CN114902096A

CN114902096A - Optical laminate

Info

Publication number: CN114902096A
Application number: CN202080090355.8A
Authority: CN
Inventors: 永安智; 朴松熙
Original assignee: Sumitomo Chemical Co Ltd
Current assignee: Sumitomo Chemical Co Ltd
Priority date: 2019-12-26
Filing date: 2020-12-22
Publication date: 2022-08-12
Anticipated expiration: 2040-12-22
Also published as: WO2021132236A1; JP2021113969A; TW202132104A; KR20220118536A; CN114902096B

Abstract

The migration of the dichroic dye from the polarizing plate becomes remarkable particularly in an environment of high temperature and high humidity, and therefore an optical laminate capable of preventing the deterioration of the conductive layer due to the transfer of the dichroic dye contained in the polarizing plate to the conductive layer even in an environment of high temperature and high humidity is provided. An optical laminate comprising, in this order, a polarizing plate, a1 st cured product layer, a phase difference layer and an adhesive layer, wherein the polarizing plate is formed from a polyvinyl alcohol resin containing iodine, the 1 st cured product layer is a cured product of an active energy curable composition, the phase difference layer comprises at least one phase difference-developing layer of a polymer which is a polymerizable liquid crystal compound, the amount of iodine in the adhesive layer after the optical laminate is stored at 80 ℃ and 90% relative humidity for 250 hours is 900mg/kg or less, the polarizing plate is in direct contact with the 1 st cured product layer, and the 1 st cured product layer is in direct contact with the phase difference layer.

Description

Optical laminate

Technical Field

The present invention relates to an optical laminate.

Background

In an image display device, a method of disposing an optical layered body having antireflection performance on the viewing side of an image display panel to suppress a reduction in visibility due to reflection of external light is employed.

As an optical laminate having antireflection performance, a circularly polarizing plate having a structure in which a linear polarizing plate having thermoplastic resin films on both surfaces of a polarizer and a retardation layer are laminated via an adhesive layer is known (patent document 1). The circularly polarizing plate is generally laminated on the image display panel by further providing an adhesive layer on the opposite side of the phase difference layer from the linearly polarizing plate.

In recent years, input devices using a circularly polarizing plate and an image display panel having a touch panel function in combination have been widely used in image display devices. A transparent conductive film such as an Indium Tin Oxide (ITO) film or a conductive layer formed of a metal layer such as aluminum is formed on the surface of the image display panel having a touch panel function.

Documents of the prior art

Patent document

Patent document 1: japanese laid-open patent publication No. 2019-197235

Disclosure of Invention

Problems to be solved by the invention

In recent years, circular polarizing plates using linear polarizing plates having a thermoplastic resin film only on one side of a polarizer have been proposed as image display devices are becoming thinner. When the linear polarizing plate having such a structure is laminated on the conductive layer, a dichroic dye (for example, iodine) contained in the polarizing plate may move to the conductive layer, and a malfunction such as poor sensing may occur. Since the migration of the dichroic dye from the polarizing plate becomes remarkable particularly in a high-temperature and high-humidity environment, an optical laminate capable of preventing the deterioration of the conductive layer due to the transfer of the dichroic dye contained in the polarizing plate to the conductive layer even in a high-temperature and high-humidity environment is required.

Means for solving the problems

The present invention provides the following [1] to [16 ].

[1] An optical laminate comprising a polarizing plate, a1 st cured product layer, a phase difference layer and an adhesive layer in this order,

the polarizing plate is formed of a polyvinyl alcohol resin containing iodine,

the 1 st cured product layer is a cured product of an active energy curable composition,

the phase difference layer includes at least one phase difference developing layer of a polymer as a polymerizable liquid crystal compound,

the adhesive layer has an iodine content of 900mg/kg or less after the optical laminate is stored at 80 ℃ and a relative humidity of 90% for 250 hours,

the polarizing plate is in direct contact with the 1 st cured product layer,

the 1 st cured product layer is in direct contact with the retardation layer.

[2] The optical laminate according to [1], wherein the retardation layer is a layer comprising a1 st polymerization layer, a2 nd curing layer and a2 nd polymerization layer in this order from the 1 st curing layer side,

the 1 st polymerization layer and the 2 nd polymerization layer each independently contain a polymer of a polymerizable liquid crystal compound.

[3] The optical laminate according to [2], wherein the 2 nd cured layer is an active energy ray-cured layer.

[4]According to [1]～[3]The optical laminate according to any one of the above items, wherein the first cured product layer 1 has a moisture permeability at a temperature of 80 ℃ and a relative humidity of 90% of 1500[ g/(m) at a thickness of 30 μm ² ·24hr)]The following.

[5] An optical laminate comprising a polarizing plate, a1 st cured product layer, a1 st retardation layer, a2 nd cured product layer, a2 nd retardation layer and an adhesive layer in this order,

the polarizing plate is formed of a polyvinyl alcohol resin containing iodine,

the 1 st retardation layer and the 2 nd retardation layer each independently comprise a retardation-developing layer comprising a polymer of a polymerizable liquid crystal compound,

the 1 st cured product layer and the 2 nd cured product layer each independently contain a cured product of an active energy ray-curable composition,

the 1 st cured product layer has a storage modulus at a temperature of 80 ℃ of 300MPa or more,

the polarizing plate is in direct contact with the 1 st cured product layer,

the 1 st cured product layer is in direct contact with the 1 st retardation layer.

[6] The optical laminate according to [5], wherein the 2 nd cured product layer has a storage modulus of 20MPa or more at a temperature of 80 ℃.

[7]According to [5]]Or [6]]The optical laminate, wherein the 1 st cured product layer has a storage modulus (E) at a temperature of 80 ℃ ₁ ) Greater than the storage modulus (E) of the 2 nd cured product layer at a temperature of 80 DEG C ₂ )。

[8]According to [5]]～[7]The optical laminate according to any one of the above items, wherein the first cured product layer 1 has a moisture permeability at a temperature of 80 ℃ and a relative humidity of 90% of 1500[ g/(m) at a thickness of 30 μm ² ·24hr)]The following.

[9] An optical laminate comprising a polarizing plate, a1 st cured product layer, a1 st retardation layer, a2 nd assimilator layer, a2 nd retardation layer and a pressure-sensitive adhesive layer in this order,

the polarizing plate is formed of polyvinyl alcohol resin containing iodine,

the 1 st retardation layer and the 2 nd retardation layer each independently comprise a retardation developing layer of a polymer which is a polymerizable liquid crystal compound,

the 1 st cured product layer and the 2 nd cured product layer are each independently a cured product of an active energy ray-curable composition,

glass transition temperature (Tg) of the 1 st cured product layer ₁ ) More than 60 ℃ of the total weight of the composition,

the polarizing plate is in direct contact with the 1 st cured product layer,

[10]According to [9]]The optical laminate according to the above, wherein the 2 nd cured product layer has a glass transition temperature (Tg) ₂ ) Is above 40 ℃.

[11]According to [9]]Or [10 ]]The optical laminate according to the above, wherein the 1 st cured product layer has a glass transition temperature (Tg) ₁ ) Greater than the glass transition temperature (Tg) of the 2 nd cured product layer ₂ )。

[12]According to [9]]～[11]The optical laminate according to any one of the above items, wherein the first cured product layer 1 has a moisture permeability at a temperature of 80 ℃ and a relative humidity of 90% of 1500[ g/(m) at a thickness of 30 μm ² ·24hr)]The following.

[13] An optical laminate comprising a polarizing plate, a1 st cured product layer, a phase difference layer and an adhesive layer in this order,

the polarizing plate is formed of a polyvinyl alcohol resin containing iodine,

the phase difference layer comprises a phase difference-developing layer containing a polymer of a polymerizable liquid crystal compound,

the active energy ray-curable composition is a composition containing an epoxy compound (a2-1), wherein the epoxy compound (a2-1) contains A3-ring fused ring and 2 glycidyl ether groups in a molecule.

[14] An optical laminate comprising a polarizing plate, a1 st cured product layer, a1 st retardation layer, a2 nd cured product layer, a2 nd retardation layer and an adhesive layer in this order,

the polarizing plate is formed of a polyvinyl alcohol resin containing iodine,

[15] An active energy ray-curable composition comprising 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 A3-ring fused ring and a diglycidyl ether group in the molecule,

the content of the polyfunctional oxetane compound (A5-1) is larger than that of the epoxy compound (A2-1) having A3-ring fused ring and 2 glycidyl ether groups in the molecule.

[16] The active energy ray-curable composition according to [15], wherein a content ratio (mass ratio) of the polyfunctional oxetane compound (A5-1) to the epoxy compound (A2-1) having A3-ring fused ring and 2 glycidyl ether groups in a molecule is 1.5/1 to 5/1 per the polyfunctional oxetane compound (A5-1)/the epoxy compound (A2-1) having A3-ring fused ring and 2 glycidyl ether groups in a molecule.

Effects of the invention

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

Drawings

FIG. 1 is a schematic sectional view schematically showing a laminate of the present invention.

FIG. 2 is a schematic cross-sectional view schematically showing a retardation layer.

FIG. 3 is a schematic cross-sectional view schematically showing an example of each production step in the method for producing a laminate.

Detailed Description

Hereinafter, embodiments of the present invention will be described with reference to the drawings, but the present invention is not limited to the embodiments below. In all the drawings below, the components are illustrated with their scales adjusted as appropriate for easy understanding, and the scales of the components shown in the drawings do not necessarily coincide with the scales of the actual components.

< optical layered body >

The optical laminate of the present invention is explained with reference to fig. 1. The optical laminate 100 shown in fig. 1 includes a polarizing plate 13, a1 st cured product layer 14, a phase difference layer 20, and an adhesive layer 70 in this order, the polarizing plate 13 being in direct contact with the 1 st cured product layer 14, and the 1 st cured product layer 14 being in direct contact with the phase difference layer 20. The thermoplastic resin film 11 may be laminated on the side of the polarizing plate 13 opposite to the first cured product layer 14 via an adhesive layer 12. Further, the retardation layer 20 is preferably in direct contact with the adhesive layer 70. In the present invention, the linear polarizing plate 10 is referred to as a configuration including the thermoplastic resin film 11, the adhesive layer 12, and the polarizer 13 in this order.

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

The optical laminate 100 may be long or may be a single sheet. When the optical laminate 100 is a single sheet, the shape of the optical laminate 100 in a plan view may be substantially rectangular. The planar view is a view seen from the thickness direction of the optical laminate 100. By substantially rectangular it is meant that the following shapes are possible: a shape in which at least 1 corner portion out of 4 corners (corner portions) is cut out to form an obtuse angle or a shape provided with a circular arc; a part of the end surface in plan view has a recess (notch) recessed in the in-plane direction; or a perforated portion which is partially hollowed out in a shape in plan view to have a circular shape, an elliptical shape, a polygonal shape, a combination thereof, or the like.

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

(thermoplastic resin film)

The thermoplastic resin film 11 may be disposed on the viewing side of the laminate. The thermoplastic resin film 11 may have a function as a protective film for protecting the polarizing plate 13. Although not shown, the thermoplastic resin film may be disposed on both sides of the polarizing plate, but from the viewpoint of making the laminate thinner, the thermoplastic resin film is preferably disposed on one side of the polarizing plate, and more preferably disposed only on the viewing side of the laminate.

The material of the thermoplastic resin film 11 is not particularly limited, and examples thereof include films known in the art, such as a cyclic polyolefin resin film, an acetate resin film containing a resin such as triacetyl cellulose or diacetyl cellulose, a polyester resin film containing a resin such as polyethylene terephthalate, polyethylene naphthalate or polybutylene terephthalate, a polycarbonate resin film, a (meth) acrylic resin film, and a polypropylene resin film. 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, preferably 20 μm or more. The thermoplastic resin film 11 may or may not have a phase difference.

The thermoplastic resin film 11 may contain 1 or 2 or more kinds of additives such as rubber particles, lubricants, fluorescent brighteners, dispersants, heat stabilizers, light stabilizers, ultraviolet absorbers, infrared absorbers, antistatic agents, and antioxidants, as required. The thermoplastic resin film 11 preferably contains an ultraviolet absorber from the viewpoint of the durability (light resistance) of the laminate.

From the viewpoint of corrosion resistance, the moisture permeability of the thermoplastic resin film 11 is preferably 100g/m ² 24hr or less, more preferably 30g/m ² 24hr or less.

(adhesive layer)

The adhesive layer 12 is a layer formed of an adhesive for bonding the thermoplastic resin film 11 and the polarizing plate 13. The adhesive may exhibit adhesion to both of them, and examples thereof include an aqueous adhesive in which an adhesive component is dissolved or dispersed in water, and an active energy ray-curable adhesive composition containing an active energy ray-curable compound.

The water-based adhesive composition may be a composition containing a polyvinyl alcohol resin or a urethane resin as a main component and a crosslinking agent such as an isocyanate compound or an epoxy compound or a curable compound for improving adhesiveness.

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

In the aqueous adhesive composition comprising an aqueous solution of a polyvinyl alcohol resin, a curable compound such as a polyaldehyde, a water-soluble epoxy resin, a melamine compound, a zirconia compound, or a zinc compound may be added to improve the adhesiveness. Examples of water-soluble epoxy resins include: a water-soluble polyamide-epoxy resin is obtained by reacting a polyalkylene polyamine such as diethylenetriamine or triethylenetetramine with a dicarboxylic acid such as adipic acid to obtain a polyamide polyamine, and reacting epichlorohydrin with the polyamide polyamine. As a commercially available product of such a polyamide epoxy resin, there are: "Sumirez Resin 650" and "Sumirez Resin 675" sold by Sumirex corporation, and "WS-525" sold by Nippon PMC corporation, and the like. When the water-soluble epoxy resin is blended, the amount thereof to be added is usually 1 part by mass or more and 100 parts by mass or less, and preferably 1 part by mass or more and 50 parts by mass or less, based on 100 parts by mass of the polyvinyl alcohol resin.

In addition, when a urethane resin is used as a main component of the aqueous adhesive composition, it is effective to use a polyester ionomer urethane resin as a main component of the aqueous adhesive composition. The polyester ionomer urethane resin as used herein refers to a urethane resin having a polyester skeleton into which a small amount of ionic components (hydrophilic components) are introduced. The ionomer urethane resin is directly emulsified in water without using an emulsifier to form an emulsion, and thus can be used as an aqueous adhesive. When a polyester ionomer urethane resin is used, it is effective to incorporate a water-soluble epoxy compound as a crosslinking agent. Examples of methods for using a polyester ionomer urethane resin as an adhesive for a polarizing plate are disclosed in japanese patent laid-open nos. 2005-70140 and 2005-208456.

The aqueous adhesive composition may contain a filler, a flow regulator, an antifoaming agent, a leveling agent, a pigment, an organic solvent, and the like.

The aqueous adhesive composition is usually used in a form in which each component is dissolved in water. The water-insoluble component contained in the aqueous adhesive composition may be dispersed in the system. The transparent adhesive may be formed by applying the aqueous adhesive composition to one surface of the polarizing plate and drying the composition.

The aqueous adhesive composition is applied to one surface or both surfaces of a polarizing plate or a thermoplastic resin film, and after the application, the aqueous adhesive composition is heated to evaporate water and simultaneously to perform a thermal crosslinking reaction, thereby sufficiently bonding the polarizing plate or the thermoplastic resin film to each other. A laminate in which the polarizing plate 13 and the thermoplastic resin film 11 are laminated with the adhesive layer 12 interposed therebetween is also referred to as a linear polarizing plate 10.

As the active energy ray-curable adhesive composition, the following description of the 1 st cured product layer 14 can be applied. The active energy ray-curable adhesive composition used for the adhesive layer 12 may not contain any of a photosensitizer and a photosensitizing assistant. The type of the active energy ray-curable adhesive composition may be the same as or different from that of the active energy ray-curable adhesive composition contained in the 1 st cured layer 14.

The thickness of the 1 st 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 1 st adhesive layer 12 may be, for example, 0.1 μm or more.

(polarizing plate)

The polarizing plate 13 may be an absorption-type polarizing plate having a property of absorbing linearly polarized light having a vibration plane parallel to the absorption axis thereof and transmitting linearly polarized light having a vibration plane orthogonal to the absorption axis (parallel to the transmission axis). As the polarizing plate 13, a polarizing plate in which a dichroic dye is adsorbed and oriented on a uniaxially stretched polyvinyl alcohol resin film can be preferably used. The polarizing plate 13 can be manufactured, for example, by a method including the steps of: a step of uniaxially stretching a polyvinyl alcohol resin film; a step of dyeing a polyvinyl alcohol resin film with a dichroic dye to adsorb the dichroic dye; a step of treating the polyvinyl alcohol resin film having the dichroic dye adsorbed thereon with a crosslinking liquid such as an aqueous boric acid solution; and a step of washing with water after the treatment with the crosslinking liquid.

As the polyvinyl alcohol resin, a resin obtained by saponifying a polyvinyl acetate resin can be used. Examples of the polyvinyl acetate resin include polyvinyl acetate which is a homopolymer of vinyl acetate, and copolymers with other monomers copolymerizable with 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, and the like.

In the present specification, "(meth) acrylic acid" means at least one selected from acrylic acid and methacrylic acid. The same applies to "(meth) acryloyl group", "meth (acrylate)" and the like.

The saponification degree of the polyvinyl alcohol resin is usually 85 to 100 mol%, preferably 98 mol% or more. The polyvinyl alcohol resin may be modified, and for example, polyvinyl formal, polyvinyl acetal, or the like modified with aldehydes may be used. The polyvinyl alcohol resin has an average polymerization degree of usually 1000 to 10000, preferably 1500 to 5000. The average polymerization degree of the polyvinyl alcohol resin can be determined in accordance with JIS K6726.

The film obtained by forming such a polyvinyl alcohol resin into a film can be used as a raw material film for a polarizing plate. The method for forming the film from the polyvinyl alcohol resin is not particularly limited, and a known method can be used. The thickness of the polyvinyl alcohol-based raw material film is not particularly limited, and may be, for example, 5 μm or more and 85 μm or less.

The uniaxial stretching of the polyvinyl alcohol resin film may be performed before, simultaneously with, or after the dyeing of the dichroic dye. In the case where the uniaxial stretching is performed after dyeing, the uniaxial stretching may be performed before or during the crosslinking treatment. In addition, uniaxial stretching may be performed in these plural stages.

In the case of uniaxial stretching, the stretching may be performed uniaxially between rolls having different peripheral speeds, or may be performed uniaxially using a heat roll. The uniaxial stretching may be dry stretching in which stretching is performed in the air, or wet stretching in which stretching is performed in a state where the polyvinyl alcohol resin film is swollen with a solvent or water. The draw ratio is usually 3 to 8 times.

As a method for dyeing a polyvinyl alcohol resin film with a dichroic dye, for example, a method of immersing the film in an aqueous solution containing a dichroic dye can be used. Iodine or a dichroic organic dye may be used as the dichroic dye. The polyvinyl alcohol resin film is preferably subjected to an immersion treatment in water before the dyeing treatment.

As the crosslinking treatment after dyeing with the dichroic dye, a method of immersing the dyed polyvinyl alcohol resin film in an aqueous solution containing boric acid is generally employed. When iodine is used as the dichroic dye, the aqueous solution containing boric acid preferably contains potassium iodide.

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

(1 st cured product layer)

The 1 st cured product layer 14 is disposed between the polarizer 13 and the retardation layer 20 for bonding the polarizer 13 and the retardation layer 20 (for bonding a linear polarizer and a retardation laminate described later). The 1 st cured layer 14 is a cured product of an active energy ray-curable adhesive composition. By forming the 1 st cured layer 14 from a cured product of an active energy ray-curable adhesive composition, it is possible to suppress transfer of iodine contained in the polarizing plate and suppress corrosion of the conductive layer when laminated with the conductive layer, compared with the case of using an adhesive layer. In the present invention, the corrosiveness was evaluated according to the evaluation method described in the section of examples, which will be described later.

The thickness of the 1 st cured product layer 14 may be, for example, 10 μm or less, preferably 5 μm or less, more preferably 4m or less, and still more preferably 3 μm or less. The thickness of the 1 st 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 composition as long as it is cured by irradiation with an active energy ray, and may be, for example, a cationically polymerizable adhesive composition or a radically polymerizable adhesive composition. The active energy ray-curable adhesive composition is preferably a cationically polymerizable adhesive composition.

(cationic polymerizable adhesive composition)

The cationically polymerizable adhesive composition contains a curable component (A) and a photo cationic polymerization initiator (B). The curable component (a) is a component that can be cured by cationic polymerization by irradiation with active energy rays. The adhesive force is exhibited by polymerization and curing of the curable component (a).

(curable component (A))

The curable component (a) may contain at least one of the alicyclic epoxy compound (a1) and the polyfunctional aliphatic epoxy compound (a 2). The curable component (a) may further contain at least 1 selected from the group consisting of a monofunctional epoxy compound (A3), a polyfunctional aromatic epoxy compound (a4), and an oxetane compound (a 5).

When the curable component (a) contains the alicyclic epoxy compound (a1), the content of the alicyclic epoxy compound (a1) may be, for example, 5 parts by mass or more and 90 parts by mass or less, and preferably 10 parts by mass or more and 80 parts by mass or less, relative to 100 parts by mass of the curable component (a).

When the curable component (a) contains the polyfunctional aliphatic epoxy compound (a2), the content of the polyfunctional aliphatic epoxy compound (a2) may be, for example, 1 part by mass or more and 50 parts by mass or less, and preferably 5 parts by mass or more and 45 parts by mass or less, relative to 100 parts by mass of the curable component (a).

When the curable component (a) contains the monofunctional epoxy compound (A3), the content of the monofunctional epoxy compound (A3) may be, for example, 1 part by mass or more and 20 parts by mass or less, and preferably 1 part by mass or more and 15 parts by mass or less, relative to 100 parts by mass of the curable component (a).

When the curable component (a) contains the polyfunctional aromatic epoxy compound (a4), the content of the polyfunctional aromatic epoxy compound (a4) may be, for example, 1 part by mass or more and 60 parts by mass or less, and preferably 1 part by mass or more and 50 parts by mass or less, relative to 100 parts by mass of the curable component (a).

When the curable component (a) contains the oxetane compound (a5), the content of the oxetane compound (a5) may be, for example, 5 parts by mass or more and 90 parts by mass or less, and preferably 10 parts by mass or more and 80 parts by mass or less, relative to 100 parts by mass of the curable component (a).

The active energy ray-curable adhesive composition preferably contains no solvent. Hereinafter, each component will be described in detail.

(alicyclic epoxy Compound (A1))

The alicyclic epoxy compound (a1) is a compound having 1 or more alicyclic epoxy groups. The alicyclic epoxy compound (a1) may have 1 or more alicyclic epoxy groups, and may further have an epoxy group other than an alicyclic epoxy group. In the present specification, an alicyclic epoxy group means an epoxy group bonded to an alicyclic ring, and means a bridged oxygen atom-O-in the structure represented by the following formula (a).

[ chemical formula 1]

In the formula (a), m is an integer of 2 to 5. Removal of the above formula (a) (CH) ₂ ) _m The compound in which 1 or more hydrogen atoms in the compound are bonded to other chemical structures may be an alicyclic epoxy compound (a 1). (CH) ₂ ) _m 1 or more hydrogen atoms in (b) may be appropriately substituted with a linear alkyl group such as a methyl group or an ethyl group. The curing speed of the active energy ray-curable adhesive composition can be adjusted by the alicyclic epoxy compound (a 1).

Specific examples of the alicyclic epoxy compound (A1) include 3, 4-epoxycyclohexylmethyl 3, 4-epoxycyclohexanecarboxylate, 1, 2-epoxy-4-vinylcyclohexane, 1, 2-epoxy-1-methyl-4- (1-methylepoxyethyl) cyclohexane, 3, 4-epoxycyclohexylmethyl methacrylate, 4- (1, 2-epoxyethyl) -1, 2-epoxycyclohexane adduct of 2, 2-bis (hydroxymethyl) -1-butanol, ethylenebis (3, 4-epoxycyclohexanecarboxylate), oxydiethylenebis (3, 4-epoxycyclohexanecarboxylate), 1, 4-cyclohexanedimethylbis (3, 4-epoxycyclohexanecarboxylate), And 3- (3, 4-epoxycyclohexylmethoxycarbonyl) 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 an appropriate curability and can be obtained at a relatively low cost. As the alicyclic epoxy compound (a1), 1 kind of alicyclic epoxy compound may be used alone, or a plurality of different alicyclic epoxy compounds may be used in combination.

As the alicyclic epoxy compound (A1), commercially available products can be used, and for example, the "Celoxide (registered trademark)" series and the "Cyclomer (registered trademark)" series sold by DAICEL, manufactured by Kabushiki Kaisha, and the "Cyracure UVR" series sold by DOW Chemical company are shown by trade names, respectively.

(polyfunctional aliphatic epoxy Compound (A2))

The polyfunctional aliphatic epoxy compound (a2) has 2 or more epoxy groups and has no aromatic ring. However, the polyfunctional aliphatic epoxy compound (a2) referred to in the present specification does not include a compound having an alicyclic epoxy group, which is contained in the alicyclic epoxy compound (a 1). The adhesion of the cured adhesive layer can be adjusted by the polyfunctional aliphatic epoxy compound (a 2).

The polyfunctional aliphatic epoxy compound (a2) is more preferably an aliphatic diepoxy compound represented by the following formula (b). By containing an aliphatic diepoxy compound represented by the following formula (b) as the polyfunctional aliphatic epoxy compound (a2), an active energy ray-curable adhesive agent having low viscosity and being easy to apply can be obtained.

[ chemical formula 2]

In the formula (b), Z is an alkylene group having 1 to 9 carbon atoms, an alkylidene group having 3 or 4 carbon atoms, a 2-valent alicyclic hydrocarbon group, or a group represented by the formula-C _m H _2m -Z ¹ -C _n H _2n -a 2-valent radical as indicated. In addition, the above formula-C _m H _2m -Z ¹ -C _n H _2n -in, -Z ¹ -is-O-, -CO-O-, -O-CO-, -SO ₂ -, -SO-or CO-, m and n each independently represent an integer of 1 or more, and the total of m and n is 9 or less.

The alicyclic hydrocarbon group having a valence of 2 is, for example, a 2-valent alicyclic hydrocarbon group having 4 to 16 carbon atoms, and examples thereof include a 2-valent group represented by the following formula (b-1) and a 2-valent group represented by the following formula (b-2).

[ chemical formula 3]

[ chemical formula 4]

Specific examples of the compound represented by the formula (b) include diglycidyl ethers of alkylene glycols, diglycidyl ethers of oligo alkylene glycols having a repetition number of up to about 4, diglycidyl ethers of alicyclic glycols, and the like.

Examples of the diol (diol) capable of forming the compound represented by the formula (b) include ethylene glycol, propylene glycol, 1, 3-propanediol, 2-methyl-1, 3-propanediol, 2-butyl-2-ethyl-1, 3-propanediol, 1, 4-butanediol, neopentyl glycol, 3-methyl-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-heptanediol, 1, 8-octanediol, 2-methyl-1, alkanediols such as 8-octanediol and 1, 9-nonanediol; oligo alkylene glycols such as diethylene glycol, triethylene glycol, tetraethylene glycol, and dipropylene glycol; alicyclic diols such as cyclohexanediol, cyclohexanedimethanol, dicyclopentadiene dimethanol and the like.

In the present invention, 1, 4-butanediol diglycidyl ether, 1, 6-hexanediol diglycidyl ether, neopentyl glycol diglycidyl ether, and dicyclopentadiene methanol diglycidyl ether are preferable as the polyfunctional aliphatic epoxy compound (a2) in terms of obtaining an active energy ray-curable adhesive composition having a low viscosity and easy application.

As the polyfunctional aliphatic epoxy compound (a2), 1 kind of aliphatic epoxy compound may be used alone, or a plurality of different kinds may be used in combination.

In addition, as an embodiment of the present invention, the polyfunctional aliphatic epoxy compound (a2) is preferably an epoxy compound (a2-1) containing A3-ring fused ring and 2 glycidyl ether groups in the molecule.

The 3-ring fused ring is not particularly limited as long as it is a fused ring composed of 3 rings, and is preferably a fused ring composed of an aliphatic ring. Examples of the 3-ring fused ring include an adamantane ring, tricyclodecane ring, dicyclopentadiene ring, and tricyclodecene ring.

Examples of the epoxy compound (A2-1) having a 3-ring fused ring and 2 glycidyl ether groups in the molecule include compounds represented by the following formula (c-1).

[ chemical formula 5]

[ in the formula (c-1), X ₁ Represents a condensed ring of 3 ring type, Z ² And Z ³ Each independently represents a single bond or a 2-valent hydrocarbon group.]

X ₁ Examples of the fused ring having a 3-ring structure include an adamantane ring, tricyclodecane ring, dicyclopentadiene ring, and tricyclodecene ring, and a tricyclodecane ring is preferable.

As Z ² And Z ³ Examples of the 2-valent hydrocarbon group include alkanediyl groups having 1 to 8 carbon atoms such as methylene, ethylene and propylene glycol groups; an aromatic hydrocarbon group having 6 to 10 carbon atoms such as phenylene group.

Preferably Z ² And Z ³ Each independently a 2-valent hydrocarbon group, more preferably an alkanediyl group having 1 to 8 carbon atoms, still more preferably an alkanediyl group having 1 to 4 carbon atoms, and particularly preferably a methylene group.

As the polyfunctional aliphatic epoxy compound (A2), commercially available products can be used, and examples thereof include "EP-4088S" (manufactured by ADEKA K.K.), "EHPE 3150" (manufactured by Daicel K.K.), "EX-211L" and "EX-212L" (manufactured by Nagase ChemteX K.K.).

(monofunctional epoxy Compound (A3))

The monofunctional epoxy compound (a3) is a compound having 1 epoxy group. The monofunctional epoxy compound (A3) mentioned in the present specification does not include a compound having an alicyclic epoxy group in the molecule contained in the alicyclic epoxy compound (A1). The monofunctional epoxy compound (a3) may have an aromatic ring in the molecule or may not have an aromatic ring. The viscosity of the active energy ray-curable adhesive composition can be adjusted by the monofunctional epoxy compound (a 3).

Examples of the monofunctional epoxy compound having an aromatic ring (a3) include monoglycidyl etherate of a monohydric phenol such as phenol, cresol, or butylphenol, or a bisphenol derivative such as bisphenol a or bisphenol F, or an alkylene oxide adduct thereof; epoxy phenolic resin; monoglycidyl etherate of an aromatic compound having 2 or more phenolic hydroxyl groups such as resorcinol, hydroquinone, catechol, or the like; monoglycidyl etherate of aromatic compound having 2 or more alcoholic hydroxyl groups such as benzenedimethanol, benzenediethanol, and benzenedibutanol; monoglycidyl esters of polybasic acid aromatic compounds having 2 or more carboxyl groups, such as phthalic acid, terephthalic acid, and trimellitic acid; glycidyl esters of benzoic acid, toluic acid, monoglycidyl esters of naphthoic acid, and the like.

Examples of the monofunctional epoxy compound (A3) having no aromatic ring include glycidyl etherate of aliphatic alcohol, glycidyl ester of alkyl carboxylic acid, and the like, and specific examples thereof include allyl glycidyl ether, butyl glycidyl ether, sec-butyl phenyl glycidyl ether, 2-ethylhexyl glycidyl ether, mixed alkyl glycidyl ethers having 12 and 13 carbon atoms, glycidyl ethers of alcohol, monoglycidyl ethers of aliphatic higher alcohols, glycidyl esters of higher fatty acids, and the like. As the monofunctional epoxy compound (a3), 1 type of monofunctional epoxy compound may be used alone, or a plurality of different types may be used in combination.

As the monofunctional epoxy compound (A3), commercially available compounds can be used, and examples thereof include "EX-142", "EX-146", EX-147 "and" EX-121 "(all of which are manufactured by Nagase ChemteX Co., Ltd.).

(polyfunctional aromatic epoxy Compound (A4))

The polyfunctional aromatic epoxy compound (a4) is a compound having 2 or more epoxy groups and an aromatic ring. The polyfunctional aromatic epoxy compound (a4) referred to in the present specification does not include a compound having an alicyclic epoxy group in the molecule, which is contained in the alicyclic epoxy compound (a 1).

Specific examples of the polyfunctional aromatic epoxy compound (a4) include polyglycidyl etherate of naphthalene or a naphthalene derivative (also referred to as "naphthalene-type epoxy compound"); polyglycidyl etherates of bisphenol derivatives such as bisphenol a and bisphenol F (also referred to as "bisphenol a-type epoxy compounds" and "bisphenol F-type epoxy compounds"); epoxy phenolic resin; polyglycidyl etherates of aromatic compounds having 2 or more phenolic hydroxyl groups, such as resorcinol, hydroquinone, and catechol; polyglycidyl ether compounds of aromatic compounds having 2 or more alcoholic hydroxyl groups such as benzenedimethanol, benzenediethanol, and benzenedibutanol; polyglycidyl esters of polybasic acid aromatic compounds having 2 or more carboxyl groups, such as phthalic acid, terephthalic acid, and trimellitic acid; glycidyl esters of benzoic acid, polyglycidyl esters of toluic acid, naphthoic acid, and the like; and a diepoxide of a phenyl oxirane such as phenyl oxirane, alkylated phenyl oxirane, or vinyl naphthalene, or divinylbenzene. As the polyfunctional aromatic epoxy compound (a4), 1 kind of compound may be used alone, or a plurality of different kinds may be used in combination.

As the polyfunctional aromatic epoxy compound (A4), commercially available products can be used, and examples thereof include "DENACOL EX-201", "DENACOL EX-711" and "DENACOL EX-721" (all of which are manufactured by Nagase ChemteX); "OGSOL EG-280" and "OGSOL CG-400" (both of which are manufactured by Osaka Gas Chemical Co., Ltd.); "EXA-80 CRP" and "HP 4032D" (both of which are available from DIC corporation); "jER 828" and "jER 828 EL" (both of which are manufactured by Mitsubishi chemical corporation); "ADEKA RESIN EP-4100", "ADEKA RESIN EP-4100G", "ADEKA RESIN EP-4100E", "ADEKARESIN EP-4100L", "ADEKA RESIN EP-4100 TX", "ADEKA RESIN EP-4000", "ADEKA RESIN EP-4005", "ADEKA RESIN EP-4901" and "ADEKA RESIN EP-4901E" (all of which are manufactured by ADEKA Co., Ltd.).

(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. The oxetane compound (a5) enables adjustment of the curing speed and viscosity of the active energy ray-curable adhesive composition, and also enables improvement of the reactivity.

The oxetane compound (A5) may be a monofunctional oxetane compound having 1 oxetanyl group or a polyfunctional oxetane compound having 2 or more oxetanyl groups (A5-1). The oxetane compound (A5) is preferably a polyfunctional oxetane compound (A5-1), more preferably a 2-functional oxetane compound.

Specific examples of the oxetane compound (A5) include 3, 7-bis (3-oxetanyl) -5-oxa-nonane, 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, and mixtures thereof, 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-ethyloxetan-3-yl) methoxy ] methyl } oxetane, xylylene dioxirane, etc. As the oxetane compound (a5), 1 kind of oxetane compound may be used alone, or a plurality of different kinds may be used in combination.

The Oxetane compound (A5) can be used as a commercially available product, and examples thereof include "Aron Oxetane (registered trademark)" series sold by Tokyo synthetic Co., Ltd, and "ETERNACOLL (registered trademark)" series sold by Utsu Kyowa K.K., respectively, as indicated by the trade name.

In order to make the active energy ray-curable adhesive composition solvent-free, it is preferable to use the curable components [ alicyclic epoxy compound (a1), polyfunctional aliphatic epoxy compound (a2), monofunctional epoxy compound (A3), polyfunctional aromatic epoxy compound (a4), oxetane compound (a5) ] without diluting with an organic solvent or the like.

The curable component is usually selected from those which are liquid at room temperature, have appropriate fluidity even in the absence of a solvent, and impart appropriate adhesive strength, and an active energy ray-curable adhesive composition containing a photo cation polymerization initiator suitable for the selected curable component can be used in an optical laminate production facility, and a drying facility for evaporating the solvent in the step of bonding the linear polarizing plate and the retardation layer laminate can be omitted. Further, by irradiating the resin with an appropriate amount of active energy rays, the curing rate can be accelerated, and the production rate can be increased.

(other curable Components)

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

(radically polymerizable curable component)

The radical polymerizable compound is a compound or oligomer which is cured by radical polymerization reaction by irradiation with active energy rays such as ultraviolet rays, visible light, electron beams, and X-rays and heating, and specifically, a compound having an ethylenically unsaturated bond is exemplified. Examples of the compound having an ethylenically unsaturated bond include, in addition to a (meth) acrylic compound having 1 or more (meth) acryloyl groups in the molecule, a vinyl compound such as styrene, styrene sulfonic acid, vinyl acetate, vinyl propionate, and N-vinyl-2-pyrrolidone. Among them, the radical polymerizable compound is preferably a (meth) acrylic compound.

Examples of the (meth) acrylic compound include (meth) acryloyl group-containing compounds such as (meth) acrylic oligomers having at least 2 (meth) acryloyl groups in the molecule obtained by reacting 2 or more types of (meth) acrylate monomers having at least 1 (meth) acryloyloxy group in the molecule, and (meth) acrylamide monomers and functional group-containing compounds. The (meth) acrylic acid oligomer is preferably a (meth) acrylate oligomer having at least 2 (meth) acryloyloxy groups in the molecule. The (meth) acrylic compound may be used alone in 1 kind, or may be used in combination in 2 or more kinds.

Examples of the (meth) acrylate monomer include a monofunctional (meth) acrylate monomer having 1 (meth) acryloyloxy group in the molecule, a 2-functional (meth) acrylate monomer having 2 (meth) acryloyloxy groups in the molecule, and a polyfunctional (meth) acrylate monomer having 3 or more (meth) acryloyloxy groups in the molecule.

As an example of the monofunctional (meth) acrylate monomer, there is alkyl (meth) acrylate. In the alkyl (meth) acrylate, when the number of carbon atoms of the alkyl group is 3 or more, the alkyl group may be linear or branched. Specific examples of the alkyl (meth) acrylate include methyl (meth) acrylate, ethyl (meth) acrylate, isopropyl (meth) acrylate, butyl (meth) acrylate, isobutyl (meth) acrylate, t-butyl (meth) acrylate, and 2-ethylhexyl (meth) acrylate. In addition, aralkyl (meth) acrylates such as benzyl (meth) acrylate; (meth) acrylic acid esters of terpene alcohols such as isobornyl (meth) acrylate; (meth) acrylates having a tetrahydrofurfuryl structure such as tetrahydrofurfuryl (meth) acrylate; (meth) acrylates having a cycloalkyl group at the alkyl moiety, such as cyclohexyl (meth) acrylate, cyclohexylmethyl methacrylate, dicyclopentyl acrylate, dicyclopentenyl (meth) acrylate, and 1, 4-cyclohexanedimethanol monoacrylate; aminoalkyl (meth) acrylates such as N, N-dimethylaminoethyl (meth) acrylate; (meth) acrylate having an ether bond at an alkyl position, such as 2-phenoxyethyl (meth) acrylate, dicyclopentenyloxyethyl (meth) acrylate, ethylcarbitol (meth) acrylate, and phenoxypolyethylene glycol (meth) acrylate, is used as a monofunctional (meth) acrylate monomer.

Furthermore, a monofunctional (meth) acrylate having a hydroxyl group at an alkyl portion and a monofunctional (meth) acrylate having a carboxyl group at an alkyl portion may be used. Specific examples of the monofunctional (meth) acrylate having a hydroxyl group at the alkyl position include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate or 3-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 2-hydroxy-3-phenoxypropyl (meth) acrylate, trimethylolpropane mono (meth) acrylate, pentaerythritol mono (meth) acrylate. Specific examples of the monofunctional (meth) acrylate having a carboxyl group at an alkyl site include 2-carboxyethyl (meth) acrylate, ω -carboxy-polycaprolactone (N ≈ 2) mono (meth) acrylate, 1- [2- (meth) acryloyloxyethyl ] phthalic acid, 1- [2- (meth) acryloyloxyethyl ] hexahydrophthalic acid, 1- [2- (meth) acryloyloxyethyl ] succinic acid, 4- [2- (meth) acryloyloxyethyl ] 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 may form a ring together with the nitrogen atom of (meth) acrylamide, and the ring may have an oxygen atom as a ring-forming atom in addition to a carbon atom and the nitrogen atom of (meth) acrylamide. Further, a substituent such as an alkyl group or an oxo group (═ O) may be bonded to a carbon atom constituting the ring.

Specific examples of the N-substituted (meth) acrylamide include N-alkyl (meth) acrylamides such as N-methyl (meth) acrylamide, N-ethyl (meth) acrylamide, N-isopropyl (meth) acrylamide, N-N-butyl (meth) acrylamide, N-t-butyl (meth) acrylamide, and N-hexyl (meth) acrylamide; n, N-dialkyl (meth) acrylamides such as N, N-dimethyl (meth) acrylamide, N-diethyl (meth) acrylamide and the like. The N-substituent may be an alkyl group having a hydroxyl group, and examples thereof include N-hydroxymethyl (meth) acrylamide, N- (2-hydroxyethyl) (meth) acrylamide, N- (2-hydroxypropyl) (meth) acrylamide and the like. Specific examples of the N-substituted (meth) acrylamide forming the 5-or 6-membered ring include N-acryloylpyrrolidine, 3-acryloyl-2-oxazolidinone, 4-acryloylmorpholine, N-acryloylpiperidine, and N-methacryloylpiperidine.

Examples of the 2-functional (meth) acrylate monomer include alkylene glycol di (meth) acrylate, polyoxyalkylene glycol di (meth) acrylate, halogen-substituted alkylene glycol di (meth) acrylate, di (meth) acrylate of aliphatic polyhydric alcohol, di (meth) acrylate of hydrogenated dicyclopentadiene or tricyclodecanedialkanol, di (meth) acrylate of dioxane glycol or dioxane dialkanol, di (meth) acrylate of alkylene oxide adduct of bisphenol a or bisphenol F, and epoxy di (meth) acrylate of bisphenol a or bisphenol F.

More specific examples of the 2-functional (meth) acrylate monomer include ethylene glycol di (meth) acrylate, 1, 3-butanediol di (meth) acrylate, 1, 4-butanediol di (meth) acrylate, 1, 6-hexanediol di (meth) acrylate, 1, 9-nonanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, trimethylolpropane di (meth) acrylate, pentaerythritol di (meth) acrylate, ditrimethylolpropane di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, dipropylene glycol di (meth) acrylate, tripropylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, and mixtures thereof, Polytetramethylene glycol di (meth) acrylate, silicone di (meth) acrylate, di (meth) acrylate of neopentyl glycol hydroxypivalate, 2-bis [4- (meth) acryloyloxyethoxyethoxyphenyl ] propane, 2-bis [4- (meth) acryloyloxyethoxyethoxyethoxyethoxyethoxycyclohexyl ] propane, hydrogenated dicyclopentadienyl di (meth) acrylate, tricyclodecane dimethanol di (meth) acrylate, 1, 3-dioxane-2, 5-diyl di (meth) acrylate [ alternative names: acetal compound of dioxane diol di (meth) acrylate ], hydroxypivalaldehyde and trimethylolpropane [ chemical name: di (meth) acrylate, tris (hydroxyethyl) isocyanurate di (meth) acrylate, and the like of 2- (2-hydroxy-1, 1-dimethylethyl) -5-ethyl-5-hydroxymethyl-1, 3-dioxane ].

Typical examples of the 3 or more functional polyfunctional (meth) acrylate monomer include 3 or more functional poly (meth) acrylates of aliphatic polyols such as glycerol tri (meth) acrylate, alkoxylated glycerol tri (meth) acrylate, trimethylolpropane tri (meth) acrylate, ditrimethylolpropane tetra (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, and dipentaerythritol hexa (meth) acrylate, and further include 3 or more functional poly (meth) acrylates of halogen-substituted polyols, tri (meth) acrylates of alkylene oxide adducts of glycerol, tri (meth) acrylates of alkylene oxide adducts of trimethylolpropane, and mixtures thereof, 1, 1, 1-tris [ (meth) acryloyloxyethoxyethoxy ] propane, tris (hydroxyethyl) isocyanurate tri (meth) acrylate, and the like.

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

The urethane (meth) acrylic oligomer refers to a compound having an urethane bond (-NHCOO-) and at least 2 (meth) acryloyl groups in a molecule. Specifically, a urethane reaction product of a hydroxyl group-containing (meth) acrylic monomer having at least 1 (meth) acryloyl group and at least 1 hydroxyl group in the molecule and a polyisocyanate, a urethane reaction product of a terminal isocyanate group-containing urethane compound obtained by reacting a polyol and a polyisocyanate, and a (meth) acrylic monomer having at least 1 (meth) acryloyl group and at least 1 hydroxyl group in the molecule, respectively, may be used.

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

Examples of the polyisocyanate to be used in the urethanization reaction with the hydroxyl group-containing (meth) acrylic monomer include hexamethylene diisocyanate, lysine diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, toluene diisocyanate, xylylene diisocyanate, diisocyanates obtained by hydrogenating aromatic isocyanates among these diisocyanates (for example, hydrogenated toluene diisocyanate, hydrogenated xylylene diisocyanate, and the like), diisocyanates or triisocyanates such as triphenylmethane triisocyanate and dibenzylbenzene triisocyanate, and polyisocyanates obtained by polymerizing the above diisocyanates.

As the polyol for producing the isocyanate group-terminated urethane compound by the reaction with the polyisocyanate, a polyester polyol, a polyether polyol or the like can be used in addition to the aromatic, aliphatic or alicyclic polyol. Examples of the aliphatic and alicyclic polyhydric alcohols include 1, 4-butanediol, 1, 6-hexanediol, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, neopentyl glycol, trimethylolethane, trimethylolpropane, ditrimethylolpropane, pentaerythritol, dipentaerythritol, dimethylolheptane, dimethylolpropionic acid, dimethylolbutyric acid, glycerin, hydrogenated bisphenol a, and the like.

The polyester polyol is obtained by a dehydration condensation reaction of the above polyol with a polycarboxylic acid or an anhydride thereof. Examples of the polycarboxylic acid or anhydride thereof include succinic acid (anhydride), adipic acid, maleic acid (anhydride), itaconic acid (anhydride), trimellitic acid (anhydride), pyromellitic acid (anhydride), phthalic acid (anhydride), isophthalic acid, terephthalic acid, hexahydrophthalic acid (anhydride), and the like, when the substance which may be an anhydride is denoted by "(anhydride)".

The polyether polyol may be, in addition to the polyalkylene glycol, a polyoxyalkylene-modified polyol obtained by the reaction of the above polyol or dihydroxybenzene with an alkylene oxide, or the like.

The polyester (meth) acrylic oligomer refers to a compound having an ester bond and at least 2 (meth) acryloyl groups (typically, (meth) acryloyloxy groups) in the molecule. Specifically, the water-soluble polymer can be obtained by a dehydration condensation reaction using (meth) acrylic acid, a polycarboxylic acid or an anhydride thereof, and a polyol. Examples of the polycarboxylic acid or anhydride thereof used in the dehydration condensation reaction include succinic acid (anhydride), adipic acid, maleic acid (anhydride), itaconic acid (anhydride), trimellitic acid (anhydride), pyromellitic acid (anhydride), hexahydrophthalic acid (anhydride), phthalic acid (anhydride), isophthalic acid, and terephthalic acid, when the substance which can be an anhydride is denoted by "(anhydride)". Examples of the polyhydric alcohol used in the dehydration condensation reaction include 1, 4-butanediol, 1, 6-hexanediol, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, neopentyl glycol, trimethylolethane, trimethylolpropane, ditrimethylolpropane, pentaerythritol, dipentaerythritol, dimethylolheptane, dimethylolpropionic acid, dimethylolbutyric acid, glycerin, hydrogenated bisphenol a, and the like.

The epoxy (meth) acrylic oligomer is obtained, for example, by addition reaction of a polyglycidyl ether and (meth) acrylic acid, and has at least 2 (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 the photo radical polymerization initiator include acetophenone-based initiators such as acetophenone, 3-methylacetophenone, benzildimethylketal, 1- (4-isopropylphenyl) -2-hydroxy-2-methylpropan-1-one, 2-methyl-1- [4- (methylthio) phenyl-2-morpholinopropan-1-one, and 2-hydroxy-2-methyl-1-phenylpropan-1-one; benzophenone-based initiators such as benzophenone, 4-chlorobenzophenone and 4, 4' -diaminobenzophenone; benzoin ether initiators such as benzoin propyl ether and benzoin ethyl ether; thioxanthone initiators such as 4-isopropylthioxanthone; further, xanthone, fluorenone, camphorquinone, benzaldehyde, anthraquinone are included.

The amount of the photo radical polymerization initiator is usually 0.5 parts by mass or more and 20 parts by mass or less, and preferably 1 part by mass or more and 6 parts by mass or less, per 100 parts by mass of the radical polymerizable compound. By blending not less than 0.5 parts by mass of the photo radical polymerization initiator, the radical polymerizable compound can be sufficiently cured, and the polarizing plate obtained can be provided with high mechanical strength and adhesive strength. On the other hand, if the amount is too large, the durability of the polarizing plate may be reduced.

Among them, since radical polymerization tends to cause large curing shrinkage, the active energy ray-curable adhesive composition preferably contains only a cationically polymerizable curable component as the curable component (a).

(photo cation polymerization initiator (B))

The active energy ray-curable adhesive composition contains a photo cation polymerization initiator (B). In this way, the curable component (a) can be cured by cationic polymerization by irradiation with an active energy ray to form an adhesive layer. The photo cation polymerization initiator (B) generates a cation species or lewis acid by irradiation of active energy rays such as visible rays, ultraviolet rays, X-rays, and electron beams, and initiates the polymerization reaction of the curable component (a). The photo cation polymerization initiator (B) functions as a catalyst by light, and therefore, even when it is mixed in the curable component (a), it is excellent in storage stability and handling properties. Examples of the compound which can be used as the photo cation polymerization initiator (B) and generates a cationic species or a lewis acid by irradiation with an active energy ray include aromatic diazonium salts; onium salts such as aromatic iodonium salts and aromatic sulfonium salts; iron-arene complexes, and the like.

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

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

Examples of the aromatic sulfonium salt include triphenylsulfonium hexafluorophosphate, triphenylsulfonium hexafluoroantimonate, triphenylsulfonium tetrakis (pentafluorophenyl) borate, 4 '-bis (diphenylsulfonium) -diphenylsulfide bis-hexafluorophosphate, 4' -bis (di (. beta. -hydroxyethoxy) phenylsulfonyl) diphenylsulfide bis-hexafluoroantimonate, 4 '-bis (di (. beta. -hydroxyethoxy) phenylsulfonyl) diphenylsulfide bis-hexafluoroantimonate, 7- [ di (p-toluoyl) sulfonium ] -2-isopropylthioxanthone tetrakis (pentafluorophenyl) borate, 4-phenylcarbonyl-4' -diphenylsulfonium-diphenylsulfide hexafluorophosphate, and mixtures thereof, 4- (p-tert-butylphenylcarbonyl) -4 '-diphenylsulfonium-diphenylsulfide hexafluoroantimonate, 4- (p-tert-butylphenylcarbonyl) -4' -di (p-toluoyl) sulfonium-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 (trifluoromethanesulfonyl) methanate.

The cationic photopolymerization initiator (B) may be used alone in 1 kind, or may be used in combination in 2 or more kinds. Among the above, aromatic sulfonium salts are particularly preferably used because they have ultraviolet absorption characteristics even in the wavelength region around 300nm and can give an adhesive cured layer excellent in curability and having good mechanical strength and adhesive strength.

The content of the photo cation 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 or less, relative to 100 parts by mass of the total amount of the curable components (a). By containing the photo cation polymerization initiator (B) in an amount of 1 part by mass or more, 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 increased, the ionic substance in the cured product increases, the hygroscopicity of the cured product increases, and the durability of the laminate may decrease, so that the amount of the photo cation polymerization initiator (B) is 10 parts by mass or less with respect to 100 parts by mass of the total amount of the curable components (a).

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

(photosensitizer (C))

The active energy ray-curable adhesive composition may contain a photosensitizer (C). By adding the photosensitizer (C) to the 1 st active energy ray-curable composition, the curability of the adhesive can be improved as compared with the case where the photosensitizer (C) is not contained.

The photosensitizer (C) contains an anthracene compound represented by the following general formula (I).

[ chemical formula 6]

(in the formula, R ¹ And R ² Independently represent an alkyl group having 1 to 6 carbon atoms or an alkoxyalkyl group having 2 to 12 carbon atoms, R ³ Represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms. )

The photo cation polymerization initiator (B) exhibits maximum absorption in a wavelength region around 300nm or shorter, and induces light of a wavelength around the photo cation polymerization initiator to generate a cation species or lewis acid to initiate cation polymerization of the cationically polymerizable curable component, but the photosensitizer (C) preferably exhibits maximum absorption in a wavelength region longer than 380nm in order to also induce light of a wavelength longer than the photo cation polymerization initiator. As the photosensitizer (C), an anthracene compound is suitably used.

Specific examples of the anthracene compound include:

9, 10-dimethoxy anthracene,

9, 10-diethoxyanthracene,

9, 10-dipropoxyanthracene,

9, 10-diisopropoxylanthracene,

9, 10-dibutoxyanthracene,

9, 10-dipentyloxy anthracene,

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-diisopropoxylanthracene,

2-methyl or 2-ethyl-9, 10-dibutoxyanthracene,

2-methyl or 2-ethyl-9, 10-dipentyloxy anthracene,

2-methyl or 2-ethyl-9, 10-diethyloxyanthracene.

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 the photosensitizer (C) is not included. Such an effect can be exhibited by setting the content of the photosensitizer to 0.1 parts by mass or more per 100 parts by mass of the total amount of the curable components (a). On the other hand, if the content of the photosensitizer (C) is increased, problems such as precipitation occur during low-temperature storage, and therefore, the content is preferably 2 parts by mass or less with respect to 100 parts by mass of the total amount of the curable components (a).

(photosensitive auxiliary (D))

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

Specific examples of the naphthalene-based photosensitizing assistant include:

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-dipropoxy naphthalene,

1, 4-dibutoxynaphthalene.

By incorporating a naphthalene-based photo-sensitive auxiliary in the active energy ray-curable adhesive composition, the curability of the adhesive can be improved as compared with the case where the naphthalene-based photo-sensitive auxiliary is not incorporated. Such an effect can be exhibited by setting the content of the naphthalene-based photosensitizing assistant to 0.1 part by mass or more relative to 100 parts by mass of the total amount of the curable components (a). On the other hand, if the content of the naphthalene-based photosensitizing assistant is increased, problems such as precipitation occur during low-temperature storage, and therefore, the content is preferably 5 parts by mass or less with respect to 100 parts by mass of the total amount of the curable components (a). The content of the naphthalene-based photosensitizing assistant is preferably 3 parts by mass or less with respect to 100 parts by mass of the total amount of the curable components (a).

(additive component (E))

The active energy ray-curable adhesive composition may contain the additive component (E) as another component belonging to the optional components as long as the effects of the present invention are not impaired. Examples of the additive component (E) include an ion scavenger, an antioxidant, a light stabilizer, a chain transfer agent, a thickener, a thermoplastic resin, a filler, a flow control agent, a plasticizer, a defoaming agent, a leveling agent, a coloring matter, an organic solvent, and the like.

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 components (a).

The photo cation polymerization initiator (B), the photosensitizer (C), the photosensitizing assistant (D), and the additive component (E) may be added in a state of not containing a solvent or may be added as it is after being diluted in a solvent, when the active energy ray-curable adhesive composition is prepared. The numerical ranges of the above contents are all numerical ranges on a solid content basis.

In one embodiment of the present invention, the active energy ray-curable composition forming the 1 st cured product layer is preferably a composition containing an epoxy compound (a2-1) containing A3-ring fused ring and 2 glycidyl ether groups in a molecule.

When the active energy ray-curable composition contains an epoxy compound (a2-1) containing A3-ring fused ring and 2 glycidyl ether groups in the molecule, it preferably further contains an oxetane compound (a5), more preferably contains a polyfunctional oxetane compound (a5-1), and still more preferably contains a 2-functional oxetane compound.

When the active energy ray-curable composition contains the epoxy compound (a2-1) containing A3-ring fused ring and 2 glycidyl ether groups in the molecule and the oxetane compound (a5), it is preferable that at least 1 selected from the group consisting of the alicyclic epoxy compound (a1) and the polyfunctional aliphatic epoxy compound (a2) is further contained (except the epoxy compound (a2-1) containing A3-ring fused ring and 2 glycidyl ether groups in the molecule).

When the active energy ray-curable composition contains the epoxy compound (a2-1) containing 3 ring-type condensed rings and 2 glycidyl ether groups in the molecule and the oxetane compound (a5), the content of the oxetane compound (a5) is larger than the content of the epoxy compound (a2-1) containing 3 ring-type condensed rings and 2 glycidyl ether groups in the molecule. When the active energy ray-curable composition contains the epoxy compound (A2-1) having 3 ring-type condensed rings and 2 glycidyl ether groups in the molecule and the polyfunctional oxetane compound (A5-1), the content of the polyfunctional oxetane compound (A5-1) is preferably larger than the content of the epoxy compound (A2-1) having 3 ring-type condensed rings and 2 glycidyl ether groups in the molecule. The content ratio (mass ratio) of the polyfunctional oxetane compound (a5-1) to the epoxy compound (a2-1) containing 3-ring fused rings and 2 glycidyl ether groups in the molecule is preferably 1.1/1 to 5/1, more preferably 1.5/1 to 5/1, and still more preferably 2/1 to 5/1 in the polyfunctional oxetane compound (a 5-1)/epoxy compound (a2-1) containing 3-ring fused rings and 2 glycidyl ether groups in the molecule. When the amount is within the above range, a cured film having a high crosslinking density can be easily obtained, and thus the iodine transfer amount can be suppressed.

When the active energy ray-curable composition contains an epoxy compound (a2-1) containing A3-ring fused ring and 2 glycidyl ether groups in the molecule and an oxetane compound (a5), the content of the oxetane compound (a5) is preferably 35% by mass or more, preferably 80% by mass or less, more preferably 75% by mass or less, and further preferably 70% by mass or less, based on the total mass of the curable component (a).

When the active energy ray-curable composition contains the epoxy compound (a2-1) having A3-ring fused ring and 2 glycidyl ether groups in the molecule and the oxetane compound (a5), the content of the epoxy compound (a2-1) having A3-ring fused ring and 2 glycidyl ether groups in the molecule is preferably 1 mass% or more, more preferably 5 mass% or more, preferably less than 35 mass%, and more preferably 30 mass% or less, based on the total mass of the curable component (a).

(viscosity)

The viscosity of the active energy ray-curable adhesive composition may be a viscosity that can be applied by various methods, and may be, for example, 200mPa · s or less, preferably 0.1mPa · s or more and 180mPa · s or less at a temperature of 25 ℃. If the viscosity is too low, it tends to be difficult to form a layer having a desired thickness. On the other hand, if the viscosity is too high, the flow tends to be difficult, and it tends to be difficult to obtain a homogeneous coating film free from unevenness. The viscosity here is a value measured at 10rpm after the temperature of the adhesive is adjusted to 25 ℃ by 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 adhesive composition or an ultraviolet-curable adhesive composition. In the present specification, the active energy ray is defined as an energy ray that can decompose 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.

The electron beam-curable adhesive composition of the present invention can be applied to a substrate for a display device, and the like. For example, the acceleration voltage of the electron beam irradiation is preferably 5kV or more and 300kV or less, and more preferably 10kV or more and 250kV or less. When the acceleration voltage is less than 5kV, the electron beam may not reach the adhesive and may be insufficiently cured, and when the acceleration voltage exceeds 300kV, the penetration force through the sample becomes too strong and the electron beam may be repelled, thereby damaging the transparent protective film and the polarizing plate. The irradiation dose is 5kGy or more and 100kGy or less, and more preferably 10kGy or more and 75kGy or less. When the irradiation dose is less than 5kGy, the adhesive is insufficiently cured, and when it exceeds 100kGy, the optical layer is damaged, the mechanical strength is reduced, and yellowing occurs, and desired optical characteristics cannot be obtained.

The electron beam irradiation is usually performed in an inert gas, but may be performed in the atmosphere or under a condition where a small amount of oxygen is introduced, if necessary. By introducing oxygen appropriately, oxygen inhibition occurs instead in the optical layer that the electron beam first contacts, damage to other optical layers can be prevented, and the electron beam can be effectively irradiated only to the adhesive.

The ultraviolet-curable adhesive composition is not particularly limited, and the irradiation intensity of the active energy ray-curable adhesive composition depends on the composition of the adhesive, but is preferably 10mW/cm ² Above and 1,000mW/cm ² The following. If the intensity of light irradiation to the resin composition is less than 10mW/cm ² The reaction time is too long, and if it exceeds 1,000mW/cm ² The heat radiated from the light source and the heat generated during polymerization of the composition may cause yellowing of the constituent material of the adhesive. The irradiation intensity is preferably an intensity in a wavelength region effective for activation of the cationic photopolymerization initiator (B), more preferably an intensity in a wavelength region of 400nm or less, and still more preferably an intensity in a wavelength region of 280nm to 320 nm. Irradiation is carried out 1 or more times at such light irradiation intensity, preferably at 10mJ/cm ² Above, more preferably 100mJ/cm ² Above and 1,000mJ/cm ² The cumulative light amount is set in the following manner. If the cumulative light quantity for the adhesive is less than 10mJ/cm ² The generation of active species derived from the polymerization initiator is insufficient, and the curing of the adhesive becomes insufficient. On the other hand, if the cumulative light amount exceeds 1,000mJ/cm ² The irradiation time becomes long, which is disadvantageous in productivity improvement. In this case, the wavelength region (UVA (320nm to 390 nm) and UVB (280nm to 320 nm) and the amount of accumulated light thereof) may be appropriately set according to the type of the 1 st retardation layer 30 and the 2 nd retardation layer 40, the combination of the types of adhesives, and the like.

The light source for polymerizing and curing the active energy ray-curable adhesive composition by irradiation with an active energy ray in the present invention is not particularly limited, and examples thereof include a low-pressure mercury lamp, a medium-pressure mercury lamp, a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, a xenon lamp, a halogen lamp, a carbon arc lamp, a tungsten lamp, a gallium lamp, an excimer laser, an LED light source emitting light having a wavelength range of 380nm to 440nm, a chemical lamp, a black light, a microwave-excited mercury lamp, and a metal halide lamp. From the viewpoint of energy stability and device simplicity, an ultraviolet light source having an emission distribution at a wavelength of 400nm or less is preferable.

(storage modulus of the 1 st cured product layer)

From the viewpoint of suppressing corrosion of the conductive layer, the storage modulus (E) of the 1 st cured product layer at a temperature of 80 ℃ ₁ ) Preferably 300MPa toAbove, it is more preferably 500MPa or more, and still more preferably 1000MPa or more. Further, it is preferably 5000MPa or less, more preferably 4000MPa or less, and still more preferably 3500MPa or less. Note that the 1 st cured product layer has a storage modulus (E) ₁ ) The measurement was performed by the method described in the section of examples described later.

The storage modulus (E) of the 1 st cured product layer at a temperature of 80 ℃ from the viewpoints of suppressing corrosion and suppressing crack generation at the time of durability test ₁ ) Storage modulus (E) at 80 ℃ with the 2 nd cured product layer described later ₂ ) Preferably satisfies E ₁ ＞E ₂ If set to E ₁ -E ₂ When Δ E is equal to Δ E, Δ E is more preferably 2000MPa or less, and still more preferably 1500MPa or less.

Preferably, the 1 st cured layer has a storage modulus at a temperature of 30 ℃ that is not too great as a storage modulus at a temperature of 80 ℃. If the difference between the storage modulus at 30 ℃ and the storage modulus at 80 ℃ is too large, metal corrosion tends to occur easily. The difference between the storage modulus at a temperature of 30 ℃ and the storage modulus at a temperature of 80 ℃ is preferably 1500MPa or less.

(glass transition temperature of the 1 st cured product layer)

The glass transition temperature (Tg) of the 1 st cured product layer from the viewpoint of suppressing corrosion of the conductive layer ₁ ) Preferably 65 ℃ or higher, more preferably 70 ℃ or higher, and still more preferably 75 ℃ or higher. Further, it is preferably 200 ℃ or lower, more preferably 150 ℃ or lower, and still more preferably 120 ℃ or lower. Glass transition temperature (Tg) of the 1 st cured layer ₁ ) The measurement was carried out by the method described in the section of examples described later.

(moisture permeability of the 1 st cured product layer)

From the viewpoint of suppressing metal corrosion, the 1 st cured product layer preferably has a low moisture permeability at a temperature of 80 ℃. The cured layer 1 having a thickness of 30 μm preferably has a moisture permeability of 1500 g/(m) measured by the cup method specified in JIS Z0208 at a temperature of 80 ℃ and a relative humidity of 90% ² 24hr) or less, more preferably 1000 g/(m) ² 24hr) or less, more preferably 950 g/(m) ² 24hr) or less. The transparent layerThe humidity is usually 100 g/(m) ² 24hr) above.

Specifically, the moisture permeability J of the 1 st cured film can be determined as follows: a laminate (for example, a laminate of 20 μm triacetyl cellulose film/5 μm adhesive layer/1 st cured product layer having a thickness of 30 μm) having the 1 st cured product layer formed on a base film or the like having a known moisture permeability was prepared, and the moisture permeability of the laminate was measured by the above-described method and the measurement result was obtained based on the following formula.

1/Jt＝(1/J)-+-(1/Jsub)

In the above formula, Jt is the moisture permeability of the laminate, and Jsub is the moisture permeability of the layer from which the 1 st cured product layer has been removed. When the moisture permeability of the laminate was measured in accordance with JIS Z0208, the laminate was mounted in a cup so that the cured film faced outward.

For example, a laminate comprising a layer of 20 μm triacetyl cellulose film, 5 μm adhesive layer, and 30 μm first cured product layer has a moisture permeability of preferably 1000 g/(m) measured at 80 ℃ and 90% relative humidity by the cup method specified in JIS Z0208 ² 24hr) or less, more preferably 950 g/(m) ² 24hr) or less. The moisture permeability is usually 100 g/(m) ² 24hr) above.

(retardation layer)

The optical laminate of the present invention comprises a retardation layer 20, and the retardation layer 20 has at least one retardation-developing layer of a polymer which is a polymerizable liquid crystal compound. The retardation layer 20 is not particularly limited as long as it includes at least one retardation-developing layer that imparts a predetermined retardation to light, and may be, for example, an optical compensation layer such as an 1/2-wavelength layer, a 1/4-wavelength layer, or a positive C plate. The retardation layer may be a retardation layer having a positive dispersibility or a retardation layer having a reverse wavelength dispersibility. The retardation layer 20 may be formed of only the retardation-developing layer, or may include both the retardation-developing layer and another layer, as long as it includes at least one retardation-developing layer. Examples of the other layer include a base layer, an alignment film layer, and a protective layer. Note that the other layers do not affect the value of the phase difference. The retardation layer 20 may be composed of 2 layers, i.e., a1 st retardation layer 30 and a2 nd retardation layer 40. Hereinafter, a laminate in which the 1 st retardation layer 30 and the 2 nd retardation layer 40 are bonded to each other via a2 nd cured product layer 50 described later is also referred to as a retardation layer laminate 60.

Examples of the retardation layer include a layer of a polymer containing a polymerizable liquid crystal compound (hereinafter, also referred to as a liquid crystal layer) and a stretched film. At least one of the 1 st retardation layer 30 and the 2 nd retardation layer 40 is preferably a liquid crystal layer. When the 1 st retardation layer 30 is a liquid crystal layer, the 1 st retardation layer 30 is preferably a liquid crystal layer whose surface on the 2 nd cured product layer 50 side is a phase difference developing layer. When the 2 nd retardation layer 40 is a liquid crystal layer, the 2 nd retardation layer 40 is preferably a liquid crystal layer whose surface on the 2 nd cured product layer 50 side is a retardation developing layer. The retardation-developing layer as a liquid crystal layer is generally easier to be made thinner than the retardation-developing layer as a stretched film.

From the viewpoint of adhesion, the light transmittance at a wavelength of 320nm of at least one of the 1 st retardation layer 30 and the 2 nd retardation layer 40 is preferably 5% or more, more preferably 10% or more, and still more preferably 30% or more. The light transmittance can be measured by the measurement method described in the section of examples described later.

At least one of the 1 st retardation layer 30 and the 2 nd retardation layer 40 preferably has a light transmittance at a wavelength of 380nm of 0% or more and 10% or less, and a light transmittance at a wavelength of 400nm of 30% or more, more preferably has a light transmittance at a wavelength of 380nm of 0% or more and 5% or less, and has a light transmittance at a wavelength of 400nm of 35% or more, and still more preferably has a light transmittance at a wavelength of 380nm of 0% or more and 1% or less, and has a light transmittance at a wavelength of 400nm of 40% or more.

When each of the 1 st retardation layer 30 and the 2 nd retardation layer 40 is composed of only a retardation developing layer, the thickness thereof 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.

When the 1 st retardation layer 30 and the 2 nd retardation layer 40 each include a layer (base layer, alignment film layer, protective layer, etc.) other than the retardation-developing layer, the thickness of the whole is preferably 0.5 μm or more and 300 μm or less, and more preferably 0.5 μm or more and 150 μm or less.

The combination of the 1 st retardation layer 30 and the 2 nd retardation layer 40 includes, for example

i)1/2 wavelength layer in combination with 1/4 wavelength layer,

ii)1/2 wavelength layer in combination with an optical compensation layer,

iii)1/4 wavelength layer in combination with an optical compensation layer, and the like.

i) In the case of (1), the 1 st retardation layer 30 is preferably an 1/2 wavelength layer, and the 2 nd retardation layer 40 is preferably a 1/4 wavelength layer.

in the case of ii), the 1 st retardation layer 30 is preferably an 1/2-wavelength layer, the 2 nd retardation layer 40 is preferably an optical compensation layer, more preferably, the 1 st retardation layer 30 is a 1/2-wavelength layer, and the 2 nd retardation layer 40 is a positive C plate.

iii) the 1 st retardation layer 30 is preferably an 1/4 wavelength layer, the 2 nd retardation layer 40 is an optical compensation layer, more preferably the 1 st retardation layer 30 is a 1/4 wavelength layer, and the 2 nd retardation layer 40 is a positive C plate.

The 1/2 wavelength layer has a function of changing the direction (polarization direction) of linearly polarized light by giving a phase difference of pi (═ λ/2) to the electric field vibration direction (polarization plane) of incident light. When circularly polarized light is incident, the rotation direction of the 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. Although Re (λ) ═ λ/2 may be achieved at an arbitrary wavelength in the visible light region, it is preferably achieved at a wavelength of 550 nm. Re (550) as an in-plane retardation value at a wavelength of 550nm preferably satisfies 210nm & lt Re (550) & lt 300 nm. Further, it is more preferable to satisfy 220 nm. ltoreq. Re (550). ltoreq.290 nm.

The 1/4 wavelength layer has a function of converting linearly polarized light of a certain specific wavelength into circularly polarized light (or converting circularly polarized light into linearly polarized light) while giving a phase difference of pi/2 (λ/4) to the electric field vibration direction (polarization plane) of incident 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 the condition that Re (λ) ═ λ/4, and it is sufficient to achieve it at any wavelength in the visible light region, but it is preferably achieved at a wavelength of 550 nm. Re (550) as an in-plane retardation value at a wavelength of 550nm preferably satisfies 100 nm. ltoreq. Re (550). ltoreq.160 nm. Further, it is more preferable that 110 nm. ltoreq. Re (550). ltoreq.150 nm be satisfied.

Examples of the optical compensation layer include a positive a plate and a positive C plate. The positive A plate satisfies a relationship of Nx > Ny where Nx is a refractive index in a slow axis direction in a plane, Ny is a refractive index in a fast axis direction in the plane, and Nz is a refractive index in a thickness direction. The positive A plate preferably satisfies the relationship of Nx > Ny ≧ Nz. The positive a plate also functions as an 1/4 wavelength layer. The positive C plate satisfies the relation that Nz is more than Nx and is more than or equal to Ny.

The reverse wavelength dispersibility is an optical property that an in-plane retardation value at a short wavelength is smaller than an in-plane retardation value at a long wavelength, and preferably satisfies the following formula (2):

Re(450)≤Re(550)≤Re(650) (2)。

re (λ) represents an in-plane retardation value for light having a wavelength of λ nm.

The optical properties of the retardation layer can be adjusted by the alignment state of the liquid crystal compound constituting the retardation-developing layer or the stretching method of the stretched film constituting the retardation-developing layer. By appropriately adjusting the optical characteristics of the retardation layer, a polarizing plate composite having antireflection performance can be obtained by laminating the retardation layer laminate and the linear polarizing plate.

(retardation developing layer formed of liquid Crystal layer)

The case where the phase difference developing layer is a liquid crystal layer will be described. Fig. 2 is a schematic cross-sectional view schematically showing an example of a retardation layer including a retardation developing layer as a liquid crystal layer and another layer. The 1 st retardation layer 30 shown in fig. 2 is formed by laminating a base material layer 31, an alignment layer 32, and a retardation developing layer 33 as a liquid crystal layer in this order. The retardation layer is not limited to the 1 st retardation layer 30 shown in fig. 2 as long as it includes the retardation-developing layer 33 as a liquid crystal layer, and may be a structure in which the base material layer 31 is peeled from the 1 st retardation layer 30 and only the alignment layer 32 and the retardation-developing layer 33 are formed, or a structure in which the base material layer 31 and the alignment layer 32 are peeled from the 1 st retardation layer 30 and only the retardation-developing layer 33 as a liquid crystal layer is formed. From the viewpoint of making the film thinner, the retardation layer is preferably formed by peeling the base material layer 31, and more preferably formed only by the retardation developing layer 33 as a liquid crystal layer. The base material layer 31 functions as a support layer for supporting the alignment layer 32 formed on the base material layer 31 and the retardation development layer 33 serving as a liquid crystal layer. The base material layer 31 is preferably a film formed of a resin material.

As the resin material, for example, a resin material excellent in transparency, mechanical strength, thermal stability, stretchability, and the like is used. Specific examples thereof include 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 resins such as (meth) acrylic acid and polymethyl (meth) acrylate; cellulose ester resins such as triacetyl cellulose, diacetyl cellulose, and cellulose acetate propionate; vinyl alcohol resins such as polyvinyl alcohol and polyvinyl acetate; a polycarbonate-based resin; a polystyrene-based resin; a polyarylate-based resin; a polysulfone-based resin; a polyether sulfone-based resin; a polyamide resin; a polyimide-based resin; a polyether ketone resin; polyphenylene sulfide-based resin; polyphenylene ether resins, and mixtures and copolymers thereof. Among these resins, any of cyclic polyolefin resins, polyester resins, cellulose ester resins, and (meth) acrylic resins, or a mixture thereof is preferably used. The "(meth) acrylic acid" means "at least 1 kind of acrylic acid and methacrylic acid".

The base layer 31 may be a single layer of 1 kind of the above-mentioned resin or a mixture of 2 or more kinds of the above-mentioned resin, or may have a multilayer structure of 2 or more layers. In the case of having a multilayer structure, the resins constituting the respective layers may be the same or different.

Any additive may be added to the resin material constituting the resin film. Examples of the additive include an ultraviolet absorber, an antioxidant, a lubricant, a plasticizer, a mold release agent, an anti-coloring agent, 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, and is preferably 5 μm or more and 200 μm or less, more preferably 10 μm or more and 200 μm or less, and further preferably 10 μm or more and 150 μm or less, in general, from the viewpoint of strength, handling properties, and the like.

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

The alignment layer 32 has an alignment regulating force for aligning the liquid crystal compound contained in the retardation developing layer 33 as a liquid crystal layer formed on the alignment layer 32 in a desired direction. Examples of the alignment layer 32 include an alignment polymer layer formed of an alignment polymer, a photo-alignment polymer layer formed of a photo-alignment polymer, and a groove alignment layer having a concave-convex pattern and a plurality of grooves (grooves) on the surface of the layer. 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 composition having the alignment polymer dissolved in the solvent is applied to the base material layer 31, the solvent is removed, and rubbing treatment is performed as necessary, whereby an alignment polymer layer can be formed. In this case, the orientation regulating force can be arbitrarily adjusted by the surface state of the oriented polymer and the rubbing condition in the oriented polymer layer formed of the oriented polymer.

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

The trench alignment layer can be formed by, for example, the following method or the like: a method of forming a concave-convex pattern by exposing and developing the surface of a photosensitive polyimide film through an exposure mask having a slit with a pattern shape; a method of forming an uncured layer of an active energy ray-curable resin on a plate-like master having grooves on the surface thereof, transferring the layer to the base material layer 31, and curing the layer; a method of forming an uncured layer of the active energy ray-curable resin on the base layer 31, pressing a roll-shaped master having irregularities against the layer, etc., to form irregularities, and then curing the irregularities.

The retardation-developing layer 33 of the liquid crystal layer is not particularly limited as long as it is a layer that imparts a predetermined retardation to light, and examples thereof include a retardation-developing layer for 1/2 wavelength layer, a retardation-developing layer for 1/4 wavelength layer, a retardation-developing layer for an optical compensation layer such as a positive C plate, and a retardation-developing layer for a reverse wavelength dispersion 1/4 wavelength layer.

The retardation developing layer 33 serving as a liquid crystal layer can be formed using a known liquid crystal compound. The type of the liquid crystal compound is not particularly limited, and a rod-like liquid crystal compound, a discotic liquid crystal compound, and a mixture thereof can be used. The liquid crystal compound may be a polymeric liquid crystal compound, a polymerizable liquid crystal compound, or a mixture thereof. Examples of the liquid crystal compound include those described in Japanese patent application laid-open No. 11-513019, Japanese patent application laid-open No. 2005-289980, Japanese patent application laid-open No. 2007-108732, Japanese patent application laid-open No. 2010-244038, Japanese patent application laid-open No. 2010-31223, Japanese patent application laid-open No. 2010-270108, Japanese patent application laid-open No. 2011-6360, Japanese patent application laid-open No. 2011-207765, Japanese patent application laid-open No. 2016-81035, International publication No. 2017/043438, and Japanese patent application laid-open No. 2011-207765.

For example, when a polymerizable liquid crystal compound is used, the retardation-developing layer 33 can be formed by forming a coating film by applying a composition containing the polymerizable liquid crystal compound onto the alignment layer 32 and curing the coating film. The thickness of the phase difference-developing 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 a polymerizable liquid crystal compound may contain a polymerization initiator, a polymerizable monomer, a surfactant, a solvent, an adhesion improving agent, a plasticizer, an alignment agent, and the like in addition to the liquid crystal compound. As a method for applying the composition containing the polymerizable liquid crystal compound, a known method such as a die coating method can be mentioned. Examples of a method for curing a composition containing a polymerizable liquid crystal compound include known methods such as irradiation with active energy rays (e.g., ultraviolet rays).

(retardation layer having stretched film as retardation-developing layer)

The case where the retardation-exhibiting layer is a stretched film will be described. The stretched film is generally obtained by stretching a substrate. As a method of stretching the substrate, for example, a roll (wound body) around which the substrate is wound in a roll shape is prepared, the substrate is continuously wound from the wound body, and the wound substrate is conveyed to a heating furnace. The temperature setting of the heating furnace is set to a range from the vicinity of the glass transition temperature (. degree.C.) of the substrate to [ glass transition temperature +100] (. degree.C.), preferably to a range from the vicinity of the glass transition temperature (. degree.C.) to [ glass transition temperature +50] (. degree.C.). In this heating furnace, when the substrate is stretched in the traveling direction or in the direction orthogonal to the traveling direction, uniaxial or biaxial thermal stretching treatment is performed obliquely at an arbitrary angle by adjusting the conveyance direction and the tension. The stretching ratio is usually 1.1 to 6 times, preferably 1.1 to 3.5 times.

The method of stretching in the oblique direction is not particularly limited as long as the orientation axis can be continuously inclined at a desired angle, and a known stretching method can be employed. Examples of such a drawing method include the methods described in Japanese patent application laid-open Nos. 50-83482 and 2-113920. When a retardation is imparted to a film by stretching, the thickness after stretching is determined by the thickness before stretching and the stretching magnification.

The substrate is typically a transparent substrate. The transparent substrate means a substrate having transparency which can transmit light, particularly visible light, and the transparency means a characteristic that transmittance for light having a wavelength of 380nm or more and 780nm or less is 80% or more. Specific examples of the transparent substrate include a light-transmitting resin substrate. Examples of the resin constituting the light-transmitting resin substrate include polyolefins such as polyethylene and polypropylene; cyclic olefin resins such as norbornene polymers; polyvinyl alcohol; polyethylene terephthalate; polymethacrylates; a polyacrylate; cellulose esters such as triacetyl cellulose, diacetyl cellulose, and cellulose acetate propionate; polyethylene naphthalate; a polycarbonate; polysulfones; polyether sulfone; a polyether ketone; polyphenylene sulfide and polyphenylene oxide. From the viewpoint of ease of acquisition and transparency, polyethylene terephthalate, polymethacrylate, cellulose ester, cycloolefin resin, or polycarbonate is preferable.

Cellulose ester is a substance in which a part or all of hydroxyl groups contained in cellulose are esterified, and is easily available from the market. In addition, cellulose ester substrates are also readily available from the market. Examples of commercially available cellulose ester substrates include "FUJITAC (registered trademark) Film" (fujifilm corporation); "KC 8UX 2M", "KC 8 UY" and "KC 4 UY" (Konica Minolta Opto Co., Ltd.) and the like.

Polymethacrylates and polyacrylates (hereinafter, polymethacrylates and polyacrylates are sometimes collectively referred to as (meth) acrylic resins).

Examples of the (meth) acrylic resin include homopolymers of alkyl methacrylate or alkyl acrylate, and copolymers of alkyl methacrylate and alkyl acrylate. Specific examples of the alkyl methacrylate include methyl methacrylate, ethyl methacrylate, and propyl methacrylate, and specific examples of the alkyl acrylate include methyl acrylate, ethyl acrylate, and propyl acrylate. As the (meth) acrylic resin, a resin sold as a general-purpose (meth) acrylic resin can be used. As the (meth) acrylic resin, a resin called an impact-resistant (meth) acrylic resin may also be used.

In order to further improve the mechanical strength, it is also preferable to contain rubber particles in the (meth) acrylic resin. The rubber particles are preferably acrylic rubber particles. The acrylic rubber particles are particles having rubber elasticity obtained by polymerizing an acrylic monomer containing an alkyl acrylate such as butyl acrylate or 2-ethylhexyl acrylate as a main component in the presence of a polyfunctional monomer. The acrylic rubber particles may be a single layer of particles having rubber elasticity, or may be a multilayer structure having at least one rubber elastic layer. Examples of the acrylic rubber particles having a multilayer structure include: particles obtained by using the particles having rubber elasticity as a core and covering the periphery thereof with a hard alkyl methacrylate polymer; particles in which a hard alkyl methacrylate polymer is used as a core and the periphery thereof is covered with the above-mentioned acrylic polymer having rubber elasticity; and particles obtained by covering the periphery of a hard core with a rubber-elastic acrylic polymer and further covering the periphery with a hard alkyl methacrylate polymer. The rubber particles formed of the elastic layer generally have an average diameter in the range of 50nm to 400 nm.

The content of the 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 sold in a mixed state, commercially available products thereof can be used. Examples of commercially available (meth) acrylic resins containing acrylic rubber particles include "HT 55X" and "techinlloy S001" sold by sumitomo chemical corporation. "TECHNOLLOY S001" is sold in the form of a membrane.

The cycloolefin-based resin can be easily obtained from the market. Examples of commercially available cycloolefin resins include "Topas" (registered trademark) [ Ticona (d) ], "Arton" (registered trademark) [ JSR corporation ], "ZEONOR" (registered trademark) [ japan ZEON corporation ], "ZEONEX" (registered trademark) [ japan ZEON corporation ], and "APEL" (registered trademark) [ mitsui chemical corporation ]. The cycloolefin resin can be formed into a film by a known method such as a solvent casting method or a melt extrusion method, and the film can be formed into a substrate. In addition, a commercially available cycloolefin resin base material may be used. Examples of commercially available cycloolefin resin substrates include "escina" (registered trademark) [ water chemical industry co., ltd. ]), "SCA 40" (registered trademark) [ water chemical industry co., ltd. ], "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, a chain olefin, and an aromatic compound having a vinyl group, the content ratio of the structural unit derived from the cyclic olefin is usually 50 mol% or less, and preferably 15 mol% or more and 50 mol% or less, based on the total structural units of the copolymer. 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 terpolymer 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 usually 5 mol% or more and 80 mol% or less with respect to the total structural units of the copolymer, and the content ratio of the structural unit derived from the aromatic compound having a vinyl group is usually 5 mol% or more and 80 mol% or less with respect to the total structural units of the copolymer. Such a terpolymer has an advantage that the amount of expensive cyclic olefin used in the production thereof can be reduced.

(second cured product layer)

In the case where the retardation layer includes the retardation laminate 60 of the 1 st retardation layer 30 and the 2 nd retardation layer 40, the 2 nd cured layer 50 may be disposed to bond the 1 st retardation layer 30 and the 2 nd retardation layer 40. The thickness of the 2 nd 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 2 nd cured product layer 50 may be, for example, 0.5 μm or more.

The 2 nd cured product layer 50 contains a cured product of an active energy ray-curable adhesive composition. The description of the 1 st cured product layer 14 is applied to the active energy ray-curable adhesive composition used for the 2 nd cured product layer 50. The active energy ray-curable adhesive composition used in the 2 nd cured layer 50 may not contain any of a photosensitizer and a photo-sensitizer.

The active energy ray-curable adhesive composition contained in the 2 nd cured layer 50 may be the same as or different from the active energy ray-curable adhesive composition contained in the 1 st cured layer 14. The 2 nd cured layer 50 is preferably a cured layer of a cationically polymerizable adhesive composition.

(storage modulus of the 2 nd cured product layer)

From the viewpoint of suppressing the retardation crack during processing, the storage modulus of the 2 nd cured product layer at 30 ℃ is preferably 300MPa or more, more preferably 500MPa or more, and still more preferably 1000MPa or more. Further, it is preferably 5000MPa or less, more preferably 4000MPa or less, and still more preferably 3500MPa or less. The storage modulus of the 2 nd cured product layer was measured by the method described in the section of examples described later.

From the viewpoint of suppressing corrosion of the conductive layer, the storage modulus (E) of the 2 nd cured product layer at a temperature of 80 ℃ ₂ ) Preferably 20MPa or more, more preferably 30MPa or more, and still more preferably 40MPa or more. Further, it is preferably 100MPa or less, more preferably 90MPa or less, and further preferably 80MPa or less. Note that the storage modulus (E) of the 2 nd cured product layer ₂ ) The measurement was carried out by the method described in the following examples.

(glass transition temperature of the No. 2 cured product layer)

The glass transition temperature (Tg) of the 2 nd cured product layer from the viewpoint of suppressing phase difference cracking during processing ₂ ) Preferably 200 ℃ or lower, more preferably 150 ℃ or lower, and still more preferably 120 ℃ or lower. Further, it is preferably 40 ℃ or higher, more preferably 50 ℃ or higher, further preferably 60 ℃ or higher, and particularly preferably 70 ℃ or higher. Glass transition temperature (Tg) of the 2 nd cured layer ₂ ) The measurement was performed by the method described in the section of examples described later.

(adhesive layer)

The laminate 100 has an adhesive layer 70 on the side of the phase difference layer 20 opposite to the 1 st cured product layer 14. The pressure-sensitive adhesive layer may be composed of a pressure-sensitive adhesive composition containing a resin such as a (meth) acrylic, rubber, urethane, ester, silicone, or polyvinyl ether resin as a main component. Among them, a pressure-sensitive adhesive composition containing a (meth) acrylic resin excellent in transparency, weather resistance, heat resistance and the like as a base polymer is preferable. The adhesive composition may be active energy ray-curable or heat-curable. The thickness of the pressure-sensitive adhesive layer 18 is usually 3 μm or more and 30 μm or less, and preferably 3 μm or more and 25 μm or less.

As the (meth) acrylic resin (base polymer) used in the adhesive composition, for example, a polymer or copolymer using 1 or 2 or more kinds of (meth) acrylic acid esters such as butyl (meth) acrylate, ethyl (meth) acrylate, isooctyl (meth) acrylate, and 2-ethylhexyl (meth) acrylate as monomers is preferably used. It is preferred to copolymerize the polar monomer with the base polymer. Examples of the polar monomer include monomers having a carboxyl group, a hydroxyl group, an amide group, an amino group, an epoxy group, and the like, such as (meth) acrylic acid, 2-hydroxypropyl (meth) acrylate, hydroxyethyl (meth) acrylate, (meth) acrylamide, N-dimethylaminoethyl (meth) acrylate, and glycidyl (meth) acrylate.

The adhesive composition may comprise only the above-mentioned base polymer, but usually also contains a crosslinking agent. As the crosslinking agent, there can be exemplified: a crosslinking agent which is a metal ion having a valence of 2 or more and forms a metal carboxylate salt with a carboxyl group; a crosslinking agent which is a polyamine compound and forms an amide bond with a carboxyl group; a crosslinking agent which is a polyepoxy compound, a polyol, and forms an ester bond between the polyepoxy compound and a carboxyl group; a polyisocyanate compound and a crosslinking agent which forms an amide bond between the polyisocyanate compound and a carboxyl group. Among them, polyisocyanate compounds are preferable.

In one embodiment 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 ℃ and a relative humidity of 90% for 250 hours is 900mg/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 amount refers to the content of iodine element in the adhesive layer.

If the amount of iodine contained in the adhesive layer is 900mg/kg or less, corrosion of the conductive layer can be suppressed. The amount of iodine contained in the pressure-sensitive adhesive layer is preferably 800mg/kg or less, and more preferably 700mg/kg or less.

(method of producing laminate)

An example of a method for producing a laminate according to the present invention will be described with reference to fig. 3. As shown in fig. 3(a), a linear polarizing plate 10 in which a polarizer 13 and a thermoplastic resin film 11 are laminated with an adhesive layer 12 interposed therebetween is produced. As shown in fig. 3(B), a1 st retardation layer 30 including a1 st retardation layer 31, a1 st alignment layer 32, and a1 st base material layer 33 and a2 nd retardation layer 40 including a2 nd retardation layer 43, a2 nd alignment layer 42, and a2 nd base material layer 41 are laminated via a2 nd cured material layer 50, and as shown in fig. 3(C), a retardation layer laminate 60 in which the 1 st base material layer 33, the 1 st alignment layer 32, the 1 st retardation layer 31, the 2 nd cured material layer 50, the 2 nd retardation layer 43, the 2 nd alignment layer 42, and the 2 nd base material layer 41 are laminated in this order is produced. As shown in fig. 3(D), the polarizing plate 10 is laminated with the 1 st retardation layer 30 side of the retardation layer laminate 60 and the polarizer 13 side thereof via the 1 st cured layer 14 to obtain a laminate 80.

Examples of the method for bonding the polarizing plate 13 to the thermoplastic resin film 11 include the following methods: the adhesive composition is applied to either or both of the bonding surfaces of the polarizing plate 13 and the thermoplastic resin film 11, the bonding surface of the other is laminated on the one, and the adhesive composition constituting the adhesive layer 12 is cured.

Examples of the method for bonding the 1 st retardation layer 30 and the 2 nd retardation layer 40 include the following methods: an active energy ray-curable adhesive composition is applied to either or both of the bonding surface of the 1 st retardation layer 30 and the bonding surface of the 2 nd retardation layer 40, and the bonding surfaces of the other are laminated on each other, and the active energy ray-curable adhesive constituting the 2 nd cured layer 50 is cured. The active energy ray for curing the active energy ray-curable adhesive constituting the 2 nd cured layer 50 may be irradiated from either one or both of the 1 st phase difference layer 30 and the 2 nd phase difference layer 40.

Examples of the method for bonding the linear polarizing plate 10 and the retardation layer laminate 60 include the following methods: an active energy ray-curable adhesive composition is applied to either or both of the bonding surface of the linear polarizing plate 10 and the bonding surface of the retardation layer laminate 60, and the bonding surface of the other is laminated to one, and the active energy ray-curable adhesive constituting the 1 st cured layer 14 is cured. From the viewpoint of adhesion, it is preferable to apply the active energy ray-curable adhesive composition only to the bonding surface of the retardation layer laminate 60. The active energy ray for curing the active energy ray-curable adhesive constituting the 1 st cured layer 14 may be irradiated from either one or both of the linear polarizing plate 10 and the phase difference layer laminate 60.

Either or both of the mating surfaces may be subjected to corona treatment, plasma treatment, or the like, or a primer layer may be formed. In the application of the aqueous adhesive composition and the active energy ray-curable adhesive composition, various application 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 comprising a laminate 80 and a pressure-sensitive adhesive layer (a pressure-sensitive adhesive layer laminated on the 2 nd retardation layer 40 side) as shown in fig. 3D. Further, a laminate including a laminate obtained by peeling at least one of the 1 st base material layer 33 and the 2 nd base material layer 41 from the laminate 80 shown in fig. 3(D) and a pressure-sensitive adhesive layer may be used. Further, a laminate including a laminate obtained by peeling the 1 st base material layer 33 and the 1 st alignment layer 32 from the laminate 80 shown in fig. 3(D) and a pressure-sensitive adhesive layer may be used, or a laminate including a laminate obtained by peeling the 2 nd base material layer 41 and the 2 nd alignment layer 42 from the laminate 80 shown in fig. 3(D) and a pressure-sensitive adhesive layer may be used.

(conductive layer)

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

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

The metal constituting the metal wiring layer may be, for example, a layer containing at least 1 metal element selected from the group consisting of aluminum, copper, silver, iron, tin, zinc, platinum, nickel, molybdenum, chromium, tungsten, lead, titanium, palladium, indium, and an alloy containing 2 or more metals thereof. Among them, a layer containing at least 1 metal element selected from aluminum, copper, silver, and gold is preferable from the viewpoint of conductivity, and a layer containing an aluminum element is more preferable from the viewpoint of conductivity and cost. In the case of a layer containing copper, blackening treatment may be performed from the viewpoint of preventing reflection of light. The blackening treatment means oxidizing the surface of the conductive layer to thereby oxidize Cu ₂ O or CuO precipitates.

The conductive layer may be a layer containing graphene, zinc oxide, or the like.

The conductive layer is, for example, disposed on the substrate. Examples of a method for forming a conductive layer on a 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, a cyclic olefin copolymer, triacetyl cellulose, polyvinyl alcohol, polyimide, polystyrene, biaxially stretched polystyrene, or the like. The glass substrate may be formed of, for example, soda lime glass, low alkali glass, alkali-free glass, or the like. The conductive layer may be formed over the entire surface of the substrate or may be formed in a part thereof.

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

When the conductive layer is a metal wiring layer (particularly, a metal mesh), the metal wiring may be disposed at a predetermined interval in the longitudinal and transverse directions of a plane on the substrate, for example. In this case, the opening may be filled with a resin (an adhesive or the like), or the metal wiring layer may be embedded in the resin (the adhesive or the like). When a resin or the like is used, the conductive layer is formed of both a metal wiring and a resin (adhesive).

The line width of the metal wiring (particularly, the metal mesh) is usually 10 μm or less, preferably 5 μm or less, more preferably 3 μm or less, and usually 0.1 μm or more, preferably 0.5 μm or more, more preferably 1 μm or more. The line width of the metal wiring layer may be a combination of these upper and lower limits, and is preferably 0.5 to 5 μm, and 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, and is usually 10 μm or less, preferably 3 μm or less, more preferably 1 μm or less, particularly preferably 0.5 μm or less, usually 0.01 μm or more, preferably 0.05 μm or more, more preferably 0.1 μm or more. The thickness of the conductive layer may be a combination of these upper and lower values, and is preferably 0.01 to 3 μm, and more preferably 0.05 to 1 μm. When the conductive layer is a metal wiring layer and the metal wiring layer is formed of both a resin (such as an adhesive) and a metal wiring, the thickness of the conductive layer is a thickness including the resin.

The method for producing the conductive layer is not particularly limited, and the conductive layer may be a laminate of metal foils, or may be a conductive layer formed by vacuum deposition, sputtering, wet coating, ion plating, inkjet printing, gravure printing, electrolytic plating, or electroless plating, preferably a conductive layer formed by sputtering, inkjet printing, or gravure printing, and more preferably a conductive layer formed by sputtering.

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

An optical laminate including a conductive layer (e.g., a conductive transparent metal oxide layer, a metal wiring layer, or the like) is useful for a touch input type liquid crystal display device having a touch panel function, but a dichroic dye (iodine) contained in a polarizing plate is moved to the conductive layer and easily corrodes the conductive layer. In particular, when a metal wiring layer such as a metal mesh is used, the conductive layer is more likely to be corroded due to the narrow line width. However, the optical layered body of the present invention can effectively suppress the migration of the dichroic dye to the conductive layer, and effectively prevent the corrosion of the conductive layer.

(use)

The laminate can be used for 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. Examples of the image display device include a liquid crystal display device, an organic Electroluminescence (EL) display device, an inorganic Electroluminescence (EL) display device, a touch panel display device, an electron emission display device (for example, a field emission display device (FED), a surface field emission display device (SED)), electronic paper (a display device using electronic ink or an electrophoretic element), a plasma display device, a projection display device (for example, a Grating Light Valve (GLV) display device, a display device having a Digital Micromirror Device (DMD)), a piezoelectric ceramic display device, and the like. The liquid crystal display device further includes any one of a transmission type liquid crystal display device, a semi-transmission type liquid crystal display device, a reflection type liquid crystal display device, a direct-view type liquid crystal display device, a projection type liquid crystal display device, and the like. These image display devices may be image display devices that display two-dimensional images or may be stereoscopic image display devices that display three-dimensional images. In particular, a polarizing plate composite that is a circularly polarizing plate can be effectively used in an organic Electroluminescence (EL) display device that can include an image display panel having a bent portion.

The optical laminate may function as a circularly polarizing plate or an antireflection film. The optical laminate may be disposed on the viewing side of the image display layer panel with the polarizing film oriented on the viewing side. The laminate is preferable as a circularly polarizing plate or an antireflection film used for an in-vehicle image display device.

Examples

The present invention will be described in more detail below with reference to examples. In the examples, "%" and "part(s)" are% by mass and part(s) by mass unless otherwise specified.

(evaluation of Metal Corrosion resistance)

The laminates obtained in examples and comparative examples were cut into test pieces of 25mm × 50mm in size, and bonded to the metal layer side of the glass substrate with a metal layer via the adhesive layer. As the glass substrate with a metal layer, a glass substrate (manufactured by Geomatec) in which a metal aluminum layer having a thickness of about 500nm was laminated on the surface of an alkali-free glass by sputtering was used. The optical laminate thus obtained was stored in an oven at a temperature of 85 ℃ and a relative humidity of 85% for 250 hours, and then irradiated with light from the back surface of the glass substrate, and the state of the metal layer in the portion to which the optical laminate was bonded was observed from the front surface of the polarizing plate through a magnifying glass, and occurrence of pitting corrosion (occurrence of holes having a diameter of 0.1mm or more and capable of transmitting light) was evaluated according to the following criteria. The results are shown in tables 2 and 4.

Very good: the number of pitting corrosion generated on the surface of the metal layer is 4 or less,

o: the number of pitting corrosion generated on the surface of the metal layer is 10 or less,

x: a large amount of pitting is generated in front of the surface of the metal layer.

(evaluation of iodine amount in adhesive layer)

The optical laminates obtained in examples and comparative examples were cut into test pieces of 25mm × 50mm in size, and bonded to alkali-free glass (EAGLE XG manufactured by Corning corporation) via an adhesive layer. The optical laminate bonded to the glass was stored in an oven at a temperature of 80 ℃ and a relative humidity of 90% for 250 hours. Then, the glass was peeled off from the optical laminate, and only the adhesive was scraped off. Based on the obtained binder, the amount of iodine (mg/kg) contained in the binder was quantified using oxidative combustion ion chromatography under the following apparatus and conditions. The results are shown in tables 2 and 4.

(1) Burning of test specimens

An apparatus: AQF-2100H manufactured by Analytech, Mitsubishi chemical corporation

Combustion conditions

Combustion temperature: 1100 deg.C

Gas flow rate: the argon flow rate is 200 mL/min,

the oxygen flow rate is 400 mL/min,

humidification Air flow rate of 100 mL/min

(2) Ion chromatography

An apparatus: integrion manufactured by Thermo Fisher Scientific

Column: IonPac AS19 manufactured by Thermo Fisher Scientific

Measurement conditions

Eluent: gradient of KOH

Flow rate: 1.0 mL/min

Injection amount: 100 μ L

Measurement mode: inhibition type

A detector: electrical conductivity of

(measurement of adhesion)

The laminates produced in examples and comparative examples were cut into a size of 200mm in length × 25mm in width, and the pressure-sensitive adhesive layer surfaces thereof were bonded to soda glass substrates.

Then, a blade of a dicing blade was inserted between the polarizing plate and the λ/2 retardation layer, and the peeled portion was peeled off from the end portion by 30mm in the longitudinal direction, and the peeled portion was held by a jig portion of a universal tensile tester ("AG-1" manufactured by Shimadzu corporation). The test piece in this state was subjected to a temperature of 23 ℃ in an atmosphere of 55% relative humidity in accordance with JIS K6854-2: 1999 "adhesive-peel adhesion Strength test method-part 2: 180 degree peel ", 180 degree peel test was performed at a jig moving speed of 300 mm/min, and the average peel force of 170mm length excluding 30mm of the jig part was obtained and evaluated based on the following criteria. The results are shown in tables 2 and 4.

O: 180 DEG peeling force of 1.0N or more

And (delta): a 180 DEG peeling force of 0.5N or more and less than 1.0N

(measurement of storage modulus and glass transition temperature of adhesive layer at 80 ℃ C.)

One surface of a cyclic polyolefin resin film having a thickness of 50 μm was coated with any of the adhesives 1 to 5 described later by using a coater [ rod coater, first chemical and chemical Co., Ltd ], and a cyclic polyolefin resin film having a thickness of 50 μm was further laminated on the coated surface. Next, the cumulative light amount was 1500mJ/cm using "D Bulb" manufactured by Fusion UV Systems ² The adhesive layer is cured by ultraviolet irradiation (UVB). The resulting film was cut into a size of 5mm × 30mm, and the cyclic polyolefin resin film was peeled off to obtain a cured film of the adhesive. The cured film was held at a distance of 2cm from each other by a dynamic viscoelasticity measuring apparatus "DVA-220" manufactured by IT measurement control corporation such that the long side thereof was in the stretching direction, the stretching and shrinking frequencies were set to 10Hz, the temperature increase rate was set to 10 ℃/min, and the storage modulus at a temperature of 80 ℃ was measured in the range of 25 ℃ to 200 ℃. In addition, among the results obtained by the above measurement, the storage modulus (E) was measured _A ) And loss of elastic modulus (E) _B ) Ratio of (E) _B /E _A ) The temperature at which the value of (A) reaches the maximum value is taken as the glass transition temperature. The results are shown in tables 1 and 3.

(evaluation of moisture permeability)

An adhesive layer-attached film was prepared in which an acrylic adhesive layer 1 having a thickness of 5 μm was formed on the surface of a triacetyl cellulose film having a thickness of 20 μm. The film with an adhesive layer has a moisture permeability of 5200[ g/(m) at a temperature of 80 ℃ and a relative humidity of 90% ² ·24hr)]。

After the adhesive 1 was applied to the surface of the acrylic pressure-sensitive adhesive layer 1, the coated layer was cured by irradiation with ultraviolet rays to form a 30 μm adhesive layer 1, and a laminate having a laminated structure of a triacetyl cellulose film having an acrylic pressure-sensitive adhesive layer 1/20 μm of an adhesive layer 1/5 μm of 30 μm was obtained.

The obtained laminate was measured for moisture permeability [ g/(m) at a temperature of 40 ℃ and a relative humidity of 90%, by the cup method prescribed in JIS Z0208 ² 24hr) ]. Bonding agentThe number 1 was changed to 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)

The components shown in table 1 were mixed in the mixing ratios (unit is part by mass) shown in table 1, and then deaerated to prepare active energy ray-curable adhesive compositions (adhesives 1 to 2). The cationic polymerization initiator (B-1) was added in the form of a 50% propylene carbonate solution, and the amount of the solid content thereof is shown in table 1.

[ TABLE 1]

(cationically polymerizable Compound (A))

A-1: 3, 4-epoxycyclohexanecarboxylic acid 3 ', 4' -epoxycyclohexylmethyl ester (trade name: CEL2021P, manufactured by Daicel K.K.)

A-2: 1, 2-epoxy-4- (2-epoxyethyl) cyclohexane adduct of 2, 2-bis (hydroxymethyl) -1-butanol (trade name: EHPE3150, manufactured by Daicel K.K.)

A-3: neopentyl glycol diglycidyl ether (trade name: EX-211L, manufactured by Nagase ChemteX)

A-4: 3-Ethyl-3- { [ (3-ethyloxetan-3-yl) methoxy ] methyl } oxetane (trade name: OXT-221, manufactured by Toyo Seisaku-sho Co., Ltd.)

A-5: bisphenol A type epoxy resin (trade name: EP-4100E, ADEKA, manufactured by K.K., viscosity 13 Pa.s (temperature 25 ℃ C.))

A-6: aromatic oxetane compound (trade name: TCM-104, manufactured by TRONLY)

(photo cation polymerization initiator (B))

B-1: CPI-100P, a 50% by mass solution manufactured by San-Apro Co., Ltd

(photosensitive auxiliary (C))

C-1: 1, 4-diethoxynaphthalenes

(production of Linear polarizing plate 1)

A polyvinyl alcohol film having a thickness of 20 μm, a polymerization degree of 2, 400 and a saponification degree of 99.9% or more was uniaxially stretched at a stretch ratio of 4.5 times on a roll heated to 125 ℃ and immersed in water at 28 ℃ for 30 seconds while being kept under tension, and then immersed in a 28 ℃ dyeing bath 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.

Next, the resultant was immersed in an aqueous boric acid solution 1 at 64 ℃ 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.

Next, the resultant was immersed in an aqueous boric acid solution 2 at 67 ℃ 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, the polarizing film was washed with pure water at 10 ℃ and dried at 80 ℃.

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 laminated on one surface of the obtained polarizing film via a water-based adhesive, and dried at 90 ℃.

(production of Linear polarizing plate 2)

A linear polarizing plate 2 having a laminated structure of COP film/water-based adhesive (adhesive layer)/polarizer was obtained 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.

(preparation of a.lambda./2 retardation layer)

An alignment film coating liquid was applied to a transparent resin substrate and dried, thereby carrying out a λ/2 alignment treatment. Next, a coating liquid containing a discotic liquid crystalline compound was applied to the alignment surface, and heating and UV irradiation were performed to fix the alignment of the liquid crystalline compound, thereby producing a retardation-developing layer having a thickness of 2 μm on the transparent resin substrate.

(production of a.lambda./4 retardation layer)

A coating liquid containing a rod-like polymerizable nematic liquid crystal monomer was applied to a transparent resin substrate for λ/4 alignment which had been subjected to a rubbing treatment on an alignment film, and the coating liquid was cured while maintaining the refractive index anisotropy, thereby obtaining a phase difference-developing layer having a thickness of 1 μm on the transparent resin substrate.

(production of retardation layer laminate)

The liquid crystal layer side of the lambda/2 phase difference layer and the lambda/4 phase difference layer was subjected to corona treatment. The retardation layers were arranged 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 became 60 °, and the liquid crystal layers were bonded to each other with a laminator using an adhesive 1 so that the adhesive thickness became 3 μm, to obtain a laminate.

An ultraviolet irradiation device (manufactured by Fusion UV Systems Co., Ltd.) was used to irradiate the sample with a cumulative light amount of 400mJ/cm ² (UV-B) the resulting laminate was irradiated with ultraviolet light from the lambda/4 retardation layer side, and the adhesive 1 was cured to give a2 nd cured product layer, thereby obtaining a retardation layer laminate having a laminate structure of "lambda/2 retardation layer" (1 st retardation layer)/adhesive layer (2 nd cured product layer)/"lambda/4 retardation layer" (2 nd retardation layer).

< example 1>

The alignment film on the λ/2 retardation layer side of the obtained retardation layer laminate and the transparent resin substrate were peeled off, and the surface of the linear polarizing plate 1 opposite to the thermoplastic resin film was bonded to the liquid crystal layer of the λ/2 retardation layer using the adhesive 2. The thickness of the 1 st cured product layer formed from the adhesive 2 was 3 μm, and the angle formed between the transmission axis of the polarizing plate 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 substrate were peeled off to obtain a laminate having a laminate structure of thermoplastic resin film/aqueous adhesive (adhesive layer)/polarizing plate/1 st cured product layer/"λ/2 retardation layer" (1 st retardation layer)/2 nd cured product layer/"λ/4 retardation layer" (2 nd retardation layer). An acrylic pressure-sensitive adhesive layer 1 having a thickness of 15 μm was laminated on the surface of the 2 nd retardation layer of the laminate thus obtained, to obtain a laminate of example 1. The obtained laminate was evaluated for metal corrosion resistance, iodine amount 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 of the obtained retardation layer laminate was peeled off from the transparent resin substrate, and the surface of the linear polarizing plate 1 opposite to the thermoplastic resin film was bonded to the liquid crystal layer of the λ/2 retardation layer using an acrylic pressure-sensitive adhesive layer 2 having a thickness of 5 μm (storage modulus at 80 ℃ C. of 0.5MPa, glass transition temperature-45 ℃ C.). The angle formed by the transmission axis of the polarizing plate 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 substrate were peeled off to obtain a laminate having a laminate structure of thermoplastic resin film/aqueous adhesive (adhesive layer)/polarizing plate/adhesive layer/"λ/2 retardation layer" (1 st retardation layer)/2 nd cured layer/"λ/4 retardation layer" (2 nd retardation layer). An acrylic pressure-sensitive adhesive layer 1 having a thickness of 15 μm was laminated on the surface of the 2 nd retardation layer of the laminate thus obtained, to obtain a laminate of comparative example 1. The obtained laminate was evaluated for metal corrosion resistance, iodine amount in the pressure-sensitive adhesive layer, and adhesion. The results are shown in Table 2.

[ TABLE 2]

	Example 1	Comparative example 1
			1 st cured product layer	Adhesive	2	Adhesive 2
Linear polarizing plate	Polarizing plate	1					Polarizing plate 2
			Layer of No. 2 cured product	Adhesive	1	Adhesive 1
Resistance to metal corrosion	◎	×
			Amount of iodine (mg/kg) in the adhesive layer	310	950
Adhesion Property	△	○

(preparation of active energy ray-curable adhesive composition)

The components shown in table 3 were mixed at the mixing ratios (unit is parts by mass) shown in table 3, and then deaerated to prepare active energy ray-curable adhesive compositions (adhesives 3 to 5). The cationic polymerization initiator (B-2) was added in the form of a 50% propylene carbonate solution, and the amount of the solid content thereof is shown in table 3.

[ TABLE 3]

(cationically polymerizable Compound (A))

A-7: 3, 4-epoxycyclohexanecarboxylic acid 3 ', 4' -epoxycyclohexylmethyl ester (trade name: CEL2021P, manufactured by Daicel K.K.)

A-8: 1, 2-epoxy-4- (2-epoxyethyl) cyclohexane adduct of 2, 2-bis (hydroxymethyl) -1-butanol (trade name: EHPE3150, manufactured by Daicel K.K.)

A-9: neopentyl glycol diglycidyl ether (trade name: ED-523T, manufactured by ADEKA K.K.)

A-10: 3-Ethyl-3- { [ (3-ethyloxetan-3-yl) methoxy ] methyl } oxetane (trade name: OXT-221, manufactured by Toyo Seisaku-sho Co., Ltd.)

A-11: a compound represented by the following formula

[ chemical formula 7 ]

(photo cation polymerization initiator (B))

B-2: CPI-100P, available from San-Apro corporation, 50% by mass solution

(photosensitive auxiliary (C))

C-2: 1, 4-diethoxynaphthalenes

< 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 had a laminate structure of a thermoplastic resin film/an aqueous adhesive (adhesive layer)/a polarizing plate/a 1 st cured product layer (cured product layer of adhesive 3)/"λ/2 retardation layer" (1 st retardation layer)/a 2 nd cured product layer (cured product layer of adhesive 1)/"λ/4 retardation layer" (2 nd retardation layer)/15 μm pressure-sensitive adhesive layer.

The laminate of example 3 had a laminate structure of a thermoplastic resin film/an aqueous adhesive (adhesive layer)/a polarizing plate/a 1 st cured product layer (cured product layer of adhesive 4)/"a/2 phase difference layer" (1 st phase difference layer)/a 2 nd cured product layer (cured product layer of adhesive 1)/"a/4 phase difference layer" (2 nd phase difference layer)/15 μm adhesive layer.

The laminate of example 4 had a laminate structure of a thermoplastic resin film/an aqueous adhesive (adhesive layer)/a polarizing plate/a 1 st cured product layer (cured product layer of adhesive 5)/"λ/2 retardation layer" (1 st retardation layer)/a 2 nd cured product layer (cured product layer of adhesive 1)/"λ/4 retardation layer" (2 nd retardation layer)/15 μm 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, iodine amount in the pressure-sensitive adhesive layer, and adhesion. The results are shown in Table 4.

The laminate of comparative example 2 had a laminate structure of a thermoplastic resin film/an aqueous adhesive (adhesive layer)/a polarizing plate/a 1 st cured product layer (cured product layer of adhesive 1)/"λ/2 retardation layer" (1 st retardation layer)/a 2 nd cured product layer (cured product layer of adhesive 1)/"λ/4 retardation layer" (2 nd retardation layer)/15 μm pressure-sensitive adhesive layer.

[ TABLE 4]

	Example 2	Example 3	Example 4	Comparative example 2
					1 st cured product layer	Adhesive	3	Adhesive 4	Adhesive 5	Adhesive 1
Linear polarizing plate	Polarizing plate	1	Polarizing plate 1	Polarizing plate 1							Polarizing plate 1
					Layer of No. 2 cured product	Adhesive	1	Adhesive 1	Adhesive 1	Adhesive 1
Resistance to metal corrosion	◎	○	○	×
					Amount of iodine (mg/kg) in the adhesive layer	340	370	420	1050
Adhesion Property	○	○	○	○

Description of the reference numerals

10: linear polarizing plate, 11: thermoplastic resin film, 12: adhesive layer, 13: polarizing plate, 14: 1 st cured product layer, 20: phase difference layer, 30: 1 st retardation layer, 31: phase difference developing layer, 32: alignment layer, 33: substrate layer, 40: phase difference layer 2, 41: substrate layer, 42: alignment layer, 43: phase difference developing layer, 50: cured 2 layer, 60: phase difference laminate, 70: adhesive layer, 80: optical laminate, 100: an optical laminate.

Claims

1. An optical laminate comprising a polarizing plate, a1 st cured product layer, a phase difference layer and an adhesive layer in this order,

the polarizing plate is formed of a polyvinyl alcohol resin containing iodine,

the retardation layer comprises at least one retardation-developing layer which is a polymer of a polymerizable liquid crystal compound,

the iodine content of the pressure-sensitive adhesive layer after the optical laminate is stored at a temperature of 80 ℃ and a relative humidity of 90% for 250 hours is 900mg/kg or less,

the polarizer is in direct contact with the 1 st cured layer,

the 1 st cured layer is in direct contact with the phase difference layer.

2. The optical laminate according to claim 1, wherein the retardation layer is a layer comprising a1 st polymerization layer, a2 nd curing layer and a2 nd polymerization layer in this order from the 1 st curing layer side,

the 1 st and 2 nd polymeric layers each independently comprise a polymer of a polymerizable liquid crystal compound.

3. The optical stack of claim 2, wherein the 2 nd cured layer is an active energy ray cured layer.

4. The optical laminate of any one of claims 1 to 3, wherein the 1 st cured layer at a thickness of 30 μm isThe water vapor permeability at the temperature of 80 ℃ and the relative humidity of 90 percent is 1500 g/(m) ² 24hr) or less.

5. An optical laminate comprising a polarizing plate, a1 st cured product layer, a1 st retardation layer, a2 nd cured product layer, a2 nd retardation layer and an adhesive layer in this order,

the polarizing plate is formed of a polyvinyl alcohol resin containing iodine,

the 1 st cured product layer has a storage modulus of 300MPa or more at a temperature of 80 ℃,

the polarizer is in direct contact with the 1 st cured layer,

the 1 st cured layer is in direct contact with the 1 st phase difference layer.

6. The optical stack of claim 5, wherein the 2 nd cured layer has a storage modulus at a temperature of 80 ℃ of 20MPa or greater.

7. The optical stack of claim 5 or 6 wherein the 1 st cured layer has a storage modulus E at a temperature of 80 ℃ ₁ Greater than the storage modulus E of the 2 nd cured product layer at a temperature of 80 DEG C ₂ 。

8. The optical laminate according to any one of claims 5 to 7, wherein the first cured product layer 1 having a thickness of 30 μm has a moisture permeability of 1500 g/(m) at a temperature of 80 ℃ and a relative humidity of 90% ² 24hr) or less.

9. An optical laminate comprising a polarizing plate, a1 st cured product layer, a1 st retardation layer, a2 nd cured product layer, a2 nd retardation layer and an adhesive layer in this order,

the polarizing plate is formed of a polyvinyl alcohol resin containing iodine,

the 1 st retardation layer and the 2 nd retardation layer each independently comprise a retardation-developing layer which is a polymer of a polymerizable liquid crystal compound,

glass transition temperature Tg of the 1 st cured layer ₁ More than 60 ℃ of the total weight of the composition,

the polarizer is in direct contact with the 1 st cured layer,

the 1 st cured layer is in direct contact with the 1 st phase difference layer.

10. The optical stack of claim 9, wherein the 2 nd cured layer has a glass transition temperature Tg ₂ Is above 40 ℃.

11. The optical stack of claim 9 or 10, wherein the glass transition temperature Tg of the 1 st cured layer ₁ Greater than the glass transition temperature Tg of the 2 nd cured layer ₂ 。

12. The optical laminate according to any one of claims 9 to 11, wherein the first cured product layer 1 having a thickness of 30 μm has a moisture permeability of 1500 g/(m) at a temperature of 80 ℃ and a relative humidity of 90% ² 24hr) or less.

13. An optical laminate comprising a polarizing plate, a1 st cured product layer, a phase difference layer and an adhesive layer in this order,

the polarizing plate is formed of a polyvinyl alcohol resin containing iodine,

the phase difference layer comprises a phase difference-developing layer comprising a polymer of a polymerizable liquid crystal compound,

the active energy ray-curable composition is a composition containing an epoxy compound A2-1, wherein the epoxy compound A2-1 contains A3-ring fused ring and 2 glycidyl ether groups in the molecule.

14. An optical laminate comprising a polarizing plate, a1 st cured product layer, a1 st retardation layer, a2 nd cured product layer, a2 nd retardation layer and an adhesive layer in this order,

the polarizing plate is formed of a polyvinyl alcohol resin containing iodine,

15. An active energy ray-curable composition comprising 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 A3-ring fused ring and a diglycidyl ether group in the molecule,

the content of the polyfunctional oxetane compound A5-1 was more than that of the epoxy compound A2-1 containing A3-ring type condensed ring and 2 glycidyl ether groups in the molecule.

16. The active energy ray-curable composition according to claim 15, wherein a content ratio of the polyfunctional oxetane compound a5-1 to the epoxy compound a2-1 containing A3-ring fused ring and 2 glycidyl ether groups in a molecule is, in terms of a mass ratio, 1.5/1 to 5/1 of the polyfunctional oxetane compound a 5-1/the epoxy compound a2-1 containing A3-ring fused ring and 2 glycidyl ether groups in a molecule.