WO2021153019A1

WO2021153019A1 - Optical laminate and display device in which same is used

Info

Publication number: WO2021153019A1
Application number: PCT/JP2020/045824
Authority: WO
Inventors: 福田　謙一
Original assignee: 住友化学株式会社
Priority date: 2020-01-31
Filing date: 2020-12-09
Publication date: 2021-08-05
Also published as: CN115023634A; JP2021121841A; TW202138180A; KR20220126778A

Abstract

The purpose of the present invention is to provide an optical laminate with which it is possible to enhance visibility in a manner unrelated to the presence of polarized sunglasses, even after placement in a high-temperature environment. The present invention provides an optical laminate comprising a high-phase-contrast film, a polarizer, and an adhesive agent layer, the optical laminate being such that the adhesive agent layer is provided so as to be in contact with the surface of the polarizer, the in-plane phase contrast value of the high-phase-contrast film is 3000-30000 nm, and the angle formed by the slow axis of the high-phase-contrast film and the absorption axis of the polarizer is 40-50°.

Description

Optical laminate and display device using it

The present invention relates to an optical laminate and a display device using the same.

In recent years, with the rapid spread of liquid crystal display devices, the number of scenes where they are used in strong sunlight such as smartphone applications and in-vehicle applications is increasing. In such strong sunlight, it may be used with sunglasses having polarized characteristics (polarized sunglasses) worn, and when the liquid crystal display device is visually recognized through the polarized sunglasses, the liquid crystal display is displayed depending on the viewing direction. The device could become dark and the visibility could be significantly reduced.

In Patent Document 1, a white light emitting diode is used as a backlight of a liquid crystal display device, and a polymer film having a retardation of 3000 nm to 30,000 nm is provided on the viewer side of the polarizer of the absorption shaft of the polarizer and the polymer film. A method for improving visibility is described in which the angle formed by the slow axis is approximately 45 °. According to the visibility improving method of Patent Document 1, it is said that the visibility when observing the screen through polarized sunglasses can be improved. However, when such a polymer film having a high retardation value is used, the front luminance of the liquid crystal display device at the time of black display increases when it is left in a high temperature environment for a long time, and polarized sunglasses are not worn. When the screen was visually recognized, the visibility was sometimes lowered.

Japanese Unexamined Patent Publication No. 2011-215646

An object of the present invention is to solve the above problems, and to provide an optical laminate capable of improving visibility regardless of the presence or absence of polarized sunglasses even after being placed in a high temperature environment.

As a result of diligent studies, the present inventor has applied a polymer film having a retardation value of 3000 nm to 30,000 nm (hereinafter, also simply referred to as “high retardation film”) on the surface of the polarizing plate used for the visible side surface of the liquid crystal display device. When the liquid crystal display device bonded so that the angle between the absorption axis of the polarizer and the slow axis of the polymer film is approximately 45 ° is left in a high temperature environment for a long time, the liquid crystal display device displays black. It was considered that the reason why the front brightness of the film increased was as follows.

The high retardation film is stretched at a high temperature and at a high stretching ratio, and is cooled and manufactured with residual stress remaining. When a polarizing plate to which such a high retardation film is diagonally bonded is stored for a long time in a high temperature environment, the residual stress in the diagonal direction of the high retardation film is released. This stress in the oblique direction is also applied to the protective film of the polarizing plate, and in particular, for the protective film arranged between the polarizer and the liquid crystal display device, the phase difference having the optical axis diagonally with respect to the absorption axis of the polarizer is large. It was presumed that this was due to light leakage.

Based on this estimation, it was found that the above problems could be solved by not arranging a protective film between the polarizer and the liquid crystal display device, and the present invention was completed.

The present invention provides an optical laminate illustrated below and a display device using the same.
[1] A high retardation film, a polarizer, and an adhesive layer are provided in this order.
The pressure-sensitive adhesive layer is provided so as to be in contact with the surface of the polarizer.
The in-plane retardation value of the high retardation film is 3000 nm to 30,000 nm.
An optical laminate in which the angle formed by the slow axis of the high retardation film and the absorption axis of the polarizer is 40 ° to 50 °.
[2] A high retardation film, a polarizer, a resin layer containing a cured resin product, and an adhesive layer are provided in this order.
The resin layer is provided so as to be in contact with the polarizer and the pressure-sensitive adhesive layer.
The in-plane retardation value of the high retardation film is 3000 nm to 30,000 nm.
An optical laminate in which the angle formed by the slow axis of the high retardation film and the absorption axis of the polarizer is 40 ° to 50 °.
[3] The optical laminate according to [2], wherein the resin layer is an overcoat layer.
[4] The optical laminate according to any one of [1] to [3], further comprising a protective film provided between the high retardation film and the polarizer.
[5] The optical laminate according to any one of [1] to [4], wherein the polarizer has a thickness of 30 μm or less.
[6] The optical laminate according to any one of [1] to [5], wherein the high retardation film has a thickness of 200 μm or less.
[7] The image display element and the optical laminate according to any one of [1] to [6] are provided.
A display device in which the pressure-sensitive adhesive layer of the optical laminate is bonded to the surface of the image display element.

According to the present invention, it is possible to provide an optical laminate capable of improving visibility regardless of the presence or absence of polarized sunglasses even after being placed in a high temperature environment.

It is an example of the schematic cross-sectional view which shows the layer structure of the optical laminated body of 1st Embodiment. It is an example of the schematic cross-sectional view which shows the layer structure of the optical laminated body of 2nd Embodiment.

(Definition of terms and symbols)
Definitions of terms and symbols herein are as follows.
(1) Refractive index (nx, ny, nz)
"Nx" is the refractive index in the direction in which the in-plane refractive index is maximized (that is, the slow-phase axis direction), and "ny" is the in-plane refractive index in the direction orthogonal to the slow-phase axis. Is the refractive index in the thickness direction.
(2) In-plane retardation value The in-plane retardation value (Re [λ]) refers to the in-plane retardation value of the film at 23 ° C. and a wavelength of λ (nm). Re [λ] is obtained by Re [λ] = (nx−ny) × d, where d (nm) is the thickness of the film.
(3) Phase difference value in the thickness direction The in-plane phase difference value (Rth [λ]) refers to the phase difference value in the thickness direction of the film at 23 ° C. and a wavelength of λ (nm). Rth [λ] is obtained by Rth [λ] = ((nx + ny) / 2-nz) × d, where d (nm) is the thickness of the film.

<Optical laminate>
The optical laminate of the present invention includes a high retardation film, a polarizer, and a pressure-sensitive adhesive layer (hereinafter, also referred to as “first pressure-sensitive adhesive layer”) in this order. Each layer in the optical laminate can be laminated, for example, via an adhesive layer. Examples of the adhesive layer include an adhesive layer and an adhesive layer described later.

FIG. 1 is a diagram showing an example of the layer structure of the optical laminate of the first embodiment. In the optical laminate 100 shown in FIG. 1, a high retardation film 13, a polarizing plate 1 including a polarizing element 10, and a first pressure-sensitive adhesive layer 15 are laminated in this order. The polarizing plate 1 includes a polarizing element 10 and a protective film 12 laminated on the high retardation film 13 side of the polarizing element 10. The first pressure-sensitive adhesive layer 15 is provided so as to be in contact with the surface of the polarizer 10.

FIG. 2 is a diagram showing an example of the layer structure of the optical laminate of the second embodiment. In the optical laminate 200 shown in FIG. 2, a high retardation film 13, a polarizing plate 1 including a polarizing element 10 and a resin layer 11, and a first pressure-sensitive adhesive layer 15 are laminated in this order. The polarizing plate 1 includes a polarizing element 10, a protective film 12 laminated on the high retardation film 13 side of the polarizing element 10, and a resin layer provided so as to be in contact with the surface of the polarizing element 10 on the first adhesive layer 15 side. 11 and. The resin layer 11 contains a cured resin product. The first pressure-sensitive adhesive layer 15 is provided so as to be in contact with the surface of the resin layer 11.

The high retardation film 13 and the polarizing plate 1 are laminated via an adhesive layer (hereinafter, also referred to as “second adhesive layer”) 14. The first pressure-sensitive adhesive layer 15 can be a pressure-sensitive adhesive layer for bonding to a display element or the like.

<Polarizer>
The polarizing plate 1 includes at least a polarizing element 10, and may have a protective film 12, a resin layer 11, and the like as other components. 1 and 2 show a configuration in which one protective film 12 is provided between the polarizer 10 and the high retardation film 13, but two protective films are provided between the polarizer 10 and the high retardation film 13. The configuration may be provided as described above. The protective film may have a surface treatment layer such as a hard coat layer, an antireflection layer, and an antistatic layer, which will be described later. Further, the protective film may be a film that functions as a retardation film. The polarizer and the protective film can be laminated, for example, via an adhesive layer or an adhesive layer. The protective film and the protective film can be laminated, for example, via an adhesive layer or an adhesive layer. The members included in the polarizing plate will be described below.

(1) Polarized light The polarizer 10 included in the polarizing plate 1 absorbs linearly polarized light having a vibrating surface parallel to its absorption axis, and linearly polarized light having a vibrating surface orthogonal to the absorption axis (parallel to the transmission axis). It can be an absorption type polarizer having a transmissive property. As the polarizer 10, a polarizer in which a dichroic dye is adsorbed and oriented on a uniaxially stretched polyvinyl alcohol-based resin film can be preferably used. The polarizer 10 is, for example, a step of uniaxially stretching a polyvinyl alcohol-based resin film; a step of adsorbing a dichroic dye by dyeing the polyvinyl alcohol-based resin film with a dichroic dye; the dichroic dye is adsorbed. It can be produced by a method including a step of treating a polyvinyl alcohol-based resin film with a cross-linking solution such as an aqueous boric acid solution; and a step of washing with water after the treatment with the cross-linking solution.

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

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

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

A film formed of such a polyvinyl alcohol-based resin is used as a raw film for a polarizer. The method for forming a film of the polyvinyl alcohol-based resin is not particularly limited, and a known method is adopted. The thickness of the polyvinyl alcohol-based raw film is not particularly limited, but for example, in order to reduce the thickness of the polarizer to 25 μm or less, it is preferable to use one having a thickness of 40 to 75 μm. More preferably, it is 45 μm or less.

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

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

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

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

The thickness of the polarizer is usually 50 μm or less, preferably 5 to 30 μm, more preferably 5 to 25 μm or less, and further preferably 5 to 20 μm or less. By setting the thickness of the polarizer within these ranges, it is possible to maintain handleability while preventing breakage or cracking during manufacturing of the polarizer, and it is possible to achieve both high optical characteristics. Further, by setting the thickness of the polarizer to 20 μm or less, it is possible to further suppress a decrease in visibility when placed in a high temperature environment.

As the polarizer, for example, as described in JP-A-2016-170368, a cured film in which a liquid crystal compound is polymerized may be used in which a dichroic dye is oriented. As the dichroic dye, a dye having absorption in the wavelength range of 380 to 800 nm can be used, and it is preferable to use an organic dye. Examples of the dichroic dye include an azo compound. The liquid crystal compound is a liquid crystal compound that can be polymerized while being oriented, and can have a polymerizable group in the molecule. Further, as described in WO2011 / 024891, a polarizer may be formed from a dichroic dye having a liquid crystallinity.

(2) Protective film The polarizing plate 1 may have a protective film 12 laminated on the surface of the polarizer 10 on the high retardation film 13 side.

The protective film 12 is not particularly limited, and is, for example, a polyolefin resin such as a chain polyolefin resin (polypropylene resin or the like) or a cyclic polyolefin resin (norbornen resin or the like); such as triacetyl cellulose or diacetyl cellulose. Cellular resin; polyester resin such as polyethylene terephthalate and polybutylene terephthalate; polycarbonate resin; (meth) acrylic resin such as methyl methacrylate resin; polystyrene resin; polyvinyl chloride resin; acrylonitrile butadiene -Styrene resin; acrylonitrile-styrene resin; polyvinyl acetate resin; polyvinylidene chloride resin; polyamide resin; polyacetal resin; modified polyphenylene ether resin; polysulfone resin; polyether sulfone resin; polyallylate resin A film made of a resin; a polyamide-based resin; a polyimide-based resin; a maleimide-based resin or the like can be used. Of these, a chain polyolefin resin film and a cellulosic resin film are preferably used.

As the chain polyolefin resin, polyethylene resin (polyethylene resin which is a homopolymer of ethylene or a copolymer mainly composed of ethylene), polypropylene resin (polypropylene resin which is a homopolymer of propylene or propylene as a main component) are used. In addition to homopolymers of chain olefins such as (copolymers), copolymers composed of two or more kinds of chain olefins can be mentioned.

Cellulose ester resin is an ester of cellulose and fatty acid. Specific examples of the cellulose ester resin include cellulose triacetate, cellulose diacetate, cellulose tripropionate, and cellulose dipropionate. In addition, these copolymers and those in which a part of the hydroxyl group is modified with another substituent can also be mentioned. Among these, cellulose triacetate (triacetyl cellulose) is particularly preferable.

The thickness of the protective film 12 is usually 1 to 100 μm, but is preferably 5 to 60 μm, more preferably 10 to 55 μm, and even more preferably 15 to 50 μm from the viewpoint of strength, handleability, and the like. ..

As described above, the protective film 12 has a hard coat layer, an antiglare layer, a light diffusing layer, an antireflection layer, a low refractive index layer, an antistatic layer, and an antistatic layer on its outer surface (the surface opposite to the polarizer). It may be provided with a surface treatment layer (coating layer) such as a foul layer. The thickness of the protective film 12 includes the thickness of the surface treatment layer. When the protective film 12 and another protective film are provided between the polarizer 10 and the high retardation film 13, the above description of the protective film 12 applies to the other protective film. The thickness, material, etc. of the other protective film may be the same as or different from that of the protective film 12.

(3) Resin layer The resin layer 11 contains a cured resin product. The resin layer 11 may be composed of only a cured resin product. The resin layer 11 is a layer formed by curing the curable resin composition. The resin layer 11 has a three-dimensional crosslinked structure. The resin layer 11 is distinguished from a resin film such as a protective film based on the crosslinked structure or the difference in the composition or molecular structure of the monomer.

The resin layer 11 may be an overcoat layer. The overcoat layer can be rephrased as a layer formed by curing an uncured curable resin composition that covers the surface of the polarizer 10. For example, the resin layer 11 is formed by directly applying an uncured curable resin to the surface of the polarizer 10 to form a layer containing the uncured curable resin (uncured layer) and curing the uncured layer. You may get it. Alternatively, by forming an uncured layer on the surface of the base film, transferring the uncured layer from the base film to the surface of the polarizer 10, and curing the uncured layer transferred to the surface of the polarizer 10. , The resin layer 11 may be obtained. When the uncured layer is brought into close contact with the surface of the polarizer 10, the relatively soft uncured layer easily bites into the fine irregularities on the surface of the polarizer 10 without gaps, and the resin layer 11 obtained by curing the uncured layer is also polarized. It is easy to bite into the fine irregularities on the surface of the child 10 without any gaps. As a result, an anchor effect may occur, and the anchor effect may easily suppress cracks in the polarizer 10.

The cured resin product constituting the resin layer 11 may be formed from a photocurable resin composition that is cured by irradiation with active energy rays. The cured resin product constituting the resin layer 11 may be formed from a thermosetting resin composition that is cured by heating. The cured resin product constituting the resin layer 11 may contain a cured product of an epoxy compound. The cured resin product constituting the resin layer 11 may contain a cured product of an oxetane-based compound. The cured resin product constituting the resin layer 11 may contain a cured product of a (meth) acrylic compound. Hereinafter, specific examples of the curable resin composition suitable for forming the resin layer 11 (cured resin product) will be described in detail.

<Curable resin composition for resin layer>
(Active energy ray-curable compound No. 1: Cationic polymerizable compound)
Examples of the epoxy compound constituting the curable resin composition include glycidyl ether of a polyol having an alicyclic ring, an alicyclic epoxy compound, an aliphatic epoxy compound, and an aromatic epoxy compound.

The glycidyl ether of a polyol having an alicyclic ring is a compound obtained by converting the hydroxyl groups of a compound having at least two hydroxyl groups bonded to the alicyclic ring into glycidyl ether. A polyol having an alicyclic ring, that is, a compound having at least two hydroxyl groups bonded to the alicyclic ring in the molecule, selectively hydrogenates an aromatic polyol into the aromatic ring under pressure in the presence of a catalyst. Can be obtained by doing. Aromatic polyols are, for example, bisphenol compounds such as bisphenol A, bisphenol F and bisphenol S; novolac resins such as phenol novolac resin, cresol novolac resin and hydroxybenzaldehyde phenol novolac resin; tetrahydroxydiphenylmethane, tetrahydroxybenzophenone. And polyfunctional compounds such as polyvinylphenol. A glycidyl ether can be obtained by reacting an alicyclic polyol obtained by hydrogenating the aromatic rings of these aromatic polyols with epichlorohydrin. Among these, the diglycidyl ether of hydrogenated bisphenol A is preferable.

The alicyclic epoxy compound is a compound having at least one epoxy group bonded to the alicyclic ring in the molecule. The “epoxide group bonded to the alicyclic ring” means a bridging oxygen atom —O— in the structure represented by the following chemical formula (10), in which m is an integer of 2 to 5.

_{A compound in which one or a plurality of hydrogen atoms in (CH 2} ) _m in the above chemical formula (10) are removed and a group bonded to another chemical structure can be an alicyclic epoxy compound. _{One or more hydrogen atoms in (CH 2} ) _m forming an alicyclic ring may be appropriately substituted with a linear alkyl group such as a methyl group or an ethyl group. Among the alicyclic epoxy compounds, the epoxy compounds having an epoxycyclopentane ring (m = 3 in the above formula) and an epoxycyclohexane ring (m = 4 in the above formula) are cured products. Is more preferably used because of its high elastic modulus and excellent adhesion to the polarizer 10.

Specific examples of alicyclic epoxy compounds are listed below. In the following, the compound names are first listed, and then the chemical formulas corresponding to each compound name are shown. The same code is attached to the compound name and the corresponding chemical formula.

A: 3,4-Epoxycyclohexylmethyl 3,4-epoxycyclohexanecarboxylate,
B: 3,4-Epoxy-6-methylcyclohexylmethyl 3,4-epoxy-6-methylcyclohexanecarboxylate,
C: Ethylene bis (3,4-epoxycyclohexanecarboxylate),
D: Bis (3,4-epoxycyclohexylmethyl) adipate,
E: Bis (3,4-epoxy-6-methylcyclohexylmethyl) adipate,
F: Diethylene glycol bis (3,4-epoxycyclohexylmethyl ether), G: Ethylene glycol bis (3,4-epoxycyclohexylmethyl ether),
H: 2,3,14,15-Diepoxy-7,11,18,21-Tetraoxatrispyro [5.2.2.5.2.2] Heneicosane,
I: 3- (3,4-epoxycyclohexyl) -8,9-epoxy-1,5-dioxaspiro [5.5] undecane,
J: 4-Vinylcyclohexene dioxide,
K: Limonene Geoxide,
L: Vis (2,3-epoxycyclopentyl) ether,
M: Dicyclopentadiene dioxide, etc.

The aliphatic epoxy compound can be an aliphatic polyhydric alcohol or a polyglycidyl ether of an alkylene oxide adduct thereof. The aliphatic epoxy compounds include, for example, diglycidyl ether of 1,4-butanediol, diglycidyl ether of 1,6-hexanediol, triglycidyl ether of glycerin, triglycidyl ether of trimethylolpropane, and diglycidyl of polyethylene glycol. Ether, diglycidyl ether of propylene glycol, polyglycidyl ether of polyether polyol obtained by adding alkylene oxide (ethylene oxide or propylene oxide) to aliphatic polyhydric alcohol such as ethylene glycol, propylene glycol and glycerin. ..

From the viewpoint of improving the adhesiveness between the resin layer 11 and the first pressure-sensitive adhesive layer 15, the aliphatic epoxy compound contained in the curable resin composition has two oxylan rings bonded to the aliphatic carbon atom in the molecule. It is preferably a bifunctional epoxy compound (aliphatic diepoxy compound) having the above. When the curable resin composition contains an aliphatic diepoxy compound, a curable resin composition having a low viscosity and easy to apply can be obtained.

Aromatic epoxy compounds are compounds that have one or more aromatic rings in the molecule. Specific examples of aromatic epoxy compounds are listed below.
A monovalent phenol having at least one aromatic ring such as phenol, cresol, butylphenol, or a mono / polyglycidyl etherified product of an alkylene oxide adduct thereof, for example, bisphenol A, bisphenol F, or a compound obtained by further adding an alkylene oxide to these. Glycidyl etheric compounds and epoxy novolac resins;
Glycidyl ether, an aromatic compound having two or more phenolic hydroxyl groups such as resorcinol, hydroquinone, and catechol;
Mono / polyglycidyl etherified product of an aromatic compound having two or more alcoholic hydroxyl groups such as benzenedimethanol, benzenediethanol, and benzenedibutanol;
Glycidyl ester of a polybasic acid aromatic compound having two or more carboxylic acids such as phthalic acid, terephthalic acid, trimellitic acid;
Glycidyl esters of benzoic acids such as benzoic acid, toluic acid, and naphthoic acid;
Epoxy of styrene oxide or divinylbenzene, etc.

From the viewpoint of reducing the viscosity of the curable composition, the aromatic epoxy compounds include glycidyl ethers of phenols, glycidyl etherified products of aromatic compounds having two or more alcoholic hydroxyl groups, glycidyl etherified products of polyhydric phenols, and benzo. It preferably contains at least one selected from the group consisting of glycidyl esters of acids, glycidyl esters of polybasic acids, styrene oxides or epoxidized compounds of divinylbenzene. Further, since the curability of the curable composition is improved, the aromatic epoxy compound preferably has an epoxy equivalent of 80 to 500. One kind of aromatic epoxy compound may be used alone, or a plurality of different kinds of aromatic epoxy compounds may be used in combination.

As the aromatic epoxy compound, a commercially available product can be used. The trade names of commercially available aromatic epoxy compounds are, for example, Denacol EX-121, Denacol EX-141, Denacol EX-142, Denacol EX-145, Denacol EX-146, Denacol EX-147, Denacol EX-201, and Denacol. EX-203, Denacol EX-711, Denacol EX-721, On-Coat EX-1020, On-Coat EX-1030, On-Coat EX-1040, On-Coat EX-1050, On-Coat EX-1051, On-Coat EX-1010, On-Coat EX-1011, On-Coat 1012 (above, manufactured by Nagase Chemtex); Ogsol PG-100, Ogsol EG-200, Ogsol EG-210, Ogsol EG-250 (above, manufactured by Osaka Gas Chemical Co., Ltd.); HP4032, HP4032D, HP4700 (above, manufactured by DIC Corporation); ESN-475V (manufactured by Nippon Steel & Sumitomo Metal Corporation); Epicoat YX8800 (manufactured by Mitsubishi Chemical Corporation); Marproof G-0105SA, Marproof G-0130SP (manufactured by Nippon Oil Co., Ltd.); N-665, Epicron HP-7200 (all manufactured by DIC Corporation); EOCN-1020, EOCN-102S, EOCN-103S, EOCN-104S, XD-1000, NC-3000, EPPN-501H, EPPN-501HY, EPPN- 502H, NC-7000L (manufactured by Nippon Kayaku Co., Ltd.); ADEKA Glycyllol ED-501, ADEKA Glycyllol ED-502, ADEKA Glycyrrol ED-509, ADEKA Glycyrrol ED-529, ADEKA REGIN EP-4000, ADEKA REGIN EP -4005, ADEKA REGIN EP-4100, ADEKA RESIN EP-4901 (above, manufactured by ADEKA); TECHMORE VG-3101L, EPOX-MKR710, EPOX-MKR151 (above, manufactured by Printec) and the like.

When the curable resin composition contains an aromatic epoxy compound, the curable resin composition becomes a hydrophobic resin, and the cured product layer (resin layer 11) obtained thereby can also have hydrophobicity. As a result, the invasion of water from the outside into the polarizing plate is suppressed under high temperature and high humidity, and the movement of the dichroic dye (iodine) contained in the polarizing element 10 is effectively suppressed.

In the curable resin composition, the epoxy compounds may be used alone or in combination of two or more. Since the resin layer 11 having excellent adhesion to the polarizer 10 can be obtained, the curable resin composition preferably contains at least an alicyclic epoxy compound.

The content of the epoxy compound may be 30 to 100% by weight, preferably 35 to 70% by weight, and more preferably 40 to 60% by weight based on the total amount of the active energy ray-curable compound. When the content of the epoxy compound is less than 30% by weight, the adhesion to the polarizer 10 tends to decrease.

Further, the curable resin composition may contain an oxetane-based compound in addition to the above-mentioned epoxy-based compound. By adding the oxetane compound, the viscosity of the curable resin composition can be lowered and the curing rate can be increased. Further, it is expected to have an effect of preventing yellowing of the cured film and improving optical durability.

The oxetane compound is a compound having a 4-membered ring ether in the molecule. Oxetane compounds include, for example, 3-ethyl-3-hydroxymethyloxetane, 1,4-bis [(3-ethyl3-oxetanyl) methoxymethyl] benzene, 3-ethyl-3- (phenoxymethyl) oxetane, bis ( 3-Ethyl-3-oxetanylmethyl) ether, 3-ethyl-3- (2-ethylhexyloxymethyl) oxetane, phenol novolac oxetane and the like. Commercially available products of these oxetane compounds can be easily obtained. For example, the trade names of oxetane compounds sold by Toa Synthetic Co., Ltd. are "Aron Oxetane OXT-101", "Aron Oxetane OXT-121", "Aron Oxetane OXT-221", and "Aron Oxetane OXT-221". , "Aron Oxetane OXT-212" and the like. The blending amount of the oxetane-based compound is not particularly limited, but may be 70% by weight or less, preferably 10 to 50% by weight, based on the total amount of the active energy ray-curable compound.

The composition of the curable resin composition is based on 100% by mass of the total amount of the polymerizable compound (the entire curable resin composition).
(A1) 35 to 70% by mass of an oxetane compound having two or more oxetanyl groups,
(A2) 0-40% by mass of an aliphatic epoxy compound having two or more epoxy groups,
(A3) 15 to 50% by mass of an alicyclic epoxy compound having two or more epoxy groups, and (A4) 0 to 20% by mass of an aromatic epoxy compound having one or more aromatic rings.
Is preferable.
When the curable resin composition contains the oxetane compound (A) and the alicyclic epoxy compound (B1), the content of the alicyclic epoxy compound (B1) relative to the content (WA) of the oxetane compound (A) ( The mass ratio (WB1 / WA) of WB1) is preferably 0.05 to 1.5.
When the curable resin composition contains the oxetane compound (A) and the aliphatic epoxy compound (B2), the content of the aliphatic epoxy compound (B2) relative to the content (WA) of the oxetane compound (A) (WB2). The mass ratio (WB2 / WA) of is preferably 0.1 to 0.5.
When the curable resin composition contains the oxetane compound (A) and the aromatic epoxy compound (B3), the content of the aromatic epoxy compound (B3) relative to the content (WA) of the oxetane compound (A) (WB3). The mass ratio (WB3 / WA) of is preferably 0.1 to 1.5.

(Polymer Initiator Part 1: Photocationic Polymerization Initiator)
When the curable resin composition contains a cationically polymerizable compound such as an epoxy compound or an oxetane compound, it is preferable to add a photocationic polymerization initiator to the curable resin composition. Since the resin layer 11 can be formed at room temperature by using the photocationic polymerization initiator, it is less necessary to consider the heat resistance of the polarizer 10 and the strain due to expansion, and the resin layer 11 is formed on the polarizer 10. Is easy to adhere. Further, since the photocationic polymerization initiator acts catalytically with light, it is excellent in storage stability and workability even when mixed with a curable resin composition.

The photocationic polymerization initiator generates a cationic species or Lewis acid by irradiation with active energy rays such as visible light, ultraviolet rays, X-rays, and electron beams, and initiates a polymerization reaction of an epoxy compound and / or an oxetane compound. It is something that makes you. From the viewpoint of workability, it is preferable that the photocationic polymerization initiator has a potential. Photocationic polymerization initiators include, for example, aromatic diazonium salts; onium salts such as aromatic iodonium salts and aromatic sulfonium salts; iron-allene complexes.

Specific examples of the aromatic diazonium salt are as follows.
Benzenediazonium hexafluoroantimonate,
Benzenediazonium hexafluorophosphate,
Benzenediazonium hexafluoroborate, etc.

Specific examples of the aromatic iodonium salt are as follows.
Diphenyliodonium tetrakis (pentafluorophenyl) borate,
Diphenyliodonium hexafluorophosphate,
Diphenyliodonium hexafluoroantimonate,
Bis (4-nonylphenyl) iodonium hexafluorophosphate, etc.

Specific examples of the aromatic sulfonium salt are as follows.
Triphenylsulfonium hexafluorophosphate,
Triphenylsulfonium hexafluoroantimonate,
Triphenylsulfonium tetrakis (pentafluorophenyl) borate,
4,4'-Bis (diphenylsulfonio) diphenylsulfide bishexafluorophosphate,
4,4'-Bis [di (β-hydroxyethoxy) phenylsulfonio] diphenylsulfide bishexafluoroantimonate,
4,4'-Bis [di (β-hydroxyethoxy) phenylsulfonio] diphenylsulfide bishexafluorophosphate,
7- [Di (p-toluyl) sulfonio] -2-isopropylthioxanthone hexafluoroantimonate,
7- [di (p-toluyl) sulfonio] -2-isopropylthioxanthone tetrakis (pentafluorophenyl) borate,
4-Phenylcarbonyl-4'-diphenylsulfoniodiphenylsulfide hexafluorophosphate,
4- (p-tert-Butylphenylcarbonyl) -4'-diphenylsulfoniodiphenylsulfide hexafluoroantimonate,
4- (p-tert-Butylphenylcarbonyl) -4'-di (p-toluyl) sulfoniodiphenylsulfide tetrakis (pentafluorophenyl) borate and the like.

In addition, examples of the iron-arene complex include the following compounds.
Xylene-Cyclopentadienyl Iron (II) Hexafluoroantimonate,
Cumene-Cyclopentadienyl Iron (II) Hexafluorophosphate,
Xylene-cyclopentadienyl iron (II) tris (trifluoromethylsulfonyl) metanide and the like.

Commercially available products of these photocationic polymerization initiators can be easily obtained. The trade names of the commercially available photocationic polymerization initiators are "Kayarad PCI-220" and "Kayarad PCI-620" [above, manufactured by Nippon Kayaku Co., Ltd.], "Adeka Optomer SP-150" and "Adeka Opt". Mar SP-170 "[above, made by ADEKA Corporation]," UVAURE 1590 "[made by Daicel Cytec Co., Ltd.]," CI-5102 "," CIT-1370 "," CIT-1682 "," CIP- 1866S "," CIP-2048S "and" CIP-2064S "[above, manufactured by Nippon Soda Corporation]," DPI-101 "," DPI-102 "," DPI-103 "," DPI-105 "," MPI-103 "," MPI-105 "," BBI-101 "," BBI-102 "," BBI-103 "," BBI-105 "," TPS-101 "," TPS-102 "," TPS- 103 ”,“ TPS-105 ”,“ MDS-103 ”,“ MDS-105 ”,“ DTS-102 ”and“ DTS-103 ”[above, manufactured by Midori Kagaku Co., Ltd.],“ UVI-6990 ”[Union Carbide], "PI-2074" [Rhodia], etc.

These photocationic polymerization initiators may be used alone or in combination of two or more. Among these, aromatic sulfonium salts in particular have ultraviolet absorption characteristics even in the wavelength region of 300 nm or more, so that a cured product having excellent curability, good mechanical strength, and good adhesion to the polarizer 10 can be obtained. Since it can be given, it is preferably used.

The blending amount of the photocationic polymerization initiator is 0.5 to 20 parts by weight, preferably 10 parts by weight or less, more preferably 10 parts by weight, based on 100 parts by weight of the total of the cationically polymerizable compound containing the epoxy compound and the oxetane compound. It may be 1 to 6 parts by weight. If the amount of the photocationic polymerization initiator blended is small, the curing tends to be insufficient, and the mechanical strength and the adhesion between the resin layer 11 and the polarizer 10 tend to be lowered. On the other hand, if the amount of the photocationic polymerization initiator is too large, the amount of ionic substances in the cured product increases, which increases the hygroscopicity of the cured product and may reduce the durability performance.

(Active energy ray-curable compound # 2: Radical polymerizable compound)
The curable resin composition used in the present invention contains, in addition to the above-mentioned cationically polymerizable compound such as an epoxy compound, a radically polymerizable compound that can be polymerized by irradiation with active energy rays in the presence of a polymerization initiator. You may. Further, the curable resin composition can also be composed by using only the radically polymerizable compound as the active energy ray-curable compound. As the radically polymerizable compound, a (meth) acrylic compound having at least one (meth) acryloyloxy group in the molecule is preferably used. The (meth) acrylic compound means that it may be either an acrylic acid ester or a methacrylic acid ester, and is also referred to as (meth) acryloyl, (meth) acrylate, (meth) acrylic acid and the like in the present specification. The "(meta)" of time has the same meaning.

The (meth) acrylic compound having at least one (meth) acryloyloxy group in the molecule includes a (meth) acrylate monomer having at least one (meth) acryloyloxy group in the molecule and a compound having a functional group. Includes (meth) acrylate oligomers obtained by reacting more than one species and having at least two (meth) acryloyloxy groups in the molecule. Hereinafter, these monomers and oligomers will be specifically described, but they can be used individually or in combination of two or more if desired. The combination of two or more kinds includes a combination of monomers and a combination of oligomers, and also includes a combination of one or more kinds of monomers and one kind or two or more kinds of oligomers.

The (meth) acrylate monomer includes a monofunctional (meth) acrylate monomer having one (meth) acryloyloxy group in the molecule, and a bifunctional (meth) acrylate monomer having two (meth) acryloyloxy groups in the molecule. And there are polyfunctional (meth) acrylate monomers having 3 or more (meth) acryloyloxy groups in the molecule.

Specific examples of the monofunctional (meth) acrylate monomer are as follows.
Tetrahydrofurfuryl (meth) acrylate,
2-Hydroxyethyl (meth) acrylate,
2- or 3-Hydroxypropyl (meth) acrylate,
2-Hydroxybutyl (meth) acrylate,
2-Hydroxy-3-phenoxypropyl (meth) acrylate,
Isobutyl (meth) acrylate,
tert-butyl (meth) acrylate,
2-Ethylhexyl (meth) acrylate,
Cyclohexyl (meth) acrylate,
Dicyclopentenyl (meth) acrylate,
Benzyl (meth) acrylate,
Isobornyl (meth) acrylate,
2-Phenoxyethyl (meth) acrylate,
Dicyclopentenyloxyethyl (meth) acrylate,
N, N-dimethyl-2-aminoethyl (meth) acrylate,
Ethyl carbitol (meth) acrylate,
Trimethylolpropane mono (meth) acrylate,
Pentaerythritol mono (meth) acrylate,
Phenoxy polyethylene glycol (meth) acrylate, etc.

Further, a compound having a carboxyl group in the molecule together with one (meth) acryloyloxy group can also be a monofunctional (meth) acrylate monomer. Specific examples of the monofunctional (meth) acrylate monomer having a carboxyl group are as follows.
2- (Meta) acryloyloxyethyl phthalic acid,
2- (Meta) acryloyloxyethyl hexahydrophthalic acid,
2-carboxyethyl (meth) acrylate,
2- (Meta) acryloyloxyethyl succinic acid,
4- (Meta) acryloyloxyethyl trimellitic acid, etc.

There are various bifunctional (meth) acrylate monomers. Typical bifunctional (meth) acrylate monomers are alkylene glycol di (meth) acrylates, polyoxyalkylene glycol di (meth) acrylates, halogen-substituted alkylene glycol di (meth) acrylates, and aliphatic polyol di (meth) acrylates. ) Di (meth) acrylates, hydrogenated dicyclopentadiene or tricyclodecane dialkanol di (meth) acrylates, di (meth) acrylates of dioxane glycol or dioxan dialkanol, di (meth) acrylates of bisphenol A or bisphenol F alkylene oxide adducts. Meta) acrylates, bisphenol A or bisphenol F epoxy di (meth) acrylates and the like.

Specific examples of the bifunctional (meth) acrylate monomer are as follows.
Ethylene glycol di (meth) acrylate,
1,3-Butanediol di (meth) acrylate,
1,4-Butanediol di (meth) acrylate,
1,6-Hexanediol di (meth) acrylate,
1,9-Nonanediol di (meth) acrylate,
Neopentyl glycol di (meth) acrylate,
Trimethylolpropane di (meth) acrylate,
Pentaerythritol di (meth) acrylate,
Ditrimethylolpropane di (meth) acrylate,
Diethylene glycol di (meth) acrylate,
Triethylene glycol di (meth) acrylate,
Dipropylene glycol di (meth) acrylate,
Tripropylene glycol di (meth) acrylate,
Polyethylene glycol di (meth) acrylate,
Polypropylene glycol di (meth) acrylate,
Polytetramethylene glycol di (meth) acrylate,
Di (meth) acrylate of hydroxypivalate neopentyl glycol ester,
2,2-Bis [4- {2- (2- (meth) acryloyloxyethoxy) ethoxy} phenyl] propane,
2,2-Bis [4- {2- (2- (meth) acryloyloxyethoxy) ethoxy} cyclohexyl] propane,
Hydrogenated dicyclopentadienyl di (meth) acrylate,
Tricyclodecanedimethanol di (meth) acrylate,
1,3-dioxane-2,5-diyldi (meth) acrylate [also known as dioxane glycol di (meth) acrylate],
Di (meth) of an acetal compound of hydroxypivalaldehyde and trimethylolpropane [chemical name: 2- (2-hydroxy-1,1-dimethylethyl) -5-ethyl-5-hydroxymethyl-1,3-dioxane] ) Acrylate,
Di (meth) acrylate of 1,3,5-tris (2-hydroxyethyl) isocyanurate.

There are various types of trifunctional or higher functional (meth) acrylate monomers. For example, poly (meth) acrylates of trivalent or higher aliphatic polyols are typical. Specific examples are as follows.
Glycerin tri (meth) acrylate,
Trimethylolpropane tri (meth) acrylate,
Ditrimethylolpropane Tri (meth) acrylate,
Ditrimethylolpropane tetra (meth) acrylate,
Pentaerythritol tri (meth) acrylate,
Pentaerythritol tetra (meth) acrylate,
Dipentaerythritol tetra (meth) acrylate,
Dipentaerythritol Penta (meth) acrylate,
Dipentaerythritol hexa (meth) acrylate, etc.

In addition, poly (meth) acrylates of halogen-substituted polyols of trivalent or higher, tri (meth) acrylates of alkylene oxide adducts of glycerin, tri (meth) acrylates of alkylene oxide adducts of trimethylolpropane, 1,1,1 -Tris [2- {2- (meth) acryloyloxyethoxy} ethoxy] propane, 1,3,5-tris [2- (meth) acryloyloxyethyl] isocyanurate, etc. can also be polyfunctional (meth) acrylate monomers. ..

On the other hand, the (meth) acrylate oligomer is, for example, a urethane (meth) acrylate oligomer, a polyester (meth) acrylate oligomer, an epoxy (meth) acrylate oligomer, or the like.

The urethane (meth) acrylate oligomer refers to a compound having at least two (meth) acryloyloxy groups in the molecule and having a urethane bond (-NHCOO-). The urethane (meth) acrylate oligomer is, for example, a urethanization reaction product of a hydroxyl group-containing (meth) acrylate monomer having at least one (meth) acryloyloxy group and one hydroxyl group in the molecule and polyisocyanate. It's okay. The urethane (meth) acrylate oligomer has, for example, a terminal isocyanato group-containing urethane compound obtained by reacting polyols with polyisocyanate, and at least one (meth) acryloyloxy group and one hydroxyl group in the molecule. It may be a urethanization reaction product with a hydroxyl group-containing (meth) acrylate monomer.

Specific examples of the hydroxyl group-containing (meth) acrylate monomer used in the urethanization reaction are as follows.
2-Hydroxyethyl (meth) acrylate,
2-Hydroxypropyl (meth) acrylate,
2-Hydroxybutyl (meth) acrylate,
2-Hydroxy-3-phenoxypropyl (meth) acrylate,
Glycerin di (meth) acrylate,
Trimethylolpropane di (meth) acrylate,
Pentaerythritol tri (meth) acrylate,
Dipentaerythritol Penta (meth) acrylate, etc.

Specific examples of the polyisocyanate subjected to the urethanization reaction with the hydroxyl group-containing (meth) acrylate monomer are as follows.
Hexamethylene diisocyanate,
Lysine diisocyanate,
Isophorone diisocyanate,
Dicyclohexylmethane diisocyanate,
Tolylene diisocyanate,
Xylylene diisocyanate,
Compounds obtained by hydrogenating aromatic diisocyanates, for example, hydrogenated tolylene diisocyanates, hydrogenated xylylene diisocyanates,
Triphenylmethane triisocyanate,
Dibenzylbenzene triisocyanate,
Polyisocyanates obtained by increasing the amount of diisocyanates among these.

Further, the polyols for producing the terminal isocyanato group-containing urethane compound by the reaction with the polyisocyanate may be an aliphatic or alicyclic polyol, a polyester polyol, a polyether polyol, or the like. The aliphatic and alicyclic polyols include, for example, 1,4-butanediol, 1,6-hexanediol, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, neopentyl glycol, trimethylolethane, trimethylolpropane, and the like. Ditrimethylolpropane, pentaerythritol, dipentaerythritol, dimethylolheptan, dimethylolpropionic acid, dimethylolbutyric acid, glycerin, hydrogenated bisphenol A and the like.

The polyester polyol is a compound obtained by dehydrating and condensing the above-mentioned polyols with a polybasic carboxylic acid or an anhydride thereof. Specific examples of polybasic carboxylic acids and their anhydrides are (succinic anhydride) succinic anhydride, adipic acid, (anhydrous) maleic acid, (anhydrous) isophthalic acid, (anhydrous) trimellitic acid, (anhydrous) pyromellitic acid, and hexahydro. There are (anhydrous) phthalic acid, (anhydrous) phthalic acid, isophthalic acid, terephthalic acid and the like. The polybasic carboxylic acid does not have to be anhydrous.

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

The polyester (meth) acrylate oligomer is a compound having at least two (meth) acryloyloxy groups in the molecule and having an ester bond. A polyester (meth) acrylate oligomer can be obtained by a dehydration condensation reaction of (meth) acrylic acid, a polybasic carboxylic acid or an anhydride thereof, and a polyol. Specific examples of the polybasic carboxylic acid or its anhydride used in the dehydration condensation reaction include (anhydrous) succinic anhydride, adipic acid, (anhydrous) maleic acid, (anhydrous) itaconic acid, (anhydrous) trimellitic acid, and (anhydrous). ) Pyromellitic acid, hexahydro (phthalic anhydride) phthalic acid, (phthalic anhydride) phthalic acid, isophthalic acid, terephthalic acid and the like. It does not have to be an anhydride of a polybasic carboxylic acid. Specific examples of the polyol used in the dehydration condensation reaction include 1,4-butanediol, 1,6-hexanediol, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, neopentyl glycol, trimethylolethane, and trimethylolpropane. , Ditrimethylolpropane, pentaerythritol, dipentaerythritol, dimethylolheptan, dimethylolpropionic acid, dimethylolbutyric acid, glycerin, hydrogenated bisphenol A and the like.

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

Among the above-mentioned (meth) acrylic compounds, at least one of the (meth) acrylic compounds represented by the following formulas (I) to (IV) has excellent adhesion and elastic modulus. Especially preferable.

In the above formula (I) and (II), Q ₁ and Q ₂ each independently represent a (meth) acryloyloxy group or (meth) acryloyloxy alkyl group. When Q ₁ or Q ₂ is a (meth) acryloyloxyalkyl group, the alkyl may be linear or branched and may have 1 to 10 carbon atoms, but is generally about 1 to 6 carbon atoms. The number of carbon atoms is sufficient. Further, in the formula (II), Q is hydrogen or a hydrocarbon group having 1 to 10 carbon atoms, and the hydrocarbon group may be linear or branched, and can be typically an alkyl group.
In this case, the number of carbon atoms of the alkyl group is also sufficient to be about 1 to 6.

On the other hand, in the above formula (III), R ₁ , R ₂ and R ₃ independently represent a (meth) acryloyloxy group, and in the formula (IV), R represents a hydroxyl group or a (meth) acryloyloxy group. ..

The compound represented by the formula (I) is a di (meth) acrylate derivative of hydrogenated dicyclopentadiene or tricyclodecanedialkanol. Specific examples of the compound represented by the formula (I) are hydrogenated dicyclopentadienyl di (meth) acrylate [in the formula (I), _{both Q 1} and Q ₂ are the same (meth) acryloyloxy group. compound] in tricyclodecane di (meth) acrylate [the formula (I), a compound both of Q ₁ and Q ₂ are the same (meth) acryloyloxy methyl group], and the like.

The compound represented by the formula (II) is a di (meth) acrylate derivative of dioxane glycol or dioxane dialkanol. Specific examples of the compound represented by formula (II), 1,3-dioxane-2,5-diyl di (meth) acrylate [alias: dioxane glycol di (meth) acrylate, in the formula (II), _{Q 1} and both Q ₂ 'are the same (meth) acryloyloxy group, compound and Q and H are the same], hydroxypivalaldehyde acetal compound of trimethylolpropane [chemical name: 2- (2-hydroxy - in 1,1-dimethylethyl) -5-ethyl-5-hydroxymethyl-1,3-dioxane] di (meth) acrylate [the formula (II), _{Q 1} is (meth) acryloyloxy methyl group, _{Q 2} is 2- (Meth) acryloyloxy-1,1-dimethylethyl group, Q is an ethyl group compound] and the like.

The compound represented by the formula (III) is a triacrylate or trimetaacrylate of 1,3,5-tris (2-hydroxyethyl) isocyanurate. The compound represented by the formula (IV) is pentaerythritol tri- or tetra- (meth) acrylate, and specific examples thereof are pentaerythritol tri (meth) acrylate and pentaerythritol tetra (meth) acrylate. ..

The (meth) acrylic compound is preferably used in combination with at least an epoxy compound. The content of the (meth) acrylic compound may be 70% by weight or less, preferably 35 to 70% by weight, and preferably 40 to 60% by weight, based on the total amount of the active energy ray-curable compound. When the content of the (meth) acrylic compound among the active energy ray-curable compounds exceeds 70% by weight, the adhesion to the polarizer 10 tends to decrease.

(Polymer Initiator # 2: Photoradical Polymerization Initiator)
When the active energy ray-curable compound contains a radically polymerizable compound such as a (meth) acrylic compound, it is preferable to add a photoradical polymerization initiator as the polymerization initiator. The photoradical polymerization initiator is not particularly limited as long as it can initiate curing of the radically polymerizable compound by irradiation with active energy rays, and conventionally known ones can be used. Specific examples of photoradical initiators include acetophenone, 3-methylacetophenone, benzyldimethylketal, 1- (4-isopropylphenyl) -2-hydroxy-2-methylpropan-1-one, 2-methyl-1-[. Acetphenone-based initiators such as 4- (methylthio) phenyl] -2-morpholinopropane-1-one and 2-hydroxy-2-methyl-1-phenylpropan-1-one; benzophenone, 4-chlorobenzophenone and 4, Benzophenone-based initiators such as 4'-diaminobenzophenone; benzoin ether-based initiators such as benzoin propyl ether and benzoin ethyl ether; thioxanthone-based initiators such as 4-isopropylthioxanthone; Benzaldehyde, anthraquinone, etc.

The blending amount of the photoradical polymerization initiator is 0.5 to 20 parts by weight, preferably 10 parts by weight or less, more preferably 1 to 1 to 100 parts by weight, based on 100 parts by weight of the radically polymerizable compound such as a (meth) acrylic compound. It may be 6 parts by weight. If the amount of the photoradical polymerization initiator is small, the curing tends to be insufficient, and the mechanical strength and the adhesion between the resin layer 11 and the polarizer 10 tend to decrease. On the other hand, if the amount of the photoradical polymerization initiator is too large, the amount of the active energy ray-curable compound in the curable resin composition is relatively small, and the durability performance of the resin layer 11 may be deteriorated.

The curable resin composition can further contain a photosensitizer, if necessary. By using the photosensitizer, the reactivity of cationic polymerization and / or radical polymerization can be improved, and the mechanical strength of the resin layer 11 and the adhesion between the resin layer 11 and the polarizer 10 can be improved. The photosensitizer is, for example, a carbonyl compound, an organic sulfur compound, a persulfide compound, a redox compound, an azo compound, a diazo compound, a halogen compound, a photoreducing dye and the like. Photosensitizers are benzoin methyl ethers, benzoin isopropyl ethers and benzoin derivatives such as α, α-dimethoxy-α-phenylacetophenone; benzophenone, 2,4-dichlorobenzophenone, methyl o-benzoyl benzoate, 4,4'. -Benzophenone derivatives such as bis (dimethylamino) benzophenone and 4,4'-bis (diethylamino) benzophenone; thioxanthone derivatives such as 2-chlorothioxanthone and 2-isopropylthioxanthone; such as 2-chloroanthraquinone and 2-methylanthraquinone. Anthraquinone derivatives; acridone derivatives such as N-methylacridone and N-butylacridone; other compounds such as α, α-diethoxyacetophenone, benzyl, fluorenone, xanthone, and uranyl compounds. Each of these photosensitizers may be used alone, or two or more kinds of photosensitizers may be mixed and used. The content of the photosensitizer may be 0.1 to 20 parts by weight with respect to 100 parts by weight of the entire active energy ray-curable compound.

(Optional component of curable resin composition)
Further, the curable resin composition may contain an antistatic agent for imparting antistatic performance to the polarizing plate. The antistatic agent is, for example, a cationic surfactant, an anionic surfactant, a nonionic surfactant, an ionic compound having an organic cation other than the cationic surfactant, and an ion having an organic anion other than the anionic surfactant. It may be a sex compound, a conductive inorganic particle, a conductive polymer, or the like. The blending ratio of these antistatic agents is appropriately determined according to the desired characteristics. The blending ratio of the antistatic agent may be about 0.1 to 20 parts by weight, with 100 parts by weight of the entire active energy ray-curable compound.

The curable resin composition can also contain additives usually used for polymer materials. For example, primary antioxidants such as phenolic and amine-based, sulfur-based secondary antioxidants, hindered amine-based photostabilizers (HALS), benzophenone-based, benzotriazole-based, and ultraviolet absorbers such as benzoate-based ultraviolet absorbers. Can be mentioned.

A leveling agent can also be added to the curable resin composition. When the curable resin composition is applied onto the polarizer 10 or the base film, if the applicability to the polarizer 10 or the substrate film is poor, or if the surface property of the cured product is poor, a leveling agent is used. By blending, these problems can be improved. The leveling agent may be a silicone-based leveling agent, a fluorine-based leveling agent, a polyether-based leveling agent, an acrylic acid copolymer-based leveling agent, or a titanate-based leveling agent. These leveling agents may be used alone or in combination of two or more. The blending ratio of the leveling agent is 0.01 to 1 part by weight, preferably 0.1 to 0.7 parts by weight, and more preferably 0.2 to 0.5 parts by weight with respect to 100 parts by weight of the active energy ray-curable compound. It may be a part by weight. If the amount of the leveling agent blended is small, it is difficult to sufficiently exert the effect of improving the coatability and surface properties. On the other hand, if the blending amount is too large, the adhesion between the polarizer 10 and the resin layer 11 may be lowered.

Further, the curable resin composition may contain fine particles, for example, silica fine particles. By blending fine particles, particularly silica fine particles, the hardness and mechanical strength of the obtained resin layer 11 can be further improved. The silica fine particles can be blended in the curable resin composition as, for example, a liquid material dispersed in an organic solvent. When silica fine particles dispersed in an organic solvent are used, the silica concentration in the organic solvent may be, for example, about 20 to 40% by weight.

The silica fine particles may have a reactive functional group such as a hydroxyl group, an epoxy group, a (meth) acryloyl group, or a vinyl group on the surface thereof. The particle size of the silica fine particles may be usually 100 nm or less, preferably about 5 to 50 nm. When the particle size of the fine particles exceeds 100 nm, it tends to be difficult to obtain the optically transparent resin layer 11.

The blending ratio of the silica fine particles may be 5 to 250 parts by weight, preferably 10 to 100 parts by weight, based on 100 parts by weight of the active energy ray-curable compound. If the amount of the fine particles blended is small, the effect of improving the hardness of the resin layer 11 due to the addition thereof is difficult to be sufficiently exhibited. On the other hand, if the amount of the fine particles blended is too large, the adhesion between the polarizer 10 and the resin layer 11 may be lowered, the dispersion stability of the fine particles in the curable resin composition may be lowered, or the curing thereof may be lowered. The viscosity of the sex resin composition may be excessively increased.

The curable resin composition may contain a solvent if necessary. The solvent is appropriately selected depending on the solubility of the components constituting the curable resin composition. Solvents are aliphatic hydrocarbons such as n-hexane and cyclohexane; aromatic hydrocarbons such as toluene and xylene; alcohols such as methanol, ethanol, propanol, isopropanol and butanol; acetone, methyl ethyl ketone, methyl isobutyl. Ketones such as ketones and cyclohexanones; esters such as methyl acetate, ethyl acetate and butyl acetate; cellosolves such as methyl cellosolves, ethyl cellosolves and butyl cellosolves; halogenated hydrocarbons such as methylene chloride and chloroform. be. The mixing ratio of the solvent is appropriately determined from the viewpoint of adjusting the viscosity for processing purposes such as film forming property.

The curable resin composition may be formed from an aqueous solution of an active energy ray-curable compound in which the main solvent is water. As such a curable resin composition, for example, an active energy ray-curable polymer composition containing a polymer compound having an ethylenically unsaturated group as a main component, as described in JP-A-2017-75986. An aqueous solution of the material is preferably used.

The thickness of the resin layer 11 may be, for example, 0.5 μm or more and 20 μm or less, 1 μm or more and 10 μm or less, or 1 μm or more and 5 μm or less. When the thickness of the resin layer 11 is not more than the above upper limit value, the curable composition can be sufficiently cured.

(4) Adhesive Layer The protective film 12 can be attached to the polarizer 10 via, for example, an adhesive layer or an adhesive layer which is an adhesive layer. Further, when two or more protective films are provided between the polarizer 10 and the high retardation film 13, the protective films are bonded to each other via, for example, an adhesive layer or an adhesive layer which is an adhesive layer. Can be. As the adhesive forming the adhesive layer, a water-based adhesive, an active energy ray-curable adhesive or a thermosetting adhesive can be used, and a water-based adhesive or an active energy ray-curable adhesive is preferable. As the pressure-sensitive adhesive layer, those described later can be used.

Examples of the water-based adhesive include an adhesive composed of a polyvinyl alcohol-based resin aqueous solution, a water-based two-component urethane-based emulsion adhesive, and the like. Of these, a water-based adhesive composed of an aqueous solution of a polyvinyl alcohol-based resin is preferably used. Examples of the polyvinyl alcohol-based resin include vinyl alcohol homopolymers obtained by saponifying polyvinyl acetate, which is a homopolymer of vinyl acetate, and co-polymers of vinyl acetate and other monomers copolymerizable therewith. A polyvinyl alcohol-based copolymer obtained by saponifying the polymer, or a modified polyvinyl alcohol-based polymer in which the hydroxyl groups thereof are partially modified can be used. The water-based adhesive may contain a cross-linking agent such as an aldehyde compound (glioxal or the like), an epoxy compound, a melamine compound, a methylol compound, an isocyanate compound, an amine compound, or a polyvalent metal salt.

When a water-based adhesive is used, it is preferable to carry out a drying step for removing water contained in the water-based adhesive after the polarizer and the protective film are bonded together. After the drying step, a curing step of curing at a temperature of, for example, 20 to 45 ° C. may be provided.

The active energy ray-curable adhesive is an adhesive containing a curable compound that is cured by irradiation with active energy rays such as ultraviolet rays, visible light, electron beams, and X-rays, and is preferably an ultraviolet curable adhesive. Is.

The curable compound can be a cationically polymerizable curable compound or a radically polymerizable curable compound. Examples of the cationically polymerizable curable compound include an epoxy compound (a compound having one or more epoxy groups in the molecule) and an oxetane compound (one or two or more oxetane rings in the molecule). Compounds), or a combination thereof. Examples of the radically polymerizable curable compound include a (meth) acrylic compound (a compound having one or more (meth) acryloyloxy groups in the molecule) and a radically polymerizable double bond. Other vinyl compounds or combinations thereof can be mentioned. A cationically polymerizable curable compound and a radically polymerizable curable compound may be used in combination. The active energy ray-curable adhesive usually further contains a cationic polymerization initiator and / or a radical polymerization initiator for initiating the curing reaction of the curable compound.

When bonding the polarizer and the protective film, or when bonding the protective film and the protective film, in order to improve the adhesiveness, at least one of these bonding surfaces is subjected to a surface activation treatment. You may. Surface activation treatment includes dry treatment such as corona treatment, plasma treatment, discharge treatment (glow discharge treatment, etc.), flame treatment, ozone treatment, UV ozone treatment, ionization active ray treatment (ultraviolet ray treatment, electron beam treatment, etc.). Wet treatments such as ultrasonic treatment using a solvent such as water or acetone, saponification treatment, and anchor coating treatment can be mentioned. These surface activation treatments may be performed alone or in combination of two or more.

In the optical laminate of the present invention, the high retardation film 13 may be directly laminated on the polarizer 10 via the pressure-sensitive adhesive layer 14. In that case, the protective film 12 can be omitted.

<High retardation film 13>
The optical laminate of the present invention has a high retardation film 13 to ensure visibility through polarized sunglasses. The high retardation film 13 is made of a transparent thermoplastic resin film having birefringence. The in-plane retardation value Re [550] of the high retardation film 13 at a wavelength of 550 nm is preferably 3000 nm or more, more preferably 5000 nm or more, and particularly preferably 7000 nm or more. The upper limit of the in-plane retardation Re [550] of the high retardation film 13 is 30,000 nm. By using such a film, it is possible to suppress a hue change according to a viewing angle when the liquid crystal display device is visually recognized through polarized sunglasses.

The high retardation film 13 can be obtained, for example, by stretching a thermoplastic resin film. That is, the high retardation film 13 can be a stretched film. Specific thermoplastic resins 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 acid and poly (meth). (Meta) acrylic acid-based resins such as methyl acrylate; cellulose ester-based resins such as triacetyl cellulose, diacetyl cellulose and cellulose acetate propionate; vinyl alcohol-based resins such as polyvinyl alcohol and polyvinyl acetate; polycarbonate resins; polystyrene Based resin; Polyarylate type resin; Polysulfone type resin; Polyethersulfone type resin; Polyamide type resin; Polyimide type resin; Polyetherketone type resin; Polyphenylene sulfide type resin; Polyphenylene oxide type resin, and mixtures and copolymers thereof. And so on. From the viewpoint of availability and transparency, polyethylene terephthalate, cellulose ester, cyclic olefin resin or polycarbonate is preferable.

A film having a desired retardation value may be obtained by subjecting these thermoplastic resins to uniaxial or biaxial thermal stretching treatment. The stretching ratio is usually 1.1 to 6 times, preferably 1.1 to 4 times.

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

The angle formed by the slow axis of the high retardation film 13 and the absorption axis of the polarizer 10 is 40 ° to 50 °, more preferably 42 ° to 48 °, and particularly preferably about 45 °. About 45 ° means 44 ° to 46 °. As a result, it is possible to suppress a decrease in front luminance when the liquid crystal display device is visually recognized through polarized sunglasses.

The thickness of the high retardation film 13 is preferably 200 μm or less, more preferably 150 μm or less, and particularly preferably 100 μm or less. By setting the thickness of the high retardation film 13 to 200 μm or less, curling of the optical laminate 100 can be suppressed, and problems such as bubbles entering when the high retardation film 13 is attached to the liquid crystal display device can be suppressed.

By providing the optical laminate 100 on the viewer side of the liquid crystal cell of the liquid crystal display device, it is possible to suppress a decrease in visibility when the liquid crystal display device is visually recognized through polarized sunglasses without the need for another high-phase difference film. can do. Specifically, it is possible to suppress a decrease in front luminance and a change in hue (color shift) according to a viewing angle. A hard coat layer or an antiglare layer may be laminated on the high retardation film 13 as needed.

<First adhesive layer>
The first pressure-sensitive adhesive layer 15 is in contact with the surface of the polarizer 10 (see FIG. 1), or is in contact with the resin layer 11 when the resin layer 11 is provided on the surface of the polarizer 10 (FIG. 2). See) Provided. With such a configuration, it is possible to suppress the occurrence of light leakage even when stored in a high temperature environment for a long time. The reason why it is possible to suppress the occurrence of light leakage even when stored in a high temperature environment for a long time by such a configuration is that a resin film such as a protective film is inserted between the polarizer 10 and the first pressure-sensitive adhesive layer 15. It is presumed that this is because even if the residual stress in the oblique direction of the high retardation film 13 is released, it is possible to suppress the occurrence of the retardation in the specific resin film due to the residual stress.

In the optical laminate, the first pressure-sensitive adhesive layer 15 is bonded to the surface of the image display element on the visual side to form a display device. The first pressure-sensitive adhesive layer 15 can be composed of a pressure-sensitive adhesive composition containing a resin as a main component, such as (meth) acrylic-based, rubber-based, urethane-based, ester-based, silicone-based, and polyvinyl ether-based. Among them, a pressure-sensitive adhesive composition using a (meth) acrylic resin having excellent transparency, weather resistance, heat resistance and the like as a base polymer is preferable. The pressure-sensitive adhesive composition may be an active energy ray-curable type or a thermosetting type.

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

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

The storage elastic modulus of the first pressure-sensitive adhesive layer 15 is preferably 0.001 to 0.350 MPa, more preferably 0.001 to 0.200 MPa, and further 0.001 to 0.100 MPa at a frequency of 1 Hz and a temperature of 23 ° C. Preferably, 0.010 to 0.100 MPa is particularly preferable. The storage modulus is measured by the method described in Examples below.

The thickness of the first pressure-sensitive adhesive layer 15 is preferably 5 to 200 μm, more preferably 7 to 100 μm, further preferably 8 to 80 μm, and particularly preferably 10 to 50 μm.

<Second adhesive layer>
As the second pressure-sensitive adhesive layer 14, the one having the above-mentioned composition, characteristics, and thickness described as the first pressure-sensitive adhesive layer 15 can be used, and may be the same as or different from the first pressure-sensitive adhesive layer 15. May be.

<Front plate>
The

optical laminates

100 and 200 may be used with a front plate arranged on the visible side surface of the high retardation film 13. The front plate can be laminated on the visible side surface of the high retardation film 13 via an adhesive layer. Examples of the adhesive layer include the above-mentioned adhesive layer and adhesive layer.

Examples of the front plate include those having a hard coat layer on at least one surface of glass or a resin film. As the glass, for example, highly transparent glass or tempered glass can be used. Especially when a thin transparent surface material is used, chemically strengthened glass is preferable. The thickness of the glass can be, for example, 100 μm to 5 mm.

The front plate having a hard coat layer on at least one surface of the resin film can have flexible characteristics instead of being rigid like existing glass. The thickness of the hard coat layer is not particularly limited and may be, for example, 5 to 100 μm.

As the resin film, cycloolefin-based derivatives having a unit of a monomer containing cycloolefin such as norbornene or polycyclic norbornene-based monomer, cellulose (diacetyl cellulose, triacetyl cellulose, acetyl cellulose butyrate, isobutyl ester cellulose). , Propionyl cellulose, butyryl cellulose, acetylpropionyl cellulose) ethylene-vinyl acetate copolymer, polycycloolefin, polyester, polystyrene, polyamide, polyetherimide, polyacrylic, polyimide, polyamideimide, polyethersulfone, polysulfone, polyethylene, Polypropylene, polymethylpentene, polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, polyvinyl acetal, polyether ketone, polyether ether ketone, polyether sulfone, polymethyl methacrylate, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polycarbonate , Polyethylene, a film made of a polymer such as epoxy. As the resin film, an unstretched uniaxial or biaxially stretched film can be used. Each of these polymers can be used alone or in combination of two or more. As the resin film, a polyamideimide film or a polyimide film having excellent transparency and heat resistance, a uniaxial or biaxially stretched polyester film, a cycloolefin derivative film having excellent transparency and heat resistance and capable of adapting to a large size of the film. , Polymethylmethacrylate films and triacetylcellulose and isobutylester cellulose films that are transparent and not optically anisotropic are preferred. The thickness of the resin film may be 5 to 200 μm, preferably 20 to 100 μm.

The hard coat layer can be formed by curing a hard coat composition containing a reactive material that forms a crosslinked structure by irradiating light or heat energy. The hard coat layer can be formed by curing a hard coat composition containing a photocurable (meth) acrylate monomer, or an oligomer and a photocurable epoxy monomer, or an oligomer at the same time. The photocurable (meth) acrylate monomer may contain one or more selected from the group composed of epoxy (meth) acrylate, urethane (meth) acrylate and polyester (meth) acrylate. The epoxy (meth) acrylate can be obtained by reacting an epoxy compound with a carboxylic acid having a (meth) acryloyl group.

The hard coat composition can further contain one or more selected from the group consisting of solvents, photoinitiators and additives. Additives can include one or more selected from the group consisting of inorganic nanoparticles, leveling agents and stabilizers, and other components commonly used in the art, such as anti. Excipients, UV absorbers, surfactants, lubricants, antifouling agents and the like can be further included.

<Cushioning layer>
The

optical laminates

100 and 200 may have a buffer layer provided between the high retardation film 13 and the polarizing plate 1. By having a buffer layer, light leakage can be further suppressed even when placed in a high temperature environment.

The buffer layer is preferably laminated on the high retardation film 13 and the polarizing plate 1 via the pressure-sensitive adhesive layer. For example, the buffer layer can be laminated on the high retardation film 13 via the second pressure-sensitive adhesive layer 14, and can be laminated on the polarizing plate 1 via the third pressure-sensitive adhesive layer. By incorporating a buffer layer via the pressure-sensitive adhesive layer, light leakage can be further suppressed even after being placed in a high temperature environment. As the third pressure-sensitive adhesive layer 14, the above-mentioned composition, characteristics, and thickness described as the first pressure-sensitive adhesive layer 15 can be used, and may be the same as or different from the first pressure-sensitive adhesive layer 15. good.

The thickness of the buffer layer is preferably 20 μm or more, more preferably 25 μm or more, further preferably 30 μm or more, and usually 80 μm or less, 70 μm or less, 60 μm or less. There may be. The tensile elastic modulus at a temperature of the buffer layer of 23 ° C. and a relative humidity of 55% is preferably 1.5 GPa or more. The tensile elastic modulus of the buffer layer may be 3 GPa or more, 5 GPa or more, usually 10 GPa or less, and 8 GPa or less.

A resin film is exemplified as the buffer layer as described above. When the buffer layer is a resin film, the resin material (resin) constituting the resin film is preferably excellent in transparency, mechanical strength, thermal stability, moisture shielding property, stability of retardation value, and the like. The resin material is preferably a thermoplastic resin. Such a resin material is not particularly limited, and is, for example, a cellulose ester resin; a (meth) acrylic acid resin; an olefin resin such as a chain aliphatic olefin resin or a cyclic olefin resin; a polyvinyl chloride resin. Resin; styrene resin; acrylonitrile / butadiene / styrene resin; acrylonitrile / styrene resin; polyvinyl acetate resin; polyvinylidene chloride resin; polyamide resin; polyacetal resin; polycarbonate resin; modified polyphenylene ether resin; Polybutylene teflate-based resin, polyester-based resin such as polyethylene teftalate-based resin; polysulfone-based resin; polyether sulfone-based resin; polyarylate-based resin; polyamideimide-based resin; polyimide-based resin, etc. Species or a combination of two or more species can be used. Among them, it is preferable to use a resin selected from a cellulose ester resin, a (meth) acrylic acid resin, and a cyclic olefin resin. As used herein, the term "(meth) acrylic" means that it may be either acrylic or methacryl. (Meta) "(Meta)" such as acryloyl has the same meaning.

The resin material constituting the resin film can be used after performing any appropriate polymer modification, and the polymer modification includes, for example, copolymerization, cross-linking, molecular terminalization, stereoregularity control, and dissimilar polymers. Modifications such as mixing, including cases involving a reaction, can be mentioned.

In the cellulose ester-based resin, a part or all of hydrogen atoms in the hydroxyl group of cellulose obtained from raw material cellulose such as cotton linter and wood pulp (perforated tree pulp, coniferous tree pulp) are replaced with acetyl group, propionyl group and / or butyryl group. In addition, it is a cellulose organic acid ester or a cellulose mixed organic acid ester. For example, those composed of acetic acid ester of cellulose, propionic acid ester, butyric acid ester, mixed ester thereof and the like can be mentioned. Among them, triacetyl cellulose, diacetyl cellulose, cellulose acetate propionate, cellulose acetate butyrate and the like are preferable.

The (meth) acrylic acid-based resin is a resin containing a compound having a (meth) acryloyl group as a main constituent monomer. Specific examples of the (meth) acrylic resin include poly (meth) acrylic acid esters such as polymethyl methacrylate; methyl methacrylate- (meth) acrylic acid copolymers; methyl methacrylate- (meth) acrylic acid esters. Copolymers: Methyl methacrylate-acrylic acid ester- (meth) acrylic acid copolymer; (meth) methyl acrylate-styrene copolymer (MS resin, etc.); methyl methacrylate-cyclohexyl methacrylate copolymer, methacryl Includes a copolymer of methyl methacrylate such as a methyl- (meth) acrylate norbornyl copolymer and a compound having an alicyclic hydrocarbon group. _{A polymer containing poly (meth) acrylic acid C 1-6} alkyl ester as a main component, such as methyl poly (meth) acrylate, is preferably used, and more preferably methyl methacrylate is used as a main component (50 to 100% by weight). , Preferably 70 to 100% by weight), a methyl methacrylate-based resin is used.

The (meth) acrylic acid-based resin may have a structural unit that expresses positive birefringence. If it has a structural unit that expresses positive birefringence and a structural unit that expresses negative birefringence, the position of the film formed from the (meth) acrylic acid-based resin can be adjusted by adjusting the abundance ratio thereof. The phase difference can be controlled, and a (meth) acrylic acid-based resin film having a low phase difference can be obtained. As the structural unit that expresses positive birefringence, for example, a structural unit constituting a lactone ring, polycarbonate, polyvinyl alcohol, cellulose acetate, polyester, polyarylate, polyimide, polyolefin, etc., is represented by the general formula (1) described later. Structural units can be mentioned. Examples of the structural unit that expresses negative birefringence include structural units derived from styrene-based monomers, maleimide-based monomers, etc., polymethylmethacrylate structural units, structural units represented by the general formula (3) described later, and the like. Can be mentioned.

As the (meth) acrylic acid-based resin, a (meth) acrylic acid-based resin having a lactone ring structure or a glutarimide structure is preferably used. A (meth) acrylic acid-based resin having a lactone ring structure or a glutarimide structure has excellent heat resistance. More preferably, it is a (meth) acrylic acid-based resin having a glutarimide structure. By using a (meth) acrylic acid-based resin having a glutarimide structure, a (meth) acrylic acid-based resin film having low moisture permeability and low phase difference and ultraviolet transmittance can be obtained. Examples of the (meth) acrylic acid-based resin having a glutarimide structure (hereinafter, also referred to as “glutarimide resin”) include JP-A-2006-309033, JP-A-2006-317560, and JP-A-2006-328329. , JP-A-2006-328334, JP-A-2006-337491, JP-A-2006-337492, JP-A-2006-337493, JP-A-2006-337569, JP-A-2007-9182, It is described in Kai 2009-161744. These statements are incorporated herein by reference.

The glutarimide resin is preferably a structural unit represented by the following general formula (1) (hereinafter, also referred to as “glutarimide unit”) and a structural unit represented by the following general formula (2) (hereinafter, “( Meta) Also referred to as "acrylic acid ester unit").

[In the general formula (1), R ¹ and R ² are each independently hydrogen or an alkyl group having 1 to 8 carbon atoms, and R ³ is hydrogen, an alkyl group having 1 to 18 carbon atoms, and an alkyl group having 1 to 18 carbon atoms. It is a substituent containing 3 to 12 cycloalkyl groups or an aromatic ring having 5 to 15 carbon atoms.
In the general formula (2), R ⁴ and R ⁵ are each independently hydrogen or an alkyl group having 1 to 8 carbon atoms, and R ⁶ is hydrogen, an alkyl group having 1 to 18 carbon atoms, and 3 carbon atoms. It is a cycloalkyl group of ~ 12 or a substituent containing an aromatic ring having 5 to 15 carbon atoms. ]

The glutarimide resin may further contain a structural unit represented by the following general formula (3) (hereinafter, also referred to as “aromatic vinyl unit”), if necessary.

[In the general formula (3), R ⁷ is hydrogen or an alkyl group having 1 to 8 carbon atoms, and R ⁸ is an aryl group having 6 to 10 carbon atoms].

In the above general formula (1), preferably, R ¹ and R ² are independently hydrogen or methyl groups, and R ³ is hydrogen, methyl group, butyl group, or cyclohexyl group, and more preferably. , R ¹ is a methyl group, R ² is a hydrogen, and R ³ is a methyl group.

The glutarimide resin is a glutarimide unit, may include only a single type, R ¹ in the general formula ^(1), R ^2, and R ³ also include a plurality of different types good.

The glutarimide unit can be formed by imidizing the (meth) acrylic acid ester unit represented by the above general formula (2). The glutarimide unit is an acid anhydride such as maleic anhydride, or a half ester of such an acid anhydride and a linear or branched alcohol having 1 to 20 carbon atoms; crotonic acid, methacrylic acid, maleic acid. It can also be formed by imidizing α, β-ethylenically unsaturated carboxylic acids such as maleic anhydride, itaconic acid, itaconic anhydride, crotonic acid, fumaric acid, and citraconic acid.

In the above general formula (2), preferably R ⁴ and R ⁵ are independently hydrogen or methyl groups, R ⁶ is hydrogen or methyl group, and more preferably R ⁴ is hydrogen. , R ⁵ is a methyl group and R ⁶ is a methyl group.

Glutarimide resin as (meth) acrylic acid ester unit, may include only a single type, include R ^4, R ^5, and a plurality of types of R ⁶ are different in the above general formula (2) You may be.

The glutarimide resin preferably contains styrene, α-methylstyrene and the like, and more preferably styrene, as the aromatic vinyl unit represented by the above general formula (3). By using a glutarimide resin having such an aromatic vinyl unit, the positive birefringence of the glutarimide structure can be reduced, and a (meth) acrylic resin film having a lower phase difference can be obtained.

The glutarimide resin may contain only a single type as the aromatic vinyl unit, or may contain a plurality of types in which ^{R 7} and R ^{8 in the above general formula (3) are different.}

The content of the glutarimide unit in glutarimide resin is preferably, for example, vary depending on the structure and the like of R ^3. The content of the glutarimide unit is preferably 1% by weight to 80% by weight, more preferably 1% by weight to 70% by weight, still more preferably 1% by weight, based on the total structural unit of the glutarimide resin. It is about 60% by weight, and particularly preferably 1% by weight to 50% by weight. When the content of the glutarimide unit is in such a range, a low phase difference (meth) acrylic resin film having excellent heat resistance can be obtained.

The content of the aromatic vinyl unit in the glutarimide resin can be appropriately set according to the purpose and required properties. Depending on the application, the content of the aromatic vinyl unit may be zero. When the aromatic vinyl unit is contained, the content thereof is preferably 10% by weight to 80% by weight, more preferably 20% by weight to 80% by weight, based on the glutarimide unit of the glutarimide resin. It is more preferably 20% by weight to 60% by weight, and particularly preferably 20% by weight to 50% by weight. When the content of the aromatic vinyl unit is in such a range, a (meth) acrylic acid-based resin film having a low phase difference and excellent heat resistance and mechanical strength can be obtained.

If necessary, the glutarimide resin may be further copolymerized with other structural units other than the glutarimide unit, the (meth) acrylic acid ester unit, and the aromatic vinyl unit. Other structural units include, for example, a structure composed of nitrile-based monomers such as acrylonitrile and methacrylonitrile; maleimide-based monomers such as maleimide, N-methylmaleimide, N-phenylmaleimide, and N-cyclohexylmaleimide. The unit is mentioned. These other structural units may be directly copolymerized or graft-copolymerized in the glutarimide resin.

The olefin-based resin is composed of a structural unit derived from a chain aliphatic olefin such as ethylene and propylene, or an alicyclic olefin such as norbornene or a substitute thereof (hereinafter, these are collectively referred to as a norbornene-based monomer). It is a resin. The olefin resin may be a copolymer using two or more kinds of monomers.

As the olefin resin, a cyclic olefin resin which is a resin mainly containing a constituent unit derived from an alicyclic olefin is preferably used. Typical examples of the alicyclic olefin constituting the cyclic olefin resin include norbornene-based monomers. Norbornene is a compound in which one carbon-carbon bond of norbornane is a double bond, and is named bicyclo [2,2,1] hept-2-ene according to the IUPAC nomenclature. be. Examples of the substitution product of norbornene include 3-substituted product, 4-substituted product, 4,5-di-substituted product, etc., with the double bond position of norbornene at the 1,2-position, and further. Dicyclopentadiene, dimethanooctahydronaphthalene and the like can also be mentioned.

The cyclic olefin resin may or may not have a norbornane ring as its constituent unit. Examples of the norbornene-based monomer forming a cyclic olefin-based resin having no norbornene ring as a constituent unit include those having a 5-membered ring by ring-opening, typically norbornene, dicyclopentadiene, 1- or 4-. Examples thereof include methylnorbornene and 4-phenylnorbornene. When the cyclic olefin-based resin is a copolymer, the arrangement state of the molecule is not particularly limited, and it may be a random copolymer, a block copolymer, or a graft. It may be a polymer.

More specific examples of the cyclic olefin resin include, for example, a ring-opening polymer of a norbornene-based monomer, a ring-opening copolymer of a norbornene-based monomer and another monomer, and addition of maleic acid and cyclopentadiene to them. Examples thereof include polymer modified products made, and polymers or copolymers obtained by hydrogenating them; addition polymers of norbornene-based monomers, and addition copolymers of norbornene-based monomers and other monomers. Examples of other monomers used as copolymers include α-olefins, cycloalkenes, non-conjugated dienes and the like. Further, the cyclic olefin resin may be a copolymer using one or more of norbornene-based monomers and other alicyclic olefins.

As the cyclic olefin resin, a ring-opening polymer using a norbornene-based monomer or a resin obtained by hydrogenating a ring-opening copolymer is preferably used.

The resin material constituting the above-mentioned resin film may contain an appropriate additive as long as the transparency is not impaired. Additives include, for example, antioxidants, UV absorbers, antistatic agents, lubricants, nucleating agents, antifogging agents, antiblocking agents, phase difference reducing agents, stabilizers, processing aids, plasticizers, impact resistant aids. , Matters, antibacterial agents, antifungal agents and the like. A plurality of kinds of these additives may be used in combination.

As a method for forming a resin film using the above-mentioned resin material, any optimum method may be appropriately selected. For example, a solvent casting method in which a resin dissolved in a solvent is cast on a metal band or drum and the solvent is dried and removed to obtain a film. The resin is heated above its melting temperature, kneaded and extruded from a die. , A melt extrusion method for obtaining a film by cooling, and the like. In the melt extrusion method, a single-layer film can be extruded, or a multilayer film can be extruded at the same time.

As described above, the resin film may be a stretched film that has been stretched.
The tensile elastic modulus may be adjusted to a desired range by performing a stretching process. Examples of the stretching treatment include uniaxial stretching and biaxial stretching.

<Display device>
The optical laminate of the present invention can be attached to the visible side of the image display element via the first pressure-sensitive adhesive layer 15 to form a display device. Examples of the image display element include a liquid crystal display element, an organic EL display element, and the like.

Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples. In the examples, the part and% indicating the content or the amount used are based on weight unless otherwise specified. The physical properties in the following examples are measured by the following methods.

[Measuring method]
(1) Method for measuring film thickness Measure using MH-15M, a digital micrometer manufactured by Nikon Corporation.

(2) Method for measuring phase difference value Measurement is performed using a phase difference measuring device KOBRA-WPR (manufactured by Oji Measuring Instruments Co., Ltd.).

(3) Method for measuring storage elastic modulus:
The storage elastic modulus (G') of the pressure-sensitive adhesive layer is measured according to the following (I) to (III).
(I) Two samples of 25 ± 1 mg are taken out from the pressure-sensitive adhesive layer, and each sample is formed into a substantially ball shape.
(II) The two samples obtained in (I) above are attached to the upper and lower surfaces of the I-type jig, and both the upper and lower surfaces are sandwiched between the L-type jigs. The composition of the measurement sample is an L-type jig / adhesive / I-type jig / adhesive / L-type jig.
(III) The storage elastic modulus (G') of the sample thus prepared was measured at a temperature of 23 ° C., a frequency of 1 Hz, and an initial stage using a dynamic viscoelasticity measuring device [DVA-220, manufactured by IT Measurement Control Co., Ltd.]. Measure under the condition of strain 1N.

(A) Fabrication of Polarizer (Preparation of Polarizer 1)
A 75 μm-thick polyvinyl alcohol film made of polyvinyl alcohol having an average degree of polymerization of about 2,400 and a saponification degree of 99.9 mol% or more was uniaxially stretched about 5 times by a dry method, and further maintained in a tense state. After immersing in pure water at 60 ° C. for 1 minute, it is immersed in an aqueous solution having a weight ratio of iodine / potassium iodide / water of 0.05 / 5/100 at 28 ° C. for 60 seconds. Then, it is immersed in an aqueous solution having a weight ratio of potassium iodide / boric acid / water of 8.5 / 8.5 / 100 at 72 ° C. for 300 seconds. Subsequently, the mixture was washed with pure water at 26 ° C. for 20 seconds and then dried at 65 ° C. to obtain a polarizer 1 having a thickness of 28 μm in which iodine was adsorbed and oriented on polyvinyl alcohol.

(Preparation of Polarizer 2)
A 50 μm-thick polyvinyl alcohol film made of polyvinyl alcohol having an average degree of polymerization of about 2,400 and a saponification degree of 99.9 mol% or more was uniaxially stretched about 5 times by a dry method, and further maintained in a tense state. After immersing in pure water at 60 ° C. for 1 minute, it is immersed in an aqueous solution having a weight ratio of iodine / potassium iodide / water of 0.05 / 5/100 at 28 ° C. for 60 seconds. Then, it is immersed in an aqueous solution having a weight ratio of potassium iodide / boric acid / water of 8.5 / 8.5 / 100 at 72 ° C. for 300 seconds. Subsequently, the mixture was washed with pure water at 26 ° C. for 20 seconds and then dried at 65 ° C. to obtain a polarizer 2 having a thickness of 18 μm in which iodine was adsorbed and oriented on polyvinyl alcohol.

(B) Preparation of Adhesive 50 g of a modified PVA resin containing an acetoacetyl group (manufactured by Mitsubishi Chemical Corporation: Gosenex Z-410) is dissolved in 950 g of pure water, heated at 90 ° C. for 2 hours, and then brought to room temperature. Cool to obtain PVA solution A.
Next, the PVA solution A, maleic acid, glyoxal, and pure water are blended so that each compound has the following concentration to prepare a PVA-based adhesive.
PVA concentration 3.0% by weight
Maleic acid 0.01% by weight
Glyoxal 0.15% by weight

(C) Fabrication of polarizing plate (fabrication of polarizing plate 1)
A 40 μm-thick film (KC4UY, manufactured by Konica Minolta Opto Co., Ltd.) made of triacetyl cellulose subjected to saponification treatment on one surface of the previously obtained polarizing element 1 is applied to a nip roll via the above adhesive. Was pasted together. The polarizing plate 1 is obtained by drying at 38 ° C. for 5 minutes while maintaining the tension of the laminate at 320 N / m.

(Preparation of polarizing plate 2)
The polarizing plate 2 is obtained in the same manner as the polarizing plate 1 except that the polarizing element 1 is replaced with the polarizing element 2 with respect to the polarizing element plate 1.

(Preparation of polarizing plate 3)
A film after curing using Table 1 and the cured composition 6 in paragraph [089] according to the examples of International Publication 2015/0533359 on the polarizer of the polarizing plate 1 (the surface on which the protective film is not laminated). An overcoat layer having a thickness of 1 μm (referred to as “OC” in Table 1) is laminated to obtain a polarizing plate 3.

(Preparation of polarizing plate 4)
The composition of the cured composition BLC-9 described in paragraph [0091] according to the polarizing plate 15 in the examples of JP-A-2017-075986 on the polarizer of the polarizing plate 1 (the surface on which the protective film is not laminated). An overcoat layer having a thickness of 2.5 μm after curing (referred to as “aqueous dispersion OC” in Table 1) is laminated with a material to obtain a polarizing plate 4.

(Preparation of polarizing plate 5)
A 40 μm-thick film (KC4UY, manufactured by Konica Minolta Opto Co., Ltd.) made of triacetyl cellulose that has been subjected to a saponification treatment is applied to one surface of the previously obtained polarizing element 1 and ken is applied to the other surface. A 20 μm-thick film made of triacetyl cellulose that has been subjected to a chemical treatment [trade name “ZRG20SL” manufactured by Fujifilm Co., Ltd., referred to as “Z-TAC” in Table 1] (in-plane retardation value Re at a wavelength of 550 nm). 1.1 nm, the retardation value Rth in the thickness direction is 1.3 nm), respectively, are bonded via the above-mentioned adhesive, and dried at 60 ° C. for 5 minutes to obtain a polarizing plate 5.

(D) Preparation of high retardation film A Cosmoshine SRF (Super Reduction Film) (thickness 80 μm) manufactured by Toyobo Co., Ltd. was used. The in-plane retardation value Re [550] is 8400 nm.

(E) Preparation of Adhesive Layer Adhesive Layer A: Commercially available sheet-shaped acrylic adhesive layer having a thickness of 15 μm (storage elastic modulus 0.06 MPa)
Adhesive layer B: Commercially available sheet-like acrylic adhesive layer with a thickness of 25 μm (storage elastic modulus 0.06 MPa)

[Example 1]
The pressure-sensitive adhesive layer A is bonded to one side of the high retardation film. When these materials are bonded together, a corona treatment is performed on the bonded surfaces of the materials.

The KC4UY surface of the polarizing plate 1 produced above and the pressure-sensitive adhesive layer surface of the high retardation film are laminated so that the angle θ formed by the absorption axis of the polarizer and the slow axis of the high retardation film is 45 °. Body A is made. When these materials are bonded together, a corona treatment is performed on the bonded surfaces of the materials.

Finally, the adhesive layer B is bonded to the surface of the obtained optical laminate A opposite to the KC4UY surface. When these materials are bonded together, a corona treatment is performed on the bonded surfaces of the materials.

[Examples 2 to 4 and Comparative Example 1]
As shown in Table 1, the pressure-sensitive adhesive layer B is bonded to the optical laminate A of Example 1 in the same manner as in Example 1 except that the polarizing plate 1 is replaced with the polarizing plates 2 to 5. The optical laminates B to E (Examples 2 to 4 and Comparative Example 1) are produced.

(Preparation of sample A for evaluation)
The optical laminate A is cut into a size of 20 mm × 20 mm as an optical laminate on the visual side, and bonded to a non-alkali glass having a thickness of 0.7 mm and a size of 30 mm × 30 mm via an adhesive layer B. do. The optical laminate F is produced in the same manner as above except that the high retardation film and the pressure-sensitive adhesive layer A are not laminated on the optical laminate E of Comparative Example 1. The optical laminate F (without high retardation film bonding) is cut into a size of 20 mm × 20 mm, and the optical laminate A of the non-alkali glass of the above sample is cut into a size of 20 mm × 20 mm, and the optical laminate A on the back side is used as the optical laminate. , The optical laminate F is bonded via the pressure-sensitive adhesive layer B so that the absorption axes of the polarizers are cross-nicols, and an evaluation sample A is prepared.

(Preparation of evaluation samples B to E)
For the evaluation sample A, the evaluation samples B to E are produced in the same manner except that the optical laminate A, which is the optical laminate on the visual side, is replaced with the optical laminates B to E, respectively.

(Evaluation of change in black brightness)
The side to which the optical laminate F, which is the optical laminate on the back side of the evaluation samples A to E prepared above, is bonded is placed on the irradiation surface of the white backlight module ^{having a brightness of 20000 cd / m 2, and the evaluation sample side (} After measuring the brightness from the high retardation film) side (black brightness 1), store it in a heating environment at a temperature of 95 ° C. for 240 hours, cool it to room temperature, and then measure the brightness again (black brightness 2). The rate of change (%) of 2 is calculated and used as the black luminance change. In particular,
Black brightness change (%) = {| Black brightness 2-Black brightness 1 | / Black brightness 1} x 100
To obtain the change in black luminance. The evaluation results are shown in Table 1.

From the results shown in Table 1, the black brightness of the optical laminate with the high retardation film bonded at 45 ° may increase after the high temperature durability test, but the optical laminate on the visual side is on the display element side of the polarizer. It can be seen that the configuration without the resin film can suppress the increase in black brightness after the high temperature durability test.

1 polarizing plate, 10 polarizing elements, 11 resin layers, 12 protective films, 13 high retardation films, 14 second adhesive layers, 15 first adhesive layers, 100, 200 optical laminates.

Claims

A high retardation film, a polarizer, and an adhesive layer are provided in this order.
The pressure-sensitive adhesive layer is provided so as to be in contact with the surface of the polarizer.
The in-plane retardation value of the high retardation film is 3000 nm to 30,000 nm.
An optical laminate in which the angle formed by the slow axis of the high retardation film and the absorption axis of the polarizer is 40 ° to 50 °.
A high retardation film, a polarizer, a resin layer containing a cured resin product, and an adhesive layer are provided in this order.
The resin layer is provided so as to be in contact with the polarizer and the pressure-sensitive adhesive layer.
The in-plane retardation value of the high retardation film is 3000 nm to 30,000 nm.
An optical laminate in which the angle formed by the slow axis of the high retardation film and the absorption axis of the polarizer is 40 ° to 50 °.
The optical laminate according to claim 2, wherein the resin layer is an overcoat layer.
The optical laminate according to any one of claims 1 to 3, further comprising a protective film provided between the high retardation film and the polarizer.
The optical laminate according to any one of claims 1 to 4, wherein the polarizing element has a thickness of 30 μm or less.
The optical laminate according to any one of claims 1 to 5, wherein the thickness of the high retardation film is 200 μm or less.
The image display element and the optical laminate according to any one of claims 1 to 6 are provided.
A display device in which the pressure-sensitive adhesive layer of the optical laminate is bonded to the surface of the image display element.