WO2020066831A1

WO2020066831A1 - Polarizing plate composite and image display device

Info

Publication number: WO2020066831A1
Application number: PCT/JP2019/036742
Authority: WO
Inventors: 政大藤田
Original assignee: 住友化学株式会社
Priority date: 2018-09-28
Filing date: 2019-09-19
Publication date: 2020-04-02
Also published as: TWI828762B; JP2020052365A; CN112771421A; KR20210064282A; TW202036046A

Abstract

A polarizing plate composite comprising, in order: a linear polarizing plate; a 1/2 wavelength layer; a first adhesive layer comprising an active energy ray curable adhesive that has been cured; and a 1/4 wavelength layer. The angle formed between the fast axis of the 1/2 wavelength layer and the transmission axis of the linear polarizing plate is 10–20°. The absolute value for the difference between the refractive index of the first adhesive layer at a wavelength of 589 nm and the refractive index in the fast axis direction of the 1/2 wavelength layer at a wavelength of 589 nm is less than 0.05.

Description

Polarizing plate composite and image display device

The present invention relates to a polarizing plate composite and an image display device having the polarizing plate composite.

Conventionally, in an image display device, a method has been adopted in which an optical laminate having antireflection performance is arranged on the viewing side of an image display panel to suppress a decrease in visibility due to reflection of extraneous light.

円 As an optical laminate having antireflection performance, a circularly polarizing plate composed of a linear polarizing plate and a retardation layer is known. In the circularly polarizing plate, extraneous light directed to the image display panel is converted into linearly polarized light by a linearly polarizing plate, and then converted into circularly polarized light by a phase difference layer. The external light converted to circularly polarized light is reflected on the surface of the image display panel, but the direction of rotation of the polarization plane is reversed at the time of this reflection, and is converted to linearly polarized light by the retardation layer. Light is shielded by the plate. As a result, emission to the outside is significantly suppressed.

Japanese Patent Application Laid-Open No. 2018-17996 (Patent Document 1) discloses that, in a polarizing plate with a retardation layer having a plurality of retardation layers, the difference in average refractive index between the plurality of retardation layers is adjusted so that reflected light can be reduced. It is described that unevenness can be suppressed and visibility can be improved.

JP 2018-17996 A

The object of the present invention is to provide a novel polarizing plate composite in which the occurrence of interference unevenness is suppressed, and an image display device including the composite polarizing plate.

The present invention provides a polarizing plate composite and an image display device described below.
[1] A linear polarizing plate, a 波長 wavelength layer, a first adhesive layer obtained by curing an active energy ray-curable adhesive, and a 波長 wavelength layer are provided in this order,
The angle between the fast axis of the １／ wavelength layer and the transmission axis of the linear polarizer is 10 ° or more and 20 ° or less,
The polarizing plate composite, wherein the absolute value of the difference between the refractive index of the first adhesive layer at a wavelength of 589 nm and the refractive index of the 波長 wavelength layer in the fast axis direction at a wavelength of 589 nm is less than 0.05. .
[2] The polarizing plate composite according to [1], wherein the first adhesive layer has a refractive index at a wavelength of 589 nm of less than 1.55.
[3] The quarter wavelength layer has an in-plane average refractive index, which is an average value of a refractive index in a fast axis direction and a refractive index in a slow axis direction at a wavelength of 589 nm, of less than 1.58. ] Or the polarizing plate composite according to [2].
[4] In-plane which is the average value of the refractive index of the first adhesive layer at a wavelength of 589 nm and the refractive index of the １／ wavelength layer at a wavelength of 589 nm in the fast axis direction and the slow axis direction. The polarizing plate composite according to any one of [1] to [3], wherein the absolute value of the difference from the average refractive index is less than 0.05.
[5] The polarizing plate composite according to any one of [1] to [4], which is a circular polarizing plate.
[6] The polarizing plate composite according to any one of [1] to [5], wherein the 波長 wavelength layer includes a retardation developing layer that is a liquid crystal layer.
[7] The polarizing plate composite according to any one of [1] to [6], wherein the 波長 wavelength layer includes a retardation developing layer that is a liquid crystal layer.
[8] The polarizing plate composite according to any one of [1] to [7], wherein the first adhesive layer has a thickness of 5 μm or less.
[9] An image display device comprising: an image display panel; and the polarizing plate composite according to any one of [1] to [8] disposed on the viewing side of the image display panel.
[10] The image display device according to [9], wherein the polarizing plate composite is arranged in a direction in which the linear polarizing plate is located on a viewing side.
[11] The image display device according to [9] or [10], which is an organic electroluminescence display device.

According to the polarizing plate composite of the present invention, interference unevenness can be suppressed.

FIG. 1 is a schematic cross-sectional view schematically showing one example of a polarizing plate composite of the present invention. FIG. 3 is a schematic cross-sectional view schematically illustrating an example of a retardation layer including a liquid crystal layer as a retardation expression layer. (A) to (D) are schematic cross-sectional views schematically showing an example of each production step in the method for producing a polarizing plate composite of the present invention. (A), (B) is schematic sectional drawing which shows typically another example of each manufacturing process in the manufacturing method of the polarizing plate composite of this invention.

Hereinafter, the polarizing plate composite and the image display device of the present invention will be described with reference to the drawings.

[Composite retarder]
FIG. 1 is a schematic cross-sectional view schematically showing one example of the polarizing plate composite of the present invention. As shown in FIG. 1, the polarizing plate composite 10 has a linear polarizing plate 13, a second adhesive layer 22, a 波長 wavelength layer 11, a first adhesive layer 21, and a 波長 wavelength layer 12 sequentially laminated. . In the polarizing plate composite 10, the angle between the fast axis of the half-wavelength layer 11 and the transmission axis of the linear polarizing plate 13 is 10 ° or more and 20 ° or less, preferably 12 ° or more and 18 ° or less, More preferably, it is about 15 °. In the polarizing plate composite 10, the angle between the fast axis of the quarter wavelength layer 12 and the transmission axis of the linear polarizing plate 13 is preferably 70 ° or more and 80 ° or less, more preferably 72 ° or more and 78 ° or less. And more preferably about 75 °. In the polarizing plate composite 10, the angle between the slow axis of the １／ wavelength layer 11 and the slow axis of the 波長 wavelength layer 12 is preferably 55 ° or more and 65 ° or less, more preferably 57 ° or less. It is not less than 63 ° and not more than 63 °, more preferably about 60 °. By being laminated so as to form such an angle, the polarizing plate composite 10 can be suitably used as a circularly polarizing plate.

Even with a relationship of an angle other than the above angle, a polarizing plate composite that can be suitably used as a circular polarizing plate can be formed, but by satisfying the above relationship, the wavelength of the first adhesive layer at 589 nm is satisfied. Even when the refractive index is less than 1.55, the interference unevenness can be effectively suppressed.

The thickness of the polarizing plate composite 10 is preferably 30 μm to 50 μm, more preferably 30 μm to 200 μm, and still more preferably 30 μm to 150 μm, from the viewpoint of thinning.

について The refractive index of the first adhesive layer 21 at a wavelength of 589 nm is referred to as “refractive index n21”. The first adhesive layer 21 has no phase difference and can be regarded as having the same value regardless of the refractive index in any direction. Therefore, the “refractive index n21” may be a refractive index in any direction.

Regarding the １／ wavelength layer 11, the refractive index at the wavelength of 589 nm in the slow axis direction is “refractive index n11 _x ”, the refractive index in the fast axis direction is “refractive index n11 _y ”, and the refractive index in the thickness direction is “refraction”. Ratio n11 _z , the average value of n11 _x and n11 _y is “in-plane average refractive index n11 _{x, y} ”, and the average value of n11 _x , n11 _y, and n11 _z is “three-dimensional average refractive index n11 _{x, y”. , Z} ”. The in-plane average refractive index n11 _{x, y} and the three-dimensional average refractive index n11 _{x, y, z} are values calculated by the following equations (1) and (2), respectively.
n11 _{x, y} = (n11 _x + n11 _y ) / 2 (1)
_{_{_{n11 x, y, z = (}}} n11 x + n11 y + n11 z) / 3 (2)

Regarding the 層 wavelength layer 12, the refractive index at the wavelength of 589 nm in the slow axis direction is “refractive index n12 _x ”, the refractive index in the fast axis direction is “refractive index n12 _y ”, and the refractive index in the thickness direction is “refraction”. Ratio n12 _z ”, the average value of n12 _x and n12 _y is“ in-plane average refractive index n12 _{x, y} ”, and the average value of n12 _x , n12 _y and n12 _z is“ three-dimensional average refractive index n12 _{x, y ”. , Z} ”. The in-plane average refractive index n12 _{x, y} and the three-dimensional average refractive index n12 _{x, y, z} are values calculated by the following equations (3) and (4), respectively.
n12 _{x, y} = (n12 _x + n12 _y ) / 2 (3)
n12 _{x, y, z} = (n12 _x + n12 _y + n12 _z ) / 3 (4)

<First adhesive layer>
The first adhesive layer 21 is formed by curing an active energy ray-curable adhesive. The thickness of the first adhesive layer 21 is preferably from 0.1 μm to 50 μm, and more preferably from 0.1 μm to 5 μm.

The refractive index n21 of the wavelength 589nm of the first adhesive layer 21, the absolute value calculated by 1/2 which is the difference between the refractive index n11 _y of the fast axis direction at a wavelength 589nm wavelength layer 11 (5) X1:
X1 = | n11 _y -n21 | (5)
Is less than 0.05, preferably 0.04 or less. When the first adhesive layer 21 and the half-wavelength layer 11 satisfy the above relationship with respect to the refractive index, interference unevenness can be suppressed. In order for the first adhesive layer 21 and the half-wavelength layer 11 to satisfy the above-mentioned relationship with respect to the refractive index, for example, the composition of the active energy ray-curable adhesive used for forming the first adhesive layer 21 is adjusted. Or by adjusting the liquid crystal material used to form the half-wavelength layer 11.

Absolute value calculated by equation (6), which is the difference between the refractive index n21 of the first adhesive layer 21 at a wavelength of 589 nm and the in-plane average refractive index n12 _{x, y} of the quarter wavelength layer 12 at a wavelength of 589 nm. X2:
X2 = | n12 _{x, y} -n21 | (6)
Is preferably less than 0.05, more preferably 0.04 or less. When the first adhesive layer 21 and the 波長 wavelength layer 12 satisfy the above-mentioned relationship in refractive index, interference unevenness can be suppressed. In order for the first adhesive layer 21 and the 波長 wavelength layer 12 to satisfy the above-mentioned relationship with respect to the refractive index, for example, the composition of the active energy ray-curable adhesive used for forming the first adhesive layer 21 is adjusted. Or by adjusting the liquid crystal material used to form the quarter wavelength layer 11.

The first adhesive layer 21 has a refractive index n21 at a wavelength of 589 nm, for example, less than 1.55.
In the present invention, even when the refractive index n21 of the first adhesive layer 21 is as small as less than 1.55, interference unevenness can be suppressed.

Active energy ray-curable adhesives are those that cure when irradiated with active energy rays. For example, a cationically polymerizable active energy ray-curable adhesive containing an epoxy compound and a cationic polymerization initiator, a radically polymerizable active energy ray-curable adhesive containing an acrylic curing component and a radical polymerization initiator, an epoxy compound An active energy ray-curable adhesive containing both a cationically polymerizable curing component and a radically polymerizable curing component such as an acrylic compound, in which a cationic polymerization initiator and a radical polymerization initiator are blended. And an electron beam-curable adhesive cured by irradiating an active energy ray-curable adhesive containing no initiator with an electron beam. Since radical polymerization tends to cause large curing shrinkage, a cationically polymerizable active energy ray-curable adhesive containing an epoxy compound and a cationic polymerization initiator is preferable.

Select a cationically polymerizable epoxy compound that is itself liquid at room temperature, has appropriate fluidity even without the presence of a solvent, and gives an appropriate cured adhesive strength. The active energy ray-curable adhesive containing the polymerization initiator can eliminate the drying equipment which is usually required in the step of bonding the 波長 wavelength layer and the 波長 wavelength layer. Further, by irradiating an appropriate active energy dose, the curing speed can be accelerated, and the production speed can be improved.

Epoxy compounds used in such adhesives include, for example, glycidyl ethers of aromatic compounds or chain compounds having a hydroxyl group, glycidyl aminations of compounds having an amino group, and chain compounds having a CC double bond. Glycidyloxy group or epoxyethyl group bonded directly or via alkylene to a saturated carbocycle, or an alicyclic epoxy compound having an epoxy group bonded directly to a saturated carbocycle. it can. Each of these epoxy compounds may be used alone, or a plurality of different types may be used in combination. Of these, alicyclic epoxy compounds are preferably used because of their excellent cationic polymerizability.

The glycidyl etherified product of an aromatic compound or a chain compound having a hydroxyl group can be produced, for example, by a method in which epichlorohydrin is addition-condensed to the hydroxyl group of the aromatic compound or the chain compound under basic conditions. Such a glycidyl etherified product of an aromatic compound or a chain compound having a hydroxyl group includes diglycidyl ether of bisphenols, polyaromatic ring type epoxy resin, diglycidyl ether of alkylene glycol or polyalkylene glycol, and the like. .

Examples of the diglycidyl ether of bisphenols include glycidyl ether of bisphenol A and its oligomer, glycidyl ether of bisphenol F and its oligomer, 3,3 ', 5,5'-tetramethyl-4,4'- Glycidyl ether products of biphenol and oligomers thereof are exemplified.

As the polyaromatic ring type epoxy resin, for example, glycidyl etherified phenol novolak resin, glycidyl etherified cresol novolak resin, glycidyl etherified phenol aralkyl resin, glycidyl etherified naphthol aralkyl resin, glycidyl ether phenol dicyclopentadiene resin And the like. Furthermore, glycidyl etherified trisphenols and oligomers thereof also belong to the polyaromatic ring type epoxy resin.

Examples of the diglycidyl ether of alkylene glycol or polyalkylene glycol include glycidyl ether of ethylene glycol, glycidyl ether of diethylene glycol, glycidyl ether of 1,4-butanediol, and glycidyl ether of 1,6-hexanediol. No.

A glycidyl aminated compound of a compound having an amino group can be produced, for example, by a method of adding and condensing epichlorohydrin to the amino group of the compound under basic conditions. The compound having an amino group may have a hydroxyl group at the same time. Such glycidyl aminated compounds having an amino group include glycidyl aminated 1,3-phenylenediamine and oligomers thereof, glycidyl aminated 1,4-phenylenediamine and oligomers thereof, 3-aminophenol Glycidyl aminated and glycidyl etherified products and oligomers thereof, and glycidyl aminated and glycidyl etherified products of 4-aminophenol and oligomers thereof.

The epoxidized product of a chain compound having a CC double bond can be produced by a method of epoxidizing the CC double bond of the chain compound with a peroxide under basic conditions. The chain compound having a CC double bond includes butadiene, polybutadiene, isoprene, pentadiene, hexadiene and the like. Terpenes having a double bond can also be used as an epoxidation raw material, and examples of acyclic monoterpenes include linalool. The peroxide used for epoxidation can be, for example, hydrogen peroxide, peracetic acid, tert-butyl hydroperoxide, and the like.

An alicyclic epoxy compound in which a glycidyloxy group or an epoxyethyl group is bonded to a saturated carbon ring directly or via an alkylene is an aromatic ring of an aromatic compound having a hydroxyl group represented by the aforementioned bisphenols. Examples include glycidyl ether of a hydrogenated polyhydroxy compound obtained by hydrogenation, glycidyl ether of a cycloalkane compound having a hydroxyl group, and epoxidized compound of a cycloalkane compound having a vinyl group.

The epoxy compounds described above can be easily obtained as commercial products. For example, "jER" series sold by Mitsubishi Chemical Corporation and DIC Corporation are sold under trade names. "Epiclon", "Epototo (registered trademark)" sold by Toto Kasei Co., Ltd., "ADEKARESIN (registered trademark)" sold by ADEKA CORPORATION, sold by Nagase ChemteX Corporation Examples include "Denacol (registered trademark)", "Dow Epoxy" sold by Dow Chemical Company, and "Tepic (registered trademark)" sold by Nissan Chemical Industries, Ltd.

On the other hand, an alicyclic epoxy compound in which an epoxy group is directly bonded to a saturated carbocyclic ring is, for example, a compound in which a CC double bond of a non-aromatic cyclic compound having a CC double bond in the ring is substituted with a basic compound. It can be produced by a method of epoxidation using a peroxide under conditions. As the non-aromatic cyclic compound having a CC double bond in the ring, for example, a compound having a cyclopentene ring, a compound having a cyclohexene ring, a cyclopentene ring or a cyclohexene ring having at least two more carbon atoms bonded thereto And polycyclic compounds forming an additional ring. The non-aromatic cyclic compound having a CC double bond in the ring may have another CC double bond outside the ring. Examples of the non-aromatic cyclic compound having a CC double bond in the ring include cyclohexene, 4-vinylcyclohexene, and the monocyclic monoterpenes limonene and α-pinene.

The alicyclic epoxy compound in which an epoxy group is directly bonded to a saturated carbocyclic ring has an alicyclic structure having an epoxy group directly bonded to a ring as described above, and is bonded to a molecule via an appropriate linking group. At least two compounds may be formed. The linking group here includes, for example, an ester bond, an ether bond, an alkylene bond and the like.

Specific examples of the alicyclic epoxy compound in which an epoxy group is directly bonded to a saturated carbon ring include the following.
3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexanecarboxylate,
1,2-epoxy-4-vinylcyclohexane,
1,2-epoxy-4-epoxyethylcyclohexane,
1,2-epoxy-1-methyl-4- (1-methylepoxyethyl) cyclohexane, 3,4-epoxycyclohexylmethyl (meth) acrylate,
An adduct of 2,2-bis (hydroxymethyl) -1-butanol with 4-epoxyethyl-1,2-epoxycyclohexane,
Ethylene bis (3,4-epoxycyclohexanecarboxylate),
Oxydiethylene bis (3,4-epoxycyclohexanecarboxylate),
1,4-cyclohexanedimethyl bis (3,4-epoxycyclohexanecarboxylate),
3- (3,4-epoxycyclohexylmethoxycarbonyl) propyl 3,4-epoxycyclohexanecarboxylate and the like.

The alicyclic epoxy compound in which an epoxy group is directly bonded to the saturated carbon ring described above can also be easily obtained as a commercial product. For example, each of the alicyclic epoxy compounds is sold under the trade name of Daicel Corporation. "Celoxide (registered trademark)" and "Cyclomer (registered trademark)", "Cyracure @ UVR" series sold by Dow Chemical Company, and the like.

硬化 The curable adhesive containing an epoxy compound may further contain an active energy ray-curable compound other than the epoxy compound. Examples of the active energy ray-curable compound other than the epoxy compound include an oxetane compound and an acrylic compound. Among them, it is preferable to use an oxetane compound in combination, since there is a possibility that the curing rate can be accelerated in the cationic polymerization.

The oxetane compound is a compound having a four-membered ring ether in the molecule, and examples thereof include the following.
1,4-bis [(3-ethyloxetane-3-yl) methoxymethyl] benzene,
3-ethyl-3- (2-ethylhexyloxymethyl) oxetane,
Bis (3-ethyl-3-oxetanylmethyl) ether,
3-ethyl-3- (phenoxymethyl) oxetane,
3-ethyl-3- (cyclohexyloxymethyl) oxetane,
Phenol novolak oxetane,
Xylylenebisoxetane,
1,3-bis [(3-ethyloxetane-3-yl) methoxy] benzene and the like.

Oxetane compounds can also be easily obtained as commercial products. For example, “Alon Oxetane (registered trademark)” series sold by Toagosei Co., Ltd., and Ube Industries, Ltd. "ETERNACOLL (registered trademark)" series and the like are available.

(4) The curable compound including the epoxy compound and the oxetane compound is preferably not diluted with an organic solvent or the like in order to make the adhesive containing these compounds solvent-free. Further, other components constituting the adhesive, even a small component including a cationic polymerization initiator and a sensitizer described below, than those dissolved in an organic solvent, the organic solvent is removed and dried. It is preferable to use a powder or liquid of the compound alone.

A cationic polymerization initiator is a compound that generates a cationic species upon irradiation with an active energy ray, for example, ultraviolet rays. Any material can be used as long as it gives the adhesive strength and curing speed required for the compounded adhesive, for example, aromatic diazonium salts; onium salts such as aromatic iodonium salts and aromatic sulfonium salts; iron-arene complexes And the like. Each of these cationic polymerization initiators may be used alone, or a plurality of different types may be used in combination.

Examples of the aromatic diazonium salt include the following.
Benzenediazonium hexafluoroantimonate,
Benzenediazonium hexafluorophosphate,
Benzenediazonium hexafluoroborate and the like.

Examples of the aromatic iodonium salt include the following.
Diphenyliodonium tetrakis (pentafluorophenyl) borate,
Diphenyliodonium hexafluorophosphate,
Diphenyliodonium hexafluoroantimonate,
Bis (4-nonylphenyl) iodonium hexafluorophosphate and the like.

Examples of the aromatic sulfonium salt include the following.
Triphenylsulfonium hexafluorophosphate,
Triphenylsulfonium hexafluoroantimonate,
Triphenylsulfonium tetrakis (pentafluorophenyl) borate,
Diphenyl (4-phenylthiophenyl) sulfonium hexafluoroantimonate,
4,4'-bis (diphenylsulfonio) diphenyl sulfide bishexafluorophosphate,
4,4'-bis [di (β-hydroxyethoxyphenyl) sulfonio] diphenyl sulfide bishexafluoroantimonate,
4,4'-bis [di (β-hydroxyethoxyphenyl) sulfonio] diphenyl sulfide 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) sulfonio-diphenylsulfide tetrakis (pentafluorophenyl) borate and the like.

Examples of the iron-arene complex include the following.
Xylene-cyclopentadienyliron (II) hexafluoroantimonate,
Cumene-cyclopentadienyliron (II) hexafluorophosphate, xylene-cyclopentadienyliron (II) tris (trifluoromethylsulfonyl) methanide and the like.

Among the cationic polymerization initiators, the aromatic sulfonium salt has an ultraviolet absorbing property even in a wavelength region of 300 nm or more, so it is excellent in curability and can provide an adhesive layer having good mechanical strength and adhesive strength. Therefore, it is preferably used.

Commercially available cationic polymerization initiators can also be easily obtained. For example, “Kayarad (registered trademark)” series sold by Nippon Kayaku Co., Ltd., and Dow Chemical Co., Ltd. "Siracure @ UVI" series sold, San-Apro Co., Ltd. photoacid generator "CPI" series, Midori Chemical Co., Ltd. photoacid generators "TAZ", "BBI" and "DTS", "ADEKA OPTOMER" series sold by ADEKA Corporation, "RHODORSIL (registered trademark)" sold by Rhodia, and the like.

In the active energy ray-curable adhesive, the cationic polymerization initiator is usually blended in a ratio of 0.5 to 20 parts by mass, preferably 1 to 15 parts by mass, based on 100 parts by mass of the active energy ray-curable adhesive. Parts by weight. If the amount is too small, curing will be insufficient, and the mechanical strength and adhesive strength of the adhesive layer may be reduced. On the other hand, if the amount is too large, the amount of ionic substances in the adhesive layer increases, so that the hygroscopicity of the adhesive layer increases, and the durability of the obtained polarizing plate may decrease.

When using an active energy ray-curable adhesive in an electron beam-curable type, it is not particularly necessary to include a photopolymerization initiator in the composition, but when using an ultraviolet-curable type, a photoradical generator is used. Is preferred. Examples of the photo radical generator include a hydrogen abstraction type photo radical generator and a cleavage type photo radical generator.

Examples of the hydrogen abstraction type photoradical generator include 1-methylnaphthalene, 2-methylnaphthalene, 1-fluoronaphthalene, 1-chloronaphthalene, 2-chloronaphthalene, 1-bromonaphthalene, 2-bromonaphthalene, and 1-iodonaphthalene. , 2-iodonaphthalene, 1-naphthol, 2-naphthol, 1-methoxynaphthalene, 2-methoxynaphthalene, naphthalene derivatives such as 1,4-dicyanonaphthalene, anthracene, 1,2-benzanthracene, 9,10-dichloroanthracene , 9,10-dibromoanthracene, 9,10-diphenylanthracene, 9-cyanoanthracene, 9,10-dicyanoanthracene, 2,6,9,10-tetracyanoanthracene and other anthracene derivatives, pyrene derivatives, carbazones , 9-methylcarbazole, 9-phenylcarbazole, 9-prop-2-ynyl-9H-carbazole, 9-propyl-9H-carbazole, 9-vinylcarbazole, 9H-carbazole-9-ethanol, 9-methyl-3- Nitro-9H-carbazole, 9-methyl-3,6-dinitro-9H-carbazole, 9-octanoylcarbazole, 9-carbazolemethanol, 9-carbazolepropionic acid, 9-carbazolepropionitrile, 9-ethyl-3, 6-dinitro-9H-carbazole, 9-ethyl-3-nitrocarbazole, 9-ethylcarbazole, 9-isopropylcarbazole, 9- (ethoxycarbonylmethyl) carbazole, 9- (morpholinomethyl) carbazole, 9-acetylcarbazole, 9 -Ant Carbazole, 9-benzyl-9H-carbazole, 9-carbazoleacetic acid, 9- (2-nitrophenyl) carbazole, 9- (4-methoxyphenyl) carbazole, 9- (1-ethoxy-2-methyl-propyl) -9H -Carbazole, 3-nitrocarbazole, 4-hydroxycarbazole, 3,6-dinitro-9H-carbazole, 3,6-diphenyl-9H-carbazole, 2-hydroxycarbazole, 3,6-diacetyl-9-ethylcarbazole and the like Carbazole derivatives, benzophenone, 4-phenylbenzophenone, 4,4'-bis (dimethoxy) benzophenone, 4,4'-bis (dimethylamino) benzophenone, 4,4'-bis (diethylamino) benzophenone, methyl 2-benzoylbenzoate Ester, 2 Benzophenone derivatives such as -methylbenzophenone, 3-methylbenzophenone, 4-methylbenzophenone, 3,3'-dimethyl-4-methoxybenzophenone, 2,4,6-trimethylbenzophenone, aromatic carbonyl compounds, [4- (4- Methylphenylthio) phenyl] -phenylmethanone, xanthone, thioxanthone, 2-chlorothioxanthone, 4-chlorothioxanthone, 2-isopropylthioxanthone, 4-isopropylthioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, And thioxanthone derivatives such as -chloro-4-propoxythioxanthone and coumarin derivatives.

The cleavage type photoradical generator is a type of photoradical generator in which the compound is cleaved by irradiation with an active energy ray to generate a radical, and specific examples thereof include arylalkyl such as benzoin ether derivatives and acetophenone derivatives. Examples include, but are not limited to, ketones, oxime ketones, acylphosphine oxides, S-phenyl thiobenzoates, titanocenes, and derivatives thereof having a high molecular weight. Commercially available cleavage type photoradical generators include 1- (4-dodecylbenzoyl) -1-hydroxy-1-methylethane, 1- (4-isopropylbenzoyl) -1-hydroxy-1-methylethane, 1-benzoyl -1-hydroxy-1-methylethane, 1- [4- (2-hydroxyethoxy) -benzoyl] -1-hydroxy-1-methylethane, 1- [4- (acryloyloxyethoxy) -benzoyl] -1-hydroxy- 1-methylethane, diphenyl ketone, phenyl-1-hydroxy-cyclohexyl ketone, benzyldimethyl ketal, bis (cyclopentadienyl) -bis (2,6-difluoro-3-pyryl-phenyl) titanium, (η6-isopropylbenzene) -(Η5-cyclopentadienyl) -iron (II) hexaf Fluorophosphate, trimethylbenzoyldiphenylphosphine oxide, bis (2,6-dimethoxy-benzoyl)-(2,4,4-trimethyl-pentyl) -phosphine oxide, bis (2,4,6-trimethylbenzoyl) -2, 4-dipentoxyphenylphosphine oxide or bis (2,4,6-trimethylbenzoyl) phenyl-phosphine oxide, (4-morpholinobenzoyl) -1-benzyl-1-dimethylaminopropane, 4- (methylthiobenzoyl) -1 -Methyl-1-morpholinoethane and the like, but are not limited thereto.

Among the active energy-curable adhesives used in the present invention, the photoradical generator contained in the electron beam-curable type, that is, each of the hydrogen abstraction type and the cleavage type photoradical generators can be used alone. In addition, a plurality of photo-radical generators may be used in combination, but more preferable in terms of stability of the photo-radical generator alone and curability are at least one combination of a cleavage type photo-radical generator. Among the cleavage-type photoradical generators, acylphosphine oxides are preferable, and more specifically, trimethylbenzoyldiphenylphosphine oxide (trade name "DAROCURE @ TPO"; Ciba Japan Co., Ltd.), bis (2,6-dimethoxy-) Benzoyl)-(2,4,4-trimethyl-pentyl) -phosphine oxide (trade name “CGI @ 403”; Ciba Japan KK) or bis (2,4,6-trimethylbenzoyl) -2,4- Dipentoxyphenyl phosphine oxide (trade name “Irgacure 819”; Ciba Japan K.K.) is preferred.

(4) The active energy ray-curable adhesive may contain a sensitizer as needed. By using a sensitizer, the reactivity is improved, and the mechanical strength and the adhesive strength of the adhesive layer can be further improved. As the sensitizer, those described above can be appropriately applied.

(4) When a sensitizer is compounded, the compounding amount is preferably in the range of 0.1 to 20 parts by mass based on 100 parts by mass of the total amount of the active energy ray-curable adhesive.

Various additives can be added to the active energy ray-curable adhesive within a range that does not impair the effect. Examples of additives that can be blended include an ion trapping agent, an antioxidant, a chain transfer agent, a tackifier, a thermoplastic resin, a filler, a flow regulator, a plasticizer, and an antifoaming agent.

These components constituting the active energy ray-curable adhesive are usually used in the state of being dissolved in a solvent. When the active energy ray-curable adhesive contains a solvent, the adhesive layer is obtained by applying the active energy ray-curable adhesive to the application surface and drying it. Components that do not dissolve in the solvent may be in a state of being dispersed in the system.

The active energy ray-curable adhesive is applied to the bonding surface of the 波長 wavelength layer 11 with the 波長 wavelength layer 12, the bonding surface of the 波長 wavelength layer 12 with the 波長 wavelength layer 11, or both. Is done. Corona treatment, plasma treatment, flame treatment, and the like are performed on the bonding surface of the １／ wavelength layer 11 with the ４ wavelength layer 12 and the bonding surface of the 波長 wavelength layer 12 with the 波長 wavelength layer 11 in advance. Alternatively, a primer layer or the like may be formed. The thickness of the primer layer is usually about 0.001 to 5 μm, preferably 0.01 μm or more, more preferably 4 μm or less, and further preferably 3 μm or less.
If the primer layer is too thick, the appearance of the composite retardation plate 5 tends to be poor.

The viscosity of the active energy ray-curable adhesive is not particularly limited as long as it can be applied by various methods, but the viscosity at 25 ° C. is preferably in the range of 10 to 1,000 mPa · sec. , And more preferably in the range of 20 to 500 mPa · sec. If the viscosity is too low, it tends to be difficult to form a layer with a desired thickness. On the other hand, if the viscosity is too large, it tends to be difficult to flow, and it is difficult to obtain a uniform coating film without unevenness. The viscosity referred to here is a value measured at 10 rpm after adjusting the temperature of the adhesive to 25 ° C. using an E-type viscometer.

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

In the electron beam curing type, any appropriate condition can be adopted as the irradiation condition of the electron beam as long as the active energy beam curing type adhesive can be cured. For example, the electron beam irradiation has an acceleration voltage of preferably 5 kV to 300 kV, more preferably 10 kV to 250 kV. If the accelerating voltage is less than 5 kV, the electron beam may not reach the adhesive and curing may be insufficient. If the accelerating voltage exceeds 300 kV, the penetrating power through the sample is too strong and the electron beam rebounds, and the transparent protective film and The polarizer may be damaged. The irradiation dose is 5 to 100 kGy, more preferably 10 to 75 kGy. If the irradiation dose is less than 5 kGy, the adhesive will be insufficiently cured, and if it exceeds 100 kGy, the retardation layer will be damaged, and the mechanical strength will decrease and yellowing will occur, so that desired optical characteristics cannot be obtained.

Electron beam irradiation is usually performed in an inert gas, but may be performed in the air or under a condition in which oxygen is slightly introduced, if necessary. By appropriately introducing oxygen, oxygen inhibition is intentionally caused on the surface of the retardation layer to which the electron beam first strikes, and damage to the retardation layer can be prevented, and only the adhesive is efficiently irradiated with the electron beam. be able to.

In the ultraviolet curing type, the light irradiation intensity of the active energy ray-curable adhesive is determined depending on the composition of the adhesive and is not particularly limited, but is preferably from 10 to 1,000 mW / cm ² . When the light irradiation intensity on the resin composition is less than 10 mW / cm ² , the reaction time becomes too long, and when it exceeds 1,000 mW / cm ² , heat radiated from a light source and heat generated during polymerization of the composition are generated. , May cause yellowing of the constituent materials of the adhesive. The irradiation intensity is preferably an intensity in a wavelength region effective for activating the cationic photopolymerization initiator, more preferably an intensity in a wavelength region of 400 nm or less, and still more preferably a wavelength region of 280 to 320 nm. Is the strength at Such once with light intensity or by irradiation a plurality of times, the integrated light quantity is preferably 10 mJ / cm ² or more, more preferably set to be 100 ~ 1,000mJ / cm ^2. When the integrated light amount to the adhesive is less than 10 mJ / cm ² , the generation of active species derived from the polymerization initiator is not sufficient, and the curing of the adhesive is insufficient. On the other hand, if the integrated light amount exceeds 1,000 mJ / cm ² , the irradiation time becomes extremely long, which is disadvantageous for improving the productivity. At this time, the wavelength region (UVA (320 to 390 nm) or UVB (280 to 320 nm) or the like) in which the integrated light amount is required differs depending on the type of the film of the retardation layer and the type of the adhesive used.

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

<1/2 wavelength layer, 1/4 wavelength layer>
The 波長 wavelength layer 11 and the 波長 wavelength layer 12 may be composed of only the retardation expression layer as long as they include at least one retardation expression layer, or may be formed together with the retardation expression layer. Other layers may be included. Examples of other layers include a base material layer, an alignment film layer, and a protective layer. The other layers do not affect the value of the retardation. Further, in the present specification, the refractive index of the phase difference layer means the refractive index of the phase difference expression layer regardless of the presence or absence of another layer.

Examples of the retardation expression layer include a layer formed by using a liquid crystal compound (hereinafter, referred to as a “liquid crystal layer”) or a stretched film. The phase difference expression layer is preferably a liquid crystal layer from the viewpoint of reducing the thickness of the polarizing plate composite. In general, the retardation developing layer, which is a liquid crystal layer, is easier to make thinner than the retardation developing layer, which is a stretched film. The thickness of the retardation expression layer is preferably 0.5 μm to 10 μm, and more preferably 0.5 μm to 5 μm. When the 波長 wavelength layer 11 and the 波長 wavelength layer 12 include layers other than the retardation expression layer (base layer, alignment layer, protective layer, etc.), the total thickness is 0.5 μm. The thickness is preferably from 300 μm to 300 μm, more preferably from 0.5 μm to 150 μm.

光学 The optical properties of the retardation layer can be adjusted by the alignment state of the liquid crystal compound constituting the retardation expression layer or the stretching method of the stretched film constituting the retardation expression layer.

(1/2 wavelength layer)
The 波長 wavelength layer 11 gives a phase difference of π (= λ / 2) to the electric field oscillation direction (polarization plane) of the incident light, and has a function of changing the direction (polarization direction) of linearly polarized light. I have. When circularly polarized light is incident, the direction of rotation of the circularly polarized light can be reversed.

The wavelength layer 11 is a layer in which the in-plane retardation value Re (λ) at a specific wavelength λ nm satisfies Re (λ) = λ / 2. Although Re (λ) = λ / 2 may be achieved at any wavelength in the visible light range, it is particularly preferable to achieve Re (λ) at a wavelength of 550 nm. Re (550), which is an in-plane retardation value at a wavelength of 550 nm, preferably satisfies 210 nm ≦ Re (550) ≦ 300 nm. More preferably, 220 nm ≦ Re (550) ≦ 290 nm is satisfied.

The half-wavelength layer 11 preferably has a refractive index (n11 _y ) in the fast axis direction at a wavelength of 589 nm of less than 1.60, and more preferably 1.59 or less.

(1/4 wavelength layer)
The 波長 wavelength layer 12 gives a phase difference of π / 2 (= λ / 4) to the electric field oscillation direction (polarization plane) of the incident light, and converts linearly polarized light of a specific wavelength into circularly polarized light (or It has the function of converting circularly polarized light to linearly polarized light.

The quarter-wave layer 12 is a layer in which the in-plane retardation value Re (λ) at a specific wavelength λ nm satisfies Re (λ) = λ / 4, and is achieved at any wavelength in the visible light region. However, it is preferably achieved at a wavelength of 550 nm. It is preferable that the in-plane retardation value Re (550) at a wavelength of 550 nm satisfies 100 nm ≦ Re (550) ≦ 160 nm. Further, it is more preferable to satisfy 110 nm ≦ Re (550) ≦ 150 nm.

The quarter wavelength layer 12 preferably has an average value of the refractive index (n12 _{x, y} ) at a wavelength of 589 nm of less than 1.58, more preferably 1.57 or less.

(Retardation layer formed from liquid crystal layer)
The case where the retardation expression layer of the retardation layer is a liquid crystal layer will be described. The retardation layer may be a 波長 wavelength layer or a 波長 wavelength layer. FIG. 2 is a schematic cross-sectional view schematically illustrating an example of a retardation layer including a retardation expression layer that is a liquid crystal layer and another layer. As shown in FIG. 2, the retardation layer 30 includes a base layer 31, an alignment layer 32, and a retardation expression layer 33 serving as a liquid crystal layer, which are stacked in this order. The retardation layer is not limited to the retardation layer 30 shown in FIG. 2 as long as the retardation layer includes the retardation expression layer 33 of the liquid crystal layer. Alternatively, the base layer 31 and the alignment layer 32 may be separated from the retardation layer 30 and may be constituted only of the liquid crystal layer. Good. From the viewpoint of thinning, the retardation layer preferably has a configuration in which the base material layer 31 is peeled off, and more preferably has a configuration including only the retardation expression layer 33 of the liquid crystal layer. The base layer 31 has a function as a support layer that supports the alignment layer 32 formed on the base layer 31 and the phase difference expression layer 33 of the liquid crystal layer. The base layer 31 is preferably a film formed of a resin material.

As the resin material, for example, a resin material having excellent transparency, mechanical strength, thermal stability, stretchability, and the like is used. Specifically, polyolefin resins such as polyethylene and polypropylene; cyclic polyolefin resins such as norbornene polymers; polyester resins such as polyethylene terephthalate and polyethylene naphthalate; (meth) acrylic acid, polymethyl (meth) acrylate and the like (Meth) acrylic acid resin; cellulose ester resin such as triacetyl cellulose, diacetyl cellulose and cellulose acetate propionate; vinyl alcohol resin such as polyvinyl alcohol and polyvinyl acetate; polycarbonate resin; polystyrene resin; Arylate resin; polysulfone resin; polyether sulfone resin; polyamide resin; polyimide resin; polyether ketone resin; polyphenylene sulfide resin; Ren'okishido resins, and mixtures thereof, may be mentioned copolymer and the like. Among these resins, it is preferable to use any of a cyclic polyolefin-based resin, a polyester-based resin, a cellulose ester-based resin, and a (meth) acrylic acid-based resin, or a mixture thereof. The “(meth) acrylic acid” means “at least one of acrylic acid and methacrylic acid”.

The base material layer 31 may be a single layer obtained by mixing one or two or more of the above resins, or may have a multilayer structure of two or more layers. When it has a multilayer structure, the resin forming each layer may be the same or different.

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

Although the thickness of the base material layer 31 is not particularly limited, it is generally preferably 5 to 200 μm, more preferably 10 to 200 μm, and more preferably 10 to 150 μm from the viewpoint of workability such as strength and handleability. It is more preferred that there be.

In order to improve the adhesion between the base layer 31 and the alignment layer 32, at least the surface of the base layer 31 on which the alignment layer 32 is formed may be subjected to corona treatment, plasma treatment, flame treatment, or the like, A primer layer or the like may be formed. When the base layer 31 or the base layer 31 and the alignment layer 32 are separated to form a retardation layer, the separation can be facilitated by adjusting the adhesion at the separation interface.

The alignment layer 32 has an alignment regulating force for causing the liquid crystal compound included in the phase difference expression layer 33 of the liquid crystal layer formed on the alignment layer 32 to perform liquid crystal alignment in a desired direction. Examples of the alignment layer 32 include an alignment polymer layer formed of an alignment polymer, a photo alignment polymer layer formed of a photo alignment polymer, and a grub alignment layer having a concavo-convex pattern or a plurality of groves (grooves) on the layer surface. be able to. The thickness of the alignment layer 32 is usually 0.01 to 10 μm, preferably 0.01 to 5 μm.

The oriented polymer layer can be formed by applying a composition in which the oriented polymer is dissolved in a solvent to the base layer 31 to remove the solvent, and performing a rubbing treatment as needed. In this case, the alignment regulating force can be arbitrarily adjusted depending on the surface state of the alignment polymer and the rubbing conditions in the alignment polymer layer formed of the alignment polymer.

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

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

The phase difference expression layer 33 which is a liquid crystal layer gives a predetermined phase difference to light, and examples thereof include a phase difference expression layer for a １／ wavelength layer and a phase difference expression layer for a 波長 wavelength layer. be able to.

The retardation layer 33, which is a liquid crystal layer, can be formed using a known liquid crystal compound.
The type of the liquid crystal compound is not particularly limited, and a rod-shaped liquid crystal compound, a disc-shaped liquid crystal compound, and a mixture thereof can be used. The liquid crystal compound may be a polymer liquid crystal compound, a polymerizable liquid crystal compound, or a mixture thereof. Examples of the liquid crystal compound include, for example, JP-A-11-513019, JP-A-2005-289980, JP-A-2007-108732, JP-A-2010-244038, JP-A-2010-31223, and JP-A-2010-31223. Liquid crystal compounds described in JP-A-2010-270108, JP-A-2011-6360, JP-A-2011-207765, JP-A-2016-81035, WO2017 / 043438 and JP-T-2011-207765. Is mentioned.

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

(Retardation layer provided with stretched film as retardation expression layer)
The case where the retardation developing layer is a stretched film will be described. A stretched film is usually obtained by stretching a substrate. As a method of stretching the base material, for example, a roll (winding body) in which the base material is wound on a roll is prepared, and the base material is continuously unwound from the winding body and unwound. The substrate is transferred to a heating furnace. The set temperature of the heating furnace is in the range of around the glass transition temperature of the substrate (° C.) to [glass transition temperature + 100] (° C.), preferably around the glass transition temperature (° C.) to [glass transition temperature + 50] (° C.). Range. In the heating furnace, when stretching in the direction of travel of the substrate, or in a direction perpendicular to the direction of travel, the uniaxial or biaxial thermal stretching process is performed by adjusting the transport direction and tension and tilting at an arbitrary angle. Do. The stretching ratio is usually 1.1 to 6 times, preferably 1.1 to 3.5 times.

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

The substrate is usually a transparent substrate. The transparent substrate means a substrate having transparency capable of transmitting light, in particular, visible light, and transparency refers to a property of having a transmittance of 80% or more to a light beam having a wavelength of 380 to 780 nm. Say. A specific example of the transparent substrate is a light-transmitting resin substrate. Examples of the resin constituting the light-transmitting resin substrate include polyolefins such as polyethylene and polypropylene; cyclic olefin resins such as norbornene-based polymers; polyvinyl alcohol; polyethylene terephthalate; polymethacrylic acid esters; Cellulose esters such as diacetylcellulose and cellulose acetate propionate; polyethylene naphthalate; polycarbonate; polysulfone; polyethersulfone; polyetherketone; polyphenylene sulfide and polyphenylene oxide. From the viewpoint of availability and transparency, polyethylene terephthalate, polymethacrylate, cellulose ester, cyclic olefin-based resin or polycarbonate is preferred.

Cellulose esters are those in which some or all of the hydroxyl groups contained in cellulose are esterified, and can be easily obtained from the market. Further, a cellulose ester base material can be easily obtained from the market. Examples of commercially available cellulose ester base materials include “Fujitac (registered trademark) film” (Fujifilm Corporation); “KC8UX2M”, “KC8UY” and “KC4UY” (Konica Minolta Opto Co., Ltd.) and the like. .

Polymethacrylate and polyacrylate (hereinafter, polymethacrylate and polyacrylate may be collectively referred to as a (meth) acrylic resin.
) Is readily available from the market.

Examples of the (meth) acrylic resin include a homopolymer of an alkyl methacrylate or an alkyl acrylate, and a copolymer of an alkyl methacrylate and an alkyl acrylate. Specific examples of the alkyl methacrylate include methyl methacrylate, ethyl methacrylate, and propyl methacrylate, and specific examples of the alkyl acrylate include methyl acrylate, ethyl acrylate, and propyl acrylate. As the (meth) acrylic resin, those commercially available as general-purpose (meth) acrylic resins can be used. What is called an impact-resistant (meth) acrylic resin may be used as the (meth) acrylic resin.

のため In order to further improve the mechanical strength, it is also preferable to include rubber particles in the (meth) acrylic resin. The rubber particles are preferably acrylic. Here, the acrylic rubber particles have rubber elasticity obtained by polymerizing an acrylic monomer mainly containing an alkyl acrylate such as butyl acrylate or 2-ethylhexyl acrylate in the presence of a polyfunctional monomer. Particles. The acrylic rubber particles may be such that the particles having rubber elasticity are formed in a single layer, or may be a multilayer structure having at least one rubber elastic layer. Acrylic rubber particles having a multilayer structure include particles having the above rubber elasticity as a nucleus, the periphery of which is covered with a hard alkyl methacrylate polymer, and a hard alkyl methacrylate polymer. A core and its surroundings covered with an acrylic polymer having rubber elasticity as described above.Also, the periphery of the hard cores is covered with a rubber elastic acrylic polymer, and further around the hard alkyl methacrylate. And those covered with a polymer. The average diameter of the rubber particles formed by the elastic layer is usually in the range of about 50 to 400 nm.

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

Cyclic olefin resin can be easily obtained from the market. Commercially available cyclic olefin-based resins include “Topas” (registered trademark) [Ticona (Germany)], “ARTON” (registered trademark) [JSR Corporation], “ZEONOR” (registered trademark) [Japan] Zeon Corporation], “ZEONEX” (registered trademark) [Zeon Corporation] and “Apel” (registered trademark) [Mitsui Chemicals]. Such a cyclic olefin-based resin can be used as a substrate by forming a film by known means such as a solvent casting method and a melt extrusion method. Alternatively, a commercially available cyclic olefin-based resin substrate can be used. Commercially available cyclic olefin resin base materials include "ESCINA" (registered trademark) [Sekisui Chemical Co., Ltd.], "SCA40" (registered trademark) [Sekisui Chemical Co., Ltd.], and "ZEONOA FILM" (registered trademark). ) [OPTES CORPORATION] and "ARTON FILM" (registered trademark) [JSR Corporation].

When the cyclic olefin-based resin is a copolymer of a cyclic olefin and a chain olefin or an aromatic compound having a vinyl group, the content of the structural unit derived from the cyclic olefin is defined as the total structural units of the copolymer. On the other hand, it is usually 50 mol% or less, preferably 15 to 50 mol%. Examples of the chain olefin include ethylene and propylene, and examples of the aromatic compound having a vinyl group include styrene, α-methylstyrene, and alkyl-substituted styrene. When the cyclic olefin-based resin is a ternary copolymer of a cyclic olefin, a chain olefin, and an aromatic compound having a vinyl group, the content ratio of the structural unit derived from the chain olefin is the same as that of the copolymer. The content of the structural unit derived from the aromatic compound having a vinyl group is usually 5 to 80 mol% with respect to all the structural units. It is. Such a terpolymer has the advantage that, in its production, the amount of expensive cyclic olefins can be relatively reduced.

<Linear polarizing plate>
The linear polarizing plate 13 may be a film having a polarizing function of obtaining linearly polarized light from transmitted light. Examples of the film include a stretched film on which a dye having absorption anisotropy is adsorbed, a film including a film coated with a dye having absorption anisotropy as a polarizer, and the like. Examples of the dye having absorption anisotropy include dichroic dyes. Examples of the film to which a dye having absorption anisotropy is applied, which is used as a polarizer, include a stretched film on which a dye having absorption anisotropy is adsorbed, a composition containing a dichroic dye having liquid crystallinity, and Examples include a film having a liquid phase layer obtained by applying a composition containing a colorant and a polymerizable liquid crystal.

(Linear polarizing plate with stretched film as polarizer)
A linear polarizing plate including, as a polarizer, a stretched film on which a dye having absorption anisotropy is adsorbed will be described. A stretched film on which a dye having absorption anisotropy is adsorbed, which is a polarizer, is usually formed by uniaxially stretching a polyvinyl alcohol-based resin film, and dyeing the polyvinyl alcohol-based resin film with a dichroic dye. It is manufactured through a step of adsorbing the dichroic dye, a step of treating the polyvinyl alcohol-based resin film to which the dichroic dye is adsorbed with a boric acid aqueous solution, and a step of washing with water after the treatment with the boric acid aqueous solution. Such a polarizer may be used as it is as a linear polarizer, or a polarizer obtained by attaching a transparent protective film to at least one surface of the polarizer may be used as a linear polarizer.

偏光 Thus, the thickness of the polarizer obtained by subjecting the polyvinyl alcohol-based resin film to uniaxial stretching, dyeing with a dichroic dye, boric acid treatment, washing with water and drying is preferably 5 to 40 μm.

The material of the protective film to be bonded to one or both surfaces of the polarizer is not particularly limited, for example, cyclic polyolefin resin film, triacetyl cellulose, cellulose acetate based resin such as diacetyl cellulose Films known in the art, such as resin films, polyester resin films made of resins such as polyethylene terephthalate, polyethylene naphthalate, and polybutylene terephthalate, polycarbonate resin films, (meth) acrylic resin films, and polypropylene resin films. Can be mentioned. The thickness of the protective film is usually 300 μm or less, preferably 200 μm or less, more preferably 50 μm or less, and usually 5 μm or more and preferably 20 μm or more from the viewpoint of thinning. . Further, the protective film on the viewing side may have a phase difference or may not have a phase difference. On the other hand, the protective film on the side laminated on the half-wavelength layer 11 preferably has a retardation of 10 nm or less.

(Linear polarizing plate provided with a film having a liquid crystal layer as a polarizer)
A linear polarizing plate including a film having a liquid crystal layer as a polarizer will be described. Used as a polarizer, as a film coated with a dye having absorption anisotropy, a composition containing a dichroic dye having liquid crystallinity, or a composition containing a dichroic dye and a liquid crystal compound And the resulting film. The film may be used alone as a linear polarizing plate, or may be used as a linear polarizing plate in a configuration having a protective film on one or both sides thereof. Examples of the protective film include the same as the linear polarizing plate including the above-described stretched film as a polarizer.

フィルム Thin films coated with a dye having absorption anisotropy are preferred to be thin, but if too thin, strength tends to decrease and processability tends to be poor. The thickness of the film is usually 20 μm or less, preferably 5 μm or less, more preferably 0.5 μm or more and 3 μm or less.

フィルム Specific examples of the film coated with the dye having absorption anisotropy include the films described in JP-A-2012-33249.

The dye having the absorption anisotropy may be directly applied to the half-wavelength layer 11 to form a polarizing plate composite. In this case, there is no need to provide the second adhesive layer 22.

<Second adhesive layer>
The second adhesive layer 22 can be composed of, for example, an adhesive, a water-based adhesive, an active energy ray-curable adhesive, and a combination thereof. In the present specification, the term "second adhesive layer" includes not only an adhesive layer made of an adhesive but also an adhesive layer made of an adhesive.

活性 The description of the first adhesive layer 21 applies to the active energy ray-curable adhesive forming the second adhesive layer 22. When the first adhesive layer 21 and the second adhesive layer 22 are formed from an active energy ray-curable adhesive, the first adhesive layer 21 and the second adhesive layer 22 are formed from the same active energy ray-curable adhesive. Alternatively, it may be formed from a different active energy ray-curable adhesive. The refractive index n22 of the second adhesive layer 22 at a wavelength of 589 nm is preferably less than 1.55.

<Other layers>
The polarizing plate composite may have layers other than those described above. For example, it may have a retardation layer for optical compensation, and may have a third adhesive layer other than the first adhesive layer 21 and the second adhesive layer 22. The third adhesive layer is, for example, an adhesive layer provided on the surface of the ４ wavelength layer 12 on the side opposite to the first adhesive layer 21, and is used for bonding the polarizing plate composite to the image display panel. Can be used.

[Production method of polarizing plate composite]
FIGS. 3A to 3D are schematic cross-sectional views schematically showing one example of the method for producing a polarizing plate composite of the present invention. The half-wavelength layer 11 including the first retardation expression layer 113, the first alignment layer 112, and the first base layer 111 as illustrated in FIG. 3A, and the second wavelength layer 11 as illustrated in FIG. The composite retardation plate 40 is obtained by laminating the retardation expression layer 123, the second alignment layer 122, and the 波長 wavelength layer 12 including the first base material layer 121 via the first adhesive layer 21. As shown in FIG. 3C, for example, the composite retardation plate 40 includes a first base material layer 111, a first alignment layer 112, a first retardation expression layer 113, a first adhesive layer 21, and a second retardation layer. This is a laminate in which the expression layer 123, the second alignment layer 122, and the second base layer 121 are laminated in this order. After that, as shown in FIG. 3D, the linear polarizing plate 13 is laminated on the half-wavelength layer 11 side via the second adhesive layer 22 to obtain the polarizing plate composite 10.

The 波長 wavelength layer 11 and the 波長 wavelength layer 12 may be arranged such that the phase difference expression layers 113 and 123 are located inside or outside, but FIG. As shown in (C) and (D), it is preferable that the phase difference expression layers 113 and 123 are arranged so as to be located inside and in contact with the first adhesive layer 21.

As a method of bonding the 波長 wavelength layer 11 and the 波長 wavelength layer 12, the bonding surface of the 波長 wavelength layer 11 or the bonding surface of the 波長 wavelength layer 12, or both, The active energy ray-curable adhesive constituting the first adhesive layer 21 is applied, and the other bonding surface is laminated thereon. Then, the active layer is activated from the 波長 wavelength layer 11 or the 波長 wavelength layer 12 side. A method of curing the adhesive by irradiating with energy rays may be used. Various coating methods such as a doctor blade, a wire bar, a die coater, a comma coater, and a gravure coater can be used for coating the adhesive forming the first adhesive layer 21.

Either or both of the bonding surface of the 波長 wavelength layer 11 and the bonding surface of the ４ wavelength layer 12 may be subjected to a corona treatment, a plasma treatment, or a primer layer. .

The composite retardation plate 40 may be a laminate as shown in FIG. 3C or a laminate in which at least one of the first base layer 111 and the second base layer 121 is peeled off. You may. Further, a stacked body in which the first base material layer 111 and the first alignment layer 112 are separated from the stacked body illustrated in FIG. 3C may be used, or a second stacked body may be formed from the stacked body illustrated in FIG. It may be a laminate in which the material layer 121 and the second alignment layer 122 are separated. 4A and 4B show specific examples.

FIGS. 4A and 4B are schematic cross-sectional views schematically showing another example of a method for manufacturing a polarizing plate composite from the composite retardation plate 40 shown in FIG. 3C. As shown in FIG. 4A, the first base layer 111 and the first alignment layer 112, the second base layer 121, and the second alignment layer 122 are formed from the composite retardation plate 40 shown in FIG. By peeling off, a composite retardation plate 40 'was obtained. Thereafter, as shown in FIG. 4B, the second adhesive layer 22 was interposed on the half-wavelength layer 11 (first retardation expression layer 113) side. The polarizing plate composite 10 is obtained by stacking the linear polarizing plates 13.

[Use of polarizing plate composite]
The polarizing plate composite, which is a circular polarizing plate, can be used in various image display devices as an optical laminate that is disposed on the viewing side of the image display panel and imparts antireflection performance. An image display device is a device having an image display panel, and includes a light emitting element or a light emitting device as a light emitting source. Examples of the image display device include a liquid crystal display device, an organic electroluminescence (EL) display device, an inorganic electroluminescence (EL) display device, a touch panel display device, an electron emission display device (for example, a field emission display (FED), a surface field emission display). Device (SED)), electronic paper (display device using electronic ink or electrophoretic element, plasma display device, projection display device (for example, display having grating light valve (GLV) display device, digital micromirror device (DMD)) Devices) and piezoelectric ceramic displays, etc. Examples of the liquid crystal display device include a transmission type liquid crystal display device, a transflective type liquid crystal display device, a reflection type liquid crystal display device, a direct-view type liquid crystal display device, and a projection type liquid crystal display device. These image display devices display two-dimensional images. In particular, the optical laminate, which is a circularly polarizing plate, may include an image display panel having a bent portion, and may be a three-dimensional image display device that displays a three-dimensional image. It can be effectively used for a luminescence (EL) display device.

Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples, but the present invention is not limited to these examples. Hereinafter, parts and percentages representing the amounts used and contents are based on mass unless otherwise specified.

[Adjustment of active energy ray-curable adhesive]
The components shown below were mixed at the mixing ratio (unit: parts by mass) shown in Table 1, and then defoamed to prepare adhesives A to F. The cationic polymerization initiator (B) was blended as a 50% by mass propylene carbonate solution, and Table 1 shows the solid content.

(Epoxy compound)
A-1: 3 ', 4'-epoxycyclohexylmethyl 3,4-epoxycyclohexanecarboxylate (trade name: CEL2021P, manufactured by Daicel Corporation)
A-2: Bisphenol F type epoxy resin (trade name: EXA-830CRP, manufactured by DIC Corporation)
A-3: Fluorene type epoxy resin (trade name: OGSOL EG-200, manufactured by Osaka Gas Chemical Co., Ltd.)
A-4: DCPDM type epoxy resin (trade name: EP-4088S, manufactured by ADEKA Corporation)
A-5: Neopentyl glycol diglycidyl ether (trade name: EX-211L, manufactured by Nagase ChemteX Corporation)
A-6: Biphenyl type epoxy resin (trade name: EX-142, manufactured by Nagase ChemteX Corporation)
A-7: 2-ethylhexyl glycidyl ether (trade name: EX-121, manufactured by Nagase ChemteX Corporation)

(Initiator)
B: Cationic polymerization initiator (trade name: CPI-100P, manufactured by San Apro Co., Ltd., 50% by mass solution)

(Refractive index measurement method)
The adhesive prepared above was coated on one side of a stretched norbornene-based resin film [“Zeonor Film” manufactured by Nippon Zeon Co., Ltd.] using a bar coater [manufactured by Daiichi Rika Co., Ltd.]. A cured product was obtained by irradiating ultraviolet rays with an integrated light amount of 600 mJ / cm ² (UV-B) using [Fusion UV Systems Co., Ltd.]. The film thickness of the obtained cured product was about 30 μm.
The norbornene-based resin film is peeled from the obtained cured product, and the refractive index (589 nm) of the cured product layer is measured at 25 ° C. using a multi-wavelength Abbe refractometer (“DR-M2” manufactured by Atago Co., Ltd.). did. Table 1 shows the results.

[Manufacture of polarizing plate]
After dipping a polyvinyl alcohol film having an average degree of polymerization of about 2,400 and a saponification degree of 99.9 mol% or more and a thickness of 75 μm in pure water at 30 ° C., the mass ratio of iodine / potassium iodide / water is 0.1%. It was immersed in an aqueous solution of 02/2/100 at 30 ° C. to perform iodine dyeing (iodine dyeing step). The polyvinyl alcohol film having undergone the iodine dyeing step was immersed in an aqueous solution of potassium iodide / boric acid / water having a mass ratio of 12/5/100 at 56.5 ° C. to perform boric acid treatment (boric acid treatment step). ).

The polyvinyl alcohol film having undergone the boric acid treatment step was washed with pure water at 8 ° C., and then dried at 65 ° C. to obtain a polarizer in which iodine was adsorbed and oriented in polyvinyl alcohol. At this time, stretching was performed in the iodine dyeing step and the boric acid treatment step. The total stretching ratio in such stretching was 5.3 times, and the thickness of the obtained polarizer was 27 μm.

A saponified triacetyl cellulose film (trade name: KC4UYTAC, manufactured by Konica Minolta, thickness: 40 μm) was bonded to both sides of the obtained polarizer with a nip roll via an aqueous adhesive. The obtained bonded product was dried at 60 ° C. for 2 minutes while keeping the tension of 430 N / m to obtain a polarizing plate having a triacetyl cellulose film as a protective film on both sides. The above-mentioned water-based adhesive is obtained by adding 100 parts of water, 3 parts of a carboxyl group-modified polyvinyl alcohol (Kuraray Povar KL318, manufactured by Kuraray), and a water-soluble polyamide epoxy resin (Sumilez Resin 650, manufactured by Sumika Chemtex, solid content concentration). It was prepared by adding 1.5 parts of a (30% aqueous solution).

[Production of 1/2 Wavelength Layer]
The λ / 2 alignment treatment was performed by applying a coating liquid for an alignment film on a transparent resin substrate and drying. Next, a coating liquid containing a discotic liquid crystal compound is applied to the alignment surface, and the alignment of the liquid crystal compound is fixed by heating and UV irradiation, whereby a 2 μm thick retardation expression layer is formed on the transparent resin substrate. Was prepared. The obtained half-wave layer has a refractive index n11 _y in the fast axis direction at a wavelength of 589 nm of 1.50, a refractive index n11 _{x in the} slow axis direction of 1.62, and a refractive index n11 in the thickness direction. _z was 1.62. The three-dimensional average refractive index n11 _{x, y, z} calculated from the three refractive indices n11 _x , n11 _y , and n11 _z is 1.58, and the in-plane average refractive index calculated from the two in-plane refractive indices n11 _x , n11 _y. The ratio was n11 _{x and y} was 1.56.

[Manufacture of 1/4 wavelength layer]
A λ / 4 alignment treatment was performed by applying a coating liquid for an alignment film on a transparent resin substrate and drying it. Next, a 1 μm thick retardation expression layer is formed on the transparent resin substrate by applying a coating liquid containing a polymerizable nematic liquid crystal monomer in a rod shape on the alignment surface and solidifying the coating liquid while maintaining the refractive index anisotropy. A quarter wavelength layer having the following formula: Refractive index n12 _y of the fast axis direction at a wavelength of 589nm obtained 1/4 wavelength layer is 1.49, the refractive index n12 _x in the slow axis direction is 1.60, the thickness direction refractive index n12 _z was 1.49. The three-dimensional average refractive index n12 _{x, y, z} calculated from the three refractive indices n12 _x , n12 _y , and n12 _z is 1.53, and the surface calculated from the two in-plane refractive indices n12 _x , n12 _y. The inner average refractive index n12 _{x, y} was 1.55.

<Example 1>
Corona treatment was applied to the obtained retardation developing layer of the 波長 wavelength layer and the retardation developing layer of the 波長 wavelength layer. The adhesive A shown in Table 1 was applied to the corona-treated quarter-wave retardation layer, and the corona-treated half-wave layer was adjusted so that the retardation-developing layer side faces the half-wave layer. The two-wavelength layer was laminated and bonded with a laminator to obtain a laminate. At this time, they were bonded so that the angle between the slow axis of the 波長 wavelength layer and the slow axis of the 波長 wavelength layer was 60 °.
An ultraviolet ray was irradiated from the quarter-wave layer of the laminate using an ultraviolet ray irradiator (manufactured by Fusion UV Systems Co., Ltd.) with an integrated light amount of 400 mJ / cm ² (UV-B), and the adhesive was cured. A composite retardation plate having a laminated structure of “/ 4 wavelength layer” / first adhesive layer / “1/2 wavelength layer” was obtained. The thickness of the first adhesive layer was 1.5 μm.
The alignment film and the transparent resin substrate of the 波長 wavelength layer of the obtained composite retardation plate are peeled off, and the above-mentioned polarizing plate and the 差 wavelength layer's retardation expression layer are bonded together using an acrylic adhesive. did. The thickness of the acrylic pressure-sensitive adhesive (the thickness of the second adhesive layer) was 5 μm, and the angle between the transmission axis of the polarizing plate and the fast axis of the １／ wavelength layer (“axis angle” in Table 1). ) Was 15 °.
Next, the alignment film and the transparent resin substrate on the １／ wavelength layer side are peeled off, and a laminate of polarizing plate / second adhesive layer / “１／ wavelength layer” / first adhesive layer / “１／ wavelength layer” is formed. A polarizing plate composite having a structure was obtained.

<Example 2>
A polarizing plate composite was produced in the same manner as in Example 1, except that the adhesive B was used as the adhesive for forming the first adhesive layer.

<Example 3>
A polarizing plate composite was produced in the same manner as in Example 1, except that the adhesive C was used as an adhesive for forming the first adhesive layer.

<Example 4>
A polarizing plate composite was produced in the same manner as in Example 1, except that the adhesive D was used as an adhesive for forming the first adhesive layer.

<Comparative Example 1>
A polarizing plate composite was produced in the same manner as in Example 1, except that the adhesive E was used as an adhesive for forming the first adhesive layer.

<Comparative Example 2>
A polarizing plate composite was produced in the same manner as in Example 1 except that the adhesive F was used as an adhesive for forming the first adhesive.

<Comparative Example 3>
Polarization was performed in the same manner as in Example 1 except that the polarizing plate was bonded so that the angle formed by the transmission axis of the polarizing plate and the fast axis of the half-wave layer (referred to as “axial angle” in Table 1) was 105 °. A plate composite was prepared.

[Evaluation methods]
(Interference unevenness evaluation method)
The polarizing plate composites of Examples and Comparative Examples were attached to an aluminum reflecting plate via an acrylic pressure-sensitive adhesive (25 μm in thickness), visually observed under a three-wavelength fluorescent lamp, and evaluated based on the following criteria. .
Table 2 shows the evaluation results.
A: interference unevenness is not visually recognized B: interference unevenness is slightly recognized C: interference unevenness is visually recognized

10 ° polarizing plate composite, 11 half-wave layer, 12 波長 quarter-wave layer, 13 linear polarizing plate, 21 first adhesive layer, 22 second adhesive layer, 30 retardation plate, 31 base layer, 32 orientation layer , 33 ° retardation developing layer, 40 ° composite retardation plate, 111 ° first base layer, 112 ° first alignment layer, 113 ° first phase difference developing layer, 121 ° second base layer, 122 ° second alignment layer, 123 ° second Retardation expression layer.

Claims

A linear polarizing plate, a 波長 wavelength layer, a first adhesive layer obtained by curing an active energy ray-curable adhesive, and a 波長 wavelength layer, in this order,
The angle between the fast axis of the １／ wavelength layer and the transmission axis of the linear polarizer is 10 ° or more and 20 ° or less,
The polarizing plate composite, wherein the absolute value of the difference between the refractive index of the first adhesive layer at a wavelength of 589 nm and the refractive index of the 波長 wavelength layer in the fast axis direction at a wavelength of 589 nm is less than 0.05. .
偏光 The polarizing plate composite according to claim 1, wherein the first adhesive layer has a refractive index at a wavelength of 589 nm of less than 1.55.
The 1/4 wavelength layer has an in-plane average refractive index of less than 1.58, which is an average value of a refractive index in a fast axis direction and a refractive index in a slow axis direction at a wavelength of 589 nm. 3. The polarizing plate composite according to item 1.
The in-plane average refractive index, which is the average value of the refractive index of the first adhesive layer at a wavelength of 589 nm and the refractive index of the quarter wavelength layer at a wavelength of 589 nm in the fast axis direction and the slow axis direction. The polarizing plate composite according to any one of claims 1 to 3, wherein the absolute value of the difference from the polarizing plate is less than 0.05.
The polarizing plate composite according to any one of claims 1 to 4, which is a circular polarizing plate.
(6) The polarizing plate composite according to any one of (1) to (5) above, wherein the half-wavelength layer includes a retardation developing layer that is a liquid crystal layer.
The polarizing plate composite according to any one of claims 1 to 6, wherein the 波長 wavelength layer includes a retardation developing layer that is a liquid crystal layer.
偏光 The polarizing plate composite according to any one of claims 1 to 7, wherein the first adhesive layer has a thickness of 5 μm or less.
画像 An image display device comprising: an image display panel; and the polarizing plate composite according to claim 1 disposed on a viewing side of the image display panel.
The image display device according to claim 9, wherein the polarizing plate composite is arranged in a direction in which the linear polarizing plate is located on the viewing side.
The image display device according to claim 9 or 10, wherein the image display device is an organic electroluminescence display device.