CN114561172A - Adhesive composition for polarizing film, optical film, and image display device - Google Patents

Adhesive composition for polarizing film, optical film, and image display device Download PDF

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Publication number
CN114561172A
CN114561172A CN202210144686.6A CN202210144686A CN114561172A CN 114561172 A CN114561172 A CN 114561172A CN 202210144686 A CN202210144686 A CN 202210144686A CN 114561172 A CN114561172 A CN 114561172A
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meth
adhesive composition
polarizing film
acrylate
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CN114561172B (en
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大学纪二
齐藤武士
田中香代
木村启介
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Nitto Denko Corp
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Nitto Denko Corp
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    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J135/00—Adhesives based on homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by a carboxyl radical, and containing at least another carboxyl radical in the molecule, or of salts, anhydrides, esters, amides, imides or nitriles thereof; Adhesives based on derivatives of such polymers
    • C09J135/02—Homopolymers or copolymers of esters
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/30—Polarising elements
    • G02B5/3025—Polarisers, i.e. arrangements capable of producing a definite output polarisation state from an unpolarised input state
    • G02B5/3033—Polarisers, i.e. arrangements capable of producing a definite output polarisation state from an unpolarised input state in the form of a thin sheet or foil, e.g. Polaroid
    • G02B5/3041—Polarisers, i.e. arrangements capable of producing a definite output polarisation state from an unpolarised input state in the form of a thin sheet or foil, e.g. Polaroid comprising multiple thin layers, e.g. multilayer stacks
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J11/00—Features of adhesives not provided for in group C09J9/00, e.g. additives
    • C09J11/02—Non-macromolecular additives
    • C09J11/06—Non-macromolecular additives organic
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J11/00—Features of adhesives not provided for in group C09J9/00, e.g. additives
    • C09J11/08—Macromolecular additives
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J133/00—Adhesives based on homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by only one carboxyl radical, or of salts, anhydrides, esters, amides, imides, or nitriles thereof; Adhesives based on derivatives of such polymers
    • C09J133/04—Homopolymers or copolymers of esters
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J4/00—Adhesives based on organic non-macromolecular compounds having at least one polymerisable carbon-to-carbon unsaturated bond ; adhesives, based on monomers of macromolecular compounds of groups C09J183/00 - C09J183/16
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B1/00—Optical elements characterised by the material of which they are made; Optical coatings for optical elements
    • G02B1/10—Optical coatings produced by application to, or surface treatment of, optical elements
    • G02B1/14—Protective coatings, e.g. hard coatings
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/30—Polarising elements
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/30—Polarising elements
    • G02B5/3025—Polarisers, i.e. arrangements capable of producing a definite output polarisation state from an unpolarised input state
    • G02B5/3033—Polarisers, i.e. arrangements capable of producing a definite output polarisation state from an unpolarised input state in the form of a thin sheet or foil, e.g. Polaroid
    • G02B5/3041—Polarisers, i.e. arrangements capable of producing a definite output polarisation state from an unpolarised input state in the form of a thin sheet or foil, e.g. Polaroid comprising multiple thin layers, e.g. multilayer stacks
    • G02B5/305—Polarisers, i.e. arrangements capable of producing a definite output polarisation state from an unpolarised input state in the form of a thin sheet or foil, e.g. Polaroid comprising multiple thin layers, e.g. multilayer stacks including organic materials, e.g. polymeric layers
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333—Constructional arrangements; Manufacturing methods
    • G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333—Constructional arrangements; Manufacturing methods
    • G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
    • G02F1/133528—Polarisers
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B33/00—Electroluminescent light sources
    • H05B33/02—Details
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K50/00—Organic light-emitting devices
    • H10K50/80—Constructional details
    • H10K50/868—Arrangements for polarized light emission
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K59/00—Integrated devices, or assemblies of multiple devices, comprising at least one organic light-emitting element covered by group H10K50/00
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J2203/00—Applications of adhesives in processes or use of adhesives in the form of films or foils
    • C09J2203/318—Applications of adhesives in processes or use of adhesives in the form of films or foils for the production of liquid crystal displays
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J2301/00—Additional features of adhesives in the form of films or foils
    • C09J2301/30—Additional features of adhesives in the form of films or foils characterized by the chemical, physicochemical or physical properties of the adhesive or the carrier
    • C09J2301/312—Additional features of adhesives in the form of films or foils characterized by the chemical, physicochemical or physical properties of the adhesive or the carrier parameters being the characterizing feature

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  • Physics & Mathematics (AREA)
  • Chemical & Material Sciences (AREA)
  • Optics & Photonics (AREA)
  • General Physics & Mathematics (AREA)
  • Organic Chemistry (AREA)
  • Nonlinear Science (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Mathematical Physics (AREA)
  • Adhesives Or Adhesive Processes (AREA)
  • Polarising Elements (AREA)
  • Health & Medical Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Medicinal Chemistry (AREA)
  • Polymers & Plastics (AREA)

Abstract

The adhesive composition for polarizing films, which contains an active energy ray-curable component and a bubble suppressing agent having a reactive group, is used in the present invention, and the bubble suppressing agent is preferably a silicone-based bubble suppressing agent, and the bubble suppressing agent preferably has a (meth) acryloyl group as a reactive group, and the bubble suppressing agent may have a urethane bond or an isocyanurate ring structure.

Description

Adhesive composition for polarizing film, optical film, and image display device
The present application is a divisional application based on patent applications having application dates of 2018, 02/06, 2017, 02/08, application number of 201880005838.6 (international application number PCT/JP2018/004031), and the title of "adhesive composition for polarizing film, optical film, and image display device".
Technical Field
The invention relates to an adhesive composition for a polarizing film, an optical film and an image display device. The polarizing film can be used alone or in combination with an optical film having the polarizing film laminated thereon to form an image display device such as a Liquid Crystal Display (LCD), an organic EL display, a CRT, or a PDP.
Background
The market demand for liquid crystal display devices is rapidly expanding in watches, mobile phones, PDAs, notebook computers, monitors for computers, DVD players, TVs, and the like. A liquid crystal display device is a device for visualizing a polarization state based on switching of liquid crystal, and uses a polarizer according to a display principle thereof. In particular, for TV applications, high brightness, high contrast, and wide viewing angle are increasingly required, and polarizing films are also increasingly required to have high transmittance, high polarization degree, high color reproducibility, and the like.
As the polarizer, an iodine-containing polarizer having a structure in which, for example, polyvinyl alcohol (hereinafter, also simply referred to as "PVA") adsorbs iodine and is stretched is most widely used in general from the viewpoint of having high transmittance and high degree of polarization. As the polarizing film, a polarizing film obtained by laminating transparent protective films on both surfaces of a polarizer by a so-called aqueous adhesive obtained by dissolving a polyvinyl alcohol-based material in water is generally used (patent document 1 below). As the transparent protective film, cellulose triacetate having high moisture permeability or the like is used. In the case where the above aqueous adhesive is used (so-called wet lamination), a drying step is required after the polarizer and the transparent protective film are bonded.
On the other hand, an active energy ray-curable adhesive has been proposed instead of the aqueous adhesive. When the polarizing film is produced using the active energy ray-curable adhesive, the polarizing film can be produced with improved productivity because a drying step is not required. For example, the present inventors have proposed a radical polymerization type active energy ray-curable adhesive using an N-substituted amide monomer as a curable component (patent document 2 below).
Documents of the prior art
Patent document
Patent document 1: japanese patent laid-open No. 2001-296427
Patent document 2: japanese patent laid-open No. 2012 and 052000
Disclosure of Invention
Problems to be solved by the invention
However, from the viewpoint of improvement in the quality of displays, in the market, reduction of fine bubbles which have not been regarded as a problem until now has been demanded for polarizing films. In consideration of many factors of generation of fine bubbles, for example, even when the adhesive composition applied for adhesion does not contain bubbles in the process of adhering films such as a polarizer and a transparent protective film, fine bubbles called "lamination bubbles" may be generated between the polarizer and the transparent protective film by enclosing air when the films are adhered to each other. Therefore, an adhesive composition for a polarizing film capable of forming an adhesive layer capable of suppressing generation of lamination bubbles and improving display quality is demanded in the market.
The present invention has been made in view of the above circumstances, and an object thereof is to provide an adhesive composition for a polarizing film, which is a material of an adhesive layer that improves at least the adhesion between a polarizer and a transparent protective film and reduces lamination bubbles present therebetween.
Means for solving the problems
The present inventors have made intensive studies to solve the above problems, and as a result, have found that the above object can be achieved by blending a bubble suppressing agent having a reactive group into an adhesive composition for a polarizing film, thereby solving the present invention.
That is, the present invention relates to an adhesive composition for a polarizing film, which contains an active energy ray-curable component and a bubble inhibitor having a reactive group.
In the adhesive composition for a polarizing film, the bubble inhibitor is preferably a silicone bubble inhibitor having a reactive group.
In the adhesive composition for a polarizing film, the bubble inhibitor preferably has a (meth) acryloyl group as a reactive group.
In the adhesive composition for a polarizing film, the bubble inhibitor preferably has a urethane bond.
In the adhesive composition for a polarizing film, the bubble inhibitor preferably has an isocyanurate ring structure.
In the adhesive composition for a polarizing film, the content of the bubble inhibitor is preferably 0.01 to 0.6% by weight, based on 100% by weight of the total composition.
In the adhesive composition for a polarizing film, the surface tension before curing is preferably 30mN/m or less.
The adhesive composition for a polarizing film preferably contains at least a radical polymerizable compound as the active energy ray-curable component.
The present invention also relates to a polarizing film having a transparent protective film laminated on at least one surface of a polarizer via an adhesive layer obtained by curing any one of the above adhesive compositions for polarizing films.
In the polarizing film, the thickness of the adhesive layer is preferably 0.2 to 3 μm.
In the polarizing film, it is preferable that the thickness of the adhesive layer is d (μm) and the content of the bubble inhibitor contained in the adhesive layer is y (wt%), so that the following formula (1) is satisfied.
0.1－0.02d≤y≤0.6－0.08d (1)
The present invention also relates to an optical film in which at least 1 sheet of the polarizing film described in any one of the above is laminated, or an image display device using the polarizing film described in any one of the above or the optical film.
ADVANTAGEOUS EFFECTS OF INVENTION
In general, a polarizing film is produced by laminating a polarizer and a transparent protective film via an adhesive layer formed of an adhesive composition for a polarizing film, but when the polarizer and the transparent protective film are bonded, lamination bubbles tend to be generated by enclosing air, and as described above, reduction of the generation of lamination bubbles is demanded in the market. In the present invention, since the bubble inhibitor having a reactive group is added to the adhesive composition for a polarizing film, which is a raw material of the adhesive layer, the surface free energy of the composition before curing can be suppressed to a low level. Thus, the wettability of the adhesive composition for polarizing films with respect to the polarizer and the transparent protective film can be improved, and the adhesive composition for polarizing films can be efficiently spread by wetting even with respect to extremely fine irregularities present on the surfaces of the polarizer and the transparent protective film. As a result, when the polarizer and the transparent protective film are bonded, the generation of lamination bubbles can be reduced.
In the case of applying an adhesive composition to a film substrate, for the purpose of improving the applicability, a technique is known in which a leveling agent such as a fluorine-containing compound having a low surface free energy is added to the adhesive composition. However, when such a leveling agent is generally blended in an adhesive composition, the adhesive composition tends to have reduced adhesion to a film base to be adhered. The reason for this is considered that, when the adhesive composition is cured to form the adhesive layer, the bubble inhibitor remains on the surface of the film base material as an uncured product, and therefore, an interaction that contributes to the adhesive force between the adhesive layer and the film base material is not sufficiently generated.
However, in the present invention, by blending a bubble inhibitor having a reactive group in the adhesive composition, the surface free energy of the composition before curing is effectively suppressed to a low level, and the bubble inhibitor is allowed to enter the adhesive layer by the reactive group of the bubble inhibitor after curing, so that the laminated bubbles can be reduced and the adhesion of the adhesive layer to the polarizer and the transparent protective film to be adhered can be improved. As a result, in the case of using the adhesive composition for a polarizing film of the present invention, as the lamination bubble between the polarizer and the transparent protective film is reduced, the occurrence of appearance defects can be prevented, and further, the adhesiveness between the polarizer and the adhesive layer and the transparent protective film can be improved, thereby improving the adhesive strength between the polarizer and the transparent protective film.
Detailed Description
The adhesive composition for a polarizing film of the present invention contains an active energy ray-curable component and a bubble inhibitor having a reactive group.
< active energy ray-curable component >
The active energy ray-curable component that can be used in the present invention is broadly classified into electron beam-curable components, ultraviolet-curable components, and visible light-curable components. Further, as the curing method, a radical polymerization curing type adhesive composition and a cationic polymerizable adhesive composition can be distinguished. In the present invention, the active energy ray having a wavelength range of 10nm to 380nm is described as ultraviolet ray, and the active energy ray having a wavelength range of 380nm to 800nm is described as visible light. In particular, the active energy ray-curable component (A) usable in the present invention is particularly preferably curable by visible light of 380nm to 450 nm.
< 1: radically polymerizable curable Compound >
Examples of the radical polymerizable compound include compounds having a radical polymerizable functional group having a carbon-carbon double bond such as a (meth) acryloyl group or a vinyl group. Any of monofunctional radical polymerizable compounds and difunctional or higher polyfunctional radical polymerizable compounds can be used as the curable component. These radical polymerizable compounds may be used alone in 1 kind, or in combination with 2 or more kinds. As these radical polymerizable compounds, for example, compounds having a (meth) acryloyl group are preferable. In the present invention, (meth) acryloyl means acryloyl and/or methacryloyl, and "(meth)" means the same as defined below. Examples of the compound having a (meth) acryloyl group include a (meth) acrylamide derivative having a (meth) acrylamide group and a (meth) acrylate having a (meth) acryloyloxy group. The compound having a (meth) acryloyl group is exemplified below, and various compounds can be selected and used without particular limitation. In the active energy ray-curable adhesive composition of the present invention, the content of the radical polymerizable compound is preferably 10% by weight or more.
Monofunctional radical polymerizable Compound
Examples of the monofunctional radical polymerizable compound include compounds represented by the following general formula (1),
[ chemical formula 1]
Figure BDA0003508333730000051
(wherein, R1Is a hydrogen atom or a methyl group, R2And R3Each independently is a hydrogen atom, an alkyl group, a hydroxyalkyl group, an alkoxyalkyl group or a cyclic ether group, R2And R3Optionally forming a cyclic heterocyclic ring). The number of carbon atoms of the alkyl moiety of the alkyl group, hydroxyalkyl group, and/or alkoxyalkyl group is not particularly limited, and may be, for example, 1 to 4. In addition, R2And R3Examples of the optionally formed cyclic heterocyclic ring include N-acryloylmorpholine.
Specific examples of the compound represented by the general formula (1) include: n-alkyl group-containing (meth) acrylamide derivatives such as N-methyl (meth) acrylamide, N-dimethyl (meth) acrylamide, N-diethyl (meth) acrylamide, N-isopropyl (meth) acrylamide, N-butyl (meth) acrylamide, and N-hexyl (meth) acrylamide; n-hydroxyalkyl (meth) acrylamide-containing derivatives such as N-methylol (meth) acrylamide, N-hydroxyethyl (meth) acrylamide, and N-methylol-N-propyl (meth) acrylamide; and N-alkoxy group-containing (meth) acrylamide derivatives such as N-methoxymethylacrylamide and N-ethoxymethylacrylamide. Examples of the cyclic ether group-containing (meth) acrylamide derivative include heterocyclic ring-containing (meth) acrylamide derivatives in which the nitrogen atom of the (meth) acrylamide group forms a heterocyclic ring, and examples thereof include N-acryloylmorpholine, N-acryloylpiperidine, N-methacryloylpiperidine, and N-acryloylpyrrolidine. Among these, N-hydroxyethyl acrylamide and N-acryloyl morpholine can be suitably used in view of excellent reactivity, obtaining a cured product with a high elastic modulus, and excellent adhesion to a polarizer.
The content of the compound represented by the general formula (1) in the adhesive composition is preferably 1 to 50% by weight, more preferably 3 to 20% by weight, from the viewpoints of improving adhesiveness and water resistance when the polarizer and the transparent protective film are adhered to each other via the adhesive layer, and also improving productivity due to a high polymerization rate. In particular, if the content of the compound represented by the general formula (1) is too large, the water absorption of the cured product may be high, and the water resistance may be deteriorated.
The adhesive composition used in the present invention may contain, as a curable component, other monofunctional radical polymerizable compounds in addition to the compound represented by the general formula (1). Examples of the monofunctional radical polymerizable compound include various (meth) acrylic acid derivatives having a (meth) acryloyloxy group. Specific examples thereof include: methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, 2-methyl-2-nitropropyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, sec-butyl (meth) acrylate, tert-butyl (meth) acrylate, n-pentyl (meth) acrylate, (C1-20) alkyl (meth) acrylates such as t-amyl (meth) acrylate, 3-pentyl (meth) acrylate, 2-dimethylbutyl (meth) acrylate, n-hexyl (meth) acrylate, hexadecyl (meth) acrylate, n-octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, 4-methyl-2-propylpentyl (meth) acrylate, and n-octadecyl (meth) acrylate.
Examples of the (meth) acrylic acid derivative include: cycloalkyl (meth) acrylates such as cyclohexyl (meth) acrylate and cyclopentyl (meth) acrylate; aralkyl (meth) acrylates such as benzyl (meth) acrylate; polycyclic (meth) acrylates such as 2-isobornyl (meth) acrylate, 2-norbornyl methyl (meth) acrylate, 5-norbornen-2-yl methyl (meth) acrylate, 3-methyl-2-norbornyl methyl (meth) acrylate, dicyclopentenyl (meth) acrylate, dicyclopentenyloxyethyl (meth) acrylate, and dicyclopentanyl (meth) acrylate; (meth) acrylic acid esters having an alkoxy group or a phenoxy group such as 2-methoxyethyl (meth) acrylate, 2-ethoxyethyl (meth) acrylate, 2-methoxymethoxyethyl (meth) acrylate, 3-methoxybutyl (meth) acrylate, ethyl carbitol (meth) acrylate, phenoxyethyl (meth) acrylate, and alkylphenoxypolyethylene glycol (meth) acrylate; and so on. When the resin composition of the present invention is used as an adhesive for a polarizing film, the resin composition preferably contains (meth) acrylate containing an alkoxy group or a phenoxy group, such as phenoxyethyl (meth) acrylate, alkylphenoxypolyethylene glycol (meth) acrylate, and 2-hydroxy-3-phenoxypropyl acrylate, from the viewpoint of adhesion to a protective film. The content thereof is preferably 1 to 30% by weight based on the resin composition.
Further, examples of the (meth) acrylic acid derivative include: hydroxyalkyl (meth) acrylates such as 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, 8-hydroxyoctyl (meth) acrylate, 10-hydroxydecyl (meth) acrylate, and 12-hydroxylauryl (meth) acrylate, hydroxy-containing (meth) acrylates such as [4- (hydroxymethyl) cyclohexyl ] methyl acrylate, cyclohexanedimethanol mono (meth) acrylate, and 2-hydroxy-3-phenoxypropyl (meth) acrylate; epoxy group-containing (meth) acrylates such as glycidyl (meth) acrylate and 4-hydroxybutyl (meth) acrylate glycidyl ether; halogen-containing (meth) acrylates such as 2,2, 2-trifluoroethyl (meth) acrylate, 2,2, 2-trifluoroethylethyl (meth) acrylate, tetrafluoropropyl (meth) acrylate, hexafluoropropyl (meth) acrylate, octafluoropentyl (meth) acrylate, heptadecafluorodecyl (meth) acrylate, and 3-chloro-2-hydroxypropyl (meth) acrylate; alkylaminoalkyl (meth) acrylates such as dimethylaminoethyl (meth) acrylate; oxetanyl (meth) acrylates such as 3-oxetanyl methyl (meth) acrylate, 3-methyloxetanyl methyl (meth) acrylate, 3-ethyloxetanyl methyl (meth) acrylate, 3-butyloxetanyl methyl (meth) acrylate, and 3-hexyloxetanyl methyl (meth) acrylate; and (meth) acrylates having a heterocyclic ring such as tetrahydrofurfuryl (meth) acrylate and butyrolactone (meth) acrylate, hydroxypivalic acid neopentyl glycol (meth) acrylic acid adducts, and p-phenylphenol (meth) acrylate. Among them, 2-hydroxy-3-phenoxypropyl acrylate is preferable because it has excellent adhesion to various protective films.
Examples of the monofunctional radical polymerizable compound include: carboxyl group-containing monomers such as (meth) acrylic acid, carboxyethyl acrylate, carboxypentyl acrylate, itaconic acid, maleic acid, fumaric acid, crotonic acid, and isocrotonic acid.
Examples of the monofunctional radical polymerizable compound include: lactam-type vinyl monomers such as N-vinylpyrrolidone, N-vinyl-epsilon-caprolactam and methyl vinyl pyrrolidone; vinylpyridine, vinylpiperidone, vinylpyrimidine, vinylpiperazine, vinylpyrazine, vinylpyrrole, vinylimidazole, vinylpyridine
Figure BDA0003508333730000071
Vinyl monomers having a nitrogen-containing heterocycle such as oxazole and vinyl morpholine.
When a hydroxyl group-containing (meth) acrylate, a carboxyl group-containing (meth) acrylate, a phosphoric acid group-containing (meth) acrylate, or the like having high polarity among the above compounds is contained in the resin composition, the adhesion to various substrates is improved. The content of the hydroxyl group-containing (meth) acrylate is preferably 1 to 30% by weight based on the resin composition. If the content is too large, the water absorption of the cured product may be high, and the water resistance may be deteriorated. The content of the carboxyl group-containing (meth) acrylate is preferably 1 to 20% by weight based on the resin composition. When the content is too large, the optical durability of the polarizing film is lowered, which is not preferable. The phosphoric group-containing (meth) acrylate includes 2- (meth) acryloyloxyethyl acid phosphate, and the content thereof is preferably 0.1 to 10% by weight based on the resin composition. When the content is too large, the optical durability of the polarizing film is lowered, which is not preferable.
As the monofunctional radical polymerizable compound, a radical polymerizable compound having an active methylene group can be used. The radical polymerizable compound having an active methylene group is a compound having an active methylene group and an active double bond group such as a (meth) acryloyl group at a terminal or in a molecule. Examples of the active methylene group include: acetoacetyl, alkoxymalonyl, cyanoacetyl, or the like. The active methylene group is preferably an acetoacetyl group. Specific examples of the radical polymerizable compound having an active methylene group include: acetoacetoxyalkyl (meth) acrylates such as 2-acetoacetoxyethyl (meth) acrylate, 2-acetoacetoxypropyl (meth) acrylate, and 2-acetoacetoxy-1-methylethyl (meth) acrylate; 2-ethoxymalonyloxyethyl (meth) acrylate, 2-cyanoacetoxyethyl (meth) acrylate, N- (2-cyanoacetoxyethyl) acrylamide, N- (2-propionylacetyloxybutyl) acrylamide, N- (4-acetoacetyloxymethylbenzyl) acrylamide, N- (2-acetoacetylaminoethyl) acrylamide and the like. The radical polymerizable compound having an active methylene group is preferably acetoacetoxyalkyl (meth) acrylate.
Polyfunctional radical polymerizable Compound
Further, examples of the bifunctional or higher polyfunctional radical polymerizable compound include: n, N' -methylenebis (meth) acrylamide, tripropylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, 1, 6-hexanediol di (meth) acrylate, 1, 9-nonanediol di (meth) acrylate, 1, 10-decanediol diacrylate as polyfunctional (meth) acrylamide derivativesAcid esters, 2-ethyl-2-butyl propylene glycol di (meth) acrylate, bisphenol A ethylene oxide adduct di (meth) acrylate, bisphenol A propylene oxide adduct di (meth) acrylate, bisphenol A diglycidyl ether di (meth) acrylate, neopentyl glycol di (meth) acrylate, tricyclodecane dimethanol di (meth) acrylate, Cyclic Trimethylolpropane formal (meth) acrylate, and bis (meth) acrylate
Figure BDA0003508333730000081
Esters of (meth) acrylic acids and polyhydric alcohols such as alkanediol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, and EO-modified diglycerol tetra (meth) acrylate, and 9, 9-bis [4- (2- (meth) acryloyloxyethoxy) phenyl]Fluorene, hydroxypivalic acid neopentyl glycol acrylic acid adduct, and the like. Specific examples thereof include ARONIXM-220 (manufactured by Toyo Seisaku-Sho Co., Ltd.), LIGHT ACRYLATE 1,9ND-A (manufactured by Kyowa Kagaku K.K.), LIGHT ACRYLATE DGE-4A (manufactured by Kyowa Kagaku K.K.), LIGHT ACRYLATE DCP-A (manufactured by Kyowa Kagaku K.K.), SR-531 (manufactured by Sartomer Co., Ltd.), and CD-536 (manufactured by Sartomer Co., Ltd.). Further, as necessary, there may be mentioned: various epoxy (meth) acrylates, urethane (meth) acrylates, polyester (meth) acrylates, various (meth) acrylate monomers, and the like. The polyfunctional (meth) acrylamide derivative is preferably contained in the adhesive composition because it has a high polymerization rate and excellent productivity and also has excellent crosslinkability in the case of producing a cured resin composition.
From the viewpoint of satisfying both of the adhesiveness to polarizers and various transparent protective films and the optical durability in a severe environment, it is preferable to use a monofunctional radical polymerizable compound and a polyfunctional radical polymerizable compound in combination as the radical polymerizable compound. Since the monofunctional radical polymerizable compound has a low liquid viscosity, the liquid viscosity of the resin composition can be reduced by adding the monofunctional radical polymerizable compound to the resin composition. Further, the monofunctional radical polymerizable compound often has a functional group that can exhibit various functions, and by including the monofunctional radical polymerizable compound in the resin composition, various functions can be exhibited in the resin composition and/or the cured product of the resin composition. The polyfunctional radical polymerizable compound is preferably contained in the resin composition because it can 3-dimensionally crosslink a cured product of the resin composition. The ratio of the monofunctional radical polymerizable compound to the polyfunctional radical polymerizable compound is preferably in the range of 10 to 1000 parts by weight based on 100 parts by weight of the monofunctional radical polymerizable compound.
< 2: cationically polymerizable adhesive composition >
The cationic polymerizable compound used in the cationic polymerizable adhesive composition can be classified into a monofunctional cationic polymerizable compound having 1 cationic polymerizable functional group in the molecule and a polyfunctional cationic polymerizable compound having 2 or more cationic polymerizable functional groups in the molecule. Since the monofunctional cationic polymerizable compound has a low liquid viscosity, the liquid viscosity of the resin composition can be reduced by adding the monofunctional cationic polymerizable compound to the resin composition. Further, the monofunctional cationic polymerizable compound often has a functional group that can exhibit various functions, and by containing the monofunctional cationic polymerizable compound in the resin composition, various functions can be exhibited in the resin composition and/or the cured product of the resin composition. The polyfunctional cationic polymerizable compound is preferably contained in the resin composition because it can 3-dimensionally crosslink a cured product of the resin composition. The ratio of the monofunctional cationic polymerizable compound to the polyfunctional cationic polymerizable compound is preferably in the range of 10 parts by weight to 1000 parts by weight based on 100 parts by weight of the monofunctional cationic polymerizable compound. Examples of the cationically polymerizable functional group include an epoxy group, an oxetanyl group and a vinyl ether group. The compound having an epoxy group includes an aliphatic epoxy compound, an alicyclic epoxy compound, and an aromatic epoxy compound, and particularly, an alicyclic epoxy compound is preferably contained as the cationically polymerizable adhesive composition of the present invention because of excellent curability and adhesiveness. Examples of the alicyclic epoxy compound include 3, 4-epoxycyclohexylmethyl-3, 4-epoxycyclohexane carboxylate, caprolactone-modified products of 3, 4-epoxycyclohexylmethyl-3, 4-epoxycyclohexane carboxylate, trimethylcaprolactone-modified products, valerolactone-modified products, and the like, and specifically include CELLOXIDE 2021, CELLOXIDE 2021A, CELLOXIDE 2021P, CELLOXIDE 2081, CELLOXIDE 2083, CELLOXIDE 2085 (the above is made by Dailuo Chemical Co., Ltd.), Cyracure UVR-6105, Cyracure UVR-6107, Cyracure 30, R-6110 (the above is made by Dow Chemical Japan Co., Ltd.), jer-828 (the above is made by Japan epoxy resin Co., Ltd.), and the like. The cationic polymerizable adhesive composition of the present invention preferably contains a compound having an oxetanyl group because of its effect of improving curability and reducing liquid viscosity of the composition. Examples of the oxetanyl group-containing compound include 3-ethyl-3-hydroxymethyloxetane, 1, 4-bis [ (3-ethyl-3-oxetanyl) methoxymethyl ] benzene, 3-ethyl-3- (phenoxymethyl) OXETANE, bis [ (3-ethyl-3-oxetanyl) methyl ] ether, 3-ethyl-3- (2-ethylhexyloxymethyl) OXETANE, novolak OXETANE and the like, and ARON OXETANE OXT-101, ARON OXETANE OXT-121, ARON OXETANE OXT-211, ARON OXETANE OXT-221 and ARON OXETANE OXT-212 (available from Toyo Kabushiki Kaisha) are commercially available. The cationic polymerizable adhesive composition of the present invention preferably contains a compound having a vinyl ether group because of its effect of improving curability and reducing liquid viscosity of the composition. Examples of the compound having a vinyl ether group include 2-hydroxyethyl vinyl ether, diethylene glycol monovinyl ether, 4-hydroxybutyl vinyl ether, diethylene glycol monovinyl ether, triethylene glycol divinyl ether, cyclohexanedimethanol monovinyl ether, tricyclodecane vinyl ether, cyclohexyl vinyl ether, methoxyethyl vinyl ether, ethoxyethyl vinyl ether, pentaerythritol-type tetravinyl ether, and the like.
< bubble suppressing agent having reactive group >
The bubble inhibitor is a compound capable of reducing the surface tension by being incorporated into the adhesive composition, and has an effect of reducing bubbles between the adhesive composition and an adherend to be bonded. As the bubble inhibitor, for example: silicone bubble inhibitors having a polysiloxane skeleton such as polydimethylsiloxane, (meth) acrylic bubble inhibitors having a (meth) acryloyl skeleton obtained by polymerizing (meth) acrylic acid esters or the like, polyether bubble inhibitors obtained by polymerizing vinyl ethers, cyclic ethers or the like, fluorine bubble inhibitors comprising fluorine-containing compounds having perfluoroalkyl groups, and the like.
The reactive group of the bubble inhibitor includes a polymerizable functional group, and specifically includes, for example, a radical polymerizable functional group having an olefinic double bond such as a (meth) acryloyl group, a vinyl group, or an allyl group, a cationic polymerizable functional group such as an epoxy group such as a glycidyl group, an oxetane group, a vinyl ether group, a cyclic thioether group, or a lactone group. From the viewpoint of reactivity in the adhesive composition, a bubble suppressing agent having a double bond as a reactive group is preferable, and a bubble suppressing agent having a (meth) acryloyl group is more preferable.
Among the above-mentioned bubble suppressing agents, silicone-based bubble suppressing agents are preferable in consideration of the laminated bubble suppressing effect and the adhesion improving effect. Among the bubble suppressing agents, those containing a urethane bond or an isocyanurate ring structure in the main chain skeleton or side chain are preferable in view of the adhesiveness of the adhesive layer. As the silicone bubble inhibitor, a commercially available product can be suitably used, and examples thereof include BYK-UV3505 (BYK-Chemie Japan) which is an acryl-modified polydimethylsiloxane.
In order to achieve both the adhesive strength of the obtained adhesive layer and the effect of reducing laminated bubbles, the content of the bubble inhibitor is preferably 0.01 to 0.6% by weight, based on 100% by weight of the total amount of the adhesive composition.
< form of radical polymerizable adhesive composition >
When the active energy ray is an electron beam, the adhesive composition does not need to contain a photopolymerization initiator, but when the active energy ray is ultraviolet light or visible light, the adhesive composition preferably contains a photopolymerization initiator.
Photopolymerization initiator
The photopolymerization initiator in the case of using a radical polymerizable compound can be appropriately selected depending on the activation energy ray. In the case of curing by ultraviolet rays or visible light, a photopolymerization initiator that is cleaved by ultraviolet rays or visible light is used. Examples of the photopolymerization initiator include: benzophenone compounds such as benzil, benzophenone, benzoylbenzoic acid, and 3, 3' -dimethyl-4-methoxybenzophenone; aromatic ketone compounds such as 4- (2-hydroxyethoxy) phenyl (2-hydroxy-2-propyl) ketone, α -hydroxy- α, α' -dimethylacetophenone, 2-methyl-2-hydroxypropiophenone, and α -hydroxycyclohexyl phenyl ketone; acetophenone compounds such as methoxyacetophenone, 2-dimethoxy-2-phenylacetophenone, 2-diethoxyacetophenone, and 2-methyl-1- [4- (methylthio) phenyl ] -2-morpholinopropan-1-one; benzoin ether compounds such as benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin butyl ether, and anisoin methyl ether; aromatic ketal compounds such as benzil dimethyl ketal; aromatic sulfonyl chloride compounds such as 2-naphthalenesulfonyl chloride; optically active oximes such as 1-phenyl-1, 1-propanedione-2- (O-ethoxycarbonyl) oxime; thioxanthone compounds such as thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, 2, 4-dimethylthioxanthone, isopropylthioxanthone, 2, 4-dichlorothioxanthone, 2, 4-diethylthioxanthone, 2, 4-diisopropylthioxanthone and dodecylthioxanthone; camphorquinone; a halogenated ketone; acyl phosphine oxides; acyl phosphonates and the like.
The amount of the photopolymerization initiator added is 20 wt% or less based on the total amount of the adhesive composition. The amount of the photopolymerization initiator is preferably 0.01 to 20% by weight, more preferably 0.05 to 10% by weight, and still more preferably 0.1 to 5% by weight.
When the adhesive composition used in the present invention is used for visible light-curing containing a radical polymerizable compound as a curing component, it is particularly preferable to use a photopolymerization initiator having high sensitivity to light of 380nm or more, and a photopolymerization initiator having high sensitivity to light of 380nm or more will be described later.
As the photopolymerization initiator, a compound represented by the following general formula (2); or a combination of a compound represented by the general formula (2) and a photopolymerization initiator having high sensitivity to light of 380nm or more as described later.
[ chemical formula 2]
Figure BDA0003508333730000121
(in the formula, R4And R5represents-H, -CH2CH3-iPr or Cl, R4And R5May be the same or different). When the compound represented by the general formula (2) is used, the adhesiveness is superior to that when a photopolymerization initiator having high sensitivity to light of 380nm or more is used alone. Among the compounds represented by the general formula (2), R is particularly preferred4And R5is-CH2CH3Diethyl thioxanthone (ll). The composition ratio of the compound represented by the general formula (4) in the adhesive composition is preferably 0.1 to 5% by weight, more preferably 0.5 to 4% by weight, and still more preferably 0.9 to 3% by weight, based on the total amount of the adhesive composition.
Further, it is preferable to add a polymerization initiation aid as needed. Examples of the polymerization initiation aid include: triethylamine, diethylamine, N-methyldiethanolamine, ethanolamine, 4-dimethylaminobenzoic acid, methyl 4-dimethylaminobenzoate, ethyl 4-dimethylaminobenzoate, isoamyl 4-dimethylaminobenzoate, etc., with ethyl 4-dimethylaminobenzoate being particularly preferred. When the polymerization initiator aid is used, the amount thereof to be added is usually 0 to 5% by weight, preferably 0 to 4% by weight, and most preferably 0 to 3% by weight, based on the total amount of the adhesive composition.
Further, a known photopolymerization initiator may be used in combination as necessary. Since the transparent protective film having UV absorption ability does not transmit light of 380nm or less, it is preferable to use a photopolymerization initiator having high sensitivity to light of 380nm or more as the photopolymerization initiator. Specifically, there may be mentioned: 2-methyl-1- (4-methylthiophenyl) -2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -1-butanone, 2- (dimethylamino) -2- [ (4-methylphenyl) methyl ] -1- [4- (4-morpholino) phenyl ] -1-butanone, 2,4, 6-trimethylbenzoyldiphenylphosphine oxide, bis (2,4, 6-trimethylbenzoyl) phenylphosphine oxide, bis (. eta.5-2, 4-cyclopentadien-1-yl) bis (2, 6-difluoro-3- (1H-pyrrol-1-yl) phenyl) titanium and the like.
In particular, as the photopolymerization initiator, in addition to the photopolymerization initiator of the general formula (2), a compound represented by the following general formula (3) is preferably further used,
[ chemical formula 3]
Figure BDA0003508333730000131
(in the formula, R6、R7And R8represents-H, -CH3、-CH2CH3-iPr or Cl, R6、R7And R8May be the same or different). As the compound represented by the general formula (3), commercially available 2-methyl-1- (4-methylthiophenyl) -2-morpholinopropan-1-one (trade name: IRGACURE907, manufacturer: BASF) can be suitably used. Further, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -1-butanone (trade name: IRGACURE369, manufacturer: BASF), 2- (dimethylamino) -2- [ (4-methylphenyl) methyl group]-1- [4- (4-morpholinyl) phenyl]1-butanone (trade name: IRGACURE379, manufacturer: BASF) is preferred because of its high sensitivity.
< radically polymerizable Compound having active methylene group and radical polymerization initiator having Hydrogen abstraction Effect >
In the adhesive composition, when a radical polymerizable compound having an active methylene group is used as the radical polymerizable compound, it is preferable to use a radical polymerization initiator having a hydrogen abstraction action in combination. According to this configuration, the adhesiveness of the adhesive layer of the polarizing film is significantly improved even immediately after the polarizing film is taken out from a high-humidity environment or from water (in an undried state). The reason is not clear, but is considered to be the following reason. That is, the radical polymerizable compound having an active methylene group is polymerized together with other radical polymerizable compounds constituting the adhesive layer, and enters the main chain and/or side chain of the base polymer in the adhesive layer to form the adhesive layer. In this polymerization process, if a radical polymerization initiator having a hydrogen abstraction action is present, a base polymer constituting the adhesive layer is formed, and hydrogen is abstracted from a radical polymerizable compound having an active methylene group, thereby generating a radical in the methylene group. The methylene group that generates a radical reacts with a hydroxyl group of a polarizer such as PVA to form a covalent bond between the adhesive layer and the polarizer. As a result, it is presumed that the adhesiveness of the adhesive layer of the polarizing film is significantly improved particularly in a non-dried state.
Examples of the radical polymerization initiator having a hydrogen abstraction action include: thioxanthone radical polymerization initiators, benzophenone radical polymerization initiators, and the like. The radical polymerization initiator is preferably a thioxanthone radical polymerization initiator. Examples of the thioxanthone-based radical polymerization initiator include compounds represented by the above general formula (2). Specific examples of the compound represented by the general formula (2) include: thioxanthone, dimethylthioxanthone, diethylthioxanthone, isopropylthioxanthone, chlorothioxanthone, and the like. Among the compounds represented by the general formula (2), R is particularly preferable4And R5is-CH2CH3Diethyl thioxanthone (ll).
When the adhesive composition contains a radical polymerizable compound having an active methylene group and a radical polymerization initiator having a hydrogen abstraction action, the radical polymerizable compound having an active methylene group and the radical polymerization initiator are preferably contained in an amount of 1 to 50% by weight and 0.1 to 10% by weight, based on the total amount of the curable resin composition, assuming that the total amount of the curable components is 100% by weight.
As described above, in the present invention, a radical is generated from a methylene group of a radical polymerizable compound having an active methylene group in the presence of a radical polymerization initiator having a hydrogen abstraction action, and the methylene group reacts with a hydroxyl group of a polarizer such as PVA to form a covalent bond. Therefore, in order to generate radicals from the methylene group of the radical polymerizable compound having an active methylene group and to form the covalent bond sufficiently, the radical polymerizable compound having an active methylene group is preferably contained in an amount of 1 to 50% by weight, more preferably 3 to 30% by weight, based on 100% by weight of the total amount of the curable components. In order to sufficiently improve the water resistance and the adhesiveness in a non-dried state, it is preferable to set the radical polymerizable compound having an active methylene group to 1% by weight or more. On the other hand, if it exceeds 50 wt%, poor curing of the adhesive layer may occur. The radical polymerization initiator having a hydrogen abstraction action is preferably contained in an amount of 0.1 to 10% by weight, more preferably 0.3 to 9% by weight, based on the total amount of the adhesive composition. In order to sufficiently progress the hydrogen abstraction reaction, it is preferable to use 0.1% by weight or more of a radical polymerization initiator. On the other hand, if it is more than 10% by weight, it may not be completely dissolved in the composition.
< cationic photopolymerization initiator >
The cationically polymerizable adhesive composition contains at least 1 compound selected from the compounds having an epoxy group, oxetane group and vinyl ether group described above as a curable component, and all of them are cured by cationic polymerization, and thus a photo cationic polymerization initiator is blended. The photo cation polymerization initiator generates a cation species or lewis acid by irradiation of active energy rays such as visible light, ultraviolet rays, X-rays, electron beams, etc., thereby initiating a polymerization reaction of an epoxy group or an oxetanyl group. As the photo cation polymerization initiator, a photo acid generator and a photo base generator can be used, and a photo acid generator described later can be suitably used. In addition, in the case of using the adhesive composition used in the present invention as the visible light-curable, it is particularly preferable to use a photo cation polymerization initiator having high sensitivity to light of 380nm or more, but since the photo cation polymerization initiator is a compound which usually exhibits maximum absorption in the vicinity of 300nm or a wavelength region shorter than 300nm, by blending a photosensitizer which exhibits maximum absorption in light of a wavelength region longer than that, specifically, longer than 380nm, it is possible to sense light of a wavelength in the vicinity thereof and promote generation of cationic species or acid from the photo cation polymerization initiator. As the photosensitizer, for example: anthracene compounds, pyrene compounds, carbonyl compounds, organic sulfur compounds, sulfides, redox compounds, azo and diazo compounds, halogen compounds, photoreducing pigments, etc., and these may be mixed with 2 or more of them. Particularly, anthracene compounds are preferable because they are excellent in photosensitizing effect, and specific examples thereof include Anthracure UVS-1331 and Anthracure UVS-1221 (manufactured by Kawasaki Kasei Co., Ltd.). The content of the photosensitizer is preferably 0.1 to 5% by weight, more preferably 0.5 to 3% by weight.
< other ingredients >
The adhesive composition used in the present invention preferably contains the following components.
< acrylic oligomer >
The adhesive composition used in the present invention may contain an acrylic oligomer obtained by polymerizing a (meth) acrylic monomer, in addition to the curable component of the radical polymerizable compound. By containing such a component in the adhesive composition, the curing shrinkage when the composition is cured by irradiation with active energy rays can be reduced, and the interface stress between the adhesive and an adherend such as a polarizer and a transparent protective film can be reduced. As a result, the adhesive layer can be prevented from being deteriorated in adhesiveness to the adherend. In order to sufficiently suppress the curing shrinkage of the cured product layer (adhesive layer), the content of the acrylic oligomer is preferably 20% by weight or less, and more preferably 15% by weight or less, relative to the total amount of the adhesive composition. When the content of the acrylic oligomer in the adhesive composition is too large, the reaction rate when the composition is irradiated with an active energy ray may be rapidly decreased, and curing may be deteriorated. On the other hand, the acrylic oligomer is preferably contained in an amount of 3 wt% or more, more preferably 5 wt% or more, based on the total amount of the adhesive composition.
In view of workability and uniformity in coating, the adhesive composition preferably has a low viscosity, and therefore, an acrylic oligomer obtained by polymerizing a (meth) acrylic monomer is also preferably low in viscosity. The acrylic oligomer having a low viscosity and capable of preventing curing shrinkage of the adhesive layer preferably has a weight average molecular weight (Mw) of 15000 or less, more preferably 10000 or less, and particularly preferably 5000 or less. On the other hand, in order to sufficiently suppress curing shrinkage of the cured product layer (adhesive layer), the weight average molecular weight (Mw) of the acrylic oligomer is preferably 500 or more, more preferably 1000 or more, and particularly preferably 1500 or more. Specific examples of the (meth) acrylic monomer constituting the acrylic oligomer include: methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, 2-methyl-2-nitropropyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, sec-butyl (meth) acrylate, tert-butyl (meth) acrylate, n-pentyl (meth) acrylate, (C1-20) alkyl (meth) acrylates such as t-amyl (meth) acrylate, 3-pentyl (meth) acrylate, 2-dimethylbutyl (meth) acrylate, n-hexyl (meth) acrylate, hexadecyl (meth) acrylate, n-octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, 4-methyl-2-propylpentyl (meth) acrylate, and n-octadecyl (meth) acrylate; and for example: cycloalkyl (meth) acrylates (e.g., cyclohexyl (meth) acrylate, cyclopentyl (meth) acrylate, etc.), (aralkyl (meth) acrylates (e.g., benzyl (meth) acrylate, etc.), polycyclic (meth) acrylates (e.g., 2-isobornyl (meth) acrylate, 2-norbornyl methyl (meth) acrylate, 5-norbornen-2-ylmethyl (meth) acrylate, 3-methyl-2-norbornyl methyl (meth) acrylate, etc.), hydroxyl-containing (meth) acrylates (e.g., 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2, 3-dihydroxypropylmethylbutyl (meth) acrylate, etc.), alkoxy-or phenoxy-containing (meth) acrylates ((2-methoxyethyl (meth) acrylate, 2-methoxypropyl (meth) acrylate, etc.), 2-ethoxyethyl (meth) acrylate, 2-methoxymethoxyethyl (meth) acrylate, 3-methoxybutyl (meth) acrylate, ethylcarbitol (meth) acrylate, phenoxyethyl (meth) acrylate, and the like, epoxy group-containing (meth) acrylates (e.g., glycidyl (meth) acrylate), halogen-containing (meth) acrylates (e.g., 2,2, 2-trifluoroethyl (meth) acrylate), 2,2, 2-trifluoroethyl ethyl (meth) acrylate, tetrafluoropropyl (meth) acrylate, hexafluoropropyl (meth) acrylate, octafluoropentyl (meth) acrylate, heptadecafluorodecyl (meth) acrylate, etc.), alkylaminoalkyl (meth) acrylates (e.g., dimethylaminoethyl (meth) acrylate, etc.), and the like. These (meth) acrylates may be used singly or in combination of 2 or more. Specific examples of the acrylic oligomer include "ARUFON" manufactured by Toyo Seisaku-Shokusho, "Actflow" manufactured by Sudoku-Shokusho K.K., and "JONCRYL" manufactured by BASF Japan K.K.
< photoacid Generator >
The adhesive composition may contain a photoacid generator. When the photoacid generator is contained in the adhesive composition, the water resistance and durability of the adhesive layer can be greatly improved as compared with the case where the photoacid generator is not contained. The photoacid generator can be represented by the following general formula (4).
General formula (4)
[ chemical formula 4]
L+X-
(wherein, L+Means of being arbitrary
Figure BDA0003508333730000161
A cation. In addition, X-Is selected from PF66 -、SbF6 -、AsF6 -、SbCl6 -、BiCl5 -、SnCl6 -、ClO4 -Dithiocarbamate anions, SCN-The counter anion of (1). )
Next, for the counter anion X in the general formula (4)-The description is given.
A counter anion X in the general formula (4)-In principle, it is not particularly limited, but a non-nucleophilic anion is preferable. At counter anion X-In the case of a non-nucleophilic anion, a cation coexisting in the molecule and a nucleophilic reaction in various materials used in combination are less likely to occur, and as a result, the stability with time of the photoacid generator itself represented by the general formula (4) and a composition using the photoacid generator can be improved. The term "non-nucleophilic anion" as used herein means an anion having a low ability to cause nucleophilic reaction. Such an anion includes PF66 -、SbF6 -、AsF6 -、SbCl6 -、BiCl5 -、SnCl6 -、ClO4 -Dithiocarbamate anion, SCN-And the like.
Specifically, preferable examples of the photoacid generator of the present invention include "CYRACURE UVI-6992", "CYRACURE UVI-6974" (manufactured by Dow Chemical Japan, supra), "ADEKA OPTOMER SP 150", "ADEKA OPTOMER SP 152", "ADEKA OPTOMER SP 170", "ADEKA OPTOMER SP 172" (manufactured by ADEKA corporation), "IRGACURE 250" (manufactured by Ciba specialty Chemicals), "CI-2", "CI-2855" (manufactured by Nippon Kagaku K.K.), "Sanaid SI-60L", "Sanaid SI-80L", "Sanaid SI-100L", "Sanaid SI-110L" and "Sanaid SI-180L" (manufactured by Sanxin Chemical Co., Ltd., "Sanxin" 100P "," Sanxin CPI-100A "(manufactured by Co., Ltd.)," Sanxin Apro-100P "(manufactured by Co., Ltd.)," the "CPI-100A", and "CPI-100O" (manufactured by Dow Corp Co., Ltd., "the same"), "WPI-069", "WPI-113", "WPI-116", "WPI-041", "WPI-044", "WPI-054", "WPI-055", "WPAG-281", "WPAG-567" and "WPAG-596" (manufactured by Wako pure chemical industries, Ltd.).
The content of the photoacid generator is 10 wt% or less, preferably 0.01 to 10 wt%, more preferably 0.05 to 5 wt%, and particularly preferably 0.1 to 3 wt% with respect to the total amount of the adhesive composition.
< photobase generator >
The photobase generator is a compound that changes the molecular structure or cleaves the molecule by irradiation with light such as ultraviolet light or visible light to generate 1 or more basic substances that function as a catalyst for the polymerization reaction of a radical polymerizable compound or an epoxy resin. Examples of the basic substance include secondary amines and tertiary amines. Examples of the photobase generator include the α -aminoacetophenone compound described above, the oxime ester compound described above, and a compound having a substituent such as an acyloxyimino group, an N-formylated aromatic amino group, an N-acylated aromatic amino group, a nitrobenzylcarbamate group, or an alkoxybenzylcarbamate group. Among them, oxime ester compounds are preferable.
Examples of the acyloxyimino group-containing compound include: o, O '-succinic acid diphenyl acetoxime, O' -succinic acid dinaphthobenzene oxime, and diphenyl ketone oxime acrylate-styrene copolymer.
Examples of the compound having an N-formylated aromatic amino group and an N-acylated aromatic amino group include: di-N- (p-formylamino) diphenylmethane, di-N- (p-acetylamino) diphenylmethane, di-N- (p-benzoylamino) diphenylmethane, 4-formylaminostilbene, 4-acetylaminostilbene, 2, 4-diformylaminostilbene, 1-formylaminonaphthalene, 1-acetylaminonaphthalene, 1, 5-diformylaminonaphthalene, 1-formylaminoanthracene, 1, 4-diformylaminoanthracene, 1-acetylaminoanthracene, 1, 4-diformylaminoanthraquinone, 1, 5-diformylaminoanthraquinone, 3 ' -dimethyl-4, 4 ' -diformylaminobiphenyl, 4 ' -diformylaminobenzophenone.
Examples of the compound having a nitrobenzyl carbamate group and an alkoxybenzyl carbamate group include: bis { (2-nitrobenzyl) oxy } carbonyl } diaminodiphenylmethane, 2, 4-bis { (2-nitrobenzyl) oxy } stilbene, bis { (2-nitrobenzyloxy) carbonyl } hexane-1, 6-diamine, o-xylidine { (2-nitro-4-chlorobenzyl) oxy } amide }.
The photobase generator is preferably at least any 1 selected from an oxime ester compound and an alpha-aminoacetophenone compound, and more preferably an oxime ester compound. As the α -aminoacetophenone compound, an α -aminoacetophenone compound having 2 or more nitrogen atoms is particularly preferable.
As other photobase generators, WPBG-018 (trade name, 9-anthrylmethyl-N, N' -diethylcarbamate), WPBG-027 (trade name, (E) -1- [3- (2-hydroxyphenyl) -2-acryloyl ] piperidine ((E) -1- [3- (2-hydroxyphenyl) -2-propenoyl ] piperidine)), and photobase generators such as WPBG-082 (trade name, guanidinium2- (3-benzoylphenyl) propionate 2- (3-benzoylphenyl) propionate), WPBG-140 (trade name, 1- (anthraquinone-2-yl) ethylimidazolium carboxylate (1- (anthraquinon-2-yl) ethyl imidazolium carboxylate)).
< Compound containing either alkoxy group or epoxy group >
In the adhesive composition, a photoacid generator and a compound containing either an alkoxy group or an epoxy group may be used in combination in the adhesive composition.
(Compound having epoxy group and Polymer)
When a compound having 1 or more epoxy groups in the molecule or a polymer (epoxy resin) having 2 or more epoxy groups in the molecule is used, a compound having 2 or more functional groups reactive with epoxy groups in the molecule may be used in combination. Examples of the functional group reactive with an epoxy group include: carboxyl group, phenolic hydroxyl group, mercapto group, aromatic primary amino group, aromatic secondary amino group, and the like. In view of 3-dimensional curability, it is particularly preferable to have 2 or more of these functional groups in one molecule.
Examples of the polymer having 1 or more epoxy groups in the molecule include epoxy resins including bisphenol A type epoxy resins derived from bisphenol A and epichlorohydrin, bisphenol F type epoxy resins derived from bisphenol F and epichlorohydrin, bisphenol S type epoxy resins, phenol novolac type epoxy resins, cresol novolac type epoxy resins, bisphenol A novolac type epoxy resins, bisphenol F novolac type epoxy resins, alicyclic epoxy resins, diphenyl ether type epoxy resins, hydroquinone type epoxy resins, naphthalene type epoxy resins, biphenyl type epoxy resins, fluorene type epoxy resins, 3-functional epoxy resins, polyfunctional epoxy resins such as 4-functional epoxy resins, glycidyl ester type epoxy resins, glycidyl amine type epoxy resins, hydantoin type epoxy resins, isocyanurate type epoxy resins, aliphatic chain epoxy resins, and the like, these epoxy resins may be halogenated or hydrogenated. Examples of commercially available epoxy resin products include: JER COAT828, 1001, 801N, 806, 807, 152, 604, 630, 871, YX8000, YX8034, YX4000, Epiclon 830, EXA835LV, HP4032D, HP820, EP4100 series, EP4000 series, EPU series, CELLOXIDE series (2021, 2021P, 2083, 2085, 3000, etc.) manufactured by DIC corporation, Epolead series, EHPE series, YD series, YDF series, YDCN series, YDB series, phenoxy resins (polyhydroxy polyethers synthesized from bis and epichlorohydrin and having epoxy groups at both ends; YP series, etc.) manufactured by Nagase corporation, DENACOL series manufactured by Synese chemical corporation, GHT series manufactured by Synesel corporation, but not limited thereto. These epoxy resins may be used in combination of 2 or more.
(Compound having alkoxy group and Polymer)
The compound having an alkoxy group in the molecule is not particularly limited as long as it has 1 or more alkoxy groups in the molecule, and known compounds can be used. Such compounds are typically exemplified by melamine compounds, amino resins, silane coupling agents, and the like.
The amount of the compound containing either an alkoxy group or an epoxy group is usually 30% by weight or less based on the total amount of the adhesive composition, and if the content of the compound in the composition is too large, the adhesiveness is lowered and the impact resistance in the drop weight test may be deteriorated. The content of the compound in the composition is more preferably 20% by weight or less. On the other hand, from the viewpoint of water resistance, the compound is contained in the composition in an amount of preferably 2% by weight or more, more preferably 5% by weight or more.
< silane coupling agent >
When the adhesive composition used in the present invention is active energy ray-curable, it is preferable to use an active energy ray-curable compound as the silane coupling agent, but the same water resistance can be provided even if the silane coupling agent is not active energy ray-curable.
Specific examples of the silane coupling agent include compounds curable with actinic energy rays such as vinyltrichlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane, 2- (3, 4-epoxycyclohexyl) ethyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyltriethoxysilane, p-styryltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropyltriethoxysilane, and 3-acryloxypropyltrimethoxysilane.
3-methacryloxypropyltrimethoxysilane and 3-acryloxypropyltrimethoxysilane are preferred.
Specific examples of the non-active energy ray-curable silane coupling agent include silane coupling agents having an amino group (D1). Specific examples of the silane coupling agent having an amino group (D1) include gamma-aminopropyltrimethoxysilane, gamma-aminopropyltriethoxysilane, gamma-aminopropyltriisopropoxysilane, gamma-aminopropylmethyldimethoxysilane, gamma-aminopropylmethyldiethoxysilane, gamma- (2-aminoethyl) aminopropyltrimethoxysilane, gamma- (2-aminoethyl) aminopropylmethyldimethoxysilane, gamma- (2-aminoethyl) aminopropyltriethoxysilane, gamma- (2-aminoethyl) aminopropylmethyldiethoxysilane, gamma- (2-aminoethyl) aminopropyltriisopropoxysilane, gamma- (2- (2-aminoethyl) aminopropyltrimethoxysilane, gamma- (2-aminoethyl) aminopropyltrimethoxysilane, gamma-aminopropyltriethoxysilane, gamma-aminopropyl-triethoxysilane, gamma-aminopropyl-trimethoxysilane, gamma-2-aminopropyl-trimethoxysilane, gamma-n-propyltrimethoxysilane, gamma-aminopropyl-methyldimethoxysilane, gamma-aminopropyl-methyldiethoxysilane, gamma-amino-propyltrimethoxysilane, gamma-isopropyltrimethoxysilane, gamma-or a-isopropyltrimethoxysilane, or a mixture of two or of a mixture of two or of a mixture of two or a mixture of, Gamma- (6-aminohexyl) aminopropyltrimethoxysilane, 3- (N-ethylamino) -2-methylpropyltrimethoxysilane, gamma-ureidopropyltrimethoxysilane, gamma-ureidopropyltriethoxysilane, N-phenyl-gamma-aminopropyltrimethoxysilane, N-benzyl-gamma-aminopropyltrimethoxysilane, amino-containing silanes such as N-vinylbenzyl-gamma-aminopropyltriethoxysilane, N-cyclohexylaminomethyltriethoxysilane, N-cyclohexylaminomethyldiethoxymethylsilane, N-phenylaminomethyltrimethoxysilane, (2-aminoethyl) aminomethyltrimethoxysilane, and N, N' -bis [3- (trimethoxysilyl) propyl ] ethylenediamine; ketimine-type silanes such as N- (1, 3-dimethylbutylidene) -3- (triethoxysilyl) -1-propylamine.
The silane coupling agent having an amino group (D1) may be used alone in 1 kind or in combination of two or more kinds. Of these, γ -aminopropyltrimethoxysilane, γ - (2-aminoethyl) aminopropylmethyldimethoxysilane, γ - (2-aminoethyl) aminopropyltriethoxysilane, γ - (2-aminoethyl) aminopropylmethyldiethoxysilane and N- (1, 3-dimethylbutylidene) -3- (triethoxysilyl) -1-propylamine are preferable for ensuring good adhesion.
The amount of the silane coupling agent is preferably in the range of 0.01 to 20 wt%, more preferably 0.05 to 15 wt%, and still more preferably 0.1 to 10 wt% based on the total amount of the adhesive composition. This is because the storage stability of the adhesive composition is deteriorated when the amount is more than 20% by weight, and it is difficult to sufficiently exhibit the effect of the adhesive water resistance when the amount is less than 0.1% by weight.
Specific examples of the non-active energy ray-curable silane coupling agent other than the above include 3-ureidopropyltriethoxysilane, 3-chloropropyltrimethoxysilane, 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropyltrimethoxysilane, bis (triethoxysilylpropyl) tetrasulfide, 3-isocyanatopropyltriethoxysilane, and imidazolesilane.
< Compound having vinyl Ether group >
When the adhesive composition used in the present invention contains a compound having a vinyl ether group, the adhesion between the polarizer and the adhesive layer is preferably improved in water resistance. The reason for obtaining this effect is not clear, but it is presumed that one of the reasons is that the adhesion between the polarizer and the adhesive layer is improved by the interaction between the vinyl ether group of the compound and the polarizer. In order to further improve the water resistance of adhesion between the polarizer and the adhesive layer, the compound is preferably a radical polymerizable compound having a vinyl ether group. The content of the compound is preferably 0.1 to 19 wt% based on the total amount of the adhesive composition.
< Compound producing keto-enol tautomerism >
The adhesive composition used in the present invention may contain a compound that causes keto-enol tautomerism. For example, in an adhesive composition containing a crosslinking agent or an adhesive composition that can be used in combination with a crosslinking agent, a mode including the compound that causes keto-enol tautomerism can be preferably employed. This can suppress excessive viscosity increase, gelation, and formation of a microgel product in the adhesive composition after the organometallic compound is compounded, and can achieve the effect of extending the pot life of the composition.
As the above-mentioned compound which causes keto-enol tautomerism, various β -dicarbonyl compounds can be used. Specific examples thereof include β -diketones such as acetylacetone, 2, 4-hexanedione, 3, 5-heptanedione, 2-methylhexane-3, 5-dione, 6-methylheptane-2, 4-dione, and 2, 6-dimethylheptane-3, 5-dione; acetoacetic acid esters such as methyl acetoacetate, ethyl acetoacetate, isopropyl acetoacetate, and tert-butyl acetoacetate; propionyl acetic acid esters such as propionyl ethyl acetate, propionyl isopropyl acetate, propionyl tert-butyl acetate, and the like; isobutyrylacetic acid esters such as ethyl isobutyrylacetate, isopropyl isobutyrylacetate, and tert-butyl isobutyrylacetate; malonic esters such as methyl malonate and ethyl malonate; and so on. Among these, acetylacetone and acetoacetates are preferable. The compound which causes keto-enol tautomerism may be used alone, or 2 or more compounds may be used in combination.
The amount of the compound which causes keto-enol tautomerism can be, for example, 0.05 to 10 parts by weight, and preferably 0.2 to 3 parts by weight (for example, 0.3 to 2 parts by weight) relative to 1 part by weight of the organometallic compound. If the amount of the above compound is less than 0.05 part by weight based on 1 part by weight of the organometallic compound, it may be difficult to exhibit sufficient effects in use. On the other hand, if the amount of the compound used is more than 10 parts by weight based on 1 part by weight of the organometallic compound, the interaction with the organometallic compound may be excessive, and it may be difficult to develop the intended water resistance.
< Polyrotaxane >
The adhesive composition of the present invention may contain polyrotaxane. The polyrotaxane has a cyclic molecule, a linear molecule passing through an opening of the cyclic molecule, and a chain blocking group disposed at each end of the linear molecule so that the cyclic molecule is not detached from the linear molecule. The cyclic molecule preferably has an active energy ray-curable functional group.
The cyclic molecule is not particularly limited as long as it has an opening part enclosing a linear molecule in a string form, can move on the linear molecule, and has an active energy ray-polymerizable group. In the present specification, the term "cyclic" of a "cyclic molecule" means substantially "cyclic". That is, the cyclic molecule may not be completely closed as long as it can move on the linear molecule.
Specific examples of the cyclic molecule include cyclic polymers such as cyclic polyethers, cyclic polyesters, cyclic polyetheramines, and cyclic polyamines, and cyclodextrins such as α -cyclodextrin, β -cyclodextrin, and γ -cyclodextrin. Among these, cyclodextrins such as α -cyclodextrin, β -cyclodextrin, and γ -cyclodextrin, which are relatively easily available and can be selected from a large number of types of capping groups, are preferable. The cyclic molecule may be present in a mixture of 2 or more kinds in the polyrotaxane or the binder.
In the polyrotaxane used in the present invention, the cyclic molecule has an active energy ray-polymerizable group. Thus, the polyrotaxane reacts with the active energy ray-curable component, and the adhesive whose crosslinking point moves even after curing can be obtained. The active energy ray-polymerizable group of the cyclic molecule may be any group that can be polymerized with the active energy ray-curable compound, and examples thereof include radical-polymerizable groups such as a (meth) acryloyl group and a (meth) acryloyloxy group.
When cyclodextrin is used as the cyclic molecule, it is preferable to introduce an active energy ray-polymerizable group to a hydroxyl group of cyclodextrin via an arbitrary appropriate linker. The number of active energy ray-polymerizable groups in 1 molecule of polyrotaxane is preferably 2 to 1280, more preferably 50 to 1000, and further preferably 90 to 900.
It is preferable to introduce a hydrophobic modification group into the cyclic molecule. By introducing a hydrophobic modification group, the compatibility with the active energy ray-curable component can be improved. Further, since the polarizing film is provided with hydrophobicity, when used for a polarizing film, water can be prevented from entering the interface between the adhesive layer and the polarizer, and water resistance can be further improved. Examples of the hydrophobic modification group include a polyester chain, a polyamide chain, an alkyl chain, an oxyalkylene chain, and an ether chain. Specific examples thereof include those described in [0027] to [0042] of WO 2009/145073.
Polarizing films using a polyrotaxane-containing resin composition as an adhesive have excellent water resistance. The reason why the water resistance of the polarizing film is improved is not known, but is presumed as follows. That is, it is considered that the crosslinked points can move due to the mobility of the cyclic molecules of the polyrotaxane (so-called pulley effect), thereby imparting flexibility to the cured adhesive and increasing the adhesion to the surface irregularities of the polarizer, and as a result, water is prevented from entering the interface between the polarizer and the adhesive layer. Further, it is considered that the hydrophobic property can be imparted to the adhesive by imparting a hydrophobic property to the polyrotaxane, which also contributes to preventing water from entering the interface between the polarizer and the adhesive layer.
The content of the polyrotaxane is preferably 2 to 50% by weight based on the resin composition.
The adhesive composition may contain a compound represented by the following general formula (5):
[ chemical formula 5]
Figure BDA0003508333730000231
(wherein X is a functional group containing at least 1 reactive group selected from the group consisting of a vinyl group, (meth) acryloyl group, styryl group, (meth) acrylamide group, vinyl ether group, epoxy group, oxetanyl group and mercapto group, and R is9And R10Each independently represents a hydrogen atom, an optionally substituted aliphatic hydrocarbon group, an aryl group, or a heterocyclic group). The compound represented by the general formula (5) is likely to form an ester bond with a hydroxyl group of a polyvinyl alcohol polarizer. The compound represented by the above general formula (5) further has X containing a reactive group, and reacts with other curable components contained in the adhesive composition through the reactive group contained in X. That is, the boric acid group and/or boric acid ester group of the curable resin layer and the hydroxyl group of the polarizer are strongly bonded by a covalent bond. Thus, even if moisture is present at the interface between the polarizer and the curable resin layer, these groups strongly interact with each other not only by hydrogen bonds and/or ionic bonds but also by covalent bonds, and therefore, the adhesion water resistance between the polarizer and the curable resin layer is dramatically improved. From the viewpoint of improving the adhesiveness and water resistance between the polarizer and the cured product layer, particularly the adhesiveness and water resistance when the polarizer and the transparent protective film are adhered to each other via the adhesive layer, the content of the compound represented by the general formula (5) in the adhesive composition is preferably 0.001 to 50% by weight, more preferably 0.1 to 30% by weight, and most preferably 1 to 10% by weight.
< organometallic Compound >
When the adhesive composition of the present invention contains at least 1 organic metal compound selected from the group consisting of metal alkoxides and metal chelates, and a polymerizable compound having a polymerizable functional group and a carboxyl group, the adhesion between the polarizer and the adhesive layer is preferably improved in water resistance. The organic metal compound becomes an active metal species due to inclusion of moisture, and as a result, the organic metal compound strongly interacts with both the polarizer and the active energy ray-curable component constituting the adhesive layer. Thus, even if moisture is present at the interface between the polarizer and the adhesive layer, the polarizer and the adhesive layer strongly interact with each other via the organometallic compound, and therefore the adhesion water resistance between the polarizer and the adhesive layer is dramatically improved. Although the organometallic compound contributes significantly to the improvement of the adhesiveness and water resistance of the adhesive layer, the composition containing the organometallic compound tends to have a shorter pot life and lower productivity because the liquid stability becomes unstable. One of the reasons for this is that the organometallic compound has high reactivity and comes into contact with water contained in a small amount in the composition to cause hydrolysis reaction and self-condensation reaction, resulting in self-aggregation and clouding of the composition liquid (generation of aggregates, phase separation, precipitation). However, when the composition contains the organometallic compound and the polymerizable compound having a polymerizable functional group and a carboxyl group, the hydrolysis reaction and the self-condensation reaction of the organometallic compound can be suppressed, and the liquid stability of the organometallic compound in the composition can be dramatically improved. The proportion of the organometallic compound is preferably 0.05 to 15% by weight, more preferably 0.1 to 10% by weight, based on the total composition. If the amount is more than 15 wt%, the storage stability of the composition is deteriorated, and the ratio of the component for adhesion to the polarizer and the protective film is relatively insufficient, which may result in a decrease in adhesion. In addition, when the amount is less than 0.05% by weight, the effect of the adhesive water resistance cannot be sufficiently exhibited, and therefore, when the total amount of the organic metal compounds in the curable adhesive composition is α (mol), the content of the polymerizable compound having a polymerizable functional group and a carboxyl group is preferably 0.25 α (mol) or more, more preferably 0.35 α (mol) or more, and particularly preferably 0.5 α (mol) or more. When the content of the polymerizable compound having a polymerizable functional group and a carboxyl group is less than 0.25 α (mol), the stabilization of the organic metal compound becomes insufficient, and hydrolysis reaction and self-condensation reaction proceed, and the pot life may be shortened. The upper limit of the content of the polymerizable compound relative to the total amount α (mol) of the organometallic compounds is not particularly limited, and may be, for example, about 4 α (mol).
< chlorinated polyolefin >
The adhesive composition of the present invention may contain a chlorinated polyolefin. In this case, the resultant adhesive layer has a remarkably reduced staining property due to the iodine compound derived from the polyvinyl alcohol polarizer, and functions as a protective layer for preventing the iodine compound from being released from and diffused into the polarizer. As a result, when the adhesive composition of the present invention is used for polarizing films, the optical durability of the polarizing films is significantly improved. The adhesive composition of the present invention is required to be optically transparent, and it is preferable to select a chlorinated polyolefin as the polyolefin-based resin, which is soluble in the active energy ray-curable component and does not undergo layer separation or precipitation. The polyolefin not chlorinated is not preferable because it has significantly low solubility in a curable component cured by irradiation with an active energy ray.
Examples of the chlorinated polyolefin usable in the present invention include chlorinated polyethylene, chlorinated polypropylene, acrylic-modified or urethane-modified chlorinated polyolefin, and the like.
The content of chlorine in the chlorinated polyolefin is preferably 25 to 50% by weight, more preferably 30 to 45% by weight. When the content is less than 25% by weight, the solubility in the active energy ray-curable component may be lowered, and it may be difficult to form an optically transparent composition. If the amount exceeds 50% by weight, the change in optical properties under severe humidification conditions when a polarizing film is produced becomes large, and the effects of the present invention may not be obtained. The chlorine content in the chlorinated polyolefin can be measured according to JIS-K7229. More specifically, for example, the measurement can be carried out by an "oxygen bottle combustion method" in which a chlorine-containing resin is burned under an oxygen atmosphere, and the generated gaseous chlorine is absorbed by water and quantified by titration.
In addition, chlorinated polyolefins having a weight average molecular weight preferably in the range of 3000 to 100000, more preferably 5000 to 80000, and most preferably 10000 to 20000 can be used. If the molecular weight of the chlorinated polyolefin is too low, the water resistance may not be sufficiently improved when the chlorinated polyolefin is produced into a cured product. If the molecular weight is too high, the solubility in the active energy ray-curable component may be significantly reduced, and it may be difficult to form an optically transparent composition.
As chlorinated polyolefins that are available as commercial products, for example: superclon series (manufactured by Nippon paper chemical Co., Ltd.), Hardren series (manufactured by Toyo Boseki Co., Ltd.), ELASLEN series (manufactured by Showa Denko K.K.), etc.
Among chlorinated polyolefins available as commercial products, use of "Superclon 814 HS", "Superclon 390S", "Superclon 803 MW", "Superclon 803L", "Superclon B" of the Superclon series (manufactured by japan paper chemical corporation) and "Hardren 16-LP", "Hardren 15-LP" of the Hardren series (manufactured by toyobo co.), and "ELASLEN 404B", "ELASLEN 402B", "ELASLEN 401A" of the elan series (manufactured by showa electric corporation) and the like, particularly "Superclon 814 HS" are more preferable because they are excellent in balance between solubility of active energy ray-curable components and stability of optical characteristics under severe humidification conditions when a polarizing film is produced, and thus can be used more preferably.
< additives other than the above >
In addition, various additives may be added to the adhesive composition used in the present invention as other optional components within a range not impairing the object and effect of the present invention. Examples of the additive include polymers or oligomers such as epoxy resins, polyamides, polyamideimides, polyurethanes, polybutadienes, polychloroprenes, polyethers, polyesters, styrene-butadiene block copolymers, petroleum resins, xylene resins, ketone resins, cellulose resins, fluorine-based oligomers, silicone-based oligomers, and polythioether-based oligomers; polymerization inhibitors such as phenothiazine and 2, 6-di-tert-butyl-4-methylphenol; a polymerization initiation aid; a surfactant; a plasticizer; an ultraviolet absorber; an inorganic filler; a pigment; dyes, and the like.
The additive is usually 0 to 10% by weight, preferably 0 to 5% by weight, and most preferably 0 to 3% by weight, based on the total amount of the adhesive composition.
< adhesive composition for polarizing film >
In order to effectively suppress the generation of lamination bubbles, the surface tension of the adhesive composition for a polarizing film of the present invention before curing is preferably 30mN/m or less. The method for measuring the surface tension of the adhesive composition before curing will be described later.
In the adhesive composition for a polarizing film of the present invention, when a cured product obtained by curing the composition is immersed in pure water at 23 ℃ for 24 hours, the volume water absorption is preferably 10% by weight or less, and the volume water absorption is represented by the following formula.
Formula (II): { (M2-M1)/M1 }. times.100 (%),
wherein, M1: weight of cured product before immersion, M2: weight of cured product after immersion
By setting the volume water absorption rate to 10 wt% or less, it is possible to suppress the migration of water to the polarizer when the polarizing film is placed in a severe high-temperature and high-humidity environment, and it is possible to suppress the increase in transmittance and the decrease in polarization degree of the polarizer. The volume water absorption of the adhesive layer of the polarizing film is preferably 5 wt% or less, more preferably 3 wt% or less, and most preferably 1 wt% or less, from the viewpoint of improving optical durability in a severe environment at high temperatures. On the other hand, when the polarizer and the transparent protective film are bonded, a certain amount of moisture is retained in the polarizer, and when the curable adhesive comes into contact with the moisture contained in the polarizer, appearance defects such as shrinkage cavities and bubbles may occur. In order to suppress the appearance defect, the curable adhesive preferably absorbs a certain amount of moisture. More specifically, the volume water absorption is preferably 0.01 wt% or more, and more preferably 0.05 wt% or more.
The viscosity of the adhesive composition used in the present invention is preferably 3 to 100 mPas, more preferably 5 to 50 mPas, and most preferably 10 to 30 mPas. When the viscosity of the adhesive composition is high, the surface smoothness after application is insufficient, and appearance defects occur, which is not preferable. The adhesive composition used in the present invention may be applied after the composition is heated or cooled to adjust the viscosity to a preferred range.
The adhesive composition of the present invention preferably has a high octanol/water partition coefficient (hereinafter referred to as logPow value). The logPow value is an index indicating the lipophilicity of a substance and is a logarithmic value of the partition coefficient of octanol/water. A high logPow means lipophilicity, i.e. a low water absorption. The logPow value can also be measured (by the flask immersion method described in JIS-Z-7260), and can be calculated by calculation based on the structure of each compound as a constituent component (curable component or the like) of the curable adhesive for polarizing films. In the present specification, a logPow value calculated by ChemDraw Ultra manufactured by cambridge soft corporation is used.
Based on the above calculated values, the logPow value of the curable adhesive for a polarizing film in the present invention can be calculated by the following formula.
logPow ═ Σ (logPowi × Wi) of curable adhesive
logPowi: logPow value of each component of curable adhesive
Wi: (number of moles of component i)/(total number of moles of components of the curable adhesive)
In the above calculation, the components that do not form the skeleton of the cured product (adhesive layer), such as the polymerization initiator and the photoacid generator, among the components of the curable adhesive are removed from the components in the above calculation. The logPow value of the curable adhesive for polarizing films of the present invention is preferably 1 or more, more preferably 1.5 or more, and most preferably 2 or more. This improves the water resistance and moisture resistance of the adhesive. On the other hand, the logPow value of the curable adhesive for polarizing films of the present invention is usually about 8 or less, preferably 5 or less, and more preferably 4 or less. If the logPow value is too high, poor appearance such as shrinkage cavity and air bubbles is likely to occur as described above, which is not preferable.
Further, it is preferable that the adhesive composition of the present invention contains substantially no water or volatile solvent. By substantially not containing a volatile solvent, heat treatment is not required, and not only productivity is excellent, but also deterioration in optical characteristics of the polarizer due to heat can be suppressed, which is preferable. "substantially not contained" means that the content is less than 5% by weight, particularly less than 2% by weight, when the total amount of the adhesive composition is 100% by weight or less, for example.
The adhesive composition is preferably selected so that the Tg of the cured product layer formed therefrom, particularly the adhesive layer, is 60 ℃ or higher, more preferably 70 ℃ or higher, even more preferably 75 ℃ or higher, even more preferably 100 ℃ or higher, and even more preferably 120 ℃ or higher. On the other hand, if the Tg of the adhesive layer is too high, the bendability of the polarizing film is reduced, and therefore, the Tg of the adhesive layer is preferably 300 ℃ or less, more preferably 240 ℃ or less, and further preferably 180 ℃ or less. Tg < glass transition temperature > was measured under the following measurement conditions using a dynamic viscoelasticity measuring apparatus RSAIII manufactured by TAInstructions.
Sample size: 10mm wide and 30mm long,
The distance between the clamps is 20mm,
In the measurement mode: stretching and frequency: 1Hz, temperature rise rate: the dynamic viscoelasticity was measured at 5 ℃ per minute, and the peak top temperature of tan. delta. was used as Tg.
In addition, the adhesive composition preferably has a storage modulus of a cured product layer formed from the adhesive composition, particularly an adhesive layer, of 1.0 × 10 at 25 ℃7Pa or more, more preferably 1.0X 108Pa or above. The storage modulus of the adhesive layer is preferably 1.0X 103Pa～1.0×106Pa. The storage modulus of the adhesive layer affects the polarizer cracks when a heating cycle is applied to the polarizing film (e.g., from-40 ℃ to-80 ℃), and when the storage modulus is low, such a problem that the polarizer cracks easily occurs. The temperature region having a high storage modulus is more preferably 80 ℃ or less, most preferably 90 ℃ or less. Storage modulus and Tg<Glass transition temperature>The measurement was also carried out under the same measurement conditions using a TA Instruments dynamic viscoelasticity measuring apparatus RSAIII. The dynamic viscoelasticity was measured, and the value of the storage modulus (E') was used.
Since the adhesive composition of the present invention contains a curable component, when the adhesive composition is cured, curing shrinkage usually occurs. The cure shrinkage rate is an index indicating the rate of cure shrinkage when the adhesive layer is formed from the resin composition. When the curing shrinkage of the adhesive layer is large, it is preferable to suppress the occurrence of interfacial strain and adhesion failure when the adhesive composition is cured to form the adhesive layer. From the above viewpoint, the cure shrinkage of a cured product obtained by curing the resin composition of the present invention is preferably 10% or less. The cure shrinkage is preferably small, and the cure shrinkage is preferably 8% or less, and more preferably 5% or less. The cure shrinkage rate is measured by the method described in japanese patent application laid-open No. 2013-104869, and more specifically, by the method described in the examples using the cure shrinkage sensor manufactured by SENTEC corporation.
In addition, from the viewpoint of safety, it is preferable to use a material having low skin irritation as the curable component in the adhesive composition used in the present invention. Skin irritation can be judged by an index called p.i.i.i. P.i.i. is widely used as an index indicating the degree of skin damage, and is measured by the Draize method. The measurement value in the range of 0 to 8 indicates that the smaller the value, the lower the irritation, but the larger the error of the measurement value, and therefore, it can be used as a reference value. The p.i.i.i. is preferably 4 or less, more preferably 3 or less, and most preferably 2 or less.
< optical film >
The adhesive composition of the present invention can be suitably used for optical film applications, particularly for polarizing films having at least a polyvinyl alcohol polarizer. Hereinafter, a polarizing film will be described as an example of an optical film.
< polarizing film >
The polarizing film of the present invention is obtained by laminating a transparent protective film on at least one surface of a polarizer via an adhesive layer obtained by curing an adhesive composition for a polarizing film. For example, a transparent protective film may be laminated on one surface of the polyvinyl alcohol polarizer via a cured product layer of the adhesive composition for a polarizing film, or a transparent protective film may be laminated on both surfaces of the polyvinyl alcohol polarizer.
Further, the polarizing film of the present invention may be provided with an adhesive layer. The pressure-sensitive adhesive layer may be laminated at any position, for example, the cured product layer may be laminated on the polyvinyl alcohol polarizer and the pressure-sensitive adhesive layer may be formed thereon, or the cured product layer may be laminated on one surface of the polyvinyl alcohol polarizer and the pressure-sensitive adhesive layer may be laminated on the other surface. Alternatively, an adhesive layer may be laminated on the protective film side of the polarizing film composed of the polarizer/the cured product layer/the protective film. In this way, the pressure-sensitive adhesive layer can be laminated at an arbitrary position of the polarizing film.
The thickness of the polarizing film obtained by laminating the polyvinyl alcohol polarizer, the cured product layer of the composition of the present invention, the transparent protective film, and the adhesive layer is preferably 150 μm or less, and more preferably 100 μm or less. If the thickness of the polarizing film is too large, dimensional change under high temperature and high humidity becomes large, and display unevenness occurs, which is not preferable.
The thickness of the cured product layer formed by the adhesive composition, particularly the adhesive layer, is preferably 0.2 to 3 μm. When the thickness of the cured product layer is too thin, the cohesive force of the cured product layer is insufficient, and the peeling force is reduced, which is not preferable. If the cured product layer is too thick, peeling is likely to occur when stress is applied to the cross section of the polarizing film, and peeling failure due to impact occurs, which is not preferable. The thickness of the adhesive layer is more preferably 0.3 to 2 μm, and most preferably 0.4 to 1.5 μm.
When the thickness of the adhesive layer is d (μm) and the content of the bubble suppressing agent contained in the adhesive layer is y (wt%), the following formula (1) is satisfied, and therefore, the laminated bubble suppressing effect and the adhesion improving effect are both satisfied, which is preferable.
0.1－0.02d≤y≤0.6－0.08d (1)
When y is less than 0.1 to 0.02d, the effect of improving the adhesiveness of the adhesive layer is good, but the number of lamination blisters tends to increase, and when y is more than 0.6 to 0.08d, the effect of suppressing the lamination blisters of the adhesive layer tends to be good, but the effect of improving the adhesiveness tends to be poor. In the above formula (1), the thickness d (. mu.m) of the adhesive layer is preferably 0.2. ltoreq. d.ltoreq.3, more preferably 0.3. ltoreq. d.ltoreq.2, and still more preferably 0.4. ltoreq. d.ltoreq.1.5.
The polarizer is not particularly limited, and various polarizers can be used. Examples of polarizers include: a film obtained by uniaxially stretching a hydrophilic polymer film such as a polyvinyl alcohol film, a partially formalized polyvinyl alcohol film, or an ethylene-vinyl acetate copolymer partially saponified film, a polyene-based alignment film such as a dehydrated polyvinyl alcohol film or a desalted polyvinyl chloride film, and the like, to which a dichroic material such as iodine or a dichroic dye is adsorbed. Among these, a polarizer made of a dichroic material such as a polyvinyl alcohol film and iodine is preferable. The thickness of the polarizers is preferably 2 to 30 μm, more preferably 4 to 20 μm, and most preferably 5 to 15 μm. When the thickness of the polarizer is small, the optical durability is reduced, which is not preferable. When the thickness of the polarizer is large, dimensional change under high temperature and high humidity becomes large, and a defect of display unevenness occurs, which is not preferable.
The polarizer obtained by uniaxially stretching a polyvinyl alcohol film dyed with iodine can be produced, for example, by dyeing polyvinyl alcohol by immersing it in an aqueous iodine solution and stretching it to 3 to 7 times the original length. The substrate may be immersed in an aqueous solution containing potassium iodide or the like containing boric acid as necessary. Further, the polyvinyl alcohol film may be immersed in water and washed with water before dyeing, if necessary. By washing the polyvinyl alcohol film with water, stains and an anti-blocking agent on the surface of the polyvinyl alcohol film can be washed off, and the polyvinyl alcohol film can be swollen to prevent unevenness such as uneven dyeing. The stretching may be performed after the dyeing with iodine, or may be performed while dyeing, or may be performed after the stretching with iodine. Stretching may be carried out in an aqueous solution of boric acid, potassium iodide, or the like, or in a water bath.
In addition, the adhesive composition used in the present invention can exhibit its effect (satisfying optical durability in a severe environment under high temperature and high humidity) remarkably when a thin polarizer having a thickness of 10 μm or less is used as the polarizer. The polarizer having a thickness of 10 μm or less has a relatively large influence of moisture as compared with a polarizer having a thickness of more than 10 μm, and thus has insufficient optical durability in an environment of high temperature and high humidity, and tends to cause an increase in transmittance and a decrease in polarization degree. That is, when the polarizer of 10 μm or less is laminated with the adhesive layer having a volume water absorption of 10 wt% or less according to the present invention, the migration of water to the polarizer can be suppressed in a severe environment under high temperature and high humidity, and thus, deterioration of optical durability such as an increase in transmittance and a decrease in polarization degree of the polarizing film can be remarkably suppressed. From the viewpoint of thinning, the thickness of the polarizer is preferably 1 to 7 μm. Such a thin polarizer is preferable because it has a small variation in thickness, excellent visibility, and a small dimensional change, and further, it can be thinned as the thickness of the polarizing film.
Typical examples of the thin polarizer include thin polarizing films described in Japanese patent application laid-open Nos. 51-069644, 2000-338329, WO2010/100917, and PCT/JP2010/001460, and Japanese patent application publication No. 2010-269002 and No. 2010-263692. These thin polarizing films can be obtained by a production method including a step of stretching a polyvinyl alcohol resin (hereinafter, also referred to as PVA) layer and a stretching resin base material in a state of a laminate, and a step of dyeing. In this production method, even if the PVA based resin layer is thin, it can be stretched without causing troubles such as breakage due to stretching, because it is supported by the resin base material for stretching.
As the thin polarizing film, in a manufacturing method including a step of stretching in a state of a laminate and a step of dyeing, from the viewpoint of being capable of stretching at a high magnification to improve polarizing performance, thin polarizers obtained by a manufacturing method including a step of stretching in an aqueous boric acid solution as described in WO2010/100917 pamphlet, PCT/JP2010/001460 pamphlet, japanese patent application 2010-269002 pamphlet, and japanese patent application 2010-263692 pamphlet are preferable, and in particular, thin polarizers obtained by a manufacturing method including a step of stretching in an auxiliary gas atmosphere before stretching in an aqueous boric acid solution as described in japanese patent application 2010-269002 pamphlet and japanese patent application 2010-263692 pamphlet are preferable.
The transparent protective film is preferably a material having excellent transparency, mechanical strength, thermal stability, moisture barrier properties, isotropy, and the like. Examples thereof include: polyester polymers such AS polyethylene terephthalate and polyethylene naphthalate, cellulose polymers such AS cellulose diacetate and cellulose triacetate, acrylic polymers such AS polymethyl methacrylate, styrene polymers such AS polystyrene and acrylonitrile-styrene copolymer (AS resin), and polycarbonate polymers. Examples of the polymer forming the transparent protective film include: examples of the polymer include polyolefin polymers such as polyethylene, polypropylene, cyclic polyolefins having a norbornene structure, and ethylene-propylene copolymers, amide polymers such as vinyl chloride polymers, nylon and aromatic polyamides, imide polymers, sulfone polymers, polyethersulfone polymers, polyetheretherketone polymers, polyphenylene sulfide polymers, vinyl alcohol polymers, vinylidene chloride polymers, vinyl butyral polymers, aromatic ester polymers, polyoxymethylene polymers, epoxy polymers, and blends of the above polymers. The transparent protective film may contain 1 or more kinds of any suitable additives. Examples of the additives include ultraviolet absorbers, antioxidants, lubricants, plasticizers, mold release agents, coloring inhibitors, flame retardants, nucleating agents, antistatic agents, pigments, and colorants. The content of the thermoplastic resin in the transparent protective film is preferably 50 to 100% by weight, more preferably 50 to 99% by weight, even more preferably 60 to 98% by weight, and particularly preferably 70 to 97% by weight. When the content of the thermoplastic resin in the transparent protective film is 50 wt% or less, high transparency inherent in the thermoplastic resin may not be sufficiently exhibited.
The transparent protective film preferably has a Tg (glass transition temperature) of 115 ℃ or higher, more preferably 120 ℃ or higher, still more preferably 125 ℃ or higher, and particularly preferably 130 ℃ or higher. When the Tg is 115 ℃ or higher, the polarizing film can have excellent durability. The upper limit of Tg of the transparent protective film is not particularly limited, and is preferably 170 ℃ or lower from the viewpoint of moldability and the like.
The polarizer and the transparent protective film may be subjected to a surface modification treatment before the adhesive composition is laminated. In particular, it is preferable that the surface of the polarizer is subjected to a surface modification treatment before the adhesive composition is applied or bonded. Examples of the surface modification treatment include corona treatment, plasma treatment, and ITRO treatment, and corona treatment is particularly preferable. By performing the corona treatment, a polar functional group such as a carbonyl group or an amino group is formed on the surface of the polarizer, and the adhesion to the curable resin layer is improved. Further, foreign matter on the surface is removed by the ashing effect, and unevenness on the surface is reduced, whereby a polarizing film having excellent appearance characteristics can be produced.
When the surface modification treatment is performed on the polarizer, the surface modification treatment is preferably performed so that the surface roughness (Ra) of the surface of the polarizer is 0.6nm or more. The surface roughness (Ra) is preferably 0.8nm or more, and more preferably 1nm or more. By setting the surface roughness (Ra) to 0.6nm or more, the polarizer can be favorably transported even when the surface of the polarizer is brought into contact with the guide roller in the polarizing film manufacturing process. Since the hot water resistance is deteriorated when the surface roughness (Ra) is excessively large, the surface roughness (Ra) is preferably 10nm or less, and more preferably 5nm or less.
The surface roughness (Ra) is measured as a parameter in which the surface roughness is expressed by an arithmetic average roughness (average value of surface irregularities). The surface roughness (Ra) was measured by Tapping mode using an Atomic Force Microscope (AFM) nanoscope iv manufactured by Veeco Instruments. Cantilevers are used, for example, with a metrological probe: tap300(RTESP type), the measurement range is 1 μm square.
The polarizing film of the present invention can be produced by a production method comprising:
a coating step of coating an adhesive composition on at least one surface of the polarizer and the transparent protective film;
a bonding step of bonding the polarizer and the transparent protective film; and
and an adhesive step of irradiating the polarizer side or the transparent protective film side with an active energy ray to cure the adhesive composition to obtain an adhesive layer, and bonding the polarizer and the transparent protective film via the adhesive layer.
The method of applying the adhesive composition for a polarizing film may be appropriately selected depending on the viscosity of the composition and the target thickness, and examples thereof include: reverse coaters, gravure coaters (direct, reverse, or offset), bar reverse coaters, roll coaters, die coaters, wire wound bar coaters, and the like. The viscosity of the adhesive composition used in the present invention is preferably 3 to 100 mPas, more preferably 5 to 50 mPas, and most preferably 10 to 30 mPas. When the viscosity of the curable resin composition is high, surface smoothness after application is insufficient, and appearance defects occur, which is not preferable. The curable resin composition used in the present invention may be applied after the viscosity of the composition is adjusted to a preferable range by heating or cooling.
In general, when 2 films are laminated, the adhesive composition is generally applied to the bonding surface of one film and laminated, but a laminated film having excellent appearance quality can be obtained by applying an adhesive layer to the bonding surface of both films and laminating the films. As a method of coating. Post-measurement of the coating mode is preferred. In the present invention, the "post-measurement coating method" refers to a method of applying an external force to a liquid film to remove an excess liquid and obtain a predetermined coating film thickness. In the method for producing a polarizing film of the present invention, when the external force is applied to the liquid film formed of the adhesive composition, foreign matter such as dust and dirt present on the contact surface is scraped off. Specific examples of the post-measurement coating method include a gravure roll coating method, a forward roll coating method, an air knife coating method, a rod/bar coating method, and the like, but in the present invention, the coating method is preferably a gravure roll coating method using a gravure roll from the viewpoints of accuracy of foreign matter removal, uniformity of coating film thickness, and the like.
The polarizer and the transparent protective film can be bonded to each other by the adhesive composition applied as described above. The polarizer and the transparent protective film may be bonded to each other by a roll laminator or the like. The method of laminating the protective films on both surfaces of the polarizer may be selected from a method of bonding a polarizer and 1 protective film and then further bonding another protective film 1, and a method of simultaneously bonding a polarizer and 2 protective films. The inclusion of bubbles generated during the bonding is preferably reduced significantly by the former method, i.e., the method of bonding a polarizer to 1 protective film and then further bonding another 1 protective film.
The active energy rays used in the curing step can be broadly classified into electron beam curing, ultraviolet curing, and visible light curing. In the present invention, the active energy ray having a wavelength range of 10nm to 380nm is referred to as ultraviolet ray, and the active energy ray having a wavelength range of 380nm to 800nm is referred to as visible ray. In the production of the polarizing film of the present invention, it is particularly preferable to use visible light of 380nm to 450 nm.
In the polarizing film of the present invention, the adhesive composition for a polarizing film is directly applied to the polarizer and/or the transparent protective film, and after the polarizer and the transparent protective film are bonded to each other, the adhesive composition is cured by irradiation with active energy rays (e.g., electron beams, ultraviolet rays, visible light, etc.) to form an adhesive layer. The irradiation direction of the active energy rays (electron beam, ultraviolet ray, visible light, etc.) may be any appropriate direction. Irradiation is preferably from the transparent protective film side. If the irradiation is performed from the polarizer side, the polarizer may be deteriorated by active energy rays (e.g., electron beams, ultraviolet rays, visible light, etc.).
In the electron beam curing, any suitable conditions may be employed as long as the irradiation conditions of the electron beam are such that the adhesive composition for a polarizing film can be cured. For example, the acceleration voltage for electron beam irradiation is preferably 5kV to 300kV, and more preferably 10kV to 250 kV. If the acceleration voltage is less than 5kV, the electron beam may not reach the adhesive composition for polarizing film and the curing may be insufficient, and if the acceleration voltage is more than 300kV, the penetration force through the sample may be too strong and the transparent protective film or polarizer may be damaged. The dose of the radiation is 5 to 100kGy, and more preferably 10 to 75 kGy. When the irradiation dose is less than 5kGy, the adhesive composition for polarizing films is insufficiently cured, and when it exceeds 100kGy, the adhesive composition for polarizing films may damage the transparent protective film and polarizer, resulting in a decrease in mechanical strength and yellowing, and thus, a predetermined optical characteristic may not be obtained.
The electron beam irradiation is usually carried out in an inert gas, and may be carried out in an atmosphere with a small amount of oxygen introduced as required. Oxygen is introduced as appropriate depending on the material of the transparent protective film, and the surface of the transparent protective film which is in contact with the first electron beam is in contact with the oxygen, whereby oxygen inhibition occurs, damage to the transparent protective film can be prevented, and only the adhesive can be efficiently irradiated with an electron beam.
In the method for producing a polarizing film of the present invention, it is preferable to use, as the active energy ray, an active energy ray containing visible light having a wavelength range of 380nm to 450nm, particularly an active energy ray having the largest dose of irradiation of visible light having a wavelength range of 380nm to 450 nm. In the case of using a transparent protective film (ultraviolet-opaque transparent protective film) having ultraviolet absorptivity, the ultraviolet-curable or visible-light-curable composition absorbs light having a wavelength shorter than about 380nm, and therefore, light having a wavelength shorter than 380nm does not reach the adhesive composition and does not contribute to the polymerization reaction. Further, light having a wavelength shorter than 380nm absorbed by the transparent protective film is converted into heat, and the transparent protective film itself generates heat, which causes defects such as curling and wrinkling of the polarizing film. Therefore, in the present invention, when ultraviolet-curing or visible light-curing is employed, it is preferable to use a device that does not emit light having a wavelength shorter than 380nm as the active energy ray generating device, and more specifically, the ratio of the cumulative illuminance in the wavelength range of 380 to 440nm to the cumulative illuminance in the wavelength range of 250 to 370nm is preferably 100:0 to 100:50, and more preferably 100:0 to 100: 40. As the active energy ray of the present invention, a metal halide lamp in which gallium is sealed, and an LED light source which emits light in a wavelength range of 380 to 440nm are preferable. Alternatively, a light source containing ultraviolet rays and visible light such as a low-pressure mercury lamp, a medium-pressure mercury lamp, a high-pressure mercury lamp, an ultrahigh-pressure mercury lamp, an incandescent lamp, a xenon lamp, a halogen lamp, a carbon arc lamp, a metal halide lamp, a fluorescent lamp, a tungsten lamp, a gallium lamp, an excimer laser, or sunlight may be used, or ultraviolet rays having a wavelength shorter than 380nm may be blocked by a band-pass filter and used. In order to improve the adhesion performance of the adhesive layer between the polarizer and the transparent protective film and to prevent curling of the polarizing film, it is preferable to use a metal halide lamp in which gallium is sealed, and to use an active energy ray having a wavelength of 405nm obtained by using a band-pass filter capable of blocking light having a wavelength shorter than 380nm or an active energy ray having a wavelength of 405nm obtained by using an LED light source.
The adhesive composition for a polarizing film of the present invention is particularly suitable for forming an adhesive layer in which a polarizer and a transparent protective film having a light transmittance of less than 5% at a wavelength of 365nm are adhered to each other. Here, the adhesive composition for a polarizing film of the present invention contains the photopolymerization initiator of the general formula (2) described above, and can be cured to form an adhesive layer by irradiating ultraviolet rays through a transparent protective film having UV absorbability. Thus, even in a polarizing film in which transparent protective films having UV absorbing ability are laminated on both surfaces of a polarizer, the adhesive layer can be cured. Of course, the adhesive layer may be cured even in a polarizing film in which a transparent protective film having no UV absorbing ability is laminated. The transparent protective film having UV absorption ability means a transparent protective film having a transmittance of light of 380nm of less than 10%.
Examples of a method for imparting UV absorption ability to the transparent protective film include a method in which an ultraviolet absorber is contained in the transparent protective film, and a method in which a surface treatment layer containing an ultraviolet absorber is laminated on the surface of the transparent protective film.
Specific examples of the ultraviolet absorber include: conventionally known hydroxybenzophenone-based compounds, benzotriazole-based compounds, salicylate-based compounds, benzophenone-based compounds, cyanoacrylate-based compounds, nickel complex salt-based compounds, s-triazine-based compounds, and the like.
In the ultraviolet-curable or visible-light-curable adhesive composition, the adhesive composition for a polarizing film is preferably heated before irradiation with ultraviolet light or visible light (heating before irradiation), and in this case, the heating is preferably to 40 ℃ or higher, more preferably to 50 ℃ or higher. In addition, the adhesive composition for a polarizing film is also preferably heated after irradiation with ultraviolet rays or visible light (heating after irradiation), and in this case, it is preferably heated to 40 ℃ or higher, more preferably heated to 50 ℃ or higher.
In the case of producing the polarizing film of the present invention by a continuous line, the line speed depends on the curing time of the adhesive composition, but is preferably 5 to 100m/min, more preferably 10 to 50m/min, and still more preferably 20 to 30 m/min. When the linear velocity is too low, productivity is insufficient, or damage to the transparent protective film is too large, and a polarizing film which can withstand a durability test or the like cannot be produced. When the linear velocity is too high, the adhesive composition may not be sufficiently cured, and the desired adhesiveness may not be obtained.
The polarizing film of the present invention can be used in practice as an optical film laminated with other optical layers. The optical layer is not particularly limited, and optical layers that are used for forming liquid crystal display devices and the like may be used, for example, 1 or 2 or more layers of reflective plates, semi-transmissive plates, retardation plates (including 1/2 wave plates, 1/4 wave plates, and the like), viewing angle compensation films, and the like. In particular, a reflective polarizing film or a semi-transmissive polarizing film in which a reflective plate or a semi-transmissive reflective plate is further laminated on the polarizing film of the present invention, an elliptical polarizing film or a circular polarizing film in which a retardation plate is further laminated on the polarizing film, a wide-angle polarizing film in which a viewing angle compensation film is further laminated on the polarizing film, or a polarizing film in which a brightness enhancement film is further laminated on the polarizing film is preferable.
The optical film in which the optical layers are laminated on the polarizing film may be formed by sequentially laminating the respective layers in the manufacturing process of the liquid crystal display device, etc., but when the optical film is laminated in advance, there are advantages in that the quality stability, the assembly work, etc. are excellent, and the manufacturing process of the liquid crystal display device, etc. can be improved. The lamination may be performed by an appropriate bonding method such as an adhesive layer. When the polarizing film or the other optical film is bonded, the optical axes thereof may be set at an appropriate arrangement angle depending on the desired retardation characteristics and the like.
An adhesive layer for adhesion to other members such as a liquid crystal cell may be provided to the polarizing film described above or to an optical film in which at least 1 polarizing film is laminated. The pressure-sensitive adhesive for forming the pressure-sensitive adhesive layer is not particularly limited, and for example, a pressure-sensitive adhesive using a polymer such as an acrylic polymer, a silicone polymer, a polyester, a polyurethane, a polyamide, a polyether, a fluorine polymer, or a rubber as a base polymer can be suitably selected and used. In particular, an acrylic pressure-sensitive adhesive which is excellent in optical transparency, exhibits appropriate adhesive properties such as wettability, cohesiveness and adhesiveness, and is excellent in weather resistance, heat resistance and the like is preferably used.
The adhesive layer may be provided on one or both surfaces of the polarizing film or the optical film as a stacked layer of layers of different compositions, kinds, or the like. In the case of providing both surfaces, adhesive layers having different compositions, kinds, thicknesses, and the like may be provided on the front and back surfaces of the polarizing film and the optical film. The thickness of the adhesive layer is suitably determined depending on the purpose of use, adhesion and the like, and is usually 1 to 100. mu.m, preferably 5 to 30 μm, and particularly preferably 10 to 20 μm.
The exposed surface of the adhesive layer is covered with a separator temporarily attached to prevent contamination and the like until the adhesive layer is actually used. This prevents contact with the adhesive layer in a normal processing state. As the separator, in addition to the above thickness conditions, a conventionally suitable separator such as a separator obtained by coating a suitable sheet material such as a plastic film, a rubber sheet, paper, cloth, a nonwoven fabric, a net, a foam sheet, a metal foil, or a laminate thereof with a suitable release agent such as silicone, long-chain alkyl, fluorine, or molybdenum sulfide, as necessary, can be used.
The polarizing film or optical film of the present invention can be preferably used for formation of various devices such as a liquid crystal display device. The liquid crystal display device can be formed in a conventional manner. That is, the liquid crystal display device can be generally formed by appropriately assembling a liquid crystal cell, a polarizing film or an optical film, and components such as an illumination system used as needed, and introducing them into a driver circuit or the like. As the liquid crystal cell, any type of liquid crystal cell such as TN type, STN type, pi type, or the like can be used.
A suitable liquid crystal display device such as a liquid crystal display device in which a polarizing film or an optical film is disposed on one side or both sides of a liquid crystal cell, a liquid crystal display device using a backlight or a reflector in an illumination system, or the like can be formed. In this case, the polarizing film or the optical film of the present invention may be disposed on one side or both sides of the liquid crystal cell. In the case where the polarizing film or the optical film is provided on both sides, they may be the same material or different materials. Further, in forming a liquid crystal display device, appropriate members such as a diffusion plate, an antiglare layer, an antireflection film, a protective plate, a prism array, a lens array sheet, a light diffusion plate, and a backlight may be disposed in appropriate positions in 1 layer or 2 layers or more.
Examples
Examples of the present invention are described below, but the embodiments of the present invention are not limited thereto.
(preparation of curable resin composition)
Adhesive composition A was obtained by stirring 54.5 wt% of 1, 9-nonanediol diacrylate as an active energy ray-curable component, 10 wt% of hydroxyethyl acrylamide, 30 wt% of acryloyl morpholine, "BYK-UV 3570" manufactured by BYK corporation as a bubble inhibitor having a reactive group, 3 wt% of IRGACURE907 as a polymerization initiator, and 2 wt% of KAYACURE DETX-S for 3 hours.
< preparation of polarizer >
A polyvinyl alcohol film having a thickness of 45 μm and an average polymerization degree of 2400 and a saponification degree of 99.9 mol% was immersed in warm water at 30 ℃ for 60 seconds to swell the film. Then, the film was immersed in an aqueous solution of iodine/potassium iodide (weight ratio: 0.5/8) having a concentration of 0.3%, and the film was dyed while being stretched 3.5 times. Then, the resultant was stretched in an aqueous solution of boric acid ester at 65 ℃ so that the total stretching ratio became 6 times. After the stretching, the film was dried in an oven at 40 ℃ for 3 minutes to obtain a polyvinyl alcohol polarizer X (thickness: 18 μm).
< production of thin polarizer >
In order to produce a thin polarizer, a laminate having a 24 μm-thick PVA layer formed on an amorphous PET substrate was first subjected to auxiliary stretching at a stretching temperature of 130 ℃ in a gas atmosphere to form a stretched laminate, the stretched laminate was then dyed to form a colored laminate, and the colored laminate was further subjected to underwater stretching in boric acid at a stretching temperature of 65 ℃ to integrally stretch the amorphous PET substrate so that the total stretching magnification became 5.94 times, thereby forming an optical film laminate including a 10 μm-thick PVA layer. By such 2-step stretching, an optical film laminate (total thickness 40 μm) including a PVA layer having a thickness of 5 μm constituting a thin polarizer Y in which PVA molecules of the PVA layer formed on the amorphous PET substrate are highly oriented and iodine adsorbed by dyeing is highly oriented in one direction in the form of a polyiodide ion complex can be formed.
< transparent protective film >
(i) Acryl; 100 parts by weight of the imidized MS resin described in production example 1 of JP-A2010-284840 and 0.62 parts by weight of the s-triazine ultraviolet absorber (product name: T-712, manufactured by Adeca) were mixed together by means of a twin-screw kneader at 220 ℃ to prepare resin pellets. The obtained resin pellets were dried at 100.5kPa and 100 ℃ for 12 hours, extruded from a T-die by a single-screw extruder at a die temperature of 270 ℃ and molded into a film shape (thickness: 160 μm). The film was further stretched in the direction of transport at 150 ℃ in an atmosphere (thickness 80 μm), then coated with an easy-adhesive agent comprising an aqueous urethane resin, and then stretched in the direction orthogonal to the direction of transport of the film at 150 ℃ in an atmosphere to give a film having a thickness of 40 μm (moisture permeability 58 g/m)224h) transparent acrylic film (Acryl).
(ii) COP; a cyclic polyolefin film (manufactured by ZEON Co., Ltd.) having a thickness of 52 μm was used.
(iii) TAC; a cellulose triacetate film (manufactured by Fuji film Co., Ltd.) having a thickness of 60 μm was used.
< peeling force >
The polarizing film was cut out to a size of 200mm parallel to the stretching direction of the polarizer and 15mm in the orthogonal direction, and the polarizing film was laminated on a glass plate. Then, a cut was made between the transparent protective film (1 st protective film or 2 nd protective film) and the polarizer by a cutter, and the protective film and the polarizer were peeled off at a peeling speed of 300mm/min in a 90-degree direction by Tensilon, and the peel strength (N/15mm) was measured.
< air bubble before lamination >
The sample immediately after the adhesive was applied was sampled, and the number of bubbles was counted by observing both surfaces with an optical microscope. The number of bubbles was counted in the range of 5cm × 5cm, and the total number of bubbles on the coated surface was confirmed.
< laminated bubble >
The number of bubbles was counted by observing both surfaces of the polarizing film with an optical microscope. The number of bubbles was counted in the range of 5cm × 5cm, and the total number of bubbles on both sides was confirmed.
< surface tension >
The measurement was performed by the hanging Drop method using Drop Master (Kanghe interface science, Ltd.).
Example 1
On each of the No. 1 protective film (Acryl) and the No. 2 protective film (COP), an adhesive composition A was applied using an MCD coater (manufactured by Fuji mechanical Co., Ltd.) (cell shape: number of honeycomb and gravure rolls: 1000, rotation speed: 180%/counter roll) so that the thickness became 0.5. mu.m, and the adhesive composition A was bonded to both surfaces of the polarizer X by a roll machine. Then, the above-mentioned visible light was irradiated from both sides of the transparent protective film (both sides) to be bonded with an active energy ray irradiation apparatus to cure the curable adhesive, and then the cured adhesive was dried with hot air at 70 ℃ for 3 minutes to obtain a polarizing film having transparent protective films on both sides of the polarizer. The lamination was carried out at a lamination line speed of 25 m/min.
Example 2
For the adhesive composition a used in example 1, an adhesive composition B having the same composition was used except that the bubble suppressing agent having a reactive group was changed to 0.5 wt% of "BYK-UV 3505" manufactured by BYK corporation.
Comparative example 1
Evaluation was performed in the same manner as in example 1 except that the composition of the adhesive composition a was changed to an adhesive composition C having the same composition except that "BYK-UV 3570" manufactured by BYK corporation was removed.
Comparative example 2
An adhesive composition D having the same composition as that used in example 1, except that the reactive group-containing bubble suppressant was changed to 0.5 wt% of "401 LS Additive" which is a polyether-modified silicone-based bubble suppressant having no reactive group, was used as the adhesive composition a.
Example 3
Evaluation was performed in the same manner as in example 1 except that TAC was used as the 1 st protective film.
Comparative example 3
Evaluation was performed in the same manner as in example 3, except that the adhesive composition C was used instead of the adhesive composition a.
Example 4 and comparative example 4
Evaluation was performed in the same manner as in example 1 except that the adhesive compositions described in table 1 were used instead of the adhesive composition a, the thin polarizer Y was used instead of the polarizer X, and a polarizing film produced by the following method was used.
The optical film laminate including the thin polarizer Y was subjected to a 5-minute drying at 50 ℃ after the 1 st protective film was bonded to the surface of the thin polarizer Y while applying each adhesive composition described in table 1. Next, the amorphous PET substrate was peeled off, and the adhesive compositions described in table 1 were applied to the peeled surface, and after a 2 nd protective film was laminated, the film was cured by ultraviolet light, thereby producing a polarizing film using the thin polarizer Y.
Example 5 and comparative example 5
Evaluation was performed in the same manner as in example 1 except that the adhesive compositions described in table 1 were used instead of the adhesive composition a.
Figure BDA0003508333730000401
In table 1, the active energy ray-curable components were:
1, 9-nonanediol diacrylate; Light-Acrylate 1,9ND-A manufactured by Kyoeisha chemical Co., Ltd,
Hydroxyethyl acrylamide; "HEAA" manufactured by XINGZHEN corporation,
Acryloyl morpholine; "ACMO" manufactured by Xinghai corporation,
Hydroxypivalic acid neopentyl glycol acrylic acid adduct; Light-Acrylate HPP-A manufactured by KyoeishｃA chemical Co., Ltd "
2-hydroxy-3-phenoxypropyl acrylate; "M5700" manufactured by Toyo Seisakusho Kabushiki Kaisha "
Bisphenol a type epoxy resin; trade name "jER-828", manufactured by Nippon epoxy resin Co., Ltd,
3-ethyl-3-phenoxymethyloxetane; the product name is "ARON OXETANE OXT-211", manufactured by TOYA SYNTHETIC CO., LTD.
Bubble inhibitors having reactive groups are:
silicone bubble inhibitors (containing urethane bonds and isocyanurate ring structures) as modified polydimethylsiloxanes having acryloyl functional groups; BYK-UV3505 manufactured by BYK,
Silicone bubble inhibitors (containing urethane bonds and isocyanurate ring structures) as polyester-modified polydimethylsiloxanes having acryloyl functional groups; BYK-UV3570, BYK.
Bubble inhibitors without reactive groups are:
polyether modified silicone bubble inhibitor; "401 LS Additive" manufactured by Dow Corning corporation.
The polymerization initiator is:
IRGACURE 907; manufactured by BASF corporation,
KAYACURE DETX-S; manufactured by Nippon Chemicals K.K.),
Propylene carbonate solution containing triarylsulfonium hexafluorophosphate as main component and 50% of effective component; the trade name is "UVI-6992", manufactured by Dow Chemical Co.
Examples 6 to 18
Evaluation was performed in the same manner as in example 2, except that the content y (wt%) of the bubble inhibitor contained in the adhesive layer was changed to the content shown in table 2 and the thickness d (μm) of the adhesive layer was changed to the thickness shown in table 2 with respect to the composition B used in example 2.
Figure BDA0003508333730000421

Claims (13)

1. An adhesive composition for a polarizing film, which contains an active energy ray-curable component and a bubble inhibitor having a reactive group.
2. The adhesive composition for a polarizing film according to claim 1, wherein the bubble inhibitor is a silicone-based bubble inhibitor having a reactive group.
3. The adhesive composition for a polarizing film according to claim 1 or 2, wherein the bubble inhibitor has a (meth) acryloyl group as a reactive group.
4. The adhesive composition for a polarizing film according to any one of claims 1 to 3, wherein the bubble inhibitor has a urethane bond.
5. The adhesive composition for a polarizing film according to any one of claims 1 to 4, wherein the bubble inhibitor has an isocyanurate ring structure.
6. The adhesive composition for a polarizing film according to any one of claims 1 to 5, wherein the bubble inhibitor is contained in an amount of 0.01 to 0.6% by weight based on 100% by weight of the total amount of the composition.
7. The adhesive composition for a polarizing film according to any one of claims 1 to 6, which has a surface tension of 30mN/m or less before curing.
8. The adhesive composition for a polarizing film according to any one of claims 1 to 7, wherein the active energy ray-curable component contains at least a radical polymerizable compound.
9. A polarizing film comprising a polarizer and a transparent protective film laminated on at least one surface of the polarizer via an adhesive layer obtained by curing the adhesive composition for polarizing films according to any one of claims 1 to 8.
10. The polarizing film according to claim 9, wherein the adhesive layer has a thickness of 0.2 to 3 μm.
11. The polarizing film according to claim 9 or 10, wherein the following formula (1) is satisfied where d (μm) is the thickness of the adhesive layer and y (wt%) is the content of the bubble inhibitor contained in the adhesive layer,
0.1－0.02d≤y≤0.6－0.08d (1)。
12. an optical film comprising at least 1 polarizing film according to any one of claims 9 to 11 laminated thereon.
13. An image display device using the polarizing film according to any one of claims 9 to 11 or the optical film according to claim 12.
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