JP5750857B2 - 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 JP 2008-257199 A (Patent Document 3), a photo-curing property in which an alicyclic epoxy compound and an epoxy compound having no alicyclic epoxy group are combined and a photocationic polymerization initiator is further blended. A technique using an adhesive for bonding a polarizing film and a protective film is disclosed. This document describes that, when a photosensitizer made of an anthracene compound is used in combination, even when the protective film contains an ultraviolet absorber, a good adhesive force is given.

Japanese Patent No. 4306269 (Japanese Patent Laid-Open No. 2004-245924) Japanese Patent No. 4306270 (Japanese Patent Laid-Open No. 2004-245925) JP 2008-257199 A

  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, when the ultraviolet absorbing ability is imparted to the polarizing plate by means such as containing an ultraviolet absorbing agent in any film constituting the polarizing plate, the active energy rays do not reach the adhesive, and the adhesive May not cure. It is conceivable to control the irradiation amount of the active energy ray so that the irradiated active energy ray passes through the polarizing plate, but does not reach the liquid crystal cell, but frequently changing the irradiation amount, This is complicated.

  Accordingly, an object of the present invention is to form an optical laminate excellent in thin and lightweight properties and durability by bonding a polarizing plate and a liquid crystal cell substrate via an active energy ray-curable adhesive, and a polarizing plate. Even if it has a UV-absorbing ability, the adhesive can be appropriately cured. 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 0.3 to 10 parts by weight of a photosensitizer per 100 parts by weight of the solid content of the composition. An optical laminate that is a cured product of the resin 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 photosensitizer. The adhesive layer is preferably 10 μm or less in thickness.

  It is advantageous from the viewpoint of thin and light weight that the polarizing plate constituting the optical layered body has a film thickness of 200 μm or less. This polarizing plate has the above-described polarizing film and a transparent protective layer laminated on one side thereof, and is a liquid crystal cell on the surface opposite to the transparent protective layer of the polarizing film via the adhesive layer. It is advantageous in terms of reducing the thickness and weight. The polarizing plate has a transmittance of 5% or less with respect to light having a wavelength of 380 nm, and active energy rays irradiated from the polarizing plate side to the liquid crystal molecules in the liquid crystal cell in order to cure the curable resin composition. It is preferable to prevent the influence.

  Furthermore, according to the present invention, the surface of a polarizing plate having a polarizing film in which a dichroic dye is adsorbed and oriented on a polyvinyl alcohol resin contains an epoxy compound having at least one epoxy group in the molecule, and A step of forming a layer of an active energy ray-curable resin composition containing 0.3 to 10 parts by weight of a photosensitizer per 100 parts by weight of the solid content of the composition, on the liquid crystal cell substrate, on the surface of the polarizing plate The process of bonding the formed curable resin composition layer, and irradiating active energy rays from the polarizing plate bonded to the liquid crystal cell substrate, curing the curable resin composition layer, and an adhesive A method for producing an optical layered body including a step of forming a layer is also provided.

  The optical laminated body of the present invention is thinner and lighter than a conventional optical laminated body in which a polarizing plate is bonded to a liquid crystal cell substrate via an adhesive, and contributes to a thin and lightweight liquid crystal panel. . Also, the adhesion between the polarizing plate and the liquid crystal cell substrate is good. Furthermore, since a photosensitizer is included in the composition forming the adhesive layer, the active energy from the polarizing plate side of the optical laminate can be obtained even when any of the films constituting the polarizing plate has an ultraviolet absorbing ability. By irradiating the line, the adhesive can be appropriately cured. This optical laminated body can be particularly suitably applied to a large-sized liquid crystal display device such as a television. Moreover, 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 schematic diagram which shows another form of the layer structure of the optical laminated body which concerns on this invention.

  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, selectively hydrogenates 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, tetrahydroxy Examples thereof include polyfunctional compounds such as benzophenone 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 an alicyclic ring, hydrogenated bisphenol A diglycidyl ether is preferable.

  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. It is more preferably used because it imparts sex.

  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, the 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.

<Photosensitizer>
In the present invention, a photosensitizer 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. The photosensitizer used here should just be what shows maximum absorption to the light of wavelength longer than 380 nm. The aforementioned cationic photopolymerization initiator exhibits maximum absorption at a wavelength near or shorter than 300 nm, generates a cationic species or a Lewis acid in response to light having a wavelength in the vicinity thereof, and performs cationic polymerization of the cationically polymerizable compound. In order to start, in order to respond to light having a longer wavelength, a photosensitizer exhibiting maximum absorption is added to light having a wavelength longer than 380 nm.

  For example, carbonyl compounds, organic sulfur compounds, persulfides, redox compounds, azo and diazo compounds, halogen compounds, anthracene compounds, photoreducing dyes, and the like can be used as such photosensitizers. Anthracene compounds represented by

In the formula, R ¹ and R ² each independently represents an alkyl group having 1 to 6 carbon atoms or an alkoxyalkyl group having 2 to 12 carbon atoms, and R ³ represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.

Specific examples of the anthracene compound represented by the formula (I) include the following, and two or more of them may be used in combination as necessary.
9,10-dimethoxyanthracene,
9,10-diethoxyanthracene,
9,10-dipropoxyanthracene,
9,10-diisopropoxyanthracene,
9,10-dibutoxyanthracene,
9,10-dipentyloxyanthracene,
9,10-dihexyloxyanthracene,
9,10-bis (2-methoxyethoxy) anthracene,
9,10-bis (2-ethoxyethoxy) anthracene,
9,10-bis (2-butoxyethoxy) anthracene,
9,10-bis (3-butoxypropoxy) anthracene,
2-methyl- or 2-ethyl-9,10-dimethoxyanthracene,
2-methyl- or 2-ethyl-9,10-diethoxyanthracene,
2-methyl- or 2-ethyl-9,10-dipropoxyanthracene,
2-methyl- or 2-ethyl-9,10-diisopropoxyanthracene,
2-methyl- or 2-ethyl-9,10-dibutoxyanthracene,
2-methyl- or 2-ethyl-9,10-dipentyloxyanthracene,
2-methyl- or 2-ethyl-9,10-dihexyloxyanthracene and the like.

  By blending the photosensitizer with the active energy ray-curable resin composition, the curability of the curable resin composition is improved as compared with the case where the photosensitizer is not blended. Even when the transmittance is small, the curable resin composition can be appropriately cured. The compounding quantity of a photosensitizer shall be the range of 0.3-10 weight part per 100 weight part of solid content of an active energy ray curable resin composition. Preferably, it is 0.3 to 5 parts by weight, more preferably 0.3 to 3 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 resin composition, and may react in the subsequent curing treatment, but the adhesive after curing It means what remains in the agent 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 photosensitizer exceeds 10 parts by weight per 100 parts by weight of the solid content of the active energy ray-curable resin composition, problems such as coloring of the cured film and precipitation at low temperature storage may occur. On the other hand, when the blending amount is less than 0.3 parts by weight per 100 parts by weight of the solid content of the active energy ray-curable resin composition, the curing of the curable resin composition becomes insufficient, and the liquid crystal cell and the polarizing plate are not cured. It is difficult to obtain sufficient adhesive strength.

<Radically polymerizable compound that can be arbitrarily mixed>
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; other xanthones, fluorenones, 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>
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.

[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. The polarizing plate 5 is preferably composed of a material having a thickness of 200 μm or less, more preferably a material having a thickness of 100 μm or less, from the viewpoint of thinning the optical laminate 10 and the liquid crystal panel. Although the polarizing film itself as described above can be used alone as the polarizing plate 5, since the polarizing film alone is fragile, at least one surface thereof, particularly on the surface opposite to the surface bonded to the liquid crystal cell substrate 1 is used. Those provided with a transparent protective layer are preferably used.

  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.

  FIG. 3 is a schematic cross-sectional view showing another embodiment of the layer configuration of the optical laminate according to the present invention. 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.

  As described above, the polarizing plate 5 may have any layer as long as it includes the polarizing film 6, but the layers other than the polarizing film 6 are two layers or less, particularly one layer or two layers. It is preferable from the viewpoint of thinning the optical laminate or the liquid crystal panel while protecting the polarizing film 6. From such a point of view, as shown in FIG. 2, the polarizing film 6 has a transparent protective layer 7 on one side and is directly on the polarizing film surface made of a polyvinyl alcohol-based resin on the side opposite to the transparent protective layer 7. The form of being bonded to the liquid crystal cell substrate 1 via the adhesive layer 2 is one of the preferred ones.

  The polarizing plate 5 preferably has an ultraviolet absorbing ability from the viewpoint of preventing problems that are likely to occur in the liquid crystal cell due to irradiation with active energy rays. Specifically, the transmittance for light having a wavelength of 380 nm is preferably 5% or less. In the present invention, a photosensitizer is blended in the curable resin composition forming the adhesive layer 2, and as described above, the photosensitizer has absorption in a wavelength region of 380 nm or more, and therefore has a wavelength of 380 nm. The transmittance of the polarizing plate 5 with respect to this light may be substantially zero. However, in general, a certain degree of transmittance with respect to light of this wavelength, for example, 0.1% or more, is advantageous in reliably curing the curable resin composition to be the adhesive layer 2. is there.

<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>
The transparent protective layer 7 provided on one side of the polarizing film 6 and the resin layer 8 provided on the opposite side as necessary include, for example, cellulose acetate resin, cycloolefin resin, polyolefin resin, acrylic resin, polyimide An appropriate thermoplastic resin film that has been widely used in the art as a material for forming a protective layer, such as a resin based on resin, a polycarbonate based resin, or a polyester based resin, can be used. Moreover, the transparent protective layer 7 can also be comprised with the hardened | cured material of an active energy ray curable resin composition. Among these, from the viewpoint of mass productivity and adhesiveness, it is preferable that the transparent protective layer 7 be a film made of a cellulose acetate-based resin or a cycloolefin-based resin, or a cured product of an active energy ray-curable resin composition. . 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.

  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-type compounds, oxetane-type compounds, and a photocationic polymerization initiator, the description similar to what was carried out about the adhesive bond layer 2 applies previously.

  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.

  When the form shown in FIG. 2 or the form shown in FIG. 3 is adopted, the transparent protective layer 7 is composed of a film containing an ultraviolet absorber or a cured product of a curable resin composition containing an ultraviolet absorber. By doing so, the polarizing plate 5 can be provided with ultraviolet absorbing ability. In this case, the transmittance of the transparent protective layer 7 for light having a wavelength of 380 nm is preferably 10% or less. The ultraviolet absorber can be an appropriate compound that absorbs in the ultraviolet region, such as benzotriazole, benzophenone, and salicylic acid ester.

<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) An epoxy compound having at least one epoxy group in the molecule is contained on the surface of the polarizing plate 5 having a polarizing film in which a dichroic dye is adsorbed and oriented on a polyvinyl alcohol resin. A curable resin composition layer forming step of forming a layer of an active energy ray-curable resin composition containing 0.3 to 10 parts by weight of a photosensitizer per 100 parts by weight of a solid content;
(2) A bonding step in which a layer of the curable resin composition formed on the surface of the polarizing plate 5 in the curable resin composition layer forming step is bonded 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, the polarizing plate 5 may be a polarizing film alone, or may be one in which other layers are laminated in advance as described above. When forming a transparent protective layer made of a cured product of an active energy ray curable resin composition on one side of a polarizing film, or when laminating a film via an adhesive made of an active energy ray curable resin composition, the above In the curing step, it is also possible to cure the transparent protective layer or the adhesive for bonding the polarizing film and another film simultaneously with the curing of the curable resin composition layer to be the adhesive layer 2. . 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, a polarizing plate 5 having a transparent protective layer 7 made of a resin film on one side of the polarizing film 6 as shown in FIG. 2, or a resin made of a film on the other side of the polarizing film 6 as shown in FIG. In the case where the polarizing plate 5 having the layer 8 is used, and the polarizing film 6 and the transparent protective layer 7 and the polarizing film 6 and the resin layer 8 are bonded with an adhesive made of a curable resin composition, A curable resin composition is applied to the bonding surface of the polarizing film 6, the transparent protective layer 7 and / or the resin layer 8, and the polarizing film 6 and the transparent protective layer 7 (and / or the resin film 8 are interposed via the composition layer). In the same manner as above, after obtaining a laminated product laminated in the order of the liquid crystal cell substrate 1 / curable resin composition layer / polarizing plate 5, the same as above. The active energy ray may be irradiated by the method described above.

  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 laminates 10 to 12 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. By doing so, it can be set as 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 the liquid crystal is sealed between the two liquid crystal cell substrates is the liquid crystal cell substrate 1 in FIGS. 1 to 3, and a polarizing plate is bonded to one or both surfaces according to the present invention. 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, the photosensitizers used in the following examples are all compounds having the following trade names obtained from Kawasaki Kasei Kogyo Co., Ltd., and are indicated by the respective trade names below. However, in the table, the title “ANTHRACURE” is omitted and only the numbers are displayed.

ANTHRACURE UVS-1221: 9,10-dipropoxyanthracene,
ANTHRACURE UVS-1331: 9,10-dibutoxyanthracene.

[Production Example 1] (Preparation of adhesive composition)
The following components were mixed to prepare an ultraviolet curable adhesive composition A.

(UV curable adhesive composition A)
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" manufactured 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) Polarizing plate using triacetyl cellulose as a protective film A triacetyl cellulose film having a thickness of 40 μm and containing an ultraviolet absorber on one side of a polarizing film in which iodine is adsorbed and oriented on a polyvinyl alcohol film (for light having a wavelength of 380 nm) A polarizing plate (“SR0661A-XNSY” manufactured by Sumitomo Chemical Co., Ltd., thickness of about 70 μm) was prepared, which had a transmittance of 7%) bonded via a polyvinyl alcohol-based adhesive. This polarizing plate exhibited a transmittance of 1.3% with respect to light having a wavelength of 380 nm.

(B) Preparation of Photosensitizer-Containing Adhesive Composition 100 parts of the UV curable adhesive composition A prepared in Production Example 1 were subjected to a photosensitizer “ANTHRACURE UVS-1221” of 0. Three parts were mixed to prepare an adhesive composition containing a photosensitizer.

(C) Production of Optical Laminate The polarizing plate prepared in (a) 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 triacetyl cellulose film was not bonded. The adhesive composition with a photosensitizer prepared in the above (b) was applied. Since the film thickness when applying the adhesive composition varies depending on the viscosity, the number of the bar coater's number line was changed to adjust the film thickness after curing to 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 an integrated light amount 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]
An optical laminate was prepared in the same manner as in Example 1 except that the type and addition amount of the photosensitizer in Example 1 (b) were changed as shown in Table 1.

[Example 9]
(A) Production of polarizing plate using polyethylene terephthalate as a protective film A bar coater [first rationalization (on the one side) of a 38 μm thick polyethylene terephthalate film (transmittance of 2% for light of wavelength 380 nm) containing an ultraviolet absorber The UV curable adhesive composition A prepared in Production Example 1 was applied so that the thickness after curing was 2 μm. Next, a polyethylene terephthalate film having a coating film of this ultraviolet curable adhesive composition A is pasted on 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. Bonding was performed using an apparatus ("LPA3301" manufactured by Fuji Plastics Co., Ltd.). From the polarizing film side of this bonded product, ultraviolet rays are irradiated with an integrated light amount of 1,500 mJ / cm ² by a “D bulb” manufactured by Fusion UV Systems, to cure the ultraviolet curable adhesive composition A, and ultraviolet rays are applied to one side. A polarizing plate on which an absorbent polyethylene terephthalate film was bonded was prepared. This polarizing plate exhibited a transmittance of 0.2% with respect to light having a wavelength of 380 nm.

(B) Preparation of Photosensitizer-Containing Adhesive Composition 100 parts of the UV curable adhesive composition A prepared in Production Example 1 were subjected to a photosensitizer “ANTHRACURE UVS-1221” of 0. 5 parts was mixed to prepare an adhesive composition containing a photosensitizer.

(C) Production of optical laminate The polarizing plate having a polyethylene terephthalate film on one side produced in (a) above and the adhesive composition containing a photosensitizer prepared in (b) above were used. An optical laminate was prepared in the same manner as in (c).

[Examples 10 and 11]
An optical laminate was prepared in the same manner as in Example 9 except that the addition amount of the photosensitizer in Example 9 (b) was changed as shown in Table 1.

[Comparative Example 1]
The optical laminate was prepared in the same manner as in Example 1 except that the photosensitizer was not added in Example 1 (b), and the ultraviolet curable adhesive composition part A prepared in Production Example 1 was used as it was. Produced.

[Comparative Example 2]
In Example 1 (b), the optical laminate was produced in the same manner as in Example 1 except that the addition amount of the photosensitizer was changed to 0.1 part.

[Comparative Example 3]
The optical laminate was prepared in the same manner as in Example 9, except that the photosensitizer was not added in Example 9 (b), and the ultraviolet curable adhesive composition part A prepared in Production Example 1 was used as it was. Produced.

[Comparative Example 4]
Using a polarizing plate having a triacetyl cellulose film bonded to the same side as shown in (a) of Example 1, an acrylic pressure-sensitive adhesive layer is applied to the polyvinyl alcohol surface to which the triacetyl cellulose film is not bonded. Formed. This 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.

[Adhesion durability test of optical laminates]
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.
(Triangle | delta): Although a float and peeling are not recognized by a polarizing film, a crack is recognized.
X: Floating or peeling is observed in the polarizing film.

  As shown in Table 1, Comparative Examples 1 and 3 in which the adhesive composition does not contain a photosensitizer, and Comparative Example 2 that contains a photosensitizer but its amount is small in a polarizing film by a heat shock test. Floating and peeling were observed. This is presumably because the adhesive composition layer was not sufficiently cured. On the other hand, in Comparative Example 4 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 shrinkage of the polarizing film could not be sufficiently absorbed by the pressure-sensitive adhesive layer alone.

  On the other hand, Examples 1-11 using the adhesive composition in which the photosensitizer of the quantity prescribed | regulated by this invention was mix | blended are not recognized in the polarizing film by a heat shock test, and peeling is not recognized. In other words, the polarizing plate or the optical laminate had good durability while being thinned.

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 (5)

A liquid crystal cell substrate and a polarizing plate having a thickness of 100 μm or less in which a transparent protective layer is laminated on one side of a polarizing film in which a dichroic dye is adsorbed and oriented on a polyvinyl alcohol-based resin, the polarizing film in the polarizing plate On the surface opposite to the transparent protective layer, it is bonded to the liquid crystal cell substrate via an adhesive layer,
The adhesive layer contains an epoxy compound having at least one epoxy group in the molecule, and further contains 0.3 to 10 parts by weight of a photosensitizer per 100 parts by weight of the solid content of the composition. An optical laminate characterized by being a cured product of an energy ray curable resin composition (provided that the active energy ray curable resin composition contains 4-hydroxybutyl acrylate glycidyl ether in a (meth) acrylic polymer). It does not contain a modified acrylic graft polymer in which the chain is graft-polymerized and a trimethylolpropane adduct of xylene diisocyanate.)   The optical laminate according to claim 1, wherein the active energy ray-curable resin composition further contains an oxetane compound.   The optical laminate according to claim 1, wherein the adhesive layer has a thickness of 10 μm or less.   The optical laminate according to claim 1, wherein the polarizing plate has a transmittance of 5% or less for light having a wavelength of 380 nm. The surface of the polarizing film of the polarizing plate having a polarizing film in which a dichroic dye is adsorbed and oriented on a polyvinyl alcohol resin contains an epoxy compound having at least one epoxy group in the molecule, and Forming a layer of an active energy ray-curable resin composition containing 0.3 to 10 parts by weight of a photosensitizer per 100 parts by weight of a solid content,
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 irradiating active energy rays from the polarizing plate side bonded to the liquid crystal cell substrate; A method for producing an optical laminate comprising a step of curing a layer of the composition to form an adhesive layer (provided that the active energy ray-curable resin composition is added to a (meth) acrylic polymer). (It does not contain a modified acrylic graft polymer obtained by graft polymerization of a chain containing hydroxybutyl acrylate glycidyl ether and a trimethylolpropane adduct of xylene diisocyanate) .

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