CN112703436B - Polarizing film, polarizing plate comprising same and display device - Google Patents

Polarizing film, polarizing plate comprising same and display device Download PDF

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Publication number
CN112703436B
CN112703436B CN201980060636.6A CN201980060636A CN112703436B CN 112703436 B CN112703436 B CN 112703436B CN 201980060636 A CN201980060636 A CN 201980060636A CN 112703436 B CN112703436 B CN 112703436B
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compound
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liquid crystal
protective layer
polymerizable
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CN112703436A (en
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太田阳介
永安智
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Sumitomo Chemical Co Ltd
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Sumitomo Chemical Co Ltd
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    • GPHYSICS
    • G02OPTICS
    • G02BOPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B1/00Optical elements characterised by the material of which they are made; Optical coatings for optical elements
    • G02B1/10Optical coatings produced by application to, or surface treatment of, optical elements
    • G02B1/14Protective coatings, e.g. hard coatings
    • HELECTRICITY
    • H10SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10KORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K59/00Integrated devices, or assemblies of multiple devices, comprising at least one organic light-emitting element covered by group H10K50/00
    • H10K59/80Constructional details
    • H10K59/8791Arrangements for improving contrast, e.g. preventing reflection of ambient light
    • CCHEMISTRY; METALLURGY
    • C08ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08JWORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J5/00Manufacture of articles or shaped materials containing macromolecular substances
    • C08J5/18Manufacture of films or sheets
    • CCHEMISTRY; METALLURGY
    • C08ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08JWORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J7/00Chemical treatment or coating of shaped articles made of macromolecular substances
    • C08J7/04Coating
    • C08J7/042Coating with two or more layers, where at least one layer of a composition contains a polymer binder
    • CCHEMISTRY; METALLURGY
    • C08ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08KUse of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K5/00Use of organic ingredients
    • C08K5/0008Organic ingredients according to more than one of the "one dot" groups of C08K5/01 - C08K5/59
    • C08K5/0041Optical brightening agents, organic pigments
    • CCHEMISTRY; METALLURGY
    • C08ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08KUse of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K5/00Use of organic ingredients
    • C08K5/16Nitrogen-containing compounds
    • C08K5/22Compounds containing nitrogen bound to another nitrogen atom
    • C08K5/23Azo-compounds
    • CCHEMISTRY; METALLURGY
    • C09DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09DCOATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
    • C09D4/00Coating compositions, e.g. paints, varnishes or lacquers, based on organic non-macromolecular compounds having at least one polymerisable carbon-to-carbon unsaturated bond ; Coating compositions, based on monomers of macromolecular compounds of groups C09D183/00 - C09D183/16
    • CCHEMISTRY; METALLURGY
    • C09DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09KMATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
    • C09K19/00Liquid crystal materials
    • C09K19/02Liquid crystal materials characterised by optical, electrical or physical properties of the components, in general
    • GPHYSICS
    • G02OPTICS
    • G02BOPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B1/00Optical elements characterised by the material of which they are made; Optical coatings for optical elements
    • G02B1/08Optical elements characterised by the material of which they are made; Optical coatings for optical elements made of polarising materials
    • GPHYSICS
    • G02OPTICS
    • G02BOPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00Optical elements other than lenses
    • G02B5/30Polarising elements
    • GPHYSICS
    • G02OPTICS
    • G02BOPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00Optical elements other than lenses
    • G02B5/30Polarising elements
    • G02B5/3016Polarising elements involving passive liquid crystal elements
    • GPHYSICS
    • G02OPTICS
    • G02BOPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00Optical elements other than lenses
    • G02B5/30Polarising elements
    • G02B5/3025Polarisers, i.e. arrangements capable of producing a definite output polarisation state from an unpolarised input state
    • G02B5/3033Polarisers, 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
    • GPHYSICS
    • G02OPTICS
    • G02BOPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00Optical elements other than lenses
    • G02B5/30Polarising elements
    • G02B5/3083Birefringent or phase retarding elements
    • GPHYSICS
    • G02OPTICS
    • G02FOPTICAL 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
    • G02F1/00Devices 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
    • G02F1/01Devices 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 
    • G02F1/13Devices 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
    • GPHYSICS
    • G02OPTICS
    • G02FOPTICAL 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
    • G02F1/00Devices 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
    • G02F1/01Devices 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 
    • G02F1/13Devices 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
    • G02F1/133Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333Constructional arrangements; Manufacturing methods
    • G02F1/1335Structural association of cells with optical devices, e.g. polarisers or reflectors
    • GPHYSICS
    • G02OPTICS
    • G02FOPTICAL 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
    • G02F1/00Devices 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
    • G02F1/01Devices 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 
    • G02F1/13Devices 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
    • G02F1/133Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333Constructional arrangements; Manufacturing methods
    • G02F1/1335Structural association of cells with optical devices, e.g. polarisers or reflectors
    • G02F1/133528Polarisers
    • GPHYSICS
    • G02OPTICS
    • G02FOPTICAL 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
    • G02F1/00Devices 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
    • G02F1/01Devices 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 
    • G02F1/13Devices 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
    • G02F1/133Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333Constructional arrangements; Manufacturing methods
    • G02F1/1335Structural association of cells with optical devices, e.g. polarisers or reflectors
    • G02F1/13363Birefringent elements, e.g. for optical compensation
    • GPHYSICS
    • G09EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09FDISPLAYING; ADVERTISING; SIGNS; LABELS OR NAME-PLATES; SEALS
    • G09F9/00Indicating arrangements for variable information in which the information is built-up on a support by selection or combination of individual elements
    • G09F9/30Indicating arrangements for variable information in which the information is built-up on a support by selection or combination of individual elements in which the desired character or characters are formed by combining individual elements
    • HELECTRICITY
    • H05ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05BELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B33/00Electroluminescent light sources
    • H05B33/02Details
    • HELECTRICITY
    • H10SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10KORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K59/00Integrated devices, or assemblies of multiple devices, comprising at least one organic light-emitting element covered by group H10K50/00
    • H10K59/50OLEDs integrated with light modulating elements, e.g. with electrochromic elements, photochromic elements or liquid crystal elements

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  • Physics & Mathematics (AREA)
  • Chemical & Material Sciences (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Nonlinear Science (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Organic Chemistry (AREA)
  • Engineering & Computer Science (AREA)
  • Polymers & Plastics (AREA)
  • Health & Medical Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Medicinal Chemistry (AREA)
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  • Materials Engineering (AREA)
  • Manufacturing & Machinery (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Wood Science & Technology (AREA)
  • Theoretical Computer Science (AREA)
  • Polarising Elements (AREA)
  • Liquid Crystal (AREA)
  • Devices For Indicating Variable Information By Combining Individual Elements (AREA)

Abstract

A polarizing film comprising, in order, a polarizer, a 1 st protective layer, and a 2 nd protective layer, wherein the polarizer is a cured product of a polymerizable liquid crystal composition comprising a polymerizable liquid crystal compound having at least one polymerizable group and a dichroic dye, the 1 st protective layer is a cured product layer of a curable composition comprising a water-soluble resin, and the 2 nd protective layer is a cured product layer of a curable composition comprising a polymerizable compound.

Description

Polarizing film, polarizing plate comprising same and display device
Technical Field
The present invention relates to a polarizing film, a polarizing plate including the polarizing film, and a display device including the polarizing film.
Background
In the past, polarizing plates have been used by being attached to image display elements such as liquid crystal cells and organic electroluminescent (organic EL) display elements in various image display panels such as liquid crystal display panels and organic EL display panels. As such a polarizing plate, a polarizing plate having the following structure is known: a protective layer such as a triacetyl cellulose film is laminated on at least one surface of a polarizer obtained by adsorbing and orienting a compound exhibiting dichroism such as iodine or a dichroism dye on a polyvinyl alcohol resin film via an adhesive layer.
In recent years, there has been a demand for further thinning of displays such as image display panels, and further thinning of polarizing plates and polarizers, which are one of the constituent elements thereof, has been demanded. For example, thin type host-guest polarizers formed of a polymerizable liquid crystal compound and a compound exhibiting dichroism have been proposed for such requirements (patent documents 1 to 3).
Prior art literature
Patent literature
Patent document 1: japanese patent publication No. 2007-510946
Patent document 2: japanese patent laid-open publication No. 2013-37353
Patent document 3: japanese patent laid-open No. 2017-083843
Disclosure of Invention
Problems to be solved by the invention
However, when the main guest polarizer described in patent document 1 is bonded to a polymer film such as a protective layer or an image display device, there is a problem that the dichroic dye contained in the polarizer is likely to diffuse into the polymer film or the adhesive layer depending on the external environmental conditions to which the polarizer is exposed, and the polarizing performance is degraded with time due to disturbance of anisotropy.
Such a decline in polarization performance over time becomes particularly remarkable in severe environments such as high temperature and high humidity.
In order to solve the above problems, in the polarizing film described in patent document 2, a polarizing film in which an alignment layer, a polarizing layer, and a protective layer are formed on a transparent substrate is disposed in-line with a front panel (glass substrate). However, in the case of forming the protective layer constituting the polarizing film described in patent document 2, a solvent drying step is necessary, and in the drying step, a dichroic compound in the polarizer is likely to diffuse into the protective layer depending on the kind of solvent contained in the composition for forming the protective layer and the kind of the protective layer to be constructed, and thus, a decline in polarizing performance occurs with time.
Further, patent document 3 teaches that: by sealing both sides of the polarizing film with the diffusion preventing layer, the dichromatic pigment can be prevented from diffusing out of the polarizing film, and the deterioration of the optical performance of the polarizing plate with time can be suppressed. However, in patent document 3, the hydrophilic compound such as polyvinyl alcohol proposed as the diffusion preventing layer is insufficient in acid resistance, and when such a polarizing plate is assembled to a display device or the like adjacent to, for example, an adhesive layer, the diffusion preventing layer itself is degraded by the acid contained in the adhesive layer, whereby the transmittance is easily lowered, or the dichroic dye such as azo dye contained in the polarizer is easily degraded, and further, the function of the diffusion preventing layer is lowered, whereby the dichroic dye diffuses from the polarizer to the outside of the polarizer, and thus, the polarizing performance may be lowered with time. In addition, there are the following problems: in a high humidity environment, cracks, peeling, floating and the like are liable to occur, and haze increases.
Accordingly, an object of the present application is to solve the above-described problems that may occur in the prior art, and to provide a polarizing film that has high acid resistance and can effectively suppress the decrease in polarization performance (particularly, the decrease in polarization performance in severe environments such as high temperature and high humidity) due to the diffusion of a dichroic dye, and that is preferably thin. The present application also provides a polarizing plate and a display device including the polarizing film.
Means for solving the problems
The present inventors have conducted intensive studies to solve the above-mentioned problems, and as a result, have completed the present application. That is, the present application provides the following preferred embodiments.
[1] A polarizing film comprising, in order, a polarizer, a 1 st protective layer, and a 2 nd protective layer, the polarizer being a cured product of a polymerizable liquid crystal composition comprising a polymerizable liquid crystal compound having at least one polymerizable group and a dichroic dye,
the 1 st protective layer is a cured product layer of a curable composition containing a water-soluble resin,
the 2 nd protective layer is a cured product layer of a curable composition containing a polymerizable compound.
[2] The polarizing film according to [1], wherein the curable composition in the 2 nd protective layer contains a cationically polymerizable compound as the polymerizable compound.
[3] The polarizing film according to the item [1] or [2], wherein the curable composition in the 2 nd protective layer contains a polymerizable compound having a cyclic ether structure as the polymerizable compound.
[4] The polarizing film according to any one of [1] to [3], wherein the curable composition in the 2 nd protective layer comprises an oxetane compound having an oxetanyl group as a polymerizable compound.
[5] The polarizing film according to any one of [1] to [4], wherein the curable composition in the 2 nd protective layer comprises an oxetane compound having two or more oxetanes as a polymerizable compound.
[6] The polarizing film according to item [5], wherein the content of the oxetane compound having two or more oxetanes is 30 parts by mass or more based on 100 parts by mass of the total amount of all polymerizable compounds contained in the curable composition for forming the 2 nd protective layer.
[7] The polarizing film according to any one of [1] to [6], wherein the dichroic dye is an azo dye.
[8] The polarizing film according to any one of [1] to [7], wherein the polymerizable liquid crystal compound exhibits a smectic liquid crystal phase.
[9] The polarizing film according to any one of [1] to [8], wherein the polarizer exhibits a Bragg peak in an X-ray analysis measurement.
[10] A polarizing plate comprising the polarizing film according to any one of [1] to [9] and a retardation film, wherein the retardation film satisfies the formula (X):
100≤Re(550)≤180 (X)
[ in the case of Re (550) represents the in-plane phase difference at a wavelength of 550nm ]
The angle between the slow axis of the retardation film and the absorption axis of the polarizing film is substantially 45 °.
[11] The polarizing plate according to [10], wherein the retardation film satisfies the formula (Y):
Re(450)/Re(550)<1 (Y)
in the formula, re (450) and Re (550) represent the in-plane phase difference values at wavelengths of 450nm and 550nm, respectively.
[12] A display device comprising the polarizing film of any one of [1] to [9] or the polarizing plate of any one of [10] to [11 ].
ADVANTAGEOUS EFFECTS OF INVENTION
According to the present invention, a thin polarizing film having high acid resistance and capable of effectively suppressing the deterioration of polarizing performance with time (particularly, the deterioration with time in a severe environment such as high temperature, high humidity, etc.) caused by the diffusion of a dichroic dye can be provided.
Detailed Description
Hereinafter, embodiments of the present invention will be described in detail. The scope of the present invention is not limited to the embodiments described herein, and various modifications may be made without departing from the spirit of the present invention.
< polarizing film >
The polarizing film of the present invention comprises a polarizer, a 1 st protective layer and a 2 nd protective layer, which are laminated in this order. In the polarizing film of the present invention, the polarizer is a cured product of a polymerizable liquid crystal composition containing a polymerizable liquid crystal compound having at least one polymerizable group and a dichroic dye, the 1 st protective layer is a cured product layer of a curable composition containing a water-soluble resin (hereinafter, also referred to as "curable composition (1)"), and the 2 nd protective layer is a cured product layer of a curable composition containing a polymerizable compound (hereinafter, referred to as "curable composition (2)").
In a polarizer manufactured by curing a polymerizable liquid crystal composition containing a polymerizable liquid crystal compound and a dichroic dye, the dichroic dye is polymerized and cured in a state in which the dichroic dye is encapsulated by the polymerizable liquid crystal compound and the dichroic dye are aligned, but compared with a polarizer obtained by adsorbing and aligning the dichroic dye to a polyvinyl alcohol resin film widely used in the past, the dichroic dye is less likely to be held in a polymer component, and there is a tendency that: the dichroic dye thermally diffuses from the polarizer to other layers laminated with the polarizer, and tends to cause a decline in polarizing performance over time.
In contrast, the polarizing film of the present invention has improved heat resistance by providing the 1 st protective layer, which is a cured product of the curable composition (1) containing a water-soluble resin, on one surface of the polarizer, and can ensure a high effect of suppressing diffusion of the dichroic dye out of the polarizer even in a high-temperature environment. Further, by providing the 2 nd protective layer as a cured product of the curable composition (2) containing a polymerizable compound on the 1 st protective layer, it is possible to secure wet heat resistance and to suppress degradation of the dichroic dye due to an acid contained in the adhesive layer or the like when the polarizing film of the present invention is assembled to a polarizing plate, a display device or the like via the adhesive layer. Thus, the polarizing film of the present invention can effectively suppress the decrease in polarization performance over time even in a high-temperature or high-temperature and high-humidity environment. Further, since the effects of the respective protective layers can be synergistically exhibited by stacking the 1 st protective layer and the 2 nd protective layer in the above order, the thickness of the protective layers can be made thinner, and a thinner polarizing film can be obtained.
In the present invention, as the water-soluble resin contained in the curable composition (1) for forming the 1 st protective layer, water-soluble resins known in the art can be used, and examples thereof include polyvinyl alcohol resins, water-soluble epoxy resins, water-soluble acrylic resins, water-soluble ester resins, water-soluble cellulose resins, water-soluble urethane resins, water-soluble phenol resins, water-soluble amino resins, and the like. These water-soluble resins may be used alone or in combination of two or more. Among them, 1 kind selected from the group consisting of polyvinyl alcohol resins and water-soluble epoxy resins is preferably contained in view of excellent heat resistance and easy availability.
The polyvinyl alcohol resin may be modified polyvinyl alcohol resins such as carboxyl-modified polyvinyl alcohol, acetoacetyl-modified polyvinyl alcohol, hydroxymethyl-modified polyvinyl alcohol, and amino-modified polyvinyl alcohol, in addition to partially saponified polyvinyl alcohol and fully saponified polyvinyl alcohol. In addition, a commercially available polyvinyl alcohol resin can be used. Examples of such commercial products include "PVA-403" which is a partially saponified polyvinyl alcohol sold by Kuraray, and "KL-506" and "KL-318" which are carboxyl-modified partially saponified polyvinyl alcohols, and "Z-100", "Z-200", "Z-300" which are acetoacetyl-modified partially saponified polyvinyl alcohols sold by Japanese synthetic chemical Co., ltd.
As the water-soluble epoxy resin, there is exemplified a polyamide epoxy resin obtained by reacting epichlorohydrin with a polyamide polyamine (obtained by reacting a polyalkylene polyamine such as diethylenetriamine and triethylenetetramine with a dicarboxylic acid such as adipic acid). As commercial products of the polyamide epoxy Resin, "Sumirez Resin650" (manufactured by the chemical industry of Valida Co., ltd.), "Sumirez Resin675" (manufactured by the chemical industry of Valida Co., ltd.), "WS-525" (manufactured by the PMC Co., ltd.), etc. are mentioned.
The content of the water-soluble resin in the curable composition (1) is preferably 85 mass% or more, more preferably 90 mass% or more, and still more preferably 95 mass% or more, based on the mass of the solid content of the curable composition (1). The solid content of the curable composition (1) may be all the water-soluble resin (i.e., 100 mass%). In the present invention, the water-soluble resin means a resin in which 3 parts by mass or more of the resin is dissolved or uniformly dispersed in water. The term uniformly dispersed herein means that no precipitate is generated when left to stand for 24 hours. The solid content of the curable composition (1) refers to the total amount of the components remaining after the solvent is removed from the curable composition (1) when the curable composition (1) contains the solvent.
The curable composition (1) preferably contains a solvent in view of good coatability and handleability when producing a cured product of the curable composition (1). Examples of the solvent in the curable composition (1) include water or a mixed solvent of water and a hydrophilic organic solvent (for example, an alcohol solvent, an ether solvent, an ester solvent, etc.). When the curable composition (1) contains a solvent, the solid content thereof is preferably 1 to 30% by mass, more preferably 2 to 10% by mass.
The curable composition (1) may contain additives such as stabilizers, antioxidants, antistatic agents, ultraviolet absorbers, surface regulators, and crosslinking agents, as required. The additives may be used singly or in combination of two or more. The content of the additive is preferably about 0.1 to 10 mass% based on the mass of the solid content of the curable composition (1).
The curable composition (1) can be prepared by dissolving a water-soluble resin and, if necessary, additives or the like in a solvent. The 1 st protective layer can be obtained by applying the curable composition (1) to one surface of the polarizer and drying the solvent to remove the solvent, thereby curing the curable composition (1).
In the polarizing film of the present invention, the thickness of the 1 st protective layer may be appropriately determined depending on the kind of the water-soluble resin used, the composition of the curable composition constituting the 2 nd protective layer, the thickness of the 2 nd protective layer, the envisaged use environment, etc., and is preferably 0.1 to 10. Mu.m, more preferably 0.3 to 2. Mu.m. When the thickness of the 1 st protective layer is within the above range, it is possible to achieve thinning of the polarizing film while effectively suppressing diffusion of the dichroic dye from the polarizer.
In the present invention, the 2 nd protective layer has the following functions: when the polarizing film of the present invention is assembled to a polarizing plate or a display device via an adhesive layer, the 1 st protective layer is protected from an acid contained in the adhesive layer. In the polarizing film of the present invention, the 1 st protective layer mainly formed of a water-soluble resin is provided adjacent to the polarizer, whereby the diffusion of the normally insoluble dichroic dye out of the polarizer is suppressed, and the 2 nd protective layer for protecting the 1 st protective layer from the acid and water is further provided on the 1 st protective layer, whereby a polarizing film excellent in acid resistance, heat resistance and wet heat resistance can be realized. Further, by providing the 1 st protective layer and the 2 nd protective layer in this order, the 1 st protective layer and the 2 nd protective layer can exert their effects in cooperation, and thus the thickness of each protective layer can be made thinner, which is also advantageous in obtaining a thin polarizing film.
In the present invention, the polymerizable compound contained in the curable composition (2) for forming the 2 nd protective layer is a compound having at least one polymerizable group. Here, the polymerizable group means a group capable of participating in a polymerization reaction by a living radical, an acid, or the like generated by a polymerization initiator.
From the viewpoint of simplification of the process, the polymerizable compound contained in the curable composition (2) is preferably an active energy ray-curable polymerizable compound. Examples of the active energy ray-curable polymerizable compound include: a (meth) acrylate compound such as a multifunctional (meth) acrylate compound; urethane (meth) acrylate compounds such as multifunctional urethane (meth) acrylate compounds; epoxy (meth) acrylate compounds such as multifunctional epoxy (meth) acrylate compounds; a radical polymerizable compound such as a carboxyl group-modified epoxy (meth) acrylate compound and a polyester (meth) acrylate compound, and a cationic polymerizable compound such as an epoxy compound having an epoxy group, an oxetane compound having an oxetane group, and a vinyl compound. Since the cationically polymerizable compound generally tends to have high acid resistance, the curable composition (2) preferably contains the cationically polymerizable compound as the polymerizable compound. These polymerizable compounds may be used alone or in combination of two or more. The curable composition (2) may contain a cationically polymerizable compound and a radically polymerizable compound as the polymerizable compound. The radical polymerizable compound is, for example, a compound capable of initiating a polymerization reaction by using radical species generated by a photo radical polymerization initiator by irradiation of light.
From the viewpoint of ensuring high acid resistance, the curable composition (2) preferably contains a polymerizable compound having a cyclic ether structure as the polymerizable compound. Examples of the cyclic ether structure include an oxirane ring, an oxetane ring, a tetrahydrofuran ring, and a tetrahydropyran ring. Among them, from the viewpoint of achieving acid resistance and high heat resistance and moist heat resistance, the curable composition (2) preferably contains a polymerizable compound having a cyclic ether structure having 2 to 4 carbon atoms as the polymerizable compound, and more preferably contains an oxetane compound having an oxetanyl group as the polymerizable compound.
The oxetane compound having an oxetanyl group is a compound having 1 or more oxetanyl groups (oxetane rings) in the molecule, and may be any of aliphatic compounds, alicyclic compounds and aromatic compounds. Examples of oxetane compounds having 1 oxetanyl group include 3-ethyl-3-hydroxymethyl oxetane, 2-ethylhexyl oxetane, 3-ethyl-3- (phenoxymethyl) oxetane, and 3- (cyclohexyloxy) methyl-3-ethyl oxetane. Examples of oxetane compounds having two or more oxetanes include 1, 4-bis [ { (3-ethyloxetan-3-yl) methoxy } methyl ] benzene (also referred to as xylylene dioxetane) and bis (3-ethyl-3-oxetanylmethyl) ether. These oxetane compounds may be used alone or in combination of two or more.
In a preferred embodiment, the curable composition (2) contains an oxetane compound having two or more oxetanes in the molecule (hereinafter, also referred to as "oxetane compound (a)"). By containing the oxetane compound (a), a cured product having a high crosslinking density and a high density can be obtained, and in combination with the 1 st protective layer, the diffusion of the dichroic dye from the polarizer can be effectively suppressed, and a polarizing film having less possibility of occurrence of a change with time in optical performance can be obtained.
The content of the oxetane compound (a) may be, for example, 10 parts by mass or more, preferably 30 parts by mass or more, more preferably 40 parts by mass or more, still more preferably 45 parts by mass or more, and particularly preferably 50 parts by mass or more, relative to 100 parts by mass of the total amount of all the polymerizable compounds contained in the curable composition (2). When the content of the oxetane compound (a) is equal to or higher than the lower limit, the protective layer is more excellent in heat resistance and moist heat resistance, and therefore, in combination with the 1 st protective layer, the acid resistance, heat resistance and moist heat resistance of the polarizing film can be effectively improved.
This makes it possible to obtain a polarizing film which is less likely to undergo a change with time in optical performance, and to make each protective layer thinner. The content of the oxetane compound (a) is preferably 90 parts by mass or less, more preferably 85 parts by mass or less, and still more preferably 80 parts by mass or less, based on 100 parts by mass of the total amount of all polymerizable compounds contained in the curable composition (2). The content of the oxetane compound (a) may be a combination of these lower limit values and upper limit values, and may be preferably 30 to 90 parts by mass, more preferably 40 to 85 parts by mass, relative to 100 parts by mass of the total amount of all polymerizable compounds contained in the curable composition (2).
The content of the oxetane compound (a) is, for example, 25 parts by mass or more, preferably 35 parts by mass or more, more preferably 40 parts by mass or more, and further, 90 parts by mass or less, preferably 85 parts by mass or less, based on 100 parts by mass of the total amount of the curable composition (2).
The curable composition (2) preferably contains an epoxy compound as a polymerizable compound in addition to the oxetane compound (a). The epoxy compound is preferably at least one selected from (B1) an aliphatic epoxy compound having 2 or more epoxy groups (hereinafter, also referred to as "aliphatic epoxy compound (B1)"), (B2) an alicyclic epoxy compound having 2 or more epoxy groups (hereinafter, also referred to as "alicyclic epoxy compound (B2)"), and (B3) an aromatic epoxy compound having 1 or more aromatic rings (hereinafter, also referred to as "aromatic epoxy compound (B3)").
The aliphatic epoxy compound (B1) is a compound having at least 2 or more epoxy rings bonded to aliphatic carbon atoms in the molecule.
Examples of the aliphatic carbon atom in the aliphatic epoxy compound (B1) include an alkylene group having 1 to 15 carbon atoms, which may be linear or branched, and a methylene group constituting the alkylene group may be replaced with an oxygen atom.
Examples of the aliphatic epoxy compound (B1) include: 2-functional epoxy compounds such as 1, 4-butanediol diglycidyl ether, 1, 6-hexanediol diglycidyl ether, cyclohexanedimethanol diglycidyl ether, and neopentyl glycol diglycidyl ether; and epoxy compounds having 3 or more functions such as trimethylolpropane triglycidyl ether and pentaerythritol tetraglycidyl ether.
When the aliphatic epoxy compound (B1) is contained, it is preferably a 2-functional epoxy compound having 2 oxirane rings bonded to aliphatic carbon atoms in the molecule (also referred to as an aliphatic diepoxy compound), and more preferably an aliphatic diepoxy compound represented by the formula (I). The curable composition (2) can be easily applied with low viscosity by containing the aliphatic diepoxy compound represented by the formula (I) as the aliphatic epoxy compound (B1).
In the formula (I), Z represents an alkylene group having 1 to 9 carbon atoms, an alkylidene group having 3 or 4 carbon atoms, a divalent alicyclic hydrocarbon group, or a group represented by the formula-C m H 2m -Z 1 -C n H 2n -a divalent group represented. -Z 1 -represents-O-, -CO-O-, -O-CO-, -SO 2 -, -SO-or CO-, m and n each independently represent an integer of 1 or more. Wherein the sum of m and n is 9 or less.
The divalent alicyclic hydrocarbon group may be, for example, a divalent alicyclic hydrocarbon group having 4 to 8 carbon atoms, and examples thereof include a divalent residue represented by the following formula (I-1).
Specific examples of the compound represented by the formula (I) include diglycidyl ethers of alkane diols; diglycidyl ethers of oligoalkylene glycols having a repeat number of about 4; diglycidyl ethers of alicyclic diols, and the like.
Examples of the diols (diols) capable of forming the compound represented by the above formula (I) include alkane diols such as ethylene glycol, propylene glycol, 1, 3-propane diol, 2-methyl-1, 3-propane diol, 2-butyl-2-ethyl-1, 3-propane diol, 1, 4-butanediol, neopentyl glycol, 3-methyl-2, 4-pentanediol, 1, 5-pentanediol, 3-methyl-1, 5-pentanediol, 2-methyl-2, 4-pentanediol, 2, 4-diethyl-1, 5-pentanediol, 1, 6-hexanediol, 1, 7-heptanediol, 3, 5-heptanediol, 1, 8-octanediol, 2-methyl-1, 8-octanediol, and 1, 9-nonanediol;
an oligoalkylene glycol such as diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, etc.;
alicyclic diols such as cyclohexanediol and cyclohexanedimethanol.
In the present invention, the aliphatic epoxy compound (B1) is preferably 1, 4-butanediol diglycidyl ether, 1, 6-hexanediol diglycidyl ether or neopentyl glycol diglycidyl ether from the viewpoint of being able to form a curable composition (2) having a low viscosity and being easy to apply. From the viewpoint of maintaining optical properties, 1, 6-hexanediol diglycidyl ether and pentaerythritol polyglycidyl ether are preferable. The aliphatic epoxy compound (B1) may be used alone or in combination of two or more kinds.
When the curable composition (2) contains the aliphatic epoxy compound (B1), the content of the aliphatic epoxy compound (B1) may be, for example, 1 to 95 parts by mass, preferably 1 to 90 parts by mass, more preferably 1 to 40 parts by mass, still more preferably 3 to 30 parts by mass, particularly preferably 5 to 20 parts by mass, and even more preferably 7 to 15 parts by mass, based on 100 parts by mass of the total amount of all the polymerizable compounds contained in the curable composition (2).
When the content of the aliphatic epoxy compound (B1) is within the above range, the curable composition (2) has low viscosity, and a composition which is easy to apply can be produced.
The alicyclic epoxy compound (B2) is a compound having 2 or more epoxy groups bonded to an alicyclic ring in the molecule. The term "epoxy group bonded to an alicyclic ring" refers to a bridged oxygen atom-O-in the structure represented by the following formula (a).
In the above formula (a), m is an integer of 2 to 5.
The alicyclic epoxy compound (B2) includes a compound having the above-mentioned epoxy group bonded to an alicyclic ring and an alkylene group having 1 to 10 carbon atoms (the alkylene group may be linear or branched, and a methylene group constituting the alkylene group may be replaced with an oxygen atom or a carbonyl group).
More than 2 (CH) s of the above formula (a) are removed 2 ) m The alicyclic epoxy compound (B2) may be a compound in which a group of 1 or more hydrogen atoms is bonded to other chemical structures. (CH) 2 ) m The hydrogen atom of 1 or more of them may be appropriately substituted with a linear alkyl group such as a methyl group or an ethyl group.
Among them, from the viewpoint of the glass transition temperature of the cured product becoming high, alicyclic epoxy compounds having a cyclopentane structure [ structure of m=3 in the above formula (a) ] and a cyclohexane structure [ structure of m=4 in the above formula (a) ] are preferable, and alicyclic diepoxy compounds represented by the formula (II) are more preferable. The curable composition (2) contains an alicyclic diepoxy compound represented by the formula (II) as the compound (B2), whereby the glass transition temperature of the cured product layer (the 2 nd protective layer) after curing of the curable composition (2) increases, and the diffusion of the pigment at high temperature can be suppressed.
In the formula (II), R 1 R is R 2 Each independently represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, and when the number of carbon atoms of the alkyl group is 3 or more, the alkyl group may have an alicyclic structure. The alkyl group having 1 to 6 carbon atoms may be a straight chain or a straight chainExamples of the branched alkyl group include an alkyl group having an alicyclic structure, such as cyclopropyl, cyclobutyl, and cyclopentyl.
In the formula (II), X represents an oxygen atom, an alkanediyl group having 1 to 6 carbon atoms, or a divalent group represented by any one of the following formulas (IIa) to (IId).
Examples of the alkanediyl group having 1 to 6 carbon atoms include methylene, propane-1, 2-diyl and the like.
In the case where X in the formula (II) is a divalent group represented by any one of the formulas (IIa) to (IId), Y in the formulas 1 ~Y 4 Each independently represents an alkanediyl group having 1 to 20 carbon atoms, and when the alkanediyl group has 3 or more carbon atoms, the alkanediyl group may have an alicyclic structure.
a and b each independently represent an integer of 0 to 20.
Examples of the compounds represented by the formula (II) include the following compounds A to G. The chemical formulas a to G shown in the following paragraphs correspond to the compounds a to G, respectively.
A:3, 4-epoxycyclohexylmethyl 3, 4-epoxycyclohexane carboxylate
B:3, 4-epoxy-6-methylcyclohexylmethyl 3, 4-epoxy-6-methylcyclohexanecarboxylic acid
C: ethylene bis (3, 4-epoxycyclohexane carboxylate)
D: bis (3, 4-epoxycyclohexylmethyl) adipate
E: bis (3, 4-epoxy-6-methylcyclohexylmethyl) adipate
F: diethylene glycol bis (3, 4-epoxycyclohexylmethyl ether)
G: ethylene glycol bis (3, 4-epoxycyclohexylmethyl ether)
In the present invention, 3, 4-epoxycyclohexylmethyl 3, 4-epoxycyclohexane carboxylate is more preferable as the alicyclic epoxy compound (B2) from the viewpoint of easy availability. In addition, from the viewpoint of effectively suppressing the diffusion of the dye, a 1, 2-epoxy-4- (2-oxiranyl) cyclohexane adduct of 2, 2-bis (hydroxymethyl) -1-butanol is preferable. The alicyclic epoxy compound (B2) may be 1 alicyclic epoxy compound alone or a plurality of alicyclic epoxy compounds may be used in combination.
When the curable composition (2) contains the alicyclic epoxy compound (B2), the content of the alicyclic epoxy compound (B2) is preferably 1 to 90 parts by mass, more preferably 1 to 80 parts by mass, still more preferably 3 to 70 parts by mass, and still more preferably 3 to 60 parts by mass, based on 100 parts by mass of the total amount of all the polymerizable compounds contained in the curable composition (2). When the content of the alicyclic epoxy compound (B2) is within the above range, curing by irradiation with active energy rays such as ultraviolet rays proceeds rapidly, and a cured product layer (protective layer 2) excellent in heat resistance and moist heat resistance and sufficient in hardness can be formed.
The aromatic epoxy compound (B3) is a compound having 1 or more aromatic rings in the molecule, and examples thereof include the following.
Mono-and polyglycidyl ethers of phenols having at least one aromatic ring such as cresol and butylphenol, or alkylene oxide adducts thereof, for example, glycidyl ethers of bisphenol a, bisphenol F, or compounds obtained by adding alkylene oxide to them, and epoxy novolacs;
glycidyl ethers of aromatic compounds having 2 or more phenolic hydroxyl groups such as resorcinol, hydroquinone and catechol;
mono/polyglycidyl etherate of aromatic compounds having more than 2 alcoholic hydroxyl groups such as xylylene glycol, and xylylene glycol;
glycidyl esters of polybasic acid aromatic compounds having 2 or more carboxylic acids such as phthalic acid, terephthalic acid, and trimellitic acid;
glycidyl esters of benzoic acid compounds such as benzoic acid, toluic acid, naphthoic acid, and the like;
epoxide of phenyl ethylene oxide or divinylbenzene, and the like.
When the aromatic epoxy compound (B3) is contained, it is preferable that at least one member selected from the group consisting of glycidyl ethers of phenols, glycidyl ethers of aromatic compounds having two or more alcoholic hydroxyl groups, glycidyl ethers of polyhydric phenols, glycidyl esters of benzoic acids, glycidyl esters of polybasic acids, and epoxides of phenyl ethylene oxide or divinylbenzene is contained from the viewpoint of lowering the viscosity of the curable composition (2).
In addition, from the viewpoint of improving the curability of the curable composition (2), the aromatic epoxy compound (B3) is preferably a compound having an epoxy equivalent of 80 to 500.
As the aromatic epoxy compound (B3), 1 kind of aromatic epoxy compound may be used alone, or a plurality of kinds may be used in combination.
As the aromatic epoxy compound (B3), commercially available ones can be used, and examples thereof include Denacol EX-121, denacol EX-141, denacol EX-142, denacol EX-145, denacol EX-146, denacol EX-147, denacol EX-201, denacol EX-203, denacol EX-711, denacol EX-721, on Court EX-1020, on Court EX-1030, on Court EX-1040, on Court EX-1050, on Court EX-1051, on Court EX-1010, on Court EX-1011, on Court 1012 (the above is manufactured by Nagase ChemteX Co., ltd.); OGSOL PG-100, OGSOL EG-200, OGSOL EG-210, OGSOL EG-250 (manufactured by Osaka gas chemical Co., ltd.); HP4032 and HP4032D, HP4700 (the above are manufactured by DIC Co.); ESN-475V (manufactured by Nippon Kagaku Co., ltd.); epikote YX8800, jER828EL (mitsubishi chemical company); mar proof G-0105SA, mar proof G-0130SP (manufactured by Nitro Co.); epicenter N-665, epicenter HP-7200 (DIC Co., ltd.); EOCN-1020, EOCN-102S, EOCN-103S, EOCN-104S, XD-1000, NC-3000, EPPN-501H, EPPN-501HY, EPPN-502H, NC-7000L (manufactured by Japanese chemical Co., ltd.); adeka Glycirol ED-501, adeka Glycirol ED-502, adeka Glycirol ED-509, adeka Glycirol ED-529, adeka Resin EP-4000, adeka Resin EP-4005, adeka Resin EP-4100, adeka Resin EP-4901 (made by ADEKA Co., ltd.); TECHMORE VG-3101L, EPOX-MKR, EPOX-MKR151 (the above is manufactured by Printec Co.).
When the curable composition (2) contains the aromatic epoxy compound (B3), the curable composition (2) becomes a hydrophobic resin, and thus the obtained cured product layer (the 2 nd protective layer) also becomes hydrophobic. Therefore, invasion of moisture from the outside under high temperature and high humidity is prevented, and movement of the dichroic dye contained in the polarizer can be effectively suppressed.
When the curable composition (2) contains the aromatic epoxy compound (B3), the content of the aromatic epoxy compound (B3) is preferably 1 to 70 parts by mass, more preferably 5 to 60 parts by mass, still more preferably 7 to 55 parts by mass, and particularly preferably 10 to 50 parts by mass, based on 100 parts by mass of the total amount of all the polymerizable compounds contained in the curable composition (2). When the content of the aromatic epoxy compound (B3) is within the above range, the hydrophobicity of the 2 nd protective layer can be improved, and the diffusion of the dichromatic pigment out of the polarizer under high-temperature and high-humidity conditions can be more effectively suppressed.
The content of the polymerizable compound contained in the curable composition (2) is preferably 80 to 100 parts by mass, more preferably 90 to 99.5 parts by mass, and even more preferably 95 to 99 parts by mass, relative to 100 parts by mass of the total mass of the curable composition (2). When the content of the polymerizable compound is within the above range, a protective layer excellent in acid resistance and excellent in effect of preventing the dichroic dye from diffusing out of the polarizer can be obtained.
The curable composition (2) preferably contains a polymerization initiator for initiating polymerization. The polymerization initiator may be a photopolymerization initiator (e.g., a photo-cationic polymerization initiator, a photo-radical polymerization initiator) or a thermal polymerization initiator. For example, when the curable composition (2) contains the oxetane compound (a), the epoxy compound (B), or the like as the polymerizable compound, it is preferable to use a photo-cationic polymerization initiator as the polymerization initiator.
The photo-cation polymerization initiator is a polymerization initiator that generates a cation species or a lewis acid by irradiation with active energy rays such as visible rays, ultraviolet rays, X-rays, or electron rays, and initiates polymerization of a cationically polymerizable compound. The photo-cation polymerization initiator exhibits a catalytic action under light, and therefore is excellent in storage stability and handleability even when mixed with a polymerizable compound. Examples of the compound that generates a cationic species or a lewis acid upon irradiation with active energy rays include an onium salt such as an aromatic iodonium salt or an aromatic sulfonium salt, an aromatic diazonium salt, and an iron-aromatic hydrocarbon complex.
The aromatic iodonium salt is a compound having a diaryliodonium cation, and as the cation, diphenyliodonium cation is typically exemplified.
The aromatic sulfonium salt is a compound having a triarylsulfonium cation, and as the cation, triphenylsulfonium cation, 4' -bis (diphenylsulfonium) diphenyl sulfide cation, and the like are typically exemplified. The aromatic diazonium salt is a compound having a diazonium cation, and as the cation, a benzene diazonium cation is typically exemplified. In addition, the iron-aromatic hydrocarbon complex is typically a cyclopentadienyl iron (II) aromatic hydrocarbon cation complex salt.
The cations and anions (anions) shown above constitute the photo-cationic polymerization initiator in pairs. Examples of the anions constituting the photo-cationic polymerization initiator include specific phosphorus anions [ (Rf) n PF 6-n ] - Hexafluorophosphate anion PF 6 - Hexafluoroantimonate anions SbF 6 - Pentafluorohydroxy antimonate anions SbF 5 (OH) - Hexafluoroarsenate anion AsF 6 - Tetrafluoroborate anions BF 4 - Tetrakis (pentafluorophenyl) borate anion B (C) 6 F 5 ) 4 - Etc. Among them, the photo cation polymerization initiator is preferably a special phosphorus anion [ (Rf) from the viewpoint of curability of the polymerizable compound and safety of the obtained 2 nd protective layer n PF 6-n ] - Hexafluorophosphate anion PF 6 -
The photo cation polymerization initiator may be used alone or in combination of a plurality of different types. Among them, aromatic sulfonium salts are preferable because they have ultraviolet absorption characteristics even in a wavelength region around 300nm, and therefore can provide cured products having excellent curability and good mechanical strength and adhesive strength.
The content of the polymerization initiator in the curable composition (2) is usually 0.5 to 10 parts by mass, preferably 6 parts by mass or less, more preferably 3 parts by mass or less, per 100 parts by mass of the polymerizable compound. When the content of the polymerization initiator is within the above range, the polymerizable compound can be sufficiently cured, and a cured product layer composed of the obtained cured product can be provided with high mechanical strength and adhesive strength.
In the present invention, the curable composition (2) may contain additives commonly used in curable compositions, if necessary. Examples of such additives include ion capturing agents, antioxidants, chain transfer agents, polymerization accelerators (polyols, etc.), sensitizers, sensitization aids, light stabilizers, tackifiers, thermoplastic resins, fillers, flow control agents, plasticizers, antifoaming agents, leveling agents, silane coupling agents, pigments, antistatic agents, ultraviolet absorbers, and the like.
Examples of the sensitizer include photosensitizers. The photosensitizing agent is a compound that exhibits a maximum absorption at a wavelength longer than the maximum absorption wavelength exhibited by the photo-cationic polymerization initiator and promotes the polymerization initiation reaction based on the photo-cationic polymerization initiator. The photosensitizing aid is a compound that further promotes the action of the photosensitizing agent. Such a photosensitizing agent and a photosensitizing auxiliary agent are preferably blended depending on the kind of the protective film. By blending these photosensitizers and photosensitizing auxiliaries, a cured product having desired properties can be formed even when a film having low UV transmittance is used.
The photosensitizing agent is preferably a compound exhibiting a great absorption of light having a wavelength longer than 380nm, for example. Examples of the photosensitizing agent include anthracene compounds described below.
9, 10-dimethoxy anthracene,
9, 10-diethoxy anthracene,
9, 10-dipropoxyanthracene,
9, 10-diisopropylanthracene,
9, 10-dibutoxyanthracene,
9, 10-Dipentoxy-anthracene,
9, 10-Dihexyloxy-anthracene,
9, 10-bis (2-methoxyethoxy) anthracene,
9, 10-bis (2-ethoxyethoxy) anthracene,
9, 10-bis (2-butoxyethoxy) anthracene,
9, 10-bis (3-butoxypropoxy) anthracene,
2-methyl-or 2-ethyl-9, 10-dimethoxy anthracene,
2-methyl-or 2-ethyl-9, 10-diethoxyanthracene,
2-methyl-or 2-ethyl-9, 10-dipropoxyanthracene,
2-methyl-or 2-ethyl-9, 10-diisopropyloxy-anthracene,
2-methyl-or 2-ethyl-9, 10-dibutoxyanthracene,
2-methyl-or 2-ethyl-9, 10-dipentaxanthene,
2-methyl-or 2-ethyl-9, 10-dihexyloxy anthracene.
The leveling agent is an additive having a function of adjusting the fluidity of the curable composition and making a coating film obtained by applying the composition flatter, and examples thereof include silicone-based, polyacrylate-based and perfluoroalkyl-based leveling agents such as silane coupling agents.
As the leveling agent, commercially available products can be used.
The content of the leveling agent is preferably 0.01 to 5 parts by mass, more preferably 0.05 to 3 parts by mass, per 100 parts by mass of the polymerizable compound. When the content of the leveling agent is within the above range, the 2 nd protective layer obtained tends to be smoother, and is therefore preferable.
The curable composition (2) is obtained by mixing a polymerizable compound, and if necessary, a polymerization initiator and an additive. The 2 nd protective layer may be formed by: the curable composition (2) is applied onto the 1 st protective layer, and the applied curable composition (2) is cured by irradiation with active energy rays such as ultraviolet rays and electron beams.
In the polarizing film of the present invention, the thickness of the 2 nd protective layer may be appropriately determined depending on the kind of the polymerizable compound used, the combination and amount thereof, the composition of the curable composition constituting the 1 st protective layer, the thickness of the 1 st protective layer, the envisaged use environment, etc., and is preferably 0.1 to 10. Mu.m, more preferably 0.2 to 2. Mu.m. When the thickness of the 2 nd protective layer is within the above range, the protective function of the 1 st protective layer and the function of preventing the dichroic dye from diffusing from the polarizer can be exerted, and the thickness of the polarizing film can be reduced.
The polarizer constituting the polarizing film of the present invention is a cured product of a polymerizable liquid crystal composition containing a polymerizable liquid crystal compound having at least one polymerizable group and a dichroic dye.
In the polarizing film of the present invention, the polymerizable liquid crystal compound (hereinafter also referred to as "polymerizable liquid crystal compound (a)") included in the polymerizable liquid crystal composition (hereinafter also referred to as "polymerizable liquid crystal composition (a)") forming the polarizer is a liquid crystal compound having at least one polymerizable group. Here, the polymerizable group means a group which can participate in a polymerization reaction by a living radical, an acid, or the like generated by a polymerization initiator. Examples of the polymerizable group included in the polymerizable liquid crystal compound (a) include vinyl, vinyloxy, 1-chlorovinyl, isopropenyl, 4-vinylphenyl, acryloyloxy, methacryloyloxy, oxetanyl, and oxetanyl groups. Among them, a radical polymerizable group is preferable, and acryloyloxy, methacryloyloxy, vinyl, and vinyloxy groups are more preferable, and acryloyloxy and methacryloyloxy groups are still more preferable.
In the present invention, the polymerizable liquid crystal compound (a) is preferably a compound exhibiting smectic liquid crystallinity. By using a polymerizable liquid crystal compound exhibiting smectic liquid crystallinity, a polarizer having a high alignment order can be formed. The liquid crystal state of the polymerizable liquid crystal compound (a) is a smectic phase (smectic liquid crystal state), and is more preferably a higher order smectic phase (higher order smectic liquid crystal state) from the viewpoint of enabling higher alignment order. Here, the higher order smectic phase means a smectic B phase, a smectic D phase, a smectic E phase, a smectic F phase, a smectic G phase, a smectic H phase, a smectic I phase, a smectic J phase, a smectic K phase, and a smectic L phase, and among these, a smectic B phase, a smectic F phase, and a smectic I phase are more preferable. The liquid crystal property may be a thermotropic liquid crystal or a lyotropic liquid crystal, and the thermotropic liquid crystal is preferable in view of being capable of precise film thickness control. The polymerizable liquid crystal compound (a) may be a monomer, or may be an oligomer or polymer obtained by polymerizing a polymerizable group.
The polymerizable liquid crystal compound (a) is not particularly limited as long as it is a liquid crystal compound having at least one polymerizable group, and a known polymerizable liquid crystal compound can be used, and a compound exhibiting smectic liquid crystal property is preferable. Examples of such a polymerizable liquid crystal compound include a compound represented by the following formula (A1) (hereinafter also referred to as "polymerizable liquid crystal compound (A1)").
U 1 -V 1 -W 1 -(X 1 -Y 1 -) n -X 2 -W 2 -V 2 -U 2 (A1)
In the formula (A1),
X 1 and X 2 Independently of each other, a divalent aromatic group or a divalent alicyclic hydrocarbon group, wherein a hydrogen atom contained in the divalent aromatic group or the divalent alicyclic hydrocarbon group may be substituted with a halogen atom, an alkyl group having 1 to 4 carbon atoms, a fluoroalkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a cyano group or a nitro group, and a carbon atom constituting the divalent aromatic group or the divalent alicyclic hydrocarbon group may be substituted with an oxygen atom or a sulfur atom or a nitrogen atom. Wherein X is 1 And X 2 Is a1, 4-phenylene group which may have a substituent or a cyclohexane-1, 4-diyl group which may have a substituent.
Y 1 Is a single bond or a divalent linking group.
n is 1 to 3, and when n is 2 or more,multiple X' s 1 May be the same or different from each other. X is X 2 Can be combined with a plurality of X 1 Either one or all of them may be the same or different. When n is 2 or more, a plurality of Y' s 1 May be the same or different from each other. From the viewpoint of liquid crystal property, n is preferably 2 or more.
U 1 Represents a hydrogen atom or a polymerizable group.
U 2 Represents a polymerizable group.
W 1 And W is 2 Independently of one another, a single bond or a divalent linking group.
V 1 And V 2 Independently of each other, represents an alkanediyl group having 1 to 20 carbon atoms which may have a substituent, and the-CH constituting the alkanediyl group 2 -can be replaced by-O-, -CO-, -S-or NH-.]
In the polymerizable liquid crystal compound (A1), X 1 And X 2 Independently of one another, 1, 4-phenylene which may have substituents or cyclohexane-1, 4-diyl which may have substituents, X 1 And X 2 At least 1 of (c) is a1, 4-phenylene group which may have a substituent, or a cyclohexane-1, 4-diyl group which may have a substituent, and preferably a trans-cyclohexane-1, 4-diyl group. Examples of the substituent optionally contained in the 1, 4-phenylene group which may have a substituent or the cyclohexane-1, 4-diyl group which may have a substituent include an alkyl group having 1 to 4 carbon atoms such as a methyl group, an ethyl group and a butyl group, a cyano group, a halogen atom such as a chlorine atom and a fluorine atom. Preferably unsubstituted.
In addition, from the viewpoint of easy presentation of smectic liquid crystallinity, the polymerizable liquid crystal compound (A1) is preferably a moiety represented by the formula (A1-1) in the formula (A1) [ hereinafter, referred to as a partial structure (A1-1) ]. Is of an asymmetric structure.
-(X 1 -Y 1 -) n -X 2 - (A1-1)
[ in the formula, X 1 、Y 1 、X 2 And n each represent the same meaning as described above. A kind of electronic device
As the polymerizable liquid crystal compound (A1) having an asymmetric partial structure (A1-1), for example, a compound having a structure (A1) of asymmetric structure can be usedExamples are: n is 1 and 1X 1 And X is 2 Polymerizable liquid crystal compounds (A1) having different structures from each other.
In addition, there may be mentioned:
a polymerizable liquid crystal compound (A1) having n of 2 and 2Y' s 1 Compounds of the same structure as each other, which are 2X 1 The same structure as each other and 1X 2 With the above 2X 1 Different structures;
a polymerizable liquid crystal compound (A1) having n of 2 and 2Y' s 1 Compounds of the same structure as each other, which are 2X 1 Is bonded to W 1 X of (2) 1 With another X 1 And X 2 Different in structure and of another X 1 And X is 2 The same structure as each other.
Further, there may be mentioned:
a polymerizable liquid crystal compound (A1) having n of 3 and 3Y 1 Compounds of the same structure as each other, which are 3X 1 And 1X 2 Any one of them is different from the other 3.
Y 1 preferably-CH 2 CH 2 -、-CH 2 O-、-CH 2 CH 2 O-, -COO-, -OCOO-, a single bond, -N=N-, -CR a =CR b -、-C≡C-、-CR a =n-or-CO-NR a -。R a And R is b Independently of each other, represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. Y is Y 1 More preferably-CH 2 CH 2 -, -COO-or a single bond, in which plural Y's are present 1 In the case of (2), with X 2 Bonded Y 1 More preferably-CH 2 CH 2 -or-CH 2 O-. At X 1 And X 2 In the case of the same structure, it is preferable that there are at least 2Y's having different bonding modes 1 . In the presence of a plurality of Y's having different bonding modes 1 In the case of (2), the structure is asymmetric, and therefore, the smectic liquid crystallinity tends to be easily exhibited.
U 2 Is a polymerizable group. U (U) 1 The hydrogen atom or the polymerizable group is preferably a polymerizable group. Preferably U 1 And U 2 All are polymerizable groups, preferably all are radically polymerizable groups. Examples of the polymerizable group include the same groups as those described above as the polymerizable groups of the polymerizable liquid crystal compound (a). U (U) 1 Represented polymerizable group and U 2 The polymerizable groups represented may be different from each other, but are preferably the same kind of groups. The polymerizable group may be polymerized or unpolymerized, but is preferably unpolymerized.
As V 1 V (V) 2 Examples of the alkanediyl group include methylene, ethylene, propane-1, 3-diyl, butane-1, 4-diyl, pentane-1, 5-diyl, hexane-1, 6-diyl, heptane-1, 7-diyl, octane-1, 8-diyl, decane-1, 10-diyl, tetradecane-1, 14-diyl and eicosane-1, 20-diyl. V (V) 1 V (V) 2 The alkanediyl group having 2 to 12 carbon atoms is preferable, and the alkanediyl group having 6 to 12 carbon atoms is more preferable.
Examples of the substituent optionally contained in the alkanediyl group include a cyano group and a halogen atom, and the alkanediyl group is preferably unsubstituted, more preferably unsubstituted, linear alkanediyl group.
W 1 W and W 2 Independent of each other, is preferably a single bond, -O- -S-, -COO-or OCOO-, more preferably a single bond or-O-.
The polymerizable liquid crystal compound (a) is not particularly limited as long as it is a polymerizable liquid crystal compound having at least one polymerizable group, and a known polymerizable liquid crystal compound may be used, and preferably exhibits smectic liquid crystallinity, and as a structure that tends to exhibit smectic liquid crystallinity, a molecular structure having asymmetry in the molecular structure is preferable, specifically, a polymerizable liquid crystal compound having the following partial structures (a-a) to (a-i) is more preferable, and a polymerizable liquid crystal compound exhibiting smectic liquid crystallinity is more preferable. From the viewpoint of easily exhibiting high-order smectic liquid crystal property, it is more preferable to have a partial structure of (A-a), (A-b) or (A-c). In the following (A-a) to (A-i), the term "means a bond (single bond).
Specific examples of the polymerizable liquid crystal compound (A) include compounds represented by the formulae (A-1) to (A-25). When the polymerizable liquid crystal compound (a) has a cyclohexane-1, 4-diyl group, the cyclohexane-1, 4-diyl group is preferably a trans-form.
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Of these, at least 1 selected from the group consisting of the compounds represented by the formula (A-2), the formula (A-3), the formula (A-4), the formula (A-5), the formula (A-6), the formula (A-7), the formula (A-8), the formula (A-13), the formula (A-14), the formula (A-15), the formula (A-16) and the formula (A-17) is preferable. As the polymerizable liquid crystal compound (a), 1 kind may be used alone, or 2 or more kinds may be used in combination.
The polymerizable liquid crystal compound (A) can be produced by a known method described in, for example, recl.Trav.Chim.Pays-Bas,115,321-328 (1996) of Lub et al, or Japanese patent No. 4719156.
In the present invention, the polymerizable liquid crystal composition (a) may contain other polymerizable liquid crystal compounds than the polymerizable liquid crystal compound (a), and the proportion of the polymerizable liquid crystal compound (a) relative to the total mass of all the polymerizable liquid crystal compounds contained in the polymerizable liquid crystal composition (a) is preferably 51 mass% or more, more preferably 70 mass% or more, and further preferably 90 mass% or more, from the viewpoint of obtaining a polarizing film having a high alignment order.
In the case where the polymerizable liquid crystal composition (a) contains 2 or more polymerizable liquid crystal compounds (a), at least 1 of them may be the polymerizable liquid crystal compound (A1), or all of them may be the polymerizable liquid crystal compound (A1). By combining a plurality of polymerizable liquid crystal compounds, liquid crystallinity may be temporarily maintained even at a temperature equal to or lower than the liquid crystal-crystalline phase transition temperature.
The content of the polymerizable liquid crystal compound in the polymerizable liquid crystal composition (a) is preferably 40 to 99.9% by mass, more preferably 60 to 99% by mass, and even more preferably 70 to 99% by mass, based on the solid content of the polymerizable liquid crystal composition (a). When the content of the polymerizable liquid crystal compound is within the above range, the orientation of the polymerizable liquid crystal compound tends to be high. In the present specification, the solid content of the polymerizable liquid crystal composition (a) refers to the total amount of the components remaining after the solvent is removed from the polymerizable liquid crystal composition (a).
In the present invention, the polymerizable liquid crystal composition (a) forming the polarizer contains a dichroic dye. Here, the dichromatic dye is a dye having a property that the absorbance in the long axis direction of the molecule is different from the absorbance in the short axis direction. The dichroic dye that can be used in the present invention is not particularly limited as long as it has the above properties, and may be a dye or a pigment. In addition, 2 or more dyes or pigments may be used in combination, respectively, or may be used in combination.
The dichroic dye is preferably an organic dichroic dye, and more preferably has a maximum absorption wavelength (lambda) in the range of 300 to 700nm MAX ) Is a pigment of (a) a pigment of (b). Examples of such a dichroic dye include acridine dye, oxazine dye, cyanine dye, naphthalene dye, azo dye, and anthraquinone dye.
Examples of the azo dye include monoazo dye, disazo dye, trisazo dye, tetrazo dye, stilbene azo dye, and the like, and preferably the disazo dye and trisazo dye include, for example, a compound represented by the formula (I) (hereinafter, also referred to as "compound (I)").
K 1 (-N=N-K 2 ) p -N=N-K 3 (I)
[ in formula (I), K 1 K is as follows 3 Independently of each other, represents a phenyl group which may have a substituent, a naphthyl group which may have a substituent, or a monovalent heterocyclic group which may have a substituent. K (K) 2 Represents p-phenylene which may have a substituent, naphthalene-1, 4-diyl which may have a substituent, or a divalent heterocyclic group which may have a substituent. p represents an integer of 1 to 4. When p is an integer of 2 or more, a plurality of K 2 May be the same or different from each other. In the range where the visible light region exhibits absorption, the-n=n-bond may be replaced by a-c=c-, -COO-, -NHCO-, -n=ch-bond.]
Examples of the monovalent heterocyclic group include a group obtained by removing 1 hydrogen atom from a heterocyclic compound such as quinoline, thiazole, benzothiazole, thienothiazole, imidazole, benzimidazole, oxazole, and benzoxazole. Examples of the divalent heterocyclic group include a group obtained by removing 2 hydrogen atoms from the heterocyclic compound.
As K 1 K is as follows 3 Phenyl, naphthyl and monovalent heterocyclic groups, K 2 The substituent optionally contained in the p-phenylene group, naphthalene-1, 4-diyl group and divalent heterocyclic group in (a) may be an alkyl group having 1 to 4 carbon atoms; alkoxy groups having 1 to 4 carbon atoms such as methoxy, ethoxy and butoxy groups; fluorinated alkyl groups having 1 to 4 carbon atoms such as trifluoromethyl; cyano group; a nitro group; a halogen atom; substituted or unsubstituted amino groups such as amino, diethylamino and pyrrolidinyl (substituted amino means amino groups having 1 or 2 alkyl groups having 1 to 6 carbon atoms or amino groups having 2 substituted alkyl groups bonded to each other to form alkanediyl groups having 2 to 8 carbon atoms; unsubstituted amino groups are-NH) 2 . ) Etc.
Among the compounds (I), preferred are compounds represented by any one of the following formulas (I-1) to (I-8).
[ in the formulae (I-1) to (I-8),
B 1 ~B 30 independently of each other, a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a cyano group, a nitro group, a substituted or unsubstituted amino group (the substituted amino group and the unsubstituted amino group are defined as above), a chlorine atom or a trifluoromethyl group.
n1 to n4 independently represent an integer of 0 to 3.
When n1 is 2 or more, a plurality of B 2 May be the same as or different from each other,
when n2 is 2 or more, a plurality of B 6 May be the same as or different from each other,
when n3 is 2 or more, a plurality of B 9 May be the same as or different from each other,
when n4 is 2 or more, a plurality of B 14 May be the same or different from each other.]
As the anthraquinone pigment, a compound represented by the formula (I-9) is preferable.
In the formula (I-9),
R 1 ~R 8 independently of one another, represent a hydrogen atom, -R x 、-NH 2 、-NHR x 、-NR x 2 、-SR x Or a halogen atom.
R x Represents an alkyl group having 1 to 4 carbon atoms or an aryl group having 6 to 12 carbon atoms.]
As the oxazinone pigment, a compound represented by the formula (I-10) is preferable.
In the formula (I-10),
R 9 ~R 15 independently of one another, represent a hydrogen atom, -R x 、-NH 2 、-NHR x 、-NR x 2 、-SR x Or a halogen atom.
R x Represents an alkyl group having 1 to 4 carbon atoms or an aryl group having 6 to 12 carbon atoms.]
As the acridine dye, a compound represented by the formula (I-11) is preferable.
In the formula (I-11),
R 16 ~R 23 independently of one another, represent a hydrogen atom, -R x 、-NH 2 、-NHR x 、-NR x 2 、-SR x Or a halogen atom.
R x Represents an alkyl group having 1 to 4 carbon atoms or an aryl group having 6 to 12 carbon atoms.]
In the formula (I-9), the formula (I-10) and the formula (I-11), R is x Examples of the alkyl group having 1 to 6 carbon atoms include methyl, ethyl, propyl, butyl, pentyl, and hexyl groups, and examples of the aryl group having 6 to 12 carbon atoms include phenyl, toluyl, xylyl, and naphthyl groups.
As the cyanine dye, a compound represented by the formula (I-12) and a compound represented by the formula (I-13) are preferable.
In the formula (I-12),
D 1 d (D) 2 Independently of each other, a group represented by any one of the formulae (I-12 a) to (I-12 d).
n5 represents an integer of 1 to 3. ]
In the formula (I-13),
D 3 d (D) 4 Independently of each other, a group represented by any one of the formulae (I-13 a) to (1-13 h).
n6 represents an integer of 1 to 3. ]
Among these dichromatic pigments, azo pigments have high linearity and are therefore suitable for producing polarizers having excellent polarizing properties, but in polarizing films comprising high-performance polarizers, even if a very small amount of pigments diffuse out of the polarizer, the influence on the optical properties thereof becomes large. In such a polarizer, the polarizing film of the present invention, in which the 1 st protective layer which is the cured product of the specific curable composition (1) and the 2 nd protective layer which is the cured product of the curable composition (2) are laminated in this order, can also effectively suppress the diffusion (particularly, thermal diffusion and damp-heat diffusion) of the dichroic dye, and can significantly exhibit the effects of the present invention. Therefore, in one embodiment of the present invention, the dichroic dye contained in the polymerizable liquid crystal composition forming the polarizer is preferably an azo dye.
In the present invention, the weight average molecular weight of the dichroic dye is usually 300 to 2000, preferably 400 to 1000. When the weight average molecular weight of the dichroic dye is equal to or less than the upper limit, the dichroic dye in the polarizer in a state of being encapsulated by the polymerizable liquid crystal compound is likely to move, and is likely to diffuse out of the polarizer in a high-temperature environment or the like. Even in such a case, the polarizing film of the present invention in which the specific protective layer is laminated on the polarizer can effectively suppress the diffusion (particularly, thermal diffusion and damp-heat diffusion) of the dichroic dye, and can remarkably exhibit the effects of the present invention.
The content of the dichroic dye in the polymerizable liquid crystal composition (a) may be appropriately determined depending on the type of the dichroic dye used, and is preferably 0.1 to 50 parts by mass, more preferably 0.1 to 20 parts by mass, and even more preferably 0.1 to 12 parts by mass, relative to 100 parts by mass of the polymerizable liquid crystal compound. When the content of the dichroic dye is within the above range, the alignment of the polymerizable liquid crystal compound is not easily disturbed, and a polarizer having a high alignment order can be obtained.
In the present invention, the polymerizable liquid crystal composition (a) for forming a polarizer may contain a polymerization initiator. The polymerization initiator is a compound capable of initiating polymerization of the polymerizable liquid crystal compound, and is preferably a photopolymerization initiator in view of initiating polymerization under a relatively low temperature condition. Specifically, a photopolymerization initiator capable of generating a living radical or an acid by the action of light is exemplified, and among them, a photopolymerization initiator capable of generating a radical by the action of light is preferable. The polymerization initiator may be used singly or in combination of two or more.
As the photopolymerization initiator, a known photopolymerization initiator may be used, and examples of the photopolymerization initiator that generates a living radical include self-cleaving photopolymerization initiators and hydrogen-abstraction photopolymerization initiators.
As the self-cleaving photopolymerization initiator, a self-cleaving benzoin compound, acetophenone compound, hydroxyacetophenone compound, α -aminoacetophenone compound, oxime ester compound, acylphosphine oxide compound, azo compound, or the like can be used. Further, as the hydrogen abstraction type photopolymerization initiator, a hydrogen abstraction type benzophenone compound, a benzoin ether compound, a benzil ketal compound, a dibenzosuberone compound, an anthraquinone compound, a xanthone compound, a thioxanthone compound, a halogenated acetophenone compound, a dialkoxyacetophenone compound, a halogenated bisimidazole compound, a halogenated triazine compound, a triazine compound, and the like can be used.
As the photopolymerization initiator for generating an acid, iodonium salts, sulfonium salts, and the like can be used.
Among them, the reaction at low temperature is preferable from the viewpoint of preventing the dissolution of the dye, and the self-cleaving photopolymerization initiator is preferable from the viewpoint of the reaction efficiency at low temperature, and acetophenone-based compounds, hydroxyacetophenone-based compounds, α -aminoacetophenone-based compounds, and oxime ester-based compounds are particularly preferable.
Specific examples of the photopolymerization initiator include the following.
Benzoin compounds such as benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether and benzoin isobutyl ether;
hydroxyacetophenone compounds such as oligomers of 2-hydroxy-2-methyl-1-phenylpropane-1-one, 1, 2-diphenyl-2, 2-dimethoxyethane-1-one, 2-hydroxy-2-methyl-1- [4- (2-hydroxyethoxy) phenyl ] propane-1-one, 1-hydroxycyclohexylphenyl ketone and 2-hydroxy-2-methyl-1- [4- (1-methylvinyl) phenyl ] propane-1-one;
alpha-aminoacetophenone compounds such as 2-methyl-2-morpholino-1- (4-methylsulfanylphenyl) propan-1-one and 2-dimethylamino-2-benzyl-1- (4-morpholinophenyl) butan-1-one;
oxime ester compounds such as 1, 2-octanedione-1- [4- (phenylthio) -2- (O-benzoyl oxime) ], 1- [ 9-ethyl-6- (2-methylbenzoyl) -9H-carbazol-3-yl ] -ethanone-1- (O-acetyl oxime);
acyl phosphine oxide compounds such as 2,4, 6-trimethylbenzoyl diphenyl phosphine oxide and bis (2, 4, 6-trimethylbenzoyl) phenylphosphine oxide;
benzophenone compounds such as benzophenone, methyl o-benzoylbenzoate, 4-phenylbenzophenone, 4-benzoyl-4 ' -methyldiphenyl sulfide, 3', 4' -tetrakis (t-butylperoxycarbonyl) benzophenone, and 2,4, 6-trimethylbenzophenone;
Dialkoxyacetophenones such as diethoxyacetophenone;
triazine compounds such as 2, 4-bis (trichloromethyl) -6- (4-methoxyphenyl) -1,3, 5-triazine, 2, 4-bis (trichloromethyl) -6- (4-methoxynaphthyl) -1,3, 5-triazine, 2, 4-bis (trichloromethyl) -6- (4-methoxystyryl) -1,3, 5-triazine, 2, 4-bis (trichloromethyl) -6- [ 2- (5-methylfuran-2-yl) vinyl ] -1,3, 5-triazine, 2, 4-bis (trichloromethyl) -6- [ 2- (furan-2-yl) vinyl ] -1,3, 5-triazine, 2, 4-bis (trichloromethyl) -6- [ 2- (4-diethylamino-2-methylphenyl) vinyl ] -1,3, 5-triazine and 2, 4-bis (trichloromethyl) -6- [ 2- (3, 4-dimethoxyphenyl) vinyl ] -1,3, 5-triazine. The photopolymerization initiator may be appropriately selected from the above-mentioned photopolymerization initiators, for example, depending on the relationship with the polymerizable liquid crystal compound contained in the polymerizable liquid crystal composition (a).
In addition, a commercially available photopolymerization initiator may be used. Examples of the photopolymerization initiator that are commercially available include Irgacure (registered trademark) 907, 184, 651, 819, 250, 369, 379, 127, 754, OXE01, OXE02, OXE03 (manufactured by BASF corporation); omnirad BCIM, esacure 1001M, esacure KIP160 (IDM Resins b.v. company); SEIKUOL (registered trademark) BZ, Z, and BEE (manufactured by semiochemical corporation); kayacure (registered trademark) BP100 and UVI-6992 (manufactured by DOW Chemical Company), ADEKA OPTOMER SP-152, N-1717, N-1919, SP-170, ADEKA ARKLS NCI-831, ADEKA ARKLS NCI-930 (manufactured by ADEKA, inc.), TAZ-A and TAZ-PP (manufactured by Siber Hegner Co., ltd.), and TAZ-104 (manufactured by Sanwa Chemical Co., ltd.), and the like.
The content of the polymerization initiator in the polymerizable liquid crystal composition (a) for forming a polarizer is preferably 1 to 10 parts by mass, more preferably 1 to 8 parts by mass, further preferably 2 to 8 parts by mass, and particularly preferably 4 to 8 parts by mass, relative to 100 parts by mass of the polymerizable liquid crystal compound. When the content of the polymerization initiator is within the upper limit and the lower limit, the polymerization reaction of the polymerizable liquid crystal compound can be performed without greatly disturbing the alignment of the polymerizable liquid crystal compound.
In the present invention, the polymerization rate of the polymerizable liquid crystal compound is preferably 60% or more, more preferably 65% or more, and even more preferably 70% or more, from the viewpoints of line pollution and handling at the time of production.
The polymerizable liquid crystal composition (a) may further contain a photosensitizing agent. By using a photosensitizing agent, the polymerization reaction of the polymerizable liquid crystal compound can be further promoted. Examples of the photosensitizing agent include xanthone compounds such as xanthone and thioxanthone (e.g., 2, 4-diethylthioxanthone and 2-isopropylthioxanthone); anthracene compounds such as anthracene and alkoxy group-containing anthracene (e.g., dibutoxyanthracene); phenothiazine, rubrene, and the like. The photosensitizing agent may be used alone or in combination of 2 or more.
When the polymerizable liquid crystal composition (a) contains a photosensitizing agent, the content thereof may be appropriately determined according to the kind and amount of the polymerization initiator and the polymerizable liquid crystal compound, and is preferably 0.1 to 30 parts by mass, more preferably 0.5 to 10 parts by mass, and still more preferably 0.5 to 8 parts by mass, relative to 100 parts by mass of the polymerizable liquid crystal compound.
The polymerizable liquid crystal composition (a) may contain a leveling agent. The leveling agent has a function of adjusting fluidity of the polymerizable liquid crystal composition and flattening a coating film obtained by coating the polymerizable liquid crystal composition, and specifically, a surfactant is exemplified. The leveling agent in the polymerizable liquid crystal composition (a) is preferably at least 1 kind selected from the group consisting of a leveling agent containing a polyacrylate compound as a main component and a leveling agent containing a fluorine atom-containing compound as a main component. The leveling agent may be used alone or in combination of 2 or more.
Examples of leveling agents containing polyacrylate compounds as a main component include "BYK-350", "BYK-352", "BYK-353", "BYK-354", "BYK-355", "BYK-358N", "BYK-361N", "BYK-380", "BYK-381" and "BYK-392" (BYK Chemie).
Examples of leveling agents containing fluorine atoms as a main component include "MEGAFACE (registered trademark) R-08", MEGAFACE "R-30", MEGAFACE "R-90", MEGAFACE "F-410", MEGAFACE "F-411", MEGAFACE "F-443", MEGAFACE "F-445", MEGAFACE "F-470", MEGAFACE "F-471", MEGAFACE "F-477", MEGAFACE "F-479", MEGAFACE "F-482" and MEGAFACE "F-483" (DIC Co., ltd.); "Surflon (registered trademark) S-381", surflon "S-382", surflon "S-383", surflon "S-393", surflon "SC-101", surflon "SC-105", "KH-40" and "SA-100" (AGC Seimi Chemical Co., ltd.); "E1830", "E5844" (Daikin Fine Chemical Kenkyusho, k.); "EFTOP EF301", "EFTOP EF303", "EFTOP EF351" and "EFTOP EF352" (Mitsubishi Materials Electronic Chemicals Co., ltd.).
When the polymerizable liquid crystal composition (a) contains a leveling agent, the content thereof is preferably 0.05 to 5 parts by mass, more preferably 0.05 to 3 parts by mass, relative to 100 parts by mass of the polymerizable liquid crystal compound. If the content of the leveling agent is within the above range, the following tends to occur: the polymerizable liquid crystal compound is easily oriented horizontally, and unevenness is less likely to occur, so that a smoother polarizer can be obtained.
The polymerizable liquid crystal composition (a) may contain additives other than the photosensitizing agent and the leveling agent. Examples of the other additives include antioxidants, mold release agents, stabilizers, colorants such as bluing agents, flame retardants, lubricants, and the like. When the polymerizable liquid crystal composition (a) contains other additives, the content of the other additives is preferably more than 0% and 20% by mass or less, more preferably more than 0% and 10% by mass or less, relative to the solid content of the polymerizable liquid crystal composition (a).
The polymerizable liquid crystal composition (a) can be produced by a conventionally known method for producing the polymerizable liquid crystal composition (a), and is usually produced by mixing and stirring a polymerizable liquid crystal compound and a dichroic dye, and if necessary, a polymerization initiator, the above-mentioned additives, and the like.
In the polarizing film of the present invention, the polarizer is preferably a polarizer having a high orientation order. In the case of a polarizer having a high degree of orientation, bragg peaks derived from higher structures such as hexagonal phase and crystalline phase can be obtained in an X-ray diffraction measurement. The bragg peak is a peak derived from a surface periodic structure of molecular orientation. Therefore, it is preferable that the polarizer constituting the polarizing film of the present invention exhibits a bragg peak in an X-ray diffraction measurement. That is, in the polarizer constituting the polarizing film of the present invention, the polymerizable liquid crystal compound or the polymer thereof is preferably oriented in such a manner that the polarizer shows a Bragg peak in an X-ray diffraction measurement, more preferably "horizontal" in which the molecules of the polymerizable liquid crystal compound are oriented in the direction of absorbing light Orientation). In the present invention, the preferred molecular orientation has a face cycle spacing ofIs provided. The high degree of alignment order such as the bragg peak can be achieved by controlling the kind of the polymerizable liquid crystal compound to be used, the kind of the dichroic dye, the amount thereof, the kind of the polymerization initiator, the amount thereof, and the like.
In the present invention, the thickness of the polarizer may be appropriately selected according to the display device to be used, and is preferably a film of 0.1 μm or more and 5 μm or less, more preferably 0.3 μm or more and 4 μm or less, and still more preferably 0.5 μm or more and 3 μm or less. If the thickness is too small in the range, the necessary light absorption may not be obtained, and if the thickness is too large in the range, the orientation restriction force by the orientation film tends to be low, and orientation defects tend to be easily generated.
In the polarizing film of the present invention, the polarizer may be laminated on the substrate. Examples of the substrate include a glass substrate and a film substrate, and a resin film substrate is preferable from the viewpoints of flexibility and processability. Examples of the resin constituting the resin film include polyolefin such as polyethylene and polypropylene; cyclic olefin resins such as norbornene polymers; polyethylene terephthalate; a polymethacrylate; a polyacrylate; cellulose esters such as triacetyl cellulose, diacetyl cellulose, and cellulose acetate propionate; polyethylene naphthalate; a polycarbonate; polysulfone; polyether sulfone; polyether ketone; polyphenylene sulfide; polyphenylene ether; polyamides, polyamideimides, and the like. From the viewpoint of ease of obtaining, polyethylene terephthalate, polymethacrylate, cellulose ester, polyamide, polyamideimide, cyclic olefin resin or polycarbonate is preferable. Cellulose esters are products obtained by esterifying a part or all of hydroxyl groups contained in cellulose, and are readily available on the market. In addition, cellulose ester substrates are also readily available from the market. Examples of the commercially available cellulose ester base material include "Fujitac Film" (Fuji Photo Film co., ltd.); "KC8UX2M", "KC8UY" and "KC4UY" (Konica Minolta Inc.), etc. The characteristics required for the substrate vary depending on the constitution of the polarizing film, and in general, a substrate having as small a retardation as possible is preferable. Examples of the base material having as little retardation as possible include cellulose ester films having no retardation such as ZeroTAC (Konica Minolta Opto inc.) and Z-TAC (Fujifilm Corporation). The resin film may be any of stretched and unstretched, and the surface of the substrate on which the polarizer is not laminated may be subjected to a hard coat treatment, an antireflection treatment, an antistatic treatment, or the like.
In addition, the polarizer may be laminated on the substrate via an alignment film. The orientation film is preferably a photo-orientation film from the viewpoints of accuracy and quality of orientation angle, water resistance and bendability of a polarizing film including the orientation film, and the like. When the alignment film is contained, the thickness of the alignment film is preferably 10 to 5000nm, more preferably 10 to 1000nm.
The polarizing film of the present invention can be produced, for example, by a method comprising the steps of:
forming a coating film of a polymerizable liquid crystal composition (a) containing a polymerizable liquid crystal compound having at least one polymerizable group and a dichroic dye, removing a solvent from the coating film, heating to a temperature equal to or higher than a temperature at which the polymerizable liquid crystal compound changes phase to a liquid phase, cooling to change the polymerizable liquid crystal compound to a smectic phase, and polymerizing the polymerizable liquid crystal compound while maintaining the smectic phase to obtain a polarizer (hereinafter, also referred to as a "polarizer forming step");
a step of applying a curable composition (1) to one surface of the obtained polarizer, and drying and removing a solvent contained in the curable composition (1) to cure the curable composition (1) to obtain a 1 st protective layer (hereinafter, also referred to as a "1 st protective layer forming step"); the method comprises the steps of,
And a step of applying a curable composition (2) to the surface of the obtained 1 st protective layer on the opposite side to the polarizer, polymerizing and curing the polymerizable compound to obtain a 2 nd protective layer (hereinafter, also referred to as "2 nd protective layer forming step").
In the polarizer forming step, the formation of the coating film of the polymerizable liquid crystal composition (a) may be performed by, for example, coating the polymerizable liquid crystal composition (a) directly or via an alignment film described later on a substrate. In general, since a compound exhibiting smectic liquid crystallinity has a high viscosity, from the viewpoint of improving the coatability of the polymerizable liquid crystal composition (a) and facilitating formation of a polarizer, the viscosity can be adjusted by adding a solvent to the polymerizable liquid crystal composition (a) (hereinafter, a composition obtained by adding a solvent to the polymerizable liquid crystal composition is also referred to as a "polarizer-forming composition").
The solvent used in the polarizer-forming composition may be appropriately selected depending on the polymerizable liquid crystal compound used, the solubility of the dichroic dye, and the like. Specifically, examples thereof include alcohol solvents such as water, methanol, ethanol, ethylene glycol, isopropyl alcohol, propylene glycol, methyl cellosolve, butyl cellosolve, propylene glycol monomethyl ether, ester solvents such as ethyl acetate, butyl acetate, ethylene glycol methyl ether acetate, γ -butyrolactone, propylene glycol methyl ether acetate, ethyl lactate, ketone solvents such as acetone, methyl ethyl ketone, cyclopentanone, cyclohexanone, methyl amyl ketone, methyl isobutyl ketone, aliphatic hydrocarbon solvents such as pentane, hexane, heptane, aromatic hydrocarbon solvents such as toluene and xylene, nitrile solvents such as acetonitrile, ether solvents such as tetrahydrofuran and dimethoxyethane, and chlorinated hydrocarbon solvents such as chloroform and chlorobenzene. These solvents may be used singly or in combination of 2 or more. The content of the solvent is preferably 100 to 1900 parts by mass, more preferably 150 to 900 parts by mass, and even more preferably 180 to 600 parts by mass, based on 100 parts by mass of the solid content constituting the polymerizable liquid crystal composition (a).
Examples of the method of applying the polarizer-forming composition to a substrate or the like include known methods such as spin coating, extrusion, gravure coating, die coating, bar coating, coating by an applicator, and printing by a flexography.
Next, the solvent is removed by drying or the like under the condition that the polymerizable liquid crystal compound contained in the coating film obtained from the composition for forming a polarizer is not polymerized, whereby a dried coating film can be formed. Examples of the drying method include a natural drying method, a ventilation drying method, a heat drying method, and a reduced pressure drying method.
Further, in order to change the phase of the polymerizable liquid crystal compound into a liquid phase, the temperature is raised to a temperature equal to or higher than the temperature at which the polymerizable liquid crystal compound changes into a liquid phase, and then the temperature is lowered to change the polymerizable liquid crystal compound into a smectic phase (smectic liquid crystal state). The phase transition may be performed after or simultaneously with the removal of the solvent in the coating film.
The polarizer is formed as a cured layer of the polymerizable liquid crystal composition by polymerizing the polymerizable liquid crystal compound while maintaining a smectic liquid crystal state of the polymerizable liquid crystal compound. As the polymerization method, photopolymerization is preferable. In photopolymerization, the light to be irradiated to the dry coating film may be appropriately selected depending on the type of the polymerizable liquid crystal compound contained in the dry coating film (particularly, the type of the polymerizable group contained in the polymerizable liquid crystal compound), the type of the polymerization initiator, the amount thereof, and the like. Specific examples thereof include active energy rays and active electron beams of 1 or more selected from the group consisting of visible light, ultraviolet light, infrared light, X-rays, α -rays, β -rays and γ -rays. Among them, ultraviolet light is preferable in that the progress of the polymerization reaction is easily controlled, and a device widely used in the art as a photopolymerization device can be used, and the types of the polymerizable liquid crystal compound and the polymerization initiator contained in the polymerizable liquid crystal composition are preferably selected in advance so that photopolymerization can be performed by ultraviolet light. In addition, at the time of polymerization, the polymerization temperature may be controlled by performing light irradiation while cooling the dried coating film by an appropriate cooling means. If the polymerization of the polymerizable liquid crystal compound is carried out at a relatively low temperature by using such a cooling means, a polarizer can be formed appropriately even if a substrate having relatively low heat resistance is used.
In the case of photopolymerization, a patterned polarizer may be obtained by masking, developing, or the like.
Examples of the light source of the active energy ray include a low-pressure mercury lamp, a medium-pressure mercury lamp, a high-pressure mercury lamp, an ultrahigh-pressure mercury lamp, a xenon lamp, a halogen lamp, a carbon arc lamp, a tungsten lamp, a gallium lamp, an excimer laser, an LED light source that emits light in a wavelength range of 380 to 440nm, a chemical lamp, a black light lamp, a microwave-excited mercury lamp, and a metal halide lamp.
The ultraviolet irradiation intensity is usually 10 to 3000mW/cm 2 . The ultraviolet irradiation intensity is preferably an intensity in a wavelength region effective for activation of the polymerization initiator. The time for irradiation of light is usually 0.1 seconds to 10 minutes, preferably 1 second to 5 minutes, more preferably 5 seconds to 3 minutes, and still more preferably 10 seconds to 1 minute. When irradiated 1 or more times with such ultraviolet irradiation intensity, the cumulative light amount thereof is 10 to 3000mJ/cm 2 Preferably 50 to 2000mJ/cm 2 More preferably 100 to 1000mJ/cm 2
By performing photopolymerization, the polymerizable liquid crystal compound is polymerized in a state of being maintained in a liquid crystal state of a smectic phase, preferably a higher smectic phase, to form a polarizer. The polarizer obtained by polymerizing the polymerizable liquid crystal compound while maintaining the liquid crystal state of the smectic phase is also advantageous in that the polarizing performance is higher than that of a conventional bulk guest polarizing film, that is, a polarizer formed of the liquid crystal state of the nematic phase, due to the effect of the dichroic dye. In addition, there is an advantage that strength is superior to that of a polarizer coated with only a dichroic dye or a lyotropic liquid crystal.
The polarizer of the present invention may be formed using an alignment film. The alignment film is a film having an alignment regulating force for aligning the polymerizable liquid crystal compound in a desired direction. The alignment film preferably has solvent resistance that does not dissolve due to application of a composition containing a polymerizable liquid crystal compound, and heat resistance in a heat treatment for removing a solvent and aligning a polymerizable liquid crystal compound. In the present invention, as the alignment film, a photo-alignment film is preferable from the viewpoints of accuracy and quality of an alignment angle, water resistance and bendability of a polarizing film including the alignment film, and the like. The photo-alignment film is also advantageous in that the direction of the orientation restriction force can be arbitrarily controlled by selecting the polarization direction of the irradiated polarized light.
The photo-alignment film is generally obtained by applying a composition containing a polymer or a monomer having a photoreactive group and a solvent (hereinafter, also referred to as a "composition for forming a photo-alignment film") to a substrate, and irradiating polarized light (preferably polarized UV light).
The photoreactive group is a group that generates liquid crystal aligning ability by irradiation with light. Specifically, examples thereof include a group involved in a photoreaction that causes an alignment ability of a liquid crystal, such as an alignment induction or an isomerization reaction, a dimerization reaction, a photocrosslinking reaction, or a photodecomposition reaction of a molecule generated by light irradiation. Among them, a group participating in dimerization reaction or photocrosslinking reaction is preferable in view of excellent orientation. As the photoreactive group, a group having an unsaturated bond, particularly a double bond, is preferable, and at least 1 group selected from the group consisting of a carbon-carbon double bond (c=c bond), a carbon-nitrogen double bond (c=n bond), a nitrogen-nitrogen double bond (n=n bond), and a carbon-oxygen double bond (c=o bond) is particularly preferable.
Examples of the photoreactive group having a c=c bond include a vinyl group, a polyalkenyl group, a stilbene azole group, a stilbene azolium group, a chalcone group, and a cinnamoyl group. Examples of the photoreactive group having a c=n bond include a group having a structure such as an aromatic Schiff base or an aromatic hydrazone.
Examples of the photoreactive group having n=n bond include an azobenzene group, an azonaphthalene group, an aromatic heterocyclic azo group, a disazo group, and a methyl groupA group, a group having an azobenzene oxide structure, and the like. Examples of the photoreactive group having a c=o bond include a benzophenone group, a coumarin group, an anthraquinone group, and a maleimide group. These groups may have substituents such as alkyl, alkoxy, aryl, allyloxy, cyano, alkoxycarbonyl, hydroxyl, sulfonic acid, haloalkyl, and the like.
Among them, the photoreactive group involved in the photodimerization reaction is preferable, and the cinnamoyl group and the chalcone group are preferable in terms of the light irradiation amount of the polarized light required for the photoalignment is small, and the photoalignment film excellent in thermal stability and temporal stability is easily obtained. As the polymer having a photoreactive group, a polymer having a cinnamoyl group as a cinnamic acid structure at the terminal of a side chain of the polymer is particularly preferable.
The composition for forming a photo-alignment film is applied to a substrate, whereby a photo-alignment inducing layer can be formed on the substrate. The solvent contained in the composition may be the same as the solvent exemplified above as the solvent that can be used in forming the polarizer, and may be appropriately selected according to the solubility of the polymer or monomer having a photoreactive group.
The content of the polymer or monomer having a photoreactive group in the composition for forming a photoalignment film may be appropriately adjusted according to the kind of the polymer or monomer and the thickness of the target photoalignment film, and is preferably at least 0.2 mass%, more preferably in the range of 0.3 to 10 mass% relative to the mass of the composition for forming a photoalignment film. The composition for forming a photo-alignment film may contain a polymer material such as polyvinyl alcohol or polyimide and a photosensitizing agent in a range that does not significantly impair the properties of the photo-alignment film.
As a method of applying the composition for forming a photo-alignment film to a substrate and a method of removing a solvent from the applied composition for forming a photo-alignment film, the same method as the method of applying the composition for forming a polarizer to a substrate and the method of removing a solvent can be mentioned.
The irradiation with polarized light may be performed by directly irradiating polarized UV light to a product obtained by removing a solvent from a composition for forming a photo-alignment film applied to a substrate, or by irradiating polarized light from a substrate side and transmitting the polarized light. In addition, the polarized light is particularly preferably substantially parallel light. The wavelength of the irradiated polarized light may be a wavelength in a wavelength region where the photoreactive group of the polymer or monomer having the photoreactive group can absorb light energy. Specifically, UV (ultraviolet) in the wavelength range of 250 to 400nm is particularly preferable. Examples of the light source used for the polarized light irradiation include a xenon lamp, a high-pressure mercury lamp, an ultrahigh-pressure mercury lamp, a metal halide lamp, ultraviolet light laser such as KrF and ArF, and the like, and more preferably a high-pressure mercury lamp, an ultrahigh-pressure mercury lamp and a metal halide lamp. Among these, a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, and a metal halide lamp are preferable because of the high emission intensity of ultraviolet rays having a wavelength of 313 nm. Polarized UV light can be irradiated by passing light from the aforementioned light source through an appropriate polarizer. As the polarizer, a polarizing filter, a polarizing prism of gram-thompson, gram-taylor, or the like, a wire grid type polarizer may be used.
In rubbing or polarized light irradiation, a plurality of regions (patterns) having different directions of alignment of the liquid crystal may be formed by masking.
In the 1 st protective layer forming step, the curable composition (1) is applied to the surface of the polarizer (the surface opposite to the substrate) by the same method as the method of applying the composition for forming a polarizer to the substrate.
The 1 st protective layer can be obtained by drying and removing the solvent contained in the curable composition (1) and curing the curable composition (1). The drying and removal of the solvent may be performed by natural drying, ventilation drying, heating drying, reduced pressure drying, or the like, but is preferably performed under heating from the viewpoint of productivity. When the solvent is dried and removed under heating, the heating conditions may be appropriately determined according to the type of the water-soluble resin constituting the curable composition (1), the type of the solvent, the amount thereof, and the like. For example, the heating temperature is usually 90 to 140 ℃, preferably 100 to 120 ℃, and the heating time is usually 0.5 to 5 minutes, preferably 1 to 2 minutes.
In the 2 nd protective layer forming step, the curable composition (2) is applied to the surface of the 1 st protective layer (the surface opposite to the polarizer), and the same method as the method of applying the composition for forming a polarizer to a substrate is exemplified.
When the polymerizable compound constituting the curable composition (2) is an active energy ray-curable polymerizable compound, the polymerizable compound contained in the curable composition (2) applied to the 1 st protective layer can be polymerized and cured by irradiation with active energy rays.
The active energy ray and the light source thereof are the same as those exemplified for curing the composition for forming a polarizer. The light irradiation intensity at the time of curing the curable composition (2) varies depending on the composition, and the light irradiation intensity in the wavelength region effective for activation of the polymerization initiator is preferably 0.1 to 1000mW/cm 2 . The light irradiation time at the time of curing of the curable composition (2) is controlled according to each composition, and is not particularly limited, and the cumulative light amount expressed as the product of the light irradiation intensity and the light irradiation time is preferably set to 10 to 5000mJ/cm 2 . When the light irradiation conditions are within the above ranges, the polymerization reaction proceeds sufficiently, and curing can be performed with good productivity.
< polarizing plate >
The present invention includes a polarizing plate (elliptical polarizing plate) having the polarizing film and the phase difference film of the present invention. In the polarizing plate of the present invention, the retardation film preferably satisfies the following formula (X):
100≤Re(550)≤180 (X)
In the formula, re (550) represents the in-plane phase difference value at a wavelength of 550 nm.
When the retardation film has an in-plane retardation value represented by (X), the retardation film functions as a so-called λ/4 plate. From the viewpoint of optical properties, the above formula (X) is preferably 100 nm.ltoreq.Re (550). Ltoreq.180 nm, more preferably 120 nm.ltoreq.Re (550). Ltoreq.160 nm.
In the polarizing plate of the present invention, the angle between the slow axis of the retardation film and the absorption axis of the polarizing film is preferably substantially 45 °. In the present invention, the term "substantially 45 °" means45±5°.
Further, the retardation film preferably satisfies the following formula (Y):
Re(450)/Re(550)<1 (Y)
in the formula, re (450) and Re (550) represent in-plane phase difference values at wavelengths of 450nm and 550nm, respectively.
The retardation film satisfying the above formula (Y) has so-called reverse wavelength dispersibility and exhibits excellent polarizing performance. The value of Re (450)/Re (550) is preferably 0.93 or less, more preferably 0.88 or less, further preferably 0.86 or less, preferably 0.80 or more, further preferably 0.82 or more.
The retardation film may be a stretched film obtained by stretching a polymer to impart a retardation, and is preferably composed of a polymerizable liquid crystal composition (hereinafter, also referred to as "polymerizable liquid crystal composition (B)") containing a polymer of a polymerizable liquid crystal compound from the viewpoint of reducing the thickness of a polarizing plate. In the retardation film, the polymerizable liquid crystal compound is usually polymerized in an aligned state. The polymerizable liquid crystal compound (hereinafter, also referred to as "polymerizable liquid crystal compound (B)") forming the retardation film means a liquid crystal compound having a polymerizable functional group, particularly a photopolymerizable functional group.
The photopolymerizable functional group means a group that can participate in polymerization reaction by a living radical, an acid, or the like generated by a photopolymerization initiator. Examples of the photopolymerizable functional group include vinyl, vinyloxy, 1-chlorovinyl, isopropenyl, 4-vinylphenyl, acryloyloxy, methacryloyloxy, oxetanyl, and oxetanyl. Among them, acryloyloxy, methacryloyloxy, vinyloxy, oxetanyl and oxetanyl groups are preferable, and acryloyloxy is more preferable. The liquid crystal may be a thermotropic liquid crystal, a lyotropic liquid crystal, a nematic liquid crystal, or a smectic liquid crystal as a phase ordered structure. As the polymerizable liquid crystal compound, only 1 kind may be used, or 2 or more kinds may be used in combination.
The polymerizable liquid crystal compound (B) is preferably a compound having the following characteristics (I) to (IV) from the viewpoints of ease of film formation and imparting retardation represented by the above formula (Y).
(I) Is a compound having thermotropic liquid crystallinity;
(II) has pi electrons in the long axis direction (a) of the polymerizable liquid crystal compound.
(III) has pi electrons in a direction intersecting with the long axis direction (a) [ intersecting direction (b) ].
(IV) the sum of pi electrons present in the long axis direction (a) is N (pi a), the sum of molecular weights present in the long axis direction is N (Aa), and the pi electron density in the long axis direction (a) of the polymerizable liquid crystal compound is defined by the following formula (i):
D(πa)=N(πa)/N(Aa) (i)
the total of pi electrons present in the cross direction (b) is denoted as N (pi b), the total of molecular weights present in the cross direction (b) is denoted as N (Ab), and the pi electron density in the cross direction (b) of the polymerizable liquid crystal compound is defined by the following formula (ii):
D(πb)=N(πb)/N(Ab) (ii)
the relationship between D (pi a) and D (pi b) is 0-1 [ D (pi a)/D (pi b) ].
The polymerizable liquid crystal compounds (B) satisfying the above (I) to (IV) can form a nematic phase by, for example, applying the compound (B) onto an alignment film formed by rubbing treatment and heating the film to a temperature equal to or higher than the phase transition temperature. The nematic phase formed by aligning the polymerizable liquid crystal compound (B) is generally aligned such that the long axis directions of the polymerizable liquid crystal compounds are parallel to each other, and the long axis directions are alignment directions of the nematic phase.
The polymerizable liquid crystal compound (B) having the above-mentioned characteristics generally exhibits inverse wavelength dispersibility in many cases. Examples of the compound satisfying the characteristics (I) to (IV) include compounds represented by the following formula (II).
The compound represented by the above formula (II) may be used singly or in combination of two or more.
In the formula (II), ar represents a divalent aromatic group which may have a substituent. The aromatic group herein means a group having a planar cyclic structure and having pi electrons of [4n+2] numbers in accordance with the Skoter rule. Here, n represents an integer. When a ring structure is formed by including heteroatoms such as-n=, -S-, etc., the case where the aromatic nature is satisfied by including a pair of non-covalent electrons on these heteroatoms is also included. The divalent aromatic group preferably contains at least 1 or more of nitrogen atom, oxygen atom and sulfur atom.
In the formula (II), G 1 G (G) 2 Each independently represents a divalent aromatic group or a divalent alicyclic hydrocarbon group. The hydrogen atom contained in the divalent aromatic group or the divalent alicyclic hydrocarbon group may be substituted with a halogen atom, an alkyl group having 1 to 4 carbon atoms, a fluoroalkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a cyano group or a nitro group, and the carbon atoms constituting the divalent aromatic group or the divalent alicyclic hydrocarbon group may be substituted with an oxygen atom, a sulfur atom or a nitrogen atom.
In the formula (II), L 1 、L 2 、B 1 B (B) 2 Each independently is a single bond or a divalent linking group.
In the formula (II), k and l each independently represent an integer of 0 to 3, and satisfy the relation of 1.ltoreq.k+l. Here, in the case where 2.ltoreq.k+l, B 1 B (B) 2 、G 1 G (G) 2 And may be the same or different from each other.
In the formula (II), E 1 E and E 2 Each independently represents an alkanediyl group having 1 to 17 carbon atoms, wherein hydrogen atoms contained in the alkanediyl group may be substituted with halogen atoms, and wherein-CH is contained in the alkanediyl group 2 Can be substituted by-O-, -S-, -Si-substitution. P (P) 1 P 2 Independently of one another, a polymerizable group or a hydrogen atom, at least 1 of which is a polymerizable group.
In the formula (II), G 1 G (G) 2 Each independently is preferably 1, 4-phenylene (phenyleneidyl) which may be substituted with at least 1 substituent selected from the group consisting of a halogen atom and an alkyl group having 1 to 4 carbon atoms, 1, 4-cyclohexanediyl which may be substituted with at least 1 substituent selected from the group consisting of a halogen atom and an alkyl group having 1 to 4 carbon atoms, more preferably 1, 4-phenylene substituted with a methyl groupThe group, unsubstituted 1, 4-phenylene group, or unsubstituted 1, 4-trans-cyclohexanediyl group is particularly preferably unsubstituted 1, 4-phenylene group, or unsubstituted 1, 4-trans-cyclohexanediyl group. In addition, a plurality of G's are preferably present 1 G (G) 2 At least 1 of them is a divalent alicyclic hydrocarbon group, and further, more preferably with L 1 Or L 2 Bonded G 1 G (G) 2 At least 1 of them is a divalent alicyclic hydrocarbon group.
In the formula (II), L 1 L and L 2 Each independently is preferably a single bond, an alkylene group having 1 to 4 carbon atoms, -O-, -S-, -R a1 OR a2 -、-R a3 COOR a4 -、-R a5 OCOR a6 -、-R a7 OC=OOR a8 -、-N=N-、-CR c =CR d -, or-C.ident.C-. Here, R is a1 ~R a8 Each independently represents a single bond or an alkylene group having 1 to 4 carbon atoms, R c R is R d Represents an alkyl group having 1 to 4 carbon atoms or a hydrogen atom. L (L) 1 L and L 2 More preferably each independently is a single bond, -OR a2-1 -、-CH 2 -、-CH 2 CH 2 -、-COOR a4-1 -, or-OCOR a6-1 -. Here, R is a2-1 、R a4-1 、R a6-1 Each independently represents a single bond, -CH 2 -、-CH 2 CH 2 -any one of the following. L (L) 1 L and L 2 Each independently further preferably is a single bond, -O-, -CH 2 CH 2 -、-COO-、-COOCH 2 CH 2 -, or-OCO-.
In a preferred embodiment of the present invention, G in formula (II) may be used 1 G (G) 2 At least 1 of them is a divalent alicyclic hydrocarbon group through a divalent aromatic group Ar which may have a substituent and L as-COO- 1 And/or L 2 A polymerizable liquid crystal compound obtained by bonding.
In the formula (II), B 1 B (B) 2 Each independently is preferably a single bond, an alkylene group having 1 to 4 carbon atoms, -O-, -S-, -R a9 OR a10 -、-R a11 COOR a12 -、-R a13 OCOR a14 -, or-R a15 OC=OOR a16 -. Here, R is a9 ~R a16 Each independently represents a single bond or an alkylene group having 1 to 4 carbon atoms.
B 1 B (B) 2 More preferably each independently is a single bond, -OR a10-1 -、-CH 2 -、-CH 2 CH 2 -、-COOR a12-1 -, or-OCOR a14-1 -. Here, R is a10-1 、R a12-1 、R a14-1 Each independently represents a single bond, -CH 2 -、-CH 2 CH 2 -any one of the following. B (B) 1 B (B) 2 Each independently further preferably is a single bond, -O-, -CH 2 CH 2 -、-COO-、-COOCH 2 CH 2 -, -OCO-, or-OCOCH 2 CH 2 -。
In the formula (II), from the viewpoint of exhibiting inverse wavelength dispersibility, k and l are preferably in the range of 2.ltoreq.k+l.ltoreq.6, preferably k+l=4, more preferably k=2 and l=2. k=2 and l=2, a symmetrical structure is further preferable.
In the formula (II), E 1 E and E 2 Each independently is preferably an alkanediyl group having 1 to 17 carbon atoms, and more preferably an alkanediyl group having 4 to 12 carbon atoms.
In the formula (II), P is 1 Or P 2 Examples of the polymerizable group include an epoxy group, a vinyl group, a vinyloxy group, a 1-chlorovinyl group, an isopropenyl group, a 4-vinylphenyl group, an acryloyloxy group, a methacryloyloxy group, an oxetanyl group, and an oxetanyl group. Among these, acryloyloxy, methacryloyloxy, vinyloxy, oxetanyl and oxetanyl groups are preferable, and acryloyloxy is more preferable.
In the formula (II), ar preferably has at least 1 selected from an aromatic hydrocarbon ring which may have a substituent, an aromatic heterocyclic ring which may have a substituent, and an electron withdrawing group. Examples of the aromatic hydrocarbon ring include benzene ring, naphthalene ring, and anthracene ring, and benzene ring and naphthalene ring are preferable. Examples of the aromatic heterocycle include a furan ring, a benzofuran ring, a pyrrole ring, an indole ring, a thiophene ring, a benzothiophene ring, a pyridine ring, a pyrazine ring, a pyrimidine ring, a triazole ring, a triazine ring, a pyrroline ring, an imidazole ring, a pyrazole ring, a thiazole ring, a benzothiazole ring, a thienothiazole ring, an oxazole ring, a benzoxazole ring, and a phenanthroline ring. Of these, a thiazole ring, a benzothiazole ring, or a benzofuran ring is preferable, and a benzothiazolyl group is more preferable. When a nitrogen atom is contained in Ar, the nitrogen atom preferably has pi electrons.
In the formula (II), ar represents a total number N of pi electrons contained in the divalent aromatic group π Preferably 8 or more, more preferably 10 or more, further preferably 14 or more, and particularly preferably 16 or more. The content is preferably 30 or less, more preferably 26 or less, and even more preferably 24 or less.
Examples of the aromatic group represented by Ar include groups represented by the formulae (Ar-1) to (Ar-23).
In the formulae (Ar-1) to (Ar-23), the symbol represents a linking part, Z 0 、Z 1 Z is as follows 2 Each independently represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 12 carbon atoms, a cyano group, a nitro group, an alkylsulfinyl group having 1 to 12 carbon atoms, an alkylsulfonyl group having 1 to 12 carbon atoms, a carboxyl group, a fluoroalkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an alkylthio group having 1 to 12 carbon atoms, an N-alkylamino group having 1 to 12 carbon atoms, an N, N-dialkylamino group having 2 to 12 carbon atoms, an N-alkylsulfonyl group having 1 to 12 carbon atoms, or an N, N-dialkylsulfamoyl group having 2 to 12 carbon atoms.
In the formulae (Ar-1) to (Ar-23), Q 1 Q and Q 2 Each independently represents-CR 2’ R 3’ -、-S-、-NH-、-NR 2’ -, -CO-or O-, R 2’ R is R 3’ Each independently represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms.
In the formulae (Ar-1) to (Ar-23), J 1 J 2 Each independently represents a carbon atom, or a nitrogen atom.
In the formulae (Ar-1) to (Ar-23), Y 1 、Y 2 Y and Y 3 Each independently represents an aromatic hydrocarbon group or an aromatic heterocyclic group which may be substituted.
In the formulae (Ar-1) to (Ar-23), W 1 W and W 2 Each independently represents a hydrogen atom, a cyano group, a methyl group or a halogen atom, and m represents an integer of 0 to 6.
As Y 1 、Y 2 Y and Y 3 Examples of the aromatic hydrocarbon group in (a) include aromatic hydrocarbon groups having 6 to 20 carbon atoms such as phenyl, naphthyl, anthryl, phenanthryl and biphenyl, and preferably phenyl and naphthyl, more preferably phenyl. Examples of the aromatic heterocyclic group include an aromatic heterocyclic group having 4 to 20 carbon atoms and containing at least one hetero atom such as a nitrogen atom, an oxygen atom, a sulfur atom, etc., such as a furyl group, a pyrrolyl group, a thienyl group, a pyridyl group, a thiazolyl group, a benzothiazolyl group, etc., and a furyl group, a thienyl group, a pyridyl group, a thiazolyl group, a benzothiazolyl group are preferable.
Y 1 Y and Y 2 Each independently may be a polycyclic aromatic hydrocarbon group or a polycyclic aromatic heterocyclic group which may be substituted. Polycyclic aromatic hydrocarbon groups refer to condensed polycyclic aromatic hydrocarbon groups or groups derived from an aromatic ring set. Polycyclic aromatic heterocyclic groups refer to fused polycyclic aromatic heterocyclic groups, or groups derived from an aromatic ring set.
In the formulae (Ar-1) to (Ar-23), Z 0 、Z 1 Z is as follows 2 Each independently is preferably a hydrogen atom, a halogen atom, an alkyl group having 1 to 12 carbon atoms, a cyano group, a nitro group, an alkoxy group having 1 to 12 carbon atoms, Z 0 More preferably a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, a cyano group, and Z 1 Z is as follows 2 Further preferred are a hydrogen atom, a fluorine atom, a chlorine atom, a methyl group and a cyano group.
In the formulae (Ar-1) to (Ar-23), Q 1 Q and Q 2 preferably-NH-, -S-, -NR 2’ -、-O-,R 2’ Preferably a hydrogen atom. Of these, particularly preferred are-S-; -O-, -NH-.
Among the formulae (Ar-1) to (Ar-23), the formulae (Ar-6) and (Ar-7) are preferable from the viewpoint of stability of the molecule.
In the formulae (Ar-17) to (Ar-23), Y 1 To which nitrogen atoms, Z, may be bound 0 Together forming an aromatic heterocyclic group. Examples of the aromatic heterocyclic group include aromatic heterocyclic groups which may be contained in Ar and are described above, and examples thereof include pyrrole rings, imidazole rings, pyrroline rings, pyridine rings, pyrazine rings, pyrimidine rings, indole rings, quinoline rings, isoquinoline rings, purine rings, pyrrolidine rings, and the like. The aromatic heterocyclic group may have a substituent. In addition, Y 1 To which nitrogen atoms, Z, may be bound 0 Together form the above-mentioned optionally substituted polycyclic aromatic hydrocarbon group or polycyclic aromatic heterocyclic group. For example, a benzofuran ring, a benzothiazole ring, and a benzoxazole ring can be cited. The compound represented by the formula (II) can be produced, for example, by the method described in JP-A2010-31223.
The content of the polymerizable liquid crystal compound (B) in the polymerizable liquid crystal composition (B) constituting the retardation film is, for example, 70 to 99.5 parts by mass, preferably 80 to 99 parts by mass, and more preferably 90 to 98 parts by mass, relative to 100 parts by mass of the solid content of the polymerizable liquid crystal composition (B). When the content is within the above range, the orientation of the retardation film tends to be high. The solid content herein refers to the total amount of components remaining after volatile components such as solvents are removed from the polymerizable liquid crystal composition (B).
The polymerizable liquid crystal composition (B) may contain a polymerization initiator for initiating the polymerization reaction of the polymerizable liquid crystal compound (B). The polymerization initiator may be appropriately selected from among polymerization initiators conventionally used in this field, may be a thermal polymerization initiator or a photopolymerization initiator, and is preferably a photopolymerization initiator in view of initiation of polymerization under relatively low temperature conditions. The same photopolymerization initiator as exemplified above as the photopolymerization initiator usable in the polymerizable liquid crystal composition (a) is preferably exemplified. The polymerizable liquid crystal composition (B) may contain a photosensitizing agent, a leveling agent, and additives exemplified as additives contained in the polymerizable liquid crystal composition (a), if necessary. Examples of the photosensitizing agent and the leveling agent include the same ones as those exemplified above as the photosensitizing agent and the leveling agent which can be used in the polymerizable liquid crystal composition (a).
The retardation film can be obtained, for example, by the following method: a composition prepared by adding a solvent to a polymerizable liquid crystal composition (B) containing a polymerizable liquid crystal compound (B) and, if necessary, a polymerization initiator, an additive, and the like (hereinafter, also referred to as a "composition for forming a retardation film") is applied to a substrate or an alignment film, the solvent is removed by drying, and the polymerizable liquid crystal compound (B) in the obtained coating film is cured by heating and/or an active energy ray. Examples of the substrate and/or orientation film that can be used for producing the retardation film include the same substrate and/or orientation film as those exemplified above as the substrate and/or orientation film that can be used for producing the polarizer of the present invention.
The solvent used in the composition for forming a retardation film, the method of applying the composition for forming a retardation film, the curing conditions by active energy rays, and the like are the same as those employable in the method for producing a polarizer of the present invention.
The thickness of the retardation film may be appropriately selected depending on the display device to be used, and is preferably 0.1 to 10 μm, more preferably 1 to 5 μm, and even more preferably 1 to 3 μm from the viewpoints of thickness reduction, bendability, and the like.
The polarizing plate of the present invention may further include other layers (adhesive layers, etc.) in addition to the polarizing film and the retardation film of the present invention. In the polarizing plate of the present invention, for example, the 2 nd protective layer of the polarizing film of the present invention and the retardation film may be bonded via an adhesive layer.
The thickness of the polarizing plate of the present invention is preferably 10 to 300 μm, more preferably 20 to 200 μm, and even more preferably 25 to 100 μm, from the viewpoints of flexibility and visibility of the display device.
< display device >
The present invention includes a display device including the polarizing film of the present invention or the polarizing plate of the present invention. The display device of the present invention can be obtained by bonding the polarizing film or polarizing plate of the present invention to the surface of the display device via an adhesive layer, for example. The display device is a device having a display mechanism, and includes a light emitting element or a light emitting device as a light emitting source. Examples of the display device include a liquid crystal display device, an organic Electroluminescence (EL) display device, an inorganic Electroluminescence (EL) display device, a touch panel display device, an electron emission display device (a field emission display device (FED or the like), a surface conduction field emission display device (SED)), electronic paper (a display device using electronic ink or an electrophoretic element), a plasma display device, a projection display device (a Grating Light Valve (GLV) display device, a display device having a Digital Micromirror Device (DMD), and a piezoelectric ceramic display. The liquid crystal display device includes all of a transmissive liquid crystal display device, a semi-transmissive liquid crystal display device, a reflective liquid crystal display device, a direct-view liquid crystal display device, a projection liquid crystal display device, and the like. These display devices may be display devices that display two-dimensional images, or may be stereoscopic display devices that display three-dimensional images. In particular, the display device of the present invention is preferably an organic EL display device or a touch panel display device, and particularly preferably an organic EL display device.
Examples
The present invention will be described in more detail with reference to examples and comparative examples, but the present invention is not limited to these examples. Hereinafter, unless otherwise indicated, the amounts, parts and% of the amounts are based on mass.
< preparation of composition for Forming polarizer >
The following ingredients were mixed and stirred at 80℃for 1 hour, thereby obtaining a composition for forming a polarizer. As the dichroic dye, an azo dye described in examples of Japanese patent application laid-open No. 2013-101328 is used.
[ polymerizable liquid Crystal Compound ]
[ dichroism pigment ]
Azo pigments;
[ polymerization initiator ]
6 parts by weight of 2-dimethylamino-2-benzyl-1- (4-morpholinophenyl) butan-1-one (Irgacure 369; ciba Specialty Chemicals Co., ltd.)
[ leveling agent ]
1.2 parts of polyacrylate compound (BYK-361N; BYK-Chemie Co., ltd.)
[ solvent ]
O-xylene 400 parts
< 1 preparation of curable composition (1) for Forming protective layer >
A1 st curable composition (1) for forming a protective layer was prepared by mixing 100 parts by mass of pure water, 3.0 parts by mass of "Kuraray POVAL KL318" (trade name: carboxyl group-modified polyvinyl alcohol) manufactured by Kuraray, and 1.5 parts by mass of a water-soluble polyamide epoxy Resin (Sumika Chemtex 650 "(trade name) manufactured by Sumirez Resin, a use solution having a solid content of 30%). The "sumitez Resin 650" represents the mass of the solid content.
< preparation of curable composition (2) for Forming protective layer >
The curable compositions (2) for forming the 2 nd protective layer of production examples 1 to 7 were prepared by mixing the respective components according to the compositions shown in Table 1.
TABLE 1
The components constituting the curable composition (2) described in table 1 are shown below.
[ alicyclic epoxy Compound (B2) ]
Celloxide 2021P:3, 4-epoxycyclohexylmethyl 3, 4-epoxycyclohexane carboxylate (manufactured by Daicel chemical Co., ltd.)
EHPE3150: 1, 2-epoxy-4- (2-oxiranyl) cyclohexane adduct of 2, 2-bis (hydroxymethyl) -1-butanol (manufactured by Daicel chemical Co., ltd.)
[ aliphatic epoxy Compound (B1) ]
EX-214:1, 4-butanediol diglycidyl ether (Nagase ChemteX Co., ltd.)
[ aromatic epoxy Compound (B3) ]
TECHMORE VG3101L:2- [4- (2, 3-epoxypropoxy) phenyl ] -2- [4- [1, 1-bis [4- ([ 2, 3-epoxypropoxy ] phenyl ] ethyl ] phenyl ] propane (manufactured by Printec)
[ oxetane compound (A) (binary) ]
OXT-221: bis (3-ethyl-3-oxetanylmethyl) ether (manufactured by Toyama Synthesis Co., ltd.)
[ oxetane compound (unitary) ]
OXT-212: 2-ethylhexyl oxetane (manufactured by Toyama Synthesis Co., ltd.)
[ polymerization initiator ]
CPI-100P: photo cation polymerization initiator: propylene carbonate 50 solution of hexafluorophosphate triarylsulfonium salt (San-Apro Co., ltd.)
[ leveling agent ]
SH710: organosilicon leveling agent (Dow Corning Toray (manufactured by Kagaku Kogyo Co., ltd.))
1. Example 1
(1) Preparation of photo-alignment film on substrate
(i) Preparation of composition for Forming photo-alignment film
The following photo-alignment polymer was mixed with the following solvent in the following ratio, and the resulting mixture was stirred at 80℃for 1 hour, thereby obtaining a composition for forming a photo-alignment film. The following photo-alignment polymer was prepared by the method described in Synthesis example 1 of Japanese patent application laid-open No. 2013-033249, and had a number average molecular weight of 28200 and Mw/Mn of 1.82.
[ photo-oriented Polymer ]
[ solvent ]
O-xylene 98 parts
(ii) Production of base film with photo-alignment film
As a substrate, a triacetyl cellulose film (KC 4UY, manufactured by KONICA MINOLTA) was used, and after corona treatment was applied to the film surface, the composition for forming a photo-alignment film was applied, and dried at 120 ℃. The dried film was irradiated with polarized UV light to form a photo-alignment film, thereby obtaining a film with a photo-alignment film. The polarized UV light treatment was carried out using a UV irradiation apparatus (SPOTCURE SP-7; manufactured by Ushio Motor Co., ltd.) under the condition that the intensity measured at a wavelength of 365nm was 100 mJ.
(2) Manufacture of polarizer
The above-mentioned composition for forming a polarizer was coated on the substrate film with a photoalignment film obtained in the above-mentioned manner by a bar coating method (# 9, 30 mm/s), and the resultant was heated and dried for 1 minute by a drying oven at 120℃to thereby phase-change the polymerizable liquid crystal compound into a liquid phase, and then cooled to room temperature to phase-change the polymerizable liquid crystal compound into a smectic liquid crystal state. Next, an exposure amount was set to 1000mJ/cm using a UV irradiation apparatus (SPOTCURE SP-7; manufactured by Ushio Motor Co., ltd.) 2 By irradiating ultraviolet rays (based on 365 nm) to a layer formed from the composition for forming a polarizing film, the polymerizable liquid crystal compound contained in the dried film is polymerized while maintaining the smectic liquid crystal state of the polymerizable liquid crystal compound, and a polarizing film is formed from the dried film. The film thickness of the polarizing film was measured by a laser microscope (OLS 3000, olympus Co., ltd.) and found to be 2.3. Mu.m. The bag thus obtainedA polarizer film comprising a polarizer and a substrate film. The polarizer film was subjected to X-ray diffraction measurement by irradiating X-ray from the absorption axis direction of the polarizer film using an X' Pert PRO MPD (manufactured by spectra corporation), and as a result, a sharp diffraction peak (bragg peak) having a half-width (FWHM) =about 0.17 ° was obtained in the vicinity of 2θ=20.2 °. The ordered period (d) determined from the peak position is about It was confirmed that a structure reflecting a higher order smectic phase was formed.
(3) Production of the 1 st protective layer
After the polarizer surface of the polarizer film obtained in the above manner was subjected to corona treatment, the composition of production example 8, which was the 1 st curable composition for forming a protective layer (1), was applied using a bar coater so that the film thickness after curing became about 0.5 μm. Then, the film was dried at 100℃for 1.5 minutes to obtain a polarizer film having the 1 st protective layer.
(4) Production of the 2 nd protective layer
Further, the 1 st protective layer surface of the polarizer film with the 1 st protective layer obtained in the above-described manner was subjected to corona treatment, and then the composition of production example 3 as the 2 nd protective layer-forming curable composition (2) was applied using a bar coater so that the film thickness after curing became about 1.5 μm. Next, the exposure amount was set to 500mJ/cm using a UV irradiation apparatus (SPOTCURE SP-7; manufactured by Ushio Motor Co., ltd.) 2 The layer formed of the 2 nd curable composition for forming a protective layer (2) (composition of production example 3) was cured by irradiation with ultraviolet light (365 nm basis), and the polarizing film of example 1 formed of the cured product of the 2 nd curable composition for forming a protective layer (2)/the cured product of the 1 st curable composition for forming a protective layer (1)/the polarizer/the photo-alignment film/the base film was produced.
2. Example 2
A polarizing film of example 2 was produced in the same manner as in example 1, except that the 1 st protective layer had a thickness of 1.0 μm and the 2 nd protective layer had a thickness of 0.7 μm.
3. Example 3
A polarizing film of example 3 was produced in the same manner as in example 1, except that the thickness of the 1 st protective layer was 1.0 μm.
4. Examples 4 and 5
Polarizing films of examples 4 and 5 were produced in the same manner as in example 1, except that the composition of production example 1 or 2 shown in table 1 was used instead of the composition of production example 3 as the curable composition (2) for forming the 2 nd protective layer, and the thickness of the 2 nd protective layer was 0.7 μm.
5. Example 6
A polarizing film of example 6 was produced in the same manner as in example 1, except that the thickness of the 2 nd protective layer was made 0.7 μm.
6. Examples 7 to 10
Polarizing films of examples 7 to 10 were produced in the same manner as in example 1, except that the compositions of production examples 4 to 7 shown in Table 1 were used as the curable composition (2) for forming the 2 nd protective layer instead of the composition of production example 3, and the thickness of the 2 nd protective layer was set to 0.7. Mu.m.
7. Comparative example 1
A polarizer film with the 1 st protective layer was produced in the same manner as in example 1, and the polarizer laminate of comparative example 1 was produced without providing the 2 nd protective layer.
8. Comparative example 2
The polarizer surface of the polarizer film obtained in the same manner as in example 1 was subjected to corona treatment, and then the curable composition of production example 3 was applied using a bar coater so that the film thickness after curing became about 0.7 μm. Next, the exposure amount was set to 500mJ/cm using a UV irradiation apparatus (SPOTCURE SP-7; manufactured by Ushio Motor Co., ltd.) 2 The layer formed of the curable composition of production example 3 was irradiated with ultraviolet light (365 nm, reference), and the curable composition was cured to produce a polarizer film having a cured layer of the curable composition of production example 3.
Next, corona treatment was performed on the surface of the cured product layer of the polarizer film having the cured product layer of the curable composition of production example 3, and then the curable composition of production example 8 was applied using a bar coater so that the film thickness after curing became about 0.5 μm. Next, the laminate was dried at 100 ℃ for 1.5 minutes to prepare a polarizer laminate of comparative example 2 formed of the cured product layer of the curable composition of production example 8/the cured product layer of the curable composition of production example 3/the polarizer/the photo-alignment film/the base film.
9. Comparative example 3
The polarizer surface of the polarizer film obtained in the same manner as in example 1 was subjected to corona treatment, and then the curable composition of production example 3 was applied using a bar coater so that the film thickness after curing became about 0.7 μm. Next, the exposure amount was set to 500mJ/cm using a UV irradiation apparatus (SPOTCURE SP-7; manufactured by Ushio Motor Co., ltd.) 2 The curable composition of production example 3 was cured by irradiating the layer formed of the curable composition with ultraviolet light (based on 365 nm), and a polarizer laminate of comparative example 3 formed of the cured layer of the curable composition of production example 3, a polarizer, a photo-alignment film, and a base material film was produced.
< measurement of polarization degree Py and monomer transmittance Ty >
The polarization degree Py and the monomer transmittance Ty of the polarizing films of examples 1 to 10 and the polarizer laminates of comparative examples 1 to 3 were measured in the following manner. Using a device in which a folder with a polarizer was provided in a spectrophotometer (UV-3150 manufactured by shimadzu corporation), the transmittance (Ta) in the transmission axis direction and the transmittance (Tb) in the absorption axis direction were measured in the wavelength range of 380nm to 780nm by a two-beam method. In this folder, the reference side is provided with a net intercepting 50% of the light quantity.
Using the formulas (formula 1) and (formula 2), the individual transmittance and polarization degree at each wavelength were calculated, and further, the visibility correction was performed in accordance with the 2-degree field of view (C light source) of JIS Z8701, and the visibility correction individual transmittance (Ty) and the visibility correction polarization degree (Py) were calculated.
Monomer transmittance Ty (%) = (ta+tb)/2 (formula 1)
Polarization degree Py (%) = (Ta-Tb)/(ta+tb) ×100 (formula 2)
The polarizing films of examples 1 to 10 and the polarizer laminates of comparative examples 1 to 3 were evaluated for heat resistance and moist heat resistance according to the following methods. The results are shown in Table 2.
< evaluation of Heat resistance >
After the polarizing film and the polarizer laminate were heated at 85 ℃ for 240 hours, the degree of polarization Py and the monomer transmittance Ty of the polarizing film and the polarizer laminate were measured again, and the change rate amounts (Δpy and Δty) before and after the heat resistance test were calculated.
< evaluation of moist Heat resistance >
After heating the polarizing film and the polarizer laminate at 60 ℃ for 240 hours at 90% rh, the degree of polarization Py and the monomer transmittance Ty of the polarizing film and the polarizer laminate were measured again, and the change rate amounts (Δpy and Δty) before and after the heat and humidity resistance test were calculated.
The polarizing films of examples 1 to 10 and the polarizer laminates of comparative examples 1 to 3 were evaluated for acid resistance by the following methods. The results are shown in Table 2.
< evaluation of acid resistance >
An 18 mass% aqueous hydrochloric acid solution was added dropwise to the surface of the protective layer (cured product layer) that is the outermost layer of the polarizing film and the polarizer laminate, and after standing for 2 minutes, the change in shape and color phase was evaluated visually. The laminate after standing was visually observed with a white background under LED illumination, and the occurrence of irregularities due to swelling of the protective layer (cured layer) was judged as "x", and the occurrence of no change in shape was judged as "o". In addition, regarding the hue, a case where a change from achromatic color to magenta or red was observed was determined as "x", and a case where no change in the color phase was observed was determined as "o".
TABLE 2
The polarizing film of the present invention was confirmed to have excellent heat resistance, humidity resistance and acid resistance.

Claims (11)

1. A polarizing film comprising, in order, a polarizer, a 1 st protective layer, and a 2 nd protective layer, the polarizer being a cured product of a polymerizable liquid crystal composition comprising a polymerizable liquid crystal compound having at least one polymerizable group and a dichroic dye,
the 1 st protective layer is a cured product layer of a curable composition containing a polyvinyl alcohol resin,
the 2 nd protective layer is a cured product layer of a curable composition containing a polymerizable compound,
the curable composition in the 2 nd protective layer contains a polymerizable compound having a cyclic ether structure as the polymerizable compound,
the 1 st protective layer is arranged on one surface of the polaroid,
the 2 nd protective layer is arranged on the 1 st protective layer.
2. The polarizing film according to claim 1, wherein the curable composition in the 2 nd protective layer comprises a cationically polymerizable compound as the polymerizable compound.
3. The polarizing film according to claim 1 or 2, wherein the curable composition in the 2 nd protective layer comprises an oxetane compound having an oxetanyl group as the polymerizable compound.
4. The polarizing film according to any one of claims 1 to 3, wherein the curable composition in the 2 nd protective layer comprises an oxetane compound having two or more oxetanes as the polymerizable compound.
5. The polarizing film according to claim 4, wherein the content of the oxetane compound having two or more oxetanes is 30 parts by mass or more based on 100 parts by mass of the total amount of all polymerizable compounds contained in the curable composition for forming the 2 nd protective layer.
6. The polarizing film according to any one of claims 1 to 5, wherein the dichroic dye is an azo dye.
7. The polarizing film according to any one of claims 1 to 6, wherein the polymerizable liquid crystal compound exhibits a smectic liquid crystal phase.
8. The polarizing film according to any one of claims 1 to 7, wherein the polarizer exhibits a bragg peak in an X-ray analysis measurement.
9. A polarizing plate comprising the polarizing film according to any one of claims 1 to 8 and a phase difference film satisfying formula (X):
100≤Re(550)≤180(X),
where Re (550) represents the in-plane phase difference value at a wavelength of 550nm,
the slow axis of the retardation film and the absorption axis of the polarizing film form an angle of substantially 45 degrees.
10. The polarizing plate according to claim 9, wherein the retardation film satisfies formula (Y):
Re(450)/Re(550)<1(Y),
wherein Re (450) and Re (550) represent in-plane phase difference values at wavelengths of 450nm and 550nm, respectively.
11. A display device comprising the polarizing film according to any one of claims 1 to 8, or the polarizing plate according to any one of claims 9 to 10.
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Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR20230002504A (en) * 2020-04-30 2023-01-05 닛토덴코 가부시키가이샤 Polarizing plate and polarizing plate with optical function layer
JP2021177229A (en) * 2020-04-30 2021-11-11 日東電工株式会社 Polarizing plate and polarizing plate with optical function layer
TW202216454A (en) 2020-07-21 2022-05-01 日商柯尼卡美能達股份有限公司 Polarizing plate, method for producing polarizing plate, and display device
CN114530275B (en) * 2022-04-22 2022-07-08 西安宏星电子浆料科技股份有限公司 Environment-friendly organic gold conductor slurry

Citations (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6236439B1 (en) * 1998-04-20 2001-05-22 Nitto Denko Corporation Wide viewing angle polarizing plate and liquid crystal display
CN101644792A (en) * 2008-08-06 2010-02-10 住友化学株式会社 Polaroid sheet, manufacturing method thereof and liquid crystal display device
JP2010039454A (en) * 2008-08-04 2010-02-18 Maguteiku:Kk Functional intermediate sheet
CN103336325A (en) * 2012-02-28 2013-10-02 住友化学株式会社 Polarizing film, circular polarizing plate and method of producing the same
JP2016085447A (en) * 2014-10-23 2016-05-19 Jxエネルギー株式会社 Retardation plate, elliptically polarizing plate, display device using the same, and polymerizable dichroic dye for retardation plate
CN105745560A (en) * 2013-09-30 2016-07-06 Lg化学株式会社 Polarizing plate, method for manufacturing same, and image display device comprising same
JP2016177248A (en) * 2014-07-16 2016-10-06 日東電工株式会社 Polarization film and manufacturing method thereof
KR20170012321A (en) * 2014-05-30 2017-02-02 스미또모 가가꾸 가부시키가이샤 Polarizing plate provided with adhesive, and liquid crystal display device
CN106646714A (en) * 2015-10-30 2017-05-10 住友化学株式会社 Polarizing plate and display device equipped with the polarizing plate, as well as process for producing the same
CN112189156A (en) * 2018-05-22 2021-01-05 住友化学株式会社 Bendable optical laminate and method for manufacturing same
CN112740084A (en) * 2018-09-28 2021-04-30 住友化学株式会社 Polarizing film and method for producing same

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP4719156B2 (en) 2003-11-06 2011-07-06 住友化学株式会社 Dichroic guest-host polarizer comprising oriented polymer film
JP2010054950A (en) 2008-08-29 2010-03-11 Yukihisa Takeda Functional intermediate sheet and method for manufacturing polarizing lens applying functional intermediate sheet
JP5446902B2 (en) 2009-03-05 2014-03-19 Dic株式会社 Cationic polymerizable adhesive and polarizing plate obtained using the same
JP6171276B2 (en) * 2011-07-12 2017-08-02 住友化学株式会社 Polarizer and manufacturing method thereof
JP6829012B2 (en) 2015-10-07 2021-02-10 住友化学株式会社 Polarizer
KR101933765B1 (en) 2016-08-23 2018-12-28 동우 화인켐 주식회사 Polarizing Plate and Image Display Device Comprising the Same

Patent Citations (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6236439B1 (en) * 1998-04-20 2001-05-22 Nitto Denko Corporation Wide viewing angle polarizing plate and liquid crystal display
JP2010039454A (en) * 2008-08-04 2010-02-18 Maguteiku:Kk Functional intermediate sheet
CN101644792A (en) * 2008-08-06 2010-02-10 住友化学株式会社 Polaroid sheet, manufacturing method thereof and liquid crystal display device
CN103336325A (en) * 2012-02-28 2013-10-02 住友化学株式会社 Polarizing film, circular polarizing plate and method of producing the same
CN105745560A (en) * 2013-09-30 2016-07-06 Lg化学株式会社 Polarizing plate, method for manufacturing same, and image display device comprising same
KR20170012321A (en) * 2014-05-30 2017-02-02 스미또모 가가꾸 가부시키가이샤 Polarizing plate provided with adhesive, and liquid crystal display device
JP2016177248A (en) * 2014-07-16 2016-10-06 日東電工株式会社 Polarization film and manufacturing method thereof
JP2016085447A (en) * 2014-10-23 2016-05-19 Jxエネルギー株式会社 Retardation plate, elliptically polarizing plate, display device using the same, and polymerizable dichroic dye for retardation plate
CN106646714A (en) * 2015-10-30 2017-05-10 住友化学株式会社 Polarizing plate and display device equipped with the polarizing plate, as well as process for producing the same
CN112189156A (en) * 2018-05-22 2021-01-05 住友化学株式会社 Bendable optical laminate and method for manufacturing same
CN112740084A (en) * 2018-09-28 2021-04-30 住友化学株式会社 Polarizing film and method for producing same

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