WO2020230717A1 - Polarizing plate, method for manufacturing polarizing plate, and image display device using said polarizing plate - Google Patents

Polarizing plate, method for manufacturing polarizing plate, and image display device using said polarizing plate Download PDF

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Publication number
WO2020230717A1
WO2020230717A1 PCT/JP2020/018656 JP2020018656W WO2020230717A1 WO 2020230717 A1 WO2020230717 A1 WO 2020230717A1 JP 2020018656 W JP2020018656 W JP 2020018656W WO 2020230717 A1 WO2020230717 A1 WO 2020230717A1
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WO
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Prior art keywords
urea
polarizing plate
adhesive layer
image display
adhesive
Prior art date
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PCT/JP2020/018656
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French (fr)
Japanese (ja)
Inventor
福田　謙一
亮 内藤
Original Assignee
住友化学株式会社
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Publication date
Application filed by 住友化学株式会社 filed Critical 住友化学株式会社
Priority to KR1020217040578A priority Critical patent/KR20220006626A/en
Priority to CN202080034704.4A priority patent/CN113811797A/en
Publication of WO2020230717A1 publication Critical patent/WO2020230717A1/en

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Classifications

    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K59/00—Integrated devices, or assemblies of multiple devices, comprising at least one organic light-emitting element covered by group H10K50/00
    • H10K59/80—Constructional details
    • H10K59/8791—Arrangements for improving contrast, e.g. preventing reflection of ambient light
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/30—Polarising elements
    • G02B5/3025—Polarisers, i.e. arrangements capable of producing a definite output polarisation state from an unpolarised input state
    • G02B5/3033—Polarisers, i.e. arrangements capable of producing a definite output polarisation state from an unpolarised input state in the form of a thin sheet or foil, e.g. Polaroid
    • G02B5/3041—Polarisers, i.e. arrangements capable of producing a definite output polarisation state from an unpolarised input state in the form of a thin sheet or foil, e.g. Polaroid comprising multiple thin layers, e.g. multilayer stacks
    • G02B5/305—Polarisers, i.e. arrangements capable of producing a definite output polarisation state from an unpolarised input state in the form of a thin sheet or foil, e.g. Polaroid comprising multiple thin layers, e.g. multilayer stacks including organic materials, e.g. polymeric layers
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B15/00—Layered products comprising a layer of metal
    • B32B15/04—Layered products comprising a layer of metal comprising metal as the main or only constituent of a layer, which is next to another layer of the same or of a different material
    • B32B15/08—Layered products comprising a layer of metal comprising metal as the main or only constituent of a layer, which is next to another layer of the same or of a different material of synthetic resin
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B27/00—Layered products comprising a layer of synthetic resin
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B27/00—Layered products comprising a layer of synthetic resin
    • B32B27/18—Layered products comprising a layer of synthetic resin characterised by the use of special additives
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B27/00—Layered products comprising a layer of synthetic resin
    • B32B27/30—Layered products comprising a layer of synthetic resin comprising vinyl (co)polymers; comprising acrylic (co)polymers
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B7/00—Layered products characterised by the relation between layers; Layered products characterised by the relative orientation of features between layers, or by the relative values of a measurable parameter between layers, i.e. products comprising layers having different physical, chemical or physicochemical properties; Layered products characterised by the interconnection of layers
    • B32B7/02—Physical, chemical or physicochemical properties
    • B32B7/023—Optical properties
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B7/00—Layered products characterised by the relation between layers; Layered products characterised by the relative orientation of features between layers, or by the relative values of a measurable parameter between layers, i.e. products comprising layers having different physical, chemical or physicochemical properties; Layered products characterised by the interconnection of layers
    • B32B7/04—Interconnection of layers
    • B32B7/12—Interconnection of layers using interposed adhesives or interposed materials with bonding properties
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J129/00—Adhesives based on homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by an alcohol, ether, aldehydo, ketonic, acetal, or ketal radical; Adhesives based on hydrolysed polymers of esters of unsaturated alcohols with saturated carboxylic acids; Adhesives based on derivatives of such polymers
    • C09J129/02—Homopolymers or copolymers of unsaturated alcohols
    • C09J129/04—Polyvinyl alcohol; Partially hydrolysed homopolymers or copolymers of esters of unsaturated alcohols with saturated carboxylic acids
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J201/00—Adhesives based on unspecified macromolecular compounds
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J7/00—Adhesives in the form of films or foils
    • C09J7/30—Adhesives in the form of films or foils characterised by the adhesive composition
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/30—Polarising elements
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333—Constructional arrangements; Manufacturing methods
    • G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F3/00—Input arrangements for transferring data to be processed into a form capable of being handled by the computer; Output arrangements for transferring data from processing unit to output unit, e.g. interface arrangements
    • G06F3/01—Input arrangements or combined input and output arrangements for interaction between user and computer
    • G06F3/03—Arrangements for converting the position or the displacement of a member into a coded form
    • G06F3/041—Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B33/00—Electroluminescent light sources
    • H05B33/02—Details
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K59/00—Integrated devices, or assemblies of multiple devices, comprising at least one organic light-emitting element covered by group H10K50/00
    • H10K59/80—Constructional details
    • H10K59/87—Passivation; Containers; Encapsulations
    • H10K59/871—Self-supporting sealing arrangements
    • H10K59/8722—Peripheral sealing arrangements, e.g. adhesives, sealants

Definitions

  • the present invention relates to a polarizing plate and a method for producing the same. Further, the present invention relates to an image display device in which one surface of the polarizing plate is bonded to an image display cell and the other surface is bonded to a transparent member such as a touch panel or a front plate.
  • Liquid crystal display devices are widely used not only in liquid crystal televisions, but also in mobile devices such as personal computers and mobile phones, and in-vehicle applications such as car navigation systems.
  • a liquid crystal display device has a liquid crystal panel member in which polarizing plates are attached to both sides of a liquid crystal cell with an adhesive, and display is performed by controlling the light from the backlight member by the liquid crystal panel member.
  • organic EL display devices like liquid crystal display devices, have been widely used in mobile applications such as televisions and mobile phones, and in-vehicle applications such as car navigation systems.
  • a circular polarizing plate (polarizing element and ⁇ / 4 plate) is formed on the visible side surface of the image display panel.
  • a laminate containing the above, which may be simply referred to as a polarizing plate below) may be arranged.
  • polarizing plates are increasingly mounted on automobiles as members of liquid crystal display devices and organic EL display devices.
  • Polarizing plates used in in-vehicle image display devices are often exposed to high-temperature environments and have less change in characteristics at higher temperatures than other mobile applications such as televisions and mobile phones. High temperature durability) is required.
  • a front plate such as a transparent resin plate or a glass plate (also referred to as a "window layer” or the like) is further visible side than the polarizing plate of the image display panel.
  • the number of configurations that provide ()) is increasing.
  • a display device provided with a touch panel a configuration in which a touch panel is provided on the viewing side of the image display panel on the viewing side and a front plate is provided on the viewing side of the image display panel is widely adopted.
  • an air layer exists between the image display panel and a transparent member such as a front plate or a touch panel
  • external light is reflected due to reflection of light at the interface of the air layer, and the visibility of the screen is improved.
  • the space between the polarizing plate and the front transparent member arranged on the visible surface of the image display panel is filled with a material having a refractive index close to that of these materials (hereinafter, may be referred to as an "interlayer filling structure").
  • an adhesive or a UV curable adhesive is used for the purpose of suppressing deterioration of visibility due to reflection at the interface and adhesively fixing the members to each other (see, for example, Patent Document 1).
  • the above-mentioned interlayer filling configuration is widely adopted in mobile applications such as mobile phones, which are often used outdoors. Further, due to the increasing demand for visibility in recent years, even in in-vehicle applications such as car navigation devices, a front plate is arranged on the surface of an image display panel, and the space between the panel and the front plate is filled with an adhesive layer or the like. Adoption of the configuration is being considered. However, when such a configuration is adopted, as a result of a heating durability test (200 hours at 95 ° C., etc.), a significant decrease in transmittance is observed in the central portion of the polarizing plate surface, while the polarizing plate alone is used. It has been reported that no significant decrease in transmittance is observed even at 95 ° C. for 1000 hours.
  • Patent Document 2 the significant decrease in the transmittance of the polarizing plate in a high temperature environment is caused by one surface of the polarizing plate being an image display cell. It has also been reported that this is a problem peculiar to an image display device that employs an interlayer filling configuration in which the other surface is bonded to a transparent member such as a touch panel or a front plate when exposed to a high temperature environment.
  • the present inventors performed Raman spectroscopic measurement of samples subjected to high-temperature durability test at interlayer filling configuration, in accordance with the decrease in the transmittance, increase the sum of the peak area in the vicinity of 1100 cm -1 and around 1500 cm -1 I'm observing what I'm doing.
  • Patent Document 2 as a solution to the problem, the amount of water per unit area of the polarizing plate is set to a specified amount or less, and the saturated water absorption amount of the transparent protective film adjacent to the polarizing element is set to a specified amount or less to increase the transmittance.
  • the effect of suppressing the decrease of the above solution is not always sufficient, and further, a polarizing plate or a polarizing plate is attached in order to reduce the water content of the polarizing plate at the time of panel fabrication. It has been found that the panel needs to be heated, which causes a new problem of reducing the productivity of the panel.
  • the problem of the present invention that is, the problem to be solved by the present invention, is that even when the image display device has an interlayer filling configuration, the transmittance is lowered in a high temperature environment. It is an object of the present invention to provide a polarizing plate which is small and has excellent durability and a method for producing the same. Yet another object of the present invention is to provide a durable image display device having improved display characteristics in a high temperature environment.
  • urea-based compounds urea-based compounds
  • the layer becomes an adhesive layer.
  • the interlayer filling configuration has an effect of suppressing a decrease in transmittance in a high temperature environment.
  • the urea derivative or the thiourea derivative not only has an excellent effect of suppressing a decrease in transmittance in a high temperature environment, but also polarizes in a high temperature environment. It was also found that it shows excellent performance in the effect of suppressing the decrease in degree (suppressing cross omission). The present inventors have completed the present invention based on such newly found facts.
  • the total content of the urea-based compound contained in the adhesive layer is 1 part by weight or more and 400 parts by weight or less with respect to 100 parts by weight of the polyvinyl alcohol-based resin.
  • a method for manufacturing a polarizing plate in which a transparent protective film is bonded to at least one surface of a polarizing element On at least one surface of a polarizing element made of a stretched polyvinyl alcohol-based resin film in which iodine is adsorbed and oriented, A step of forming an adhesive layer using an adhesive composition containing a polyvinyl alcohol-based resin and at least one selected from urea, a urea derivative, thiourea and a thiourea derivative.
  • a method for producing a polarizing plate which comprises a step of laminating a transparent protective film through the adhesive layer at the same time as or after the step of forming the adhesive layer.
  • the present invention it is possible to provide a polarizing plate having a small decrease in transmittance in a high temperature environment and excellent high temperature durability even when used in an image display device having an interlayer filling configuration, and a method for manufacturing the same. Further, by using the polarizing plate of the present invention, it is possible to provide a display device in which a decrease in transmittance is suppressed in a high temperature environment.
  • the adhesive layer in a configuration in which a transparent protective film is provided on at least one surface of a polarizing element formed by adsorbing and orienting iodine on a polyvinyl alcohol-based resin layer via an adhesive layer, the adhesive layer is provided. It contains at least one selected from urea, urea derivatives, thiourea and thiourea derivatives.
  • a well-known polarizing element can be used as the polarizing element in which iodine is adsorbed and oriented on the polyvinyl alcohol (hereinafter, also referred to as PVA) -based resin layer of the present invention.
  • PVA polyvinyl alcohol
  • Such a polarizing element is generally formed by using a PVA-based resin film, dyeing the PVA-based resin film with iodine, and uniaxially stretching the film.
  • the PVA-based resin as described above, generally, one obtained by saponifying a polyvinyl acetate-based resin is used.
  • the degree of saponification is about 85 mol% or more, preferably about 90 mol% or more, and more preferably about 99 mol% to 100 mol%.
  • the polyvinyl acetate-based resin include polyvinyl acetate, which is a homopolymer of vinyl acetate, and a copolymer of vinyl acetate and another monomer copolymerizable therewith, for example, ethylene-vinyl acetate copolymer weight. Coalescence etc. can be mentioned.
  • Examples of other copolymerizable monomers include unsaturated carboxylic acids, olefins, vinyl ethers, unsaturated sulfonic acids and the like.
  • the degree of polymerization of the PVA-based resin is 1000 to 10000, preferably 1500 to 5000.
  • This PVA-based resin may be modified, and may be, for example, polyvinyl formal, polyvinyl acetal, polyvinyl butyral, etc. modified with aldehydes.
  • the method for manufacturing the polarizing element is not particularly limited, but a method of feeding out a polyvinyl alcohol-based resin film wound in a roll shape in advance and performing stretching, dyeing, cross-linking, etc., or a polyvinyl alcohol-based resin and a resin base material for stretching.
  • a method including a step of producing a laminated body of the above and stretching in the state of the laminated body is typical. In the present invention, any of these methods can be used. Methods for manufacturing these polarizing elements are described in paragraphs [0109] to [0128] of JP2014-48497A, and these methods can be used in the present invention.
  • the thickness of the polarizing element of the present invention is preferably 3 to 35 ⁇ m, more preferably 4 to 30 ⁇ m, and even more preferably 5 to 25 ⁇ m.
  • the polarizing plate of the present invention is a urea-based compound containing at least one selected from urea, a urea derivative, a thiourea and a thiourea derivative formed on at least one surface of a polyvinyl alcohol-based resin polarizing element formed by adsorbing and orienting iodine. It has a containing layer.
  • the urea-based compound-containing layer does not have to be an adhesive layer, but it is preferable that the adhesive layer contains a urea-based compound from the viewpoint of productivity.
  • the adhesive layer is formed by the following adhesive. The structure of the urea-based compound-containing layer other than the adhesive layer will be described later.
  • any suitable adhesive can be used as the adhesive for adhering the protective film to the polarizing element.
  • a water-based adhesive, a solvent-based adhesive, an active energy ray-curable type, or the like can be used, but a water-based adhesive is preferable.
  • the adhesive layer is a urea-based compound-containing layer
  • the adhesive contains at least one selected from urea, urea derivatives, thiourea and thiourea derivatives.
  • the thickness of the adhesive when applied can be set to any appropriate value. For example, after curing or heating (drying), an adhesive layer having a desired thickness is set so as to be obtained.
  • the thickness of the adhesive layer is preferably 0.01 ⁇ m to 7 ⁇ m, more preferably 0.01 ⁇ m to 5 ⁇ m, still more preferably 0.01 ⁇ m to 2 ⁇ m, and most preferably 0.01 ⁇ m to 1 ⁇ m.
  • any suitable water-based adhesive can be adopted.
  • a water-based adhesive containing a PVA-based resin PVA-based adhesive
  • the average degree of polymerization of the PVA-based resin contained in the water-based adhesive is preferably about 100 to 5500, more preferably 1000 to 4500, from the viewpoint of adhesiveness.
  • the average saponification degree is preferably about 85 mol% to 100 mol%, and more preferably 90 mol% to 100 mol% from the viewpoint of adhesiveness.
  • the PVA-based resin contained in the water-based adhesive is preferably one containing an acetoacetyl group, because the PVA-based resin layer has excellent adhesion to the protective film and has excellent durability. ..
  • the acetoacetyl group-containing PVA-based resin can be obtained, for example, by reacting the PVA-based resin with diketene by an arbitrary method.
  • the degree of acetoacetyl group modification of the acetoacetyl group-containing PVA resin is typically 0.1 mol% or more, preferably about 0.1 mol% to 20 mol%.
  • the resin concentration of the water-based adhesive is preferably 0.1% by weight to 15% by weight, more preferably 0.5% by weight to 10% by weight.
  • the water-soluble PVA-based adhesive that can be preferably used in the present invention may contain a cross-linking agent in addition to the above-mentioned PVA-based resin and urea-based compound, if necessary.
  • a cross-linking agent a known cross-linking agent can be used.
  • water-soluble epoxy compounds, dialdehydes, isocyanates and the like can be mentioned.
  • the cross-linking agent is preferably any one of glyoxal, glyoxyphosphate, and methylolmelamine, and may be glyoxal or glyoxalate. Glyoxal is preferable, and glyoxal is particularly preferable.
  • the water-soluble PVA-based adhesive of the present invention may contain an organic solvent.
  • alcohols are preferable because they are miscible with water, and methanol or ethanol is more preferable among the alcohols.
  • some urea derivatives have low solubility in water, but some have sufficient solubility in alcohol.
  • one of the preferred embodiments is to dissolve in alcohol to prepare an alcohol solution of the urea derivative, and then add the alcohol solution of the urea derivative to the PVA aqueous solution to prepare an adhesive.
  • any suitable adhesive can be used as long as it is an adhesive that can be cured by irradiation with active energy rays.
  • the active energy ray-curable adhesive include an ultraviolet curable adhesive and an electron beam-curable adhesive.
  • Specific examples of the curing type of the active energy ray-curing adhesive include a radical curing type, a cation curing type, an anion curing type, and a combination thereof (for example, a hybrid of a radical curing type and a cation curing type).
  • the active energy ray-curable adhesive is, for example, an adhesive containing a compound having a radically polymerizable group such as a (meth) acrylate group or a (meth) acrylamide group (for example, a monomer and / or an oligomer) as a curing component.
  • a compound having a radically polymerizable group such as a (meth) acrylate group or a (meth) acrylamide group (for example, a monomer and / or an oligomer) as a curing component.
  • a compound having a radically polymerizable group such as a (meth) acrylate group or a (meth) acrylamide group (for example, a monomer and / or an oligomer) as a curing component.
  • Specific examples of the active energy ray-curable adhesive and a curing method thereof are described in, for example, Japanese Patent Application Laid-Open No. 2012-144690.
  • the adhesive layer contains at least one selected from urea, urea derivatives, thiourea and thiourea derivatives.
  • a method for incorporating the urea-based compound in the adhesive layer it is preferable to include the urea-based compound in the above-mentioned adhesive.
  • a part of the urea-based compound may be transferred from the adhesive layer to the polarizing element or the like.
  • water-soluble and poorly water-soluble urea compounds and both urea compounds can be used in the present invention.
  • a poorly water-soluble urea compound is used as a water-soluble adhesive, it is preferable to devise a dispersion method so that haze does not increase after the adhesive layer is formed.
  • the amount of the urea-based compound added is preferably 0.1 to 400 parts by weight with respect to 100 parts by weight of the PVA-based resin, and 1 to 200 parts by weight. It is more preferable that the amount is 3 to 100 parts by weight.
  • the urea derivative means a compound having a molecular structure in which a part of urea is substituted with a substituent.
  • the urea derivative it is preferable that at least one of the four hydrogen atoms of the urea molecule is a compound substituted with a substituent.
  • the substituent is not particularly limited, but is preferably a substituent composed of a carbon atom, a hydrogen atom and an oxygen atom.
  • urea derivatives include methyl urea, ethyl urea, propyl urea, butyl urea, isobutyl urea, N-octadecyl urea, 2-hydroxyethyl urea, hydroxyurea, acetylurea, allylurea, and 2-propynyl as monosubstituted ureas.
  • Examples thereof include urea, cyclohexyl urea, phenyl urea, 3-hydroxyphenyl urea, (4-methoxyphenyl) urea, benzyl urea, benzoyl urea, o-tolyl urea and p-tolyl urea.
  • tetra-substituted urea tetramethylurea, 1,1,3,3-tetraethylurea, 1,1,3,3-tetrabutylurea, 1,3-dimethoxy-1,3-dimethylurea, 1,3-dimethyl- Examples thereof include 2-imidazolidinone and 1,3-dimethyl-3,4,5,6-tetrahydro-2 (1H) -pyrimidinone.
  • the thiourea derivative means a compound having a molecular structure in which a part of thiourea is substituted with a substituent.
  • the thiourea derivative is preferably a compound in which at least one of the four hydrogen atoms of the thiourea molecule is substituted with a substituent.
  • the substituent is not particularly limited, but is preferably a substituent composed of a carbon atom, a hydrogen atom and an oxygen atom.
  • thiourea derivative examples include N-methylthiourea, ethylthiourea, propylthiourea, isopropylthiourea, 1-butylthiourea, cyclohexylthiourea, N-acetylthiourea, and N-allylthiourea, (2) as monosubstituted thioureas.
  • Examples of the 3-substituted thiourea include trimethylthiourea, and examples of the 4-substituted thiourea include tetramethylthiourea and 1,1,3,3-tetraethylthiourea.
  • a urea derivative or a thiourea derivative is preferable because, when used in an image display device having an interlayer filling structure, the decrease in transmittance is small and the decrease in polarization degree is small in a high temperature environment.
  • Derivatives are more preferred.
  • the urea derivatives mono-substituted urea or di-substituted urea is preferable, and mono-substituted urea is more preferable.
  • the di-substituted urea includes 1,1-substituted urea and 1,3-substituted urea, but 1,3-substituted urea is more preferable.
  • the transparent protective film used in the present invention (hereinafter, also simply referred to as “protective film”) is attached to at least one side of the polarizing element via the urea-based compound-containing adhesive layer of the present invention.
  • This transparent protective film is attached to one side or both sides of the polarizing element, but it is more preferable that the transparent protective film is attached to both sides.
  • only one of the adhesive layers on both sides of the polarizing element is the urea-based compound-containing adhesive of the present invention.
  • it may be an agent layer it is more preferable that both adhesive layers are the urea-based compound-containing adhesive layer of the present invention.
  • polarizing plates having a protective film on only one side of the polarizing element have been developed. Even in this configuration, it is preferable to laminate the protective film via the urea-based compound-containing adhesive layer of the present invention.
  • a method for producing a polarizing plate having a protective film on only one side of the polarizing element a method of first producing a polarizing plate in which a protective film is bonded to both sides via an adhesive layer and then peeling off one of the protective films is conceivable.
  • only one of the adhesive layers may be the adhesive layer of the present invention, but the urea-based compound-containing adhesive layer of the present invention is the polarizing element.
  • the film-side adhesive layer that does not peel off is the urea-based compound-containing adhesive layer of the present invention.
  • the protective film may have other optical functions at the same time, and may be formed in a laminated structure in which other layers are laminated.
  • the film thickness of the protective film at this time is preferably thin from the viewpoint of optical characteristics, but if it is too thin, the strength is lowered and the workability is inferior.
  • the appropriate film thickness is 5 to 100 ⁇ m, preferably 10 to 80 ⁇ m, and more preferably 15 to 70 ⁇ m.
  • the protective film a film such as a cellulose acylate resin film, a polycarbonate resin film, a cycloolefin resin film such as norbornene, a (meth) acrylic polymer film, or a polyester resin film such as polyethylene terephthalate is used. be able to.
  • the protective film on at least one side is a cellulose acylate-based film or (meth) in terms of moisture permeability.
  • Any of the acrylic polymer films is preferable, and the cellulose acylate film is particularly preferable.
  • At least one protective film may have a retardation function for the purpose of compensating the viewing angle, and in that case, the film itself may have a retardation function and has a separate retardation layer. It may be a combination of both.
  • the polarizing plate of the present invention that is, a polarizing plate in which a transparent protective film is bonded to at least one side of a polarizing element via a urea-based compound-containing adhesive layer, is a various image display device such as a liquid crystal display device or an organic EL display device.
  • the polarizing plate of the present invention has an interlayer filling structure in which a transparent member such as a front plate or a touch panel is arranged on the visual side of the image display device, and the image display panel and the transparent member are bonded by an adhesive layer or the like. It is preferably used in an image display device.
  • the image display cell examples include a liquid crystal cell and an organic EL cell.
  • the liquid crystal cell includes a reflective liquid crystal cell that uses external light, a transmissive liquid crystal cell that uses light from a light source such as a backlight, and a semi-transmissive semi-reflective type that uses both external light and light from a light source. Any of the liquid crystal cells may be used.
  • the image display device liquid crystal display device
  • the image display device has a polarizing plate arranged on the side opposite to the viewing side of the image display cell (liquid crystal cell), and further arranges the light source. Will be done.
  • the polarizing plate on the light source side and the liquid crystal cell are bonded to each other via an appropriate adhesive layer.
  • any type such as VA mode, IPS mode, TN mode, STN mode and bend orientation ( ⁇ type) can be used.
  • the organic EL cell a cell in which a transparent electrode, an organic light emitting layer, and a metal electrode are sequentially laminated on a transparent substrate to form a light emitting body (organic electroluminescence light emitting body) or the like is preferably used.
  • the organic light emitting layer is a laminate of various organic thin films, for example, a laminate of a hole injection layer made of a triphenylamine derivative or the like and a light emitting layer made of a fluorescent organic solid such as anthracene, or a laminate of these.
  • Various layer configurations can be adopted, such as a laminate of electron-injected layers composed of a light-emitting layer and a perylene derivative, or a laminate of hole-injected layers, light-emitting layers, and electron-injected layers.
  • An adhesive layer (adhesive sheet) is preferably used for bonding the image display cell and the polarizing plate.
  • An adhesive layer is preferably used for bonding the image display cell and the polarizing plate.
  • a method in which a polarizing plate with an adhesive layer having an adhesive layer attached to one surface of the polarizing plate is attached to an image display cell is preferable from the viewpoint of workability and the like.
  • the pressure-sensitive adhesive layer can be attached to the polarizing plate by an appropriate method.
  • a pressure-sensitive adhesive solution of about 10 to 40% by weight is prepared by dissolving or dispersing the base polymer or its composition in a solvent composed of a single substance or a mixture of appropriate solvents such as toluene and ethyl acetate.
  • a method of directly attaching it on a polarizing plate by an appropriate developing method such as a casting method or a coating method, or a method of forming an adhesive layer on a separator according to the above and transferring it to the polarizing plate, etc. can be mentioned.
  • the pressure-sensitive adhesive layer is described in paragraphs [0103] to [0143] of JP-A-2018-025765, and these pressure-sensitive adhesives can be used in the present invention.
  • front transparent member examples of the front transparent member arranged on the visual side of the image display cell include a front plate (window layer) and a touch panel.
  • a transparent plate having appropriate mechanical strength and thickness is used.
  • a transparent resin plate such as an acrylic resin or a polycarbonate resin, a glass plate, or the like is used.
  • a functional layer such as an antireflection layer may be laminated on the visible side of the transparent plate.
  • a hard coat layer may be laminated to increase the physical strength, or a low moisture permeability layer may be laminated to reduce the moisture permeability.
  • touch panel various touch panels such as a resistive film method, a capacitance method, an optical method, an ultrasonic method, and a glass plate or a transparent resin plate having a touch sensor function are used.
  • a capacitance type touch panel is used as the front transparent member, it is preferable to provide a front plate made of glass or a transparent resin plate on the visual side of the touch panel.
  • a pressure-sensitive adhesive or a UV-curable adhesive is preferably used for bonding the polarizing plate and the front transparent member.
  • the pressure-sensitive adhesive can be attached by an appropriate method.
  • the attachment method of the pressure-sensitive adhesive layer used for bonding the image display cell and the polarizing plate described above can be mentioned.
  • a dam material is provided so as to surround the peripheral edge on the image display panel in order to prevent the adhesive solution from spreading before curing, and a front transparent member is placed on the dam material.
  • a method of placing and injecting an adhesive solution is preferably used. After the injection of the adhesive solution, alignment and defoaming are performed as necessary, and then UV light is irradiated to perform curing.
  • an embodiment of the present invention having a urea-based compound-containing layer other than an adhesive layer containing at least one urea-based compound on at least one surface of the polarizing element will be described.
  • the technical elements constituting the present invention such as the [polarizing element] other than the [urea-based compound-containing layer] are common to the embodiment in which the urea-based compound-containing layer is an adhesive layer.
  • the polarizing plate contains at least one selected from urea, a urea derivative, thiourea and a thiourea derivative formed on at least one surface of a polyvinyl alcohol-based resin polarizing element formed by adsorbing and orienting iodine. It has a urea-based compound-containing layer (other than an adhesive layer).
  • the urea-based compound-containing layer preferably has at least one urea-based compound and a binder.
  • the binder include a polymer binder, a thermosetting binder, and an active energy ray-curable binder, and any of the binders can be preferably used in the present invention.
  • the thickness of the urea-based compound-containing layer is preferably 0.1 to 20 ⁇ m, more preferably 0.5 to 15 ⁇ m, and even more preferably 1 to 10 ⁇ m.
  • the urea-based compound-containing layer may be laminated directly on the polarizing element or may be laminated via another layer, but the direct lamination on the polarizing element suppresses the decrease in transmittance in a high temperature environment. It is preferable because it is easy to do.
  • the polarizing plate in this embodiment preferably has a transparent protective film on at least one surface of the polarizing element via an adhesive layer in terms of increasing the physical strength of the polarizing plate. At this time, the adhesive layer may or may not contain the urea compound, but it is more preferable that the adhesive layer contains the urea compound.
  • polarized light with a single-sided protective film As described in the description of the protective film in other embodiments, in recent years, in order to meet the demand for thinner polarizing plates, a polarizing plate having a protective film on only one side of the polarizing element (hereinafter, "polarized light with a single-sided protective film”). Also called “plate”) has been developed. Attempts have been made to laminate a cured layer on a surface of a polarizing element that does not have a protective film, for the purpose of increasing the physical strength in such a configuration. (For example, Japanese Patent Application Laid-Open No. 2011-221185)
  • the cured layer contains a urea compound.
  • a cured layer is formed from a curable composition containing an organic solvent, but paragraphs [0020] to [0042] of JP-A-2017-075986 describe the aqueous active energy ray-curable polymer composition. A method of forming such a hardened layer from a solution is described. Since many urea-based compounds are water-soluble, it is one of the preferred embodiments of the present invention to include a water-soluble urea-based compound in such a composition to form a urea-based compound-containing layer.
  • a polarizing plate of still another embodiment having a polarizing element prepared by applying a urea-based compound-containing solution to at least one surface of the polarizing element and drying it will be described.
  • This aspect is used for a polarizing plate for an interlayer filling structure, and is characterized by a polarizing element that suppresses a decrease in simple substance transmittance even when exposed to a high temperature environment for a long time.
  • a solution containing at least one selected from urea, a urea derivative, a thiourea and a thiourea derivative is contained on at least one surface of the polarizing element made of a stretched polyvinyl alcohol-based resin film in which iodine is adsorbed and oriented. After coating, it can be produced by drying this coating liquid.
  • the solvent of the urea-based compound-containing solution of the present invention is preferably water, an organic solvent, or a mixed solution thereof, and more preferably water or a mixed solvent of water and alcohol.
  • the solvent is a mixed solvent of water and alcohol
  • the alcohol is preferably either methanol or ethanol.
  • the urea-based compound the above-mentioned urea-based compound can be preferably used, but the urea-based compound is preferably water-soluble in that the urea-based compound is unlikely to precipitate on the surface of the polarizing element after drying.
  • urea-based compound solution 10 g of urea was added to 90 g of pure water to obtain a 10 wt% urea aqueous solution (solution 1). Similarly, according to Table 1, urea was replaced with the urea-based compound shown in Table 1, and the solvent was replaced with methanol from pure water as needed to prepare solutions 2 to 9.
  • urea, methylurea, ethylurea, 1,3-dimethylurea, tetramethylurea, phenylurea, thiourea, methylthiourea, and tetrahydro-2-pyrimidinone used above are all reagents of Tokyo Kasei Kogyo Co., Ltd. used.
  • Adhesive 1 for Polarizing Plate The PVA solution for adhesive, urea solution, pure water, and methanol prepared above are blended so as to have a PVA concentration of 3.0%, a methanol concentration of 20%, and a urea concentration of 0.3%, and an adhesive for polarizing plates. I got 1.
  • Adhesives 2 to 14 for Polarizing Plates Preparation of Adhesives 2 to 14 for Polarizing Plates
  • the PVA solution for adhesives, the urea-based compound solution shown in Table 1, pure water, and methanol are adjusted to the PVA concentration of 3.0%, the methanol concentration of 20%, and the urea-based compound concentration to the concentrations shown in Table 2.
  • Adhesives 2 to 14 for polarizing plates were obtained.
  • the polarizing plate adhesive 12 uses two types of urea compounds, methylurea and 1,3-dimethylurea, in combination, and the polarizing plate adhesive 14 does not contain a urea compound.
  • Polarizing plates 2 to 14 were produced in the same manner as the polarizing plate 1 except that the polarizing plate adhesive 1 was replaced with the polarizing plate adhesives 2 to 14.
  • the optical laminate 15 was produced in the same manner as the optical laminate 14 except that the pressure-sensitive adhesive layer was laminated on the optical laminate 14 on only one side.
  • the optical laminates 1 to 14 produced above are each cut into a size of 50 mm ⁇ 100 mm, and the surfaces of the first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer are each made of non-alkali glass [trade name “EAGLE XG”. , Corning Inc.] to prepare an evaluation sample. Further, the optical laminate 15 is cut into a size of 50 mm ⁇ 100 mm, and the surface of the first pressure-sensitive adhesive layer is bonded to non-alkali glass [trade name “EAGLE XG”, manufactured by Corning Inc.) for evaluation. A sample was prepared.
  • the transmittance does not decrease and the evaluation result is A.
  • the decrease in transmittance is 5% or less after 200 hours: A When the decrease in transmittance reached 5% or more in 150 to 200 hours: B When the decrease in transmittance reached 5% or more in 100 to 150 hours: C Those with a decrease in transmittance of 5% or more after 100 hours: D
  • the amount of the urea compound added in Table 3 will be described.
  • the amount of the urea compound added to the adhesive is preferably 0.1 to 400 parts by weight, more preferably 1 to 200 parts by weight, based on 100 parts by weight of PVA. It is more preferably up to 100 parts by weight. In this example, the PVA concentration is 3.0%.
  • the larger the amount of any urea compound added the smaller the change in simple substance transmittance after the high temperature durability test, and conversely, the smaller the amount of the added amount, the smaller the cross loss after the high temperature durability test. Is shown. All of the urea compounds described in the examples have an effect of a simple substance transmittance change of B or more after the high temperature durability test and a cross loss of ⁇ or more at the same time, and have excellent effects in both performances. ing.
  • the range of the amount of addition which shows preferable performance that is, performance of elemental transmittance change of B or more and cross loss of ⁇ or more at the same time differs depending on each compound.
  • the addition amount of the above compound also has an appropriate range within the above-mentioned preferable addition amount range.
  • the addition amount shown in Table 3 shows the value of the minimum addition amount at which the simple substance transmittance is evaluated A in each urea-based compound. Further, for urea and thiourea, the addition amount was gradually reduced from the minimum addition amount to be evaluated A, and the value of the addition amount from ⁇ to ⁇ was also shown (the change in the single transmittance at that time was B). ). In addition, for methylurea, the addition amount was gradually reduced from the minimum addition amount that was evaluated as A, and the result of the addition amount that the cross loss changed from ⁇ to ⁇ is also shown (the change in single transmittance at that time was B).
  • the polarizing plate of the present invention using an adhesive containing a urea compound reduces the transmittance of a single substance even when it is used in an image display device having an interlayer filling structure and when it is exposed to a high temperature environment for a long time. It can be deterred.
  • the one using a urea derivative or a thiourea derivative as opposed to the one using urea or thiourea is particularly good because there is no decrease in the single transmittance and no cross loss.
  • An adhesive containing two types of urea-based compounds is also one of the preferred embodiments of the present invention because it can suppress a decrease in elemental transmittance even when exposed to a high temperature environment for a long time.
  • Methylurea is added so that the solid content concentration of methylurea is 1% by weight based on the composition of the cured layer forming composition BLC-1 described in paragraphs [0075] to [0076] of JP-A-2017-075986.
  • pure water is added so that the total solid content concentration becomes 26% by weight, and after mixing, the urea-based compound-containing curable composition (UBLC-1) is passed through a filter having a pore size of 5 ⁇ m after being irradiated with ultrasonic waves. Prepared.
  • a polarizing plate with a single-sided protective film (polarizing plate 22) with a cured layer containing no urea compound was prepared with reference to the polarizing plate 1 described in paragraphs [0070] to [0080] of JP-A-2017-075986.
  • the polarizing plate 22 is similarly subjected to a polarizing plate with a single-sided protective film having a curing layer containing a urea compound (polarized light) except that the curing forming composition (BLC-1) is replaced with the curing forming composition (UBLC-1).
  • a plate 21) was produced.
  • An optical laminate 21 and an optical laminate 22 were obtained in the same manner as for the optical laminate 14 except that the polarizing plate 14 was replaced with the polarizing plate 21 and the polarizing plate 22, respectively. These samples were evaluated in the same manner as in the optical lamination 14, and the results obtained are shown in Table 4. The evaluation of the cloth coming off after high temperature durability was performed so that the transparent protective film surface was on the outside.
  • the polarizing plate of the present invention provided with a urea-based compound-containing layer on at least one surface of a polarizing element transmits a single substance even when used in an image display device having an interlayer filling configuration or when exposed to a high temperature environment for a long time. The decrease in rate can be suppressed.
  • a 0.5% solution of methylurea was prepared as a coating solution.
  • a 0.5% solution of methylurea was applied to one side of the polarizing element 1 produced above using a bar coater so that the wet application amount was 10 ⁇ m, and dried at 60 ° C. for 5 minutes to obtain a polarizing element 2.
  • pure water was applied to one side of the polarizing element produced above using a bar coater so that the wet coating amount was 10 ⁇ m, and dried at 60 ° C. for 5 minutes to obtain a polarizing element 3.
  • a polarizing plate 31 and a polarizing plate 32 were obtained in the same manner with respect to the polarizing plate 14, except that the polarizing element 1 was replaced with the polarizing element 2 and the polarizing element 3, respectively.
  • An optical laminate 31 and an optical laminate 32 were obtained in the same manner with respect to the optical laminate 14 except that the polarizing plate 14 was replaced with the polarizing plate 31 and the polarizing plate 32, respectively. These samples were evaluated in the same manner as in the optical lamination 14, and the results obtained are shown in Table 5.
  • the polarizing plate of the present invention which has a polarizing element prepared by applying a solution containing a urea compound to at least one surface of the polarizing element and drying it, has a high temperature even when used in an image display device having an interlayer filling configuration. Even when exposed to the environment for a long time, the decrease in single transmittance can be suppressed.

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Abstract

The purpose of the present invention is to provide: a polarizing plate that has a low decrease in transmittance in high-temperature environments and outstanding durability, even if used in an image display device with an interlayer filling structure; and a method for manufacturing the polarizing plate. Another purpose of the present invention is to provide an image display device which achieves durability with improved display characteristics in high-temperature environments. The present invention provides a polarizing plate characterized by comprising: a polyvinyl alcohol–based resin polarizing element formed by adsorbing and orienting iodine; a layer that contains a urea-based compound, formed on at least one side of the polarizing element and including at least one selected from urea, a urea derivative, thiourea, and a thiourea derivative; and a transparent protective film.

Description

偏光板及び偏光板の製造方法並びにその偏光板を用いた画像表示装置Polarizing plate, manufacturing method of polarizing plate, and image display device using the polarizing plate
　本発明は、偏光板およびその製造方法に関する。さらに、本発明は当該偏光板の一方の面が画像表示セルと貼り合せられ、他方の面がタッチパネルや前面板等の透明部材と貼り合せられた画像表示装置に関する。 The present invention relates to a polarizing plate and a method for producing the same. Further, the present invention relates to an image display device in which one surface of the polarizing plate is bonded to an image display cell and the other surface is bonded to a transparent member such as a touch panel or a front plate.
　液晶表示装置（ＬＣＤ）は、液晶テレビだけでなく、パソコン、携帯電話等のモバイル、カーナビ等の車載用途などで広く用いられている。通常、液晶表示装置は、液晶セルの両側に粘着剤で偏光板を貼合した液晶パネル部材を有し、バックライト部材からの光を液晶パネル部材で制御することにより表示が行われている。
また、有機ＥＬ表示装置も近年、液晶表示装置と同様に、テレビ、携帯電話等のモバイル、カーナビ等の車載用途で広く用いられて来ている。
有機ＥＬ表示装置では、外光が金属電極（陰極）で反射され鏡面のように視認されることを抑止するために、画像表示パネルの視認側表面に円偏光板（偏光素子とλ／４板を含む積層体、以下では単に偏光板ということがある。）が配置される場合がある。 Liquid crystal display devices (LCDs) are widely used not only in liquid crystal televisions, but also in mobile devices such as personal computers and mobile phones, and in-vehicle applications such as car navigation systems. Usually, a liquid crystal display device has a liquid crystal panel member in which polarizing plates are attached to both sides of a liquid crystal cell with an adhesive, and display is performed by controlling the light from the backlight member by the liquid crystal panel member.
Further, in recent years, organic EL display devices, like liquid crystal display devices, have been widely used in mobile applications such as televisions and mobile phones, and in-vehicle applications such as car navigation systems.
In the organic EL display device, in order to prevent external light from being reflected by the metal electrode (cathode) and visually recognized like a mirror surface, a circular polarizing plate (polarizing element and λ / 4 plate) is formed on the visible side surface of the image display panel. A laminate containing the above, which may be simply referred to as a polarizing plate below) may be arranged.
　偏光板は上記のように、液晶表示装置や有機ＥＬ表示装置の部材として、車に搭載される機会が増えて来ている。車載用の画像表示装置に用いられる偏光板は、それ以外のテレビや携帯電話等のモバイル用途に比較して、高温環境下に曝されることが多く、より高温での特性変化が小さいこと（高温耐久性）が求められる。
一方、外表面から衝撃による画像表示パネルの破損防止等を目的として、画像表示パネルの偏光板よりもさらに視認側に、透明樹脂板やガラス板等の前面板（「ウインドウ層」等とも称される。）を設ける構成が増えて来ている。また、タッチパネルを備える表示装置では、画像表示パネルの偏光板よりもさらに視認側にタッチパネルが設けられ、タッチパネルよりもさらに視認側に前面板を備える構成が広く採用されている。 As described above, polarizing plates are increasingly mounted on automobiles as members of liquid crystal display devices and organic EL display devices. Polarizing plates used in in-vehicle image display devices are often exposed to high-temperature environments and have less change in characteristics at higher temperatures than other mobile applications such as televisions and mobile phones. High temperature durability) is required.
On the other hand, for the purpose of preventing damage to the image display panel due to impact from the outer surface, a front plate such as a transparent resin plate or a glass plate (also referred to as a "window layer" or the like) is further visible side than the polarizing plate of the image display panel. The number of configurations that provide ()) is increasing. Further, in a display device provided with a touch panel, a configuration in which a touch panel is provided on the viewing side of the image display panel on the viewing side and a front plate is provided on the viewing side of the image display panel is widely adopted.
　このような構成において、画像表示パネルと前面板やタッチパネル等の透明部材との間に空気層が存在すると、空気層界面での光の反射による外光の映り込みが生じ、画面の視認性が低下する傾向がある。そのため、画像表示パネルの視認側表面に配置される偏光板と前透明部材との間の空間を、これらの材料と屈折率が近い材料で充填する構成（以下「層間充填構成」と称する場合がある）を採用する動きが広まっている。層間充填材としては、界面での反射による視認性の低下を抑止すると共に、各部材間を接着固定する目的で、粘着剤やＵＶ硬化型接着剤が用いられる（例えば特許文献１参照）。 In such a configuration, if an air layer exists between the image display panel and a transparent member such as a front plate or a touch panel, external light is reflected due to reflection of light at the interface of the air layer, and the visibility of the screen is improved. Tends to decline. Therefore, the space between the polarizing plate and the front transparent member arranged on the visible surface of the image display panel is filled with a material having a refractive index close to that of these materials (hereinafter, may be referred to as an "interlayer filling structure"). There is a widespread movement to adopt). As the interlayer filler, an adhesive or a UV curable adhesive is used for the purpose of suppressing deterioration of visibility due to reflection at the interface and adhesively fixing the members to each other (see, for example, Patent Document 1).
　上記の層間充填構成は、屋外で使用されることが多い携帯電話等のモバイル用途での採用が広がっている。また、近年の視認性に対する要求の高まりから、カーナビゲーション装置等の車載用途においても、画像表示パネル表面に前面板を配置し、パネルと前面板との間を粘着剤層等で層間充填された構成の採用が検討されている。
　しかし、このような構成を採用する場合、加熱耐久試験（９５℃で２００時間等）の結果、偏光板面内中央部に、透過率の著しい低下が見られること、その一方、偏光板単独では９５℃で１０００時間でも著しい透過率の低下は見られないことが報告されており、これらの結果から、高温環境における偏光板の透過率の著しい低下は、偏光板の一方の面が画像表示セルと貼り合せられ、他方の面がタッチパネルや前面板等の透明部材と貼り合せられている層間充填構成を採用する画像表示装置が高温環境に暴露された場合に特有の問題であることも報告されている（特許文献２）。 The above-mentioned interlayer filling configuration is widely adopted in mobile applications such as mobile phones, which are often used outdoors. Further, due to the increasing demand for visibility in recent years, even in in-vehicle applications such as car navigation devices, a front plate is arranged on the surface of an image display panel, and the space between the panel and the front plate is filled with an adhesive layer or the like. Adoption of the configuration is being considered.
However, when such a configuration is adopted, as a result of a heating durability test (200 hours at 95 ° C., etc.), a significant decrease in transmittance is observed in the central portion of the polarizing plate surface, while the polarizing plate alone is used. It has been reported that no significant decrease in transmittance is observed even at 95 ° C. for 1000 hours. From these results, it is reported that the significant decrease in the transmittance of the polarizing plate in a high temperature environment is caused by one surface of the polarizing plate being an image display cell. It has also been reported that this is a problem peculiar to an image display device that employs an interlayer filling configuration in which the other surface is bonded to a transparent member such as a touch panel or a front plate when exposed to a high temperature environment. (Patent Document 2).
　そして、上記特許文献２には層間充填構成で透過率が著しく低下した偏光板は、ラマン分光測定で１１００ｃｍ－１付近（＝Ｃ－Ｃ＝結合に由来）および１５００ｃｍ－１付近（－Ｃ＝Ｃ－結合に由来）にピークを有していることから、ポリエン構造（－Ｃ＝Ｃ）ｎ－を形成していると考え、偏光素子を構成するポリビニルアルコールが脱水によりポリエン化されて生じたものであると推定している（特許文献２、段落［００１２］）。
　また、本発明者らは、層間充填構成で高温耐久試験を行ったサンプルのラマン分光測定を行い、透過率の低下に応じて、１１００ｃｍ－１付近および１５００ｃｍ－１付近のピーク面積の和が増加していることを観察している。 In Patent Document 2, the polarizing plate having a significantly reduced transmittance due to the interlayer filling configuration is measured by Raman spectroscopy at around 1100 cm -1 (= CC = derived from bonding) and around 1500 cm -1 (-C = C). Since it has a peak (derived from the bond), it is considered that a polyene structure (-C = C) n -is formed, and the polyvinyl alcohol constituting the polarizing element is polyeneized by dehydration. (Patent Document 2, paragraph [0012]).
Further, the present inventors performed Raman spectroscopic measurement of samples subjected to high-temperature durability test at interlayer filling configuration, in accordance with the decrease in the transmittance, increase the sum of the peak area in the vicinity of 1100 cm -1 and around 1500 cm -1 I'm observing what I'm doing.
　特許文献２ではその問題の解決策として、偏光板の単位面積当たりの水分量を規定量以下とし、なおかつ偏光素子に隣接する透明保護フィルムの飽和吸水量を規定量以下とすることにより透過率の低下を抑制する方法を提案している。
　しかし、本発明者等の追試の結果、上記解決策の低下抑制効果は必ずしも十分なものではなく、さらに、パネル作製時に偏光板の水分を減少させるために、偏光板や偏光板を貼合したパネルの加熱が必要となり、パネルの生産性を低下させる問題が新たに生じることが分かった。 In Patent Document 2, as a solution to the problem, the amount of water per unit area of the polarizing plate is set to a specified amount or less, and the saturated water absorption amount of the transparent protective film adjacent to the polarizing element is set to a specified amount or less to increase the transmittance. We are proposing a method to suppress the decrease.
However, as a result of additional tests by the present inventors, the effect of suppressing the decrease of the above solution is not always sufficient, and further, a polarizing plate or a polarizing plate is attached in order to reduce the water content of the polarizing plate at the time of panel fabrication. It has been found that the panel needs to be heated, which causes a new problem of reducing the productivity of the panel.
特開平１１－１７４４１７号公報Japanese Unexamined Patent Publication No. 11-174417 特開２０１４－１０２３５３号公報Japanese Unexamined Patent Publication No. 2014-102353
　上記のような状況に鑑みて、本発明の課題、すなわち本発明が解決しようとする課題は、層間充填構成の画像表示装置に用いられた場合においても、高温環境下での透過率の低下が小さく、耐久性に優れる偏光板およびその製造方法を提供することである。更に本発明の別の目的は、高温環境下での表示特性が改善された耐久性を備えた画像表示装置を提供することである。 In view of the above situation, the problem of the present invention, that is, the problem to be solved by the present invention, is that even when the image display device has an interlayer filling configuration, the transmittance is lowered in a high temperature environment. It is an object of the present invention to provide a polarizing plate which is small and has excellent durability and a method for producing the same. Yet another object of the present invention is to provide a durable image display device having improved display characteristics in a high temperature environment.
　本発明者等は鋭意検討の結果、ポリビニルアルコール系樹脂層にヨウ素を吸着配向させてなる偏光素子の少なくとも一方の面に接着剤層を介して透明保護フィルムが設けられる構成に於いて、接着剤層に尿素、尿素誘導体、チオ尿素及びチオ尿素誘導体から選ばれる少なくとも一種（以降、尿素、尿素誘導体、チオ尿素及びチオ尿素誘導体を単に「尿素系化合物」とも称する。）を含有させることで、偏光板の一方の面が画像表示セルと貼り合せられ、他方の面がタッチパネルや前面板等の透明部材と貼り合せられている層間充填構成において、高温環境下での透過率の低下を抑止できることを見出した。 As a result of diligent studies, the present inventors have made an adhesive in a configuration in which a transparent protective film is provided on at least one surface of a polarizing element formed by adsorbing and orienting iodine on a polyvinyl alcohol-based resin layer via an adhesive layer. Polarization by incorporating at least one selected from urea, urea derivatives, thiourea and thiourea derivatives (hereinafter, urea, urea derivatives, thiourea and thiourea derivatives are also simply referred to as "urea-based compounds") in the layer. In an interlayer filling configuration in which one surface of a plate is bonded to an image display cell and the other surface is bonded to a transparent member such as a touch panel or a front plate, it is possible to suppress a decrease in permeability in a high temperature environment. I found it.
　更に検討の結果、上記偏光素子の少なくとも一方の面に尿素系化合物を少なくとも一種を含有する層（以降、「尿素系化合物含有層」とも称す。）を積層することで、その層が接着剤層以外であっても、第１の発明同様、層間充填構成において、高温環境下での透過率の低下を抑止できる効果があることを見出した。 As a result of further examination, by laminating a layer containing at least one urea-based compound (hereinafter, also referred to as "urea-based compound-containing layer") on at least one surface of the polarizing element, the layer becomes an adhesive layer. Other than the above, it has been found that, as in the first invention, the interlayer filling configuration has an effect of suppressing a decrease in transmittance in a high temperature environment.
　また、層間充填構成を採用した装置において、本発明の尿素系化合物の中では、尿素誘導体またはチオ尿素誘導体が優れた高温環境下での透過率低下抑制効果だけでなく、高温環境下での偏光度低下抑制（クロス抜け抑止）効果においても優れた性能を示すことも見出した。
　本発明者らは、このような新しく見出した事実に基づき、本発明を完成するに至った。 Further, in the apparatus adopting the interlayer filling configuration, among the urea compounds of the present invention, the urea derivative or the thiourea derivative not only has an excellent effect of suppressing a decrease in transmittance in a high temperature environment, but also polarizes in a high temperature environment. It was also found that it shows excellent performance in the effect of suppressing the decrease in degree (suppressing cross omission).
The present inventors have completed the present invention based on such newly found facts.
　本発明が解決しようとする課題は、下記の手段により解決することができる。
（１）ヨウ素を吸着配向させてなるポリビニルアルコール系樹脂偏光素子、
　前記偏光素子の少なくとも一方の面に形成された
　尿素、尿素誘導体、チオ尿素及びチオ尿素誘導体から選ばれる少なくとも一種を含有する尿素系化合物含有層、及び
　透明保護フィルム
　を有することを特徴とする偏光板。
（２）前記尿素系化合物含有層が接着剤層であり、前記透明保護フィルムが該接着剤層を介して貼合されていることを特徴とする（１）に記載の偏光板。
（３）前記接着剤層が、更にポリビニルアルコール系樹脂を含有することを特徴とする（２）に記載の偏光板。
（４）前記接着剤層に含有される尿素系化合物の合計含有量が、ポリビニルアルコール系樹脂１００重量部に対し、１重量部以上４００重量部以下であることを特徴とする（３）に記載の偏光板。 The problem to be solved by the present invention can be solved by the following means.
(1) A polyvinyl alcohol-based resin polarizing element in which iodine is adsorbed and oriented.
A polarizing plate having a urea-based compound-containing layer containing at least one selected from urea, a urea derivative, a thiourea and a thiourea derivative, and a transparent protective film formed on at least one surface of the polarizing element. ..
(2) The polarizing plate according to (1), wherein the urea-based compound-containing layer is an adhesive layer, and the transparent protective film is bonded via the adhesive layer.
(3) The polarizing plate according to (2), wherein the adhesive layer further contains a polyvinyl alcohol-based resin.
(4) Described in (3), the total content of the urea-based compound contained in the adhesive layer is 1 part by weight or more and 400 parts by weight or less with respect to 100 parts by weight of the polyvinyl alcohol-based resin. Polarizing plate.
（５）前記尿素系化合物が、尿素誘導体及び／又はチオ尿素誘導体であることを特徴とする（１）～（４）のいずれかに記載の偏光板。
（６）前記接着剤層の厚みが、０．０１～７μｍであることを特徴とする（２）～（５）のいずれかに記載の偏光板。
（７）前記尿素系化合物含有層が接着剤層以外の樹脂層であることを特徴とする（１）に記載の偏光板。
（８）前記偏光板が、層間充填構成を有する画像表示装置に用いられるものであることを特徴とする（１）～（７）のいずれかに記載の偏光板。 (5) The polarizing plate according to any one of (1) to (4), wherein the urea compound is a urea derivative and / or a thiourea derivative.
(6) The polarizing plate according to any one of (2) to (5), wherein the thickness of the adhesive layer is 0.01 to 7 μm.
(7) The polarizing plate according to (1), wherein the urea-based compound-containing layer is a resin layer other than the adhesive layer.
(8) The polarizing plate according to any one of (1) to (7), wherein the polarizing plate is used in an image display device having an interlayer filling structure.
（９）偏光素子の少なくとも一方の面に透明保護フィルムが貼合された偏光板を製造する方法であって、
　ヨウ素が吸着配向された延伸ポリビニルアルコール系樹脂フィルムからなる偏光素子の少なくとも一方の面に、
　ポリビニルアルコール系樹脂及び
　尿素、尿素誘導体、チオ尿素及びチオ尿素誘導体から選ばれる少なくとも１種を含有する接着剤組成物を用いて接着剤層を形成する工程、
　上記接着剤層を形成する工程と同時又は形成後、該接着剤層を介し透明保護フィルムを貼合する工程を含むことを特徴とする偏光板の製造方法。 (9) A method for manufacturing a polarizing plate in which a transparent protective film is bonded to at least one surface of a polarizing element.
On at least one surface of a polarizing element made of a stretched polyvinyl alcohol-based resin film in which iodine is adsorbed and oriented,
A step of forming an adhesive layer using an adhesive composition containing a polyvinyl alcohol-based resin and at least one selected from urea, a urea derivative, thiourea and a thiourea derivative.
A method for producing a polarizing plate, which comprises a step of laminating a transparent protective film through the adhesive layer at the same time as or after the step of forming the adhesive layer.
（１０）請求項１～９のいずれかに記載の偏光板が画像表示セルの視認側表面に粘着剤層を介して貼り合わされている画像表示パネル、及び
　前記画像表示パネルの視認側偏光板面に粘着剤層を介して貼り合わされた透明部材、
を有することを特徴とする画像表示装置。
（１１）前記透明部材が、ガラス板または透明樹脂板であることを特徴とする（１０）に記載の画像表示装置。
（１２）前記透明部材が、タッチパネルであることを特徴とする（１０）に記載の画像表示装置。 (10) An image display panel in which the polarizing plate according to any one of claims 1 to 9 is bonded to the viewing side surface of the image display cell via an adhesive layer, and a viewing side polarizing plate surface of the image display panel. Transparent member, bonded to the surface via an adhesive layer,
An image display device characterized by having.
(11) The image display device according to (10), wherein the transparent member is a glass plate or a transparent resin plate.
(12) The image display device according to (10), wherein the transparent member is a touch panel.
　本発明により、層間充填構成の画像表示装置に用いられた場合においても、高温環境下での透過率の低下が小さく、高温耐久性に優れる偏光板およびその製造方法の提供することが可能となり、さらに、本発明の偏光板を用いることで高温環境下での透過率低下が抑制された表示装置を提供することが可能となる。 INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide a polarizing plate having a small decrease in transmittance in a high temperature environment and excellent high temperature durability even when used in an image display device having an interlayer filling configuration, and a method for manufacturing the same. Further, by using the polarizing plate of the present invention, it is possible to provide a display device in which a decrease in transmittance is suppressed in a high temperature environment.
　本発明における１つの態様では、ポリビニルアルコール系樹脂層にヨウ素を吸着配向させてなる偏光素子の少なくとも一方の面に接着剤層を介して透明保護フィルムが設けられる構成に於いて、接着剤層に尿素、尿素誘導体、チオ尿素及びチオ尿素誘導体から選ばれる少なくとも一種を含有する。 In one aspect of the present invention, in a configuration in which a transparent protective film is provided on at least one surface of a polarizing element formed by adsorbing and orienting iodine on a polyvinyl alcohol-based resin layer via an adhesive layer, the adhesive layer is provided. It contains at least one selected from urea, urea derivatives, thiourea and thiourea derivatives.
　以下、本発明を構成する技術要素について説明するが、尿素系化合物含有層以外は他の態様（尿素系化合物含有層が接着剤層以外の層である態様）においても共通である。
［偏光素子］
　本発明のポリビニルアルコール（以降ＰＶＡとも称す）系樹脂層にヨウ素を吸着配向させてなる偏光素子としては、周知の偏光素子を用いることができる。このような偏光素子は、一般にＰＶＡ系樹脂フィルムを用い、このＰＶＡ系樹脂フィルムをヨウ素で染色し、一軸延伸することによって形成される。 Hereinafter, the technical elements constituting the present invention will be described, but they are also common to other embodiments (a mode in which the urea compound-containing layer is a layer other than the adhesive layer) other than the urea compound-containing layer.
[Polarizing element]
A well-known polarizing element can be used as the polarizing element in which iodine is adsorbed and oriented on the polyvinyl alcohol (hereinafter, also referred to as PVA) -based resin layer of the present invention. Such a polarizing element is generally formed by using a PVA-based resin film, dyeing the PVA-based resin film with iodine, and uniaxially stretching the film.
　ＰＶＡ系樹脂は、前述のように、一般に、ポリ酢酸ビニル系樹脂を鹸化して得られるものを用いる。鹸化度は、約８５モル％以上、好ましくは約９０モル％以上、より好ましくは約９９モル％～１００モル％である。ポリ酢酸ビニル系樹脂としては、酢酸ビニルの単独重合体であるポリ酢酸ビニルのほか、酢酸ビニルとこれに共重合可能な他の単量体との共重合体、例えば、エチレン－酢酸ビニル共重合体などが挙げられる。共重合可能な他の単量体としては、例えば不飽和カルボン酸類、オレフィン類、ビニルエーテル類、不飽和スルホン酸類などが挙げられる。ＰＶＡ系樹脂の重合度としては、１０００～１００００、好ましくは１５００～５０００である。このＰＶＡ系樹脂は変性されていてもよく、たとえば、アルデヒド類で変性されたポリビニルホルマール、ポリビニルアセタール、ポリビニルブチラールなどでもよい。 As the PVA-based resin, as described above, generally, one obtained by saponifying a polyvinyl acetate-based resin is used. The degree of saponification is about 85 mol% or more, preferably about 90 mol% or more, and more preferably about 99 mol% to 100 mol%. Examples of the polyvinyl acetate-based resin include polyvinyl acetate, which is a homopolymer of vinyl acetate, and a copolymer of vinyl acetate and another monomer copolymerizable therewith, for example, ethylene-vinyl acetate copolymer weight. Coalescence etc. can be mentioned. Examples of other copolymerizable monomers include unsaturated carboxylic acids, olefins, vinyl ethers, unsaturated sulfonic acids and the like. The degree of polymerization of the PVA-based resin is 1000 to 10000, preferably 1500 to 5000. This PVA-based resin may be modified, and may be, for example, polyvinyl formal, polyvinyl acetal, polyvinyl butyral, etc. modified with aldehydes.
　偏光素子の製造方法は特に限定されないが、予めロール状に巻かれたポリビニルアルコール系樹脂フィルムを送り出して延伸、染色、架橋などを行って作製する方法やポリビニルアルコール系樹脂と延伸用樹脂基材との積層体を作製し、積層体の状態で延伸を行う工程を含む方法が典型的である。本発明ではこれら、何れの方法も用いることができる。
これらの偏光素子の製造方法については特開２０１４－４８４９７号公報の段落［０１０９］～［０１２８］に記載されており、本発明ではこれらの方法を用いることができる。また、本発明の偏光素子の厚みは３～３５μｍが好ましく、４～３０μｍがより好ましく、５～２５μｍが更に好ましい。 The method for manufacturing the polarizing element is not particularly limited, but a method of feeding out a polyvinyl alcohol-based resin film wound in a roll shape in advance and performing stretching, dyeing, cross-linking, etc., or a polyvinyl alcohol-based resin and a resin base material for stretching. A method including a step of producing a laminated body of the above and stretching in the state of the laminated body is typical. In the present invention, any of these methods can be used.
Methods for manufacturing these polarizing elements are described in paragraphs [0109] to [0128] of JP2014-48497A, and these methods can be used in the present invention. The thickness of the polarizing element of the present invention is preferably 3 to 35 μm, more preferably 4 to 30 μm, and even more preferably 5 to 25 μm.
［尿素系化合物含有層］
　本発明の偏光板はヨウ素を吸着配向させてなるポリビニルアルコール系樹脂偏光素子の少なくとも一方の面に形成された尿素、尿素誘導体、チオ尿素及びチオ尿素誘導体から選ばれる少なくとも一種を含有する尿素系化合物含有層を有する。
　本発明において、尿素系化合物含有層は接着剤層である必要はないが、生産性の観点で接着剤層が尿素系化合物を含有することが好ましい。接着剤層は以下の接着剤によって形成される。
尚、尿素系化合物含有層が接着剤層以外の構成については後述する。 [Urea compound-containing layer]
The polarizing plate of the present invention is a urea-based compound containing at least one selected from urea, a urea derivative, a thiourea and a thiourea derivative formed on at least one surface of a polyvinyl alcohol-based resin polarizing element formed by adsorbing and orienting iodine. It has a containing layer.
In the present invention, the urea-based compound-containing layer does not have to be an adhesive layer, but it is preferable that the adhesive layer contains a urea-based compound from the viewpoint of productivity. The adhesive layer is formed by the following adhesive.
The structure of the urea-based compound-containing layer other than the adhesive layer will be described later.
［接着剤］
　偏光素子に保護フィルムを貼合するための接着剤は、任意の適切な接着剤を用いることができる。具体的には、接着剤としては、水系接着剤、溶剤系接着剤、活性エネルギー線硬化型などを用いることができるが、水系接着剤であることが好ましい。
　接着剤層が尿素系化合物含有層である場合、接着剤は尿素、尿素誘導体、チオ尿素及びチオ尿素誘導体から選ばれる少なくとも一種を含有する。
上記接着剤の塗布時の厚みは、任意の適切な値に設定され得る。例えば、硬化後または加熱（乾燥）後に、所望の厚みを有する接着剤層が得られるように設定する。接着剤層の厚みは、好ましくは０．０１μｍ～７μｍであり、より好ましくは０．０１μｍ～５μｍであり、さらに好ましくは０．０１μｍ～２μｍであり、最も好ましくは０．０１μｍ～１μｍである。 [adhesive]
Any suitable adhesive can be used as the adhesive for adhering the protective film to the polarizing element. Specifically, as the adhesive, a water-based adhesive, a solvent-based adhesive, an active energy ray-curable type, or the like can be used, but a water-based adhesive is preferable.
When the adhesive layer is a urea-based compound-containing layer, the adhesive contains at least one selected from urea, urea derivatives, thiourea and thiourea derivatives.
The thickness of the adhesive when applied can be set to any appropriate value. For example, after curing or heating (drying), an adhesive layer having a desired thickness is set so as to be obtained. The thickness of the adhesive layer is preferably 0.01 μm to 7 μm, more preferably 0.01 μm to 5 μm, still more preferably 0.01 μm to 2 μm, and most preferably 0.01 μm to 1 μm.
（水系接着剤）
　また、上記水系接着剤としては、任意の適切な水系接着剤が採用され得る。中でも、ＰＶＡ系樹脂を含む水系接着剤（ＰＶＡ系接着剤）が好ましく用いられる。水系接着剤に含まれるＰＶＡ系樹脂の平均重合度は、接着性の点から、好ましくは１００～５５００程度、さらに好ましくは１０００～４５００である。平均鹸化度は、接着性の点から、好ましくは８５モル％～１００モル％程度であり、さらに好ましくは９０モル％～１００モル％である。 (Water-based adhesive)
Further, as the water-based adhesive, any suitable water-based adhesive can be adopted. Of these, a water-based adhesive containing a PVA-based resin (PVA-based adhesive) is preferably used. The average degree of polymerization of the PVA-based resin contained in the water-based adhesive is preferably about 100 to 5500, more preferably 1000 to 4500, from the viewpoint of adhesiveness. The average saponification degree is preferably about 85 mol% to 100 mol%, and more preferably 90 mol% to 100 mol% from the viewpoint of adhesiveness.
　上記水系接着剤に含まれるＰＶＡ系樹脂としては、アセトアセチル基を含有するものが好ましく、その理由は、ＰＶＡ系樹脂層と保護フィルムとの密着性に優れ、耐久性に優れているからである。アセトアセチル基含有ＰＶＡ系樹脂は、例えば、ＰＶＡ系樹脂とジケテンとを任意の方法で反応させることにより得られる。アセトアセチル基含有ＰＶＡ系樹脂のアセトアセチル基変性度は、代表的には０．１モル％以上であり、好ましくは０．１モル％～２０モル％程度である。
　上記水系接着剤の樹脂濃度は、好ましくは０．１重量％～１５重量％であり、さらに好ましくは０．５重量％～１０重量％である。 The PVA-based resin contained in the water-based adhesive is preferably one containing an acetoacetyl group, because the PVA-based resin layer has excellent adhesion to the protective film and has excellent durability. .. The acetoacetyl group-containing PVA-based resin can be obtained, for example, by reacting the PVA-based resin with diketene by an arbitrary method. The degree of acetoacetyl group modification of the acetoacetyl group-containing PVA resin is typically 0.1 mol% or more, preferably about 0.1 mol% to 20 mol%.
The resin concentration of the water-based adhesive is preferably 0.1% by weight to 15% by weight, more preferably 0.5% by weight to 10% by weight.
（架橋剤、溶剤）
　本発明で好ましく用いることが出来る水溶性ＰＶＡ系接着剤は上記のＰＶＡ系樹脂、尿素系化合物の他に必要に応じて架橋剤を含有させることもできる。架橋剤としては公知の架橋剤を用いることができる。例えば、水溶性エポキシ化合物、ジアルデヒド、イソシアネートなどが挙げられる。 (Crosslinking agent, solvent)
The water-soluble PVA-based adhesive that can be preferably used in the present invention may contain a cross-linking agent in addition to the above-mentioned PVA-based resin and urea-based compound, if necessary. As the cross-linking agent, a known cross-linking agent can be used. For example, water-soluble epoxy compounds, dialdehydes, isocyanates and the like can be mentioned.
　ＰＶＡ系樹脂がアセトアセチル基含有ＰＶＡ系樹脂である場合は、架橋剤としてグリオキサール、グリオキシル酸塩、メチロールメラミンのうちの何れかであることが好ましく、グリオキサール、グリオキシル酸塩の何れかであることが好ましく、グリオキサールであることが特に好ましい。 When the PVA-based resin is an acetoacetyl group-containing PVA-based resin, the cross-linking agent is preferably any one of glyoxal, glyoxyphosphate, and methylolmelamine, and may be glyoxal or glyoxalate. Glyoxal is preferable, and glyoxal is particularly preferable.
　また、本発明の水溶性ＰＶＡ系接着剤は有機溶剤を含有していても構わない。その場合、水と混和性を有する点でアルコール類が好ましく、アルコール類の中でもメタノールまたはエタノールであることがより好ましい。
また、本発明では、尿素誘導体の一部は水に対する溶解度が低い反面、アルコールに対する溶解度は十分なものがある。その場合は、アルコールに溶解し、尿素誘導体のアルコール溶液を調製した後、尿素誘導体のアルコール溶液をＰＶＡ水溶液に添加し、接着剤を調製することも好ましい態様の一つである。 Further, the water-soluble PVA-based adhesive of the present invention may contain an organic solvent. In that case, alcohols are preferable because they are miscible with water, and methanol or ethanol is more preferable among the alcohols.
Further, in the present invention, some urea derivatives have low solubility in water, but some have sufficient solubility in alcohol. In that case, one of the preferred embodiments is to dissolve in alcohol to prepare an alcohol solution of the urea derivative, and then add the alcohol solution of the urea derivative to the PVA aqueous solution to prepare an adhesive.
（活性エネルギー線硬化型接着剤）
　上記活性エネルギー線硬化型接着剤としては、活性エネルギー線の照射によって硬化し得る接着剤であれば、任意の適切な接着剤が用いられ得る。活性エネルギー線硬化型接着剤としては、例えば、紫外線硬化型接着剤、電子線硬化型接着剤等が挙げられる。活性エネルギー線硬化型接着剤の硬化型の具体例としては、ラジカル硬化型、カチオン硬化型、アニオン硬化型、これらの組み合わせ（例えば、ラジカル硬化型とカチオン硬化型のハイブリッド）が挙げられる。 (Active energy ray-curable adhesive)
As the active energy ray-curable adhesive, any suitable adhesive can be used as long as it is an adhesive that can be cured by irradiation with active energy rays. Examples of the active energy ray-curable adhesive include an ultraviolet curable adhesive and an electron beam-curable adhesive. Specific examples of the curing type of the active energy ray-curing adhesive include a radical curing type, a cation curing type, an anion curing type, and a combination thereof (for example, a hybrid of a radical curing type and a cation curing type).
　上記活性エネルギー線硬化型接着剤としては、例えば、硬化成分として（メタ）アクリレート基や（メタ）アクリルアミド基などのラジカル重合性基を有する化合物（例えば、モノマーおよび／またはオリゴマー）を含有する接着剤が挙げられる。
　上記活性エネルギー線硬化型接着剤およびその硬化方法の具体例は、例えば、特開２０１２－１４４６９０号公報に記載されている。 The active energy ray-curable adhesive is, for example, an adhesive containing a compound having a radically polymerizable group such as a (meth) acrylate group or a (meth) acrylamide group (for example, a monomer and / or an oligomer) as a curing component. Can be mentioned.
Specific examples of the active energy ray-curable adhesive and a curing method thereof are described in, for example, Japanese Patent Application Laid-Open No. 2012-144690.
［尿素系化合物］
　本発明では接着剤層に、尿素、尿素誘導体、チオ尿素及びチオ尿素誘導体から選ばれる少なくとも１種を含有する。
　接着剤層に尿素系化合物を含有させる方法としては、上記の接着剤に尿素系化合物を含有させることが好ましい。尚、接着剤から乾燥工程などを経て接着剤層を形成する過程で、尿素系化合物の一部が接着剤層から偏光素子などに移動していても構わない。
尿素系化合物には水溶性のものと難水溶性のものがあるが、どちらの尿素系化合物も本発明では使用することができる。難水溶性尿素系化合物を水溶性接着剤に用いる場合は、接着剤層を形成後、ヘイズ上昇などが起きないように分散方法を工夫することが好ましい。 [Urea compound]
In the present invention, the adhesive layer contains at least one selected from urea, urea derivatives, thiourea and thiourea derivatives.
As a method for incorporating the urea-based compound in the adhesive layer, it is preferable to include the urea-based compound in the above-mentioned adhesive. In the process of forming the adhesive layer from the adhesive through a drying step or the like, a part of the urea-based compound may be transferred from the adhesive layer to the polarizing element or the like.
There are water-soluble and poorly water-soluble urea compounds, and both urea compounds can be used in the present invention. When a poorly water-soluble urea compound is used as a water-soluble adhesive, it is preferable to devise a dispersion method so that haze does not increase after the adhesive layer is formed.
　接着剤がＰＶＡ系樹脂を含有する水系接着剤の場合、尿素系化合物の添加量は、ＰＶＡ系樹脂１００重量部に対し、０．１～４００重量部であることが好ましく、１～２００重量部であることがより好ましく、３～１００重量部であることが更に好ましい。 When the adhesive is a water-based adhesive containing a PVA-based resin, the amount of the urea-based compound added is preferably 0.1 to 400 parts by weight with respect to 100 parts by weight of the PVA-based resin, and 1 to 200 parts by weight. It is more preferable that the amount is 3 to 100 parts by weight.
（尿素または尿素誘導体）
　本発明において、尿素誘導体とは尿素の一部が置換基により置換された分子構造を有する化合物であることを意味する。尿素誘導体としては、尿素分子の４つの水素原子の少なくとも１つが、置換基に置換された化合物であることが好ましい。
この場合、置換基に特に制限はないが、炭素原子、水素原子および酸素原子よりなる置換基であることが好ましい。 (Urea or urea derivative)
In the present invention, the urea derivative means a compound having a molecular structure in which a part of urea is substituted with a substituent. As the urea derivative, it is preferable that at least one of the four hydrogen atoms of the urea molecule is a compound substituted with a substituent.
In this case, the substituent is not particularly limited, but is preferably a substituent composed of a carbon atom, a hydrogen atom and an oxygen atom.
　尿素誘導体の具体例として、１置換尿素として、メチル尿素、エチル尿素、プロピル尿素、ブチル尿素、イソブチル尿素、Ｎ－オクタデシル尿素、２－ヒドロキシエチル尿素、ヒドロキシ尿素、アセチル尿素、アリル尿素、２－プロピニル尿素、シクロヘキシル尿素、フェニル尿素、３－ヒドロキシフェニル尿素、（４－メトキシフェニル）尿素、ベンジル尿素、ベンゾイル尿素、ｏ－トリル尿素、ｐ－トリル尿素が挙げられる。
２置換尿素として、１，１－ジメチル尿素、１，３－ジメチル尿素、１，１－ジエチル尿素、１，３－ジエチル尿素、１，３－ビス（ヒドロキシメチル）尿素、１，３－ｔｅｒｔ－ブチル尿素、１，３－ジシクロヘキシル尿素、１，３－ジフェニル尿素、１，３－ビス（４－メトキシフェニル）尿素、１－アセチル－３－メチル尿素、２－イミダゾリジノン（エチレン尿素）、テトラヒドロ－２－ピリミジノン（プロピレン尿素）が挙げられる。
４置換尿素として、テトラメチル尿素、１，１，３，３－テトラエチル尿素、１，１，３，３－テトラブチル尿素、１，３－ジメトキシ－１，３－ジメチル尿素、１，３－ジメチル－２－イミダゾリジノン、１，３－ジメチル－３，４，５，６－テトラヒドロ－２（１Ｈ）－ピリミジノンが挙げられる。 Specific examples of urea derivatives include methyl urea, ethyl urea, propyl urea, butyl urea, isobutyl urea, N-octadecyl urea, 2-hydroxyethyl urea, hydroxyurea, acetylurea, allylurea, and 2-propynyl as monosubstituted ureas. Examples thereof include urea, cyclohexyl urea, phenyl urea, 3-hydroxyphenyl urea, (4-methoxyphenyl) urea, benzyl urea, benzoyl urea, o-tolyl urea and p-tolyl urea.
As the disubstituted urea, 1,1-dimethylurea, 1,3-dimethylurea, 1,1-diethylurea, 1,3-diethylurea, 1,3-bis (hydroxymethyl) urea, 1,3-tert- Butylurea, 1,3-dicyclohexylurea, 1,3-diphenylurea, 1,3-bis (4-methoxyphenyl) urea, 1-acetyl-3-methylurea, 2-imidazolidinone (ethyleneurea), tetrahydro -2-Pyrimidinone (propylene urea) can be mentioned.
As tetra-substituted urea, tetramethylurea, 1,1,3,3-tetraethylurea, 1,1,3,3-tetrabutylurea, 1,3-dimethoxy-1,3-dimethylurea, 1,3-dimethyl- Examples thereof include 2-imidazolidinone and 1,3-dimethyl-3,4,5,6-tetrahydro-2 (1H) -pyrimidinone.
（チオ尿素またはチオ尿素誘導体）
　本発明において、チオ尿素誘導体とはチオ尿素の一部が置換基により置換された分子構造を有する化合物であることを意味する。チオ尿素誘導体としては、チオ尿素分子の４つの水素原子の少なくとも１つが、置換基に置換された化合物であることが好ましい。
この場合、置換基に特に制限はないが、炭素原子、水素原子および酸素原子よりなる置換基であることが好ましい。 (Thiourea or thiourea derivative)
In the present invention, the thiourea derivative means a compound having a molecular structure in which a part of thiourea is substituted with a substituent. The thiourea derivative is preferably a compound in which at least one of the four hydrogen atoms of the thiourea molecule is substituted with a substituent.
In this case, the substituent is not particularly limited, but is preferably a substituent composed of a carbon atom, a hydrogen atom and an oxygen atom.
　チオ尿素誘導体の具体例として、１置換チオ尿素として、Ｎ－メチルチオ尿素、エチルチオ尿素、プロピルチオ尿素、イソプロピルチオ尿素、１－ブチルチオ尿素、シクロヘキシルチオ尿素、Ｎ－アセチルチオ尿素、Ｎ－アリルチオ尿素、（２－メトキシエチル）チオ尿素、Ｎ－フェニルチオ尿素、（４－メトキシフェニル）チオ尿素、Ｎ－（２－メトキシフェニル）チオ尿素、Ｎ－（１－ナフチル）チオ尿素、（２－ピリジル）チオ尿素、ｏ－トリルチオ尿素、ｐ－トリルチオ尿素が挙げられる。
　２置換チオ尿素として、１，１－ジメチルチオ尿素、１，３－ジメチルチオ尿素、１，１－ジエチルチオ尿素、１，３－ジエチルチオ尿素、１，３－ジブチルチオ尿素、１，３－ジイソプロピルチオ尿素、１，３－ジシクロヘキシルチオ尿素、Ｎ，Ｎ－ジフェニルチオ尿素、Ｎ，Ｎ’－ジフェニルチオ尿素、１，３－ジ（ｏ－トリル）チオ尿素、１，３－ジ（ｐ－トリル）チオ尿素、１－ベンジル－３－フェニルチオ尿素、１－メチル－３－フェニルチオ尿素、Ｎ－アリル－Ｎ’－（２－ヒドロキシエチル）チオ尿素、エチレンチオ尿素が挙げられる。
　３置換チオ尿素として、トリメチルチオ尿素が挙げられ、４置換チオ尿素として、テトラメチルチオ尿素、１，１，３，３－テトラエチルチオ尿素が挙げられる。 Specific examples of the thiourea derivative include N-methylthiourea, ethylthiourea, propylthiourea, isopropylthiourea, 1-butylthiourea, cyclohexylthiourea, N-acetylthiourea, and N-allylthiourea, (2) as monosubstituted thioureas. -Methoxyethyl) thiourea, N-phenylthiourea, (4-methoxyphenyl) thiourea, N- (2-methoxyphenyl) thiourea, N- (1-naphthyl) thiourea, (2-pyridyl) thiourea, Examples thereof include o-tolylthiourea and p-tolylthiourea.
As the disubstituted thiourea, 1,1-dimethylthiourea, 1,3-dimethylthiourea, 1,1-diethylthiourea, 1,3-diethylthiourea, 1,3-dibutylthiourea, 1,3-diisopropylthiourea, 1 , 3-Dicyclohexylthiourea, N, N-diphenylthiourea, N, N'-diphenylthiourea, 1,3-di (o-tolyl) thiourea, 1,3-di (p-tolyl) thiourea, Examples thereof include 1-benzyl-3-phenylthiourea, 1-methyl-3-phenylthiourea, N-allyl-N'-(2-hydroxyethyl) thiourea and ethylenethiourea.
Examples of the 3-substituted thiourea include trimethylthiourea, and examples of the 4-substituted thiourea include tetramethylthiourea and 1,1,3,3-tetraethylthiourea.
　上記化合物の中では、層間充填構成の画像表示装置に用いた時に、高温環境下での透過率の低下が少なく、且つ偏光度の低下が少ない点で、尿素誘導体またはチオ尿素誘導体が好ましく、尿素誘導体がより好ましい。尿素誘導体の中でも、１置換尿素または２置換尿素であることが好ましく、１置換尿素であることがより好ましい。２置換尿素には１，１－置換尿素と１，３－置換尿素があるが、１，３－置換尿素がより好ましい。 Among the above compounds, a urea derivative or a thiourea derivative is preferable because, when used in an image display device having an interlayer filling structure, the decrease in transmittance is small and the decrease in polarization degree is small in a high temperature environment. Derivatives are more preferred. Among the urea derivatives, mono-substituted urea or di-substituted urea is preferable, and mono-substituted urea is more preferable. The di-substituted urea includes 1,1-substituted urea and 1,3-substituted urea, but 1,3-substituted urea is more preferable.
［透明保護フィルム］
　本発明において用いられる透明保護フィルム（以降、単に「保護フィルム」とも称す。）は、偏光素子の少なくとも片面側に本発明の尿素系化合物含有接着剤層を介して貼り合わされる。この透明保護フィルムは偏光素子の片面又は両面に貼り合わされるが、両面に貼り合わされていることがより好ましい。
また、偏光素子の両面に接着剤層を介して保護フィルムが貼り合わされている構成に於いて、偏光素子両面の接着剤層の内、片面の接着剤層のみが本発明の尿素系化合物含有接着剤層であっても構わないが、両面の接着剤層が共に本発明の尿素系化合物含有接着剤層であることがより好ましい。 [Transparent protective film]
The transparent protective film used in the present invention (hereinafter, also simply referred to as “protective film”) is attached to at least one side of the polarizing element via the urea-based compound-containing adhesive layer of the present invention. This transparent protective film is attached to one side or both sides of the polarizing element, but it is more preferable that the transparent protective film is attached to both sides.
Further, in the configuration in which the protective film is bonded to both sides of the polarizing element via the adhesive layer, only one of the adhesive layers on both sides of the polarizing element is the urea-based compound-containing adhesive of the present invention. Although it may be an agent layer, it is more preferable that both adhesive layers are the urea-based compound-containing adhesive layer of the present invention.
　近年、偏光板の薄型化の要請に応えるために、偏光素子の片面にのみ保護フィルムを有する偏光板が開発されている。この構成に於いても、本発明の尿素系化合物含有接着剤層を介して保護フィルムを積層することが好ましい。
　偏光素子の片面にのみ保護フィルムを有する偏光板の作製方法として、最初に両面に接着剤層を介して保護フィルムを貼合した偏光板を作製した後に、一方の保護フィルムを剥離する方法が考えられるが、このような製造方法が用いられる場合、どちらか一方の接着剤層のみが本発明の接着剤層であっても構わないが、本発明の尿素系化合物含有接着剤層が偏光素子の両面に用いられることがより好ましい。
　また、本発明の尿素系化合物含有接着剤層が偏光素子の片面のみに用いられる場合は、剥離しないフィルム側の接着剤層が本発明の尿素系化合物含有接着剤層であることが好ましい。 In recent years, in order to meet the demand for thinner polarizing plates, polarizing plates having a protective film on only one side of the polarizing element have been developed. Even in this configuration, it is preferable to laminate the protective film via the urea-based compound-containing adhesive layer of the present invention.
As a method for producing a polarizing plate having a protective film on only one side of the polarizing element, a method of first producing a polarizing plate in which a protective film is bonded to both sides via an adhesive layer and then peeling off one of the protective films is conceivable. However, when such a manufacturing method is used, only one of the adhesive layers may be the adhesive layer of the present invention, but the urea-based compound-containing adhesive layer of the present invention is the polarizing element. It is more preferable to use it on both sides.
When the urea-based compound-containing adhesive layer of the present invention is used only on one side of the polarizing element, it is preferable that the film-side adhesive layer that does not peel off is the urea-based compound-containing adhesive layer of the present invention.
　保護フィルムは、同時に他の光学的機能を有していてもよく、更に他の層が積層された積層構造に形成されていてもよい。
　この時の保護フィルムの膜厚は光学特性の観点から薄いものが好ましいが、薄すぎると強度が低下し加工性に劣るものとなる。適切な膜厚としては、５～１００μｍであり、好ましくは１０～８０μｍ、より好ましくは１５～７０μｍである。 The protective film may have other optical functions at the same time, and may be formed in a laminated structure in which other layers are laminated.
The film thickness of the protective film at this time is preferably thin from the viewpoint of optical characteristics, but if it is too thin, the strength is lowered and the workability is inferior. The appropriate film thickness is 5 to 100 μm, preferably 10 to 80 μm, and more preferably 15 to 70 μm.
　保護フィルムは、セルロースアシレート系樹脂フィルム、ポリカーボネート系樹脂からなるフィルム、ノルボルネンなどシクロオレフィン系樹脂からなるフィルム、（メタ）アクリル系重合体フィルム、ポリエチレンテレフタレートなどのポリエステル系樹脂フィルムなどのフィルムを用いることができる。
　偏光素子の両面に保護フィルムを有する構成の場合、ＰＶＡ系接着剤などの水系接着剤を用いて貼合する場合は透湿度の点で少なくとも片側の保護フィルムはセルロースアシレート系フィルムまたは（メタ）アクリル系重合体フィルムの何れかであることが好ましく、中でもセルロースアシレートフィルムが好ましい。 As the protective film, a film such as a cellulose acylate resin film, a polycarbonate resin film, a cycloolefin resin film such as norbornene, a (meth) acrylic polymer film, or a polyester resin film such as polyethylene terephthalate is used. be able to.
In the case of a configuration having protective films on both sides of the polarizing element, when bonding using a water-based adhesive such as a PVA-based adhesive, the protective film on at least one side is a cellulose acylate-based film or (meth) in terms of moisture permeability. Any of the acrylic polymer films is preferable, and the cellulose acylate film is particularly preferable.
　少なくとも一方の保護フィルムとしては、視野角補償などの目的で位相差機能を備えていても良く、その場合、フィルム自身が位相差機能を有していても良く、位相差層を別に有していても良く、両者の組み合わせであっても良い。
　なお、位相差機能を備えるフィルムは接着剤を介して、直接偏光素子に貼合される構成について説明したが、偏光素子に貼合された別の保護フィルムを介して粘着剤または接着剤を介して貼合された構成であっても構わない。 At least one protective film may have a retardation function for the purpose of compensating the viewing angle, and in that case, the film itself may have a retardation function and has a separate retardation layer. It may be a combination of both.
Although the configuration in which the film having the retardation function is directly bonded to the polarizing element via an adhesive has been described, the film is directly bonded to the polarizing element via an adhesive or an adhesive via another protective film bonded to the polarizing element. It does not matter if the structure is pasted together.
［画像表示装置の構成］
　本発明の偏光板、すなわち、偏光素子の少なくとも片面側に尿素系化合物含有接着剤層を介して透明保護フィルムが貼り合わされた偏光板は、液晶表示装置や有機ＥＬ表示装置等の各種画像表示装置に用いられる。特に、本発明の偏光板は、画像表示装置の視認側に前面板やタッチパネル等の透明部材が配置され、画像表示パネルと透明部材とが粘着剤層等により貼り合わせられた層間充填構成を有する画像表示装置に好適に用いられる。 [Configuration of image display device]
The polarizing plate of the present invention, that is, a polarizing plate in which a transparent protective film is bonded to at least one side of a polarizing element via a urea-based compound-containing adhesive layer, is a various image display device such as a liquid crystal display device or an organic EL display device. Used for. In particular, the polarizing plate of the present invention has an interlayer filling structure in which a transparent member such as a front plate or a touch panel is arranged on the visual side of the image display device, and the image display panel and the transparent member are bonded by an adhesive layer or the like. It is preferably used in an image display device.
（画像表示セル）
　画像表示セルとしては、液晶セルや有機ＥＬセルが挙げられる。液晶セルとしては、外光を利用する反射型液晶セル、バックライト等の光源からの光を利用する透過型液晶セル、外部からの光と光源からの光の両者を利用する半透過半反射型液晶セルのいずれを用いてもよい。液晶セルが光源からの光を利用するものである場合、画像表示装置（液晶表示装置）は、画像表示セル（液晶セル）の視認側と反対側にも偏光板が配置され、さらに光源が配置される。光源側の偏光板と液晶セルとは、適宜の粘着剤層を介して貼り合せられていることが好ましい。
液晶セルの駆動方式としては、例えばＶＡモード、ＩＰＳモード、ＴＮモード、ＳＴＮモードやベンド配向（π型）等の任意なタイプのものを用いうる。 (Image display cell)
Examples of the image display cell include a liquid crystal cell and an organic EL cell. The liquid crystal cell includes a reflective liquid crystal cell that uses external light, a transmissive liquid crystal cell that uses light from a light source such as a backlight, and a semi-transmissive semi-reflective type that uses both external light and light from a light source. Any of the liquid crystal cells may be used. When the liquid crystal cell uses the light from the light source, the image display device (liquid crystal display device) has a polarizing plate arranged on the side opposite to the viewing side of the image display cell (liquid crystal cell), and further arranges the light source. Will be done. It is preferable that the polarizing plate on the light source side and the liquid crystal cell are bonded to each other via an appropriate adhesive layer.
As the driving method of the liquid crystal cell, for example, any type such as VA mode, IPS mode, TN mode, STN mode and bend orientation (π type) can be used.
　有機ＥＬセルとしては、透明基板上に透明電極と有機発光層と金属電極とを順に積層して発光体（有機エレクトロルミネセンス発光体）を形成したもの等が好適に用いられる。有機発光層は、種々の有機薄膜の積層体であり、例えば、トリフェニルアミン誘導体等からなる正孔注入層と、アントラセン等の蛍光性の有機固体からなる発光層との積層体や、これらの発光層とペリレン誘導体等からなる電子注入層の積層体、あるいは正孔注入層、発光層、および電子注入層の積層体等、種々の層構成が採用され得る。 As the organic EL cell, a cell in which a transparent electrode, an organic light emitting layer, and a metal electrode are sequentially laminated on a transparent substrate to form a light emitting body (organic electroluminescence light emitting body) or the like is preferably used. The organic light emitting layer is a laminate of various organic thin films, for example, a laminate of a hole injection layer made of a triphenylamine derivative or the like and a light emitting layer made of a fluorescent organic solid such as anthracene, or a laminate of these. Various layer configurations can be adopted, such as a laminate of electron-injected layers composed of a light-emitting layer and a perylene derivative, or a laminate of hole-injected layers, light-emitting layers, and electron-injected layers.
（画像表示セルと偏光板の貼り合せ）
　画像表示セルと偏光板との貼り合せには、粘着剤層（粘着シート）が好適に用いられる。中でも、偏光板の一方の面に粘着剤層が付設された粘着剤層付き偏光板を画像表示セルと貼り合わせる方法が、作業性等の観点から好ましい。偏光板への粘着剤層の付設は、適宜な方式で行いうる。その例としては、例えば、トルエンや酢酸エチル等の適宜な溶剤の単独物または混合物からなる溶剤にベースポリマーまたはその組成物を溶解あるいは分散させた１０～４０重量％程度の粘着剤溶液を調製し、それを流延方式や塗工方式等の適宜な展開方式で偏光板上に直接付設する方式、あるいは前記に準じセパレータ上に粘着剤層を形成してそれを偏光板に移着する方式などが挙げられる。 (Attachment of image display cell and polarizing plate)
An adhesive layer (adhesive sheet) is preferably used for bonding the image display cell and the polarizing plate. Above all, a method in which a polarizing plate with an adhesive layer having an adhesive layer attached to one surface of the polarizing plate is attached to an image display cell is preferable from the viewpoint of workability and the like. The pressure-sensitive adhesive layer can be attached to the polarizing plate by an appropriate method. As an example, for example, a pressure-sensitive adhesive solution of about 10 to 40% by weight is prepared by dissolving or dispersing the base polymer or its composition in a solvent composed of a single substance or a mixture of appropriate solvents such as toluene and ethyl acetate. , A method of directly attaching it on a polarizing plate by an appropriate developing method such as a casting method or a coating method, or a method of forming an adhesive layer on a separator according to the above and transferring it to the polarizing plate, etc. Can be mentioned.
（粘着剤層）
　粘着剤層については、特開２０１８－０２５７６５号公報の段落［０１０３］～［０１４３］に記載されており、本発明ではこれらの粘着剤を用いることができる。 (Adhesive layer)
The pressure-sensitive adhesive layer is described in paragraphs [0103] to [0143] of JP-A-2018-025765, and these pressure-sensitive adhesives can be used in the present invention.
（前面透明部材）
　画像表示セルの視認側に配置される前面透明部材としては、前面板（ウインドウ層）やタッチパネル等が挙げられる。前面板としては、適宜の機械強度および厚みを有する透明板が用いられる。このような透明板としては、例えばアクリル系樹脂やポリカーボネート系樹脂のような透明樹脂板、あるいはガラス板等が用いられる。透明板の視認側には反射防止層などの機能層が積層されていても構わない。また、透明板が透明樹脂板の場合は、物理強度を上げるためにハードコート層や、透湿度を下げるために低透湿層が積層されていても構わない。
　タッチパネルとしては、抵抗膜方式、静電容量方式、光学方式、超音波方式等の各種タッチパネルや、タッチセンサー機能を備えるガラス板や透明樹脂板等が用いられる。前面透明部材として静電容量方式のタッチパネルが用いられる場合、タッチパネルよりもさらに視認側に、ガラスや透明樹脂板からなる前面板が設けられることが好ましい。 (Front transparent member)
Examples of the front transparent member arranged on the visual side of the image display cell include a front plate (window layer) and a touch panel. As the front plate, a transparent plate having appropriate mechanical strength and thickness is used. As such a transparent plate, for example, a transparent resin plate such as an acrylic resin or a polycarbonate resin, a glass plate, or the like is used. A functional layer such as an antireflection layer may be laminated on the visible side of the transparent plate. When the transparent plate is a transparent resin plate, a hard coat layer may be laminated to increase the physical strength, or a low moisture permeability layer may be laminated to reduce the moisture permeability.
As the touch panel, various touch panels such as a resistive film method, a capacitance method, an optical method, an ultrasonic method, and a glass plate or a transparent resin plate having a touch sensor function are used. When a capacitance type touch panel is used as the front transparent member, it is preferable to provide a front plate made of glass or a transparent resin plate on the visual side of the touch panel.
（偏光板と前面透明部材の貼り合せ）
　偏光板と前面透明部材との貼り合せには、粘着剤またはＵＶ硬化型の接着剤が好適に用いられる。粘着剤が用いられる場合、粘着剤の付設は適宜な方式で行い得る。具体的な付設方法としては、例えば、前述の画像表示セルと偏光板の貼り合せで用いた粘着剤層の付設方法が挙げられる。 (Lating the polarizing plate and the front transparent member)
A pressure-sensitive adhesive or a UV-curable adhesive is preferably used for bonding the polarizing plate and the front transparent member. When a pressure-sensitive adhesive is used, the pressure-sensitive adhesive can be attached by an appropriate method. As a specific attachment method, for example, the attachment method of the pressure-sensitive adhesive layer used for bonding the image display cell and the polarizing plate described above can be mentioned.
　ＵＶ硬化型の接着剤を用いる場合、硬化前の接着剤溶液の広がりを防止する目的で、画像表示パネル上の周縁部を囲むようにダム材が設けられ、ダム材上に前面透明部材を載置して、接着剤溶液を注入する方法が好適に用いられる。接着剤溶液の注入後は、必要に応じて位置合わせおよび脱泡が行われた後、ＵＶ光が照射されて硬化が行われる。 When a UV curable adhesive is used, a dam material is provided so as to surround the peripheral edge on the image display panel in order to prevent the adhesive solution from spreading before curing, and a front transparent member is placed on the dam material. A method of placing and injecting an adhesive solution is preferably used. After the injection of the adhesive solution, alignment and defoaming are performed as necessary, and then UV light is irradiated to perform curing.
　次に、偏光素子の少なくとも片面に尿素系化合物を少なくとも１種含有する接着剤層以外の尿素系化合物含有層を有する本発明の態様について説明する。
尚、前述のとおり、［尿素系化合物含有層］以外の［偏光素子］等の本発明を構成する技術要素については、尿素系化合物含有層が接着剤層である態様と共通である。 Next, an embodiment of the present invention having a urea-based compound-containing layer other than an adhesive layer containing at least one urea-based compound on at least one surface of the polarizing element will be described.
As described above, the technical elements constituting the present invention such as the [polarizing element] other than the [urea-based compound-containing layer] are common to the embodiment in which the urea-based compound-containing layer is an adhesive layer.
［尿素系化合物含有層］
　本発明のこの態様では、偏光板はヨウ素を吸着配向させてなるポリビニルアルコール系樹脂偏光素子の少なくとも一方の面に形成された尿素、尿素誘導体、チオ尿素及びチオ尿素誘導体から選ばれる少なくとも一種を含有する尿素系化合物含有層（接着剤層以外）を有する。
　尿素系化合物含有層は尿素系化合物を少なくとも１種とバインダーを有することが好ましい。バインダーとしてはポリマーバインダー、熱硬化型バインダー、活性エネルギー線硬化型バインダーなどが挙げられるが、本発明では何れのバインダーも好ましく用いることができる。 [Urea compound-containing layer]
In this aspect of the present invention, the polarizing plate contains at least one selected from urea, a urea derivative, thiourea and a thiourea derivative formed on at least one surface of a polyvinyl alcohol-based resin polarizing element formed by adsorbing and orienting iodine. It has a urea-based compound-containing layer (other than an adhesive layer).
The urea-based compound-containing layer preferably has at least one urea-based compound and a binder. Examples of the binder include a polymer binder, a thermosetting binder, and an active energy ray-curable binder, and any of the binders can be preferably used in the present invention.
　尿素系化合物含有層の厚みは、０．１～２０μｍであることが好ましく、０．５～１５μｍであることがより好ましく、１～１０μｍであることが更に好ましい。
　尿素系化合物含有層は偏光素子に直接積層されていても、他の層を介して積層されていても構わないが、偏光素子に直接積層されることが高温環境下での透過率低下を抑止し易い点で好ましい。
この態様における偏光板は、偏光素子の少なく一方の面に接着剤層を介して透明保護フィルムを有することが偏光板の物理強度を上げる点で好ましい。この時、接着剤層は尿素系化合物を含有していても、含有していなくても構わないが、含有していることがより好ましい。 The thickness of the urea-based compound-containing layer is preferably 0.1 to 20 μm, more preferably 0.5 to 15 μm, and even more preferably 1 to 10 μm.
The urea-based compound-containing layer may be laminated directly on the polarizing element or may be laminated via another layer, but the direct lamination on the polarizing element suppresses the decrease in transmittance in a high temperature environment. It is preferable because it is easy to do.
The polarizing plate in this embodiment preferably has a transparent protective film on at least one surface of the polarizing element via an adhesive layer in terms of increasing the physical strength of the polarizing plate. At this time, the adhesive layer may or may not contain the urea compound, but it is more preferable that the adhesive layer contains the urea compound.
　他の態様での保護フィルムの説明で記載したように、近年、偏光板の薄型化の要請に応えるために、偏光素子の片面にのみ保護フィルムを有する偏光板（以降、「片面保護フィルム付き偏光板」とも称す。）が開発されている。
このような構成に於いて物理強度を上げることなどを目的として、偏光素子の保護フィルムを有さない面に硬化層を積層する試みがなされている。（例えば特開２０１１－２２１１８５号公報） As described in the description of the protective film in other embodiments, in recent years, in order to meet the demand for thinner polarizing plates, a polarizing plate having a protective film on only one side of the polarizing element (hereinafter, "polarized light with a single-sided protective film"). Also called "plate") has been developed.
Attempts have been made to laminate a cured layer on a surface of a polarizing element that does not have a protective film, for the purpose of increasing the physical strength in such a configuration. (For example, Japanese Patent Application Laid-Open No. 2011-221185)
　本発明ではこのような硬化層に尿素系化合物を含有させることも好ましい態様の一つである。通常このような硬化層は有機溶剤を含む硬化性組成物から形成されるが、特開２０１７－０７５９８６号公報の段落［００２０］～［００４２］には活性エネルギー線硬化性高分子組成物の水性溶液から、このような硬化層を形成する方法が記載されている。尿素系化合物は水溶性のものが多いので、このような組成物に水溶性の尿素系化合物を含有させ、尿素系化合物含有層を形成するのも本発明の好ましい態様の一つである。 In the present invention, it is one of the preferable embodiments that the cured layer contains a urea compound. Normally, such a cured layer is formed from a curable composition containing an organic solvent, but paragraphs [0020] to [0042] of JP-A-2017-075986 describe the aqueous active energy ray-curable polymer composition. A method of forming such a hardened layer from a solution is described. Since many urea-based compounds are water-soluble, it is one of the preferred embodiments of the present invention to include a water-soluble urea-based compound in such a composition to form a urea-based compound-containing layer.
　次に、偏光素子の少なくとも片面に尿素系化合物含有溶液を塗布、乾燥して作製した偏光素子を有する、さらに他の態様の偏光板について説明する。
この態様は、層間充填構成用偏光板に用いられ、高温環境下で長時間さらされた場合でも単体透過率の低下を抑止する偏光素子に特徴を有するものである。この偏光素子は、ヨウ素が吸着配向された延伸ポリビニルアルコール系樹脂フィルムからなる偏光素子の少なくとも一方の面に、尿素、尿素誘導体、チオ尿素及びチオ尿素誘導体から選ばれる少なくとも１種を含有する溶液を塗布した後、この塗布液を乾燥することにより製造することができる。 Next, a polarizing plate of still another embodiment having a polarizing element prepared by applying a urea-based compound-containing solution to at least one surface of the polarizing element and drying it will be described.
This aspect is used for a polarizing plate for an interlayer filling structure, and is characterized by a polarizing element that suppresses a decrease in simple substance transmittance even when exposed to a high temperature environment for a long time. In this polarizing element, a solution containing at least one selected from urea, a urea derivative, a thiourea and a thiourea derivative is contained on at least one surface of the polarizing element made of a stretched polyvinyl alcohol-based resin film in which iodine is adsorbed and oriented. After coating, it can be produced by drying this coating liquid.
（尿素系化合物溶液）
　本発明の尿素系化合物含有溶液の溶媒は水、有機溶媒または、それらの混合液であることが好ましく、水または水とアルコールの混合溶媒の何れかであることがより好ましい。また、水とアルコールの混合溶媒である場合、アルコールがメタノールまたはエタノールの何れかであることが好ましい。
尿素系化合物は前記の尿素系化合物を好ましく使用することができるが、乾燥後に尿素系化合物が偏光素子の表面に析出し難い点で、尿素系化合物は水溶性であることが好ましい。 (Urea compound solution)
The solvent of the urea-based compound-containing solution of the present invention is preferably water, an organic solvent, or a mixed solution thereof, and more preferably water or a mixed solvent of water and alcohol. When the solvent is a mixed solvent of water and alcohol, the alcohol is preferably either methanol or ethanol.
As the urea-based compound, the above-mentioned urea-based compound can be preferably used, but the urea-based compound is preferably water-soluble in that the urea-based compound is unlikely to precipitate on the surface of the polarizing element after drying.
　以下、実施例に基づいて本発明を具体的に説明する。以下の実施例に示す材料、試薬、物質量とその割合、操作等は本発明の趣旨を逸脱しない限り適宜変更することができる。従って、本発明は以下の実施例に限定され制限されるものではない。 Hereinafter, the present invention will be specifically described based on Examples. The materials, reagents, amounts of substances and their ratios, operations, etc. shown in the following examples can be appropriately changed without departing from the spirit of the present invention. Therefore, the present invention is not limited to the following examples.
（偏光素子１の作製）
　平均重合度２４００、鹸化度９９．９モル％の膜厚４０μｍのＰＶＡフィルムを、２５℃の温水中に１２０秒間浸漬し膨潤させた。次いで、ヨウ素／ヨウ化カリウム（重量比＝２／３）の濃度０．６重量％の水溶液に浸漬し、２．１倍に延伸させながらＰＶＡフィルムを染色した。その後、６０℃のホウ酸とヨウ化カリウム含有の酸性浴中で延伸を行い、水洗、乾燥を施し、膜厚１５μｍの偏光素子１を作製した。 (Manufacturing of polarizing element 1)
A PVA film having an average degree of polymerization of 2400 and a saponification degree of 99.9 mol% and a film thickness of 40 μm was immersed in warm water at 25 ° C. for 120 seconds to swell. Next, the PVA film was dyed while being immersed in an aqueous solution having a concentration of iodine / potassium iodide (weight ratio = 2/3) of 0.6% by weight and stretched 2.1 times. Then, it was stretched in an acidic bath containing boric acid and potassium iodide at 60 ° C., washed with water and dried to prepare a polarizing element 1 having a film thickness of 15 μm.
（接着剤用ＰＶＡ溶液の調製）
　アセトアセチル基を含有する変性ＰＶＡ系樹脂（三菱ケミカル（株）製：ゴーセネックスＺ－４１０）５０ｇを９５０ｇの純水に溶解し、９０℃で２時間加熱後常温に冷却し、接着剤用ＰＶＡ溶液を得た。 (Preparation of PVA solution for adhesive)
50 g of a modified PVA resin containing an acetoacetyl group (manufactured by Mitsubishi Chemical Corporation: Gosenex Z-410) is dissolved in 950 g of pure water, heated at 90 ° C. for 2 hours and then cooled to room temperature to provide a PVA solution for adhesives. Got
（尿素系化合物溶液の調製）
　純水９０ｇに尿素１０ｇを添加し、尿素１０重量％水溶液を得た（溶液１）。同様に表１に従って、尿素を表１に記載の尿素系化合物に代え、必要に応じて溶媒を純水からメタノールに代え溶液２～９を調製した。 (Preparation of urea-based compound solution)
10 g of urea was added to 90 g of pure water to obtain a 10 wt% urea aqueous solution (solution 1). Similarly, according to Table 1, urea was replaced with the urea-based compound shown in Table 1, and the solvent was replaced with methanol from pure water as needed to prepare solutions 2 to 9.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
　上記で使用した、尿素、メチル尿素、エチル尿素、１，３－ジメチル尿素、テトラメチル尿素、フェニル尿素、チオ尿素、メチルチオ尿素、テトラヒドロ－２－ピリミジノンは何れも、東京化成工業株式会社の試薬を使用した。 The urea, methylurea, ethylurea, 1,3-dimethylurea, tetramethylurea, phenylurea, thiourea, methylthiourea, and tetrahydro-2-pyrimidinone used above are all reagents of Tokyo Kasei Kogyo Co., Ltd. used.
（偏光板用接着剤１の調製）
　上記で調製した、接着剤用ＰＶＡ溶液、尿素溶液、純水、メタノールを、ＰＶＡ濃度３．０％、メタノール濃度２０％、尿素濃度０．３％になるように配合し、偏光板用接着剤１を得た。 (Preparation of Adhesive 1 for Polarizing Plate)
The PVA solution for adhesive, urea solution, pure water, and methanol prepared above are blended so as to have a PVA concentration of 3.0%, a methanol concentration of 20%, and a urea concentration of 0.3%, and an adhesive for polarizing plates. I got 1.
（偏光板用接着剤２～１４の調製）
　同様に、接着剤用ＰＶＡ溶液、表１に記載の尿素系化合物の溶液、純水、メタノールを、ＰＶＡ濃度３．０％、メタノール濃度２０％、尿素系化合物濃度を表２に記載の濃度になるように配合し、偏光板用接着剤２～１４を得た。
　尚、偏光板用接着剤１２は、尿素系化合物としてメチル尿素と１，３－ジメチル尿素の２種類を併用するものであり、偏光板用接着剤１４は尿素系化合物を含有していない。 (Preparation of Adhesives 2 to 14 for Polarizing Plates)
Similarly, the PVA solution for adhesives, the urea-based compound solution shown in Table 1, pure water, and methanol are adjusted to the PVA concentration of 3.0%, the methanol concentration of 20%, and the urea-based compound concentration to the concentrations shown in Table 2. Adhesives 2 to 14 for polarizing plates were obtained.
The polarizing plate adhesive 12 uses two types of urea compounds, methylurea and 1,3-dimethylurea, in combination, and the polarizing plate adhesive 14 does not contain a urea compound.
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002
（セルロースアシレートフィルムの鹸化）
　市販のセルロースアシレートフィルムＴＤ４０（富士フイルム（株）製：膜厚４０μｍ）を、５５℃に保った１．５ｍｏｌ／ＬのＮａＯＨ水溶液（鹸化液）に２分間浸漬した後、フィルムを水洗し、その後、２５℃の０．０５ｍｏｌ／Ｌの硫酸水溶液に３０秒浸漬した後、更に水洗浴を３０秒流水下に通して、フィルムを中性の状態にした。そして、エアナイフによる水切りを３回繰り返し、水を落とした後に７０℃の乾燥ゾーンに１５秒間滞留させて乾燥し、鹸化処理したフィルムを作製した。 (Saponification of cellulose acylate film)
A commercially available cellulose acylate film TD40 (manufactured by FUJIFILM Corporation: film thickness 40 μm) was immersed in a 1.5 mol / L NaOH aqueous solution (saponification solution) maintained at 55 ° C. for 2 minutes, and then the film was washed with water. Then, after immersing the film in a 0.05 mol / L aqueous sulfuric acid solution at 25 ° C. for 30 seconds, the film was further passed through a water washing bath for 30 seconds under running water to make the film neutral. Then, draining with an air knife was repeated three times, and after the water was dropped, the film was allowed to stay in a drying zone at 70 ° C. for 15 seconds to dry, and a saponified film was prepared.
（偏光板１の作製）
　偏光素子１の両面に、上記で作成した鹸化処理したセルロースアシレートフィルムを、偏光板用接着剤１を介し、乾燥後の接着剤層の厚みが両面共、１００ｎｍになるように調整し、ロール貼合機を用いて貼合した後に６０℃で１０分間乾燥し、両面セルロースアシレートフィルム付き偏光板１を得た。 (Preparation of polarizing plate 1)
The saponified cellulose acylate film prepared above was placed on both sides of the polarizing element 1 via a polarizing plate adhesive 1 so that the thickness of the adhesive layer after drying was 100 nm on both sides, and rolled. After bonding using a bonding machine, the mixture was dried at 60 ° C. for 10 minutes to obtain a polarizing plate 1 with a double-sided cellulose acylate film.
（偏光板２～１４の作製）
　偏光板用接着剤１を偏光板用接着剤２～１４に代えた以外は偏光板１と同様に偏光板２～１４を作製した。 (Preparation of polarizing plates 2 to 14)
Polarizing plates 2 to 14 were produced in the same manner as the polarizing plate 1 except that the polarizing plate adhesive 1 was replaced with the polarizing plate adhesives 2 to 14.
（積層体１の作製）
　特開２０１８－０２５７６５号公報の実施例を参考に、上記で作製した偏光板１の両面にアクリル系粘着剤（製造元：リンテック（株）、品番：＃７）を塗布することにより、両面に、厚みが２５μｍの粘着剤層を有する光学積層体１を作製した。
（積層体２～１４の作製）
　光学積層体１と同様にして偏光板１を偏光板２～１４に代えた以外は同様にして光学積層体２～１４を作製した。 (Preparation of laminated body 1)
By applying an acrylic adhesive (manufacturer: Lintec Corporation, product number: # 7) to both sides of the polarizing plate 1 produced above, referring to the examples of JP-A-2018-0275765, both sides can be subjected to. An optical laminate 1 having an adhesive layer having a thickness of 25 μm was produced.
(Preparation of laminated bodies 2 to 14)
Optical laminates 2 to 14 were produced in the same manner as the optical laminate 1 except that the polarizing plate 1 was replaced with the polarizing plates 2 to 14.
（積層体１５の作製）
　光学積層体１４に対して粘着剤層を片面にのみ積層した以外は光学積層体１４と同様にして光学積層体１５を作製した。 (Preparation of laminated body 15)
The optical laminate 15 was produced in the same manner as the optical laminate 14 except that the pressure-sensitive adhesive layer was laminated on the optical laminate 14 on only one side.
（積層体の評価）
　特開２０１４－１０２３５３号公報と特開２０１８－０２５７６５号公報の実施例を参考に、上記で作製した積層体を評価した。尚、高温耐久試験は、９５℃と１０５℃で行い、９５℃では１０００時間まで高温耐久試験を行ったが、尿素系化合物の添加のない偏光板用接着剤１４を用いた比較例１以外は透過率低下が見られなかった。表３には１０５℃の高温耐久性試験の結果のみを示した。
比較例１の試験結果では１０５℃×１００時間の着色は９５℃×１０００時間の結果とほぼ一致した。 (Evaluation of laminated body)
The laminate prepared above was evaluated with reference to the examples of JP-A-2014-102353 and JP-A-2018-0275765. The high temperature durability test was carried out at 95 ° C. and 105 ° C., and the high temperature durability test was carried out at 95 ° C. for up to 1000 hours, except for Comparative Example 1 in which the polarizing plate adhesive 14 to which the urea compound was not added was used. No decrease in transmittance was observed. Table 3 shows only the results of the high temperature durability test at 105 ° C.
In the test result of Comparative Example 1, the coloring at 105 ° C. × 100 hours was almost the same as the result at 95 ° C. × 1000 hours.
［高温耐久試験後の単体透過率評価（１０５℃）］
　上記で作製した光学積層体１～１４を、それぞれ、５０ｍｍ×１００ｍｍの大きさに裁断して、第一粘着剤層および第二粘着剤層それぞれの表面を無アルカリガラス〔商品名“ＥＡＧＬＥ ＸＧ”、コーニング社製〕に貼合することによって、評価サンプルを作製した。また、光学積層体１５を、５０ｍｍ×１００ｍｍの大きさに裁断して、第一粘着剤層の表面を無アルカリガラス〔商品名“ＥＡＧＬＥ ＸＧ”、コーニング社製〕に貼合することによって、評価サンプルを作製した。尚、これらのサンプルを作製する時、ガラス板貼合前に水分量を調整するための加熱処理は行わなかった。
　この評価サンプルに、温度５０℃、圧力５ｋｇｆ／ｃｍ２（４９０．３ｋＰａ）で１時間オートクレーブ処理を施した後、温度２３℃、相対湿度５５％の環境下で２４時間放置した。その後、透過率を測定し（初期値）、温度１０５℃の加熱環境下に保管し、１００～２００時間まで５０時間おきに透過率を測定した。初期値に対し透過率低下が５％以上に達した時間を基に以下の基準で評価を行った。得られた結果を表３に示す。
尚、光学積層体１５を含む評価サンプルは、片側にのみ無アルカリガラスが積層されている構造であるため、透過率は低下せず、評価結果はＡであった。
２００時間後に透過率の低下が５％以下のもの　　　　　　　：Ａ
１５０～２００時間で透過率の低下が５％以上に達したもの：Ｂ
１００～１５０時間で透過率の低下が５％以上に達したもの：Ｃ
１００時間後に透過率の低下が５％以上のもの　　　　　　　：Ｄ [Evaluation of single transmittance after high temperature durability test (105 ° C)]
The optical laminates 1 to 14 produced above are each cut into a size of 50 mm × 100 mm, and the surfaces of the first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer are each made of non-alkali glass [trade name “EAGLE XG”. , Corning Inc.] to prepare an evaluation sample. Further, the optical laminate 15 is cut into a size of 50 mm × 100 mm, and the surface of the first pressure-sensitive adhesive layer is bonded to non-alkali glass [trade name “EAGLE XG”, manufactured by Corning Inc.) for evaluation. A sample was prepared. When these samples were prepared, no heat treatment was performed to adjust the water content before the glass plates were bonded.
This evaluation sample was autoclaved at a temperature of 50 ° C. and a pressure of 5 kgf / cm 2 (490.3 kPa) for 1 hour, and then left to stand in an environment of a temperature of 23 ° C. and a relative humidity of 55% for 24 hours. Then, the transmittance was measured (initial value), stored in a heating environment at a temperature of 105 ° C., and the transmittance was measured every 50 hours from 100 to 200 hours. The evaluation was performed according to the following criteria based on the time when the decrease in transmittance reached 5% or more with respect to the initial value. The results obtained are shown in Table 3.
Since the evaluation sample containing the optical laminate 15 has a structure in which non-alkali glass is laminated only on one side, the transmittance does not decrease and the evaluation result is A.
The decrease in transmittance is 5% or less after 200 hours: A
When the decrease in transmittance reached 5% or more in 150 to 200 hours: B
When the decrease in transmittance reached 5% or more in 100 to 150 hours: C
Those with a decrease in transmittance of 5% or more after 100 hours: D
［高温耐久試験後のクロス抜けの評価］
　光学積層体１５を、３０ｍｍ×３０ｍｍの大きさに裁断して、第一粘着剤層の表面を無アルカリガラス〔商品名“ＥＡＧＬＥ ＸＧ”、コーニング社製〕に貼合し、クロス評価用サンプル２０を作製した。
　高温耐久後の単体透過率評価サンプルを１００時間後の評価を行った後に、上記光学積層体とサンプル２０でクロスニコル状態の光抜け（以降、単に「クロス抜け」とも称す。）を目視で、以下の基準に従って評価した。
クロス抜けが全く見られないもの　　　　　　　：◎
クロス抜けが殆ど見られないもの　　　　　　　：○
クロス抜けが僅かに見られるもの　　　　　　　：△
クロス抜けがはっきり見られるもの　　　　　　：× [Evaluation of cross removal after high temperature durability test]
The optical laminate 15 is cut into a size of 30 mm × 30 mm, and the surface of the first pressure-sensitive adhesive layer is bonded to non-alkali glass [trade name “EAGLE XG”, manufactured by Corning Inc.), and the cloth evaluation sample 20 is used. Was produced.
After 100 hours of evaluation of the single transmittance evaluation sample after high temperature endurance, the optical laminate and the sample 20 visually show the light loss in the cross-nicol state (hereinafter, also simply referred to as "cross loss"). Evaluation was made according to the following criteria.
No cross omissions seen: ◎
Items with almost no cross omission: ○
Something with a slight cross omission: △
Those with clear cross omissions: ×
Figure JPOXMLDOC01-appb-T000003
Figure JPOXMLDOC01-appb-T000003
　表３の尿素系化合物の添加量について説明する。
接着剤に添加される尿素系化合物の添加量は、前述のとおり、ＰＶＡ１００重量部に対し、０．１～４００重量部であることが好ましく、１～２００重量部であることがより好ましく、３～１００重量部であることが更に好ましい。
　本実施例では、ＰＶＡ濃度は３．０％である。
　本発明では、何れの尿素系化合物も、その添加量が多い程、高温耐久試験後の単体透過率変化が小さく、逆に、高温耐久試験後のクロス抜けは、その添加量が少ないほど小さい傾向を示す。
　実施例に記載した尿素系化合物は、何れの化合物も、高温耐久試験後の単体透過率変化がＢ以上で、同時にクロス抜けが△以上の効果を示し、両方の性能において優れた効果を有している。 The amount of the urea compound added in Table 3 will be described.
As described above, the amount of the urea compound added to the adhesive is preferably 0.1 to 400 parts by weight, more preferably 1 to 200 parts by weight, based on 100 parts by weight of PVA. It is more preferably up to 100 parts by weight.
In this example, the PVA concentration is 3.0%.
In the present invention, the larger the amount of any urea compound added, the smaller the change in simple substance transmittance after the high temperature durability test, and conversely, the smaller the amount of the added amount, the smaller the cross loss after the high temperature durability test. Is shown.
All of the urea compounds described in the examples have an effect of a simple substance transmittance change of B or more after the high temperature durability test and a cross loss of Δ or more at the same time, and have excellent effects in both performances. ing.
　但し、上記化合物の配合量については、個々の化合物によって、好ましい性能、すなわち、単体透過率変化がＢ以上で、同時にクロス抜けが△以上の性能を示す添加量範囲が厳密には異なるが、いずれの化合物もその添加量は、前記好ましい添加量の範囲に適正範囲を有している。
　表３に記載の添加量は、各尿素系化合物において、単体透過率が評価Ａとなる最小添加量の値を示している。さらに、尿素、チオ尿素については、評価Ａとなる最小添加量から添加量を徐々に減らし、クロス抜けが△から○となる添加量の値も示す（その時の単体透過率変化はＢだった。）。また、メチル尿素については、評価Ａとなる最小添加量から添加量を徐々に減らし、クロス抜けが○から◎となる添加量の結果も示す（その時の単体透過率変化はＢだった。）。 However, regarding the blending amount of the above compounds, the range of the amount of addition which shows preferable performance, that is, performance of elemental transmittance change of B or more and cross loss of Δ or more at the same time differs depending on each compound. The addition amount of the above compound also has an appropriate range within the above-mentioned preferable addition amount range.
The addition amount shown in Table 3 shows the value of the minimum addition amount at which the simple substance transmittance is evaluated A in each urea-based compound. Further, for urea and thiourea, the addition amount was gradually reduced from the minimum addition amount to be evaluated A, and the value of the addition amount from Δ to ◯ was also shown (the change in the single transmittance at that time was B). ). In addition, for methylurea, the addition amount was gradually reduced from the minimum addition amount that was evaluated as A, and the result of the addition amount that the cross loss changed from ◯ to ◎ is also shown (the change in single transmittance at that time was B).
　表３に示す結果から以下のことが明らかである。
１．尿素系化合物を含有する接着剤を用いた、本発明の偏光板は層間充填構成の画像表示装置に用いられた場合においても、高温環境下で長時間さらされた場合でも単体透過率の低下を抑止できる。
２．特に、尿素またはチオ尿素を用いたものに対し尿素誘導体またはチオ尿素誘導体を用いたものは単体透過率の低下がないことに加え、クロス抜けもなく、特に良好である。
３．尿素系化合物を２種類含有する接着剤を用いたものも、高温環境下で長時間さらされた場合でも単体透過率の低下を抑止でき、本発明の好ましい態様の一つである。 From the results shown in Table 3, the following is clear.
1. 1. The polarizing plate of the present invention using an adhesive containing a urea compound reduces the transmittance of a single substance even when it is used in an image display device having an interlayer filling structure and when it is exposed to a high temperature environment for a long time. It can be deterred.
2. In particular, the one using a urea derivative or a thiourea derivative as opposed to the one using urea or thiourea is particularly good because there is no decrease in the single transmittance and no cross loss.
3. 3. An adhesive containing two types of urea-based compounds is also one of the preferred embodiments of the present invention because it can suppress a decrease in elemental transmittance even when exposed to a high temperature environment for a long time.
　次に、他の態様の例を示すが、この態様においても以下の例に限定され制限されるものではない。
　特開２０１７－０７５９８６号公報の段落［００７５］～［００７６］に記載の硬化層形成用組成物ＢＬＣ－１の組成に対し、メチル尿素の固形分濃度が１重量％になるようにメチル尿素を加え、全体の固形分濃度が２６重量％になるように純水を加え、混合後、超音波を照射した後、ポアサイズ５μｍのフィルターを通して、尿素系化合物含有硬化性組成物（ＵＢＬＣ－１）を調製した。 Next, examples of other embodiments will be shown, but the present embodiment is not limited to the following examples.
Methylurea is added so that the solid content concentration of methylurea is 1% by weight based on the composition of the cured layer forming composition BLC-1 described in paragraphs [0075] to [0076] of JP-A-2017-075986. In addition, pure water is added so that the total solid content concentration becomes 26% by weight, and after mixing, the urea-based compound-containing curable composition (UBLC-1) is passed through a filter having a pore size of 5 μm after being irradiated with ultrasonic waves. Prepared.
　特開２０１７－０７５９８６号公報の段落［００７０］～［００８０］に記載の偏光板１を参考に、尿素化合物を含有しない硬化層付き片面保護フィルム付き偏光板（偏光板２２）を作製した。
　偏光板２２に対し、硬化形成用組成物（ＢＬＣ－１）から硬化形成用組成物（ＵＢＬＣ－１）に代えた以外は同様にして、尿素化合物含有硬化層付き片面保護フィルム付き偏光板（偏光板２１）を作製した。
　光学積層体１４に対し、偏光板１４を夫々、偏光板２１、偏光板２２に代えた以外は同様にして、光学積層体２１と光学積層体２２を得た。これらの試料を光学積層１４と同様に評価し、得られた結果を表４に示す。
　尚、高温耐久後のクロス抜けの評価は、透明保護フィルム面が外側になるようにして行った。 A polarizing plate with a single-sided protective film (polarizing plate 22) with a cured layer containing no urea compound was prepared with reference to the polarizing plate 1 described in paragraphs [0070] to [0080] of JP-A-2017-075986.
The polarizing plate 22 is similarly subjected to a polarizing plate with a single-sided protective film having a curing layer containing a urea compound (polarized light) except that the curing forming composition (BLC-1) is replaced with the curing forming composition (UBLC-1). A plate 21) was produced.
An optical laminate 21 and an optical laminate 22 were obtained in the same manner as for the optical laminate 14 except that the polarizing plate 14 was replaced with the polarizing plate 21 and the polarizing plate 22, respectively. These samples were evaluated in the same manner as in the optical lamination 14, and the results obtained are shown in Table 4.
The evaluation of the cloth coming off after high temperature durability was performed so that the transparent protective film surface was on the outside.
Figure JPOXMLDOC01-appb-T000004
Figure JPOXMLDOC01-appb-T000004
　表４に示す結果から以下のことが明らかである。
１．偏光素子の少なくとも一方の面に尿素系化合物含有層を設けた本発明の偏光板は層間充填構成の画像表示装置に用いられた場合においても、高温環境下で長時間さらされた場合でも単体透過率の低下を抑止できる。 From the results shown in Table 4, the following is clear.
1. 1. The polarizing plate of the present invention provided with a urea-based compound-containing layer on at least one surface of a polarizing element transmits a single substance even when used in an image display device having an interlayer filling configuration or when exposed to a high temperature environment for a long time. The decrease in rate can be suppressed.
　さらに他の態様の例を示すが、この態様においても以下の例に限定され制限されるものではない。
　塗布液としてメチル尿素の０．５％溶液を調製した。上記で作製した偏光素子１の片面にバーコータを用いてメチル尿素の０．５％溶液を、ウェット塗布量が１０μｍになるように塗布し６０℃で５分乾燥し偏光素子２を得た。
　比較例として、上記で作製した偏光素子の片面にバーコータを用いて純水を、ウェット塗布量が１０μｍになるように塗布し６０℃で５分乾燥し偏光素子３を得た。 Although examples of still other embodiments are shown, the present embodiment is not limited to the following examples.
A 0.5% solution of methylurea was prepared as a coating solution. A 0.5% solution of methylurea was applied to one side of the polarizing element 1 produced above using a bar coater so that the wet application amount was 10 μm, and dried at 60 ° C. for 5 minutes to obtain a polarizing element 2.
As a comparative example, pure water was applied to one side of the polarizing element produced above using a bar coater so that the wet coating amount was 10 μm, and dried at 60 ° C. for 5 minutes to obtain a polarizing element 3.
　偏光板１４に対し、偏光素子１を夫々、偏光素子２、偏光素子３に代えた以外は同様にして偏光板３１と偏光板３２を得た。
　光学積層体１４に対し、偏光板１４を夫々、偏光板３１、偏光板３２に代えた以外は同様にして、光学積層体３１と光学積層体３２を得た。これらの試料を光学積層１４と同様に評価し、得られた結果を表５に示す。 A polarizing plate 31 and a polarizing plate 32 were obtained in the same manner with respect to the polarizing plate 14, except that the polarizing element 1 was replaced with the polarizing element 2 and the polarizing element 3, respectively.
An optical laminate 31 and an optical laminate 32 were obtained in the same manner with respect to the optical laminate 14 except that the polarizing plate 14 was replaced with the polarizing plate 31 and the polarizing plate 32, respectively. These samples were evaluated in the same manner as in the optical lamination 14, and the results obtained are shown in Table 5.
Figure JPOXMLDOC01-appb-T000005
Figure JPOXMLDOC01-appb-T000005
　表５に示す結果から以下のことが明らかである。
１．偏光素子の少なくとも一方の面に尿素系化合物を含有する溶液を塗布、乾燥して作製した偏光素子を有する、本発明の偏光板は層間充填構成の画像表示装置に用いられた場合においても、高温環境下で長時間さらされた場合でも単体透過率の低下を抑止できる。 From the results shown in Table 5, the following is clear.
1. 1. The polarizing plate of the present invention, which has a polarizing element prepared by applying a solution containing a urea compound to at least one surface of the polarizing element and drying it, has a high temperature even when used in an image display device having an interlayer filling configuration. Even when exposed to the environment for a long time, the decrease in single transmittance can be suppressed.

Claims (12)

  1. ヨウ素を吸着配向させてなるポリビニルアルコール系樹脂偏光素子、
    前記偏光素子の少なくとも一方の面に形成された、尿素、尿素誘導体、チオ尿素及びチオ尿素誘導体から選ばれる少なくとも一種を含有する尿素系化合物含有層、及び
    透明保護フィルム
    を有することを特徴とする偏光板。     Polyvinyl alcohol-based resin polarizing element, which is made by adsorbing and orienting iodine,
    Polarizing characterized by having a urea-based compound-containing layer containing at least one selected from urea, a urea derivative, thiourea and a thiourea derivative, and a transparent protective film formed on at least one surface of the polarizing element. Board.
  2. 前記尿素系化合物含有層が接着剤層であり、前記透明保護フィルムが該接着剤層を介して貼合されていることを特徴とする請求項１に記載の偏光板。 The polarizing plate according to claim 1, wherein the urea-based compound-containing layer is an adhesive layer, and the transparent protective film is bonded via the adhesive layer.
  3. 前記接着剤層が、更にポリビニルアルコール系樹脂を含有することを特徴とする請求項２に記載の偏光板。 The polarizing plate according to claim 2, wherein the adhesive layer further contains a polyvinyl alcohol-based resin.
  4. 前記接着剤層に含有される尿素系化合物の合計含有量が、ポリビニルアルコール系樹脂１００重量部に対し、１重量部以上４００重量部以下であることを特徴とする請求項３に記載の偏光板。 The polarizing plate according to claim 3, wherein the total content of the urea-based compound contained in the adhesive layer is 1 part by weight or more and 400 parts by weight or less with respect to 100 parts by weight of the polyvinyl alcohol-based resin. ..
  5. 前記尿素系化合物が、尿素誘導体及び／又はチオ尿素誘導体であることを特徴とする請求項１～４のいずれかに記載の偏光板。 The polarizing plate according to any one of claims 1 to 4, wherein the urea compound is a urea derivative and / or a thiourea derivative.
  6. 前記接着剤層の厚みが、０．０１～７μｍであることを特徴とする請求項２～５のいずれかに記載の偏光板。 The polarizing plate according to any one of claims 2 to 5, wherein the thickness of the adhesive layer is 0.01 to 7 μm.
  7. 前記尿素系化合物含有層が接着剤層以外の樹脂層であることを特徴とする請求項１に記載の偏光板。 The polarizing plate according to claim 1, wherein the urea-based compound-containing layer is a resin layer other than the adhesive layer.
  8. 前記偏光板が、層間充填構成を有する画像表示装置に用いられるものであることを特徴とする請求項１～７のいずれかに記載の偏光板。 The polarizing plate according to any one of claims 1 to 7, wherein the polarizing plate is used in an image display device having an interlayer filling structure.
  9. 偏光素子の少なくとも一方の面に透明保護フィルムが貼合された偏光板を製造する方法であって、
    ヨウ素が吸着配向された延伸ポリビニルアルコール系樹脂フィルムからなる偏光素子の少なくとも一方の面に、
    ポリビニルアルコール系樹脂、及び
    尿素、尿素誘導体、チオ尿素及びチオ尿素誘導体から選ばれる少なくとも１種を含有する接着剤組成物を用いて接着剤層を形成する工程、
    上記接着剤層を形成する工程と同時又は形成後、該接着剤層を介し透明保護フィルムを貼合する工程を含むことを特徴とする偏光板の製造方法。     A method for manufacturing a polarizing plate in which a transparent protective film is bonded to at least one surface of a polarizing element.
    On at least one surface of a polarizing element made of a stretched polyvinyl alcohol-based resin film in which iodine is adsorbed and oriented,
    A step of forming an adhesive layer using an adhesive composition containing a polyvinyl alcohol-based resin and at least one selected from urea, a urea derivative, thiourea and a thiourea derivative.
    A method for producing a polarizing plate, which comprises a step of laminating a transparent protective film through the adhesive layer at the same time as or after the step of forming the adhesive layer.
  10. 請求項１～８のいずれかに記載の偏光板が画像表示セルの視認側表面に粘着剤層を介して貼り合わされている画像表示パネル、及び
    前記画像表示パネルの視認側偏光板面に粘着剤層を介して貼り合わされた透明部材、
    を有することを特徴とする画像表示装置。     An adhesive agent is applied to an image display panel in which the polarizing plate according to any one of claims 1 to 8 is bonded to the visible side surface of the image display cell via an adhesive layer, and to the visible side polarizing plate surface of the image display panel. Transparent members bonded together via layers,
    An image display device characterized by having.
  11. 前記透明部材が、ガラス板または透明樹脂板であることを特徴とする請求項１０に記載の画像表示装置。 The image display device according to claim 10, wherein the transparent member is a glass plate or a transparent resin plate.
  12. 前記透明部材が、タッチパネルであることを特徴とする請求項１０に記載の画像表示装置。 The image display device according to claim 10, wherein the transparent member is a touch panel.
PCT/JP2020/018656 2019-05-15 2020-05-08 Polarizing plate, method for manufacturing polarizing plate, and image display device using said polarizing plate WO2020230717A1 (en)

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