TWI874520B - Optical laminate and image display device - Google Patents

Abstract

An objective of the present invention is to provide a novel optical laminate in which color loss is suppressed at an end portion of a polarizer under high temperature and high humidity.

An optical laminate according to the present invention has a polarizer, a light-selective absorbing pressure-sensitive adhesive layer, and an intermediate layer laminated between and in contact with the polarizer and the light-absorbing pressure-sensitive adhesive layer. The intermediate layer has only one or a plurality of layers selected from the group consisting of a liquid crystal cured layer, an oriented layer, and a bonded layer. The polarizer has iodine adsorbed and oriented therein, and contains boron with an content ratio of 5.0% by mass or less. The light-selective absorbing pressure-sensitive adhesive layer contains a light-selective absorbing agent, and has an absorbance of 0.1 or more and 2.3 or less at a wavelength of 410 nm.

Description

Optical multilayer body and image display device

The present invention relates to an optical multilayer body and an image display device.

The polarizing plate formed by laminating a protective film on one or both sides of the polarizer is an optical component. The optical component is widely used in image display devices such as liquid crystal display devices or organic electroluminescent (organic EL) display devices, such as portable devices and televisions. In recent years, it has been widely used in various portable devices such as mobile phones, smart phones, and tablet terminals.

Polarizing plates are mostly used by being attached to image display elements (liquid crystal units or organic EL display elements, etc.) via an adhesive (pressure-sensitive adhesive, also known as a pressure-sensitive adhesive) layer (for example, Japanese Patent Publication No. 2010-229321 (Patent Document 1)). Therefore, polarizing plates are sometimes circulated in the market in the form of polarizing plates with an adhesive layer pre-set on one side.

In addition, portable devices are often used in harsh environments of high temperature and high humidity, and high durability is required for polarizers. Japanese Patent Publication No. 2013-105036 (Patent Document 2) states that by increasing the boric acid content in the polarizer and generating a large amount of boric acid crosslinks, the _I3 complex exists with high orientation and high stability, thereby obtaining a polarizer with excellent low-temperature and high-humidity durability that suppresses the generation of blue leakage.

[Prior Art Literature]

[Patent Literature]

Patent document 1: Japanese Patent Publication No. 2010-229321.

Patent document 2: Japanese Patent Publication No. 2013-105036.

Polarizing plates have the problem of easy discoloration at the ends of the polarizer in a high temperature and high humidity environment. This problem is more prominent in a structure where only a single layer of protective film is laminated on the polarizer. Although there is a known method of suppressing the discoloration of polarizers by increasing the boron content in the polarizer, this method has the problem of easy shrinkage due to heating.

The purpose of the present invention is to provide a novel optical multilayer body in which discoloration at the end of the polarizer is suppressed under high temperature and high humidity.

The present invention provides the optical multilayer body and the image display device using the optical multilayer body as exemplified below.

[1] An optical laminate having a polarizer, a light selectively absorbing adhesive layer, and an intermediate layer laminated between the polarizer and the light selectively absorbing adhesive layer and in contact with the polarizer and the light selectively absorbing adhesive layer, wherein:

The aforementioned intermediate layer only has one or more layers selected from the group consisting of a liquid crystal curing layer, an alignment layer, and a bonding layer.

The aforementioned polarizer is iodine-adsorbed and oriented and has a boron content of less than 5.0 mass %.

The aforementioned light selective absorbing adhesive layer contains a light selective absorber and has an absorbance of 0.1 or more and 2.3 or less at a wavelength of 410nm.

[2] The optical laminate as described in [1] further comprises a protective film, wherein the protective film is laminated on the side of the polarizer opposite to the side of the intermediate layer.

[3] The optical multilayer body as described in [1] or [2], wherein the content of the light selective absorber per unit area in the light selective absorber adhesive layer is not less than 0.01 g/ ^m2 and not more than 5 g/ ^m2 .

[4] An optical laminate as described in any one of [1] to [3], wherein the light selective absorbing adhesive layer contains 0.1 to 10 parts by mass of the light selective absorber relative to 100 parts by mass of the total resin component contained in the light selective absorbing adhesive layer.

[5] An optical multilayer as described in any one of [1] to [4], wherein the thickness of the aforementioned light selective absorption adhesive layer is greater than 0.1μm and less than 150μm.

[6] An optical multilayer as described in any one of [1] to [5], wherein the aforementioned light selective absorber is an organic light selective absorber having a molecular weight of not less than 100 and not more than 3000.

[7] An optical multilayer as described in any one of [1] to [6], wherein the intermediate layer has a λ/4 phase difference layer belonging to the liquid crystal curing layer.

[8] An optical layered body as described in any one of [1] to [7], which is an anti-reflection polarizing plate.

[9] An image display device comprises an image display panel and the optical multilayer body described in [8] disposed on the front surface of the image display panel.

[10] An image display device as described in [9], wherein the image display panel is an organic EL display panel.

According to the present invention, an optical laminate in which discoloration at the end of the polarizer is suppressed in a high temperature and high humidity environment, and an image display device containing the optical laminate can be provided.

10: Polarizer

11: Protective film

20: Photoselective absorbent adhesive layer

30: First liquid crystal hardening layer

31: Second liquid crystal hardening layer

32: Second adhesive layer

33: Next is the agent layer

50: End of optical layer

51: Discoloration area

52: Non-fading area

100,101,102: Optical multilayers

300: Middle layer

FIG1 is a schematic cross-sectional view showing an example of the optical multilayer body of the present invention.

FIG2 is a schematic cross-sectional view showing an example of the optical multilayer body of the present invention.

FIG3 is a schematic cross-sectional view showing an example of the optical multilayer body of the present invention.

Figure 4 is a diagram showing an example of an image observed by an optical microscope.

Figure 5 shows an example of data obtained by converting the observed image into 256 levels of black and white.

The following describes the implementation of the present invention with reference to the drawings, but the present invention is not limited to the following implementation. In all the following drawings, the scale is appropriately adjusted to represent each component for easy understanding, and the scale of each component shown in the drawings may not be consistent with the scale of the actual component.

<Optical layered structure>

The optical multilayer of the present invention has a polarizer, a light selective absorption adhesive layer, and an intermediate layer stacked between the polarizer and the light selective absorption adhesive layer and in contact with the polarizer and the light absorption adhesive layer. An example of the layer structure of the optical multilayer of the present invention is shown in Figures 1, 2, and 3.

FIG1 is a schematic cross-sectional view of an example of the optical laminate of the present invention. The optical laminate 100 shown in FIG1 has a protective film 11, a polarizer 10, an intermediate layer 300, and a light selective absorption adhesive layer (hereinafter, also referred to as the "first adhesive layer") 20 in sequence. The intermediate layer 300 has only one layer or a plurality of layers selected from the group consisting of a liquid crystal curing layer, an alignment layer, and a bonding layer.

FIG2 is a schematic cross-sectional view of an example of the optical multilayer of the present invention. The optical multilayer 101 shown in FIG2 has a protective film 11, a polarizer 10, an intermediate layer 300, and a light selective absorption adhesive layer 20 in sequence. The intermediate layer 300 has a second adhesive layer 32, a first liquid crystal curing layer 30, a bonding agent layer 33, and a second liquid crystal curing layer 31 in sequence from the side of the polarizer 10.

FIG3 is a schematic cross-sectional view of an example of the optical laminate of the present invention. The optical laminate 102 shown in FIG3 has a protective film 11, a polarizer 10, an intermediate layer 300, and a light selective absorption adhesive layer 20 in sequence. The intermediate layer 300 is composed of a second adhesive layer 32.

The thickness of the optical laminates 100, 101, and 102 varies depending on the functions required of the optical laminates and the uses of the optical laminates, and is not particularly limited, but may be, for example, 5 μm to 200 μm, 10 μm to 150 μm, or 120 μm or less.

The light selective absorbing adhesive layer contains a light selective absorber. In the optical laminate of the present invention, at least the light selective absorbing adhesive layer has light selective absorbing properties, thereby making the optical laminate as a whole have light selective absorbing properties. Therefore, when the optical laminate of the present invention is used on an image display element, it has the function of protecting the image display element from the influence of ultraviolet rays.

The optical laminate of the present invention may be a structure including a layer having light selective absorption performance in addition to the light selective absorption adhesive layer. The other layers may be, for example, the protective film 11 and the intermediate layer 300. In the present invention, the light selective absorption adhesive layer has light selective absorption performance and is helpful in showing the light selective absorption performance of the optical laminate as a whole, so that the design freedom of the light selective absorption performance in other layers can be improved. For example, in order to improve the light selective absorption performance, the protective film 11 may need to be designed to be thicker, but by making the design freedom of the light selective absorption performance high, it is easier to make the protective film 11 thinner. For example, from the perspective of suppressing discoloration at the end of the polarizer under high temperature and high humidity, the intermediate layer 300 is preferably composed of substantially no light selective absorber, and even if it contains light, its content is preferably 0.5 g/ ^m2 or less. When the intermediate layer 300 has a second adhesive layer, the second adhesive layer is also preferably composed of substantially no light selective absorber, and even if it contains light, its content is preferably 0.5 g/ ^m2 or less.

The inventors of the present invention have found that there is a correlation between the content of the light selective absorber contained in the adhesive layer and the degree of discoloration at the end of the polarizer under high temperature and high humidity. Based on this view, it is believed that the light selective absorber in the light selective absorber adhesive layer is easily transferred to the polarizer side under high temperature and high humidity, and this transfer is one of the main causes of discoloration. The inventors of the present invention have further studied and found that even when the light selective absorber adhesive layer contains a light selective absorber, by adjusting the layering position and absorbance of the light selective absorber adhesive layer, discoloration at the end of the polarizer under high temperature and high humidity can be suppressed, thereby completing the present invention.

[Polarizer]

The polarizer has the following properties: it absorbs linear polarized light with a vibration plane parallel to its absorption axis, and allows linear polarized light with a vibration plane orthogonal to the absorption axis (parallel to the transmission axis) to pass through. The polarizer 10 in the optical multilayer of the present invention is iodine adsorbed and oriented and has a boron content of 5.0 mass % or less.

By making the boron content less than 5.0 mass %, preferably less than 4.5 mass %, shrinkage caused by heating can be suppressed. The boron content is preferably more than 0.5 mass %, and more preferably more than 1 mass %. In the polarizer 10, the lower the boron content, the easier it is to produce discoloration at the end of the polarizer under high temperature and high humidity. It is generally believed that the boron in the polarizer 10 will increase the crosslinking degree of the polarizer 10, which helps to stably maintain iodine in the polarizer 10. Therefore, if the boron content decreases, iodine cannot be stably maintained, and discoloration will occur. In the present invention, even if the boron content of the polarizer 10 is less than 5.0 mass %, discoloration under high temperature and high humidity can still be suppressed.

The polarizer 10 may include a stretched film or stretched layer adsorbing a dichroic dye with anisotropic absorption, a cured product containing a polymerizable liquid crystal compound, and a liquid crystal cured layer of a dichroic dye. A dichroic dye is a dye with different properties in the absorbance in the long axis direction and the absorbance in the short axis direction of the molecule, and iodine is suitable for use as the dye.

(1) A polarizer that is a stretched film or stretched layer that has absorbed a pigment with anisotropic absorption.

Polarizers that are stretched films that adsorb anisotropically absorbing pigments can usually be manufactured through the following steps: a step of uniaxially stretching a polyvinyl alcohol resin film; a step of dyeing the polyvinyl alcohol resin film with a dichroic pigment such as iodine to adsorb the dichroic pigment; a step of treating the polyvinyl alcohol resin film adsorbing the dichroic pigment with a boric acid aqueous solution; and a step of washing with water after the boric acid aqueous solution treatment.

The thickness of the polarizer is usually less than 30μm, preferably less than 15μm, more preferably less than 13μm, even more preferably less than 10μm, and particularly preferably less than 8μm. The thickness of the polarizer is usually more than 2μm, preferably more than 3μm, for example, more than 5μm.

Polyvinyl alcohol resins are obtained by saponifying polyvinyl acetate resins. In addition to polyvinyl acetate, which is a homopolymer of vinyl acetate, polyvinyl acetate resins can also use copolymers of vinyl acetate and other monomers that can be copolymerized with vinyl acetate. Other monomers that can be copolymerized with vinyl acetate include unsaturated carboxylic acid compounds, olefin compounds, vinyl ether compounds, unsaturated sulfonate compounds, and (meth)acrylamide compounds having an ammonium group.

The saponification degree of polyvinyl alcohol resin is usually about 85 mol% to 100 mol%, preferably 98 mol% or more. Polyvinyl alcohol resin can be modified, and polyvinyl formal, polyvinyl acetaldehyde, etc. modified with aldehydes can also be used. The polymerization degree of polyvinyl alcohol resin is usually 1000 to 10000, preferably 1500 to 5000.

The polarizer having a stretched layer adsorbed with a dye having anisotropic absorption can usually be manufactured through the following steps: a step of applying a coating liquid containing the above-mentioned polyvinyl alcohol resin on a substrate film; a step of uniaxially stretching the obtained laminated film; a step of dyeing the polyvinyl alcohol resin layer of the uniaxially stretched laminated film with a dichroic dye such as iodine to adsorb the dichroic dye and form a polarizer; a step of treating the film adsorbed with the dichroic dye with an aqueous boric acid solution; and a step of washing with water after the boric acid aqueous solution treatment. The substrate film used to form the polarizer can also be used as a protective film 11. The substrate film can be peeled off from the polarizer as needed. The material and thickness of the substrate film can be the same as the material and thickness of the protective film 11 described later.

[Protective film]

The protective film 11 can be a coating or film composed of an optically transparent thermoplastic resin, such as: cyclic polyolefin resin; cellulose acetate resin including cellulose triacetate, cellulose diacetate and other resins; polyester resin including polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate and other resins; polycarbonate resin; (meth) acrylic resin; polypropylene resin, or a mixture of one or more of these. The protective film 11 may contain the light selective absorber described below. In addition, the light selective absorber contained in the protective film 11 is retained in the protective film 11, so it is not easily transferred to the polarizer.

A hard coating layer can be formed on the protective film 11. The hard coating layer can be formed on one side or on both sides of the protective film 11. By providing the hard coating layer, a protective film 11 with improved hardness and scratch resistance can be formed. The hard coating layer can be, for example, a hardening layer of an acrylic resin, a silicone resin, a polyester resin, a urethane resin, an amide resin, an epoxy resin, or the like. In order to increase the strength, the hard coating layer can contain an additive. The additive is not limited, and inorganic microparticles, organic microparticles, or a mixture thereof can be cited. The hard coating layer is, for example, a hardening layer of a UV-curing resin. Examples of UV-curable resins include acrylic resins, silicone resins, polyester resins, urethane resins, amide resins, epoxy resins, etc.

The thickness of the protective film is usually 1 to 100 μm, preferably 5 to 80 μm, more preferably 8 to 60 μm, and even more preferably 12 to 45 μm from the perspective of strength or handling.

The resin film of the protective film 11 is bonded to the polarizer 10, for example, via an adhesive layer. The adhesive that forms the adhesive layer may be a water-based adhesive, an active energy ray-curable adhesive, or a thermosetting adhesive, preferably a water-based adhesive or an active energy ray-curable adhesive. The two opposing surfaces to be bonded via the adhesive layer may be subjected to corona treatment, plasma treatment, flame treatment, etc. in advance, and may also have a primer layer, etc.

[Photoselective absorptive adhesive layer]

The adhesive composition is dissolved or dispersed in an organic solvent to form a dilute solution, and the dilute solution is applied to a substrate and dried to form a light selective absorbing adhesive layer 20. The substrate is preferably a plastic film, and specifically, a release film subjected to a release treatment can be cited. The release film can be a film made of a resin such as polyethylene terephthalate, polybutylene terephthalate, polycarbonate, or polyarylate, on one side of which a release treatment such as polysilicone treatment is applied.

The thickness of the light selective absorption adhesive layer is, for example, 0.1 μm to 150 μm. When laminated with an image display panel, it is usually 8 μm to 60 μm, preferably 30 μm to 30 μm, more preferably 25 μm to 20 μm, and particularly preferably 18 μm to 3 μm, preferably, and can be, for example, 10 μm or more. However, from the perspective of further thinning, it is preferably 10 μm or less, and particularly preferably 7 μm or less.

The absorbance of the light selective absorption adhesive layer at a wavelength of 410nm is preferably 0.1 or more and 2.3 or less, and more preferably 0.2 or more and 2.0 or less. The reason is that by making the light selective absorption adhesive layer 20 have such an absorbance, the optical laminate as a whole can exhibit the desired light selective absorption performance, and the optical laminate as a whole can be easily constructed into a thin shape.

In the photoselective absorbent adhesive layer,

The absorbance at a wavelength of 390nm is usually below 5.0, and can be below 4.5. The absorbance at a wavelength of 400nm is usually below 5.0, and can be below 4.5. The absorbance at a wavelength of 420nm is usually below 1.00, preferably below 0.60, more preferably below 0.40, and above 0.00.

The absorbance at a wavelength of 430nm is usually less than 0.20, preferably less than 0.18, more preferably less than 0.10, particularly preferably less than 0.05, and greater than 0.00,

The absorbance at a wavelength of 440nm is usually less than 0.10, preferably less than 0.05 and greater than 0.00.

By making the absorbance at individual wavelengths within the above range, light in the ultraviolet region can be fully absorbed, and light in the visible region can be directly transmitted.

The content of the light selective absorber per unit area of the light selective absorber adhesive layer is preferably 0.01 g/m ² or more and 5 g/m ² or less. By setting it within this range, the discoloration of the polarizer produced under high temperature and high humidity can be suppressed.

In the optical laminate, the light selective absorption adhesive layer 20 can be disposed on the outermost surface, and the optical laminate is constructed in such a way that the optical laminate is attached to the adherend through the light selective absorption adhesive layer 20.

[Adhesive composition]

The adhesive composition contains a resin and a light selective absorber, and preferably further contains a crosslinking agent.

The resin is, for example, a resin having a (meth)acrylic resin, a rubber resin, a urethane resin, an ester resin, a polysilicone resin, a polyvinyl ether resin, or the like as a main component. Among them, a resin having a (meth)acrylic resin (A) as a main component is preferred.

(Photoselective absorber)

Photoselective absorbers selectively absorb light of a specific wavelength, preferably containing a compound with at least one absorption maximum at a wavelength of 360nm to 420nm, and more preferably containing a compound with an absorption maximum at a wavelength of 380nm to 410nm.

The light selective absorber containing a compound having an absorption maximum value near a wavelength of 350 nm (hereinafter sometimes referred to as the light selective absorber (A)) includes organic light selective absorbers such as oxydiphenyl ketone-based light selective absorbers, benzotriazole-based light selective absorbers, salicylate-based light selective absorbers, diphenyl ketone-based light selective absorbers, cyanoacrylate-based light selective absorbers, and triazine-based light selective absorbers. More specifically, examples include 5-chloro-2-(3,5-di-sec-butyl-2-hydroxyphenyl)-2H-benzotriazole, (2-2H-benzotriazole-2-yl)-6-(linear and side chain dodecyl)-4-methylphenol, 2-hydroxy-4-benzyloxydiphenyl ketone, 2,4-benzyloxydiphenyl ketone, etc. These organic photoselective absorbers can be one or two or more. The molecular weight of the organic photoselective absorber is preferably 100 or more and 3000 or less.

As the light selective absorber (A), commercially available products can be used. Examples of the triazine-based light selective absorber include "Kemisorb 102" manufactured by CHEMIPRO KASEI Co., Ltd., "ADK STAB LA46" and "ADK STAB LAF70" manufactured by ADEKA Co., Ltd., and "TINUVIN 109", "TINUVIN 171", "TINUVIN 234", "TINUVIN 326", "TINUVIN 327", "TINUVIN 328", "TINUVIN 928", "TINUVIN 400", "TINUVIN 460", "TINUVIN 405", and "TINUVIN 477" manufactured by BASF JAPAN. Examples of benzotriazole-based photoselective absorbers include "ADK STAB LA31" and "ADK STAB LA36" manufactured by ADEKA Co., Ltd., "Sumisorb 200", "Sumisorb 250", "Sumisorb 300", "Sumisorb 340" and "Sumisorb 350" manufactured by Sumika Chemtex Co., Ltd., "Kemisorb 74", "Kemisorb 79" and "Kemisorb 279" manufactured by CHEMIPRO KASEI Co., Ltd., and "TINUVIN 99-2", "TINUVIN 900" and "TINUVIN 928" manufactured by BASF.

Furthermore, the light selective absorber (A) may be an inorganic light selective absorber. Examples of the inorganic light selective absorber include titanium oxide, zinc oxide, indium oxide, tin oxide, talc, kaolin, calcium carbonate, titanium oxide composite oxides, zinc oxide composite oxides, ITO (tin-doped indium oxide), ATO (antimony-doped tin oxide), etc. Examples of titanium oxide composite oxides include titanium oxide doped with silicon dioxide and aluminum oxide. Such inorganic light selective absorbers may be used alone or in combination of two or more. Furthermore, organic light selective absorbers and inorganic light selective absorbers may be used in combination.

The light selective absorber containing a compound having an absorption maximum value near a wavelength of 405 nm (hereinafter, sometimes referred to as light selective absorber (B)) is preferably a compound satisfying the following formula (5), and more preferably a compound satisfying the following formula (6) at the same time.

ε(405)≧20 (5)

[In formula (5), ε(405) represents the gram absorption coefficient of the compound at a wavelength of 405nm.

The unit of gram absorption coefficient is L/(g‧cm)〕

ε(405)/ε(440)≧20 (6)

[In formula (6), ε(405) represents the gram absorbance coefficient of the compound at a wavelength of 405nm, and ε(440) represents the gram absorbance coefficient at a wavelength of 440nm].

In addition, the gram absorbance coefficient is measured by the method described in the embodiment.

The larger the ε(405) value, the easier it is for the compound to absorb light of 405nm wavelength, thereby inhibiting the degradation of optical laminates and image display devices in ultraviolet light or short-wavelength visible light. When the ε(405) value is less than 20L/(g.cm), if the content of the light selective absorber (B) in the adhesive composition is not increased, the phase difference film or organic EL light-emitting element tends to be difficult to exhibit the function of inhibiting degradation caused by ultraviolet light or short-wavelength visible light. The ε(405) value is preferably 20L/(g‧cm) or more, more preferably 30L/(g‧cm) or more, and even more preferably 40L/(g‧cm) or more, and is usually 500L/(g‧cm) or less.

The compound with a larger ε(405)/ε(440) value can absorb light near 405nm without hindering the color display of the image display device, and inhibit the light degradation of the display device such as the phase difference film or the organic EL element. The ε(405)/ε(440) value is preferably 20 or more, more preferably 40 or more, more preferably 70 or more, and particularly preferably 80 or more.

The compound that selectively absorbs light of wavelength 405nm is preferably a compound containing a merocyanine structure in the molecule. The molecular weight of the compound containing a merocyanine structure in the molecule is preferably 100 or more and 3000 or less. The compound containing a merocyanine structure in the molecule is a compound containing a partial structure represented by -(N-C=C-C=C)- in the molecule, such as merocyanine compounds, cyanine compounds, indole compounds, benzotriazole compounds, etc. Preferred are merocyanine compounds, cyanine compounds, and benzotriazole compounds, and more preferably are compounds represented by formula (I).

[In the formula, ^R1 and ^R5 independently represent a hydrogen atom, an alkyl group having 1 to 25 carbon atoms which may have a substituent, an aralkyl group having 7 to 15 carbon atoms which may have a substituent, an aryl group having 6 to 15 carbon atoms, or a heterocyclic group. The _-CH2- contained in the alkyl group or the aralkyl group may be substituted by ^-NR1A- , -CO-, _-SO2- , -O-, or -S-.

R ^1A represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.

^R2 , ^R3 and ^R4 independently represent a hydrogen atom, an alkyl group having 1 to 6 carbon atoms which may have a substituent, an aromatic hydrocarbon group which may have a substituent, or an aromatic heterocyclic group which may have a substituent. The _-CH2- in the alkyl group may be substituted by ^-NR1B- , -CO-, _-SO2- , -O- or -S-.

R ^1B represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.

^R6 and ^R7 each independently represent a hydrogen atom, an alkyl group having 1 to 25 carbon atoms, or an electron withdrawing group, or ^R6 and ^R7 may be linked to each other to form a ring structure.

^R1 and ^R2 may be linked to each other to form a ring structure, ^R2 and ^R3 may be linked to each other to form a ring structure, ^R2 and ^R4 may be linked to each other to form a ring structure, and ^R3 and ^R6 may be linked to each other to form a ring structure].

Examples of the alkyl group having 1 to 25 carbon atoms represented by ^R1 and ^R5 include methyl, ethyl, n-propyl, isopropyl, 2-cyanopropyl, n-butyl, t-butyl, sec-butyl, n-pentyl, n-hexyl, 1-methylbutyl, 3-methylbutyl, n-octyl, n-decyl, 2-hexyl-octyl and the like.

The substituents which the alkyl group having 1 to 25 carbon atoms represented by ^R1 and ^R5 may have include those listed in Group A below.

Group A: Examples include nitro, hydroxyl, carboxyl, sulfonic acid, cyano, amino, halogen atoms, alkoxy groups having 1 to 6 carbon atoms, alkylsilyl groups having 1 to 12 carbon atoms, alkylcarbonyl groups having 2 to 8 carbon atoms, and groups represented by *-R ^a1 -(OR ^a2 ) _t1 -R ^a3 (R ^a1 and R ^a2 each independently represent an alkanediyl group having 1 to 6 carbon atoms, R ^a3 represents an alkyl group having 1 to 6 carbon atoms, and t1 represents an integer from 1 to 3).

Alkyl silyl groups having 1 to 12 carbon atoms include: monoalkyl silyl groups such as methyl silyl, ethyl silyl, and propyl silyl; dialkyl silyl groups such as dimethyl silyl, diethyl silyl, and methylethyl silyl; and trialkyl silyl groups such as trimethyl silyl, triethyl silyl, and tripropyl silyl.

Examples of alkylcarbonyl groups with 2 to 8 carbon atoms include methylcarbonyl, ethylcarbonyl, etc.

Halogen atoms include fluorine atoms, chlorine atoms, bromine atoms, etc.

Examples of the aralkyl group having 7 to 15 carbon atoms represented by ^R1 and ^R5 include benzyl and phenylethyl. Examples of the group in which _-CH2- in the aralkyl group is replaced by _-SO2- or -COO- include ethyl 2-phenylacetate.

The substituents which the aralkyl group having 7 to 15 carbon atoms represented by ^R1 and ^R5 may have include those listed in Group A above.

Examples of the aryl group having 6 to 15 carbon atoms represented by ^R1 and ^R5 include phenyl, naphthyl, anthryl and the like.

The substituents which the aryl group having 6 to 15 carbon atoms represented by ^R1 and ^R5 may have include those listed in Group A above.

Examples of the heterocyclic group having 6 to 15 carbon atoms represented by ^R1 and ^R5 include aromatic heterocyclic groups having 3 to 9 carbon atoms such as pyridyl, pyrrolidinyl, quinolyl, thienyl, imidazolyl, oxazolyl, pyrrolyl, thiazolyl, and furyl.

Examples of the alkyl group having 1 to 6 carbon atoms represented by R ^1A and R ^1B include methyl, ethyl, n-propyl, isopropyl, n-butyl, t-butyl, sec-butyl, n-pentyl, and n-hexyl.

Examples of the alkyl group having 1 to 6 carbon atoms represented by R ² , R ³ and R ⁴ include the same alkyl group having 1 to 6 carbon atoms represented by R ^1B .

The substituents which the alkyl group having 1 to 6 carbon atoms represented by R ² , R ³ and R ⁴ may have include those listed in Group A above.

Examples of the aromatic hydrocarbon group represented by R ² , R ³ and R ⁴ include aryl groups having 6 to 15 carbon atoms such as phenyl, naphthyl and anthryl; and aralkyl groups having 7 to 15 carbon atoms such as benzyl and phenylethyl.

As the substituent which the aromatic hydrocarbon group represented by R ² , R ³ and R ⁴ may have, the substituents listed in the above group A can be given.

Examples of the aromatic heterocyclic group represented by R ² , R ³ and R ⁴ include aromatic heterocyclic groups having 3 to 9 carbon atoms such as pyridyl, pyrrolidinyl, quinolyl, thienyl, imidazolyl, oxazolyl, pyrrolyl, thiazolyl and furyl.

As the substituent which the aromatic heterocyclic ring represented by R ² , R ³ and R ⁴ may have, the substituents listed in the above group A can be given.

Examples of the alkyl group having 1 to 25 carbon atoms represented by ^R6 and ^R7 include the same ones as those mentioned above for the alkyl group having 1 to 25 carbon atoms represented by ^R1 and ^R5 .

The substituents which the alkyl group having 1 to 25 carbon atoms represented by R ⁶ and R ⁷ may have include those listed in Group A above.

Examples of the alkyl group having 1 to 25 carbon atoms represented by ^R6 and ^R7 include the same ones as those mentioned above for the alkyl group having 1 to 25 carbon atoms represented by ^R1 and ^R5 .

Examples of the electron withdrawing group represented by R ⁶ and R ⁷ include a cyano group, a nitro group, a halogen atom, an alkyl group substituted with a halogen atom, and a group represented by formula (I-1).

*-X ¹ -R ¹¹ (I-1)

[In the formula, R ¹¹ represents a hydrogen atom or an alkyl group having 1 to 25 carbon atoms, and at least one of the methylene groups contained in the alkyl group may be substituted by an oxygen atom.

X ¹ represents -CO-, -COO-, -OCO-, -CS-, -CSO-, -CSS-, -NR ¹² CO- or -CONR ¹³ -.

^R12 and ^R13 each independently represent a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or a phenyl group].

Halogen atoms include fluorine, chlorine, bromine, and iodine.

Examples of alkyl groups substituted with halogen atoms include trifluoromethyl, perfluoroethyl, perfluoropropyl, perfluoroisopropyl, perfluorobutyl, perfluorosec-butyl, perfluorotert-butyl, perfluoropentyl, and perfluorohexyl. The number of carbon atoms in alkyl groups substituted with halogen atoms is usually 1 to 25.

R ⁶ and R ⁷ may be linked to each other to form a ring structure. Examples of the ring structure formed by R ⁶ and R ⁷ include Meldrum's acid structure, barbituric acid structure, 5,5-dimethyl-1,3-cyclohexanedione (dimedone) structure, and the like.

Examples of the alkyl group having 1 to 25 carbon atoms represented by ^R11 include the same ones as those represented by ^R1 and ^R5 .

The ring structure formed by ^R2 and ^R3 being bonded to each other is a nitrogen-containing ring structure containing a nitrogen atom bonded to ^R2 , and examples thereof include a nitrogen-containing heterocyclic ring having 4 to 14 members. The ring structure formed by ^R2 and ^R3 being bonded to each other may be a monocyclic ring or a polycyclic ring. Specifically, examples thereof include a pyrrolidine ring, a pyrroline ring, an imidazoline ring, an imidazoline ring, an oxazoline ring, a thiazoline ring, a piperidine ring, a morpholine ring, a piperazine ring, an indole ring, an isoindole ring, and the like.

The ring structure formed by ^R1 and ^R2 being bonded to each other is a nitrogen-containing ring structure containing the nitrogen atom to which ^R1 and ^R2 are bonded, and examples thereof include a nitrogen-containing heterocyclic ring having 4 to 14 members (preferably 4 to 8 members). The ring structure formed by ^R1 and ^R2 being bonded to each other may be a monocyclic ring or a polycyclic ring. Specifically, examples thereof include the same ring structure as the ring structure formed by ^R2 and ^R3 being bonded to each other.

The ring structure formed by ^R2 and ^R4 bonding to each other can be a 4- to 14-membered nitrogen-containing ring structure, preferably a 5- to 9-membered nitrogen-containing ring structure. The ring structure formed by ^R2 and ^R4 bonding to each other can be a monocyclic or polycyclic ring. These rings may have a substituent, and the ring structure can be the same as the ring structure exemplified above for the ring structure formed by ^R2 and ^R3 .

The ring structure formed by R ³ and R ⁶ being linked to each other is a ring structure in which R ³ -C=CC=CR ⁶ forms a ring skeleton. Examples thereof include phenyl and the like.

Examples of the compound represented by formula (I) in which ^R2 and ^R3 are linked to each other to form a ring structure include the compound represented by formula (IA), and examples of the compound represented by formula (I) in which ^R2 and ^R4 are linked to each other to form a ring structure include the compound represented by formula (IB).

[In formula (IA) and formula (IB), R ¹ , R ³ , R ⁴ , R ⁵ , R ⁶ and R ⁷ have the same meanings as above.

Ring ^W1 and ring ^W2 each independently represent a nitrogen-containing ring].

Ring ^W1 and ring ^W2 represent nitrogen-containing rings containing nitrogen atoms as a ring constituent unit. Ring ^W1 and ring ^W2 may be monocyclic or polycyclic, and may contain heteroatoms other than nitrogen as a ring constituent unit. Ring ^W1 and ring ^W2 are preferably 5- to 9-membered rings, respectively and independently.

The compound represented by formula (I-A) is preferably a compound represented by formula (I-A-1).

[In formula (IA-1), R ¹ , R ⁴ , R ⁵ , R ⁶ and R ⁷ have the same meanings as above.

A ¹ represents -CH ₂ -, -O-, -S- or -NR ^1D -.

^R14 and ^R15 each independently represent a hydrogen atom or an alkyl group having 1 to 12 carbon atoms.

R ^1D represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms].

The compound represented by formula (I-B) is preferably a compound represented by formula (I-B-1) and a compound represented by formula (I-B-2).

[In the formula (IB-1), R ¹ , R ⁶ and R ⁷ have the same meanings as above.

R ¹⁶ each independently represents a hydrogen atom or an alkyl group or an aryl group having 1 to 12 carbon atoms].

[In formula (IB-2), R ³ , R ⁵ , R ⁶ and R ⁷ have the same meanings as above.

R ³⁰ represents a hydrogen atom, a cyano group, a nitro group, a halogen atom, a hydroxyl group, an amino group, an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, an aromatic hydrocarbon group having 6 to 18 carbon atoms, an acyl group having 2 to 13 carbon atoms, an acyloxy group having 2 to 13 carbon atoms, or an alkoxycarbonyl group having 2 to 13 carbon atoms.

R ³¹ represents an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, a hydroxyl group, an alkylthio group having 1 to 12 carbon atoms, an amino group or a heterocyclic group which may have a substituent].

Examples of the halogen atom represented by R ³⁰ include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom.

Examples of the acyl group having 2 to 13 carbon atoms represented by R ³⁰ include acetyl, propionyl and butyryl.

Examples of the acyloxy group having 2 to 13 carbon atoms represented by R ³⁰ include methylcarbonyloxy, ethylcarbonyloxy, propylcarbonyloxy, butylcarbonyloxy and the like.

Examples of the alkoxycarbonyl group having 2 to 13 carbon atoms represented by R ³⁰ include methoxycarbonyl, ethoxycarbonyl, propoxycarbonyl, butoxycarbonyl and the like.

Examples of the aromatic hydrocarbon group having 6 to 18 carbon atoms represented by R ³⁰ include aryl groups having 6 to 18 carbon atoms such as phenyl, naphthyl and biphenyl; and aralkyl groups having 7 to 18 carbon atoms such as benzyl and phenylethyl.

Examples of the alkyl group having 1 to 12 carbon atoms represented by R ³⁰ include the same ones as those for the alkyl group having 1 to 12 carbon atoms represented by R ¹⁴ .

Examples of the alkyl group having 1 to 12 carbon atoms represented by R ³⁰ include methoxy, ethoxy, propoxy, butoxy, pentyloxy and the like.

R ³⁰ is preferably an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, an amino group, or a hydroxyl group.

Examples of the alkyl group having 1 to 12 carbon atoms represented by R ³¹ include the same ones as the alkyl group having 1 to 12 carbon atoms represented by R ¹⁴ .

Examples of the alkoxy group having 1 to 12 carbon atoms represented by R ³¹ include the same alkoxy group having 1 to 12 carbon atoms represented by R ³⁰ .

Examples of the alkylthio group having 1 to 12 carbon atoms represented by R ³¹ include methylthio, ethylthio, propylthio, butylthio, pentylthio, hexylthio and the like.

Examples of the amino group which may have a substituent represented by R ³¹ include amino group; amino group substituted with one alkyl group having 1 to 8 carbon atoms, such as N-methylamino and N-ethylamino; amino group substituted with two alkyl groups having 1 to 8 carbon atoms, such as N,N-dimethylamino, N,N-diethylamino and N,N-methylethylamino.

Examples of the heterocyclic ring represented by R ³¹ include nitrogen-containing heterocyclic groups having 4 to 9 carbon atoms such as pyrrolidinyl, piperidinyl and morpholinyl.

Examples of the compound represented by formula (I) in which R ³ and R ⁶ are linked to each other to form a ring structure and R ² and R ⁴ are linked to each other to form a ring structure include the compound represented by formula (IC).

[In formula (IC), R ¹ , R ⁶ and R ⁷ have the same meanings as above.

R ²¹ and R ²² each independently represent a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, or a hydroxyl group.

X ² and X ³ each independently represent -CH ₂ - or -N(R ²⁵ )=.

^R25 represents a hydrogen atom, an alkyl group having 1 to 25 carbon atoms, or an aromatic hydrocarbon group which may have a substituent].

Examples of the alkyl group having 1 to 25 carbon atoms represented by R ²⁵ include the same ones as the alkyl group having 1 to 25 carbon atoms represented by R ¹ .

Examples of the aromatic hydrocarbon group represented by R ²⁵ include aryl groups such as phenyl and naphthyl; aralkyl groups such as benzyl and phenylethyl; and biphenyl groups. Preferably, the aromatic hydrocarbon group has 6 to 20 carbon atoms. Examples of the substituent that the aromatic hydrocarbon group represented by R ²⁵ may have include hydroxyl groups.

R ³ and R ⁶ are preferably independently an electron-withdrawing group.

Examples of the compound represented by formula (I) in which R ¹ and R ² are linked to each other to form a ring structure and R ³ and R ⁶ are linked to each other to form a ring structure include the compound represented by formula (ID).

[In formula (ID), R ⁴ , R ⁵ and R ⁷ have the same meanings as above.

R ²⁵ , R ²⁶ , R ²⁷ and R ²⁸ each independently represent a hydrogen atom, an alkyl group having 1 to 12 carbon atoms which may have a substituent, a hydroxyl group, or an aralkyl group].

Examples of the alkyl group having 1 to 12 carbon atoms represented by R ²⁵ , R ²⁶ , R ²⁷ and R ²⁸ include the same as the alkyl group having 1 to 12 carbon atoms represented by R ^1A and R ^1B . Examples of the substituent that the alkyl group having 1 to 12 carbon atoms represented by R ²⁵ , R ²⁶ , R ²⁷ and R ²⁸ may have include a hydroxyl group.

Examples of the aralkyl group represented by R ²⁵ , R ²⁶ , R ²⁷ and R ²⁸ include aralkyl groups having 7 to 15 carbon atoms such as benzyl and phenylethyl.

Examples of the compound (I) in which R ⁶ and R ⁷ are linked to each other to form a ring structure include the compound represented by formula (IE).

[In formula (IE), R ¹ , R ² , R ³ , R ⁴ and R ⁵ have the same meanings as above.

Ring W ³ represents a cyclic compound].

Ring W ³ is a 5- to 9-membered ring, and may contain a nitrogen atom, an oxygen atom, a sulfur atom or other impurity atom as a ring constituent unit.

The compound represented by formula (I-E) is preferably a compound represented by formula (IE-1).

[In formula (IE-1), R ¹ , R ² , R ³ and R ⁵ have the same meanings as above.

^R17 , ^R18 , ^R19 , and ^Rq each independently represent a hydrogen atom or an alkyl group, aralkyl group, or aryl group having 1 to 12 carbon atoms which may have a substituent. The _-CH2- group contained in the alkyl group or aralkyl group may be substituted by ^-NR1D- , -C(=O)-, -C(=S)-, -O-, or -S-. ^R17 and ^R18 may be linked to each other to form a ring structure, ^R18 and ^R19 may be linked to each other to form a ring structure, and ^R19 and ^Rq may be linked to each other to form a ring structure. m, p, and q each independently represent an integer from 0 to 3].

The compounds represented by formula (I) include the following compounds.

The total content of the light selective absorber is not limited if it is selected so that the absorbance of the adhesive layer at a wavelength of 410nm becomes 0.1 or more and 2.3 or less, but in the adhesive composition, for example, it is 0.01 to 20 parts by mass, preferably 0.05 to 15 parts by mass, and more preferably 0.1 to 10 parts by mass relative to 100 parts by mass of the whole resin component.

The mass ratio of the light selective absorber (A) to the light selective absorber (B) (light selective absorber (A)/light selective absorber (B)) is usually 0.05 to 20, preferably 0.1 to 10.

((Meth) acrylic resin (A))

The (meth)acrylic resin (A) is preferably a polymer having a structural unit derived from (meth)acrylate as the main component (preferably containing 50% by mass or more). The structural unit derived from (meth)acrylate may contain one or more structural units derived from monomers other than (meth)acrylate (for example, structural units derived from monomers having polar functional groups). In addition, in this specification, (meth)acrylic acid means either acrylic acid or methacrylic acid, and the same applies to "(meth)" in (meth)acrylate, etc.

Examples of (meth)acrylate include (meth)acrylate represented by the following formula (X).

[In formula (X), R ¹⁰¹ represents a hydrogen atom or a methyl group, and R ¹⁰² represents an alkyl group having 1 to 14 carbon atoms or an aralkyl group having 7 to 20 carbon atoms, and the hydrogen atom of the alkyl group or the aralkyl group may be substituted by an alkoxy group having 1 to 10 carbon atoms].

In formula (X), R ¹⁰² is preferably an alkyl group having 1 to 14 carbon atoms, more preferably an alkyl group having 1 to 8 carbon atoms.

The (meth)acrylate represented by formula (X) can be listed as follows:

Linear alkyl esters of (meth)acrylic acid, such as methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, n-butyl (meth)acrylate, n-pentyl (meth)acrylate, n-hexyl (meth)acrylate, n-heptyl (meth)acrylate, n-octyl (meth)acrylate, n-nonyl (meth)acrylate, n-decyl (meth)acrylate, n-dodecyl (meth)acrylate, lauryl (meth)acrylate, and stearyl (meth)acrylate;

Isopropyl (meth)acrylate, isobutyl (meth)acrylate, tert-butyl (meth)acrylate, isoamyl (meth)acrylate, isohexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isooctyl (meth)acrylate, isononyl (meth)acrylate, isostearyl (meth)acrylate, isoamyl (meth)acrylate and other branched alkyl esters of (meth)acrylate;

Alkyl esters of (meth)acrylic acid containing aliphatic ring skeletons such as cyclohexyl (meth)acrylate, isoborneol (meth)acrylate, adamantyl (meth)acrylate, dicyclopentyl (meth)acrylate, cyclododecyl (meth)acrylate, methylcyclohexyl (meth)acrylate, trimethylcyclohexyl (meth)acrylate, tert-butylcyclohexyl (meth)acrylate, α-ethoxycyclohexyl acrylate, etc.;

(Meth) acrylate phenyl ester and other (meth) acrylic acid esters containing aromatic ring skeletons, etc.

In addition, alkyl (meth)acrylates containing substituents can be cited, wherein the alkyl group in the alkyl (meth)acrylate is introduced with a substituent. The substituent of the alkyl (meth)acrylate containing substituents is a group that replaces the hydrogen atom of the alkyl group, and specific examples thereof include phenyl, alkoxy, and phenoxy. Specific examples of alkyl (meth)acrylates containing substituents include 2-methoxyethyl (meth)acrylate, ethoxymethyl (meth)acrylate, phenoxyethyl (meth)acrylate, 2-(2-phenoxyethoxy)ethyl (meth)acrylate, phenoxydiethylene glycol (meth)acrylate, phenoxypoly (ethylene glycol) (meth)acrylate, etc.

These (meth)acrylates may be used alone or in plural numbers.

The (meth)acrylic resin (A) preferably contains constituent units derived from an alkyl acrylate (a1) whose homopolymer has a glass transition temperature Tg of less than 0°C, and constituent units derived from an alkyl acrylate (a2) whose homopolymer has a Tg of more than 0°C. The constituent units derived from the alkyl acrylate (a1) and the constituent units derived from the alkyl acrylate (a2) are beneficial for improving the high-temperature durability of the adhesive layer. The Tg of the homopolymer of the alkyl (meth)acrylate can be, for example, the value in the literature such as POLYMER HANDBOOK (Wiley-Interscience).

Specific examples of acrylic acid alkyl esters (a1) include ethyl acrylate, n- and isopropyl acrylate, n- and isobutyl acrylate, n-pentyl acrylate, n- and isohexyl acrylate, n-heptyl acrylate, n- and isooctyl acrylate, 2-ethylhexyl acrylate, n- and isononyl acrylate, n- and isodecyl acrylate, n-dodecyl acrylate, and other acrylic acid alkyl esters having an alkyl carbon number of about 2 to 12.

Alkyl acrylate (a1) can be used alone or in combination of two or more. Among them, n-butyl acrylate, n-octyl acrylate, 2-ethylhexyl acrylate, etc. are preferred from the viewpoint of the followability or reworkability when the adhesive of the present invention is layered on an optical laminate.

Alkyl acrylate (a2) is an alkyl acrylate other than alkyl acrylate (a1). Specific examples of alkyl acrylate (a2) include methyl acrylate, cyclohexyl acrylate, isoborneol acrylate, stearyl acrylate, tert-butyl acrylate, etc.

Alkyl acrylate (a2) can be used alone or in combination of two or more. Among them, from the perspective of high-temperature durability, alkyl acrylate (a2) preferably contains methyl acrylate, cyclohexyl acrylate, isoborneol acrylate, etc., and more preferably contains methyl acrylate.

Among all structural units contained in the (meth)acrylic resin, the structural units derived from the (meth)acrylate represented by formula (X) are preferably 50% by mass or more, more preferably 60 to 95% by mass, and even more preferably 65 to 95% by mass or more.

The structural unit derived from a monomer other than (meth)acrylate is preferably a structural unit derived from a monomer having a polar functional group, and more preferably a structural unit derived from a (meth)acrylate having a polar functional group. The polar functional group may include a hydroxyl group, a carboxyl group, a substituted or unsubstituted amino group, a heterocyclic group such as an epoxide group, and the like.

Monomers with polar functional groups include:

1-Hydroxymethyl (meth)acrylate, 1-hydroxyethyl (meth)acrylate, 1-hydroxyheptyl (meth)acrylate, 1-hydroxybutyl (meth)acrylate, 1-hydroxypentyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 2-hydroxypentyl (meth)acrylate, 2-hydroxyhexyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 3-hydroxybutyl (meth)acrylate, 3-hydroxypentyl (meth)acrylate, 3-hydroxyhexyl (meth)acrylate, 3-hydroxyheptyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 4-hydroxypentyl (meth)acrylate, 4-hydroxyhexyl (meth)acrylate, 4 ...hexyl (meth)acrylate, 4-hydroxyhexyl (meth)acrylate, 4-hydroxyhexyl (meth)acrylate, 4-hydroxyhexyl (meth)acrylate, 4-hydroxyhexyl (meth)acrylate, 4-hydroxyhexyl (meth)acrylate, 4-hydroxyhexyl (meth)acrylate, 4-hydroxyhexyl (meth)acrylate, 4-hydroxyhexyl (meth)acrylate, 4-hydroxyhexyl (meth)acrylate, 4-hydroxyhexyl (meth)acrylate, 4-hydroxyhe -hydroxyheptyl (meth)acrylate, 4-hydroxyoctyl (meth)acrylate, 2-chloro-2-hydroxypropyl (meth)acrylate, 3-chloro-2-hydroxypropyl (meth)acrylate, 2-hydroxy-3-phenoxypropyl (meth)acrylate, 5-hydroxypentyl (meth)acrylate, 5-hydroxyhexyl (meth)acrylate, 5-hydroxyheptyl (meth)acrylate, 5-hydroxyoctyl (meth)acrylate, 5-hydroxynonyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, 6-hydroxyheptyl (meth)acrylate, 6-hydroxyoctyl (meth)acrylate, 6-hydroxynonyl (meth)acrylate, 6-hydroxydecyl (meth)acrylate, 7-hydroxyheptyl (meth)acrylate, 7-hydroxyoctyl (meth)acrylate, 7-hydroxynonyl (meth)acrylate, (meth)acrylate 7-hydroxydecyl (meth)acrylate, 7-hydroxyundecyl (meth)acrylate, 8-hydroxyoctyl (meth)acrylate, 8-hydroxynonyl (meth)acrylate, 8-hydroxydecyl (meth)acrylate, 8-hydroxyundecyl (meth)acrylate, 8-hydroxydodecyl (meth)acrylate, 9-hydroxynonyl (meth)acrylate, 9-hydroxydecyl (meth)acrylate, 9-hydroxyundecyl (meth)acrylate, 9-hydroxydodecyl (meth)acrylate, 9-hydroxytridecyl (meth)acrylate, 10-hydroxydecyl (meth)acrylate, 10-hydroxyundecyl (meth)acrylate, 10-hydroxydodecyl (meth)acrylate, 10-hydroxytridecyl (meth)acrylate, 10-hydroxytetradecyl (meth)acrylate, ) Monomers having a hydroxyl group such as 11-hydroxy undecyl (meth)acrylate, 11-hydroxy dodecyl (meth)acrylate, 11-hydroxy tridecyl (meth)acrylate, 11-hydroxy tetradecyl (meth)acrylate, 11-hydroxy pentadecyl (meth)acrylate, 12-hydroxy dodecyl (meth)acrylate, 12-hydroxy tridecyl (meth)acrylate, 12-hydroxy tetradecyl (meth)acrylate, 13-hydroxy pentadecyl (meth)acrylate, 13-hydroxy tetradecyl (meth)acrylate, 13-hydroxy pentadecyl (meth)acrylate, 14-hydroxy tetradecyl (meth)acrylate, 14-hydroxy pentadecyl (meth)acrylate, 15-hydroxy pentadecyl (meth)acrylate, and 15-hydroxy heptadecanyl (meth)acrylate;

Monomers having a carboxyl group such as (meth)acrylic acid, (meth)acrylic acid carboxyalkyl esters (e.g. (meth)acrylic acid carboxyethyl ester, (meth)acrylic acid carboxypentyl ester), maleic acid, maleic anhydride, fumaric acid, crotonic acid, etc.;

Monomers with heterocyclic groups such as acrylamide, vinyl caprolactam, N-vinyl-2-pyrrolidone, vinyl pyridine, tetrahydrofurfuryl (meth)acrylate, caprolactone-modified tetrahydrofurfuryl acrylate, 3,4-epoxycyclohexylmethyl (meth)acrylate, glycidyl (meth)acrylate, and 2,5-dihydrofuran;

Monomers with substituted or unsubstituted amino groups such as aminoethyl (meth)acrylate, N,N-dimethylaminoethyl (meth)acrylate, and dimethylaminopropyl (meth)acrylate.

Among them, from the perspective of the reactivity of the (meth)acrylate polymer and the crosslinking agent, a monomer having a hydroxyl group and/or a monomer having a carboxyl group is preferred, and a monomer containing both a hydroxyl group and a carboxyl group is more preferred.

The monomer having a hydroxyl group is preferably 2-hydroxyethyl acrylate, 3-hydroxypropyl acrylate, 4-hydroxybutyl acrylate, 5-hydroxypentyl acrylate, and 6-hydroxyhexyl acrylate. In particular, good durability can be obtained by using 2-hydroxyethyl acrylate, 4-hydroxybutyl acrylate, and 5-hydroxypentyl acrylate.

Acrylic acid is preferably used as a monomer having a carboxyl group.

From the viewpoint of preventing the peeling force of the separation film that can be deposited on the outer surface of the adhesive layer from increasing, the (meth)acrylic resin (A) preferably does not substantially contain a structural unit derived from a monomer having an amine group. Here, substantially not containing means that the amount is less than 0.1 parts by mass in 100 parts by mass of all the structural units constituting the (meth)acrylic resin (A).

The content of the structural units derived from the monomers having polar functional groups is preferably 20 parts by mass or less, more preferably 0.5 parts by mass or more and 15 parts by mass or less, still more preferably 0.5 parts by mass or more and 10 parts by mass or less, and particularly preferably 1 part by mass or more and 7 parts by mass or less, relative to 100 parts by mass of the total structural units of the (meth)acrylic resin (A).

The content of the structural unit derived from the monomer having an aromatic group is preferably 20 parts by mass or less, more preferably 4 parts by mass or more and 20 parts by mass or less, and even more preferably 4 parts by mass or more and 16 parts by mass or less, relative to 100 parts by mass of the total structural unit of the (meth) acrylic resin (A).

Structural units derived from monomers other than (meth)acrylates include structural units derived from styrene-based monomers, structural units derived from vinyl-based monomers, structural units derived from monomers having multiple (meth)acryl groups in the molecule, structural units derived from (meth)acrylamide-based monomers, etc.

Styrene monomers include: styrene; alkyl styrenes such as methyl styrene, dimethyl styrene, trimethyl styrene, ethyl styrene, diethyl styrene, triethyl styrene, propyl styrene, butyl styrene, hexyl styrene, heptyl styrene, octyl styrene; halogenated styrenes such as fluorostyrene, chlorostyrene, bromostyrene, dibromostyrene, iodostyrene; nitrostyrene; acetylstyrene; methoxystyrene; and divinylbenzene.

Vinyl monomers include: fatty acid vinyl esters such as vinyl acetate, vinyl propionate, vinyl butyrate, vinyl 2-ethylhexanoate, and vinyl laurate; halogenated vinyls such as vinyl chloride and vinyl bromide; dihalogenated vinyls such as vinylidene chloride; nitrogen-containing heteroaromatic vinyls such as vinyl pyridine, vinyl pyrrolidone, and vinyl carbazole; conjugated dienes such as butadiene, isoprene, and chloroprene; and unsaturated nitriles such as acrylonitrile and methacrylonitrile.

Examples of monomers with multiple (meth)acryloyl groups in the molecule include: 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, etc.; and trihydroxymethylpropane tri(meth)acrylate, etc., which have three (meth)acryloyl groups in the molecule.

Examples of (meth)acrylamide monomers include N-hydroxymethyl (meth)acrylamide, N-(2-hydroxyethyl) (meth)acrylamide, N-(3-hydroxypropyl) (meth)acrylamide, N-(4-hydroxybutyl) (meth)acrylamide, N-(5-hydroxypentyl) (meth)acrylamide, N-(6-hydroxyhexyl) (meth)acrylamide, N,N-dimethyl (meth)acrylamide, and N,N-diethyl (meth)acrylamide. , N-isopropyl (meth) acrylamide, N-(3-dimethylaminopropyl) (meth) acrylamide, N-(1,1-dimethyl-3-oxobutyl) (meth) acrylamide, N-〔2-(2-oxo-1-imidazolidinyl)ethyl〕(meth) acrylamide, 2-acrylamido-2-methyl-1-propanesulfonic acid, N-(methoxymethyl) acrylamide, N-(ethoxymethyl) (meth) acrylamide, N-(propoxy Methyl)(methyl) acrylamide, N-(1-methylethoxymethyl)(methyl)acrylamide, N-(1-methylpropoxymethyl)(methyl)acrylamide, N-(2-methylpropoxymethyl)(methyl)acrylamide, N-(butoxymethyl)(methyl)acrylamide, N-(1,1-dimethylethoxymethyl)(methyl)acrylamide, N-(2-methoxyethyl)(methyl)acrylamide, N-(2-ethoxyethyl)(methyl)acrylamide N-(2-propoxyethyl) (methyl) acrylamide, N-〔2-(1-methylethoxy) ethyl〕 (methyl) acrylamide, N-〔2-(1-methylpropoxy) ethyl〕 (methyl) acrylamide, N-〔2-(2-methylpropoxy) ethyl〕 (methyl) acrylamide, N-(2-butoxyethyl) (methyl) acrylamide, N-〔2-(1,1-dimethylethoxy) ethyl〕 (methyl) acrylamide, etc. Among them, N-(methoxymethyl) acrylamide, N-(ethoxymethyl) acrylamide, N-(propoxymethyl) acrylamide, N-(butoxymethyl) acrylamide, and N-(2-methylpropoxymethyl) acrylamide are preferred.

The weight average molecular weight (Mw) of the (meth)acrylic resin (A) is preferably 500,000 to 2.5 million. If the weight average molecular weight is 500,000 or more, the durability of the adhesive layer in a high temperature environment will be improved, and it is easy to suppress undesirable conditions such as floating and peeling between the adherend and the adhesive layer, or cohesive failure of the adhesive layer. If the weight average molecular weight is 2.5 million or less, it is advantageous from the perspective of coating properties. From the perspective of both the durability of the adhesive layer and the coating properties of the adhesive composition, the weight average molecular weight is preferably 600,000 to 1.8 million, more preferably 700,000 to 1.7 million, and particularly preferably 1 million to 1.6 million. In addition, the molecular weight distribution (Mw/Mn) represented by the ratio of the weight average molecular weight (Mw) to the number average molecular weight (Mn) is usually 2 to 10, preferably 3 to 8, and more preferably 3 to 6. The weight average molecular weight can be analyzed by gel permeation chromatography and is a standard polystyrene conversion value.

When the (meth)acrylic resin (A) is dissolved in ethyl acetate to form a solution with a concentration of 20 mass %, the viscosity at 25°C is preferably 20 Pa‧s or less, and more preferably 0.1 to 15 Pa‧s. If the viscosity is within this range, it is advantageous from the perspective of coating properties when the adhesive composition is coated on a substrate. In addition, the viscosity can be measured by a Brookfield viscometer.

The glass transition temperature (Tg) of the (meth) acrylic resin (A) is, for example, -60 to 20°C, preferably -50 to 15°C, more preferably -45 to 10°C, and particularly -40 to 0°C. If Tg is below the upper limit, it is beneficial to improve the wettability of the adhesive layer to the substrate of the adherend, and if it is above the lower limit, it is beneficial to improve the durability of the adhesive layer. In addition, the glass transition temperature can be measured by a differential scanning calorimeter (DSC).

(Meth) acrylic resin (A) can be produced by known methods such as solution polymerization, block polymerization, suspension polymerization, emulsion polymerization, etc., and solution polymerization is particularly preferred. Solution polymerization can be, for example, a method of mixing monomers and organic solvents, adding thermal polymerization initiators in a nitrogen environment, and stirring for about 3 to 15 hours at a temperature of 40 to 90°C (preferably about 50 to 80°C). In order to control the reaction, monomers or thermal polymerization initiators can be added continuously or intermittently during the polymerization. The monomer or thermal polymerization initiator can also be added to an organic solvent.

The polymerization initiator may be a thermal polymerization initiator or a photopolymerization initiator. Examples of the photopolymerization initiator include 4-(2-hydroxyethoxy)phenyl(2-hydroxy-2-propyl)ketone. Examples of the thermal polymerization initiator include 2,2'-azobisisobutyronitrile, 2,2'-azobis(2-methylbutyronitrile), 1,1'-azobis(cyclohexane-1-carbonitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), 2,2'-azobis(2,4-dimethyl-4-methoxyvaleronitrile), dimethyl-2,2'-azobis(2-methylpropionate), 2,2'-azobis(2-hydroxymethyl Azo compounds such as propionitrile); organic peroxides such as lauryl peroxide, tert-butyl hydroperoxide, benzoyl peroxide, tert-butyl perbenzoate, cumene hydroperoxide, diisopropyl peroxydicarbonate, dipropyl peroxydicarbonate, tert-butyl peroxyneodecanoate, tert-butyl peroxypivalate, (3,5,5-trimethylhexyl) peroxide; inorganic peroxides such as potassium persulfate, ammonium persulfate, hydrogen peroxide, etc. In addition, redox initiators that combine peroxides and reducing agents can be used.

The ratio of the polymerization initiator is about 0.001 to 5 parts by mass relative to 100 parts by mass of the total monomers constituting the (meth)acrylic resin (A). The polymerization of the (meth)acrylic resin can be carried out using a polymerization method using active energy rays (such as ultraviolet rays, etc.).

Organic solvents include: aromatic hydrocarbons such as toluene and xylene; esters such as ethyl acetate and butyl acetate; aliphatic alcohols such as propanol and isopropanol; ketones such as acetone, methyl ethyl ketone, and methyl isobutyl ketone, etc.

In 100% by mass of the adhesive composition, the content of the (meth)acrylic resin (A) is generally 60% by mass to 99.9% by mass, preferably 70% by mass to 99.5% by mass, and more preferably 80% by mass to 99% by mass.

The crosslinking agent (B) reacts with the polar functional groups (such as hydroxyl, amine, carboxyl, heterocyclic, etc.) in the (meth) acrylic resin (A). The crosslinking agent (B) forms a crosslinking structure with the (meth) acrylic resin, etc., thereby forming a crosslinking structure that is beneficial to durability or heavy workability.

The crosslinking agent (B) may include isocyanate crosslinking agents, epoxy crosslinking agents, aziridine crosslinking agents, metal chelate crosslinking agents, etc. In particular, from the perspective of the pot life of the adhesive composition, the durability of the adhesive layer, and the crosslinking speed, isocyanate crosslinking agents are preferred.

The isocyanate compound is preferably a compound having at least two isocyanate groups (-NCO) in the molecule, and examples thereof include aliphatic isocyanate compounds (e.g., hexamethylene diisocyanate, etc.), alicyclic isocyanate compounds (e.g., isophorone diisocyanate, hydrogenated diphenylmethane diisocyanate, hydrogenated xylylene diisocyanate), aromatic isocyanate compounds (e.g., toluene diisocyanate, xylylene diisocyanate, diphenylmethane diisocyanate, naphthalene diisocyanate, triphenylmethane triisocyanate, etc.), and the like. Furthermore, the crosslinking agent (B) may be an adduct of the aforementioned isocyanate compound using a polyol compound [e.g., an adduct using glycerol, trihydroxymethylpropane, etc.], an isocyanurate compound, a biuret compound, or a derivative such as a urethane prepolymer type isocyanate compound obtained by addition reaction of the isocyanate compound with a polyether polyol, a polyester polyol, an acrylic polyol, a polybutadiene polyol, a polyisoprene polyol, etc. The crosslinking agent (B) may be used alone or in combination of two or more. Representative examples of these include aromatic isocyanate compounds (e.g., toluene diisocyanate, xylylene diisocyanate), aliphatic isocyanate compounds (e.g., hexamethylene diisocyanate), or adducts formed from these using polyol compounds (e.g., glycerol, trihydroxymethylpropane), or isocyanurates. If the crosslinking agent (B) is an aromatic isocyanate compound and/or an adduct formed from these using polyol compounds, or isocyanurates, it is beneficial to form the most suitable crosslinking density (or crosslinking structure), which can improve the durability of the adhesive layer. In particular, if it is a toluene diisocyanate compound and/or an adduct formed from these using polyol compounds, for example, even when the adhesive layer is applied to a polarizing plate, the durability can be improved.

Relative to 100 parts by mass of (meth)acrylic resin (A), the content of crosslinking agent (B) is usually 0.01 to 15 parts by mass, preferably 0.05 to 10 parts by mass, and more preferably 0.1 to 5 parts by mass.

The adhesive composition that forms the light selective absorption adhesive layer of the present invention may further contain a silane compound (D).

Silane compounds (D) include, for example, vinyl trimethoxysilane, vinyl triethoxysilane, vinyl tri(2-methoxyethoxy)silane, 3-glycidyloxypropyl trimethoxysilane, 3- glycidyloxypropyl triethoxysilane, 3-glycidyloxypropyl methyl dimethoxysilane, 3-glycidyloxypropyl ethoxy dimethyl silane, 2-(3,4-epoxycyclohexyl)ethyl trimethoxysilane, 3-chloropropyl methyl dimethoxysilane, 3-chloropropyl trimethoxysilane, 3-methacryloyloxypropyl trimethoxysilane, 3-butyl propyl trimethoxysilane, etc.

The silane compound (D) may be a polysiloxane oligomer. If a specific example of a polysiloxane oligomer is represented in the form of a combination of monomers, it is as follows.

Oligomers containing 3-butylpropyltrimethoxysilane/tetramethoxysilane oligomers, 3-butylpropyltrimethoxysilane/tetraethoxysilane oligomers, 3-butylpropyltriethoxysilane/tetramethoxysilane oligomers, 3-butylpropyltriethoxysilane/tetraethoxysilane oligomers, etc.; oligomers containing 3-butylpropyltrimethoxysilane/tetramethoxysilane oligomers, 3-butylpropyltriethoxysilane/tetraethoxysilane oligomers; oligomers containing 3-butylpropyltrimethoxysilane/tetramethoxysilane oligomers, 3-butylpropyltriethoxysilane/tetraethoxysilane oligomers; oligomers containing 3-butylpropyltrimethoxysilane/tetramethoxysilane oligomers, 3-butylpropyltriethoxysilane/tetrameth ... oligomers containing methyl groups, such as triethoxysilane/tetraethoxysilane oligomers; 3-glycidyloxypropyl trimethoxysilane/tetramethoxysilane copolymers, 3-glycidyloxypropyl trimethoxysilane/tetraethoxysilane copolymers, 3-glycidyloxypropyl triethoxysilane/tetramethoxysilane copolymers, 3-glycidyloxypropyl triethoxysilane/tetraethoxysilane copolymers, 3-glycidyloxypropyl methyl dimethoxysilane Silane/tetramethoxysilane copolymers, 3-glycidyloxypropylmethyldimethoxysilane/tetraethoxysilane copolymers, 3-glycidyloxypropylmethyldiethoxysilane/tetramethoxysilane copolymers, 3-glycidyloxypropylmethyldiethoxysilane/tetraethoxysilane copolymers, and other copolymers containing 3-glycidyloxypropyl groups; 3-methacryloxypropyltrimethoxysilane/tetramethoxysilane oligomers, 3-methacryloxypropyltrimethoxysilane/tetramethoxysilane oligomers, 3-Methacryloyloxypropyltriethoxysilane/tetramethoxysilane oligomer, 3-Methacryloyloxypropyltriethoxysilane/tetramethoxysilane oligomer, 3-Methacryloyloxypropylmethyldimethoxysilane/tetramethoxysilane oligomer, 3-Methacryloyloxypropylmethyldimethoxysilane/tetraethoxysilane oligomer, 3-Methacryloyloxypropylmethyldiethoxysilane/tetramethoxysilane oligomer, 3-acryloxypropyl trimethoxysilane/tetramethoxysilane oligomer, 3-acryloxypropyl trimethoxysilane/tetraethoxysilane oligomer, 3-acryloxypropyl triethoxysilane/tetramethoxysilane oligomer, 3-acryloxypropyl triethoxysilane/tetramethoxysilane oligomer, 3-acryloxypropyl methyl dimethoxysilane Oligomers containing acryloxypropyl groups, such as 3-acryloxypropylmethyldimethoxysilane/tetramethoxysilane oligomers, 3-acryloxypropylmethyldiethoxysilane/tetramethoxysilane oligomers, 3-acryloxypropylmethyldiethoxysilane/tetraethoxysilane oligomers; oligomers containing vinyl trimethoxysilane/tetramethoxysilane oligomers, vinyl trimethoxysilane/tetraethoxysilane oligomers, vinyl triethoxysilane/tetramethoxysilane oligomers; Silane oligomers, vinyl triethoxysilane/tetraethoxysilane oligomers, vinyl methyl dimethoxysilane/tetramethoxysilane oligomers, vinyl methyl dimethoxysilane/tetraethoxysilane oligomers, vinyl methyl diethoxysilane/tetramethoxysilane oligomers, vinyl methyl diethoxysilane/tetraethoxysilane oligomers and other oligomers containing vinyl groups; 3-aminopropyl trimethoxysilane/tetramethoxysilane copolymers, 3-aminopropyl trimethoxysilane/tetraethoxysilane copolymers Silane copolymers, 3-aminopropyl triethoxysilane/tetramethoxysilane copolymers, 3-aminopropyl triethoxysilane/tetraethoxysilane copolymers, 3-aminopropyl methyl dimethoxysilane/tetramethoxysilane copolymers, 3-aminopropyl methyl dimethoxysilane/tetraethoxysilane copolymers, 3-aminopropyl methyl diethoxysilane/tetramethoxysilane copolymers, 3-aminopropyl methyl diethoxysilane/tetraethoxysilane copolymers, and other copolymers containing amino groups.

The silane compound (D) may be a silane compound represented by the following formula (d1). If the adhesive composition contains a silane compound represented by the following formula (d1), the adhesion to the substrate, glass, transparent electrode, etc. can be further improved, so that a durable adhesive layer that is not prone to floating, peeling, or foaming in a high temperature environment can be formed.

(wherein B represents an alkanediyl group having 1 to 20 carbon atoms or a divalent alicyclic alkyl group having 3 to 20 carbon atoms, the _-CH2- constituting the aforementioned alkanediyl group and the aforementioned alicyclic alkyl group may be substituted by -O- or -CO-, ^Rd7 represents an alkyl group having 1 to 5 carbon atoms, and ^Rd8 , ^Rd9 , ^Rd10 , ^Rd11 and ^Rd12 independently represent an alkyl group having 1 to 5 carbon atoms or an alkoxy group having 1 to 5 carbon atoms).

In formula (d1), B represents an alkanediyl group having 1 to 20 carbon atoms, such as methylene, ethylene, trimethylene, tetramethylene, hexamethylene, heptamethylene, octamethylene, etc.; a divalent alicyclic alkyl group having 3 to 20 carbon atoms, such as cyclobutylene (e.g., 1,2-cyclobutylene), cyclopentylene (e.g., 1,2-cyclopentylene), cyclohexylene (e.g., 1,2-cyclohexylene), cyclooctylene (e.g., 1,2-cyclooctylene), or a group in which -CH ₂ - constituting such an alkanediyl group and the aforementioned alicyclic alkyl group is substituted with -O- or -CO-. Preferably, B is an alkanediyl group having 1 to 10 carbon atoms. ^Rd7 represents an alkyl group having 1 to 5 carbon atoms, such as methyl, ethyl, propyl, isopropyl, butyl, sec-butyl, tert-butyl, and pentyl. ^Rd8 , ^Rd9 , ^Rd10 , ^Rd11 , and ^Rd12 each independently represent an alkyl group having 1 to 5 carbon atoms, such as exemplified by ^R21 , or an alkoxy group having 1 to 5 carbon atoms, such as methoxy, ethoxy, propoxy, isopropoxy, butoxy, sec-butoxy, and tert-butoxy. Preferably, ^Rd8 , ^Rd9 , ^Rd10 , ^Rd11 , and ^Rd12 each independently represent an alkoxy group having 1 to 5 carbon atoms. The silane compounds (D) may be used alone or in combination of two or more.

Specific examples of the silane compound represented by the above formula (d1) include (trimethoxysilyl)methane, 1,2-bis(trimethoxysilyl)ethane, 1,2-bis(triethoxysilyl)ethane, 1,3-bis(trimethoxysilyl)propane, 1,3-bis(triethoxysilyl)propane, 1,4-bis(trimethoxysilyl)butane, 1,4-bis(triethoxysilyl)butane, 1 ,5-bis(trimethoxysilyl)pentane, 1,5-bis(triethoxysilyl)pentane, 1,6-bis(trimethoxysilyl)hexane, 1,6-bis(triethoxysilyl)hexane, 1,6-bis(tripropoxysilyl)hexane, 1,8-bis(trimethoxysilyl)octane, 1,8-bis(triethoxysilyl)octane, 1,8-bis(tripropoxysilyl)octane and other bis(triC1 -5 alkoxysilyl) C1-10 alkane; bis(dimethoxymethylsilyl)methane, 1,2-bis(dimethoxymethylsilyl)ethane, 1,2-bis(dimethoxyethylsilyl)ethane, 1,4-bis(dimethoxymethylsilyl)butane, 1,4-bis(dimethoxyethylsilyl)butane, 1,6-bis(dimethoxymethylsilyl)hexane, 1,6-bis(dimethoxyethylsilyl) C1-10 alkanes such as bis(di-C1-5 alkoxy-C1-5 alkylsilyl)C1-10 alkanes such as 1,6-bis(methoxydimethylsilyl)hexane and 1,8-bis(methoxydimethylsilyl)octane; and bis(mono-C1-5 alkoxy-di-C1-5 alkylsilyl)C1-10 alkanes such as 1,6-bis(methoxydimethylsilyl)hexane and 1,8-bis(methoxydimethylsilyl)octane. Among these, preferred are bis(triC1-3 alkoxysilyl)C1-10 alkanes such as 1,2-bis(trimethoxysilyl)ethane, 1,3-bis(trimethoxysilyl)propane, 1,4-bis(trimethoxysilyl)butane, 1,5-bis(trimethoxysilyl)pentane, 1,6-bis(trimethoxysilyl)hexane, and 1,8-bis(trimethoxysilyl)octane, and particularly preferred are 1,6-bis(trimethoxysilyl)hexane and 1,8-bis(trimethoxysilyl)octane.

The content of the silane compound (D) is usually 0.01 to 10 parts by mass, preferably 0.03 to 5 parts by mass, more preferably 0.05 to 2 parts by mass, and even more preferably 0.1 to 1 part by mass relative to 100 parts by mass of the (meth) acrylic resin (A). If it is below the upper limit, it is beneficial to suppress the permeation of the silane compound (A) from the adhesive layer. If it is above the lower limit, it is easy to improve the adhesion (or bonding) between the adhesive layer and the metal layer or glass substrate, etc., which is beneficial to improve the peeling resistance, etc.

The adhesive composition may further contain an antistatic agent.

Examples of antistatic agents include surfactants, silicone compounds, conductive polymers, ionic compounds, etc., and ionic compounds are preferred. Examples of ionic compounds include conventional ones. Examples of cationic components constituting ionic compounds include organic cations, inorganic cations, etc. Examples of organic cations include pyridinium cations, pyrrolidinium cations, piperidinium cations, imidazolium cations, ammonium cations, cobalt cations, and phosphonium cations. Examples of the inorganic cation include alkali metal cations such as lithium cations, potassium cations, sodium cations, and cesium cations, and alkaline earth metal cations such as magnesium cations and calcium cations. In particular, from the viewpoint of compatibility with (meth)acrylic resins, pyridinium cations, imidazolium cations, pyrrolidinium cations, lithium cations, and potassium cations are preferred. The anionic component constituting the ionic compound may be any of an inorganic anion and an organic anion, but from the viewpoint of antistatic performance, an anionic component containing fluorine atoms is preferred. Examples of anionic components containing fluorine atoms include hexafluorophosphate anion (PF ₆ -), bis(trifluoromethanesulfonyl)imide anion [(CF ₃ SO ₂ ) ₂ N-], bis(fluorosulfonyl)imide anion [(FSO ₂ ) ₂ N-], tetrakis(pentafluorophenyl)borate anion [(C ₆ F ₅ ) ₄ B-], and the like. Such ionic compounds may be used alone or in combination of two or more. Particularly preferred are bis(trifluoromethanesulfonyl)imide anion [(CF ₃ SO ₂ ) ₂ N-], bis(fluorosulfonyl)imide anion [(FSO ₂ ) ₂ N-], and tetrakis(pentafluorophenyl)borate anion [(C ₆ F ₅ ) ₄ B-].

From the perspective of the time-dependent stability of the antistatic performance of the adhesive layer formed by the adhesive composition, an ionic compound that is solid at room temperature is preferred.

Relative to 100 parts by mass of (meth)acrylic resin (A), the content of antistatic agent is, for example, 0.01 to 20 parts by mass, preferably 0.1 to 10 parts by mass, and more preferably 1 to 7 parts by mass.

The adhesive composition may contain one or more solvents, crosslinking catalysts, thickeners, plasticizers, softeners, pigments, rustproofing agents, inorganic fillers, light scattering microparticles and other additives.

[Middle layer]

The optical laminate of the present invention has an intermediate layer 300. The optical laminate of the present invention has the intermediate layer 300 interposed between the polarizer 10 and the light selective absorbing adhesive layer 20, thereby having the effect of inhibiting the light selective absorber contained in the light selective absorbing adhesive layer 20 from being transferred to the polarizer 10. However, the intermediate layer 300 is only composed of one or more layers selected from the group consisting of a liquid crystal curing layer, an alignment layer, and a bonding layer, rather than a structure that completely blocks the penetration of the light selective absorber, so the inhibition effect is not sufficient. In the optical multilayer of the present invention, the color fading at the end of the polarizer under high temperature and high humidity can be suppressed by adjusting the absorbance of the light selective absorption adhesive layer.

The thickness of the intermediate layer 300 is not limited, but is, for example, greater than 1 μm and less than 200 μm. From the perspective of suppressing the transfer of the light selective absorber contained in the light selective absorber adhesive layer, it is preferably greater than 5 μm and less than 200 μm.

From the viewpoint of suppressing discoloration of the polarizer 10, the intermediate layer 300 preferably does not contain a light selective absorber. When containing a light selective absorber, the content of the light selective absorber per unit area is preferably 0.5 g/ ^m2 or less.

[Liquid crystal hardening layer]

The optical multilayer of the present invention may have a liquid crystal curing layer as an intermediate layer. The liquid crystal curing layer may be one layer or two layers or more. The optical multilayer 101 shown in FIG. 2 has a first liquid crystal curing layer 30 and a second liquid crystal curing layer 31.

The liquid crystal curing layer is a layer of cured polymerizable liquid crystal compounds, such as a phase difference layer.

The phase difference layer of the cured polymerizable liquid crystal compound can present the first to fifth forms.

First form: a phase difference layer in which the rod-shaped liquid crystal compound is aligned in the horizontal direction relative to the supporting substrate.

Second form: a phase difference layer in which the rod-shaped liquid crystal compound is aligned in a vertical direction relative to the supporting substrate.

The third form: a phase difference layer in which the rod-shaped liquid crystal compound changes its orientation in a spiral shape within the plane.

The fourth form: a phase difference layer with tilted alignment of discotic liquid crystal compounds.

Fifth form: a biaxial phase difference layer in which the discotic liquid crystal compound is aligned in a vertical direction relative to the supporting substrate.

For example, the optical multilayer used in the organic electroluminescent display is suitable for using the first form, the second form, and the fifth form. Alternatively, the phase difference layer of these forms can be stacked for use.

The phase difference layer preferably has reverse wavelength dispersion. Reverse wavelength dispersion refers to the optical property that the phase difference value in the liquid crystal alignment plane of short wavelength is smaller than the phase difference value in the liquid crystal alignment plane of long wavelength. It is preferred that the phase difference layer satisfies the following equations (7) and (8). In addition, Re(λ) represents the in-plane phase difference value for light of wavelength λnm.

Re(450)/Re(550)≦1 (7)

1≦Re(630)/Re(550) (8)

In the optical multilayer of the present invention, when the phase difference layer is in the first form and has reverse wavelength dispersion, it is better because it will reduce the coloring when the display device is displayed in black. In the above formula (7), it is more preferable to be 0.82≦Re(450)/Re(550)≦0.93. It is more preferable to be 120≦Re(550)≦150.

The polymerizable liquid crystal compounds used to form the phase difference layer include: compounds having a polymerizable group in "3.8.6 Network Completely Crosslinked Type)" and "6.5.1 Liquid Crystal Material b. Polymerizable Nematic Liquid Crystal Material" of Liquid Crystal Handbook (Edited by Liquid Crystal Handbook Editorial Committee, Maruzen Co., Ltd., issued on October 30, 2001); and compounds having a polymerizable group in Japanese Patent Publication No. 2010-31223, ... The polymerizable liquid crystal compounds described in Japanese Patent Publication No. 2010-270108, Japanese Patent Publication No. 2011-6360, Japanese Patent Publication No. 2011-207765, Japanese Patent Publication No. 2011-162678, Japanese Patent Publication No. 2016-81035, International Publication No. 2017/043438, and Japanese Patent Table No. 2011-207765, etc.

The method of making a phase difference layer from a polymer in an aligned state of a polymerizable liquid crystal compound can be exemplified by the method described in Japanese Patent Publication No. 2010-31223.

The thickness of the phase difference layer of the liquid crystal curing layer formed by curing the polymerizable liquid crystal compound is, for example, 0.1 μm to 10 μm, preferably 0.5 μm to 8 μm, and more preferably 1 μm to 6 μm.

The phase difference layer can be a λ/4 phase difference layer that gives a phase difference of 1/4 wavelength to the transmitted light, a λ/2 phase difference layer that gives a phase difference of 1/2 wavelength to the transmitted light, a positive A plate, and a positive C plate. When the optical multilayer 101 shown in FIG. 2 contains a first liquid crystal curing layer 30 and a second liquid crystal curing layer 31, the combination of the first liquid crystal curing layer 30 and the second liquid crystal curing layer 31 can be a combination of a λ/2 phase difference layer and a λ/4 phase difference layer, a combination of a λ/4 phase difference layer and a positive C layer, etc.

The optical multilayer of the present invention can be constructed as a circular polarizing plate with a λ/4 phase difference layer. The circular polarizing plate can be used as an anti-reflection polarizing plate.

[Orientation layer]

The alignment layer has an alignment limiting force that allows the liquid crystal compound contained in the liquid crystal curing layer to be formed on the alignment layer to align the liquid crystal in the desired direction. The alignment layer can include an alignment polymer layer formed by an alignment polymer, a photoalignment polymer layer formed by a photoalignment polymer, and a groove alignment layer having a concave-convex pattern or a plurality of grooves on the surface of the layer. The thickness of the alignment layer is usually 0.01 to 10μm, preferably 0.01 to 5μm.

The composition formed by dissolving the alignment polymer in a solvent can be applied to the substrate layer, the solvent can be removed, and a friction treatment can be performed as needed to form an alignment polymer layer. At this time, in the alignment polymer layer formed by the alignment polymer, the alignment restriction force can be arbitrarily adjusted according to the surface state of the alignment polymer or the friction conditions.

A composition containing a polymer or monomer with a photoreactive group and a solvent is applied to a substrate layer and irradiated with polarized light to form a photo-aligned polymer layer. At this time, the alignment restriction force in the photo-aligned polymer layer can be arbitrarily adjusted according to the polarized light irradiation conditions for the photo-aligned polymer.

The groove alignment layer can be formed by, for example, the following methods: a method of forming a concave-convex pattern by exposing and developing the surface of a photosensitive polyimide film through an exposure mask having a narrow slit in the shape of a pattern; a method of forming an uncured layer of an active energy ray-curable resin on a plate-shaped master having grooves on the surface, transferring the layer to a substrate layer and curing the layer; a method of forming an uncured layer of an active energy ray-curable resin on a substrate layer, pressing a roll-shaped master having concave-convex patterns on the layer, and curing the concave-convex patterns, etc.

The substrate layer is preferably a film formed of a resin material. The resin material may be, for example, a resin material having excellent transparency, mechanical strength, thermal stability, and elongation. Specifically, the following may be mentioned: polyolefin resins such as polyethylene and polypropylene; cyclic polyolefin resins such as norbornene polymers; polyester resins such as polyethylene terephthalate and polyethylene naphthalate; (meth)acrylic acid resins such as (meth)acrylic acid and polymethyl (meth)acrylate; cellulose triacetate, cellulose diacetate, and cellulose acetate propionate. Cellulose ester resins such as cellulose ester resins; vinyl alcohol resins such as polyvinyl alcohol and polyvinyl acetate; polycarbonate resins; polystyrene resins; polyarylate resins; polysulfone resins; polyethersulfone resins; polyamide resins; polyimide resins; polyetherketone resins; polyphenylene sulfide resins; polyphenylene ether resins, and mixtures and copolymers thereof. Among these resins, it is preferred to use any one of cyclic polyolefin resins, polyester resins, cellulose ester resins, and (meth)acrylic resins, or mixtures thereof. In addition, the above-mentioned "(meth)acrylic acid" means "at least one of acrylic acid and methacrylic acid".

The substrate layer may be a single layer of one or a mixture of two or more of the above resins, or may have a multi-layer structure of two or more layers. When having a multi-layer structure, the resins constituting each layer may be the same or different.

Any additives may be added to the resin material forming the resin film. Examples of additives include light selective absorbers, antioxidants, lubricants, plasticizers, mold release agents, anti-coloring agents, flame retardants, nucleating agents, antistatic agents, pigments, and coloring agents.

The thickness of the substrate layer is not particularly limited. Generally speaking, from the perspective of strength or operability, it is preferably 5 to 200 μm, more preferably 10 to 200 μm, and even more preferably 10 to 150 μm.

In order to improve the adhesion between the substrate layer and the alignment layer, the surface of the substrate layer on which the alignment layer is to be formed may be subjected to corona treatment, plasma treatment, flame treatment, etc., or a primer layer may be formed. The substrate layer may be peeled off from the layer structure composed of the substrate layer/alignment layer/liquid crystal curing layer, and the alignment layer/liquid crystal curing layer may be used as the constituent element of the intermediate layer of the present invention. Alternatively, the substrate layer/alignment layer may be peeled off, and the liquid crystal curing layer may be used as the constituent element of the intermediate layer of the present invention.

[Lamination layer]

The intermediate layer 300 may contain a bonding layer for bonding two layers. The bonding layer may include a bonding agent layer, an adhesive layer (hereinafter, also referred to as a "second adhesive layer"), etc. The optical multilayer body 101 shown in FIG. 2 has a bonding agent layer 33 interposed between the first liquid crystal curing layer 30 and the second liquid crystal curing layer 31 and bonding these bonding agents, and a second adhesive layer 32 laminated on the surface of the first liquid crystal curing layer 30 on the opposite side of the bonding agent layer 33.

The adhesive layer may use a water-based adhesive, an active energy ray-hardening adhesive, or a heat-hardening adhesive. The thickness of the adhesive layer is, for example, greater than 10 nm and less than 20 μm, preferably greater than 100 nm and less than 10 μm, and more preferably greater than 500 nm and less than 5 μm.

The second adhesive layer may be composed of the same adhesive composition as the adhesive composition forming the above-mentioned light selective absorption adhesive layer, or may be composed of an adhesive composition having a resin such as (meth) acrylic acid, rubber, urethane, ester, silicone, or polyvinyl ether as a main component (hereinafter also referred to as "the second adhesive composition"). The second adhesive composition is preferably an adhesive composition having a (meth) acrylic resin having excellent transparency, weather resistance, heat resistance, etc. as a base polymer. The second adhesive composition may be an active energy ray curing type or a heat curing type. The thickness of the second adhesive layer is, for example, 0.1 to 150 μm, usually 8 to 60 μm, and from the perspective of thinning, it is less than 30 μm, preferably less than 20 μm.

In the second adhesive layer, from the perspective of suppressing discoloration of the polarizer 10, it is preferred that the light selective absorber is not contained. When the light selective absorber is contained, the amount thereof is preferably less than 0.5 parts by mass relative to 100 parts by mass of the total resin component per unit area of the light selective absorber.

<Method for manufacturing optical multilayer body>

The optical laminates 100, 101, and 102 can be manufactured by a method including a step of bonding the constituent layers to each other via a bonding layer. In addition, the method may include a step of peeling off a layer other than the constituent layer. When bonding the layers to each other via a bonding layer, in order to improve adhesion, it is preferred to perform a surface activation treatment such as a corona treatment on one or both bonding surfaces.

<Optical layered structure>

The optical multilayer of the present invention is planar, and its area is, for example, 30 mm × 30 mm to 180 mm × 90 mm. The optical multilayer of the present invention can be a rectangle such as a rectangle or a square, or can be a so-called irregular shape such as a shape in which a portion of the sides constituting the rectangle has a cutout portion, a semicircular shape, or a shape with a through hole in the surface. When the outer shape of the optical multilayer has a straight edge, the absorption axis of the polarizer constituting the optical multilayer can be parallel or orthogonal to the edge, or can be tilted, for example, crossing at an angle of 45°. When the optical stack has a phase difference layer and the phase difference layer has a slow axis in the plane, the slow axis and the absorption axis of the polarizer constituting the optical stack can intersect at 45°, 15°, or 75°.

<Image display device>

The optical laminates 100, 101, and 102 are arranged on the front surface (visual recognition side) of the image display panel and can be used as a component of the image display device. The optical laminate, which is a circular polarizer, can also be used as an anti-reflection polarizer for imparting an anti-reflection function in the image display device. The image display device is not particularly limited, and examples thereof include organic electroluminescent (organic EL) display devices, inorganic electroluminescent (inorganic EL) display devices, liquid crystal display devices, electroluminescent display devices, and other image display devices.

[Implementation example]

Although the present invention is described in more detail below with reference to the following examples, the present invention is not limited thereto. The "%" and "parts" in the examples and comparative examples are "mass %" and "mass parts" unless otherwise specified.

[Production of single-sided protected polarizing plate]

(Production of polarizing film)

A polyvinyl alcohol film with a thickness of 20 μm, a degree of polymerization of 2400, and a saponification degree of more than 99% was uniaxially stretched on a hot roller to a stretching ratio of 4.1 times, and then immersed in a dyeing bath containing 0.05 weight parts of iodine and 5 weight parts of potassium iodide per 100 weight parts of water at 28°C for 60 seconds while being kept tightly stretched.

Then, it was immersed in a boric acid aqueous solution 1 containing 5.5 parts by weight of boric acid and 15 parts by weight of potassium iodide per 100 parts by weight of water at 64°C for 110 seconds. Then, it was immersed in a boric acid aqueous solution 2 containing 5.5 parts by weight of boric acid and 15 parts by weight of potassium iodide per 100 parts by weight of water at 67°C for 30 seconds. Thereafter, it was washed with 10°C pure water and dried to obtain a polarizer. The thickness of the obtained polarizer was 8μm and the boron content was 4.3% by weight.

(Preparation of water-based adhesives)

3 parts by weight of carboxyl-modified polyvinyl alcohol (Kuraray Co., Ltd., trade name "KL-318") was dissolved in 100 parts by weight of water, and 1.5 parts by weight of polyamide epoxy additive (Taoka Chemical Industry Co., Ltd., trade name "Sumirez Resin (registered trademark) 650 (30), a 30% by weight aqueous solution of solid content concentration) which is a water-soluble epoxy resin was added to the aqueous solution to prepare a water-based adhesive.

(Protective film A and peeling film B)

Protective film A uses a film in which a 3μm thick hard coating layer is formed on a stretched film composed of a norbornene resin with a thickness of 25μm (manufactured by Nippon Paper Industries, Ltd., trade name "COP25ST-HC").

A cellulose triacetate membrane (manufactured by FUJIFILM Co., Ltd., "TD80UL") was used as the peeling membrane B. The thickness of the peeling membrane was 80 μm, and the moisture permeability was 502 g/m ² ‧24 hr.

(Production of single-sided protected polarizing plate)

While the produced polarizer is continuously conveyed, the protective film A is continuously pulled out from the roll of protective film A, and the release film B is continuously pulled out from the roll of release film B. While the water-based adhesive is injected between the polarizer and the protective film A treated with corona, pure water is injected between the polarizer and the release film B, and a laminated film consisting of protective film A/water-based adhesive/polarizer/pure water/release film B is obtained by laminating the rolls. The laminated film is transported and heated in a drying oven at 80°C for 300 seconds to dry the aqueous adhesive and volatilize and remove the pure water between the polarizer and the release film B, thereby obtaining a single-sided protected polarizing plate with a release film. The release film B is peeled off from the single-sided protected polarizing plate with a release film, thereby obtaining a single-sided protected polarizing plate.

[Production of phase difference multilayer]

(Preparation of "alignment layer/first liquid crystal curing layer")

Prepare an alignment layer formed on the substrate film and a λ/4 phase difference layer (first liquid crystal curing layer) which is a layer formed by curing a nematic liquid crystal compound. In addition, the total thickness of the "alignment layer/first liquid crystal curing layer" is 2μm.

(Production of "alignment layer/second liquid crystal curing layer")

10.0 parts by mass of polyethylene glycol di(meth)acrylate (manufactured by Shin-Nakamura Chemical Co., Ltd., A-600), 10.0 parts by mass of trihydroxymethylpropane triacrylate (manufactured by Shin-Nakamura Chemical Co., Ltd., A-TMPT), 10.0 parts by mass of 1,6-hexanediol di(meth)acrylate (manufactured by Shin-Nakamura Chemical Co., Ltd., A-HD-N), and 1.50 parts by mass of IRGACURE 907 (manufactured by BASF, Irg-907) as a photopolymerization initiator were dissolved in 70.0 parts by mass of methyl ethyl ketone as a solvent to prepare a coating liquid for forming an alignment layer as a composition for forming an alignment layer.

Prepare a 20μm thick strip of cyclic olefin resin (COP) film (produced by ZEON Co., Ltd., Japan) as a substrate film, and apply the coating liquid for forming the alignment layer on one side of the substrate film using a rod coater.

The coated layer was heat treated at 80°C for 60 seconds and then irradiated with ultraviolet rays (UVB) of 220 mJ/cm ² to polymerize and cure the alignment layer forming composition, thereby forming an alignment layer with a thickness of 2.3 μm on the base film.

20.0 parts by mass of a photopolymerizable nematic liquid crystal compound (RMM28B manufactured by Merck) and 1.0 parts by mass of IRGACURE 907 (Irg-907 manufactured by BASF) as a photopolymerization initiator were dissolved in 80.0 parts by mass of propylene glycol monomethyl ether acetate as a solvent to prepare a coating liquid for forming a phase difference layer as a composition for forming a phase difference layer.

The coating liquid for forming the phase difference layer was applied on the alignment layer obtained previously, and the coating layer was heat treated at 80°C for 60 seconds. Then, it was irradiated with ultraviolet rays (UVB) of 220mJ/ ^cm2 to polymerize and cure the composition for forming the phase difference layer, thereby forming a phase difference layer (second liquid crystal curing layer) with a thickness of 0.7μm on the alignment layer. In this way, a "alignment layer/second liquid crystal curing layer" with a total thickness of 3μm was obtained on the substrate film.

(Production of phase difference multilayer)

The "alignment layer/first liquid crystal curing layer" laminated on the substrate film and the "alignment layer/second liquid crystal curing layer" laminated on the substrate film are laminated by means of a UV curable adhesive (thickness 1μm) so that the individual liquid crystal curing layer surfaces (surfaces on the opposite side of the substrate film) become the laminating surfaces. Then, the UV curable adhesive is cured by irradiating with ultraviolet rays, and a phase difference multilayer having two liquid crystal curing layers of the first liquid crystal curing layer and the second liquid crystal curing layer is produced.

[Preparation of photoselective absorptive adhesive layer]

(Preparation of acrylic resin (A-1))

A mixed solution of 86.4 parts of ethyl acetate, 61.9 parts of butyl acrylate and 1.9 parts of 2-hydroxyethyl acrylate as a solvent was added to a reaction vessel equipped with a cooling tube, a nitrogen inlet tube, a thermometer and a stirrer, and the internal temperature was raised to 60°C while replacing the air in the apparatus with nitrogen to make it oxygen-free. Then, a total amount of a solution prepared by dissolving 0.4 parts of azobisisobutyronitrile (polymerization initiator) in 10 parts of ethyl acetate was added. The resulting mixture was kept at 60°C for 1 hour, and then, while the internal temperature was kept at 50 to 70°C, ethyl acetate was continuously added to the reaction vessel at an addition rate of 17.3 parts/hr. The addition of ethyl acetate was stopped when the acrylic resin concentration reached 35%, and the temperature was kept at that temperature until 12 hours had passed since the start of the addition of ethyl acetate. Finally, ethyl acetate was added to adjust the acrylic resin concentration to 20%, and an ethyl acetate solution of acrylic resin was prepared. The weight average molecular weight Mw of the obtained acrylic resin converted to polystyrene obtained by GPC was 600,000, and Mw/Mn was 7.0. It was used as acrylic resin (A-1). The glass transition temperature obtained by DSC was -52.9°C.

(Preparation of adhesive layer (1))

In an ethyl acetate solution of an acrylic resin (A-1) (resin concentration: 20%), 0.5 parts of a crosslinking agent (CORONATE L, solid content 75%: TOSOH), 0.5 parts of a silane compound (SKM-403, Shin-Etsu Chemical Co., Ltd.), and 2.5 parts of a compound represented by the formula (aa2) described as a light selective absorbing compound (2) in Synthesis Example 2 described in paragraph [0142] of Japanese Patent Publication No. 2019-007001 (light selective absorbing agent) were mixed with respect to 100 parts of the solid content of the solution, and 2-butanone was further added in such a manner that the solid content concentration became 14%, thereby obtaining an adhesive composition (1). The amount of the crosslinking agent (CORONATE L) blended is the mass fraction in terms of the active ingredient.

The adhesive composition (1) prepared above was applied to the release-treated surface of a polyethylene terephthalate film (manufactured by LINTEC, SP-PLR382050, hereinafter referred to as "separator") using an applicator so that the adhesive layer thickness after drying would be 17 μm, and dried at 100°C for 1 minute to prepare an adhesive layer. The obtained adhesive layer was referred to as an adhesive layer (1). Table 1 shows the content of the light selective absorber per unit area of the adhesive layer (1).

(Preparation of adhesive layer (2))

The amount of light selective absorber added was set to 3.7 parts, and the adhesive layer (2) was prepared in the same manner as the adhesive layer (1). Table 1 shows the content of light selective absorber per unit area of the adhesive layer (2).

(Preparation of adhesive layer (3))

The amount of light selective absorber added was set to 5.4 parts, and the adhesive layer (3) was prepared in the same manner as the adhesive layer (1). Table 1 shows the content of light selective absorber per unit area of the adhesive layer (3).

[Preparation of the second adhesive layer]

0.5 parts of a crosslinking agent (CORONATE L, solid content 75%: manufactured by TOSOH) and 0.5 parts of a silane compound (manufactured by Shin-Etsu Chemical Co., Ltd.: KBM-403) were mixed into the ethyl acetate solution of the acrylic resin (A-1) (resin concentration: 20%), and 2-butanone was further added so that the solid content concentration became 14%, thereby obtaining an adhesive composition. The amount of the crosslinking agent (CORONATE L) blended is the mass fraction in terms of the active ingredient.

The adhesive composition was applied to the release treatment surface of the separator used in the preparation of the light selective absorption adhesive layer using an applicator so that the adhesive layer thickness after drying would be 5μm, and dried at 100℃ for 1 minute to prepare the second adhesive layer.

[Fabrication of optical layered structures]

(Examples 1 and 3)

The second adhesive layer is bonded to the polarizer side of the manufactured single-sided protected polarizing plate, and the separator is peeled off. The exposed surface of the substrate film of the manufactured phase difference layer body peeled off from the first liquid crystal curing layer is bonded to the surface of the second adhesive layer from which the separator is peeled off. Then, the substrate film on the second liquid crystal curing layer side is peeled off, and the adhesive layer listed in Table 1 is attached to the surface of the alignment layer on the second liquid crystal curing layer side as a light selective absorption adhesive layer, thereby obtaining an optical laminate having a layer structure of "protective film A/water-based adhesive/polarizer/second adhesive layer/alignment layer/first liquid crystal curing layer/second liquid crystal curing layer/alignment layer/light selective absorption adhesive layer/separator". In the optical laminate, the middle layer has a layer structure of "second adhesive layer/alignment layer/first liquid crystal curing layer/second liquid crystal curing layer/alignment layer", and the total thickness is 11μm.

In the above, the second adhesive layer was prepared by applying with an applicator so that the thickness of the adhesive layer became 5μm, and drying at 100℃ for 1 minute. The total thickness of the "alignment layer/first liquid crystal curing layer" is 2μm. The total thickness of the "alignment layer/second liquid crystal curing layer" is 3μm.

The thickness of UV curable adhesive is 1μm.

(Examples 2, 4, and Comparative Example 1)

The second adhesive layer is bonded to the polarizer side of the manufactured single-sided protective polarizing plate, and the separator is peeled off. The adhesive layer listed in Table 1 is bonded to the surface of the second adhesive layer from which the separator is peeled off as a light selective absorption adhesive layer, and an optical laminate consisting of "protective film A/water-based adhesive/polarizer/second adhesive layer/light selective absorption adhesive layer/separator" is obtained. In the optical laminate, the middle layer is composed of the "second adhesive layer" and its thickness is 5μm.

In the above, the adhesive layer was applied using an applicator so that the thickness of the adhesive layer became 5μm, and dried at 100℃ for 1 minute to prepare the second adhesive layer.

[Absorbance measurement of adhesive layer]

Adhesive layers (1) to (3) were bonded to glass, and after the separator was peeled off, a cycloolefin polymer (COP) film (ZF-14, manufactured by ZEON Co., Ltd., Japan) was bonded to the adhesive layer to prepare a laminate for adhesive layer evaluation. The laminate for adhesive layer evaluation was placed in a spectrophotometer UV-2450 (manufactured by Shimadzu Corporation) and the absorbance was measured in a wavelength range of 300 to 800 nm in 1 nm steps by a double beam method. The absorbance of the prepared adhesive layer at a wavelength of 410 nm is shown in Table 1. In addition, the absorbance of the glass and the absorbance of the COP film at a wavelength of 410 nm were both 0.

[Determination of weight average molecular weight (Mw)]

The weight average molecular weight (Mw) of the acrylic resin (A-1) is the number average molecular weight (Mn) converted to polystyrene, and tetrahydrofuran is used as the mobile phase, and it is determined by the following size separation chromatography (SEC). The (meth)acrylic polymer to be measured is dissolved in tetrahydrofuran at a concentration of about 0.05 mass %, and 10 μL is injected into SEC.

The mobile phase flows at a flow rate of 1.0 mL/min. The column used is PLgel MIXED-B (manufactured by Polymer Laboratories). The detector used is a UV-VIS detector (trade name: Agilent GPC).

[Determination of Boron Content]

Dissolve 0.2g of polarizer in 200g of 1.9wt% mannitol aqueous solution. Titrate the resulting aqueous solution with 1mol/L NaOH aqueous solution, compare the amount of NaOH required for neutralization with the calibration curve, and calculate the boron content of the polarizer.

[Wet and heat resistance test and color fading observation]

After peeling off the separators of the optical laminates obtained in Examples 1 to 4 and Comparative Example 1 and attaching them to an alkali-free glass plate, they were placed in an environment of 65°C and 90%RH for 500 hours.

Afterwards, a polarizing plate that forms a cross-polarizer relationship is attached to the alkali-free glass surface opposite to the optical laminate under test, and the image is observed and saved using an optical microscope. The optical microscope used is "VHX-500" manufactured by Keyence Co., Ltd. FIG4 shows an example of an image observed using an optical microscope. In FIG4, if the image is observed from the end 50 of the optical laminate toward the inner side along the straight line indicated by the arrow (a straight line extending vertically from the end 50), it can be seen that there is a discolored area 51 and an area that has not discolored (non-discolored area) 52.

[Measurement of color fading by image processing]

The image observed under the microscope was converted into black and white 256 levels (0 to 255) using the image analysis software "ImageJ (free software)". The method of converting into black and white 256 levels (0 to 255) uses the method of taking the average of the RGB values. Figure 5 shows an example of the converted data. Relative to the end 50 of the optical integration body, the middle point (middle of the discolored layer) between the discolored area 51 and the non-discolored area 52 in the level curve (profile) in the vertical direction (arrow in Figure 4) is taken as the discolored end of the optical integration body (Figure 5), and the distance (μm) from the end 50 of the optical integration body to the discolored end is measured as the discolored distance. The discolored distance of the optical integration body is shown in Table 1. The smaller the fading distance, the narrower the fading range, and the better the moisture and heat resistance.

[Table 1]

10: Polarizer

11: Protective film

20: Photoselective absorbent adhesive layer

100: Optical multilayers

300: Middle layer

Claims (9)

An optical laminate having a polarizer, a light selective absorbing adhesive layer, and an intermediate layer laminated between the polarizer and the light selective absorbing adhesive layer and in contact with the polarizer and the light selective absorbing adhesive layer, wherein the intermediate layer has only one layer or a plurality of layers selected from the group consisting of a liquid crystal curing layer, an alignment layer, and a bonding layer, the polarizer is iodine-adsorbed and aligned and has a boron content of 5.0 mass % or less, the light selective absorbing adhesive layer contains a light selective absorber and the content of the light selective absorber per unit area is 0.01 g/m2 or more and 0.47 g/m2 or ^less . ² or less, and the absorbance of the aforementioned light selective absorption adhesive layer at a wavelength of 410nm is greater than 0.1 and less than 2.3. The optical multilayer as described in claim 1 further comprises a protective film, wherein the protective film is laminated on the side of the polarizer opposite to the side of the intermediate layer. An optical laminate as described in claim 1 or 2, wherein the light selective absorbing adhesive layer contains 0.1 to 10 parts by mass of the light selective absorber relative to 100 parts by mass of the total resin component contained in the light selective absorbing adhesive layer. An optical multilayer as described in claim 1 or 2, wherein the thickness of the aforementioned light selective absorption adhesive layer is greater than 0.1μm and less than 150μm. The optical multilayer as described in claim 1 or 2, wherein the aforementioned light selective absorber is an organic light selective absorber having a molecular weight of not less than 100 and not more than 3000. An optical multilayer as described in claim 1 or 2, wherein the intermediate layer has a λ/4 phase difference layer belonging to the liquid crystal curing layer. The optical layered body as described in claim 1 or 2 is a polarizing plate for anti-reflection. An image display device includes an image display panel and the optical multilayer body described in claim 7 disposed on the front surface of the image display panel. An image display device as described in claim 8, wherein the image display panel is an organic EL display panel.