the water-based adhesive composition that are insoluble in water may be dispersed in the system. A transparent pressure-sensitive adhesive may be formed by applying the water-based adhesive composition to one side of the polarizer and drying it.

The water-based adhesive composition is applied to one or both sides of a polarizer or a thermoplastic resin film, and then bonded to each other. Then, the water is evaporated by heating and the thermal cross-linking reaction is allowed to proceed to sufficiently bond the two. can do. A laminate in which the polarizer 13 and the thermoplastic resin film 11 are laminated via the adhesive layer 12 is also referred to as a linear polarizing plate 10.

Regarding the active energy ray-curable adhesive composition, the description in the first cured product layer 14 described later is applied. The active energy ray-curable adhesive composition used for the adhesive layer 12 may not contain either a photosensitizer or a photosensitizer. Further, the type may be the same as or different from the active energy ray-curable adhesive composition contained in the first cured product layer 14.

The thickness of the first adhesive layer 12 may be, for example, 20 μm or less, preferably 10 μm or less, and more preferably 5 μm or less. The thickness of the first adhesive layer 12 may be, for example, 0.1 μm or more.

(Polarizer)
The polarizer 13 is an absorption type polarizer having a property of absorbing linearly polarized light having a vibration plane parallel to its absorption axis and transmitting linearly polarized light having a vibration plane orthogonal to the absorption axis (parallel to the transmission axis). Can be. As the polarizer 13, a polarizer in which a dichroic dye is adsorbed and oriented on a uniaxially stretched polyvinyl alcohol-based resin film can be preferably used. The polarizer 13 is, for example, a step of uniaxially stretching a polyvinyl alcohol-based resin film; a step of adsorbing a dichroic dye by dyeing the polyvinyl alcohol-based resin film with a dichroic dye; polyvinyl having the dichroic dye adsorbed. It can be produced by a method including a step of treating the alcohol-based resin film with a cross-linking solution such as an aqueous boric acid solution; and a step of washing with water after the treatment with the cross-linking solution.

As the polyvinyl alcohol-based resin, a saponified polyvinyl acetate-based resin can be used. Examples of the polyvinyl acetate-based resin include polyvinyl acetate, which is a homopolymer of vinyl acetate, and a copolymer of vinyl acetate and another monomer copolymerizable with the vinyl acetate. Examples of other monomers copolymerizable with vinyl acetate include unsaturated carboxylic acids, olefins, vinyl ethers, unsaturated sulfonic acids, and (meth) acrylamides having an ammonium group.

As used herein, the term "(meth) acrylic" means at least one selected from acrylic and methacryl. The same applies to "(meth) acryloyl", "(meth) acrylate" and the like.

The degree of saponification of the polyvinyl alcohol-based resin is usually 85 to 100 mol%, preferably 98 mol% or more. The polyvinyl alcohol-based resin may be modified, and for example, polyvinyl formal or polyvinyl acetal modified with aldehydes can be used. The average degree of polymerization of the polyvinyl alcohol-based resin is usually 1000 to 10000, preferably 1500 to 5000. The average degree of polymerization of the polyvinyl alcohol-based resin can be determined in accordance with JIS K 6726.

A film formed of such a polyvinyl alcohol-based resin is used as a raw film for a polarizer. The method for forming a film of the polyvinyl alcohol-based resin is not particularly limited, and a known method is adopted. The thickness of the polyvinyl alcohol-based raw film is not particularly limited, but may be, for example, 5 μm or more and 85 μm or less.

The uniaxial stretching of the polyvinyl alcohol-based resin film can be performed before dyeing the dichroic dye, at the same time as dyeing, or after dyeing. If the uniaxial stretching is performed after staining, the uniaxial stretching may be performed before or during the cross-linking treatment. Moreover, uniaxial stretching may be performed in these a plurality of steps.

In uniaxial stretching, rolls having different peripheral speeds may be uniaxially stretched, or thermal rolls may be used to uniaxially stretch. The uniaxial stretching may be a dry stretching in which the film is stretched in the atmosphere, or a wet stretching in which the polyvinyl alcohol-based resin film is swollen with a solvent or water. The draw ratio is usually 3 to 8 times.

As a method of dyeing a polyvinyl alcohol-based resin film with a dichroic dye, for example, a method of immersing the film in an aqueous solution containing a dichroic dye is adopted. As the dichroic dye, iodine or a dichroic organic dye is used. The polyvinyl alcohol-based resin film is preferably immersed in water before the dyeing treatment.

As the cross-linking treatment after dyeing with a dichroic dye, a method of immersing the dyed polyvinyl alcohol-based resin film in a boric acid-containing aqueous solution is usually adopted. When iodine is used as the dichroic pigment, the boric acid-containing aqueous solution preferably contains potassium iodide.

The thickness of the polarizer 13 is usually 30 μm or less, preferably 28 μm or less, more preferably 20 μm or less, still more preferably 15 μm or less, and particularly preferably 10 μm or less. The thickness of the polarizer 13 is usually 2 μm or more, preferably 3 μm or more.

(First cured product layer)
The first cured product layer 14 is formed with the polarizer 13 and the retardation layer 20 in order to bond the polarizing element 13 and the retardation layer 20 (to bond the linear polarizing plate and the retardation laminate described later). Placed between. The first cured product layer 14 is a cured product of the active energy ray-curable adhesive composition. By forming the first cured product layer 14 from the cured product of the active energy ray-curable adhesive composition, the transfer of iodine contained in the polarizer is suppressed as compared with the case where the pressure-sensitive adhesive layer is used, and the conductive layer and the conductive layer Corrosion of the conductive layer when laminated can be suppressed. In the present invention, the evaluation of corrosiveness is performed according to the evaluation method described in the column of Examples described later.

The thickness of the first cured product layer 14 may be, for example, 10 μm or less, preferably 5 μm or less, more preferably 4 m or less, and further preferably 3 μm or less. The thickness of the first cured product layer 14 may be, for example, 0.5 μm or more, preferably 1 μm or more.

(Active energy ray-curable adhesive composition)
The active energy ray-curable adhesive composition may be any one that is cured by irradiating with active energy rays, for example, a cationically polymerizable adhesive composition, or a radically polymerizable adhesive composition. There may be. The active energy ray-curable adhesive composition is preferably a cationically polymerizable adhesive composition.

(Cationopolymerizable Adhesive Composition)
The cationically polymerizable adhesive composition contains a curable component (A) and a photocationic polymerization initiator (B). The curable component (A) is a component that can be cured by causing cationic polymerization by irradiation with active energy rays. Adhesive strength is developed by polymerization curing of the curable component (A).

(Curable component (A))
The curable component (A) can contain at least one of an alicyclic epoxy compound (A1) and a polyfunctional aliphatic epoxy compound (A2). The curable component (A) can further include at least one selected from the group consisting of a monofunctional epoxy compound (A3), a polyfunctional aromatic epoxy compound (A4) and an oxetane compound (A5).

When the curable component (A) contains an alicyclic epoxy compound (A1), the content of the alicyclic epoxy compound (A1) is, for example, 5 parts by mass or more and 90 parts by mass with respect to 100 parts by mass of the curable component (A). It may be 10 parts by mass or less, preferably 10 parts by mass or more and 80 parts by mass or less.
When the curable component (A) contains the polyfunctional aliphatic epoxy compound (A2), the content of the polyfunctional aliphatic epoxy compound (A2) is, for example, 1 part by mass with respect to 100 parts by mass of the curable component (A). It may be 50 parts by mass or less, preferably 5 parts by mass or more and 45 parts by mass or less.
When the curable component (A) contains the monofunctional epoxy compound (A3), the content of the monofunctional epoxy compound (A3) is, for example, 1 part by mass or more and 20 parts by mass with respect to 100 parts by mass of the curable component (A). It may be less than or equal to, preferably 1 part by mass or more and 15 parts by mass or less.
When the curable component (A) contains the polyfunctional aromatic epoxy compound (A4), the content of the polyfunctional aromatic epoxy compound (A4) is, for example, 1 part by mass with respect to 100 parts by mass of the curable component (A). It may be 60 parts by mass or less, preferably 1 part by mass or more and 50 parts by mass or less.
When the curable component (A) contains the oxetane compound (A5), the content of the oxetane compound (A5) is, for example, 5 parts by mass or more and 90 parts by mass or less with respect to 100 parts by mass of the curable component (A). It is often, preferably 10 parts by mass or more and 80 parts by mass or less.

The active energy ray-curable adhesive composition preferably does not contain a solvent. Hereinafter, each component will be described in detail.

(Alicyclic epoxy compound (A1))
The alicyclic epoxy compound (A1) is a compound having one or more alicyclic epoxy groups. The alicyclic epoxy compound (A1) may further have an epoxy group other than the alicyclic epoxy group as long as it is a compound having one or more alicyclic epoxy groups. In the present specification, the alicyclic epoxy group means an epoxy group bonded to the alicyclic ring, and means a bridging oxygen atom-O-in the structure represented by the following formula (a).

In the above formula (a), m is an integer of 2 to 5. The compound in which the group in the form of removing one or a plurality of hydrogen atoms _{in (CH 2} ) _m in the above formula (a) is bonded to another chemical structure can be an alicyclic epoxy compound (A1). .. One or more hydrogen atoms in (CH ₂ ) _m may be appropriately substituted with a linear alkyl group such as a methyl group or an ethyl group. The curing rate of the active energy ray-curable adhesive composition can be adjusted by the alicyclic epoxy compound (A1).

Specific examples of the alicyclic epoxy compound (A1) include 3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexanecarboxylate, 1,2-epoxy-4-vinylcyclohexane, and 1,2-epoxy-1-methyl-. 4- (1-Methylepoxyethyl) cyclohexane, 3,4-epoxycyclohexylmethyl methacrylate, 4- (1,2-epoxyethyl) -1,2-of 2,2-bis (hydroxymethyl) -1-butanol Epoxycyclohexane adduct, ethylene bis (3,4-epoxycyclohexanecarboxylate), oxydiethylene bis (3,4-epoxycyclohexanecarboxylate), 1,4-cyclohexanedimethylbis (3,4-epoxycyclohexanecarboxylate), And 3- (3,4-epoxycyclohexanemethoxycarbonyl) propyl 3,4-epoxycyclohexanecarboxylate and the like.

Among the alicyclic epoxy compounds (A1), 3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexanecarboxylate is preferably used because it has appropriate curability and can be obtained at a relatively low price. As the alicyclic epoxy compound (A1), one kind of alicyclic epoxy compound may be used alone, or a plurality of different kinds may be used in combination.

Commercially available products can be used as the alicyclic epoxy compound (A1). For example, the "Ceroxide (registered trademark)" series and "Cyclomer (registered trademark)" sold by Daicel Co., Ltd. under their respective trade names. , "Cyracure UVR" series sold by Dow Chemical Co., Ltd., etc.

(Polyfunctional aliphatic epoxy compound (A2))
The polyfunctional aliphatic epoxy compound (A2) is a compound having two or more epoxy groups and having no aromatic ring. However, the polyfunctional aliphatic epoxy compound (A2) referred to in the present specification excludes compounds having an alicyclic epoxy group contained in the alicyclic epoxy compound (A1). The adhesiveness of the adhesive cured layer can be adjusted by the polyfunctional aliphatic epoxy compound (A2).

As the polyfunctional aliphatic epoxy compound (A2), an aliphatic diepoxy compound represented by the following formula (b) is more preferable. By containing the aliphatic diepoxy compound represented by the following formula (b) as the polyfunctional aliphatic epoxy compound (A2), an active energy ray-curable adhesive having a low viscosity and easy to apply can be obtained.

Wherein (b), Z is an alkylene group, an alkylidene group having 3 or 4 carbon atoms having 1 to 9 carbon atoms, a divalent alicyclic hydrocarbon group, or the formula ^{_{-C m H 2m -Z 1 -C n}} H It is a divalent group represented by _{2n −.} Further, the formula ^{_{-C m H 2m -Z 1 -C n}} H 2n - ^in, -Z 1 - is, -O -, - CO-O -, - O-CO -, - SO 2 -, - SO- Alternatively, it is CO-, and m and n each independently represent an integer of 1 or more, and the sum of m and n is 9 or less.

The divalent alicyclic hydrocarbon group may be, for example, a divalent alicyclic hydrocarbon group having 4 to 16 carbon atoms, for example, a divalent group represented by the following formula (b-1) or a formula. Examples thereof include a divalent group represented by (b-2).

Specific examples of the compound represented by the formula (b) include diglycidyl ether of alkanediol, diglycidyl ether of oligoalkylene glycol up to about 4 repetitions, diglycidyl ether of alicyclic diol and the like.

Examples of the diol (glycol) capable of forming the compound represented by the formula (b) include ethylene glycol, propylene glycol, 1,3-propanediol, 2-methyl-1,3-propanediol, and 2-butyl-. 2-Ethyl-1,3-propanediol, 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-Pentanediol, 2,4-diethyl-1,5-Pentanediol, 1,6-Hexanediol, 1,7-Heptanediol, 3,5- Alcandiols such as heptanediol, 1,8-octanediol, 2-methyl-1,8-octanediol and 1,9-nonanediol; oligoalkylene glycols such as diethylene glycol, triethylene glycol, tetraethylene glycol and dipropylene glycol Examples thereof include alicyclic diols such as cyclohexanediol, cyclohexanedimethanol, and dicyclopentadienedimethanol.

In the present invention, the polyfunctional aliphatic epoxy compound (A2) includes 1,4-butanediol diglycidyl ether, from the viewpoint of obtaining an active energy ray-curable adhesive composition having a low viscosity and easy to apply. 1,6-Hexanediol diglycidyl ether, neopentyl glycol diglycidyl ether, and dicyclopentadiene methanol diglycidyl ether are preferable.
As the polyfunctional aliphatic epoxy compound (A2), one kind of aliphatic epoxy compound may be used alone, or a plurality of different kinds may be used in combination.

Further, as a uniform state of the present invention, the polyfunctional aliphatic epoxy compound (A2) is preferably an epoxy compound (A2-1) containing a tricyclic condensed ring and two glycidyl ether groups in the molecule. ..
The tricyclic condensed ring is not particularly limited as long as it is a condensed ring composed of three rings, but a condensed ring composed of an aliphatic ring is preferable. Examples of the tricyclic fused ring include an adamantane ring, a tricyclodecane ring, a dicyclopentadiene ring, and a tricyclodecanene ring.
Examples of the epoxy compound (A2-1) containing a tricyclic condensed ring and two glycidyl ether groups in the molecule include a compound represented by the following formula (c-1).

[In formula (c-1), X ₁ represents a tricyclic condensed ring, and Z ² and Z ³ each independently represent a single bond or a divalent hydrocarbon group. ]
Examples of the tricyclic condensed ring represented by X ₁ include an adamantane ring, a tricyclodecane ring, a dicyclopentadiene ring, a tricyclodecane ring, and the like, and a tricyclodecane ring is preferable.
Examples of the divalent hydrocarbon group represented by Z ² and Z ³ include an alkanediyl group having 1 to 8 carbon atoms such as a methylene group, an ethylene group and a propanediyl group; and a phenylene group having 6 to 10 carbon atoms. Aromatic hydrocarbon groups of.
Z ² and Z ³ are preferably divalent hydrocarbon groups independently of each other, more preferably an alkanediyl group having 1 to 8 carbon atoms, and an alkanediyl group having 1 to 4 carbon atoms. More preferably, it is particularly preferably a methylene group.

Commercially available products can be used as the polyfunctional aliphatic epoxy compound (A2), for example, "EP-4088S" (above, manufactured by ADEKA Corporation), "EHPE3150" (above, manufactured by Daicel Corporation), "EX". -211L "," EX-212L "(all of which are manufactured by Nagase ChemteX Corporation) and the like can be mentioned.

(Monofunctional epoxy compound (A3))
The monofunctional epoxy compound (A3) is a compound having one epoxy group. However, the monofunctional epoxy compound (A3) referred to in the present specification excludes compounds having an alicyclic epoxy group in the molecule contained in the alicyclic epoxy compound (A1). The monofunctional epoxy compound (A3) may or may not have an aromatic ring in the molecule. The viscosity of the active energy ray-curable adhesive composition can be adjusted by the monofunctional epoxy compound (A3).

Examples of the monofunctional epoxy compound (A3) having an aromatic ring include monovalent phenols such as phenol, cresol, and butylphenol, bisphenol A, bisphenol derivatives such as bisphenol F, and monoglycidyl esterified products of their alkylene oxide adducts; epoxy novolac. Resin: Monoglycidyl esterified product of an aromatic compound having two or more phenolic hydroxyl groups such as resorcinol, hydroquinone, and catechol; an aromatic compound having two or more alcoholic hydroxyl groups such as benzenedimethanol, benzenediethanol, and benzenedibutanol. Monoglycidyl esterified products; monoglycidyl esters of polybasic acid aromatic compounds having two or more carboxyl groups such as phthalic acid, terephthalic acid, trimellitic acid; glycidyl esters of benzoic acid, toluic acid, monoglycidyl naphthoic acid Esters and the like can be mentioned.

Examples of the monofunctional epoxy compound (A3) having no aromatic ring include glycidyl ethers of aliphatic alcohols and glycidyl esters of alkylcarboxylic acids, and specific examples thereof include allyl glycidyl ether, butyl glycidyl ether, and sec-butyl. It contains phenylglycidyl ether, 2-ethylhexyl glycidyl ether, alkyl glycidyl ether mixed with 12 and 13 carbon atoms, glycidyl ether of alcohol, monoglycidyl ether of aliphatic higher alcohol, glycidyl ester of higher fatty acid and the like. As the monofunctional epoxy compound (A3), one type of monofunctional epoxy compound may be used alone, or a plurality of different types may be used in combination.

Commercially available products can be used as the monofunctional epoxy compound (A3), for example, "EX-142", "EX-146", EX-147 "," EX-121 "(all of which are Nagase ChemteX Corporation). ), Etc.

(Polyfunctional aromatic epoxy compound (A4))
The polyfunctional aromatic epoxy compound (A4) is a compound having two or more epoxy groups and having an aromatic ring. However, the polyfunctional aromatic epoxy compound (A4) referred to in the present specification excludes compounds having an alicyclic epoxy group in the molecule contained in the alicyclic epoxy compound (A1).

Specific examples of the polyfunctional aromatic epoxy compound (A4) are naphthalene or a polyglycidyl etherified product of a naphthalene derivative (also referred to as “naphthalene type epoxy compound”); a polyglycidyl etherified product of a bisphenol derivative such as bisphenol A or bisphenol F. (Also referred to as "bisphenol A type epoxy compound" and "bisphenol F type epoxy compound"); Epoxy novolak resin; Polyglycidyl etherified product of an aromatic compound having two or more phenolic hydroxyl groups such as resorcinol, hydroquinone, and catechol; Polyglycidyl etherified product of an aromatic compound having two or more alcoholic hydroxyl groups such as benzenedimethanol, benzenediethanol, and benzenedibutanol; a polybase having two or more carboxyl groups such as phthalic acid, terephthalic acid, and trimellitic acid. Polyglycidyl esters of acid aromatic compounds; glycidyl esters of benzoic acid, toluic acid, polyglycidyl esters of naphthoic acid, etc .; styrene oxides such as styrene oxides, alkylated styrene oxides, epoxidates of vinylnaphthalene, or diepoxidates of divinylbenzene. And so on. As the polyfunctional aromatic epoxy compound (A4), one kind of compound may be used alone, or a plurality of different kinds may be used in combination.

Commercially available products can be used as the polyfunctional aromatic epoxy compound (A4). For example, "Denacol EX-201", "Denacol EX-711" and "Denacol EX-721" (all of which are Nagase ChemteX). Co., Ltd.); "Ogsol EG-280" and "Ogsol CG-400" (both manufactured by Osaka Gas Chemical Corporation); "EXA-80CRP" and "HP4032D" (both manufactured by DIC Co., Ltd.) ); "JER828" and "jER828EL" (all manufactured by Mitsubishi Chemical Corporation); "Adeka Resin EP-4100", "Adeka Resin EP-4100G", "Adeka Resin EP-4100E", "Adeka Resin EP-4100L" , "Adeka Resin EP-4100TX", "Adeka Resin EP-4000", "Adeka Resin EP-4005", "Adeka Resin EP-4901", "Adeka Resin EP-4901E", etc. Can be mentioned.

(Oxetane compound (A5))
In the present specification, the oxetane compound (A5) is a compound having an oxetanyl group, and may be an aliphatic compound, an alicyclic compound or an aromatic compound. The oxetane compound (A5) referred to in the present specification is a compound having no epoxy group. With the oxetane compound (A5), the curing rate and viscosity of the active energy ray-curable adhesive composition can be adjusted, and the reactivity can be improved.

The oxetane compound (A5) may be a monofunctional oxetane compound having one oxetaneyl group, or a polyfunctional oxetane compound (A5-1) having two or more oxetaneyl groups. The oxetane compound (A5) is preferably a polyfunctional oxetane compound (A5-1), and more preferably a bifunctional oxetane compound.

Specific examples of the oxetane compound (A5) include 3,7-bis (3-oxetanyl) -5-oxa-nonane and 1,4-bis [(3-ethyl-3-oxetanylmethoxy) methyl] benzene, 1, 2-Bis [(3-ethyl-3-oxetanylmethoxy) methyl] ethane, 1,3-bis [(3-ethyl-3-oxetanylmethoxy) methyl] propane, ethylene glycol bis (3-ethyl-3-oxetanylmethyl) ) Ether, triethylene glycol bis (3-ethyl-3-oxetanylmethyl) ether, tetraethylene glycol bis (3-ethyl-3-oxetanylmethyl) ether ,, 4-bis (3-ethyl-3-oxetanylmethoxy) butane , 1,6-bis (3-ethyl-3-oxetanylmethoxy) hexane, 3-ethyl-3- (phenoxy) methyloxetane, 3-ethyl-3- (cyclohexyloxymethyl) oxetane, 3-ethyl-3-( 2-Ethylhexyloxymethyl) oxetane, 3-ethyl-3-hydroxymethyloxetane, 3-ethyl-3- (chloromethyl) oxetane, 3-ethyl-3 {[(3-ethyloxetane-3-yl) methoxy] methyl} Includes oxetane, xylylene bis oxetane, etc. As the oxetane compound (A5), one kind of oxetane compound may be used alone, or a plurality of different kinds may be used in combination.

Commercially available products can be used as the oxetane compound (A5). For example, the "Aron Oxetane (registered trademark)" series sold by Toa Synthetic Co., Ltd. and Ube Industries, Ltd., respectively, are sold under their trade names. "ETERNACOLL (registered trademark)" series and the like.

The curable components [alicyclic epoxy compound (A1), polyfunctional aliphatic epoxy compound (A2), monofunctional epoxy compound (A3), polyfunctional aromatic epoxy compound (A4), oxetane compound (A5)] are In order to make the active energy ray-curable adhesive composition solvent-free, it is preferable to use one that has not been diluted with an organic solvent or the like.

The above-mentioned curable component is usually liquid at room temperature, has appropriate fluidity even in the absence of a solvent, and is selected to give appropriate adhesive strength, and a suitable photocationic polymerization initiator is blended. In the production equipment of the optical laminate, the activated energy ray-curable adhesive composition can omit the drying equipment for evaporating the solvent in the step of adhering the linear polarizing plate and the retardation layer laminate. Further, by irradiating an appropriate active energy dose, the curing rate can be accelerated and the production rate can be improved.

(Other curable ingredients)
The curable component (A) contained in the active energy ray-curable adhesive composition is not limited to the above-mentioned curable component, and is a cationically polymerizable curable component other than the above-mentioned cationically polymerizable curable component. It may contain a component and a radically polymerizable curable component.

(Radical polymerizable curable component)
A radically polymerizable compound is a compound or oligomer in which a radical polymerization reaction proceeds and is cured by irradiation or heating with active energy rays such as ultraviolet rays, visible light, electron beams, and X-rays, and specifically, an ethylenically unsaturated bond. Can be mentioned. Compounds having an ethylenically unsaturated bond include (meth) acrylic compounds having one or more (meth) acryloyl groups in the molecule, styrene, styrene sulfonic acid, vinyl acetate, vinyl propionate, and N-vinyl. Examples thereof include vinyl compounds such as -2-pyrrolidone. Among them, the preferred radically polymerizable compound is a (meth) acrylic compound.

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. Examples thereof include (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. As the (meth) acrylic compound, only one kind may be used alone, or two or more kinds may be used in combination.

The (meth) acrylate monomer includes a monofunctional (meth) acrylate monomer having one (meth) acryloyloxy group in the molecule and a bifunctional (meth) acrylate having two (meth) acryloyloxy groups in the molecule. Monomers and polyfunctional (meth) acrylate monomers having three or more (meth) acryloyloxy groups in the molecule can be mentioned.

An example of a monofunctional (meth) acrylate monomer is an alkyl (meth) acrylate. In an 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, and the like. Examples thereof include 2-ethylhexyl (meth) acrylate. Also, aralkyl (meth) acrylates such as benzyl (meth) acrylates; (meth) acrylates of terpen alcohols such as isobornyl (meth) acrylates; and tetrahydrofurfuryl structures such as tetrahydrofurfuryl (meth) acrylates (meth). ) Acrylate; has a cycloalkyl group at the alkyl group moiety such as cyclohexyl (meth) acrylate, cyclohexylmethyl methacrylate, dicyclopentanyl acrylate, dicyclopentenyl (meth) acrylate, 1,4-cyclohexanedimethanol monoacrylate (meth). ) Acrylate; Aminoalkyl (meth) acrylate such as N, N-dimethylaminoethyl (meth) acrylate; 2-phenoxyethyl (meth) acrylate, dicyclopentenyloxyethyl (meth) acrylate, ethyl carbitol (meth) acrylate , (Meta) acrylate having an ether bond at the alkyl moiety such as phenoxypolyethylene glycol (meth) acrylate can also be used as the monofunctional (meth) acrylate monomer.

Further, a monofunctional (meth) acrylate having a hydroxyl group at the alkyl moiety and a monofunctional (meth) acrylate having a carboxyl group at the alkyl moiety can also be used. Specific examples of the monofunctional (meth) acrylate having a hydroxyl group at the alkyl moiety include 2-hydroxyethyl (meth) acrylate, 2- or 3-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, and 2-hydroxy. -3-Phenoxypropyl (meth) acrylate, trimethylolpropane mono (meth) acrylate, pentaerythritol mono (meth) acrylate. Specific examples of the monofunctional (meth) acrylate having a carboxyl group at the alkyl moiety include 2-carboxyethyl (meth) acrylate, ω-carboxy-polycaprolactone (n≈2) mono (meth) acrylate, 1- [2- ( Meta) 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 (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 (meth) acrylamide. It may form a ring with the ring, and the ring may have an oxygen atom as a ring member in addition to the carbon atom and the nitrogen atom of (meth) acrylamide. Further, a substituent such as alkyl or oxo (= O) may be bonded to the carbon atom constituting the ring.

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

Examples of the bifunctional (meth) acrylate monomer include alkylene glycol di (meth) acrylate, polyoxyalkylene glycol di (meth) acrylate, halogen-substituted alkylene glycol di (meth) acrylate, aliphatic polyol di (meth) acrylate, and hydrogenation. Di (meth) acrylate of dicyclopentadiene or tricyclodecanediakanol, di (meth) acrylate of dioxane glycol or dioxandialkanol, di (meth) acrylate of alkylene oxide adduct of bisphenol A or bisphenol F, bisphenol A or bisphenol Examples thereof include the epoxy di (meth) acrylate of F.

To give a more specific example of the bifunctional (meth) acrylate monomer, 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, trimethylpropandi (meth) acrylate, pentaerythritol di (meth) acrylate, ditri Methylolpropandi (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, hydroxypivalate neopentyl glycol ester di (meth) acrylate, 2,2-bis [4- (meth) Acryloyloxyethoxyethoxyphenyl] propane, 2,2-bis [4- (meth) acryloyloxyethoxyethoxycyclohexyl] propane, hydrogenated dicyclopentadienyldi (meth) acrylate, tricyclodecanedimethanol di (meth) acrylate , 1,3-Dioxane-2,5-diyldi (meth) acrylate [also known as dioxane glycol di (meth) acrylate], acetal compound of hydroxypivalaldehyde and trimethylpropane [chemical name: 2- (2-hydroxy) -1,1-Dimethylethyl) -5-ethyl-5-hydroxymethyl-1,3-dioxane] di (meth) acrylate, tris (hydroxyethyl) isocyanurate di (meth) acrylate and the like.

Examples of the trifunctional or higher functional polyfunctional (meth) acrylate monomer include glycerin tri (meth) acrylate, alkoxylated glycerin tri (meth) acrylate, trimethylolpropane tri (meth) acrylate, trimethylolpropane tri (meth) acrylate, and ditrimethylol. Propanetetra (meth) acrylate, pentaerythritol trimethylolpropane (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, etc. Poly (meth) acrylates of trifunctional or higher functional aliphatic polyols are typical, and in addition, poly (meth) acrylates of trifunctional or higher functional halogen-substituted polyols and glycerin alkylene oxide adduct tri (meth) Acrylate, tri (meth) acrylate of alkylene oxide adduct of trimethylolpropane, 1,1,1-tris [(meth) acryloyloxyethoxyethoxy] propane, tris (hydroxyethyl) isocyanurate tri (meth) acrylate 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.

The 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 polyisocyanate, or a polyol as polyisocyanate. It can be a urethanization reaction product of a terminal isocyanato group-containing urethane compound obtained by reaction and 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 and 2-hydroxypropyl (meth). ) Acrylate, 2-Hydroxybutyl (meth) acrylate, 2-hydroxy-3-phenoxypropyl (meth) acrylate, glycerindi (meth) acrylate, trimethylpropandi (meth) acrylate, pentaerythritol tri (meth) acrylate, di Contains pentaerythritol penta (meth) acrylate. Specific examples other than the hydroxyl group-containing (meth) acrylate monomer include N-hydroxyalkyl (meth) acrylamide monomers such as N-hydroxyethyl (meth) acrylamide and N-methylol (meth) acrylamide.

Examples of the polyisocyanate used for the urethanization reaction with the hydroxyl group-containing (meth) acrylic monomer include hexamethylene diisocyanate, lysine diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, tolylene diisocyanate, xylylene diisocyanate, and among these diisocyanates, aromatic ones. Diisocyanates obtained by hydrogenating isocyanates (for example, hydrogenated tolylene diisocyanates, hydrogenated xylylene diisocyanates, etc.), di- or tri-isocyanates such as triphenylmethane triisocyanates, dibenzylbenzene triisocyanates, and the above. Examples thereof include polyisocyanate obtained by increasing the amount of diisocyanate.

Further, as the polyol used to obtain a terminal isocyanato group-containing urethane compound by reaction with polyisocyanate, a polyester polyol, a polyether polyol, or the like can be used in addition to an aromatic, aliphatic or alicyclic polyol. it can. Examples of aliphatic and alicyclic polyols include 1,4-butanediol, 1,6-hexanediol, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, neopentyl glycol, trimethylolethane, trimethylolpropane, and ditri. Examples thereof include methylolpropane, pentaerythritol, dipentaerythritol, dimethylolheptan, dimethylolpropionic acid, dimethylolbutanoic acid, glycerin, hydrogenated bisphenol A and the like.

The polyester polyol is obtained by a dehydration condensation reaction between the above-mentioned polyol and a polybasic carboxylic acid or an anhydride thereof. Examples of polybasic carboxylic acids or their anhydrides, which may be anhydrides, are represented by adding "(anhydride)" to (anhydrous) succinic acid, adipic acid, (anhydrous) maleic acid, (anhydrous). There are 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, a polybasic carboxylic acid or an anhydride thereof, and a polyol. Examples of polybasic carboxylic acids or their anhydrides used in the dehydration condensation reaction, which can be anhydrous, are represented by adding "(anhydride)" to (anhydrous) succinic acid, adipic acid, (anhydride). There are maleic acid, (anhydrous) itaconic acid, (anhydrous) trimellitic acid, (anhydrous) pyromellitic acid, hexahydro (anhydride) phthalic acid, (anhydrous) phthalic acid, isophthalic acid, terephthalic acid and the like. Examples of the polyol used in the dehydration condensation reaction include 1,4-butanediol, 1,6-hexanediol, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, neopentyl glycol, trimethylolethane, and trimethylolpropane. Examples thereof include ditrimethylolpropane, pentaerythritol, dipentaerythritol, dimethylolheptan, dimethylolpropionic acid, dimethylolbutanoic acid, glycerin, and hydrogenated bisphenol A.

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

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

The blending amount of the photoradical polymerization initiator is usually 0.5 parts by mass or more and 20 parts by mass or less, preferably 1 part by mass or more and 6 parts by mass or less with respect to 100 parts by mass of the radically polymerizable compound. By blending 0.5 parts by mass or more of the photoradical polymerization initiator, the radically polymerizable compound can be sufficiently cured, and high mechanical strength and adhesive strength can be imparted to the obtained polarizing plate. On the other hand, if the amount is excessively large, the durability of the polarizing plate may decrease.

However, since radical polymerization tends to have a large curing shrinkage, it is preferable that the active energy ray-curable adhesive composition contains only a cationically polymerizable curable component as the curable component (A).

(Photocationic polymerization initiator (B))
The active energy ray-curable adhesive composition contains a photocationic polymerization initiator (B). As a result, the curable component (A) can be cured by cationic polymerization by irradiation with active energy rays to form an adhesive layer. The photocationic polymerization initiator (B) generates a cationic species or Lewis acid by irradiation with active energy rays such as visible light, ultraviolet rays, X-rays, and electron beams, and initiates the polymerization reaction of the curable component (A). It is something that makes you. Since the photocationic polymerization initiator (B) acts catalytically with light, it is excellent in storage stability and workability even when mixed with the curable component (A). As a compound that can be used as a photocationic polymerization initiator (B) and produces a cationic species or Lewis acid by irradiation with active energy rays, for example, an aromatic diazonium salt; an onium salt such as an aromatic iodonium salt or an aromatic sulfonium salt. ; Iron-alene complex and the like can be mentioned.

Examples of the aromatic diazonium salt include benzenediazonium hexafluoroantimonate, benzenediazonium hexafluorophosphate, and benzenediazonium hexafluoroborate.

Examples of the aromatic iodonium salt include diphenyl iodonium tetrakis (pentafluorophenyl) borate, diphenyl iodonium hexafluorophosphate, diphenyl iodonium hexafluoroantimonate, and di (4-nonylphenyl) iodonium hexafluorophosphate.

Examples of the aromatic sulfonium salt include triphenylsulfonium hexafluorophosphate, triphenylsulfonium hexafluoroantimonate, triphenylsulfonium tetrakis (pentafluorophenyl) borate, and 4,4'-bis [diphenylsulfonio] diphenylsulfide bishexa. Fluorophosphate, 4,4'-bis [di (β-hydroxyethoxy) phenylsulfonio] diphenylsulfide bishexafluoroantimonate, 4,4'-bis [di (β-hydroxyethoxy) phenylsulfonio] diphenylsulfide bis Hexafluorophosphate, 7- [di (p-toluyl) sulfonio] -2-isopropylthioxanthone hexafluoroantimonate, 7- [di (p-toluyl) sulfonio] -2-isopropylthioxanthone tetrakis (pentafluorophenyl) borate, 4 -Phenylcarbonyl-4'-diphenylsulfonio-diphenylsulfide hexafluorophosphate, 4- (p-tert-butylphenylcarbonyl) -4'-diphenylsulfonio-diphenylsulfide hexafluoroantimonate, 4- (p-tert- Butylphenylcarbonyl) -4'-di (p-toluyl) sulfonio-diphenylsulfide tetrakis (pentafluorophenyl) borate.

Examples of the iron-arene complex include xylene-cyclopentadienyl iron (II) hexafluoroantimonate, cumene-cyclopentadienyl iron (II) hexafluorophosphate, and xylene-cyclopentadienyl iron (II) tris ( Trifluoromethylsulfonyl) metanide.

As the photocationic polymerization initiator (B), only one type may be used alone, or two or more types may be used in combination. Among the above, the aromatic sulfonium salt is particularly preferable because it has ultraviolet absorption characteristics even in the wavelength region near 300 nm, and thus it is possible to obtain an adhesive cured layer having excellent curability and good mechanical strength and adhesive strength. Used.

The content of the photocationic polymerization initiator (B) is 0.5 parts by mass or more and 10 parts by mass or less, preferably 1 part by mass or more and 4 parts by mass with respect to 100 parts by mass of the total amount of the curable component (A). It is as follows. By containing 1 part by mass or more of the photocationic polymerization initiator (B), the curable component can be sufficiently cured, and an adhesive cured layer having sufficient adhesive strength and hardness can be obtained. On the other hand, if the amount is large, the amount of ionic substances in the cured product increases, which increases the hygroscopicity of the cured product and may reduce the durability performance of the laminate. Therefore, the photocationic polymerization initiator (B) ) Is 10 parts by mass or less with respect to 100 parts by mass of the total amount of the curable component (A).

When a radically polymerizable curable component is contained as the curable component, it is preferable to include a radical polymerization initiator in addition to the photocationic polymerization initiator (B) as the polymerization initiator.

(Photosensitizer (C))
The active energy ray-curable adhesive composition may contain a photosensitizer (C). By including the photosensitizer (C) in the first active energy ray-curable composition, the curability of the adhesive can be improved as compared with the case where it is not contained.

The photosensitizer (C) is based on the following general formula (I):

(In the formula, R ¹ and R ² represent an alkyl group having 1 to 6 carbon atoms or an alkoxyalkyl group having 2 to 12 carbon atoms independently of each other, and R ³ represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms. )
Includes anthracene compounds represented by. The photocationic polymerization initiator (B) exhibits maximum absorption in a wavelength region near 300 nm or shorter, generates cation species or Lewis acid in response to light having a wavelength in the vicinity, and is cationically polymerizable. The photosensitizer (C) preferably exhibits maximum absorption in a wavelength region longer than 380 nm so as to initiate cationic polymerization of the sex component and to be sensitive to light having a wavelength longer than that. As such a photosensitizer (C), an anthracene-based compound is preferably used.

Specific examples of anthracene compounds include, for example.
9,10-dimethoxyanthracene,
9,10-diethoxyanthracene,
9,10-Dipropoxyanthracene,
9,10-diisopropoxyanthracene,
9,10-Dibutoxyanthracene,
9,10-Dipentyloxyanthracene,
9,10-dihexyloxyanthracene,
9,10-bis (2-methoxyethoxy) anthracene,
9,10-bis (2-ethoxyethoxy) anthracene,
9,10-Bis (2-butoxyethoxy) anthracene,
9,10-Bis (3-butoxypropoxy) anthracene,
2-Methyl or 2-ethyl-9,10-dimethoxyanthracene,
2-Methyl or 2-Ethyl-9,10-diethoxyanthracene,
2-Methyl or 2-Ethyl-9,10-dipropoxyanthracene,
2-Methyl or 2-ethyl-9,10-diisopropoxyanthracene,
2-Methyl or 2-Ethyl-9,10-dibutoxyanthracene,
2-Methyl or 2-ethyl-9,10-dipentyloxyanthracene,
Examples thereof include 2-methyl or 2-ethyl-9,10-dihexyloxyanthracene.

By including the photosensitizer (C) in the active energy ray-curable adhesive composition, the curability of the adhesive can be improved as compared with the case where it is not contained. Such an effect can be exhibited by setting the content of the photosensitizer to 0.1 parts by mass or more with respect to 100 parts by mass of the total amount of the curable component (A). On the other hand, if the content of the photosensitizer (C) is large, problems such as precipitation during low temperature storage occur. Therefore, the content is 2 with respect to 100 parts by mass of the total amount of the curable component (A). It is preferably less than or equal to parts by mass.

(Photosensitizer (D))
The active energy ray-curable adhesive composition may contain a photosensitizer (D). The photosensitizer (D) is preferably a naphthalene-based photosensitizer.

Specific examples of naphthalene-based photosensitizers include, for example.
4-Methoxy-1-naphthol,
4-ethoxy-1-naphthol,
4-propoxy-1-naphthol,
4-Butoxy-1-naphthol, 4-hexyloxy-1-naphthol,
1,4-dimethoxynaphthalene,
1-ethoxy-4-methoxynaphthalene,
1,4-Diethoxynaphthalene,
1,4-Dipropoxynaphthalene,
Examples include 1,4-dibutoxynaphthalene.

By including a naphthalene-based photosensitizer in the active energy ray-curable adhesive composition, the curability of the adhesive can be improved as compared with the case where it is not contained. Such an effect can be exhibited by setting the content of the naphthalene-based photosensitizer to 0.1 parts by mass or more with respect to 100 parts by mass of the total amount of the curable component (A). On the other hand, if the content of the naphthalene-based photosensitizer increases, problems such as precipitation during low-temperature storage occur. Therefore, the content is 5 with respect to 100 parts by mass of the total amount of the curable component (A). It is preferably less than or equal to parts by mass. The content of the naphthalene-based photosensitizer is preferably 3 parts by mass or less with respect to 100 parts by mass of the total amount of the curable component (A).

(Additive component (E))
The active energy ray-curable adhesive composition may contain an additive component (E) as another component which is an optional component as long as the effects of the present invention are not impaired. The additive component (E) includes an ion trap agent, an antioxidant, a light stabilizer, a chain transfer agent, a tackifier, a thermoplastic resin, a filler, a flow conditioner, a plasticizer, a defoaming agent, and a leveling agent. Examples include dyes and organic solvents.

When the additive component (E) is contained, the content thereof is preferably 10 parts by mass or less with respect to 100 parts by mass of the total amount of the curable component (A).

The above-mentioned photocationic polymerization initiator (B), photosensitizer (C), photosensitizer (D), and additive component (E) were used when preparing the active energy ray-curable adhesive composition. It may be added without a solvent, or it may be diluted with a solvent and then added directly. The above-mentioned numerical range of the content is a numerical range based on the solid content.

As a uniform form of the present invention, the active energy ray-curable composition forming the first cured product layer contains an epoxy compound (A2-1) containing a three-ring condensed ring and two glycidyl ether groups in the molecule. The composition is preferably contained.
When the active energy ray-curable composition contains an epoxy compound (A2-1) containing a three-ring condensed ring and two glycidyl ether groups in the molecule, it is preferable to further contain an oxetane compound (A5). , A polyfunctional oxetane compound (A5-1) is more preferable, and a bifunctional oxetane compound is further preferably contained.
When the active energy ray-curable composition contains an epoxy compound (A2-1) and an oxetane compound (A5) containing a three-ring condensed ring and two glycidyl ether groups in the molecule, it is further alicyclic. At least one selected from the epoxy compound (A1) and the polyfunctional aliphatic epoxy compound (A2) (excluding the epoxy compound (A2-1) containing a tricyclic condensed ring and two glycidyl ether groups in the molecule). It is preferable to include one type.

When the active energy ray-curable composition contains an epoxy compound (A2-1) and an oxetane compound (A5) containing a three-ring condensed ring and two glycidyl ether groups in the molecule, the oxetane compound (A5) The content of is higher than the content of the epoxy compound (A2-1) containing a three-ring condensed ring and two glycidyl ether groups in the molecule. When the active energy ray-curable composition contains an epoxy compound (A2-1) containing a three-ring condensed ring and two glycidyl ether groups in the molecule, and a polyfunctional oxetane compound (A5-1), there are many cases. The content of the functional oxetane compound (A5-1) is preferably higher than the content of the epoxy compound (A2-1) containing a tricyclic condensed ring and two glycidyl ether groups in the molecule. The content ratio (mass ratio) of the polyfunctional oxetane compound (A5-1), the tricyclic condensed ring, and the epoxy compound (A2-1) containing two glycidyl ether groups in the molecule is the polyfunctional oxetane compound (mass ratio). The epoxy compound (A2-1) containing the condensed ring of A5-1) / 3 ring type and two glycidyl ether groups in the molecule is preferably 1.1 / 1 to 5/1, and 1.5 / It is more preferably 1 to 5/1, and even more preferably 2/1 to 5/1. Within the above range, a cured film having a high crosslink density can be easily obtained, so that the amount of iodine transfer can be suppressed.
When the active energy ray-curable composition contains an epoxy compound (A2-1) and an oxetane compound (A5) containing a three-ring fused ring and two glycidyl ether groups in the molecule, the oxetane compound (A5) The content of is preferably 35% by mass or more, preferably 80% by mass or less, more preferably 75% by mass or less, and 70% by mass based on the total mass of the curable component (A). It is more preferably less than or equal to%.
When the active energy ray-curable composition contains an epoxy compound (A2-1) containing a tricyclic condensed ring and two glycidyl ether groups in the molecule and an oxetane compound (A5), the tricyclic condensation The content of the epoxy compound (A2-1) containing a ring and two glycidyl ether groups in the molecule is preferably 1% by mass or more based on the total mass of the curable component (A), and is preferably 5% by mass. More preferably, it is less than 35% by mass, and more preferably 30% by mass or less.

(viscosity)
The viscosity of the active energy ray-curable adhesive composition may be any one having a viscosity that can be applied by various methods, but the viscosity at a temperature of 25 ° C. may be, for example, 200 mPa · s or less, which is preferable. Is 0.1 mPa · s or more and 180 mPa · s or less. If the viscosity is too small, 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 be difficult to flow, and it tends to be difficult to obtain a uniform and uniform coating film. The viscosity referred to here is a value measured at 10 rpm after adjusting the temperature of the adhesive to 25 ° C. using an E-type viscometer.

(Curing method)
The active energy ray-curable adhesive composition can be used in the form of an electron beam-curable type or an ultraviolet-curable type. As used herein, an active energy ray is defined as an energy ray capable of decomposing a compound that generates an active species to generate an active species. Examples of such active energy rays include visible light, ultraviolet rays, infrared rays, X-rays, α-rays, β-rays, γ-rays and electron beams.

In the electron beam curing type, any appropriate conditions can be adopted as the electron beam irradiation conditions as long as the active energy ray curing adhesive composition can be cured. For example, in electron beam irradiation, the acceleration voltage is preferably 5 kV or more and 300 kV or less, and more preferably 10 kV or more and 250 kV or less. 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 penetrating force through the sample is too strong and the electron beam bounces off, and a transparent protective film or There is a risk of damaging the polarizer. The irradiation dose is 5 kGy or more and 100 kGy or less, more preferably 10 kGy or more and 75 kGy or less. When the irradiation dose is less than 5 kGy, the adhesive is insufficiently cured, and when it exceeds 100 kGy, the optical layer is damaged, mechanical strength is lowered and yellowing occurs, and desired optical characteristics cannot be obtained.

Electron beam irradiation is usually performed in an inert gas, but if necessary, it may be performed in the atmosphere or under conditions where a small amount of oxygen is introduced. By appropriately introducing oxygen, it is possible to prevent damage to other optical layers by intentionally causing oxygen inhibition in the optical layer to which the electron beam first hits, and to efficiently irradiate only the adhesive with the electron beam. Can be done.

In the ultraviolet curable type, the light irradiation intensity of the active energy ray-curable adhesive composition is determined for each adhesive composition and is not particularly limited, but is 10 mW / cm ² or more and 1,000 mW / cm ² or less. Is preferable. If the light irradiation intensity of 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} , the heat radiated from the light source and the heat generated during the polymerization of the composition cause. , May cause yellowing of the constituent materials of the adhesive. The irradiation intensity is preferably an intensity in a wavelength region effective for activating the photocationic polymerization initiator (B), more preferably an intensity in a wavelength region having a wavelength of 400 nm or less, and further preferably a wavelength of 280 nm or more and 320 nm. The intensity in the following wavelength region. Such once with light intensity or by irradiation a plurality of times, the integrated light quantity is preferably 10 mJ / cm ² or more, more preferably set to be 100 mJ / cm ² or more 1,000 mJ / cm ² or less .. If the integrated light intensity to the adhesive is ^{less than 10 mJ / cm 2} , the active species derived from the polymerization initiator are not sufficiently generated, and the adhesive is not sufficiently cured. On the other hand, if the integrated light intensity ^{exceeds 1,000 mJ / cm 2} , the irradiation time becomes long, which is disadvantageous for improving productivity. At this time, depending on the type of the first retardation layer 30 and the second retardation layer 40, the combination of the adhesive types, etc., the wavelength region (UVA (320 nm or more and 390 nm or less), UVB (280 nm or more and 320 nm or less), etc.) and its integration. The amount of light can be set as appropriate.

The light source used for polymerizing and curing the active energy ray-curable adhesive composition by irradiation with the active energy ray in the present invention is not particularly limited, but for example, a low-pressure mercury lamp, a medium-pressure mercury lamp, a high-pressure mercury lamp, and an ultra-high-pressure mercury lamp. Examples thereof include xenon lamps, halogen lamps, carbon arc lamps, tungsten lamps, gallium lamps, excima lasers, LED light sources that emit light in a wavelength range of 380 nm or more and 440 nm or less, chemical lamps, black light lamps, microwave-excited mercury lamps, and metal halide lamps. From the viewpoint of energy stability and simplicity of the apparatus, an ultraviolet light source having an emission distribution having a wavelength of 400 nm or less is preferable.

(Storage modulus of the first cured product layer)
_{The storage elastic modulus (E 1} ) of the first cured product layer at a temperature of 80 ° C. is preferably 300 MPa or more, more preferably 500 MPa or more, and more preferably 1000 MPa or more from the viewpoint of suppressing corrosion of the conductive layer. Is even more preferable. Further, it is preferably 5000 MPa or less, more preferably 4000 MPa or less, and further preferably 3500 MPa or less. The storage elastic modulus (E ₁ ) of the first cured product layer is measured by the method described in the section of Examples described later.

The storage elastic modulus (E ₁ ) of the first cured product layer at a temperature of 80 ° C. and the storage elastic modulus (E ₂ ) of the second cured product layer at a temperature of 80 ° C., which will be described later, suppress corrosion and cause cracks during the durability test. From the viewpoint of suppression, it is preferable to satisfy the relationship of _{E 1} > E _{2 , and when E 1} −E ₂ = ΔE, ΔE is more preferably 2000 MPa or less, and further preferably 1500 MPa or less.

It is preferable that the difference between the storage elastic modulus at a temperature of 30 ° C. and the storage elastic modulus at a temperature of 80 ° C. of the first cured product layer is not too large. If the difference between the storage elastic modulus at a temperature of 30 ° C. and the storage elastic modulus at a temperature of 80 ° C. is too large, metal corrosion tends to occur easily. The difference between the storage elastic modulus at a temperature of 30 ° C. and the storage elastic modulus at a temperature of 80 ° C. is preferably 1500 MPa or less.

(Glass transition temperature of the first cured product layer)
The glass transition temperature (Tg ₁ ) of the first cured product layer is preferably 65 ° C. or higher, more preferably 70 ° C. or higher, and 75 ° C. or higher from the viewpoint of suppressing corrosion of the conductive layer. Is even more preferable. Further, it is preferably 200 ° C. or lower, more preferably 150 ° C. or lower, and even more preferably 120 ° C. or lower. The glass transition temperature (Tg ₁ ) of the first cured product layer is measured by the method described in the section of Examples described later.

(Humidity permeability of the first cured product layer)
The moisture permeability of the first cured product layer at a temperature of 80 ° C. is preferably low from the viewpoint of suppressing metal corrosion. First cured layer having a thickness of 30μm is by cup method defined in JIS Z 0208, temperature 80 ° C., the moisture permeability being measured under the conditions of a relative humidity of 90%, preferably from 1500g ^/ (m 2 · 24hr) or less , more preferably 1000g ^/ (m 2 · 24hr) or less, still more preferably 950g ^/ (m 2 · 24hr) or less. The transparent humidity is usually 100g ^/ (m 2 · 24hr) or more.

Specifically, the moisture permeability J of the first cured film is a laminate (for example, 20 μm triacetyl cellulose film / 5 μm pressure-sensitive adhesive layer /) in which the first cured product layer is formed on a base film or the like having a known moisture permeability. A laminated body of the first cured product layer having a thickness of 30 μm) is produced, the moisture permeability of the laminated body is measured by the above method, and the measurement result can be used to obtain it based on the following formula.
1 / Jt = (1 / J) + (1 / Jsub)
In the above formula, Jt is the moisture permeability of the laminated body, and Jsub is the moisture permeability in the layer structure obtained by removing the first cured product layer from the laminated body. When measuring the moisture permeability of the laminate according to JIS Z 0208, the laminate is attached to the cup with the cured film facing outward.
For example, a laminate having a layer structure of 20 μm triacetyl cellulose film / 5 μm pressure-sensitive adhesive layer / 30 μm-thick first cured product layer has a temperature of 80 ° C. and a relative humidity of 90 by the cup method specified in JIS Z 0208. moisture permeability, measured in% conditions are preferably at 1000g ^/ (m 2 · 24hr) or less and more preferably 950g ^/ (m 2 · 24hr) or less. The transparent humidity is usually 100g ^/ (m 2 · 24hr) or more.

(Phase difference layer)
The optical laminate of the present invention includes a retardation layer 20 having at least one retardation layer which is a polymer of a polymerizable liquid crystal compound. The retardation layer 20 is not particularly limited as long as it is a retardation layer including at least one retardation expression layer that gives a predetermined retardation to light, and is, for example, a 1/2 wavelength layer, a 1/4 wavelength layer, and a positive C plate. It may be an optical compensation layer such as. The retardation layer may be a positive dispersion retardation layer or a reverse wavelength dispersion retardation layer. The retardation layer 20 may be composed of only the retardation expression layer as long as it contains at least one retardation expression layer, or may include another layer together with the retardation expression layer. May be good. Examples of other layers include a base material layer, an alignment film layer, a protective layer and the like. The other layers do not affect the value of the phase difference. Further, the retardation layer 20 may be composed of two layers, a first retardation layer 30 and a second retardation layer 40. Hereinafter, the laminated body in which the first retardation layer 30 and the second retardation layer 40 are adhered to each other via the second cured product layer 50 described later is also referred to as a retardation layer laminate 60.

Examples of the retardation expression layer include a layer containing a polymer of a polymerizable liquid crystal compound (hereinafter, also referred to as a liquid crystal layer) or a stretched film. At least one of the first retardation layer 30 and the second retardation layer 40 is preferably a liquid crystal layer. When the first retardation layer 30 is a liquid crystal layer, it is preferable that the surface of the first retardation layer 30 on the side of the second cured product layer 50 is a liquid crystal layer which is a retardation expression layer. When the second retardation layer 40 is a liquid crystal layer, it is preferable that the surface of the second retardation layer 40 on the side of the second cured product layer 50 is a liquid crystal layer which is a retardation expression layer. The retardation expression layer, which is a liquid crystal layer, is generally easier to thin than the retardation expression layer, which is a stretched film.

At least one of the first retardation layer 30 and the second retardation layer 40 has a light transmittance of preferably 5% or more, more preferably 10% or more, still more preferably, from the viewpoint of adhesion at a wavelength of 320 nm. Is more than 30%. The light transmittance can be measured according to the measurement method described in the column of Examples described later.

At least one of the first retardation layer 30 and the second retardation layer 40 preferably has a light transmittance of 0% or more and 10% or less at a wavelength of 380 nm and a light transmittance of 30% or more at a wavelength of 400 nm. Yes, more preferably, the light transmittance at a wavelength of 380 nm is 0% or more and 5% or less, and the light transmittance at a wavelength of 400 nm is 35% or more, and even more preferably, the light transmittance at a wavelength of 380 nm is 0%. It is 1% or less, and the light transmittance at a wavelength of 400 nm is 40% or more.

When the first retardation layer 30 and the second retardation layer 40 are each composed of only a retardation expression layer, the thickness thereof is preferably 0.5 μm or more and 10 μm or less, and 0.5 μm or more and 5 μm or less. Is more preferable.
When the first retardation layer 30 and the second retardation layer 40 include layers other than the retardation expression layer (base material layer, alignment film layer, protective layer, etc.), the total thickness is 0.5 μm or more and 300 μm. It is preferably 0.5 μm or more, and more preferably 150 μm or less.

As a combination of the first retardation layer 30 and the second retardation layer 40, for example,
i) Combination of 1/2 wavelength layer and 1/4 wavelength layer,
ii) Combination of 1/2 wavelength layer and optical compensation layer,
iii) Combination of 1/4 wavelength layer and optical compensation layer,
And so on.

In the case of i), it is preferable that the first retardation layer 30 is a 1/2 wavelength layer and the second retardation layer 40 is a 1/4 wavelength layer.

In the case of ii), it is preferable that the first retardation layer 30 is a 1/2 wavelength layer, the second retardation layer 40 is an optical compensation layer, and the first retardation layer 30 is a 1/2 wavelength layer. , It is more preferable that the second retardation layer 40 is a positive C plate.

In the case of iii), it is preferable that the first retardation layer 30 is a 1/4 wavelength layer, the second retardation layer 40 is an optical compensation layer, and the first retardation layer 30 is a 1/4 wavelength layer. , It is more preferable that the second retardation layer 40 is a positive C plate.

The 1/2 wavelength 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 of changing the direction of linearly polarized light (polarization direction). .. Further, when circularly polarized light is incident, the direction of rotation of circularly polarized light can be reversed.

The 1/2 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 / 2. Re (λ) = λ / 2 may be achieved at any wavelength in the visible light region, but it is particularly preferable that it is achieved at a wavelength of 550 nm. The in-plane retardation value of Re (550) at a wavelength of 550 nm preferably satisfies 210 nm ≦ Re (550) ≦ 300 nm. Further, it is more preferable to satisfy 220 nm ≦ Re (550) ≦ 290 nm.

The 1/4 wavelength layer gives a phase difference of π / 2 (= λ / 4) to the electric field vibration direction (polarization plane) of the incident light, and linearly polarized light of a specific wavelength is changed to circularly polarized light (or circularly polarized light). It has the function of converting polarized light (to 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 region. However, it is preferable that the wavelength is 550 nm. It is preferable that Re (550), which is an in-plane retardation value at a wavelength of 550 nm, satisfies 100 nm ≦ Re (550) ≦ 160 nm. Further, it is more preferable to satisfy 110 nm ≦ Re (550) ≦ 150 nm.

Examples of the optical compensation layer include a positive A plate and a positive C plate. The positive A plate has Nx> Ny when the refractive index in the slow axis direction in the plane is Nx, the refractive index in the phase advance axis direction in the plane is Ny, and the refractive index in the thickness direction is Nz. Satisfy 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.

The inverse wavelength dispersibility is an optical characteristic in which the in-plane retardation value at a short wavelength is smaller than the in-plane retardation value at a long wavelength, and the following equation (2):
Re (450) ≤ Re (550) ≤ Re (650) (2)
To meet. Re (λ) represents an in-plane retardation value for light having a wavelength of λ nm.

The optical characteristics of the retardation layer can be adjusted by the orientation 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 characteristics of the retardation layer, the retardation layer laminate and the linear polarizing plate can be laminated to obtain a polarizing plate composite having antireflection performance.

(Phase difference expression layer formed from the liquid crystal layer)
A case where the retardation expression 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 another layer. The first retardation layer 30 shown in FIG. 2 is formed by laminating a base material layer 31, an alignment layer 32, and a retardation expression layer 33, which is a liquid crystal layer, in this order. The retardation layer is not limited to the first retardation layer 30 shown in FIG. 2 as long as it includes the retardation expression layer 33 of the liquid crystal layer, and the base material layer 31 is separated from the first retardation layer 30. The configuration may be composed of only the alignment layer 32 and the phase difference expression layer 33, and the base material layer 31 and the alignment layer 32 are separated from the first retardation layer 30 and only from the phase difference expression layer 33 of the liquid crystal layer. It may be configured as follows. From the viewpoint of thinning, the retardation layer preferably has a structure in which the base material layer 31 is peeled off, and more preferably a structure consisting of only the retardation expression layer 33 of the liquid crystal layer. The base material layer 31 has a function as a support layer that supports the alignment layer 32 formed on the base material layer 31 and the retardation expression layer 33 of the liquid crystal layer. The base material layer 31 is preferably a film made of a resin material.

As the resin material, for example, a resin material having excellent transparency, mechanical strength, thermal stability, stretchability, etc. is used. Specifically, polyolefin resins such as polyethylene and polypropylene; cyclic polyolefin resins such as norbornene polymers; polyester resins such as polyethylene terephthalate and polyethylene naphthalate; (meth) acrylic acid, poly (meth) methyl acrylate and the like. (Meta) acrylic acid resin; cellulose ester resin such as triacetyl cellulose, diacetyl cellulose and cellulose acetate propionate; vinyl alcohol resin such as polyvinyl alcohol and polyvinyl acetate; polycarbonate resin; polystyrene resin; poly Arilate-based resin; polysulfone-based resin; polyether sulfone-based resin; polyamide-based resin; polyimide-based resin; polyether ketone-based resin; polyphenylene sulfide-based resin; polyphenylene oxide-based resin, and mixtures and copolymers thereof. Can be done. Among these resins, it is preferable to use any one of cyclic polyolefin-based resin, polyester-based resin, cellulose ester-based resin and (meth) acrylic acid-based resin, or a mixture thereof. The above-mentioned "(meth) acrylic acid" means "at least one 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 resins, or may have a multilayer structure of two or more layers. When having a multi-layer structure, the resins forming each layer may be the same or different.

Any additive may be added to the resin material forming the resin film. Examples of the additive include an ultraviolet absorber, an antioxidant, a lubricant, a plasticizer, a mold release agent, an antioxidant, a flame retardant, a nucleating agent, an antistatic agent, a pigment, and a coloring agent.

The thickness of the base material layer 31 is not particularly limited, but is generally preferably 5 μm or more and 200 μm or less, more preferably 10 μm or more and 200 μm or less, and 10 μm or more and 150 μm from the viewpoint of workability such as strength and handleability. The following is more preferable.

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, or the like. A primer layer or the like may be formed. When the base material layer 31, or the base material layer 31 and the alignment layer 32 are peeled off to form a retardation layer, the peeling can be facilitated by adjusting the adhesion at the peeling interface.

The alignment layer 32 has an orientation regulating force that aligns the liquid crystal compound contained in the phase difference expressing layer 33 of the liquid crystal layer formed on the alignment layer 32 in a desired direction. Examples of the oriented layer 32 include an oriented polymer layer formed of an oriented polymer, a photo-aligned polymer layer formed of a photo-aligned polymer, and a grub-aligned layer having a concavo-convex pattern and a plurality of grubs (grooves) on the layer surface. Can be done. The thickness of the alignment layer 32 is usually 0.01 μm or more and 10 μm or less, and preferably 0.01 μm or more and 5 μm or less.

The oriented polymer layer can be formed by applying a composition in which the oriented polymer is dissolved in a solvent to the base material layer 31 to remove the solvent, and if necessary, rubbing treatment. In this case, the orientation regulating force can be arbitrarily adjusted in the orientation polymer layer formed of the orientation polymer depending on the surface condition of the orientation polymer and the rubbing conditions.

The photo-aligned polymer layer can be formed by applying a composition containing a polymer or monomer having a photoreactive group and a solvent to the base material layer 31 and irradiating it with polarized light. In this case, in the photo-alignment polymer layer, the orientation-regulating force can be arbitrarily adjusted depending on the polarization irradiation conditions of the photo-alignment polymer.

The grub alignment layer is active on a plate-shaped master having grooves on the surface, for example, a method of forming a concavo-convex pattern by exposure, development, etc. through an exposure mask having a pattern-shaped slit on the surface of a photosensitive polyimide film. A method of forming an uncured layer of an energy ray-curable resin and transferring this layer to a base material layer 31 for curing. A method of forming an uncured layer of an active energy ray-curable resin on the base material layer 31 and then forming the uncured layer of the active energy ray-curable resin. It can be formed by a method of forming irregularities by pressing a roll-shaped master having irregularities against the layer and hardening the layers.

The phase difference expression layer 33, which is a liquid crystal layer, is not particularly limited as long as it gives a predetermined phase difference to light, and is, for example, a phase difference expression layer for a 1/2 wavelength layer and a position for a 1/4 wavelength layer. Examples thereof include a phase difference expression layer, a phase difference expression layer for an optical compensation layer such as a positive C plate, and a phase difference expression layer for an inverse wavelength dispersibility 1/4 wavelength layer.

The phase difference expression layer 33, which is a liquid crystal layer, can be formed by using a known liquid crystal compound. The type of the liquid crystal compound is not particularly limited, and a rod-shaped liquid crystal compound, a disk-shaped liquid crystal compound, and a mixture 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. Examples of the liquid crystal compound include JP-A-11-513019, JP-A-2005-289980, JP-A-2007-108732, JP-A-2010-2404038, JP-A-2010-31223, and JP-A. The liquid crystal compounds described in JP-A-2010-270108, JP-A-2011-6360, JP-A-2011-207765, JP-A-2016-81035, WO2017 / 043438 and JP-A-2011-207765. Can be mentioned.

For example, when a polymerizable liquid crystal compound is used, a composition containing the polymerizable liquid crystal compound is applied onto the alignment layer 32 to form a coating film, and the coating film is cured to cure the retardation layer 33. Can be formed. The thickness of the retardation expression layer 33 is preferably 0.5 μm or more and 10 μm or less, and more preferably 0.5 μm or more and 5 μm or less.
The composition containing the polymerizable liquid crystal compound may contain a polymerization initiator, a polymerizable monomer, a surfactant, a solvent, an adhesion improver, a plasticizer, an alignment agent and the like in addition to the liquid crystal compound. Examples of the method for applying the composition containing the polymerizable liquid crystal compound include known methods such as a die coating method. Examples of the curing method of the composition containing the polymerizable liquid crystal compound include known methods such as irradiation with active energy rays (for example, ultraviolet rays).

(A retardation layer having a stretched film as a retardation expression layer)
A case where the retardation expression layer is a stretched film will be described. The stretched film is usually obtained by stretching the base material. As a method of stretching the base material, for example, a roll (winding body) in which the base material is wound on a roll is prepared, and the base material is continuously unwound and unwound from the winding body. The base material is transferred to the heating furnace. The set temperature of the heating furnace is in the range of the base material near the glass transition temperature (° C) to [glass transition temperature +100] (° C), preferably near the glass transition temperature (° C) to [glass transition temperature +50] (° C). The range of. In the heating furnace, when the base material is stretched in the traveling direction or in the direction orthogonal to the traveling direction, the transport direction and tension are adjusted and the base material is inclined at an arbitrary angle to perform uniaxial or biaxial thermal stretching treatment. Do. The stretching ratio is usually 1.1 to 6 times, preferably 1.1 to 3.5 times.

Further, the method of stretching in the oblique direction is not particularly limited as long as the orientation axis can be continuously tilted to a desired angle, and a known stretching method can be adopted. Examples of such a stretching method include the methods described in JP-A-50-83482 and JP-A-2-113920. When imparting retardation to a film by stretching, the thickness after stretching is determined by the thickness before stretching and the stretching ratio.

The base material is usually a transparent base material. The transparent base material means a base material having transparency capable of transmitting light, particularly visible light, and the transparency means a characteristic that the transmittance for light rays having a wavelength of 380 nm or more and 780 nm or less is 80% or more. To say. Specific examples of the transparent base material include a translucent resin base material. Resins constituting the translucent resin base material include polyolefins such as polyethylene and polypropylene; cyclic olefin resins such as norbornene-based polymers; polyvinyl alcohol; polyethylene terephthalate; polymethacrylic acid ester; polyacrylic acid ester; triacetylcellulose, Cellulose esters such as diacetyl cellulose and cellulose acetate propionate; polyethylene naphthalate; polycarbonate; polysulfone; 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 an esterified part or all of the hydroxyl groups contained in cellulose and can be easily obtained from the market. Cellulose ester substrates are also readily available on the market. Examples of commercially available cellulose ester base materials include "Fujitac (registered trademark) film" (Fujifilm Co., Ltd.); "KC8UX2M", "KC8UY" and "KC4UY" (Konica Minolta Opto Co., Ltd.). ..

Polymethacrylic acid ester and polyacrylic acid ester (hereinafter, polymethacrylic acid ester and polyacrylic acid ester may be collectively referred to as (meth) acrylic resin.

Examples of the (meth) acrylic resin 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 the (meth) acrylic resin, a commercially available general-purpose (meth) acrylic resin can be used. As the (meth) acrylic resin, what is called an impact resistant (meth) acrylic resin may be used.

It is also preferable to include rubber particles in the (meth) acrylic resin in order to further improve the mechanical strength. The rubber particles are preferably acrylic particles. Here, the acrylic rubber particles have rubber elasticity obtained by polymerizing an acrylic monomer containing an acrylic acid alkyl ester as a main component, such as butyl acrylate or 2-ethylhexyl acrylate, in the presence of a polyfunctional monomer. It is a particle. The acrylic rubber particles may be formed by forming such particles having rubber elasticity in a single layer, or may be a multilayer structure having at least one rubber elastic layer. Examples of the multi-layered acrylic rubber particles include those having the above-mentioned particles having rubber elasticity as nuclei and covering them with a hard methacrylic acid alkyl ester polymer, and hard methacrylic acid alkyl ester polymers. The core is made of an acrylic polymer having rubber elasticity as described above, and the hard core is covered with a rubber elastic acrylic polymer, and the periphery thereof is a hard alkyl methacrylic acid ester. Examples thereof include those covered with a system polymer. The rubber particles formed by the elastic layer usually have an average diameter in the range of 50 nm or more and 400 nm or less.

The content of rubber particles in the (meth) acrylic resin is usually 5 parts by mass or more and 50 parts by mass or less per 100 parts by mass of the (meth) acrylic resin. Since the (meth) acrylic resin and the acrylic rubber particles are commercially available in a mixed state, the commercially available products can be used. Examples of commercially available (meth) acrylic resins containing acrylic rubber particles include "HT55X" and "Technoloy S001" sold by Sumitomo Chemical Co., Ltd. "Technoloy S001" is sold in the form of a film.

Cyclic olefin resin is easily available on the market. Commercially available cyclic olefin resins include "Topas" (registered trademark) [Ticona (Germany)], "Arton" (registered trademark) [JSR Co., Ltd.], "ZEONOR" (registered trademark) [Japan. Zeon Co., Ltd.], "ZEONEX" (registered trademark) [Zeon Corporation] and "Apel" (registered trademark) [Mitsui Chemicals Co., Ltd.]. Such a cyclic olefin resin can be used as a base material by forming a film by a known means such as a solvent casting method or a melt extrusion method. Further, a commercially available cyclic olefin resin base material can also be used. Commercially available cyclic olefin resin base materials include "Sushina" (registered trademark) [Sekisui Chemical Co., Ltd.], "SCA40" (registered trademark) [Sekisui Chemical Co., Ltd.], and "Zeonor Film" (registered trademark). ) [Optes Co., Ltd.] and "Arton Film" (registered trademark) [JSR Co., Ltd.].

When the cyclic olefin resin is a copolymer of a cyclic olefin and an aromatic compound having a chain olefin or a vinyl group, the content ratio of the structural unit derived from the cyclic olefin is the total structural unit of the copolymer. On the other hand, it is usually in the range of 50 mol% or less, preferably 15 mol% or more and 50 mol% or less. Examples of the chain olefin include ethylene and propylene, and examples of the aromatic compound 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 the structural unit derived from the chain olefin is the content of the copolymer. The content ratio of the structural unit derived from the aromatic compound having a vinyl group, which is usually 5 mol% or more and 80 mol% or less with respect to the total structural unit, is usually 5 mol with respect to the total structural unit of the copolymer. % Or more and 80 mol% or less. Such a ternary copolymer has an advantage that the amount of expensive cyclic olefin used can be relatively reduced in the production thereof.

(Second cured product layer)
When the retardation layer is composed of the retardation layer 60 of the first retardation layer 30 and the second retardation layer 40, the second cured product layer 50 includes the first retardation layer 30 and the second retardation layer 40. Can be placed for gluing. The thickness of the second cured product layer 50 may be, for example, 20 μm or less, preferably 10 μm or less, and more preferably 5 μm or less. The thickness of the second cured product layer 50 may be, for example, 0.5 μm or more.

The second cured product layer 50 contains a cured product of the active energy ray-curable adhesive composition. As for the active energy ray-curable adhesive composition used for the second cured product layer 50, the above description of the first cured product layer 14 is applied. The active energy ray-curable adhesive composition used for the second cured product layer 50 may not contain either a photosensitizer or a photosensitizer.
The active energy ray-curable adhesive composition contained in the second cured product layer 50 may be of the same or different type as the active energy ray-curable adhesive composition contained in the first cured product layer 14. The second cured product layer 50 is preferably a cured product layer of the cationically polymerizable adhesive composition.

(Storage modulus of the second cured product layer)
The storage elastic modulus of the second cured product layer at a temperature of 30 ° C. is preferably 300 MPa or more, more preferably 500 MPa or more, and more preferably 1000 MPa or more, from the viewpoint of suppressing retardation cracks during processing. More preferred. Further, it is preferably 5000 MPa or less, more preferably 4000 MPa or less, and further preferably 3500 MPa or less. The storage elastic modulus of the second cured product layer is measured by the method described in the section of Examples described later.
_{The storage elastic modulus (E 2} ) of the second cured product layer at a temperature of 80 ° C. is preferably 20 MPa or more, more preferably 30 MPa or more, and more preferably 40 MPa or more, from the viewpoint of suppressing corrosion of the conductive layer. Is even more preferable. Further, it is preferably 100 MPa or less, more preferably 90 MPa or less, and further preferably 80 MPa or less. The storage elastic modulus (E ₂ ) of the second cured product layer is measured by the method described in the section of Examples described later.

(Glass transition temperature of the second cured product layer)
The glass transition temperature (Tg ₂ ) of the second cured product layer is preferably 200 ° C. or lower, more preferably 150 ° C. or lower, and 120 ° C. or lower, from the viewpoint of suppressing retardation cracks during processing. It is more preferable to have. Further, it is preferably 40 ° C. or higher, more preferably 50 ° C. or higher, further preferably 60 ° C. or higher, and particularly preferably 70 ° C. or higher. The glass transition temperature (Tg ₂ ) of the second cured product layer is measured by the method described in the section of Examples described later.

(Adhesive layer)
The laminate 100 has an adhesive layer 70 on the opposite side of the retardation layer 20 from the first cured product layer 14. The pressure-sensitive adhesive layer can be composed of a pressure-sensitive adhesive composition containing a resin as a main component, such as (meth) acrylic-based, rubber-based, urethane-based, ester-based, silicone-based, and polyvinyl ether-based. Among them, a pressure-sensitive adhesive composition using a (meth) acrylic resin having excellent transparency, weather resistance, heat resistance and the like as a base polymer is preferable. The pressure-sensitive adhesive composition may be an active energy ray-curable type or a thermosetting type. The thickness of the pressure-sensitive adhesive layer is usually 3 μm or more and 30 μm or less, preferably 3 μm or more and 25 μm or less.

Examples of the (meth) acrylic resin (base polymer) used in the pressure-sensitive adhesive composition include butyl (meth) acrylate, ethyl (meth) acrylate, isooctyl (meth) acrylate, and 2- (meth) acrylate. A polymer or copolymer containing one or more (meth) acrylic acid esters such as ethylhexyl as a monomer is preferably used. It is preferable that the base polymer is copolymerized with a polar monomer. Examples of the polar monomer include (meth) acrylic acid, 2-hydroxypropyl (meth) acrylate, hydroxyethyl (meth) acrylate, (meth) acrylamide, N, N-dimethylaminoethyl (meth) acrylate, and glycidyl (). Examples thereof include monomers having a carboxyl group, a hydroxyl group, an amide group, an amino group, an epoxy group, and the like, such as meth) acrylate.

The pressure-sensitive adhesive composition may contain only the above-mentioned base polymer, but usually further contains a cross-linking agent. The cross-linking agent is a divalent or higher metal ion that forms a carboxylic acid metal salt with a carboxyl group; a polyamine compound that forms an amide bond with a carboxyl group; poly. Epoxy compounds and polyols that form an ester bond with a carboxyl group; polyisocyanate compounds that form an amide bond with a carboxyl group are exemplified. Of these, polyisocyanate compounds are preferable.

In one aspect of the present invention, the amount of iodine in the pressure-sensitive adhesive layer after the optical laminate is stored at a temperature of 80 ° C. and a relative humidity of 90% for 250 hours is 900 mg / kg or less. The amount of iodine contained in the pressure-sensitive adhesive layer can be measured by the method described in Examples. The iodine content refers to the content of the iodine element in the pressure-sensitive adhesive layer.
When the amount of iodine contained in the pressure-sensitive adhesive layer is 900 mg / kg or less, corrosion of the conductive layer can be suppressed. The amount of iodine contained in the pressure-sensitive adhesive layer is preferably 800 mg / kg or less, more preferably 700 mg / kg or less.

(Manufacturing method of laminated body)
An example of the method for producing the laminate of the present invention will be described with reference to FIG. As shown in FIG. 3A, a linear polarizing plate 10 in which a polarizing element 13 and a thermoplastic resin film 11 are laminated via an adhesive layer 12 is produced. As shown in FIG. 3B, the first retardation layer 30 including the first retardation expression layer 31, the first alignment layer 32 and the first base material layer 33, the second retardation expression layer 43, and the second orientation. The second retardation layer 40 including the layer 42 and the second base material layer 41 is laminated via the second cured product layer 50, and as shown in FIG. 3C, the first base material layer 33 and the first base material layer 33 are laminated. A retardation layer laminate in which the alignment layer 32, the first retardation expression layer 31, the second cured product layer 50, the second retardation expression layer 43, the second alignment layer 42, and the second base material layer 41 are laminated in this order. 60 is made. As shown in FIG. 3D, the polarizer 13 side of the linear polarizing plate 10 and the first retardation layer 30 side of the retardation layer laminate 60 are laminated via the first cured product layer 14, and the laminate is formed. Get 80.

As a method of adhering the polarizer 13 and the thermoplastic resin film 11, an adhesive composition is applied to either or both of the binder 13 and the bonding surface of the thermoplastic resin film 11, and the other is coated. A method of laminating the bonded surfaces of the above and curing the adhesive composition constituting the adhesive layer 12 can be mentioned.

As a method of adhering the first retardation layer 30 and the second retardation layer 40, it is active on either or both of the bonding surface of the first retardation layer 30 and the bonding surface of the second retardation layer 40. Examples thereof include a method in which an energy ray-curable adhesive composition is applied, the other bonded surface is laminated thereto, and the active energy ray-curable adhesive constituting the second cured product layer 50 is cured. The active energy ray for curing the active energy ray-curable adhesive constituting the second cured product layer 50 is irradiated from one or both sides of the first retardation layer 30 and the second retardation layer 40. be able to.

As a method of adhering the linear polarizing plate 10 and the retardation layer laminate 60, an active energy ray-curable type is applied to either or both of the bonding surface of the linear polarizing plate 10 and the retardation layer laminate 60. Examples thereof include a method of applying an adhesive composition, laminating the other bonded surface on the adhesive composition, and curing the active energy ray-curable adhesive constituting the first cured product layer 14. From the viewpoint of adhesion, the active energy ray-curable adhesive composition is preferably applied only to the bonded surface of the retardation layer laminate 60. The active energy ray for curing the active energy ray-curable adhesive constituting the first cured product layer 14 may be irradiated from either one or both sides of the linear polarizing plate 10 and the retardation layer laminate 60. it can.

Corona treatment, plasma treatment, etc. may be performed on either or both of the bonded surfaces, or a primer layer may be formed. For coating the water-based adhesive composition and the active energy ray-curable adhesive composition, various coating methods such as a doctor blade, a wire bar, a die coater, a comma coater, and a gravure coater can be used.

The laminate of the present invention may be a laminate containing the laminate 80 and the pressure-sensitive adhesive layer shown in FIG. 3 (D) (the pressure-sensitive adhesive layer is laminated on the second retardation layer 40 side). Further, even if the laminate includes a laminate obtained by peeling at least one of the first substrate layer 33 and the second substrate layer 41 from the laminate 80 shown in FIG. 3 (D) and an adhesive layer. Good. Further, it may be a laminate in which the first base material layer 33 and the first alignment layer 32 are peeled off from the laminate 80 shown in FIG. 3 (D), and a laminate including an adhesive layer, and FIG. 3 It may be a laminate including a laminate in which the second base material layer 41 and the second orientation layer 42 are peeled off from the laminate 80 shown in (D) and an adhesive layer.

(Conductive layer)
The optical laminate of the present invention can be laminated on the conductive layer formed on the substrate on the pressure-sensitive adhesive layer 70 side. The conductive layer may be, for example, a conductive transparent metal oxide layer or a metal layer wiring layer.

Examples of the conductive transparent metal oxide layer include ITO (tin-doped indium oxide) and AZO (aluminum-doped zinc oxide).

The metal constituting the metal wiring layer contains, for example, aluminum, copper, silver, iron, tin, zinc, platinum, nickel, molybdenum, chromium, tungsten, lead, titanium, palladium, indium, and two or more of these metals. It may be a layer containing at least one metal element selected from the alloys to be used. Of these, a layer containing at least one metal element selected from aluminum, copper, silver and gold is preferable from the viewpoint of conductivity, and more preferably contains an aluminum element from the viewpoint of conductivity and cost. It is a layer. When the layer contains copper, it may be blackened from the viewpoint of preventing light reflection. The blackening treatment is to oxidize the surface of the conductive layer to precipitate _{Cu 2 O or Cu O.}
Further, the conductive layer may be, for example, a layer containing graphene, zinc oxide or the like.

The conductive layer is provided on the substrate, for example. Examples of the method for forming the conductive layer on the substrate include a sputtering method. The substrate may be a transparent substrate constituting a liquid crystal cell included in the touch input element, or may be a glass substrate. The transparent substrate may be formed of, for example, polyethylene terephthalate, polycarbonate, polymethyl methacrylate, polyethylene naphthalate, polyether sulfone, cyclic olefin copolymer, triacetyl cellulose, polyvinyl alcohol, polyimide, polystyrene, biaxially stretched polystyrene or the like. The glass substrate may be made of, for example, soda lime glass, low-alkali glass, non-alkali glass, or the like. The conductive layer may be formed on the entire surface of the substrate, or may be formed on a part thereof.

Examples of the metal wiring layer include a metal mesh, which is a thin metal wiring layer, metal nanoparticles, and a layer in which metal nanowires are added to a binder. The metal mesh indicates a two-dimensional network structure formed of metal wiring. The shape of the metal mesh opening (opening between wires or mesh) is not particularly limited, and may be, for example, a polygon (triangle, quadrangle, pentagon, hexagon, etc.), a circle, an ellipse, or an indefinite shape. The openings may be the same or different. In a preferred embodiment, the metal mesh openings have the same shape and are square or rectangular, respectively.

When the conductive layer is a metal wiring layer (particularly a metal mesh), the metal wiring may be arranged at predetermined intervals in the vertical and horizontal directions of a plane on the substrate, for example. At this time, the opening may be filled with a resin (adhesive or the like), or a metal wiring layer may be embedded in the resin (adhesive or the like). When resin or the like is used, the conductive layer is composed of both metal wiring and resin (adhesive).

The line width of the metal wiring (particularly metal mesh) is usually 10 μm or less, preferably 5 μm or less, more preferably 3 μm or less, usually 0.1 μm or more, preferably 0.5 μm or more, and more preferably 1 μm or more. The line width of the metal wiring layer may be a combination of these upper limit values and lower limit values, and is preferably 0.5 to 5 μm, more preferably 1 to 3 μm.

The thickness of the conductive layer (conductive transparent metal oxide layer or metal wiring layer) is not particularly limited, but is usually 10 μm or less, preferably 3 μm or less, more preferably 1 μm or less, and particularly preferably 0.5 μm or less. It is usually 0.01 μm or more, preferably 0.05 μm or more, and more preferably 0.1 μm or more. The thickness of the conductive layer may be a combination of these upper limit values and lower limit values, and is preferably 0.01 to 3 μm, more preferably 0.05 to 1 μm. When the conductive layer is a metal wiring layer and the metal wiring layer is composed of both a resin (adhesive or the like) and a metal wiring, the thickness of the conductive layer is the thickness including the resin.

The method for preparing the conductive layer is not particularly limited, and may be metal foil lamination, such as vacuum deposition method, sputtering method, wet coating, ion plating method, inkjet printing method, gravure printing method, electrolytic plating, and electroless plating. Although it may be formed by sputtering, it is preferably a conductive layer formed by a sputtering method, an inkjet printing method, or a gravure printing method, and more preferably a conductive layer formed by sputtering.

The conductive layer (for example, a metal mesh) may have a function of generating a signal when a transparent substrate is touched on a touch panel and transmitting the touch coordinates to an integrated circuit or the like.

An optical laminate provided with a conductive layer (for example, a conductive transparent metal oxide layer, a metal wiring layer, etc.) is useful because it can be used for a touch input type liquid crystal display device having a touch panel function, but it is a polarizer. The dichroic dye (iodine) contained in the above moves to the conductive layer, and the conductive layer is easily corroded. In particular, when a metal wiring layer such as a metal mesh is used, the conductive layer is more likely to be corroded because the line width is narrow. However, the optical laminate of the present invention can effectively suppress the movement of the dichroic dye to the conductive layer and effectively prevent the corrosion of the conductive layer.

(Use)
The laminate can be used in an image display device. 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 emitting source. The image display device includes a liquid crystal display device, an organic electroluminescence (EL) display device, an inorganic electroluminescence (EL) display device, a touch panel display device, an electron emission display device (for example, an electric field emission display device (FED), a surface electric field emission display). Device (SED)), electronic paper (display device using electronic ink or electrophoresis element, plasma display device, projection type display device (for example, grating light valve (GLV) display device, display with digital micromirror device (DMD)) Devices) and piezoelectric ceramic displays, etc. Examples of the liquid crystal display device include any of a transmissive liquid crystal display device, a transflective liquid crystal display device, a reflective liquid crystal display device, a direct-view type liquid crystal display device, and a projection type liquid crystal display device. These image display devices may be an image display device that displays a two-dimensional image, or may be a three-dimensional image display device that displays a three-dimensional image. In particular, a polarizing plate that is a circular polarizing plate. The composite can be effectively used in an organic electroluminescence (EL) display device which may include an image display panel having a bent portion.

The optical laminate can function as a circularly polarizing plate and an antireflection film. The optical laminate can be arranged on the viewing side of the image display layer panel in a direction in which the polarizing film is located on the viewing side. The laminate is suitable as a circularly polarizing plate or an antireflection film used in an in-vehicle image display device.

Hereinafter, the present invention will be described in more detail with reference to Examples. Unless otherwise specified, "%" and "part" in the example are mass% and parts by mass.

(Evaluation of metal corrosion resistance)
The laminates obtained in Examples and Comparative Examples were cut into test pieces having a size of 25 mm × 50 mm and attached to the metal layer side of the glass substrate with a metal layer via an adhesive layer. As the glass substrate with a metal layer, a glass substrate (manufactured by Geomatec Co., Ltd.) in which a metal-aluminum layer having a thickness of about 500 nm was laminated on a non-alkali glass surface by sputtering was used. The obtained optical laminate was stored in an oven at a temperature of 85 ° C. and a relative humidity of 85% for 250 hours, and then the state of the metal layer on the portion to which the optical laminate was attached was irradiated with light from the back surface of the glass substrate. Observation was performed from the surface of the polarizing plate through a magnifying glass, and the occurrence of pore erosion (generation of pores having a diameter of 0.1 mm or more and capable of transmitting light) was evaluated according to the following criteria. The results are shown in Tables 2 and 4.

⊚: The number of pitting corrosion generated on the surface of the metal layer is 4 or less.
◯: The number of pitting corrosion generated on the surface of the metal layer is 10 or less.
X: A large number of pitting corrosions occur on the front surface of the metal layer surface.

(Evaluation of the amount of iodine in the adhesive layer)
The optical laminates obtained in Examples and Comparative Examples were cut into test pieces having a size of 25 mm × 50 mm and attached to non-alkali glass (EAGLE XG manufactured by Corning Inc.) via an adhesive layer. The optical laminate attached to the glass was stored in an oven at a temperature of 80 ° C. and a relative humidity of 90% for 250 hours. Then, the optical laminate was peeled off from the glass and only the adhesive was scraped off. From the obtained pressure-sensitive adhesive, the amount of iodine (mg / kg) contained in the pressure-sensitive adhesive was quantified by using an oxidation combustion ion chromatograph method under the following equipment and conditions. The results are shown in Tables 2 and 4.

(1) Sample combustion / equipment: AQF-2100H manufactured by Mitsubishi Chemical Analytech Co., Ltd.
・ Combustion conditions Combustion temperature: 1100 ℃
Gas flow rate: Argon flow rate = 200 mL / min,
Oxygen flow rate = 400 mL / min,
Humidifying Air flow rate = 100 mL / min (2) Ion chromatograph / device: Thermo Fisher Scientific's Integration
-Column: IonPac AS19 manufactured by Thermo Fisher Scientific
-Measurement conditions Eluent: KOH gradient Flow velocity: 1.0 mL / min Injection volume: 100 μL
Measurement mode: Suppressor type detector: Electrical conductivity

(Adhesion measurement)
The laminates produced in Examples and Comparative Examples were cut into a size of 200 mm in length and 25 mm in width, and the pressure-sensitive adhesive layer surface was bonded to a soda glass substrate.
Next, insert a cutter blade between the polarizer and the λ / 2 retardation layer, peel off 30 mm from the end in the length direction, and peel off the peeled part with a universal tensile tester ["AG-1" manufactured by Shimadzu Corporation. I grabbed it at the part of "]. The test piece in this state was subjected to JIS K 6854-2: 1999 "Adhesive-Peeling Adhesive Strength Test Method-Part 2: 180 ° Peeling" in an atmosphere at a temperature of 23 ° C. and a relative humidity of 55%. A 180-degree peeling test was performed at a gripping movement speed of 300 mm / min, and an average peeling force over a length of 170 mm excluding 30 mm of the gripped portion was obtained and evaluated based on the following criteria. The results are shown in Tables 2 and 4.
〇: 180 ° peeling force is 1.0N or more Δ: 180 ° peeling force is 0.5N or more and less than 1.0N

(Measurement of storage elastic modulus and glass transition temperature of adhesive layer at 80 ° C)
One side of a cyclic polyolefin resin film having a thickness of 50 μm is coated with any of the adhesives 1 to 5 described below using a coating machine [Barcoater, manufactured by Daiichi Rika Co., Ltd.], and the coated surface is coated. Further, a cyclic polyolefin resin film having a thickness of 50 μm was laminated. Next, the adhesive layer was cured by irradiating with ultraviolet rays so that ^{the integrated light amount was 1500 mJ / cm 2} (UVB) by a "D bulb" manufactured by Fusion UV Systems. This was cut into a size of 5 mm × 30 mm, and the cyclic polyolefin resin film was peeled off to obtain a cured film of an adhesive. This cured film is gripped with a dynamic viscoelasticity measuring device "DVA-220" manufactured by IT Measurement Control Co., Ltd. at a distance of 2 cm between grippers so that the long side thereof is in the tensile direction, and tension and contraction are performed. The frequency was set to 10 Hz and the temperature rising rate was set to 10 ° C./min, and measurements were performed in the temperature range of 25 ° C. to 200 ° C. to determine the storage elastic modulus at a temperature of 80 ° C. Further, in the results obtained in the above measurement, the glass transition temperature The temperature at which the value of the storage modulus (E _A) and the loss modulus ratio _{(E B) (E B /} E A) is the maximum value did. The results are shown in Tables 1 and 3.

(Evaluation of moisture permeability)
A film with an adhesive layer having an acrylic pressure-sensitive adhesive layer 1 having a thickness of 5 μm formed on the surface of a triacetyl cellulose film having a thickness of 20 μm was prepared. Moisture permeability at a temperature 80 ° C. and 90% relative humidity of the pressure-sensitive with adhesive layer film was ^{5200 [g / (m 2 ·} 24hr)].
After applying the adhesive 1 to the surface of the acrylic pressure-sensitive adhesive layer 1, the coating layer is cured by irradiating the coating layer with ultraviolet rays to form a 30 μm adhesive layer 1 and a 30 μm adhesive layer 1/5 μm acrylic pressure-sensitive adhesive. A laminated body having a laminated structure of a triacetyl cellulose film having a agent layer of 1/20 μm was obtained.
The resulting laminate, the cup method defined in JIS Z 0208, temperature 40 ° C., was measured moisture permeability at 90% relative humidity ^[g / (m 2 · 24hr)]. Adhesive 1 was changed to adhesives 2 to 5, and the moisture permeability of each adhesive was measured. The results are shown in Tables 1 and 3.

(Preparation of active energy ray-curable adhesive composition)
Each component shown in Table 1 was mixed at the blending ratio (unit: parts by mass) shown in Table 1 and then defoamed to prepare an active energy ray-curable adhesive composition (adhesives 1 and 2). .. The cationic polymerization initiator (B-1) was blended as a 50% propylene carbonate solution, and Table 1 shows the solid content thereof.

(Cation-polymerizable compound (A))
A-1: 3', 4'-epoxycyclohexylmethyl 3,4-epoxycyclohexanecarboxylate (trade name: CEL2021P, manufactured by Daicel Corporation)
A-2: 1,2-Epoxy-4- (2-oxylanyl) cyclohexane adduct of 2,2-bis (hydroxymethyl) -1-butanol (trade name: EHPE3150, manufactured by Daicel Corporation)
A-3: Neopentyl glycol diglycidyl ether (trade name: EX-211L, manufactured by Nagase ChemteX Corporation)
A-4: 3-Ethyl-3 {[(3-ethyloxetane-3-yl) methoxy] methyl} oxetane (trade name: OXT-221, manufactured by Toa Synthetic Co., Ltd.)
A-5: Bisphenol A type epoxy resin (trade name: EP-4100E, ADEKA Corporation, viscosity 13 Pa · s (temperature 25 ° C))
A-6: Aromatic-containing oxetane compound (trade name: TCM-104, manufactured by TRONLY)
(Photocationic polymerization initiator (B))
B-1: CPI-100P, manufactured by Sun Appro Co., Ltd., 50% by mass solution (photosensitizer (C))
C-1: 1,4-diethoxynaphthalene

(Manufacturing of linear polarizing plate 1)
A polyvinyl alcohol film having a thickness of 20 μm, a degree of polymerization of 2,400, and a saponification degree of 99.9% or more was uniaxially stretched on a roll heated to 125 ° C. at a draw ratio of 4.5 times, and maintained in a tense state, 28. After immersing in water at ° C. for 30 seconds, it was immersed in a dyeing bath at 28 ° C. containing 0.05 parts by mass of iodine and 5 parts by mass of potassium iodide per 100 parts by mass of water for 30 seconds.
Then, it was immersed in a boric acid aqueous solution 1 at 64 ° C. containing 5.5 parts by mass of boric acid and 15 parts by mass of potassium iodide per 100 parts by mass of water for 110 seconds.
Then, it was immersed in a boric acid aqueous solution 2 at 67 ° C. containing 2.35 parts by mass of boric acid and 15 parts by mass of potassium iodide per 100 parts by mass of water for 30 seconds.
Then, it was washed with pure water at 10 ° C. and dried at 80 ° C. to obtain a polarizing film.
The thickness of the obtained polarizing film was 7 μm.

Further, a cycloolefin film (COP film) with a hard coat layer having a thickness of 25 μm was attached to one side of the obtained polarizing film via an aqueous adhesive, dried at 90 ° C., and the COP film / aqueous adhesive (adhesive) was applied. A linear polarizing plate 1 having a laminated structure of agent layer) / polarizer was obtained.

(Manufacturing of linear polarizing plate 2)
Lamination of COP film / water-based adhesive (adhesive layer) / polarizer in the same manner as in the production of the linear polarizing plate 1 except that the boric acid content in the boric acid aqueous solution 2 was changed to 5.5 parts by mass. A linear polarizing plate 2 having a structure was obtained.

(Manufacturing of λ / 2 retardation layer)
A λ / 2 alignment treatment was performed by applying an alignment film coating liquid to a transparent resin base material and drying it. Next, a coating liquid containing a discotic liquid crystal compound is applied to the alignment surface, and the orientation of the liquid crystal compound is fixed by heating and UV irradiation. Was produced.

(Manufacturing of λ / 4 retardation layer)
A transparent resin base material for λ / 4 alignment, which has been rubbed with an alignment film, is coated with a coating liquid containing a rod-shaped and polymerizable nematic liquid crystal monomer and solidified while maintaining refractive index anisotropy. A retardation-expressing layer having a thickness of 1 μm was obtained on the substrate.

(Manufacturing of retardation layer laminate)
The liquid crystal layer side of the λ / 2 retardation layer and the λ / 4 retardation layer was subjected to corona treatment. Arrange so that the angle formed by the slow axis of the λ / 2 retardation layer and the slow axis of the λ / 4 retardation layer is 60 °, and use the adhesive 1 so that the thickness of the adhesive is 3 μm. The liquid crystal layers were bonded to each other with a laminator to obtain a laminated body.
^{From the λ / 4 retardation layer side of the obtained laminate, ultraviolet irradiation was performed with an integrated light amount of 400 mJ / cm 2} (UV-B) using an ultraviolet irradiation device [manufactured by Fusion UV Systems Co., Ltd.], and the above-mentioned adhesion was performed. Agent 1 is cured to form a second cured product layer, which is "λ / 2 retardation layer" (first retardation layer) / adhesive layer (second cured product layer) / "λ / 4 retardation layer" (first A retardation layer laminate having a laminated structure of two retardation layers) was obtained.

<Example 1>
The alignment film on the λ / 2 retardation layer side and the transparent resin base material of the obtained retardation layer laminate are peeled off, and the surface of the linear polarizing plate 1 opposite to the thermoplastic resin film and the λ / 2 retardation The liquid crystal layer of the layer was bonded to each other using the adhesive 2. The thickness of the first cured product layer made of the adhesive 2 was 3 μm, and the angle formed by the transmission axis of the polarizer and the slow axis of the λ / 2 retardation layer was 15 °.
Next, the alignment film on the λ / 4 retardation layer side and the transparent resin base material are peeled off, and the thermoplastic resin film / water-based adhesive (adhesive layer) / polarizer / first cured product layer / "λ / 2 retardation" A laminated body having a laminated structure of "layer" (first retardation layer) / second cured product layer / "λ / 4 retardation layer" (second retardation layer) was obtained. An acrylic pressure-sensitive adhesive layer 1 having a thickness of 15 μm was laminated on the surface of the second retardation layer of the obtained laminate to obtain the laminate of Example 1. The obtained laminate was evaluated for metal corrosion resistance, the amount of iodine in the pressure-sensitive adhesive layer, and adhesion. The results are shown in Table 2.

<Comparative example 1>
The alignment film on the λ / 2 retardation layer side and the transparent resin base material of the obtained retardation layer laminate are peeled off, and the surface of the linear polarizing plate 1 opposite to the thermoplastic resin film and the λ / 2 phase difference. The liquid crystal layer of the layer was bonded to each other using an acrylic pressure-sensitive adhesive layer 2 having a thickness of 5 μm (storage elastic modulus at a temperature of 80 ° C. of 0.5 MPa, glass transition temperature of −45 ° C.). The angle formed by the transmission axis of the polarizer and the slow axis of the λ / 2 retardation layer was 15 °.
Next, the alignment film on the λ / 4 retardation layer side and the transparent resin base material are peeled off, and the thermoplastic resin film / water-based adhesive (adhesive layer) / polarizer / adhesive layer / "λ / 2 retardation layer" A laminated body having a laminated structure of (first retardation layer) / second cured product layer / "λ / 4 retardation layer" (second retardation layer) was obtained. An acrylic pressure-sensitive adhesive layer 1 having a thickness of 15 μm was laminated on the surface of the second retardation layer of the obtained laminate to obtain a laminate of Comparative Example 1. The obtained laminate was evaluated for metal corrosion resistance, the amount of iodine in the pressure-sensitive adhesive layer, and adhesion. The results are shown in Table 2.

(Preparation of active energy ray-curable adhesive composition)
Each component shown in Table 3 was mixed at the blending ratio (unit: parts by mass) shown in Table 3 and then defoamed to prepare an active energy ray-curable adhesive composition (adhesives 3 to 5). .. The cationic polymerization initiator (B-2) was blended as a 50% propylene carbonate solution, and Table 3 shows the solid content thereof.

(Cation-polymerizable compound (A))
A-7: 3', 4'-epoxycyclohexylmethyl 3,4-epoxycyclohexanecarboxylate (trade name: CEL2021P, manufactured by Daicel Corporation)
A-8: 2,2-bis (hydroxymethyl) -1-butanol 1,2-epoxy-4- (2-oxylanyl) cyclohexane adduct (trade name: EHPE3150, manufactured by Daicel Corporation)
A-9: Neopentyl glycol diglycidyl ether (trade name: ED-523T, manufactured by ADEKA Corporation)
A-10: 3-Ethyl-3 {[(3-ethyloxetane-3-yl) methoxy] methyl} oxetane (trade name: OXT-221, manufactured by Toa Synthetic Co., Ltd.)
A-111: Compound represented by the following formula

(Photocationic polymerization initiator (B))
B-2: CPI-100P, manufactured by Sun Appro Co., Ltd., 50% by mass solution (photosensitizer (C))
C-2: 1,4-diethoxynaphthalene

<Examples 2 to 4>
A laminate was obtained in the same manner as in Example 1 except that the adhesive 2 was replaced with the adhesives 3 to 5. The obtained laminate was evaluated for metal corrosion resistance, the amount of iodine in the pressure-sensitive adhesive layer, and adhesion. The results are shown in Table 4.
The laminate of Example 2 is a thermoplastic resin film / water-based adhesive (adhesive layer) / polarizer / first cured product layer (cured product layer of adhesive 3) / "λ / 2 retardation layer". It has a laminated structure of (first retardation layer) / second cured product layer (cured product layer of adhesive 1) / "λ / 4 retardation layer" (second retardation layer) / 15 μm pressure-sensitive adhesive layer.
The laminate of Example 3 is a thermoplastic resin film / water-based adhesive (adhesive layer) / polarizer / first cured product layer (cured product layer of adhesive 4) / "λ / 2 retardation layer" (first It has a laminated structure of 1 retardation layer) / second cured product layer (cured product layer of adhesive 1) / "λ / 4 retardation layer" (second retardation layer) / 15 μm pressure-sensitive adhesive layer.
The laminate of Example 4 is a thermoplastic resin film / water-based adhesive (adhesive layer) / polarizer / first cured product layer (cured product layer of adhesive 5) / "λ / 2 retardation layer" (first It has a laminated structure of 1 retardation layer) / second cured product layer (cured product layer of adhesive 1) / "λ / 4 retardation layer" (second retardation layer) / 15 μm pressure-sensitive adhesive layer.

<Comparative example 2>
A laminate was obtained in the same manner as in Example 1 except that the adhesive 2 was replaced with the adhesive 1. The obtained laminate was evaluated for metal corrosion resistance, the amount of iodine in the pressure-sensitive adhesive layer, and adhesion. The results are shown in Table 4.
The laminate of Comparative Example 2 is a thermoplastic resin film / water-based adhesive (adhesive layer) / polarizer / first cured product layer (cured product layer of adhesive 1) / "λ / 2 retardation layer". It has a laminated structure of (first retardation layer) / second cured product layer (cured product layer of adhesive 1) / "λ / 4 retardation layer" (second retardation layer) / 15 μm pressure-sensitive adhesive layer.

10 linear polarizing plate, 11 thermoplastic resin film, 12 adhesive layer, 13 polarizer, 14 first cured product layer, 20 retardation layer, 30 first retardation layer, 31 retardation expression layer, 32 orientation layer, 33 Base material layer, 40 second retardation layer, 41 base material layer, 42 alignment layer, 43 retardation expression layer, 50 second cured product layer, 60 retardation laminate, 70 adhesive layer, 80 optical laminate, 100 Optical laminate

Claims (16)

1. An optical laminate including a polarizer, a first cured product layer, a retardation layer, and an adhesive layer in this order.
   The polarizer is made of a polyvinyl alcohol resin containing iodine.
   The first cured product layer is a cured product of an active energy curable composition.
   The retardation layer contains at least one retardation expression layer which is a polymer of a polymerizable liquid crystal compound.
   The pressure-sensitive adhesive layer has an iodine content of 900 mg / kg or less after the optical laminate is stored at a temperature of 80 ° C. and a relative humidity of 90% for 250 hours.
   The polarizer and the first cured product layer are in direct contact with each other.
   An optical laminate in which the first cured product layer and the retardation layer are in direct contact with each other.
2. The retardation layer is a layer containing the first polymerized layer, the second cured product layer, and the second polymerized layer in this order from the first cured product layer side.
   The optical laminate according to claim 1, wherein the first polymerized layer and the second polymerized layer contain a polymer of a polymerizable liquid crystal compound independently of each other.
3. The optical laminate according to claim 2, wherein the second cured product layer is an active energy ray-cured product layer.
4. Temperature 80 ° C. and 90% relative humidity moisture permeability of the first cured layer in a thickness 30μm is ^{1500 [g / (m 2 ·} 24hr)] Hereinafter, the optical laminate according to any one of claims 1 to 3 body.
5. An optical laminate including a polarizer, a first cured product layer, a first retardation layer, a second cured product layer, a second retardation layer, and an adhesive layer in this order.
   The polarizer is made of a polyvinyl alcohol resin containing iodine.
   The first retardation layer and the second retardation layer contain a retardation expression layer containing a polymer of a polymerizable liquid crystal compound independently of each other.
   The first cured product layer and the second cured product layer contain the cured product of the active energy ray-curable composition independently of each other.
   The storage elastic modulus of the first cured product layer at a temperature of 80 ° C. is 300 MPa or more.
   The polarizer and the first cured product layer are in direct contact with each other.
   An optical laminate in which the first cured product layer and the first retardation layer are in direct contact with each other.
6. The optical laminate according to claim 5, wherein the second cured product layer has a storage elastic modulus of 20 MPa or more at a temperature of 80 ° C.
7. The optics according to claim 5 or 6, wherein the storage elastic modulus (E ₁ ) of the first cured product layer at a temperature of 80 ° C. is _{larger than the storage elastic modulus (E 2) of the second cured product layer at a temperature of 80 ° C.} Laminated body.
8. Temperature 80 ° C. and 90% relative humidity moisture permeability of the first cured layer in a thickness 30μm is ^{1500 [g / (m 2 ·} 24hr)] Hereinafter, the optical laminate according to any one of claims 5-7 body.
9. An optical laminate including a polarizer, a first cured product layer, a first retardation layer, a second cured product layer, a second retardation layer, and an adhesive layer in this order.
   The polarizer is made of a polyvinyl alcohol resin containing iodine.
   The first retardation layer and the second retardation layer contain a retardation expression layer which is a polymer of a polymerizable liquid crystal compound independently of each other.
   The first cured product layer and the second cured product layer are independently cured products of an active energy ray-curable composition.
   The glass transition temperature (Tg ₁ ) of the first cured product layer is more than 60 ° C.
   The polarizer and the first cured product layer are in direct contact with each other.
   An optical laminate in which the first cured product layer and the first retardation layer are in direct contact with each other.
10. The optical laminate according to claim 9, wherein the glass transition temperature (Tg _{2) of the second cured product layer is 40 ° C. or higher.}
11. The optical laminate according to claim 9 or 10, wherein the glass transition temperature (Tg ₁ ) of the first cured product layer is _{higher than the glass transition temperature (Tg 2) of the second cured product layer.}
12. Temperature 80 ° C. and 90% relative humidity moisture permeability of the first cured layer in a thickness 30μm is ^{1500 [g / (m 2 ·} 24hr)] Hereinafter, the optical laminate according to any one of claims 9-11 body.
13. An optical laminate including a polarizer, a first cured product layer, a retardation layer, and an adhesive layer in this order.
    The polarizer is made of a polyvinyl alcohol resin containing iodine.
    The retardation layer includes a retardation expression layer containing a polymer of a polymerizable liquid crystal compound.
    The first cured product layer is a cured product of an active energy curable composition.
    The active energy ray-curable composition is an optical laminate containing an epoxy compound (A2-1) containing a tricyclic condensed ring and two glycidyl ether groups in the molecule.
14. An optical laminate including a polarizer, a first cured product layer, a first retardation layer, a second cured product layer, a second retardation layer, and an adhesive layer in this order.
    The polarizer is made of a polyvinyl alcohol resin containing iodine.
    The one cured product layer is a cured product of an active energy curable composition.
    The active energy ray-curable composition is an optical laminate containing an epoxy compound (A2-1) containing a tricyclic condensed ring and two glycidyl ether groups in the molecule.
15. An active energy ray-curable composition containing a curable component (A) and a photopolymerization initiator (B).
    The curable component (A) contains a polyfunctional oxetane compound (A5-1) and an epoxy compound (A2-1) containing a tricyclic condensed ring and a diglycidyl ether group in the molecule.
    Active energy rays in which the content of the polyfunctional oxetane compound (A5-1) is higher than the content of the epoxy compound (A2-1) containing the tricyclic condensed ring and two glycidyl ether groups in the molecule. Curable composition.
16. The content ratio (mass ratio) of the polyfunctional oxetane compound (A5-1), the tricyclic condensed ring, and the epoxy compound (A2-1) containing two glycidyl ether groups in the molecule is the polyfunctionality. The oxetane compound (A5-1) / an epoxy compound (A2-1) containing the three-ring condensed ring and two glycidyl ether groups in the molecule = 1.5 / 1 to 5/1 according to claim 15. The active energy ray-curable composition according to the above.

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