CN114868051A

CN114868051A - Laminated body

Info

Publication number: CN114868051A
Application number: CN202080089776.9A
Authority: CN
Inventors: 永安智
Original assignee: Sumitomo Chemical Co Ltd
Current assignee: Sumitomo Chemical Co Ltd
Priority date: 2019-12-26
Filing date: 2020-12-22
Publication date: 2022-08-05
Also published as: WO2021132234A1; JP2021105713A; TW202134061A; KR20220122694A

Abstract

The invention provides a laminate which comprises a polarizing film and a phase difference layer, has good adhesion between the polarizing film and the phase difference layer, and has excellent durability. A laminate comprising a polarizing film, a1 st cured product layer and a1 st retardation layer laminated in this order, wherein the 1 st cured product layer comprises a cured product of a1 st active energy ray-curable composition, the 1 st active energy ray-curable composition contains (A) a cationically polymerizable compound and (B) a photocationic polymerization initiator, the 1 st active energy ray-curable composition contains the (B) photocationic polymerization initiator in an amount of 1 to 10 parts by mass based on 100 parts by mass of the cationically polymerizable compound (A), and the cationically polymerizable compound (A) contains an oxetane compound in an amount of 45% by mass or more based on the total mass of the cationically polymerizable compound (A).

Description

Laminated body

Technical Field

The present invention relates to a laminate, and further relates to an image display device including the 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 laminate composed of a polarizing film and a retardation layer is known. Patent document 1 proposes a laminate in which a polarizing film and a retardation layer are bonded to each other through an adhesive layer made of an active energy ray-curable adhesive composition.

Documents of the prior art

Patent document

Patent document 1: international publication No. 2017/183333

Disclosure of Invention

Problems to be solved by the invention

In the laminate proposed in patent document 1, the adhesion between the polarizing film and the retardation layer is not sufficient, and the durability is not satisfactory.

The purpose of the present invention is to provide a laminate which comprises a polarizing film and a phase difference layer, and which has good adhesion between the polarizing film and the phase difference layer and excellent durability.

Means for solving the problems

The present invention provides the following [1] to [20 ].

[1] A laminate comprising a polarizing film, a1 st cured product layer and a1 st retardation layer laminated in this order, wherein the thickness of the 1 st retardation layer is 10 [ mu ] m or less, the 1 st cured product layer comprises a cured product of a1 st active energy ray-curable composition,

the 1 st active energy ray-curable composition contains (A) a cationically polymerizable compound and (B) a photocationic polymerization initiator, and

the cationic photopolymerization initiator (B) is contained in an amount of 1 to 10 parts by mass based on 100 parts by mass of the cationic polymerizable compound (A),

the cationically polymerizable compound (a) contains not less than 45% by mass of an oxetane compound based on the total mass of the cationically polymerizable compound (a).

[2] The laminate according to [1], wherein the 1 st active energy ray-curable composition contains 0.1 to 3.0 parts by mass of (C) a photosensitizer exhibiting maximum absorption at a wavelength of more than 400nm, based on 100 parts by mass of the cationically polymerizable compound (A),

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

(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. )

[3] The laminate according to [1] or [2], wherein the oxetane compound is at least one selected from the group consisting of 3-ethyl-3-hydroxymethyloxetane, xylylene dioxirane, 3-ethyl-3- (phenoxymethyl) oxetane, 3-ethyl-3- { [ (3-ethyloxetan-3-yl) methoxy ] methyl } oxetane, 3-ethyl-3- (2-ethylhexyloxymethyl) oxetane and 3-ethyl-3- (cyclohexyloxymethyl) oxetane.

[4] The laminate according to any one of [1] to [3], wherein the cationically polymerizable compound (A) contains an alicyclic epoxy compound in an amount of 10 to 50 mass% based on the total mass of the cationically polymerizable compound (A).

[5] The laminate according to any one of [1] to [4], wherein the photo-cationic polymerization initiator (B) is at least one ionic compound selected from aromatic sulfonium salts and aromatic iodonium salts.

[6] The laminate according to any one of [1] to [5], wherein the viscosity of the 1 st active energy ray-curable composition at 25 ℃ is 200 mPas or less.

[7] The laminate according to any one of [1] to [6], wherein the 1 st active energy ray-curable composition satisfies the following formula (1),

(J _A /J _B )×100≥60(％) (1)

[J _A represents: an amount of heat (unit: mJ/g) measured by a differential scanning calorimeter when ultraviolet rays having a peak at a wavelength of 365nm are irradiated to a1 st active energy ray-curable composition through a substrate having 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,

J _B represents: the heat quantity (mJ/g) measured by a differential scanning calorimeter when ultraviolet rays having a peak at a wavelength of 365nm are irradiated to the 1 st active energy ray-curable composition without passing through the substrate.]

[8] The laminate according to any one of [1] to [7], wherein the 1 st cured product layer has a storage modulus at 80 ℃ of 300MPa or more.

[9] The laminate according to any one of [1] to [8], wherein the thickness of the 1 st cured product layer is 0.5 μm or more and 10 μm or less.

[10] The laminate according to any one of [1] to [9], wherein the 1 st retardation layer has a light transmittance of 0% or more and 50% or less at a wavelength of 380nm and a light transmittance of 30% or more at a wavelength of 400 nm.

[11] The laminate according to any one of [1] to [10], wherein the 1 st retardation layer has a light transmittance of 0% or more and 10% or less at a wavelength of 380nm and a light transmittance of 30% or more at a wavelength of 400 nm.

[12] The laminate according to any one of [1] to [11], wherein a2 nd cured product layer and a2 nd cured product layer are sequentially laminated on the 1 st phase difference layer on the opposite side of the 1 st cured product layer,

the 2 nd cured product layer contains a cured product of a2 nd active energy ray-curable composition, and at least one of the 1 st retardation layer and the 2 nd retardation layer has a light transmittance of 0% or more and 10% or less at a wavelength of 380nm and a light transmittance of 30% or more at a wavelength of 400 nm.

[13] The laminate according to [12], wherein the 1 st retardation layer is an 1/2-wavelength retardation layer, and the 2 nd retardation layer is an 1/4-wavelength retardation layer.

[14] The laminate according to [12], wherein the 1 st retardation layer is an 1/2 wavelength retardation layer or a 1/4 wavelength retardation layer, and the 2 nd retardation layer is a positive C-plate.

[15] The laminate according to any one of [12] to [14], wherein at least one of the 1 st retardation layer and the 2 nd retardation layer includes a liquid crystal layer exhibiting retardation.

[16] The laminate according to any one of [12] to [15], wherein the thickness of at least one of the 1 st retardation layer and the 2 nd retardation layer is 0.5 μm or more and 50 μm or less.

[17] A circularly polarizing plate comprising the laminate according to any one of [1] to [16 ].

[18] An image display device comprising an image display panel and the laminate according to any one of [1] to [17] disposed on a viewing side of the image display panel.

[19] The image display device according to item [18], wherein the laminate is disposed in an orientation in which the polarizing film is positioned on a viewing side.

[20] An organic electroluminescent display device comprising the image display device of [18] or [19 ].

Effects of the invention

According to the present invention, a laminate having a polarizing film and a phase difference layer, which has good adhesion between the polarizing film and the phase difference layer and excellent durability, can be provided.

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 sectional view schematically showing a laminate of the present invention.

FIG. 4 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.

< layered product >

The laminate of the present invention is described with reference to fig. 1. The laminate 100 shown in fig. 1 includes a polarizing film 11, a1 st cured product layer 12, and a1 st retardation layer 13 laminated in this order.

The thickness of the laminate 100 may be, for example, 3 μm or more and 100 μm or less, and is preferably 3 μm or more and 60 μm or less.

The laminate 100 may be long or may be a single sheet. When the laminate 100 is in a single sheet shape, the shape of the laminate 100 in a plan view may be substantially rectangular. The planar view is a view from the thickness direction of the 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 laminate 100 is not particularly limited. When the 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.

(polarizing film)

The polarizing film 11 may be an absorption-type polarizing plate having a property of absorbing linearly polarized light having a vibration plane parallel to an absorption axis thereof and transmitting linearly polarized light having a vibration plane orthogonal to the absorption axis (parallel to a transmission axis). As the polarizing film 11, 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 film 11 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 material film is not particularly limited, and for example, a material film of 5 μm to 35 μm is preferably used so that the thickness of the polarizing plate is 15 μm or less. More preferably 20 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 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 film 11 is usually 30 μm or less, preferably 28 μm or less, more preferably 20 μm or less, still more preferably 15 μm or less, and particularly preferably 10 μm or less. The thickness of the polarizing film 11 is usually 2 μm or more, preferably 3 μm or more.

As the polarizing film 11, for example, as described in japanese patent application laid-open No. 2016 and 170368, a film in which a dichroic dye is aligned in a cured film obtained by polymerizing a liquid crystal compound may be used.

As the dichroic dye, a dichroic dye having absorption in a wavelength range of 380nm to 800nm can be used, and an organic dye is preferably used. Examples of the dichroic dye include azo compounds. The liquid crystal compound is a liquid crystal compound capable of polymerizing while maintaining alignment, and may have a polymerizable group in a molecule. Further, as described in WO2011/024891, the polarizing plate may be formed of a dichroic dye having liquid crystallinity.

(1 st cured product layer)

The 1 st cured product layer 12 is disposed between the polarizing film 11 and the 1 st phase difference layer 13 in order to bond the polarizing film 11 and the 1 st phase difference layer 13. The 1 st cured product layer 12 contains a cured product of a1 st active energy ray-curable composition. The 1 st cured product layer 12 tends to easily obtain good durability and adhesion by a cured product containing the 1 st active energy ray-curable composition. In the present invention, the evaluation of durability and adhesion was performed according to the method described in the section of examples described later.

The thickness of the 1 st cured product layer 12 may be, for example, 10 μm or less, preferably 8 μm or less, more preferably 7 μm or less, further preferably 6 μm or less, and particularly preferably 4 μm or less. The thickness of the 1 st cured product layer 12 is, for example, 0.5 μm or more, preferably 1 μm or more, and more preferably 2 μm or more.

(1 st active energy ray-curable composition)

The 1 st active energy ray-curable composition is a cationically polymerizable composition which is cured by irradiation with an active energy ray. The 1 st active energy ray-curable composition contains 1 to 10 parts by mass of a photo cationic polymerization initiator (B) and 100 parts by mass of a cationically polymerizable compound (a) per 100 parts by mass of the cationically polymerizable compound (a). The 1 st active energy ray-curable composition preferably further contains 0.1 to 3.0 parts by mass of a photosensitizer (C) exhibiting a maximum absorption at a wavelength of more than 400nm, based on 100 parts by mass of the cationically polymerizable compound (a).

(cationically polymerizable Compound (A))

The cationically polymerizable compound (a) is a component which can be cured by cationic polymerization upon irradiation with active energy rays. The adhesive strength is developed by polymerization and curing of the cationically polymerizable compound (a). The cationically polymerizable compound (a) contains not less than 45 mass% of the oxetane compound (a1) based on the total mass of the cationically polymerizable compound (a). When the oxetane compound (a1) is contained in an amount of 45 mass% or more in the 1 st active energy ray-curable composition, the viscosity of the active energy ray-curable composition is lowered, and therefore, the application of a thin film is easily performed, the elastic modulus of a cured product is improved, and good durability is easily obtained.

(Oxetane Compound (A1))

In the present specification, the oxetane compound (a1) is a compound having an oxetanyl group, and may be an aliphatic compound, an alicyclic compound or an aromatic compound. The oxetane compound (a1) referred to in the present specification is a compound having no epoxy group.

The oxetane compound (a1) may be a monofunctional oxetane compound having only 1 oxetanyl group, or may be a polyfunctional oxetane compound having 2 or more oxetanyl groups. The oxetane compound (A1) is preferably a polyfunctional oxetane compound, preferably a 2-functional oxetane compound having 2 oxetanyl groups.

Specific examples of the oxetane compound (A1) 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, 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 (a1), 1 kind of oxetane compound may be used alone, or a plurality of different kinds may be used in combination. Among them, at least one selected from the group consisting of 3-ethyl-3-hydroxymethyloxetane, xylylene-dioxy-oxetane, 3-ethyl-3- (phenoxymethyl) oxetane, 3-ethyl-3- { [ (3-ethyloxetan-3-yl) methoxy ] methyl } oxetane, 3-ethyl-3- (2-ethylhexyloxymethyl) oxetane and 3-ethyl-3- (cyclohexyloxymethyl) oxetane is preferable.

The Oxetane compound (a1) can be used as a commercially available product, and examples thereof include "Aron Oxetane (registered trademark)" series sold by east asian synthesis (trade name) and "etenacoll (registered trademark)" series sold by yushu hseng (trade name) strain.

The content of the oxetane compound (a1) in the cationically polymerizable compound (a) is 45 mass% or more, preferably 50 mass% or more, more preferably 55 mass% or more, and further preferably 60 mass% or more based on the total mass of the cationically polymerizable compound (a). The content of the oxetane compound (a1) in the cationically polymerizable compound (a) is, for example, 90 mass% or less, preferably 80 mass% or less, and more preferably 75 mass% or less. When the content of the oxetane compound (a1) is 90% by mass or less, the adhesion tends to be less likely to decrease.

When the oxetane compound (a1) contains a polyfunctional oxetane compound and a monofunctional oxetane compound, the polyfunctional oxetane compound is contained preferably at 50 mass% or more, more preferably at 60 mass% or more, and further preferably at 70 mass% or more based on the total mass of the oxetane compound (a 1).

(other cationically polymerizable Compound)

The cationically polymerizable compound (a) may further include at least one selected from the group consisting of an alicyclic epoxy compound (a2), an aliphatic epoxy compound (A3), and an aromatic epoxy compound (a 4).

When the cationically polymerizable compound (a) contains the alicyclic epoxy compound (a2), the content of the alicyclic epoxy compound (a2) is, for example, 10 parts by mass or more and 50 parts by mass or less, preferably 10 parts by mass or more and 40 parts by mass or less, more preferably 10 parts by mass or more and 35 parts by mass or less, and further preferably 10 parts by mass or more and 30 parts by mass or less with respect to 100 parts by mass of the cationically polymerizable compound (a). When the content of the alicyclic epoxy compound (a2) is 10 parts by mass or more, the curing rate of the cationically polymerizable compound tends to be low. When the content of the alicyclic epoxy compound (a2) is 50 parts by mass or less, the viscosity of the cationically polymerizable compound tends to be inhibited from increasing, and the film coating tends to be easily performed.

When the cationically polymerizable compound (a) contains the aliphatic epoxy compound (A3), the content of the aliphatic epoxy compound (A3) may be, for example, 1 part by mass or more and 50 parts by mass or less with respect to 100 parts by mass of the cationically polymerizable compound (a), and is preferably 2.5 parts by mass or more and 40 parts by mass or less, and more preferably 5 parts by mass or more and 30 parts by mass or less from the viewpoint of adhesion.

When the cationically polymerizable compound (a) contains the aromatic epoxy compound (a4), the content of the aromatic epoxy compound (a4) is, for example, 10 parts by mass or more and 50 parts by mass or less, preferably 15 parts by mass or more and 40 parts by mass or less, and more preferably 20 parts by mass or more and 30 parts by mass or less with respect to 100 parts by mass of the cationically polymerizable compound (a). When the content of the aromatic epoxy compound (a4) is 50 parts by mass or less, the adhesion tends to be less likely to decrease.

By using the oxetane compound (a1) in combination with the alicyclic epoxy compound (a2), the curing speed of the cationically polymerizable compound (a) is increased. The ratio of the oxetane compound (A1) to the alicyclic epoxy compound (A2) is 4: 1 to 1: 1, more preferably 3: 1 to 1: 1, and still more preferably 2: 1 to 1: 1. When the amount is within the above range, the curing can be efficiently performed, and the obtained cured product has a dense crosslinked structure.

The 1 st active energy ray-curable composition preferably contains no solvent. Hereinafter, each component will be described in detail

(alicyclic epoxy Compound (A2))

The alicyclic epoxy compound (a2) is a compound having 1 or more alicyclic epoxy groups.

The alicyclic epoxy compound (a2) 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).

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 a group having 1 or more hydrogen atoms is bonded to another chemical structure may be an alicyclic epoxy compound(A2)。(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 1 st active energy ray-curable composition can be adjusted by the alicyclic epoxy compound (a 2).

Specific examples of the alicyclic epoxy compound (A2) include 3, 4-epoxycyclohexanecarboxylic acid 3, 4-epoxycyclohexylmethyl ester, 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 (a2), 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 (a2), 1 kind of alicyclic epoxy compound may be used alone, or a plurality of different alicyclic epoxy compounds may be used in combination.

Examples of the alicyclic epoxy compound (a2) include commercially available products such as "Celoxide (registered trademark)" series sold by DAICEL (strain) and "EHPE 3150", "Cyclomer (registered trademark)", and "Cyracure UVR" series sold by DOW Chemical company.

In the present invention, the aliphatic epoxy compound (A3) includes a monofunctional aliphatic epoxy (A3-1) which is a compound having 1 epoxy group, and a polyfunctional aliphatic epoxy (A3-2) having 2 or more epoxy groups. From the viewpoint of maintaining the cohesive force of the cured product and improving the adhesion, a polyfunctional aliphatic epoxy is preferable.

The monofunctional aliphatic epoxy (A3-1) can adjust the viscosity of the 1 st active energy ray-curable composition.

Examples of the monofunctional aliphatic epoxy (A3-1) include glycidyl etherate of aliphatic alcohol, glycidyl ester of alkyl carboxylic acid, etc., and specific examples thereof include allyl glycidyl ether, butyl glycidyl ether, sec-butyl phenyl glycidyl ether, 2-ethylhexyl glycidyl ether, C12 and C13 mixed alkyl glycidyl ether, glycidyl ether of alcohol, monoglycidyl ether of aliphatic higher alcohol, glycidyl ester of higher fatty acid, etc. As the monofunctional aliphatic epoxy (A3-1), 1 type of monofunctional epoxy compound may be used alone, or a plurality of different types may be used in combination.

The polyfunctional aliphatic epoxy (A3-2) is a compound having 2 or more epoxy groups and no aromatic ring. However, the polyfunctional aliphatic epoxy (A3-2) mentioned in the present specification does not include a compound having an alicyclic epoxy group contained in the alicyclic epoxy compound (A2). The adhesiveness of the cured adhesive layer can be adjusted by the polyfunctional aliphatic epoxy (A3-2).

The polyfunctional aliphatic epoxy (A3-2) is more preferably an aliphatic diepoxy compound represented by the following formula (b). By including an aliphatic diepoxy compound represented by the following formula (b) as the polyfunctional aliphatic epoxy compound (a3), an active energy ray-curable adhesive having low viscosity and easy application can be obtained.

In the formula (b), Z is C1-9 alkylene group, C3 or C4 alkylidene group, C2 alicyclic hydrocarbon group, or-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-with m and n each independently representing an integer of 1 or more and with the sum of m and n being 9 or less.

The 2-valent alicyclic hydrocarbon group may be, for example, a 2-valent alicyclic hydrocarbon group having 4 to 8 carbon atoms, and examples thereof include a 2-valent group represented by the following formula (b-1).

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 and cyclohexanedimethanol.

From the viewpoint of obtaining a1 st active energy ray-curable composition which has a low viscosity and is easy to apply, 1, 4-butanediol diglycidyl ether, 1, 6-hexanediol diglycidyl ether, and neopentyl glycol diglycidyl ether are preferable. As the aliphatic epoxy compound (a3), 1 kind of aliphatic epoxy compound may be used alone, or a plurality of different aliphatic epoxy compounds may be used in combination.

As the aliphatic epoxy compound (A3), commercially available compounds can be used, and examples thereof include "EP-4088S", "ED-523T" (manufactured by ADEKA, Inc., supra), "EX-211L" and "EX-212L" (manufactured by Nagase ChemteX, Inc., supra).

Aromatic epoxy Compound (A4)

The aromatic epoxy compound (A4) contains a monofunctional aromatic epoxy (A4-1) which is a compound having 1 epoxy group, and a polyfunctional aromatic epoxy (A4-2) having 2 or more epoxy groups. However, the aromatic epoxy compound (a4) referred to in the present invention does not include a compound having an alicyclic epoxy group in the molecule, which is contained in the alicyclic epoxy compound (a 2).

Examples of the monofunctional aromatic epoxy compound (A4-1) 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, or catechol; monoglycidyl etherate of an 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.

As the monofunctional aromatic epoxy compound (A4-1), commercially available compounds can be used, and examples thereof include "EX-142", "EX-146", EX-147 "and" EX-121 "(both of which are manufactured by Nagase ChemteX).

Specific examples of the polyfunctional aromatic epoxy (A4-2) 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. The polyfunctional aromatic epoxy compound (a5) may be used alone or in combination of two or more.

As the polyfunctional aromatic epoxy (A4-2), commercially available products can be used, and examples thereof include "DENACOL EX-201", "DENACOL EX-711" and "DENACOL EX-721" (both of which are manufactured by Nagase ChemteX, Inc.); "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 manufactured by DIC corporation); "jER 828" and "jER 828 EL" (both manufactured by Mitsubishi chemical corporation); "ADEKA RESIN EP-4100", "ADEKA RESIN EP-4100G", "ADEKA RESIN EP-4100E", "ADEKA RESIN 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 the above, manufactured by ADEKA, Inc.), etc.

In order to make the 1 st active energy ray-curable composition solvent-free, it is preferable to use the curable components [ oxetane compound (a1), alicyclic epoxy compound (a2), aliphatic epoxy compound (A3), and aromatic epoxy compound (a4) ] which are not diluted 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 the 1 st active energy ray-curable 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 cationically polymerizable compound (a) contained in the 1 st active energy ray-curable composition is not limited to the above-mentioned curable component, and may include a cationically polymerizable curable component other than the above-mentioned cationically polymerizable curable component and a radically polymerizable curable component. Examples of the radical polymerizable curable component include acrylic compounds.

However, since radical polymerization tends to cause large curing shrinkage, the 1 st active energy ray-curable composition preferably contains only a cationically polymerizable curable component as the cationically polymerizable compound (a).

(photo cation polymerization initiator (B))

The 1 st active energy ray-curable composition contains the photo cationic polymerization initiator (B), and can form the adhesive layer by curing the cationically polymerizable compound (a) by cationic polymerization by irradiation with an active energy ray.

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, when the amount is increased, the ionic substance in the cured product increases, and thus the hygroscopicity of the cured product increases, and there is a possibility that the durability of the laminate is deteriorated, and therefore, the amount of the photo cationic polymerization initiator (B) is 10 parts by mass or less with respect to 100 parts by mass of the total amount of the cationic polymerizable compounds (a). The content of the photo-cationic polymerization initiator (B) in the 1 st active energy ray-curable composition is preferably 1.5 parts by mass or more and 8 parts by mass or less, and more preferably 2 parts by mass or more and 6 parts by mass or less, with respect to 100 parts by mass of the total amount of the cationically polymerizable compounds (a).

The photo cation polymerization initiator (B) is a substance which 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 a polymerization reaction of the cation polymerizable compound (a). The photo cationic polymerization initiator (B) functions as a catalyst by light, and therefore, even when it is mixed with the cationic polymerizable compound (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.

The photo cation polymerization initiator (B) is preferably at least one ionic compound selected from aromatic sulfonium salts and aromatic iodonium salts.

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.

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 1 st active energy ray-curable composition contains a photosensitizer (C) which exhibits a maximum absorption of light having a wavelength of more than 400nm (hereinafter, also simply referred to as photosensitizer (C)), and thus can improve the curability of the adhesive compared to the case where the photosensitizer (C) is not contained. In addition, even when the ultraviolet transmittance of the retardation layer and the adhesive layer between the retardation layers is low in the adhesion of the linear polarizing plate and the retardation layer laminate described later, the active energy ray-curable adhesive composition can be cured by irradiating ultraviolet light from the side of the retardation layer. In addition, in general, a linear polarizing plate disposed on the viewing side often contains an ultraviolet absorber, and conventionally, when ultraviolet light is irradiated from the side of the linear polarizing plate, it has been impossible to sufficiently cure an active energy ray-curable adhesive composition. However, by using a specific amount of the photosensitizer (C) as in the present invention, the active energy ray-curable adhesive composition can be cured by irradiating the photosensitizer (C) with an active energy ray from the side of the linear polarizer.

(wherein R is 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 a maximum absorption in a wavelength region of about 300nm or shorter, and generates a cation species or Lewis acid by sensing light of a wavelength in the vicinity thereof to initiate cation polymerization of the cationically polymerizable curable component, but the anthracene compound represented by the general formula (I) exhibits a maximum absorption in a wavelength region of more than 400mm, and can also sense light of a wavelength of more than 400 mm.

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.

The content of the photosensitizer (C) in the 1 st active energy ray-curable composition is preferably 0.1 part by mass or more and 5.0 parts by mass or less, and more preferably 0.5 part by mass or more and 3.0 parts by mass or less, with respect to 100 parts by mass of the total amount of the cationically polymerizable compounds (a).

(photosensitive auxiliary (D))

The 1 st active energy ray-curable 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 adding the naphthalene-based photosensitizing assistant to the 1 st active energy ray-curable composition, the curing rate of the adhesive can be increased as compared with the case where the naphthalene-based photosensitizing assistant is not added. Such an effect can be exhibited by setting the content of the naphthalene-based photosensitizing assistant to 0.1 part by mass or more with respect to 100 parts by mass of the total amount of the cationically polymerizable compound (a). On the other hand, when the content of the naphthalene-based photosensitizing assistant is increased, problems such as precipitation and the like occur during storage at low temperatures, it is preferable that the content thereof is 5 parts by mass or less with respect to 100 parts by mass of the total amount of the cationically polymerizable compound (a). The content of the naphthalene-based photosensitizing assistant is preferably 3 parts by mass or less based on 100 parts by mass of the total amount of the cationically polymerizable compound (a).

(additive component (E))

The 1 st active energy ray-curable 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 cationically polymerizable compounds (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 in the preparation of the 1 st active energy ray-curable composition, or may be added as it is after being diluted in a solvent. The numerical ranges of the above contents are all numerical ranges on a solid content basis.

(viscosity)

The viscosity of the 1 st active energy ray-curable composition may be any viscosity that can be applied by various methods, and is, for example, 200mPa · s or less, preferably 10mPa · s or more and 180mPa · s or less at a temperature of 25 ℃. If the viscosity is too low, a layer having a desired thickness tends to be less likely to be formed. On the other hand, if the viscosity is too high, the coating film tends to be less likely to flow and to be less likely to form a uniform coating film without unevenness. The viscosity here is a value measured at 10rpm after adjusting the temperature of the adhesive to 25 ℃ using an E-type viscometer.

(curing method)

The 1 st active energy ray-curable composition can be used in the form of an electron beam-curable composition or an ultraviolet-curable composition. In the present specification, the active energy ray is defined as an energy ray capable of decomposing a compound that generates an active species to generate an active species. Examples of such active energy rays include visible light, ultraviolet rays, infrared rays, X-rays, α -rays, β -rays, γ -rays, and electron beams.

The electron beam curing type may be any suitable conditions as long as the irradiation conditions of the electron beam are conditions under which the 1 st active energy ray-curable composition can be cured. 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 composition is not particularly limited, and the irradiation intensity of the 1 st active energy ray-curable 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 photo cation polymerization initiator (B), the photosensitizer (C), and the photo-sensitizer (D), 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 quantity of light to 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 required integrated light amount in which wavelength region (UVA (320nm to 390 nm) or UVB (280nm to 320 nm) or the like) is required differs depending on the types of the 1 st retardation layer 13 and the 2 nd retardation layer 30, the combination of the types of the adhesives, and the like.

The light source used for the polymerization curing of the 1 st active energy ray-curable 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 lamp, 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.

From the viewpoint of durability and adhesion, the 1 st active energy ray-curable composition preferably satisfies the following formula (1).

(J _A /J _B )×100≥60(％) (1)

[ wherein, J _A Represents: an amount of heat (unit: mJ/g) measured by a differential scanning calorimeter when ultraviolet rays having a peak at a wavelength of 365nm are irradiated to a1 st active energy ray-curable composition through a substrate having 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,

Heat quantity J _A And J _B The measurement can be carried out according to the method described in the section of examples below.

By using the 1 st active energy ray-curable composition satisfying the formula (1), good water resistance and adhesion tend to be easily obtained. The active energy ray-curable composition can be cured by irradiating the retardation layer having low ultraviolet transmittance, which has been difficult in the prior art, or the polarizing film 11 side with an active energy ray.

The left side of formula (1) is 70% or more, more preferably 80% or more. The left side of formula (1) is usually 100% or less, for example, less than 100% or 90% or less.

The storage modulus of the 1 st cured product layer 12 at 80 ℃ is, for example, 300MPa or more, and from the viewpoint of being less likely to crack during processing, it is preferably 500MPa or more, more preferably 900MPa or more, and still more preferably 1000MPa or more. The storage modulus at 80 ℃ can be determined according to the determination method described in the column of examples described later.

(retardation layer 1)

The 1 st retardation layer 13 is not particularly limited as long as it is a retardation layer including 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 dispersion property or a retardation layer having a reverse wavelength dispersion property. The 1 st retardation layer 13 may be formed of only a retardation-developing layer or may include both a 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.

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. The 1 st retardation layer 13 preferably contains a liquid crystal layer exhibiting retardation. When the 1 st retardation layer 13 includes a liquid crystal layer, the surface of the 1 st retardation layer 13 opposite to the 1 st cured product layer 12 side is preferably a liquid crystal layer exhibiting retardation. In general, the retardation-developing layer is more easily made thinner in the case of a liquid crystal layer than in the case of a stretched film.

The 1 st retardation layer 13 may have a light transmittance at a wavelength of 380nm of 0% or more and 50% or less (preferably 0% or more and 10% or less), and a light transmittance at a wavelength of 400nm of 30% or more. The light transmittance can be measured according to the measurement method described in the section of examples described later. The 1 st retardation layer 13 may have a light transmittance at a wavelength of 380nm of 0% or more and 5% or less, and a light transmittance at a wavelength of 400nm of 10% or more.

When the 1 st retardation layer 13 is formed only of the retardation-developing layer, the thickness is 0.5 μm or more and l0 μm or less, preferably 0.5 μm or more and 5 μm or less.

When the 1 st retardation layer 13 includes a layer (substrate layer, alignment film layer, protective layer, etc.) other than the retardation-developing layer, the overall thickness is 0.5 μm or more and 10 μm or less, and more preferably 0.5 μm or more and 5 μm or less.

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 that 220 nm. ltoreq. Re (550). ltoreq.290 nm be satisfied.

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 (b).

Re(450)≤Re(550)≤Re(650) (b)

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

The optical characteristics of the 1 st retardation layer 13 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.

(1) Phase difference 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. As shown in fig. 2, the retardation layer 30 is formed by sequentially laminating a base material layer 31, an alignment layer 32, and a retardation developing layer 33 as a liquid crystal layer. The retardation layer is not limited to the 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 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 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, but the base material layer 31 is preferably not included in order to set the entire thickness of the 1 st retardation layer 13 to 10 μm or less.

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, and curing the master after forming 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 the method for curing the composition containing the polymerizable liquid crystal compound include known methods such as irradiation with active energy rays (e.g., ultraviolet rays).

(2) 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 set in the heating furnace is in the range of from the vicinity of the glass transition temperature of the substrate (. degree.C.) to [ glass transition temperature +100] (. degree.C.), preferably in the range of 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 (strain)); "KC 8UX 2M", "KC 8 UY", and "KC 4 UY" (Konica Minolta Opto), etc.

Polymethacrylates and polyacrylates (hereinafter, polymethacrylates and polyacrylates are sometimes collectively referred to as (meth) acrylic resins) are readily available from the market.

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 (strain) ], "ZEONOR" (registered trademark) [ japan ZEON (strain) ], "ZEONEX" (registered trademark) [ japan ZEON (strain) ], and "APEL" (registered trademark) [ mitsui chemical (strain) ]. 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 (ltd) ], "SCA 40" (registered trademark) [ water chemical industry (ltd) ], "ZEONOR Film" (registered trademark) [ OPTES (ltd) ], and "Arton Film" (registered trademark) [ JSR (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.

(other layer)

The laminate 100 may have other layers in addition to the polarizing film 11, the 1 st cured product layer 12, and the 1 st phase difference layer 13. The other layers are explained with reference to fig. 3. As shown in fig. 3, in the laminate 100, a2 nd cured product layer 14 and a2 nd retardation layer 15 may be sequentially laminated on the 1 st retardation layer 13 on the opposite side of the 1 st cured product layer 12. In the laminate 100, a thermoplastic resin film 16 may be laminated on the side opposite to the 1 st cured product layer 12 of the polarizing plate 11 with an adhesive layer 17 interposed therebetween. In the laminate 100, the 2 nd retardation layer 15 side may have the adhesive layer 18.

(second cured product layer)

The 2 nd cured product layer 14 is disposed between the 1 st retardation layer 13 and the 2 nd retardation layer 15, and bonds the 1 st retardation layer 13 and the 2 nd retardation layer 15. The 2 nd cured product layer 14 contains a cured product of the 2 nd active energy ray-curable composition.

The 2 nd active energy ray-curable 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 2 nd active energy ray-curable composition may not contain any of a photosensitizer and a photosensitizing auxiliary agent. Examples and preferred ranges of the cationically polymerizable adhesive composition include those described in the description of the 1 st active energy ray-curable composition.

The thickness of the 2 nd cured product layer 14 is, for example, 20 μm or less, preferably 10 μm or less, more preferably 6 μm or less, and further preferably 5 μm or less. The thickness of the 2 nd cured product layer 14 is, for example, 0.5 μm or more, preferably 1 μm or more.

(retardation layer 2)

The 2 nd retardation layer 15 is not particularly limited as long as it is a retardation layer including at least one retardation-developing layer that imparts a predetermined retardation to light. The exemplary and preferred ranges of the 2 nd retardation layer 15 can be applied to the exemplary and preferred ranges of the 1 st retardation layer 13. Hereinafter, a laminate obtained by bonding the 2 nd retardation layer 15 and the 1 st retardation layer 13 with the 2 nd cured product layer 14 interposed therebetween is also referred to as a retardation layer laminate.

The 2 nd retardation layer 15 preferably contains a liquid crystal layer exhibiting retardation. In the case where the 2 nd retardation layer includes a liquid crystal layer, the surface of the 2 nd retardation layer 15 on the 2 nd cured product layer 14 side is preferably a liquid crystal layer exhibiting a retardation. When the laminate includes the 1 st retardation layer and the 2 nd retardation layer, at least one of the 1 st retardation layer and the 2 nd retardation layer preferably includes a liquid crystal layer exhibiting retardation.

The 2 nd retardation layer 15 may have a light transmittance at a wavelength of 380nm of 0% or more and 90% or less and a light transmittance at a wavelength of 400nm of 30% or more. The 2 nd retardation layer 15 may have a light transmittance at a wavelength of 380nm of 0% or more and 80% or less and a light transmittance at a wavelength of 400nm of 50% or more.

When the laminate includes the 1 st retardation layer and the 2 nd retardation layer, at least one of the 1 st retardation layer and the 2 nd retardation layer 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.

The thickness of the 2 nd retardation layer 15 is preferably 0.5 μm or more and 50 μm or less, and more preferably 0.5 μm or more and 5 μm or less.

Examples of the combination of the 1 st retardation layer 13 and the 2 nd retardation layer 15 include the following combinations:

i)1/2 wavelength layer and 1/4 wavelength layer,

ii)1/2 combination of wavelength layer and optical compensation layer,

iii)1/4 wavelength layer in combination with an optical compensation layer.

In the case of i), it is preferable that the 1 st retardation layer 13 is an 1/2 wavelength layer and the 2 nd retardation layer 15 is a 1/4 wavelength layer.

In the case of ii), the 1 st retardation layer 13 is preferably an 1/2-wavelength layer and the 2 nd retardation layer 15 is preferably an optical compensation layer, and more preferably the 1 st retardation layer 13 is a 1/2-wavelength layer and the 2 nd retardation layer 15 is a positive C plate.

In the case of iii), the 1 st retardation layer 13 is preferably an 1/4 wavelength layer and the 2 nd retardation layer 15 is preferably an optical compensation layer, and more preferably the 1 st retardation layer 13 is a 1/4 wavelength layer and the 2 nd retardation layer 15 is a positive C plate.

(thermoplastic resin film)

The thermoplastic resin film 16 may be disposed on the viewing side of the laminate. The thermoplastic resin film 16 may have a function of a protective film for protecting the polarizing film 11. A laminate obtained by laminating the polarizing film 11 and the thermoplastic resin film 16 with the adhesive layer 17 interposed therebetween is also referred to as a linear polarizing plate. Although not shown, the thermoplastic resin films may be disposed on both sides of the polarizing plate. 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 from the viewpoint of reduction in thickness.

The material of the thermoplastic resin film 16 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 16 is usually 300 μm or less, preferably 200 μm or less, more preferably 50 μm or less, and usually 5 μm or more, preferably 10 μm or more. The thermoplastic resin film 16 may or may not have a phase difference.

The thermoplastic resin film 16 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 needed.

(adhesive layer)

An adhesive layer 17 may be provided to adhere the thermoplastic resin film 16 to the polarizing film 11. The adhesive layer 17 preferably contains a cured product of an aqueous adhesive composition. The water-based adhesive composition may be obtained by using a polyvinyl alcohol resin or a urethane resin as a main component and adding a crosslinking agent such as an isocyanate compound or an epoxy compound or a curable compound to improve 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 an ultraviolet absorber, a filler, a flow regulator, an antifoaming agent, a leveling agent, a coloring matter, 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 aqueous adhesive composition is applied to one surface of a polarizing plate and dried to form a transparent adhesive.

The aqueous adhesive composition may be applied to one or both surfaces of the polarizing plate or the thermoplastic resin film and bonded thereto, and then heated to evaporate water vapor and perform a thermal crosslinking reaction to sufficiently bond the polarizing plate or the thermoplastic resin film and the thermoplastic resin film.

The thickness of the adhesive layer 17 is, for example, 20 μm or less, preferably 10 μm or less, and more preferably 5 μm or less. The thickness of the adhesive layer 17 may be 0.1 μm or more, for example.

(adhesive layer)

The laminate 100 may have an adhesive layer 18 on the 2 nd retardation layer 15 side. The pressure-sensitive adhesive layer 18 may be formed of a pressure-sensitive adhesive composition containing a resin such as a (meth) acrylic resin, a rubber resin, a urethane resin, an ester resin, a silicone resin, or a 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 an active energy ray-curable type or a heat-curable type. 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.

(method of producing laminate)

An example of the method for producing a laminate of the present invention will be described with reference to fig. 4. As shown in fig. 4(a), a linear polarizing plate 10 in which a polarizing film 11 and a thermoplastic resin film 16 are laminated with an adhesive layer 17 interposed therebetween is produced. As shown in fig. 4(B), a1 st retardation layer 13 including a1 st retardation-developing layer 21, a1 st alignment layer 22, and a1 st base material layer 23, and a2 nd retardation layer 15 including a2 nd retardation-developing layer 26, a2 nd alignment layer 25, and a2 nd base material layer 24 are prepared, and as shown in fig. 4(C), the 1 st retardation layer 13 and the 2 nd retardation layer 15 are laminated via the 2 nd cured layer 14, thereby producing a retardation layer laminate 50 in which the 1 st base material layer 23, the 1 st alignment layer 22, the 1 st retardation-developing layer 21, the 2 nd cured layer 14, the 2 nd retardation-developing layer 26, the 2 nd alignment layer 25, and the 2 nd base material layer 24 are laminated in this order. As shown in fig. 4(D), a laminate 70 was obtained by laminating the polarizing film 11 side of the linear polarizing plate 10 and the 1 st retardation layer 13 side of the retardation layer laminate 50 with the 1 st cured layer 12 interposed therebetween.

Examples of the method for bonding the polarizing film 11 and the thermoplastic resin film 16 include the following methods: the aqueous adhesive composition is applied to either or both of the contact surfaces of the polarizing film 11 and the thermoplastic resin film 16, and the contact surface of the other is laminated on the other, and the aqueous adhesive composition constituting the adhesive layer 17 is cured.

Examples of the method for bonding the 1 st retardation layer 13 and the 2 nd retardation layer 15 include the following methods: an active energy ray-curable composition is applied to either one or both of the bonding surface of the 1 st retardation layer 13 and the bonding surface of the 2 nd retardation layer 15, 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 14 is cured. The active energy ray for curing the 2 nd cured layer 14 may be irradiated from either side of the 1 st phase difference layer 13 and the 2 nd phase difference layer 15, or from both sides.

Examples of the method for bonding the linear polarizing plate 10 and the retardation layer laminate 50 include the following methods: an active energy ray-curable composition is applied to either one or both of the bonding surface of the linear polarizing plate 10 and the bonding surface of the retardation layer laminate 50, and the bonding surface of the other is laminated to one, and the active energy ray-curable adhesive constituting the 1 st cured layer 12 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 50. The active energy ray for curing the 1 st cured layer 12 may be irradiated from either side of the linear polarizing plate 10 and the phase difference layer laminated body 50, or from both sides.

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. For application of the aqueous adhesive composition and the active energy ray-curable 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 as shown in fig. 4(D), or a laminate obtained by peeling at least one of the 1 st substrate layer 23 and the 2 nd substrate layer 24. Further, a laminate obtained by peeling the 1 st base material layer 23 and the 1 st alignment layer 22 from the laminate shown in fig. 4(D) may be used, or a laminate obtained by peeling the 2 nd base material layer 24 and the 2 nd alignment layer 25 from the laminate shown in fig. 4(D) may be used.

(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, 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 laminate may have a function as a circularly polarizing plate or an antireflection film. The 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.

(measurement of viscosity)

The temperature of the active energy ray-curable composition was adjusted to 25 ℃ by using an E-type viscometer ("TVE-25" manufactured by Toyobo industries, Ltd.), and then measured at 10 rpm.

(calorimetric determination)

The active energy ray-curable adhesive composition was set in a differential scanning calorimeter, and the active energy ray-curable adhesive composition was irradiated with ultraviolet light having a peak at a wavelength of 365nm to measure the heat quantity J _B (unit: mJ/g). The heat quantity J is measured by irradiating the active energy ray-curable adhesive composition with ultraviolet rays having a peak at a wavelength of 365nm through a base material having 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 _A (unit: mJ/g).

(measurement of light transmittance)

The lambda/4 phase difference layer and the positive C plate were cut into a size of 30mm × 30mm, and the transmittance was measured at a wavelength of 200 to 510 nm. An ultraviolet-visible spectrophotometer "UV-2450" manufactured by Shimadzu corporation was used for the measurement.

(measurement of storage modulus at 80 ℃ C.)

The thus-prepared active energy ray-curable composition was coated on one side of a polyethylene terephthalate film (trade name: TOYOBOESTERFELM E7002, manufactured by TOYOBOESTERFELM Co., Ltd.) by using a coater (bar coater, manufactured by first chemical and chemical Co., Ltd.) so that the film thickness after curing was about 10 μm. Next, the Fusion UV Systems was usedSeaman "D Bulb" to accumulate light quantity of 1,000mJ/cm ² The adhesive is cured by irradiating ultraviolet rays. The resultant was cut into a size of 5mm × 30mm, and the polyethylene terephthalate film was peeled off to obtain a cured film of the adhesive. The cured film thus obtained was held at a distance of 2cm from each other by a dynamic viscoelasticity measuring apparatus "DVA-220" manufactured by the ltd meter system so that the long side thereof was oriented in the stretching direction, the frequency of stretching and shrinking was set to 1Hz, and the temperature increase rate was set to 3 ℃/min, to obtain the storage modulus at a temperature of 80 ℃.

(measurement of adhesion)

An acrylic adhesive (having a thickness of 25 μm) was applied to the C-plate side of the laminates prepared in examples and comparative examples, and the laminates were cut into a size of 200mm in length by 25mm in width, and then the 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/4 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 Table 1.

O: 180 DEG peeling force of 0.5N or more

X: 180 DEG peeling force less than 0.5N

(evaluation of durability)

The laminated bodies prepared in examples and comparative examples were cut into a size of 30mm × 30mm, subjected to a moist heat test in which they were left to stand in a moist heat environment at a temperature of 80 ℃ and a relative humidity of 90% for 24 hours, and the degrees of polarization and the phase difference values before and after the test were measured to determine the absolute values of the differences, and evaluated based on the following criteria.

Standard of degree of polarization:

very good: 1.0 or less

O: more than 1.0 and not more than 3.0

X: over 3.0

Reference of in-plane retardation value:

very good: 0.5 or less

O: more than 0.5 and not more than 1.0

X: over 1.0

In the measurement of the degree of polarization, the transmission spectrum in the transmission axis direction and the absorption axis direction of the polarizing plate in the wavelength range of 380nm to 780nm was determined using a device equipped with an optional "polarizer-attached film holder" in an ultraviolet-visible spectrophotometer "UV-2450" manufactured by shimadzu corporation, ltd, and the degree of polarization was calculated from the software "UV-Probe" attached to the spectrophotometer.

The in-plane retardation value R was measured using a retardation measuring device "KOBRA-WR" manufactured by Oji instruments, Inc., to obtain an in-plane retardation value R having a wavelength of 550nm _e 。

The in-plane retardation value Re is defined by the following equation.

R _e ＝(n _x -n _y )×d

The refractive index in the in-plane slow axis direction (the direction in which the refractive index is the largest in the plane) is represented by n _x The refractive index in the in-plane fast axis direction (the direction orthogonal to the in-plane slow axis direction) is n _y The thickness of the laminate is denoted by d. )

(preparation of active energy ray-curable composition 1.)

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 the 1 st active energy ray-curable composition (adhesives 1 to 13). The cationic polymerization initiator (B-1) was blended as a 50% propylene carbonate solution, and the amount of the solid content thereof is shown in table 1. The results of the viscosity measurement and the results of the heat measurement are shown in Table 2.

[ Table 1]

(cationically polymerizable Compound (A))

A-1: 3-Ethyl-3- { [ (3-ethyloxetan-3-yl) methoxy ] methyl } oxetane (trade name: OXT-221, manufactured by TOYA SYNTHESIS CO., LTD., viscosity 0.012 Pa.s (temperature 25 ℃ C.), refractive index 1.45 (wavelength 589nm))

A-2: 3, 4-Epoxycyclohexanecarboxylic acid 3 ', 4' -epoxycyclohexylmethyl ester (trade name: CEL2021P, manufactured by DAICEL, viscosity 0.25 pas (temperature 25 ℃ C.), refractive index 1.50 (wavelength 589nm))

A-3: 1, 2-epoxy-4- (2-epoxyethyl) cyclohexane adduct of 2, 2-bis (hydroxymethyl) -1-butanol (trade name: EHPE3150, manufactured by DAICEL, Ltd., viscosity exceeding 30 pas (temperature 25 ℃ C.), refractive index 1.54 (wavelength 589nm))

A-4: neopentyl glycol diglycidyl ether (trade name: EX-211L, manufactured by Nagase ChemteX, viscosity 0.02 pas (temperature 25 ℃ C.), refractive index 1.45 (wavelength 589nm))

A-5: 2-ethylhexyl glycidyl ether (trade name: EX-121, manufactured by Nagase ChemteX, Ltd., viscosity 0.004 Pa.s (temperature 25 ℃ C.), refractive index 1.43 (wavelength 589nm))

A-6: bisphenol A type epoxy resin (trade name: jER828, manufactured by Mitsubishi chemical Co., Ltd., viscosity 13 Pa. s (temperature 25 ℃ C.), refractive index 1.57 (wavelength 589nm))

A-7: xylylene dioxyoxetane (trade name: OXT-121, manufactured by Toyo Seiya, viscosity 0.15 Pa.s (temperature 25 ℃ C.), refractive index 1.51 (wavelength 589nm))

(photo cation polymerization initiator (B))

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

(photosensitizer (C))

C-1: 9, 10-dibutoxyanthracene

(photosensitive auxiliary (D))

D-1: 1, 4-diethoxynaphthalenes

[ Table 2]

(2 nd active energy ray-curable composition)

A2 nd actinic energy ray-curable composition was prepared by mixing 70 parts by mass of 3, 4-epoxycyclohexanecarboxylic acid 3 ', 4' -epoxycyclohexylmethyl ester (trade name: CEL2021P, manufactured by DAICEL), 20 parts by mass of neopentyl glycol diglycidyl ether (trade name: EX-211L, manufactured by Nagase ChemteX), 10 parts by mass of 2-ethylhexyl glycidyl ether (trade name: EX-121, manufactured by Nagase ChemteX), 2.25 parts by mass as a solid content of a cationic polymerization initiator (trade name: CPI-100P, manufactured by San-Apro), and 2 parts by mass of 1, 4-diethoxynaphthalene, and defoaming the mixture.

(acrylic pressure-sensitive adhesive sheet A)

(1) Preparation of the Material

An acrylic base polymer (H-1), an isocyanate crosslinking agent (H-2) and a silane coupling agent (H-3) were prepared as shown below.

(H-1) copolymer of butyl acrylate, methyl acrylate, acrylic acid and hydroxyethyl acrylate

(H-2) Ethyl acetate solution (solid content concentration 75%) of trimethylolpropane adduct of tolylene diisocyanate ("Coronate L" (trade name), manufactured by Tosoh corporation)

(H-3) 3-glycidoxypropyltrimethoxysilane, liquid ("KBM-403" (trade name), manufactured by shin-Etsu chemical Co., Ltd.)

(2) Preparation of adhesive 1

Adhesive 1 was prepared by mixing 100 parts by mass of acrylic base polymer (H-1), 0.2 part by mass of isocyanate-based crosslinking agent (H-2), and 0.2 part by mass of silane coupling agent (H-3), stirring thoroughly, and diluting with ethyl acetate.

(3) Production of acrylic pressure-sensitive adhesive sheet A

The adhesive 1 prepared above was coated on release paper and heat-treated at 90 ℃ for 1 minute to obtain an acrylic adhesive sheet a. The obtained adhesive layer was peeled from the release paper and measured for thickness, resulting in 5 μm. The thickness of the adhesive layer was measured by a contact thickness meter [ trade name "DIGIMICRO MH-15M" manufactured by Nikon corporation ].

(acrylic pressure-sensitive adhesive sheet B)

The adhesive 1 for producing the acrylic adhesive sheet a was coated on release paper so that the thickness of the adhesive layer became 25 μm, and heat-treated at 90 ℃ for 1 minute to obtain an acrylic adhesive sheet B.

(production of Linear polarizing plate)

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 4.5 times at a stretch ratio on a roll heated to 125 ℃ and, while being kept in a taut state, immersed in 28 ℃ water for 30 seconds, 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 5.5 parts by mass of boric acid and 15 parts by mass of potassium iodide per 100 parts by mass of water for 30 seconds. Thereafter, the film was washed with pure water at 10 ℃ and dried at 80 ℃ to obtain a polarizing film. The thickness of the obtained polarizing film was 7 μm.

Further, a cycloolefin film (COP film) with a hard coat layer having a thickness of 25 μm was bonded to one surface of the obtained polarizing film via an aqueous adhesive (thickness 0.1 μm) on the opposite side of the hard coat layer, and dried at 90 ℃. The aqueous adhesive was prepared by adding 3 parts of acetoacetyl-modified polyvinyl alcohol (Z-200, manufactured by Nippon corporation) and 1.5 parts of water-soluble polyamide epoxy Resin (Sumirez Resin 650, manufactured by Sumirez ChemteX, Inc., an aqueous solution having a solid content of 30%) to 100 parts of water.

(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 on which an alignment film was laminated, and cured while maintaining refractive index anisotropy, thereby obtaining a phase difference-developing layer having a thickness of 1 μm on the transparent resin substrate. The obtained λ/4 retardation layer had a light transmittance at a wavelength of 380nm of 0% and a light transmittance at a wavelength of 400nm of 30% or more.

(production of Positive C plate)

A composition for forming a vertically aligned film was applied to one surface of a substrate film to a film thickness of 3 μm, and irradiated at 200mJ/cm ² The above ultraviolet ray was used to prepare a vertically aligned film. The positive C plate-forming composition is applied to the vertical alignment layer, dried, and then irradiated with Ultraviolet (UV) rays to polymerize the polymerizable liquid crystal compound, thereby obtaining a positive C plate. The positive C plate obtained had a light transmittance at a wavelength of 380nm of 80% and a light transmittance at a wavelength of 400nm of 90% or more.

(production of retardation layer laminate)

The liquid crystal layer side of the lambda/4 phase difference layer and the positive C plate was subjected to corona treatment. The liquid crystal layers were laminated together using the 2 nd active energy ray-curable composition by a laminator so that the thickness of the cured product layer became 2 μm, to obtain a laminate.

From the side of the front C-plate of the laminate obtained, an ultraviolet irradiation apparatus [ manufactured by Fusion UV Systems (Ltd.) was used to accumulate the light quantity at 400mJ/cm ² (UV-A) ultraviolet irradiation was performed to cure the 2 nd active energy ray-curable composition to form a2 nd cured product layer, and a retardation layer laminate having a laminate structure of "lambda/4 retardation layer" (1 st retardation layer)/adhesive layer (2 nd cured product layer)/"positive C plate" (2 nd retardation layer) was obtained.

< example 1>

The alignment film and the transparent resin substrate on the λ/4 retardation layer side of the obtained retardation layer laminate were peeled off, and the surface of the linear polarizing plate opposite to the thermoplastic resin film and the liquid crystal layer of the λ/4 retardation layer were bonded using adhesive 1. The thickness of the 1 st cured product layer made of the adhesive 1 was 2 μm, and the angle formed between the transmission axis of the polarizing plate and the slow axis of the λ/4 retardation layer was 45 °.

Next, the alignment film on the positive C-plate side and the transparent resin substrate were peeled off to obtain a laminate of example 1 having a laminated structure of COP film (thermoplastic resin film)/aqueous adhesive (adhesive layer)/polarizing plate/1 st cured product layer (cured product layer of adhesive 1)/"λ/4 retardation layer" (1 st retardation layer)/2 nd cured product layer (cured product layer of 2 nd active energy ray-curable composition)/"positive C-plate" (2 nd retardation layer). The evaluation results of storage modulus at 80 ℃, adhesion and durability are shown in table 3.

< examples 2 to 10 and comparative examples 1 to 3>

Laminates of examples 2 to 11 and comparative examples 1 to 3 were produced in the same manner as in example 1, except that the adhesives 2 to 10 and the adhesives 11 to 13 were used instead of the adhesive 1. The results are shown in Table 3.

< comparative example 4>

An acrylic pressure-sensitive adhesive sheet a having a pressure-sensitive adhesive layer thickness of 5 μm was bonded to the surface of the linear polarizing plate opposite to the thermoplastic resin film to form an acrylic pressure-sensitive adhesive layer a. The alignment film on the lambda/4 retardation layer side of the retardation layer laminate was peeled from the transparent resin substrate. The liquid crystal layer of the λ/4 retardation layer of the retardation layer laminate was bonded to the acrylic pressure-sensitive adhesive layer a of the linear polarizing plate. The transmission axis of the polarizer makes an angle of 45 with the slow axis of the λ/4 phase difference layer.

Next, the alignment film on the front C plate side and the transparent resin substrate were peeled off to obtain a laminate of comparative example 1 having a laminate structure of COP film (thermoplastic resin film)/aqueous adhesive (adhesive layer)/polarizing plate/acrylic adhesive layer a/"λ/4 retardation layer" (1 st retardation layer)/2 nd cured layer (cured layer of 2 nd active energy ray-curable composition)/"C plate" (2 nd retardation layer). The obtained laminate was evaluated for water resistance. The results are shown in Table 3.

< comparative example 5>

A laminate of comparative example 5 was obtained in the same manner as in comparative example 4, except that an acrylic pressure-sensitive adhesive layer B having a thickness of 25 μm was formed using an acrylic pressure-sensitive adhesive sheet B instead of using the acrylic pressure-sensitive adhesive sheet a in comparative example 4 to form an acrylic pressure-sensitive adhesive layer a having a thickness of 5 μm. The results are shown in Table 3.

[ Table 3]

Description of the symbols

10 linear polarization plates; 11 a polarizing film; 12 a1 st cured layer; 13 the 1 st phase difference layer; 14 a2 nd cured layer; 15 a2 nd retardation layer; 16 a thermoplastic resin film; 17 an adhesive layer; 18 an adhesive layer; 20, 1 st phase difference layer; 21 a base material layer; 22 an orientation layer; 23 a phase difference developing layer; 24 a substrate layer; 25 an orientation layer; 26 a phase difference developing layer; 30 phase difference layers; 31 a base material layer; 32 an orientation layer; 33 a phase difference developing layer; a 50 phase difference layer laminate; 70 a laminate; 100 of stacked bodies.

Claims

1. A laminate comprising a polarizing film, a1 st cured product layer and a1 st retardation layer laminated in this order, wherein the 1 st retardation layer has a thickness of 10 [ mu ] m or less, and the 1 st cured product layer comprises a cured product of a1 st active energy ray-curable composition,

the 1 st active energy ray-curable composition contains (A) a cationically polymerizable compound and (B) a photocationic polymerization initiator, and contains the (B) photocationic polymerization initiator in an amount of 1 to 10 parts by mass based on 100 parts by mass of the cationically polymerizable compound (A),

the cationically polymerizable compound (A) contains an oxetane compound in an amount of 45 mass% or more based on the total mass of the cationically polymerizable compound (A).

2. The laminate according to claim 1, wherein the 1 st active energy ray-curable composition contains 0.1 to 3.0 parts by mass of (C) a photosensitizer exhibiting a maximum absorption of light having a wavelength of more than 400nm, based on 100 parts by mass of the cationically polymerizable compound (A),

the photosensitizer (C) comprises an anthracene compound represented by the following general formula (I),

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.

3. The laminate according to claim 1 or 2, wherein the oxetane compound is at least one selected from the group consisting of 3-ethyl-3-hydroxymethyloxetane, xylylene-bisoxetane, 3-ethyl-3- (phenoxymethyl) oxetane, 3-ethyl-3- { [ (3-ethyloxetan-3-yl) methoxy ] methyl } oxetane, 3-ethyl-3- (2-ethylhexyloxymethyl) oxetane, 3-ethyl-3- (cyclohexyloxymethyl) oxetane.

4. The laminate according to any one of claims 1 to 3, wherein the cationically polymerizable compound (A) contains 10% by mass or more and 50% by mass or less of an alicyclic epoxy compound based on the total mass of the cationically polymerizable compound (A).

5. The laminate according to any one of claims 1 to 4, wherein the photo-cationic polymerization initiator (B) is at least one ionic compound selected from aromatic sulfonium salts and aromatic iodonium salts.

6. The laminate according to any one of claims 1 to 5, wherein the 1 st active energy ray-curable composition has a viscosity of 200 mPas or less at 25 ℃.

7. The laminate according to any one of claims 1 to 6, wherein the 1 st active energy ray-curable composition satisfies the following formula (1),

(J _A /J _B )×100≥60(％) (1)

J _A represents: transmitting ultraviolet rays having a peak at a wavelength of 365nm through a light ray having a transmittance at a wavelength of 380nm of 0% to 10%, and a transmittance at a wavelength of 400nmA heat quantity measured by a differential scanning calorimeter when a substrate having a light transmittance of 30% or more is irradiated to the 1 st active energy ray-curable composition, the heat quantity having a unit of mJ/g,

J _B represents: the heat quantity measured by a differential scanning calorimeter when ultraviolet rays having a peak at a wavelength of 365nm are irradiated to the 1 st active energy ray-curable composition without passing through a substrate is expressed in mJ/g.

8. The laminate according to any one of claims 1 to 7, wherein the 1 st cured product layer has a storage modulus at 80 ℃ of 300MPa or more.

9. The laminate according to any one of claims 1 to 8, wherein the thickness of the 1 st cured product layer is 0.5 μm or more and 10 μm or less.

10. The laminate according to any one of claims 1 to 9, wherein the 1 st retardation layer has a light transmittance at a wavelength of 380nm of 0% or more and 50% or less, and a light transmittance at a wavelength of 400nm of 30% or more.

11. The laminate according to any one of claims 1 to 10, wherein the 1 st retardation layer 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.

12. The laminate according to any one of claims 1 to 11, wherein a2 nd cured product layer and a2 nd cured product layer are laminated in this order on the opposite side of the 1 st cured product layer from the 1 st cured product layer,

the 2 nd cured product layer contains a cured product of a2 nd active energy ray-curable composition, and at least one of the 1 st retardation layer and the 2 nd retardation layer 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.

13. The laminate according to claim 12, wherein the 1 st retardation layer is an 1/2-wavelength retardation layer, and the 2 nd retardation layer is an 1/4-wavelength retardation layer.

14. The laminate according to claim 12, wherein the 1 st retardation layer is an 1/2 wavelength retardation layer or a 1/4 wavelength retardation layer, and the 2 nd retardation layer is a positive C plate.

15. The laminate according to any one of claims 12 to 14, wherein at least one of the 1 st phase difference layer and the 2 nd phase difference layer comprises a phase difference-developing liquid crystal layer.

16. The laminate according to any one of claims 12 to 15, wherein at least one of the 1 st retardation layer and the 2 nd retardation layer has a thickness of 0.5 μm or more and 50 μm or less.

17. A circularly polarizing plate comprising the laminate according to any one of claims 1 to 16.

18. An image display device comprising an image display panel, and the laminate according to any one of claims 1 to 17 disposed on a viewing side of the image display panel.

19. The image display device according to claim 18, wherein the laminate is disposed in an orientation in which the polarizing film is on a viewing side.

20. An organic electroluminescent display device comprising the image display device according to claim 18 or 19.