JP5985145B2 - Optical laminate and method for producing the same - Google Patents

Description

  The present invention relates to an optical laminate used for a liquid crystal display device, and more specifically, a polarizing plate is laminated on a liquid crystal cell substrate made of glass, plastic sheet or the like constituting the liquid crystal display device via an adhesive layer. The present invention relates to an optical laminate. The present invention also relates to a method for producing the optical laminate.

  A polarizing plate is useful as an optical component constituting a liquid crystal display device, and has traditionally traditionally been configured by laminating a protective layer made of a transparent resin film on one or both sides of a polarizing film using an aqueous adhesive or the like. Has been used. As such a transparent resin film, a triacetyl cellulose film is often used because of its excellent optical transparency and moisture permeability. Even when the protective layer is provided only on one side of the polarizing film, a resin film having an optical function such as a retardation function is provided on the other side of the polarizing film, which also serves as a protective function for the polarizing film. It is often laminated via. The polarizing plate configured as described above is bonded to a liquid crystal cell with an adhesive via another optical function layer as necessary, and is assembled into a liquid crystal display device as a liquid crystal panel.

  Applications of liquid crystal display devices are rapidly expanding as thin display screens such as liquid crystal televisions, liquid crystal monitors, and personal computers. In such expansion of applications, further reduction in thickness is also required for members constituting the same. As described above, a polarizing plate is generally bonded to a liquid crystal cell using an adhesive, but this can be easily removed from the liquid crystal cell and bonded to another polarizing plate if there is any problem after bonding. Because it is convenient to match. However, the pressure-sensitive adhesive usually needs to have a thickness of at least about 20 μm in order to maintain an appropriate pressure-sensitive adhesive force, which is a bottleneck in reducing the thickness of a liquid crystal panel or a liquid crystal display device.

  There is also an attempt to reduce the thickness of the polarizing film by omitting the liquid crystal cell side protective layer, forming an adhesive layer directly on the polarizing film, and bonding the adhesive layer to the liquid crystal cell. However, in such a state where the polarizing film and the liquid crystal cell are directly bonded with the pressure-sensitive adhesive layer, when the heat resistance test exposed to high temperature is performed, the pressure-sensitive adhesive layer alone cannot sufficiently absorb the contraction of the polarizing film, In some cases, floating or peeling occurs between the polarizing film and the pressure-sensitive adhesive layer, resulting in defects such as foaming. In addition, when a thermal shock test (heat shock test) that repeats a high temperature state and a low temperature state was performed, the expansion and contraction of the polarizing film could not be sufficiently absorbed by the adhesive layer alone, and the polarizing film could break. .

  As another attempt to reduce the thickness of the polarizing plate, for example, in Japanese Patent No. 4306269 (Patent Document 1), an uncured film is formed on at least one surface of a polarizing film in which a dichroic dye is adsorbed and oriented on a polyvinyl alcohol resin. A technique for forming a protective film by applying an epoxy resin composition and then curing the composition is disclosed. However, in a state where a polarizing plate having a cured product of an epoxy resin composition as a protective film is bonded to a liquid crystal cell via an adhesive, durability is not sufficient, for example, when a heat shock test is performed, The polarizing film sometimes broke. In addition, in Japanese Patent No. 4306270 (Patent Document 2), an adhesive composed of a composition mainly composed of an epoxy resin not containing an aromatic ring is applied to a polarizing film in which a dichroic dye is adsorbed and oriented on a polyvinyl alcohol resin. The technique which bonds a protective film through an agent and makes it a polarizing plate is disclosed.

  On the other hand, in Japanese Patent No. 4326268 (Patent Document 3), a protective film containing a cured product obtained by polymerizing a photopolymerizable compound is disposed on a polarizer film obtained by dyeing a uniaxially stretched film of a polyvinyl alcohol resin with iodine. A technique relating to a polarizing plate in which a benzotriazole-based ultraviolet absorber is added to the protective film in an amount of 5 to 15 parts by weight with respect to 100 parts by weight of the photopolymerizable compound is disclosed.

Japanese Patent No. 4306269 (Japanese Patent Laid-Open No. 2004-245924) Japanese Patent No. 4306270 (Japanese Patent Laid-Open No. 2004-245925) Japanese Patent No. 4326268 (Japanese Patent Laid-Open No. 2005-10329)

  First, the present inventors have prepared a dichroic dye on a polyvinyl alcohol resin via an adhesive layer formed from an active energy ray-curable resin composition mainly composed of an epoxy compound on a liquid crystal cell substrate. It has been found that by laminating a polarizing plate having an adsorbed and oriented polarizing film, an optical laminate can be obtained that is thin and lightweight and also has excellent durability performance, and a patent application was filed as Japanese Patent Application No. 2009-142108. ing. Using this technology, when a polarizing plate is bonded to a liquid crystal cell substrate via an adhesive composed of an active energy ray-curable resin composition, irradiation of active energy rays for curing the adhesive is performed on the liquid crystal cell side. If performed from the above, the liquid crystal cell may be defective, for example, the orientation of the liquid crystal molecules sealed in the liquid crystal cell may be misaligned. Therefore, the irradiation surface of the active energy ray is limited to the polarizing plate side.

  However, if the polarizing plate does not have the ability to absorb ultraviolet rays even when the active energy ray is irradiated from the polarizing plate side, the active energy ray irradiated from the polarizing plate side reaches the liquid crystal cell, and the liquid crystal cell is the same as above. May cause problems. On the other hand, it is conceivable to impart ultraviolet absorbing ability to the polarizing plate by means such as containing an ultraviolet absorber in any of the films constituting the polarizing plate, thereby suppressing the amount of transmission of active energy rays. In such a case, the active energy ray reaching the adhesive becomes too weak, and the adhesive may not be cured.

  Thus, the object of the present invention is to laminate a polarizing plate and a liquid crystal cell substrate via an active energy ray-curable adhesive to obtain an optical laminate excellent in thin and light weight and durability, and on the polarizing plate side. The active energy rays irradiated from the above are consumed in the stage of curing the adhesive, so that the liquid crystal molecules constituting the liquid crystal cell are not affected. Another object of the present invention is to provide a method for advantageously producing such an optical laminate.

  According to the present invention, a liquid crystal cell substrate and a polarizing plate having a polarizing film having a dichroic dye adsorbed and oriented on a polyvinyl alcohol-based resin are bonded via an adhesive layer, and the adhesive layer Contains an epoxy compound having at least one epoxy group in the molecule, and further contains 0.1 to 20 parts by weight of an ultraviolet absorber per 100 parts by weight of the solid content of the composition. An optical laminate that is a cured product of the composition is provided.

  In this optical laminate, the active energy ray-curable resin composition forming the adhesive layer may contain an oxetane compound in addition to the above-described epoxy compound and ultraviolet absorber. The adhesive layer is preferably 10 μm or less in thickness.

Polarizer constituting the optical laminate state, and are those having a thickness of 100 [mu] m or less, which is that Do advantageous in terms of thin lightweight. This polarizing plate, a transparent protective layer on one surface of the polarizing fill beam described above comprising a cured product of a thermoplastic resin film or the active energy ray curable resin composition, on the opposite side of the transparent protective layer of the polarizing film in terms, because it is stuck to the liquid crystal cell substrate via the adhesive layer of the above organic interest and ing in still terms thin lightweight.

Furthermore, according to the present invention, a transparent protective layer made of a cured product of a thermoplastic resin film or an active energy ray curable resin composition is laminated on one side of a polarizing film in which a dichroic dye is adsorbed and oriented on a polyvinyl alcohol resin. the surface of the polarizing film of the polarizing plate, at least one contains an epoxy compound having an epoxy group, further composition of 100 parts by weight of the solid content, per 0.1 to 20 parts by weight of the ultraviolet absorber in the molecule A step of forming a layer of an active energy ray-curable resin composition containing, a step of bonding a layer of the curable resin composition formed on the surface of the polarizing film to the liquid crystal cell substrate, and a liquid crystal cell substrate Also provided is a method for producing an optical laminate comprising a step of irradiating active energy rays from the bonded polarizing plate side to cure the layer of the curable resin composition to form an adhesive layer. It is.

  The optical layered body of the present invention contributes to reducing the thickness and weight of the liquid crystal panel because the thickness is reduced compared to the conventional optical layered body in which the polarizing plate is bonded to the liquid crystal cell substrate via an adhesive. To be. Also, the adhesion between the polarizing plate and the liquid crystal cell substrate is good. Furthermore, since the composition that forms the adhesive layer contains an ultraviolet absorber, even when a polarizing plate that does not have ultraviolet absorbing ability is used, it depends on the active energy rays irradiated from the polarizing plate side of the optical laminate. The influence on the liquid crystal molecules in the liquid crystal cell can be suppressed. This optical laminated body can be particularly suitably applied to a large-sized liquid crystal display device such as a television. Further, according to the method of the present invention, such an optical laminate can be advantageously produced without affecting the liquid crystal molecules in the liquid crystal cell.

It is a cross-sectional schematic diagram which shows the basic layer structure of the optical laminated body which concerns on this invention. It is a cross-sectional schematic diagram which shows one form of the layer structure of the optical laminated body which concerns on this invention. It is a cross-sectional view schematically showing a reference embodiment of a layer structure of an optical science laminate.

  In the optical layered body of the present invention, as shown in a schematic cross-sectional view in FIG. 1, the liquid crystal cell substrate 1 and the polarizing plate 5 having a polarizing film in which a dichroic dye is adsorbed and oriented on a polyvinyl alcohol resin are active. It is bonded through an adhesive layer 2 made of a cured product of the energy ray curable resin composition. In this way, the liquid crystal cell substrate 1 / adhesive layer 2 / polarizing plate 5 is laminated to form the optical laminate 10. Hereinafter, the optical layered body of the present invention and the manufacturing method thereof will be described in detail.

[Liquid crystal cell substrate]
The liquid crystal cell substrate 1 constitutes a liquid crystal cell by sandwiching liquid crystal with another substrate (not shown), and this liquid crystal cell is a core member of the liquid crystal display device. The liquid crystal cell substrate 1 can be composed of glass or a transparent plastic sheet. The glass can be various commonly known glass plates such as soda lime glass, low alkali borosilicate glass, and non-alkali aluminoborosilicate glass, but alkali-free glass is particularly preferably used for the liquid crystal cell. In addition, the transparent plastic sheet may be any known one as long as it is transparent and can be a liquid crystal cell substrate. Specific examples include transparent resins such as polycarbonate, polymethyl methacrylate, polyethylene terephthalate, and epoxy resin. The flexible substrate which consists of can be mentioned.

[Adhesive layer]
Said liquid crystal cell substrate 1 and the polarizing plate 5 which has a polarizing film are bonded through an active energy ray curable resin composition. The active energy ray-curable resin composition contains an active energy ray-curable compound, that is, a compound that can be cured by irradiation with active energy rays as an active ingredient. As at least one of the compounds, an epoxy compound having at least one epoxy group in the molecule is employed. Here, the “epoxy compound having at least one epoxy group in the molecule” means a compound that has one or more epoxy groups in the molecule and can be cured by irradiation with active energy rays. In particular, the epoxy compound preferably has at least two epoxy groups in the molecule. In addition to the epoxy compound, the composition can also contain other active energy ray-curable compounds such as an oxetane compound and a (meth) acrylic compound described later.

  Such a curable resin composition is cured to form an adhesive layer 2 that joins the liquid crystal cell substrate 1 and the polarizing plate 5. This curing is usually performed by irradiation with active energy rays. By including an epoxy compound in the active energy ray-curable resin composition, it provides good adhesion between the liquid crystal cell substrate 1 and the polarizing plate 5, and also provides transparency, mechanical strength, thermal stability, and the like. An excellent adhesive layer with high durability can be formed.

<Epoxy compound>
The epoxy compound constituting the curable resin composition is preferably composed mainly of an epoxy compound that does not contain an aromatic ring in the molecule from the viewpoints of weather resistance, refractive index, cationic polymerization, and the like. Examples of the epoxy compound that does not contain an aromatic ring in the molecule include a glycidyl ether of a polyol having an alicyclic ring, an aliphatic epoxy compound, and an alicyclic epoxy compound. Such a preferable epoxy compound to be blended in the curable resin composition is described in detail in the above-mentioned Patent Document 1 (Patent No. 4306269) and Patent Document 2 (Patent No. 4306270). However, the outline will be explained here as well.

  The glycidyl ether of a polyol having an alicyclic ring is a compound obtained by glycidyl etherifying a hydroxyl group of a compound having at least two hydroxyl groups bonded to the alicyclic ring in the molecule. A polyol having an alicyclic ring, that is, a compound having at least two hydroxyl groups bonded to the alicyclic ring in the molecule is selectively hydrogenated to the aromatic ring under pressure in the presence of a catalyst. It can be obtained by performing. Examples of the aromatic polyol include bisphenol type compounds such as bisphenol A, bispheel F and bisphenol S; novolak type resins such as phenol novolac resin, cresol novolac resin and hydroxybenzaldehyde phenol novolac resin; tetrahydroxydiphenylmethane, tetra Examples thereof include polyfunctional compounds such as hydroxybenzophenone and polyvinylphenol. Glycidyl ether can be obtained by reacting an alicyclic polyol obtained by hydrogenating the aromatic ring of these aromatic polyols with epichlorohydrin. Among the glycidyl ethers of polyols having such alicyclic rings, hydrogenated bisphenol A diglycidyl ether is preferred.

  The aliphatic epoxy-based compound can be an aliphatic polyhydric alcohol or a polyglycidyl ether of an alkylene oxide adduct thereof. Specifically, 1,4-butanediol diglycidyl ether; 1,6-hexanediol diglycidyl ether; glycerin triglycidyl ether; trimethylolpropane triglycidyl ether; polyethylene glycol diglycidyl ether; propylene glycol And diglycidyl ethers of polyether polyols obtained by adding alkylene oxide (ethylene oxide or propylene oxide) to aliphatic polyhydric alcohols such as ethylene glycol, propylene glycol or glycerin.

  An alicyclic epoxy compound is a compound having at least one epoxy group bonded to an alicyclic ring in the molecule. Here, the “epoxy group bonded to the alicyclic ring” means a bridging oxygen atom “—O—” in the following formula, wherein m is an integer of 2 to 5.

A compound in which one or more hydrogen atoms in (CH ₂ ) _m in this formula are removed and bonded to another chemical structure can be an alicyclic epoxy compound. One or more hydrogen atoms in (CH ₂ ) _m forming the alicyclic ring may be appropriately substituted with a linear alkyl group such as a methyl group or an ethyl group.

  Among the epoxy compounds as described above, an alicyclic epoxy compound, that is, a compound in which at least one of the epoxy groups is bonded to the alicyclic ring is preferable, and in particular, an oxabicyclohexane ring (in the above formula) m = 3) and epoxy compounds having an oxabicycloheptane ring (m = 4 in the above formula) have a high elastic modulus of the cured product and good adhesion between the polarizing plate and the liquid crystal cell substrate. From the viewpoint of imparting sex, it is more preferably used.

  Specific examples of the alicyclic epoxy compound preferably used in the present invention are listed below. Here, the compound names are given first, and then the chemical formulas corresponding to each are shown, and the same reference numerals are given to the compound names and the chemical formulas corresponding thereto.

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-epoxycyclohexyl methyl ether),
G: ethylene glycol bis (3,4-epoxycyclohexyl methyl ether),
H: 2,3,14,15-diepoxy-7,11,18,21-tetraoxatrispiro [5.2.2.5.2.2] henicosane,
I: 3- (3,4-epoxycyclohexyl) -8,9-epoxy-1,5-dioxaspiro [5.5] undecane,
J: 4-vinylcyclohexene dioxide,
K: Limonene dioxide
L: bis (2,3-epoxycyclopentyl) ether,
M: Dicyclopentadiene dioxide and the like.

  In the present invention, the epoxy compound may be used alone or in combination of two or more.

<Cationically polymerizable compound that can be arbitrarily blended>
The active energy ray-curable resin composition used in the present invention can contain an oxetane compound in addition to the epoxy compound. By adding an oxetane compound, the viscosity of the active energy ray-curable resin composition can be lowered and the curing rate can be increased.

  An oxetane compound is a compound having at least one oxetane ring (four-membered ether) in the molecule, such as 3-ethyl-3-hydroxymethyloxetane, 1,4-bis [(3-ethyl-3 -Oxetanyl) methoxymethyl] benzene, 3-ethyl-3- (phenoxymethyl) oxetane, bis [(3-ethyl-3-oxetanyl) methyl] ether, 3-ethyl-3- (2-ethylhexyloxymethyl) oxetane, Phenol novolac oxetane etc. are mentioned. These oxetane-based compounds can be easily obtained from commercial products. For example, “Aron Oxetane OXT-101” and “Aron Oxetane OXT-” are trade names sold by Toagosei Co., Ltd. 121 ”,“ Aron Oxetane OXT-211 ”,“ Aron Oxetane OXT-221 ”,“ Aron Oxetane OXT-212 ”, and the like. Although the compounding quantity of an oxetane type compound is not specifically limited, It is 50 weight% or less normally based on the whole active energy ray-curable compound contained in an active energy ray-curable resin composition, Preferably it is 10-40 weight%.

<Photocationic polymerization initiator>
When the active energy ray-curable resin composition used for forming the adhesive layer contains a cationic polymerizable compound such as an epoxy compound or an oxetane compound, the curable resin composition usually contains a photocationic polymerization initiator. Blended. When a photocationic polymerization initiator is used, it becomes possible to form an adhesive layer at room temperature, so the need to consider the heat resistance of the polarizing film and distortion due to expansion is reduced, and the liquid crystal cell substrate 1 and the polarizing plate have good adhesion. 5 can be pasted. Moreover, since a photocationic polymerization initiator acts catalytically with light, even if it is mixed with a curable resin composition, the curable resin composition is excellent in storage stability and workability.

  The cationic photopolymerization initiator generates a cationic species or a Lewis acid by irradiation with active energy rays such as visible light, ultraviolet rays, X-rays, or electron beams, and includes cationic polymerization properties including epoxy compounds and oxetane compounds. Initiates a polymerization reaction of the compound. In the present invention, any type of photocationic polymerization initiator may be used. Specific examples include aromatic diazonium salts; onium salts such as aromatic iodonium salts and aromatic sulfonium salts; iron-allene complexes. and so on.

Examples of the aromatic diazonium salt include the following compounds.
Benzenediazonium hexafluoroantimonate,
Benzenediazonium hexafluorophosphate,
Benzenediazonium hexafluoroborate, etc.

Examples of the aromatic iodonium salt include the following compounds.
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 compounds.
Triphenylsulfonium hexafluorophosphate,
Triphenylsulfonium hexafluoroantimonate,
Triphenylsulfonium tetrakis (pentafluorophenyl) borate,
4,4'-bis (diphenylsulfonio) diphenyl sulfide bishexafluorophosphate,
4,4′-bis [bis (β-hydroxyethoxyphenyl) sulfonio] diphenyl sulfide bishexafluoroantimonate,
4,4′-bis [bis (β-hydroxyethoxyphenyl) sulfonio] diphenyl sulfide bishexafluorophosphate,
7- [bis (p-toluyl) sulfonio] -2-isopropylthioxanthone hexafluoroantimonate,
7- [bis (p-toluyl) sulfonio] -2-isopropylthioxanthone tetrakis (pentafluorophenyl) borate,
4-phenylcarbonyl-4'-diphenylsulfonio-diphenyl sulfide hexafluorophosphate,
4- (p-tert-butylphenylcarbonyl) -4'-diphenylsulfonio-diphenyl sulfide hexafluoroantimonate,
4- (p-tert-butylphenylcarbonyl) -4'-bis (p-toluyl) sulfonio-diphenyl sulfide tetrakis (pentafluorophenyl) borate and the like.

Moreover, as an iron-allene complex, the following compounds can be mentioned, for example.
Xylene-cyclopentadienyl iron (II) hexafluoroantimonate,
Cumene-cyclopentadienyl iron (II) hexafluorophosphate,
Xylene-cyclopentadienyl iron (II) tris (trifluoromethylsulfonyl) methanide.

These photocationic polymerization initiators can be easily obtained from commercial products. For example, “UVACURE 1590” and “ADEKA” sold by Daicel-Cytec, Inc. "Adekaoptomer SP-150" and "Adekaoptomer SP-170" sold by Nippon Kayaku Co., Ltd. "Kayarad PCI-220" and "Kayarad PCI-620" from Union Carbide "UVI-6990" being sold, "CI-5102", "CIT-1370", "CIT-1682", "CIP-1866S", "CIP-2048S" sold by Nippon Soda Co., Ltd. “CIP-2064S”, “DPI-101”, “DPI-102”, “DPI-103”, “DPI-105”, “MPI-103”, “MPI-105” sold by Midori Chemical Co., Ltd. ”,“ 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”, “PI-2074” sold by Rhodia, and the like.

  These photocationic polymerization initiators may be used alone or in combination of two or more. Among these, in particular, the aromatic sulfonium salt has an absorption characteristic even in a wavelength region near 300 nm, and thus has excellent curability and good mechanical strength, and is excellent for a liquid crystal cell substrate and a polarizing plate. Since it can give the hardened | cured material which has adhesiveness, it is used preferably.

  The compounding quantity of a photocationic polymerization initiator is 0.5-20 weight part normally with respect to a total of 100 weight part of the cationic polymerizable compound containing an epoxy-type compound and an oxetane type compound, Preferably it is 1-6 weight. Part. When the amount of the cationic photopolymerization initiator is small, curing becomes insufficient, and the mechanical strength and the adhesion between the liquid crystal cell substrate and the polarizing plate tend to be lowered. On the other hand, when the blending amount is too large, the ionic substance in the cured product increases, so that the hygroscopic property of the cured product is increased, and the durability performance of the obtained optical laminate may be reduced.

<Ultraviolet absorber>
In the present invention, an ultraviolet ray absorbent is contained in the active energy ray-curable resin composition containing at least the epoxy compound described above as the active energy ray-curable compound. Liquid crystal by active energy rays irradiated to cure the curable resin composition by blending an ultraviolet absorber with the curable resin composition and imparting ultraviolet absorbing ability to the layer formed from the composition. The influence on the cell can be suppressed. The ultraviolet absorber may be a compound having an absorption ability in an ultraviolet region having a wavelength of 400 nm or less, particularly 380 nm or less. For example, a benzotriazole ultraviolet absorber, a benzoate ultraviolet absorber, a 2-hydroxybenzophenone ultraviolet absorber, There are hydroxyphenyl triazine ultraviolet absorbers and the like. Among these, benzotriazole-based ultraviolet absorbers are representative and are also preferably used in the present invention.

Specific examples of the benzotriazole ultraviolet absorber include the following compounds.
2,2'-methylenebis [4- (1,1,3,3-tetramethylbutyl) -6- (2H-benzotriazol-2-yl) phenol],
2- (2-hydroxy-5-methylphenyl) -2H-benzotriazole,
2- (2-hydroxy-5-tert-butylphenyl) -2H-benzotriazole,
2- [2-hydroxy-3,5-bis (α, α-dimethylbenzyl) phenyl] -2H-benzotriazole,
2- [2-hydroxy-3- (α, α-dimethylbenzyl) -5-tert-octylphenyl] -2H-benzotriazole,
2- (3,5-di-tert-butyl-2-hydroxyphenyl) -2H-benzotriazole,
2- (3-tert-butyl-2-hydroxy-5-methylphenyl) -5-chloro-2H-benzotriazole,
2- (3,5-di-tert-butyl-2-hydroxyphenyl) -5-chloro-2H-benzotriazole,
2- (3,5-di-tert-amyl-2-hydroxyphenyl) -2H-benzotriazole,
2- (2-hydroxy-5-tert-octylphenyl) -2H-benzotriazole,
2- (3-dodecyl-2-hydroxy-5-methylphenyl) benzotriazole,
C ₇ -C ₉ alkyl esters of 3- [3- (2H-benzotriazol-2-yl) -5-tert-butyl-4-hydroxyphenyl] propionic acid,
Such as 3- [3- (5-chloro -2H- benzotriazol-2-yl) -5-tert-butyl-4-hydroxyphenyl] C ₇ -C ₉ alkyl esters of propionic acid.

  Specific examples of the benzoate ultraviolet absorber include 2,4-di-tert-butylphenyl 3,4-di-tert-butyl-4-hydroxybenzoate.

  Specific examples of 2-hydroxybenzophenone-based ultraviolet absorbers include 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-octyloxybenzophenone, 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxy-4 There are '-chlorobenzophenone, 2,2'-dihydroxy-4-methoxybenzophenone, 2,2'-dihydroxy-4,4'-dimethoxybenzophenone and the like.

  Hydroxyphenyltriazine-based UV absorbers have a phenyl group having a hydroxyl group bonded to one or two of 2-position, 4-position and 6-position of 1,3,5-triazine, and the remaining sites It is a compound in which a phenyl group having no hydroxyl group is bonded. Specifically, for example, 2,4-bis (2,4-dimethylphenyl) -6- [2-hydroxy-4- {3- (2-ethylhexyloxy) -2-hydroxypropoxy}] phenyl-1,3 , 5-triazine, 2,4-bis (4-butoxy-2-hydroxyphenyl) -6- (2,4-dibutoxyphenyl) -1,3,5-triazine, 2,4-diphenyl-6- ( 4-hexyloxy-2-hydroxyphenyl) -1,3,5-triazine and the like correspond to this.

  Various kinds of UV absorbers are sold by additive manufacturers, and BASF Japan Ltd. [former Ciba Japan Ltd.] is famous in Japan. Below, specific examples of UV absorbers sold by the company are listed by product name for each type of compound described above.

TINUVIN P, “TINUVIN PS”, “TINUVIN 99-2”, “TINUVIN 109,“ TINUVIN 213 ”,“ TINUVIN 234 ”,“ TINUVIN ”
326 ”,“ TINUVIN 328 ”,“ TINUVIN 329 ”,“ TINUVIN 384-2 ”,“ TINUVIN 571 ”,
"TINUVIN 900", "TINUVIN 928", "TINUVIN 1130" etc. are on sale.
“TINUVIN 120” is sold by the company as a benzoate UV absorber.
The company sells “CHIMASSORB 81” as a 2-hydroxybenzophenone UV absorber.
“TINUVIN 400” from the company as a hydroxyphenyltriazine UV absorber,
"TINUVIN 405", "TINUVIN 460", "TINUVIN 479", "TINUVIN 1577 FF" etc. are on sale.

  Some of the products of BASF Japan Ltd. shown here are a mixture of two or more types of compounds. The ultraviolet absorbers can be appropriately selected from known ones including those exemplified here, and of course, two or more types may be used in combination.

  The compounding quantity of a ultraviolet absorber shall be 0.1-20 weight part per 100 weight part of solid content of an active energy ray curable resin composition. Preferably, it is 5 to 20 parts by weight per 100 parts by weight of the solid content of the active energy ray-curable resin composition. Here, the “solid content of the active energy ray-curable resin composition” is a component constituting the curable composition and may react in the subsequent curing treatment, but the cured adhesive Means what remains in the layer. For example, when the curable resin composition contains a solvent, the solvent does not remain in the adhesive layer and therefore does not constitute a solid content. When the blending amount of the ultraviolet absorber exceeds 20 parts by weight per 100 parts by weight of the solid content of the active energy ray-curable resin composition, the curability of the curable resin composition is lowered and the durability of the resulting adhesive layer is reduced. Or the UV absorber bleeds from the adhesive layer. On the other hand, when the blending amount is less than 0.1 part by weight per 100 parts by weight of the solid content of the active energy ray curable resin composition, the ultraviolet absorbing ability is not sufficiently exhibited, and the curable resin composition layer is cured. There is a possibility that the active energy rays irradiated onto the liquid crystal will reach the liquid crystal cell beyond the layer and adversely affect the liquid crystal molecules therein.

<Radically polymerizable compounds that can be blended arbitrarily>
The active energy ray-curable resin composition used for forming the adhesive layer 2 contains a radically polymerizable (meth) acrylic compound together with the epoxy compound or together with the epoxy compound and the oxetane compound. Also good. By using a (meth) acrylic compound in combination, it can be expected to increase the hardness and mechanical strength of the adhesive layer, and more easily adjust the viscosity and curing speed of the active energy ray-curable resin composition. To be able to do that.

  The term “(meth) acrylic compound” as used herein means that either an acrylic acid ester or a methacrylic acid ester may be used. In this specification, (meth) acryloyl, (meth) acrylate, (meth) acrylic acid, etc. “(Meta)” in this case has the same purpose. The (meth) acrylic compound is obtained by reacting two or more kinds of a (meth) acrylate monomer having at least one (meth) acryloyloxy group in the molecule and a compound having a functional group. Examples include (meth) acrylate oligomers having at least two acryloyloxy groups. These monomers and oligomers will be specifically described below, but these monomers can be used alone or in combination of two or more as desired. The combination of two or more types includes a combination of monomers and a combination of oligomers, as well as a combination of one or more monomers and one or more oligomers. .

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

Specific examples of the monofunctional (meth) acrylate monomer include the following compounds.
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-dimethylaminoethyl (meth) acrylate,
Ethyl carbitol (meth) acrylate,
Trimethylolpropane mono (meth) acrylate,
Pentaerythritol mono (meth) acrylate,
Phenoxy polyethylene glycol (meth) acrylate etc.

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 include the following compounds.
2- (meth) acryloyloxyethyl phthalic acid,
2- (meth) acryloyloxyethyl hexahydrophthalic acid,
2-carboxyethyl (meth) acrylate,
2- (meth) acryloyloxyethyl succinic acid,
4- (meth) acryloyloxyethyl trimellitic acid and the like.

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

More specific examples of the bifunctional (meth) acrylate monomer include the following compounds.
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 hydroxypivalic acid 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,
Tricyclodecane dimethanol di (meth) acrylate,
1,3-dioxane-2,5-diyl di (meth) acrylate [alias: dioxane glycol di (meth) acrylate],
Di (meta) of acetal compound [chemical name: 2- (2-hydroxy-1,1-dimethylethyl) -5-ethyl-5-hydroxymethyl-1,3-dioxane] of hydroxypivalaldehyde and trimethylolpropane ) Acrylate,
1,3,5-tris (2-hydroxyethyl) isocyanurate di (meth) acrylate and the like.

There are various types of polyfunctional (meth) acrylate monomers having three or more functional groups. For example, poly (meth) acrylates of trivalent or higher aliphatic polyols are typical, and specific examples thereof are as follows. There are such compounds.
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 trivalent or higher-valent halogen-substituted polyols, tri (meth) acrylates of alkylene oxide adducts of glycerol, 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 can also be a polyfunctional (meth) acrylate monomer .

  On the other hand, (meth) acrylate oligomers include urethane (meth) acrylate oligomers, polyester (meth) acrylate oligomers, and epoxy (meth) acrylate oligomers.

  The urethane (meth) acrylate oligomer refers to a compound having at least two (meth) acryloyloxy groups in the molecule and a urethane bond (—NHCOO—). Specifically, a urethanization reaction product of a hydroxyl group-containing (meth) acrylate monomer and a polyisocyanate each having one hydroxyl group and at least one (meth) acryloyloxy group in the molecule, or a polyol is a polyisocyanate. Urethane reaction product of a terminal isocyanato group-containing urethane compound obtained by reacting with a hydroxyl group-containing (meth) acrylate monomer each having one hydroxyl group and at least one (meth) acryloyloxy group in the molecule, etc. It can be.

Specific examples of the hydroxyl group-containing (meth) acrylate monomer used in the urethanization reaction include the following compounds.
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 and the like.

Specific examples of the polyisocyanate subjected to the urethanization reaction with such a hydroxyl group-containing (meth) acrylate monomer include the following compounds.
Hexamethylene diisocyanate,
Lysine diisocyanate,
Isophorone diisocyanate,
Dicyclohexylmethane diisocyanate,
Tolylene diisocyanate,
Xylylene diisocyanate,
Compounds obtained by hydrogenating aromatic diisocyanates, such as hydrogenated tolylene diisocyanate, hydrogenated xylylene diisocyanate,
Triphenylmethane triisocyanate,
Dibenzylbenzene triisocyanate,
Polyisocyanate obtained by diversifying diisocyanates among these.

  Moreover, as polyols for manufacturing a terminal isocyanate group containing urethane compound by reaction with polyisocyanate, polyester polyol, polyether polyol, etc. can be used besides aliphatic and alicyclic polyols. Specific examples of aliphatic and alicyclic polyols include 1,4-butanediol, 1,6-hexanediol, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, neopentyl glycol, trimethylolethane, trimethylol. Examples include methylolpropane, ditrimethylolpropane, pentaerythritol, dipentaerythritol, dimethylolheptane, dimethylolpropionic acid, dimethylolbutyric acid, glycerin, and hydrogenated bisphenol A.

  The polyester polyol is a compound obtained by subjecting the above-described polyols to a dehydration condensation reaction of a polybasic carboxylic acid or an anhydride thereof. Specific examples of the polybasic carboxylic acid and its anhydride are listed as “(anhydrous)” on what may be an anhydride, and (anhydrous) succinic acid, adipic acid, (anhydrous) maleic acid, There are (anhydrous) itaconic acid, (anhydrous) trimellitic acid, (anhydrous) pyromellitic acid, (anhydrous) phthalic acid, isophthalic acid, terephthalic acid, hexahydro (anhydrous) phthalic acid and the like.

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

  The polyester (meth) acrylate oligomer refers to a compound having at least two (meth) acryloyloxy groups in the molecule and an ester bond. Specifically, it can be obtained by dehydration condensation reaction of (meth) acrylic acid, polybasic carboxylic acid or anhydride thereof, and polyol. Specific examples of the polybasic carboxylic acid or anhydride thereof used in the dehydration condensation reaction are listed as “(anhydrous)” on what may be an anhydride, and (anhydrous) succinic acid, adipic acid, (Anhydrous) maleic acid, (anhydrous) itaconic acid, (anhydrous) trimellitic acid, (anhydrous) pyromellitic acid, hexahydro (anhydrous) phthalic acid, (anhydrous) phthalic acid, isophthalic acid, terephthalic acid and the like. 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, trimethylol. Examples include methylolpropane, ditrimethylolpropane, pentaerythritol, dipentaerythritol, dimethylolheptane, dimethylolpropionic acid, dimethylolbutyric acid, glycerin, and hydrogenated bisphenol A.

  The epoxy (meth) acrylate oligomer means one obtained by addition reaction of polyglycidyl ether and (meth) acrylic acid, and also 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. and so on.

  When the (meth) acrylic compound is added to the active energy ray-curable resin composition used for forming the adhesive layer 2, the amount is 20% by weight or less based on the total amount of the active energy ray-curable compound. Furthermore, it is preferable to set it to 10 weight% or less. When the amount of the (meth) acrylic compound is increased, the adhesion between the liquid crystal cell substrate 1 and the polarizing plate 5 tends to be reduced.

<Photoradical polymerization initiator>
When the active energy ray-curable resin composition contains a radical polymerizable compound such as the (meth) acrylic compound described above, it is preferable to add a radical photopolymerization initiator. The radical photopolymerization initiator is not particularly limited as long as it can initiate the polymerization of the radical polymerizable compound by irradiation with active energy rays, and a conventionally known one can be used. Specific examples of the photoradical polymerization initiator include acetophenone, 3-methylacetophenone, benzyldimethyl ketal, 1- (4-isopropylphenyl) -2-hydroxy-2-methylpropan-1-one, 2-methyl-1 Acetophenone based initiators such as [4- (methylthio) phenyl-2-morpholinopropan-1-one and 2-hydroxy-2-methyl-1-phenylpropan-1-one; benzophenone, 4-chlorobenzophenone and 4 Benzophenone initiators such as 4,4'-diaminobenzophenone; benzoin ether initiators such as benzoin propyl ether and benzoin ethyl ether; thioxanthone initiators such as 4-isopropylthioxanthone; others, xanthone, fluorenone, camphor Down, benzaldehyde, there is such as anthraquinone.

  The compounding quantity of radical photopolymerization initiator is 0.5-20 weight part normally with respect to 100 weight part of radically polymerizable compounds, such as a (meth) acrylic-type compound, Preferably it is 1-6 weight part. When the radical polymerizable compound is present and the amount of the photo radical polymerization initiator is small, the curing becomes insufficient and the mechanical strength and the adhesion between the liquid crystal cell substrate 1 and the polarizing plate 5 tend to decrease. . On the other hand, if the amount of the photo radical polymerization initiator is too large, the active energy ray-curable compound in the curable resin composition (a radical polymerizable compound such as a cationic polymerizable compound including an epoxy compound and a (meth) acrylic compound) is used. ) Is relatively small, and the durability of the resulting optical laminate may be reduced.

<Other optional components that can be incorporated into the curable resin composition>
The active energy ray-curable resin composition can further contain a photosensitizer as necessary. By adding a photosensitizer, the reactivity of cationic polymerization and / or radical polymerization can be improved, and the mechanical strength of the adhesive layer and the adhesion between the polarizing plate and the liquid crystal cell substrate can be improved. . The photosensitizer may be a compound having a maximum absorption at a wavelength longer than 380 nm. For example, a carbonyl compound, an organic sulfur compound, a persulfide, a redox compound, an azo and diazo compound, a halogen compound, an anthracene compound, light And reducing dyes. Examples of carbonyl compounds that can be photosensitizers include benzoin derivatives such as benzoin methyl ether, benzoin isopropyl ether and α, α-dimethoxy-α-phenylacetophenone; benzophenone, 2,4-dichlorobenzophenone, o-benzoyl Benzophenone compounds such as methyl benzoate, 4,4'-bis (dimethylamino) benzophenone and 4,4'-bis (diethylamino) benzophenone; thioxanthone derivatives such as 2-chlorothioxanthone and 2-isopropylthioxanthone; Anthraquinone derivatives such as chloroanthraquinone and 2-methylanthraquinone; and acridone derivatives such as N-methylacridone and N-butylacridone. Anthracene compounds preferably have alkoxy groups at the 9- and 10-positions of anthracene. Examples of anthracene compounds that can be used as photosensitizers include 9,10-dipropoxyanthracene, 9,10- Examples include dibutoxyanthracene, 2-methyl- or 2-ethyl-9,10-dipropoxyanthracene, 2-methyl- or 2-ethyl-9,10-dibutoxyanthracene. These photosensitizers may be used alone or in combination of two or more. When mix | blending a photosensitizer, the quantity is about 0.1-20 weight part normally by making the whole active energy ray-curable compound into 100 weight part.

  Moreover, the active energy ray-curable resin composition may contain an antistatic agent for imparting antistatic performance to the optical laminate. The antistatic agent is not particularly limited, and various known antistatic agents can be used. For example, a cationic surfactant, an anionic surfactant, a nonionic surfactant, an ionic compound having an organic cation other than the cationic surfactant, an ionic compound having an organic anion other than the anionic surfactant, and conductivity Inorganic particles, conductive polymers, and the like can be used. The blending ratio of these antistatic agents is appropriately determined according to the desired characteristics, but is usually about 0.1 to 10 parts by weight with 100 parts by weight of the entire active energy ray-curable compound.

  The active energy ray-curable resin composition can be blended with known additives usually used for polymer materials. For example, primary antioxidants such as phenols and amines, sulfur secondary antioxidants and the like can be mentioned.

  A leveling agent can also be mix | blended with an active energy ray curable resin composition. In applying this curable resin composition onto the polarizing plate, if the wettability to the polarizing plate is poor, the wettability can be improved by blending a leveling agent. The leveling agent can be various compounds having a leveling effect, such as silicone-based, fluorine-based, polyether-based, acrylic acid copolymer-based, and titanate-based. When a leveling agent is blended, the amount is about 0.01 to 1 part by weight with respect to 100 parts by weight of the active energy ray-curable compound contained in the curable resin composition.

  Furthermore, the active energy ray-curable resin composition may contain a solvent as necessary. The solvent is appropriately selected in consideration of the solubility of the components constituting the curable resin composition. Commonly used solvents include 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, Ketones such as methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone; esters such as methyl acetate, ethyl acetate and butyl acetate; cellosolves such as methyl cellosolve, ethyl cellosolve and butyl cellosolve; halogenated carbonization such as methylene chloride and chloroform Hydrogen etc. are mentioned. The mixing ratio of the solvent is appropriately determined from the viewpoint of adjusting the viscosity depending on the processing purpose such as film formability.

<Adhesive layer thickness>
The thickness of the adhesive layer 2 is preferably 10 μm or less from the viewpoint of reducing the thickness and weight of the optical laminate, and more preferably 5 μm or less. When the thickness of the adhesive layer is 10 μm or less, there is little risk of impairing the appearance of the polarizing plate. On the other hand, if the thickness exceeds 10 μm, the adhesive force between the liquid crystal cell substrate and the polarizing plate may not be sufficient due to insufficient curing of the adhesive.

<Transmittance of adhesive layer>
In the adhesive layer 2, the active energy rays irradiated from the polarizing plate 5 side are mostly absorbed and consumed by the adhesive layer, and adversely affect liquid crystal molecules on the opposite side of the liquid crystal cell substrate 1 from the polarizing plate 5. From the viewpoint of avoiding this, it is preferable that the transmittance with respect to light having a wavelength of 380 nm is 30% or less, more preferably 20% or less, and particularly preferably 10% or less. If the transmittance with respect to light of 380 nm is larger than 30%, the ultraviolet ray absorbing ability is not sufficient, and the possibility of adversely affecting the liquid crystal molecules in the liquid crystal cell increases. On the other hand, since the optical layered body of the present invention is used in a liquid crystal display device, the transmittance in the visible light region is preferably high. Therefore, the adhesive layer 2 preferably has a transmittance for light having a wavelength of 500 nm of 75% or more, and more preferably 80% or more.

[Polarizer]
As described above with reference to FIG. 1, the optical layered body of the present invention includes a polarizing plate 5 bonded to the liquid crystal cell substrate 1 via the adhesive layer 2 described above. The polarizing plate 5 has at least a polarizing film in which a dichroic dye is adsorbed and oriented on a polyvinyl alcohol resin. Polarizer 5, the optical laminate 10, from the viewpoint of further thinning the liquid crystal panel, you composed to have a film thickness of not more than 1 00μm. Brittle in the polarizing film alone Keru set the transparent protective layer on a surface opposite to the surface to be stuck to the liquid crystal cell substrate 1.

  FIG. 2 is a schematic cross-sectional view showing one embodiment of the layer configuration of the optical laminate according to the present invention. In this embodiment, a transparent protective layer 7 is provided on one surface of the polarizing film 6 to form a polarizing plate 5, and the surface of the polarizing film 6 opposite to the surface on which the transparent protective layer 7 is provided directly through the adhesive layer 2. The optical laminate 11 is configured by being bonded to the liquid crystal cell substrate 1.

Figure 3 is a cross-sectional view schematically showing a reference embodiment of a layer structure of an optical science laminate. In this embodiment, the transparent protective layer 7 is provided on one side of the polarizing film 6, and an appropriate resin layer 8 is provided on the other side of the polarizing film 6 to form the polarizing plate 5, and the resin layer 8 side is interposed through the adhesive layer 2. The optical laminate 12 is configured by being bonded to the liquid crystal cell substrate 1. The resin layer 8 can be a transparent protective layer similar to or different from the transparent protective layer 7 provided on the opposite side of the polarizing film 6, and may be an optical functional layer. As an example of the optical function layer, there is a retardation plate used for the purpose of compensating for a retardation by a liquid crystal cell. Examples of retardation plates include birefringent films made of stretched plastic films, films in which discotic liquid crystals and nematic liquid crystals are oriented and fixed, and retardation development of the above liquid crystals and inorganic layered compounds on a film substrate. For example, a coating film containing a substance is formed and the orientation is fixed. In this case, a cellulose-based film such as triacetyl cellulose is preferably used as a film substrate that supports a coating film containing a retardation-expressing substance.

Polarizing plate 5, Rukoto configure a polarizing film 6 including two layers it is preferable from the viewpoint of thinning the optical laminate or a liquid crystal panel while protecting the polarizing film 6. Such viewpoint et al, as shown in FIG. 2, a transparent protective layer 7 on one side of the polarizing film 6, directly in the polarizing film surface made from the opposite side of the polyvinyl alcohol-based resin and its transparent protective layer 7 , the form as it is laminated to the liquid crystal cell substrate 1 via an adhesive layer 2, the present invention is Ru is employed.

<Polarized film>
The polarizing film 6 constituting the polarizing plate 5 is obtained by adsorbing and orienting a dichroic dye on a polyvinyl alcohol resin. More specifically, a film obtained by adsorbing and orienting a dichroic dye on a uniaxially stretched polyvinyl alcohol resin film is preferably used.

  The polyvinyl alcohol resin constituting the polarizing film can be obtained by saponifying a polyvinyl acetate resin. Examples of the polyvinyl acetate resin include polyvinyl acetate, which is a homopolymer of vinyl acetate, and copolymers of vinyl acetate and other monomers copolymerizable therewith. Examples of other monomers copolymerizable with vinyl acetate include unsaturated carboxylic acids, unsaturated sulfonic acids, olefins, and vinyl ethers. The saponification degree of the polyvinyl alcohol-based resin is usually about 85 to 100 mol%, preferably 98 to 100 mol%. The polyvinyl alcohol resin may be further modified. For example, polyvinyl formal or polyvinyl acetal modified with aldehydes may be used. The degree of polymerization of the polyvinyl alcohol resin is usually about 1,000 to 10,000, preferably about 1,500 to 10,000.

  A film obtained by forming such a polyvinyl alcohol resin is used as a raw film of a polarizing film. The method for forming a polyvinyl alcohol-based resin is not particularly limited, and can be formed by a known method. Although the film thickness of a polyvinyl alcohol-type raw film is not specifically limited, For example, it is about 10-150 micrometers.

  A polarizing film is usually a process of uniaxially stretching a raw film made of a polyvinyl alcohol resin as described above, a process of dyeing a polyvinyl alcohol resin film with a dichroic dye and adsorbing the dichroic dye, two colors It is manufactured through a step of treating a polyvinyl alcohol-based resin film adsorbed with a functional dye with an aqueous boric acid solution and a step of washing with water after the treatment with the aqueous boric acid solution.

  Uniaxial stretching may be performed before dyeing with a dichroic dye, may be performed simultaneously with dyeing, or may be performed after dyeing. When uniaxial stretching is performed after dyeing with a dichroic dye, the uniaxial stretching may be performed before boric acid treatment or during boric acid treatment. Moreover, it is also possible to perform uniaxial stretching in these several steps. In uniaxial stretching, it may be uniaxially stretched between rolls having different peripheral speeds, or may be uniaxially stretched using a hot roll. Further, it may be dry stretching such as stretching in the air, or may be wet stretching in which stretching is performed in a state swollen with a solvent. The draw ratio is usually about 4 to 8 times.

  For example, the polyvinyl alcohol resin film is dyed with a dichroic dye by immersing the polyvinyl alcohol resin film in an aqueous solution containing the dichroic dye. As the dichroic dye, iodine, a dichroic organic dye, or the like is used. Moreover, it is preferable that the polyvinyl alcohol-type resin film is immersed in water before the dyeing process.

  For dyeing when iodine is used as the dichroic dye, a method of immersing a polyvinyl alcohol-based resin film in an aqueous solution containing iodine and potassium iodide is usually employed. The content of iodine in this aqueous solution is usually about 0.01 to 0.5 parts by weight with respect to 100 parts by weight of water, and the content of potassium iodide is usually 0.00 with respect to 100 parts by weight of water. About 5 to 10 parts by weight. The temperature of the aqueous solution used for dyeing is usually about 20 to 40 ° C., and the immersion time (dyeing time) in this aqueous solution is usually about 30 to 300 seconds.

On the other hand, for dyeing when a dichroic organic dye is used as the dichroic dye, a method of immersing a polyvinyl alcohol-based resin film in an aqueous dye solution containing a water-soluble dichroic dye is usually employed. The content of the dichroic dye in this aqueous dye solution is usually about 1 × 10 ⁻³ to 1 × 10 ⁻² parts by weight with respect to 100 parts by weight of water. The dye aqueous solution may contain an inorganic salt such as sodium sulfate as a dyeing assistant. The temperature of the aqueous dye solution is usually about 20 to 80 ° C., and the immersion time (dyeing time) in the aqueous dye solution is usually about 30 to 300 seconds.

  The boric acid treatment after dyeing with the dichroic dye is performed by immersing the dyed polyvinyl alcohol-based resin film in a boric acid-containing aqueous solution. The boric acid content in the boric acid-containing aqueous solution is usually about 2 to 15 parts by weight, preferably about 5 to 12 parts by weight with respect to 100 parts by weight of water. When iodine is used as the dichroic dye, the boric acid-containing aqueous solution preferably contains potassium iodide. The content of potassium iodide in the boric acid-containing aqueous solution is usually about 2 to 20 parts by weight, preferably about 5 to 15 parts by weight with respect to 100 parts by weight of water. The immersion time in the boric acid-containing aqueous solution is usually about 100 to 1,200 seconds, preferably about 150 to 600 seconds, and more preferably about 200 to 400 seconds. The temperature of the boric acid-containing aqueous solution is usually 50 ° C or higher, preferably 50 to 85 ° C.

  The polyvinyl alcohol resin film after the boric acid treatment is usually washed with water. The water washing treatment is performed, for example, by immersing a boric acid-treated polyvinyl alcohol resin film in water. The temperature of water in the water washing treatment is usually about 5 to 40 ° C., and the immersion time is about 2 to 120 seconds. After washing with water, a drying process is performed to obtain a polarizing film. The drying process can be performed using a hot air dryer or a far infrared heater. A drying temperature is about 40-100 degreeC normally. The time for the drying treatment is usually about 120 to 600 seconds.

  As described above, a polarizing film in which a dichroic dye is adsorbed and oriented on a uniaxially stretched polyvinyl alcohol resin film can be produced. The thickness of the polarizing film can be about 5 to 40 μm.

<Transparent protective layer and resin layer>
Resin layer 8 eclipsed set on the opposite side in the reference embodiment shown in transparent protective layer 7 provided on one side, and FIG. 3 of the polarizing film 6 is, for example, cellulose acetate resins, cycloolefin resins, polyolefin resins, acrylic It can be composed of an appropriate thermoplastic resin film that has been widely used as a material for forming a protective layer in the art, such as a resin, a polyimide resin, a polycarbonate resin, and a polyester resin. Moreover, the transparent protective layer 7 can also be comprised with the hardened | cured material of an active energy ray curable resin composition. From these viewpoints of mass productivity and adhesiveness, among these, a film made of a cellulose acetate-based resin, a cycloolefin-based resin, or a polyester-based resin, or a cured product of an active energy ray-curable resin composition is used as the transparent protective layer 7. It is preferable to do. When the transparent protective layer 7 and / or the resin layer 8 are composed of a thermoplastic resin film, the thickness is usually about 10 to 50 μm. On the other hand, when the transparent protective layer 7 is composed of a cured product of the active energy ray-curable resin composition, the thickness can be 10 μm or less, for example, about 1 to 10 μm.

  The cellulose acetate-based resin film used as the transparent protective layer 7 and / or the resin layer 8 is a film made of a cellulose part or a complete acetate ester, and examples thereof include a triacetyl cellulose film and a diacetyl cellulose film.

  As the cellulose acetate-based resin film, an appropriate commercial product can be used. Examples of commercially available products are “Fujitac TD80”, “Fujitac TD80UF” and “Fujitac TD80UZ” sold by Fuji Film Co., Ltd. “KC8UX2M” and “KC8UY” sold by Konica Minolta Opto Co., Ltd. Etc. (both are trade names).

  Further, the cycloolefin resin used as the transparent protective layer 7 and / or the resin layer 8 is a thermoplastic non-polymer having a monomer unit composed of a cyclic olefin (cycloolefin) such as norbornene or a polycyclic norbornene monomer. A crystalline resin (also called an amorphous polyolefin resin). The cycloolefin-based resin may be a hydrogenated product of the above-mentioned cycloolefin ring-opening polymer or a hydrogenated product of a ring-opening copolymer using two or more kinds of cycloolefins. It may be an addition copolymer with an olefin and / or an aromatic compound having a vinyl group. In addition, a polar group may be introduced.

  When a transparent protective layer is formed using a copolymer of a cycloolefin and a chain olefin and / or an aromatic compound having a vinyl group, examples of the chain olefin include ethylene, propylene, and the like. Examples of the aromatic compound include styrene, α-methylstyrene, and nuclear alkyl-substituted styrene. In such a copolymer, the unit of the monomer composed of cycloolefin may be 50 mol% or less (preferably 15 to 50 mol%). In particular, when a terpolymer of a cycloolefin, a chain olefin, and an aromatic compound having a vinyl group is used, the amount of the monomer unit comprising the cycloolefin can be made relatively small as described above. In such a terpolymer, the monomer unit composed of a chain olefin is usually 5 to 80 mol%, and the monomer unit composed of an aromatic compound having a vinyl group is usually 5 to 80 mol%.

  An appropriate commercially available product can be used as the cycloolefin resin. Examples of commercial products are “TOPAS” manufactured by TOPAS ADVANCED POLYMERS GmbH and sold in Japan by Polyplastics Co., Ltd., “Arton” sold by JSR Co., Ltd., and Nippon Zeon Co., Ltd. There are "ZEONOR" and "ZEONEX" sold by, and "Apel" sold by Mitsui Chemicals, Inc. (all are trade names). When such a cycloolefin-based resin is formed into a film, a known method such as a solvent casting method or a melt extrusion method is appropriately used. In addition, for example, "Essina" and "SCA40" sold by Sekisui Chemical Co., Ltd., "Arton Film" sold by JSR Corporation, and "Zeonor Film" sold by Nippon Zeon Corporation. (All are trade names), a film made of a cycloolefin resin formed in advance may be used as the transparent protective layer 7 and / or the resin layer 8.

  The cycloolefin resin film used for the resin layer 8 may be uniaxially stretched or biaxially stretched and provided with a phase difference. In this case, the draw ratio is usually 1.1 to 5 times, preferably 1.1 to 3 times.

  Furthermore, the polyester resin used as the transparent protective layer 7 and / or the resin layer 8 is typically polyethylene terephthalate. A polyester-based resin film having a polyethylene terephthalate film as a representative example is provided with strength and transparency by uniaxial stretching or biaxial stretching. A stretched film made of a polyester resin, particularly polyethylene terephthalate, is particularly suitable as the transparent protective layer 7 disposed on the side far from the liquid crystal cell substrate 1.

  On the other hand, when the transparent protective layer 7 is formed from the active energy ray-curable resin composition, the same material as described for the active energy ray-curable resin composition forming the adhesive layer 2 can be used. . The active energy ray-curable resin composition for forming the transparent protective layer and the active energy ray-curable resin composition for forming the adhesive may be the same or different.

  Specifically, the active energy ray-curable resin composition used for the transparent protective layer 7 contains an epoxy compound as in the active energy ray-curable resin composition used for forming the adhesive layer 2 described above. Are effective, and it is also effective to contain an oxetane compound. Thus, when it contains an epoxy compound and optionally further contains an oxetane compound, a photocationic polymerization initiator is also usually blended. About these epoxy compounds, oxetane compounds and photocationic polymerization initiators, the same explanation as described above for the adhesive layer 2 applies.

  In particular, the active energy ray-curable resin composition used for the transparent protective layer 7 includes a radically polymerizable compound, specifically, as described above (Metal) in addition to an epoxy compound and an optional oxetane compound. ) It is effective to contain an acrylic compound. By using a (meth) acrylic compound in combination, a transparent protective layer having high hardness, excellent mechanical strength, and superior durability can be obtained. Furthermore, adjustment of the viscosity and curing rate of the active energy ray-curable resin composition can be performed more easily. In the active energy ray-curable resin composition for the transparent protective layer 7, the (meth) acrylic compound can be added up to about 70% by weight based on the total amount of the active energy ray-curable compound. The blending amount of the (meth) acrylic compound is more preferably 35 to 70% by weight, especially 40 to 60% by weight. When the compounding amount of the (meth) acrylic compound exceeds 70% by weight, the adhesion with the polarizing film tends to be lowered.

  When blending such a (meth) acrylic compound, a radical photopolymerization initiator as described above is also blended. About the compounding quantity of radical photopolymerization initiator, the description similar to having described about the adhesive bond layer 2 applies previously. The active energy ray-curable resin composition used for the transparent protective layer 7 can also contain other various components similar to those described above for the adhesive layer 2.

  The transparent protective layer 7 of the polarizing plate has a surface opposite to the surface to be attached to the polarizing film and subjected to surface treatment such as antiglare treatment, hard coat treatment, antistatic treatment, and antireflection treatment. Also good. Moreover, the coating layer which consists of a liquid crystalline compound, its high molecular weight compound, etc. may be formed in the surface on the opposite side to the surface bonded to the polarizing film of the resin layer 8, and may become the phase difference plate mentioned above.

<Adhesion between polarizing film and transparent protective layer and / or resin layer>
When the transparent protective layer 7 is a resin film, and when the resin layer 8 is a film, an adhesive is used for adhering the polarizing film 6 and the transparent protective layer 7 and adhering the polarizing film 6 and the resin layer 8. Used. The adhesive used for this purpose is not particularly limited, and examples thereof include a curable resin composition containing an active energy ray-curable compound and a water-based adhesive in which an adhesive component is dissolved or dispersed in water. Among these, since a drying process is unnecessary, it is preferable to use a curable resin composition containing an active energy ray-curable compound. When the curable resin composition is used as an adhesive, the polarizing film 6 and the transparent protective layer 7, and optionally the polarizing film 6 and the resin layer 8 are interposed through the layer of the curable resin composition. After bonding, this bonding material is irradiated with an active energy ray to cure the curable resin composition layer.

  When the curable resin composition is used as an adhesive, the same materials as those described for the active energy ray-curable resin composition used for adhesion between the liquid crystal cell substrate 1 and the polarizing plate 5 described above can be used. . Curable resin composition used for adhesion between liquid crystal cell substrate 1 and polarizing plate 5, curable resin composition used for adhesion between polarizing film 6 and transparent protective layer 7, and adhesion between polarizing film 6 and resin layer 8. May be the same or different.

  On the other hand, examples of the water-based adhesive in which the adhesive component is dissolved or dispersed in water include a composition mainly composed of a polyvinyl alcohol resin or a urethane resin.

  When a polyvinyl alcohol resin is used as the main component of the water-based adhesive, the polyvinyl alcohol resin can be partially saponified polyvinyl alcohol or fully saponified polyvinyl alcohol, carboxyl group-modified polyvinyl alcohol, acetoacetyl group It may be a modified polyvinyl alcohol resin such as modified polyvinyl alcohol, methylol group-modified polyvinyl alcohol, amino group-modified polyvinyl alcohol. When a polyvinyl alcohol resin is used as an adhesive component, the adhesive is often prepared as an aqueous solution of a polyvinyl alcohol resin. The density | concentration of the polyvinyl alcohol-type resin in an adhesive agent is about 1-10 weight part normally with respect to 100 weight part of water, Preferably it is 1-5 weight part.

  In order to improve the adhesiveness, it is preferable to add a curable component such as glyoxal or a water-soluble epoxy resin or a crosslinking agent to the adhesive containing a polyvinyl alcohol resin as a main component. Examples of water-soluble epoxy resins include polyamide polyamines obtained by reacting a polyalkylene polyamine such as diethylenetriamine or triethylenetetramine with a polycarboxylic acid such as adipic acid and epichlorohydrin. An epoxy resin can be mentioned. Examples of such commercially available polyamide polyamine epoxy resins include “Smiles Resin 650” and “Smiles Resin 675” sold by Sumika Chemtex Co., Ltd., and those sold by Nippon PMC Co., Ltd. There is “WS-525”. The addition amount of these curable components or crosslinking agents is usually 1 to 100 parts by weight, preferably 1 to 50 parts by weight, with respect to 100 parts by weight of the polyvinyl alcohol resin. If the amount added is small, the effect of improving the adhesiveness is reduced, while if the amount added is large, the adhesive layer tends to be brittle.

  When a urethane resin is used as the main component of the water-based adhesive, an example of a suitable composition is a mixture of a polyester ionomer type urethane resin and a compound having a glycidyloxy group. The polyester-based ionomer type urethane resin here is a urethane resin having a polyester skeleton, into which a small amount of an ionic component (hydrophilic component) is introduced. Such an ionomer-type urethane resin is suitable as a water-based adhesive because it is emulsified directly in water without using an emulsifier to form an emulsion. It is publicly known to use a polyester ionomer type urethane resin as an adhesive for a polarizing plate. For example, in JP-A-2005-70140 and JP-A-2005-181817, a polarizing film comprising a polyvinyl alcohol-based resin is prepared by using a mixture of a polyester-based ionomer urethane resin and a compound having a glycidyloxy group as an adhesive. The form which joins a cycloolefin system resin film is shown.

[Method for producing optical laminate]
The optical laminate described above can be advantageously produced by a method comprising the following (1) curable resin composition layer forming step, (2) bonding step, and (3) curing step.

(1) The surface of the polarizing film 6 of the polarizing plate 5 having a polarizing film in which a dichroic dye is adsorbed and oriented on a polyvinyl alcohol-based resin contains an epoxy compound having at least one epoxy group in the molecule, Furthermore, a curable resin composition layer forming step for forming a layer of an active energy ray-curable resin composition containing 0.1 to 20 parts by weight of an ultraviolet absorber per 100 parts by weight of the solid content of the composition,
(2) A bonding step of bonding a layer of the curable resin composition formed on the surface of the polarizing plate 5 in the curable resin composition layer forming step to the liquid crystal cell substrate 1, and (3) the bonding described above. Irradiation of active energy rays such as visible light, ultraviolet rays, X-rays, or electron beams from the polarizing plate 5 side of the laminate comprising the liquid crystal cell substrate 1 / curable resin composition layer / polarizing plate 5 obtained in the process. And a curing step of curing the curable resin composition layer to form the adhesive layer 2.

In this manufacturing method, when forming the transparent protective layer which consists of hardened | cured material of an active energy ray curable resin composition in the single side | surface of the polarizing film 6 which comprises the polarizing plate 5 , or it consists of an active energy ray curable resin composition. When laminating a film via an adhesive, in the above curing step, simultaneously with curing of the curable resin composition layer to be the adhesive layer 2, curing of the transparent protective layer, or bonding the polarizing film and another film It is also possible to cure the adhesive. Hereinafter, each step will be specifically described.

  First, in the curable resin composition layer forming step (1), in order to form a layer of the active energy ray-curable resin composition on the surface of the polarizing plate 5, the polarizing plate 5 is bonded to the liquid crystal cell substrate 1. Apply the curable resin composition directly on the surface, and apply the curable resin composition to a base film made of a transparent resin prepared separately or as needed. A method of transferring the coating layer of the curable resin composition to the polarizing plate 5 after drying can be employed. When employ | adopting the latter method, a base film is removed after that and it uses for the following bonding process. As the base film, for example, a polyester resin film, a polycarbonate film, a triacetyl cellulose film, a norbornene resin film, a polystyrene film, and the like whose representative examples are polyethylene terephthalate films can be used. The surface on which the curable resin composition of the base film is coated may be subjected to a peeling treatment.

  As shown in FIG. 2, it is a case where the transparent protective layer 7 is provided in the surface on the opposite side to the liquid crystal cell substrate 1 side in the polarizing film 6, Comprising: The transparent protective layer 7 is comprised with the hardened | cured material of curable resin composition. In this case, a layer of the curable resin composition to be the transparent protective layer 7 is also provided on the surface of the polarizing film 6 to cure the layer to be the transparent protective layer 7 and the layer to be the adhesive layer 2. It is preferable to carry out the curing simultaneously. When the layer of the curable resin composition to be the transparent protective layer 7 is formed on another base film and bonded to the polarizing film 6, the base film remains as it is until the subsequent curing step, and the curing step After finishing, it is preferable to peel off.

  Thereafter, in the bonding step (2), the adhesive layer 2 provided on the polarizing plate 5 is bonded to the liquid crystal cell substrate 1. Next, in the curing step (3), visible light, ultraviolet rays, X-rays, or electron beams from the polarizing plate 5 side of the laminate laminated in the order of liquid crystal cell substrate 1 / curable resin composition layer / polarizing plate 5 are used. By irradiating such active energy rays, the curable resin composition layer is cured to form an adhesive layer 2 to obtain an optical laminate. At this time, when the curable resin composition layer for forming the transparent protective layer 7 is provided on the surface of the polarizing film 6 opposite to the liquid crystal cell substrate 1 side, the transparent protective layer 7 is used. The curable resin composition can be cured at the same time. When the base film is provided on the transparent protective layer 7, the base film is finally peeled off.

On the other hand, for example, in the case of using a polarizing plate 5 having a transparent protective layer 7 made of a resin film on one side of a polarizing film 6 as shown in FIG. 2, the polarizing film 6 and the transparent protective layer 7 are made of a curable resin. In the case of bonding with an adhesive made of the composition, a curable resin composition is applied to the bonding surface of the polarizing film 6 and / or the transparent protective layer 7, and the polarizing film 6 and the transparent protective layer are protected via the composition layer. After laminating the layer 7 , the others were the same as above, and after obtaining a laminated product laminated in the order of liquid crystal cell substrate 1 / curable resin composition layer / polarizing plate 5, What is necessary is just to irradiate an active energy ray by the same method.

  A curable resin composition layer for adhering the liquid crystal cell substrate 1 and the polarizing plate 5 is not formed on the surface of the polarizing plate 5 but spinned on the bonding surface of the liquid crystal cell substrate 1 with the polarizing plate. An optical laminate can also be produced by a method of coating by a coating method or the like, overlaying the polarizing plate 5 thereon, irradiating active energy rays from the polarizing plate 5 side, and curing the layer of the curable resin composition. . However, if the ease of production is also taken into consideration, after the layer of the curable resin composition described above is formed on one side of the polarizing plate 5 and the layer of the curable resin composition is bonded to the liquid crystal cell substrate 1, The method of curing the adhesive layer 2 is advantageous.

  The means for applying the active energy ray-curable resin composition for forming the adhesive layer or the transparent protective layer to the polarizing plate, the resin film or the base film is not particularly limited, and for example, a doctor blade, a wire Various coating methods such as bar, die coater, comma coater and gravure coater can be used. In addition, since each coating method has an optimum viscosity range, it is also a useful technique to adjust the viscosity using a solvent. As the solvent for this, the same solvent as described above can be used.

  The light source used for the irradiation of the active energy ray is not particularly limited, and has a light emission distribution at a wavelength of 400 nm or less, for example, a low pressure mercury lamp, a medium pressure mercury lamp, a high pressure mercury lamp, an ultrahigh pressure mercury lamp, a chemical lamp, a black light lamp, a microwave. An excited mercury lamp, a metal halide lamp, or the like can be used.

Although the light irradiation intensity to the curable resin composition varies from composition to composition, the irradiation intensity in the wavelength region effective for activation of the photocationic polymerization initiator and the photoradical polymerization initiator blended as necessary is 10 It is preferable to be ˜2,500 mW / cm ² . If the light irradiation intensity is low, the reaction time becomes too long, while if the intensity is too high, the heat radiated from the lamp and the heat generated during the polymerization of the active energy ray curable resin composition cause curable resin composition. May cause yellowing and deterioration of the polarizing film.

The light irradiation time to the curable resin composition is also controlled for each composition and is not particularly limited. However, the integrated light amount represented by the product of the irradiation intensity and the irradiation time is 10 to 2500 mJ / It is preferably set to be cm ² . If the integrated light quantity is small, the generation of the active species derived from the polymerization initiator is not sufficient, and the resulting adhesive layer may be insufficiently cured. On the other hand, if the amount of integrated light is increased, the irradiation time becomes very long, which is disadvantageous for productivity. In addition, it is preferable that irradiation of an active energy ray is performed in the range in which various performances, such as the polarization degree and transmittance | permeability of a polarizing film, do not fall.

[Liquid Crystal Display]
In the optical laminate of the present invention, another liquid crystal cell substrate is disposed on the opposite side of the surface of the liquid crystal cell substrate 1 to which the polarizing plate 5 is bonded, and the liquid crystal is sandwiched between the two. , A liquid crystal cell or a liquid crystal panel. A liquid crystal display device is configured using the liquid crystal cell or the liquid crystal panel as a display element. The liquid crystal cell itself in a state in which liquid crystal is sealed between two liquid crystal cell substrates is used as the liquid crystal cell substrate 1 in FIGS. 1 and 2, and a polarizing plate is bonded to one or both surfaces according to the present invention to form a liquid crystal panel. It can also be. Since the optical layered body of the present invention is excellent in durability against thermal shock tests and the like, the liquid crystal display device produced as described above is also excellent in durability against thermal shock tests and is thin. The weight will be reduced.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated further more concretely, this invention is not limited by these examples. In the examples, the part representing the amount used is based on weight unless otherwise specified. In addition, the photocationic polymerization initiator “UVACURE 1590” (chemical name is described later) used in the following examples was obtained from the manufacturer Daicel Cytec Co., Ltd. in the form of a propylene carbonate solution. The amount of the active ingredient is displayed.

  Furthermore, in the following examples, as the ultraviolet absorber, a compound having the following trade name sold by BASF Japan Ltd. was used. In each case, what is indicated by “TINUVIN + number” is a trade name, followed by a chemical name or a component name. Each product name is displayed below.

TINUVIN 234: 2- [2-hydroxy-3,5-bis (α, α-dimethylbenzyl) phenyl] -2H-benzotriazole.
TINUVIN 384-2: 3- [3- (2H- benzotriazol-2-yl) -5-tert-butyl-4-hydroxyphenyl] C ₇ -C ₉ branched and linear alkyl mixture propionic acid.
TINUVIN 571: 2- (3-dodecyl-2-hydroxy-5-methylphenyl) benzotriazole.
TINUVIN 928: 2- [2-hydroxy-3- (α, α-dimethylbenzyl) -5
tert-octylphenyl] -2H-benzotriazole.
TINUVIN 1130: Reaction product of methyl 3- [3- (2H-benzotriazol-2-yl) -5-tert-butyl-4-hydroxyphenyl] propanoate and polyethylene glycol 300, generally having the following composition Have

[Production Example 1]: Preparation of Adhesive Composition The following components were mixed to prepare a stock solution of an ultraviolet curable adhesive composition.

(Ultraviolet curable adhesive composition stock solution)
3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexanecarboxylate (“Celoxide 2021P” manufactured by Daicel Chemical Industries, Ltd.) 75 parts Bis (3-ethyl-3-oxetanylmethyl) ether [manufactured by Toagosei Co., Ltd. “Aron Oxetane OXT-221” 25 parts 4,4′-bis (diphenylsulfonio) diphenyl sulfide Bishexafluorophosphate-based photocationic polymerization initiator (“UVACURE made by Daicel Cytec Co., Ltd.)
1590 ") 2.5 parts Silicone leveling agent (" SH710 "manufactured by Toray Dow Corning Co., Ltd.) 0.2 parts

[Example 1]
(A) Preparation of Adhesive Composition with Ultraviolet Absorber 100 parts of the ultraviolet curable adhesive composition prepared in Production Example 1 was mixed with 5 parts of “TINUVIN 234”, which is an ultraviolet absorber, to produce ultraviolet light. An adhesive composition with an absorbent was prepared.

(B) Measurement of transmittance of cured product of adhesive composition On one side of polyethylene terephthalate film ["Toyobo Ester Film E7002" manufactured by Toyobo Co., Ltd.] Using a bar coater [Daiichi Rika Co., Ltd.] The adhesive composition containing the UV absorber prepared in (a) above was applied, and the composition was cured by irradiating with UV light with an integrated light amount of 1,500 mJ / cm ² using the “D bulb” manufactured by Fusion UV Systems. I let you. The film thickness of the adhesive composition was adjusted by changing the number of the bar coater number so that the thickness after curing was 9 μm. The obtained cured product was peeled from the polyethylene terephthalate film, and the spectral absorption spectrum of the cured product film was measured using an ultraviolet-visible spectrophotometer (“UV2450” manufactured by Shimadzu Corporation). The transmittance at wavelengths of 380 nm and 500 nm was read from this spectral absorption spectrum, and the results are summarized in Table 1.

(C) Preparation of polarizing plate UV curable adhesive prepared in Production Example 1 using a bar coater [manufactured by Daiichi Rika Co., Ltd.] on one side of a 38 μm thick polyethylene terephthalate film containing no UV absorber. The composition (the undiluted solution as it was before the ultraviolet absorber was blended) was applied. Since the film thickness when the adhesive composition was applied varied depending on the viscosity, the number of the bar coater was changed and the thickness after curing was adjusted to about 2 μm. Next, a polyethylene terephthalate film having a coating film of this ultraviolet curable adhesive composition is applied to one side of a polarizing film in which iodine is adsorbed and oriented on a polyvinyl alcohol film so that the coating film surface and the polarizing film overlap. (Fuji Plastic Co., Ltd. product “LPA3301”). From the polyethylene terephthalate film side of this bonded product, the adhesive composition is cured by irradiating UV light with an integrated light amount of 1,500 mJ / cm ² using a “D bulb” manufactured by Fusion UV Systems, and one side of a polyvinyl alcohol polarizing film. A polarizing plate having a polyethylene terephthalate film bonded thereto was prepared.

(D) Production of optical layered product The polarizing plate produced in (c) above was cut into a size of 8 cm × 8 cm, and a bar coater (Daiichi Rika Co., Ltd.) was applied to the polyvinyl alcohol surface on which the polyethylene terephthalate film was not bonded. The adhesive composition with an ultraviolet absorber prepared in the above (a) was applied. Since the film thickness when the adhesive composition was applied varied depending on the viscosity, the number of the bar coater was changed and the thickness after curing was adjusted to about 2 μm.

Next, the polarizing plate which has the coating film of the said adhesive composition on one side of a transparent glass substrate (what becomes a liquid crystal cell substrate), so that the coating film side may become a bonding surface with a transparent glass substrate. Then, pasting was performed using a pasting device (“LPA3301” manufactured by Fuji Pla Co., Ltd.). From the polarizing plate side of this bonded product, ultraviolet rays were irradiated with a cumulative light quantity of 1,500 mJ / cm ² by a D bulb manufactured by Fusion UV Systems, and the adhesive composition was cured to prepare an optical laminate.

[Examples 2 to 8]
The kind and addition amount of the ultraviolet absorber in (a) of Example 1 were changed as shown in Table 1, and the resulting adhesive composition was cured in the same manner as in (b) of Example 1. The transmittance was measured and the results are summarized in Table 1. Moreover, the optical laminated body was produced like Example (d) except using each adhesive composition.

[Comparative Example 1]
In Example 1 (a), no UV absorber was added, and the UV curable adhesive composition prepared in Production Example 1 was used as it was and cured in the same manner as in Example 1 (b). The transmittance | permeability of the thing was measured and the result was put together in Table 1. Further, an optical laminate was produced in the same manner as in Example 1 (d) except that the stock solution of this ultraviolet curable adhesive composition was used as it was.

[Comparative Example 2]
Using a polarizing plate in which a polyethylene terephthalate film is bonded to one side of the polyvinyl alcohol polarizing film produced in (c) of Example 1, an acrylic pressure-sensitive adhesive is applied to the polyvinyl alcohol surface on which the polyethylene terephthalate film is not bonded. A layer was formed. The obtained pressure-sensitive adhesive polarizing plate was cut into a size of 8 cm × 8 cm, and the acrylic pressure-sensitive adhesive layer was bonded to one surface of the same transparent glass substrate used in (c) of Example 1. This bonded product was treated in a 50 ° C. autoclave at a pressure of 5 kg / cm ² (about 0.5 MPa) for 20 minutes to produce an optical laminate.

[Durability test of optical laminate]
A heat shock test was repeated 300 times for the optical laminates produced in the above examples and comparative examples, with the process of holding at -35 ° C. for 1 hour and holding at 70 ° C. for 1 hour as one cycle. . The polarizing plate after the test was visually observed and evaluated according to the following criteria, and the results are summarized in Table 1.

(Evaluation criteria for heat shock test)
○: No floating or peeling is observed on the polarizing film, and no cracks are observed.
X: Floating or peeling is not observed in the polarizing film, but cracks are observed.

  As shown in Table 1, in Comparative Example 1 in which the adhesive composition does not contain an ultraviolet absorber, the cured product (adhesive layer) has a high transmittance of 90% at a wavelength of 380 nm. There is a concern that active energy rays (ultraviolet rays) irradiated from the polarizing plate side reach the liquid crystal cell through the adhesive composition layer and affect the liquid crystal cell. On the other hand, in Examples 1 to 9, in which a predetermined amount of the ultraviolet absorber was blended into the adhesive composition, the transmittance of the cured product (adhesive layer) at a wavelength of 380 nm was as low as 30% or less, and the active energy The influence of the line (ultraviolet rays) on the liquid crystal cell is greatly reduced. In addition, even in the presence of the ultraviolet absorber in this way, the adhesive composition is cured by ultraviolet irradiation from the polarizing plate side, and the polarizing plate and the glass substrate are well bonded. It was confirmed by the result.

  On the other hand, in Comparative Example 2 in which an adhesive was used for bonding the polarizing plate and the glass substrate, the polarizing film was not lifted or peeled off by the heat shock test, and the polarizing plate and the glass substrate were adhered. Cracks were observed. This is presumably because the expansion and contraction of the polarizing film could not be sufficiently absorbed by the pressure-sensitive adhesive layer alone.

1 ... Liquid crystal cell substrate, 2 ... Adhesive layer, 5 ... Polarizing plate, 6 ... Polarizing film,
7: Transparent protective layer, 8: Resin layer, 10, 11, 12: Optical laminate.

Claims (4)

The surface of the polarizing film of the polarizing plate having a polarizing film in which iodine is adsorbed and oriented on a polyvinyl alcohol-based resin contains an epoxy-based compound having at least one epoxy group in the molecule. A glycidyl ether of a polyol having a cyclic ring, an aliphatic epoxy compound, or an alicyclic epoxy compound,
A step of forming a layer of an active energy ray-curable resin composition containing 10 to 20 parts by weight of an ultraviolet absorber per 100 parts by weight of the solid content of the composition;
Bonding the layer of the curable resin composition formed on the surface of the polarizing film to the liquid crystal cell substrate; and
The active energy ray is irradiated from the polarizing plate side was stuck to the liquid crystal cell substrate, comprising the step of an adhesive layer by curing the layer of curable resin composition,
The liquid crystal cell substrate, a manufacturing method of the optical stack, wherein that you have to configure the liquid crystal cell to sandwich the liquid crystal molecules between the other of the liquid crystal cell substrate.   The said polarizing plate is laminated | stacked on the single side | surface of the said polarizing film with the transparent protective layer which consists of a hardened | cured material of a thermoplastic resin film or an active energy ray curable resin composition, and thickness is 100 micrometers or less. A method for producing an optical laminate.   The said active energy ray-curable resin composition is a manufacturing method of the optical laminated body of Claim 1 or 2 which further contains an oxetane type compound.   The method for producing an optical laminate according to claim 1, wherein the adhesive layer has a thickness of 10 μm or less.

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