TWI912269B - Optical laminate and image display device - Google Patents

Abstract

This invention provides a novel optical laminate capable of suppressing color loss at end portion of polarizer under high temperature and high humidity.

An optical laminate according to the present invention has a polarizer and a light selective absorption pressure-sensitive adhesive layer laminated on and in contact with the polarizer, wherein the polarizer is adsorbed and oriented with iodine, the content of boron in the polarizer is 5.0% by mass or less, and the pressure-sensitive adhesive composition forming the light-selective absorbing pressure-sensitive adhesive layer includes a light-selective absorbing polymer.

Description

Optical laminates and image display devices

This invention relates to optical layers and display devices.

Polarizing plates, made by laminating protective films onto one or both sides of a polarizer, are widely used in image display devices, primarily liquid crystal displays (LCDs) and organic electroluminescent (OLED) displays, especially in recent years as optical components in various mobile devices such as phones, smartphones, and tablets.

Polarizing plates are typically bonded to image display elements (such as liquid crystal units and organic EL display elements) via an adhesive layer (e.g., Japanese Patent Application Publication No. 2010-229321 (Patent Document 1)). Therefore, polarizing plates are sometimes marketed as adhesive-coated polarizing plates with an adhesive layer pre-formed on one side.

Furthermore, mobile machines are often used in extremely harsh environments with high temperature and humidity, requiring polarizers to have high durability. Japanese Patent Application Publication No. 2013-105036 (Patent Document 2) discloses that by increasing the boric acid content in the polarizer to generate a large amount of boric acid crosslinks, the _I3 complex is highly oriented and exists with high stability, thereby suppressing the occurrence of blue light leakage and obtaining a polarizer with excellent durability in low temperature and high humidity.

[Previous Technical Documents]

[Patent Documents]

[Patent Document 1] Japanese Patent Application Publication No. 2010-229321

[Patent Document 2] Japanese Patent Application Publication No. 2013-105036

In polarizing plates, there is a problem of discoloration easily occurring at the ends of the polarizer under high temperature and humidity environments. This problem is particularly pronounced in configurations where a protective film is simply laminated onto a single-sided layer of the polarizer. Although methods to suppress discoloration by increasing the boron content in the polarizer are known, these methods are prone to shrinkage due to heat.

The purpose of this invention is to provide a novel optical laminate that suppresses decolorization at the ends of a polarizer under high temperature and humidity conditions.

This invention provides the optical laminates illustrated below and an image display device using the optical laminates.

[1] An optical laminate comprising a polarizer and a light-selective absorbing adhesive layer laminated in contact with the polarizer, wherein,

The aforementioned polarizer contains oriented iodine and has a boron content of less than 5.0% by mass.

The adhesive composition forming the aforementioned light-selectively absorbing adhesive layer comprises a light-selectively absorbing polymer.

[2] The optical laminate as described in [1] further comprises a protective film deposited on the side of the aforementioned polarizer opposite to the aforementioned light-selective absorbent adhesive layer.

[3] An optical laminate as described in [1] or [2], wherein the aforementioned light-selective absorbing polymer is a resin containing structural units having the structure shown in the following chemical formula (1) and having a glass transition temperature of 40°C or less:

>N-C=C-C=C< (1) [However, not all of the one N atom and four C atoms constituting chemical formula (1) are part or all of an aromatic heterocycle].

[4] In the optical laminate as described in [3], the content of the structural unit having the structure shown by the aforementioned chemical formula (1) is 0.01 parts by mass or more and 50 parts by mass or less per 100 parts by mass of all structural units.

[5] An optical laminate as described in any of claims [1] to [4], wherein the weight-average molecular weight of the aforementioned light-selective absorbing polymer is 300,000 or more.

[6] An optical laminate as described in any one of [1] to [5], wherein the aforementioned adhesive composition is free of a light-selective absorber, or the content of a light-selective absorber relative to 100 parts by weight of the total resin composition is 0.1 parts by weight or less.

[7] The optical laminate as described in any of [1] to [6] further comprises a λ/4 phasor layer, which is laminated on the side opposite to the aforementioned light-selective absorbent adhesive layer to the aforementioned polarizer.

[8] An optical laminate as described in any of [1] to [7], which is an anti-reflective polarizing plate.

[9] An image display device includes an image display panel and an optical laminate as described in [8] disposed in front of the image display panel.

[10] The image display device as described in [9] is an organic EL display device.

According to the present invention, an optical laminate that suppresses decolorization at the end of a polarizer in high-temperature and high-humidity environments, and an image display device containing the optical laminate, are provided.

10: Polarizing film

11: Protective Film

20: Light-selective absorbent adhesive layer

30: First phase difference layer

31: Second phase difference layer

32: Second adhesive layer

33: Next layer

50: End of optical laminate

51: Bleached Area

52: Non-bleaching areas

100: Optical Layers

200: Optical Layers

300: Phase Difference Integrator

Figure 1 is a schematic cross-sectional view showing an example of the optical laminate of the present invention.

Figure 2 is a schematic cross-sectional view showing another example of the optical laminate of the present invention.

Figure 3 shows an example of an image observed using an optical microscope.

Figure 4 shows an example of converting an observed image into 256 grayscale data.

The following description, with reference to the accompanying drawings, illustrates various embodiments of the invention; however, the invention is not limited to these embodiments. In all the following drawings, the constituent elements are shown with appropriately adjusted scales to facilitate understanding; the scales of the constituent elements shown in the drawings may not be identical to the scales of the actual constituent elements.

<Optical Laminations>

The optical laminate of this invention comprises a polarizer and a light-selective absorbing adhesive layer laminated in contact with the aforementioned polarizer. An example of the layer configuration of the optical laminate of this invention is shown in Figures 1 and 2.

Figure 1 is a schematic cross-sectional view of an example of the optical laminate of the present invention. The optical laminate 100 shown in Figure 1 sequentially comprises a protective film 11, a polarizer 10, and a light-selective absorbent adhesive layer 20.

Figure 2 is a schematic cross-sectional view of an example of the optical laminate of the present invention. The optical laminate 200 shown in Figure 2 comprises the optical laminate 100 shown in Figure 1, and a phase retardation laminate 300 laminated on the light-selective absorber adhesive layer 20 side of the optical laminate 100. The phase retardation laminate 300 sequentially comprises a first phase retardation layer 30, an adhesive layer 33, a second phase retardation layer 31, and a second adhesive layer 32 from the light-selective absorber adhesive layer 20 side of the optical laminate 100.

The thickness of optical laminates of 100 and 200 μm varies depending on the required function and application of the optical laminate, and is therefore not particularly limited. For example, it can be 5 μm to 200 μm, 10 μm to 150 μm, or even less than 120 μm.

The light-selective absorbing adhesive layer comprises a light-selective absorbing polymer. The optical multilayer system of this invention possesses light-selective absorption properties at least in the light-selective absorbing adhesive layer, thereby making the entire optical multilayer possess light-selective absorption properties. Light-selective absorption refers to the property of readily absorbing light of a specific wavelength, exhibiting at least one absorption maximum in the ultraviolet to visible light region. For example, when the light-selective absorbing adhesive layer has ultraviolet absorption capability, the optical multilayer system disposed on an image display element has the function of protecting the image display element from ultraviolet radiation.

The optical laminate of this invention can also include layers with light-selective absorption properties in addition to the light-selective absorbent adhesive layer. Other layers include, for example, the protective film 11. In this invention, the light-selective absorbent adhesive layer possesses light-selective absorption properties, contributing to the overall light-selective absorption performance of the optical laminate. This increases the design freedom for the light-selective absorption properties of other layers. For example, regarding the protective film 11, there are cases where its thickness must be designed to improve light-selective absorption performance; however, due to the high degree of design freedom for light-selective absorption properties, the protective film 11 can be easily made into a thin film.

The light-selective absorbing polymer in the light-selective absorbing adhesive layer possesses light-selective absorption properties. To enhance these properties, the adhesive layer can be configured to contain no light-selective absorber or have a reduced light-selective absorber content, thereby suppressing decolorization at the ends of the polarizer under high temperature and humidity conditions.

The inventors of this case have observed that there is a correlation between the content of light-selective absorbers in the adhesive layer and the degree of decolorization at the end of the polarizer under high temperature and humidity. Based on this observation, it is generally accepted that when using lower molecular weight light-selective absorbers, under high temperature and humidity, the light-selective absorbers in the adhesive layer tend to migrate to the polarizer side, and this migration is one of the important reasons for decolorization. The inventors of this invention conducted further active research and discovered that when the adhesive layer is endowed with light-selective absorption properties not by adding light-selective absorbers, but by containing a light-selective absorbing polymer, decolorization at the ends of the polarizer under high temperature and humidity can be suppressed, thus completing this invention. It is generally believed that this is because the larger molecular weight of the light-selective absorbing polymer inhibits migration to the polarizer, thereby suppressing decolorization at the ends of the polarizer.

[Polarizing film]

A polarizer has the property of absorbing linearly polarized light with a vibration plane parallel to its absorption axis and allowing linearly 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 laminate of this invention has iodine adsorbed and oriented, and the boron content is 5.0% by mass or less.

By using a boron content of 5.0% by mass or less, preferably 4.5% by mass or less, shrinkage caused by heating can be suppressed. A boron content of 0.5% by mass or more is preferred, and 1% by mass or more is even better. In the polarizer 10, the lower the boron content, the easier it is for decolorization to occur at the ends of the polarizer under high temperature and humidity. It is generally believed that since boron in the polarizer 10 increases the crosslinking degree of the polarizer 10, it helps to stably retain iodine in the polarizer 10. Therefore, if the boron content is lower, it becomes more difficult to stably retain iodine, and decolorization becomes more likely. In this invention, even with a boron content of 5.0% by mass or less, decolorization under high temperature and humidity can be suppressed in the polarizer 10.

Polarizing films 10 may include: extended films or layers adsorbed with anisotropic dichroic pigments, cured materials containing polymerizable liquid crystal compounds, and cured liquid crystal layers containing dichroic pigments. Dichroic pigments refer to pigments whose absorbance along the long axis and along the short axis of the molecule has different properties; iodine is suitable as a pigment.

Polarizing films are extended films that adsorb anisotropic pigments. They are typically manufactured through the following steps: uniaxially extending a polyvinyl alcohol (PVA) resin film; dyeing the PVA resin film with a bichromatic pigment such as iodine to adsorb the pigment; treating the PVA resin film with the adsorbed pigment using a boric acid aqueous solution; and washing with water after boric acid treatment.

The thickness of polarizers is typically below 30 μm, preferably below 15 μm, more preferably below 13 μm, even more preferably below 10 μm, and ideally below 8 μm. The thickness of polarizers is typically above 2 μm, preferably above 3 μm, and for example, above 5 μm.

Polyvinyl alcohol (PVA) resins are obtained by saponifying polyvinyl acetate (PVC) resins. Besides using polyvinyl acetate homopolymers, copolymers of vinyl acetate with other monomers that can copolymerize with vinyl acetate can also be used as PVC resins. Other monomers that can copolymerize with vinyl acetate include, for example, unsaturated carboxylic acid compounds, olefinic compounds, vinyl ether compounds, unsaturated monoxide compounds, and ammonium-containing (meth)acrylamide compounds.

The degree of saponification of polyvinyl alcohol (PVA) resins is typically between 85 and 100 mol%, preferably above 98 mol. PVA resins can be modified, and aldehyde-modified forms such as polyethylene formaldehyde and polyethylene acetal can be used. The degree of polymerization of PVA resins is typically between 1000 and 10000, preferably between 1500 and 5000.

Polarizing films are extension layers that adsorb anisotropic pigments and are typically manufactured through the following steps: applying a coating solution containing the aforementioned polyvinyl alcohol resin onto a substrate film; uniaxially extending the obtained laminated film; dyeing the polyvinyl alcohol resin layer of the uniaxially extended laminated film with a dichroic pigment such as iodine to adsorb the dichroic pigment and form a polarizing film; treating the film adsorbed with the dichroic pigment with a boric acid aqueous solution; and washing with water after treatment with the boric acid aqueous solution. The substrate film used to form the polarizing film can also be used as a protective film 11. The substrate film can be peeled off from the polarizing film if necessary. The material and thickness of the substrate film can be the same as those of the protective film 11, which will be described later.

[Protective Film]

The protective film 11 may be a coating or film made of an optically transparent thermoplastic resin. The aforementioned optically transparent thermoplastic resin includes, for example: cyclic polyolefin resins; acetate cellulose resins including cellulose triacetate and cellulose diacetate; polyester resins including polyethylene terephthalate, polyethylene naphthalate, and polybutylene terephthalate; polycarbonate resins; (meth)acrylic resins; polypropylene resins, or mixtures of one or more of these. The protective film 11 may contain a light-selective absorber, as described later. Furthermore, since the light-selective absorber contained in the protective film 11 is contained within the protective film 11, it is less likely to migrate 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 both sides of the protective film 11. By providing the hard coating layer, the protective film 11 can be made with improved hardness and scratch resistance. The hard coating layer can be, for example, a hardened layer of acrylic resin, polysiloxane resin, polyester resin, amine resin, amide resin, epoxy resin, etc. To improve strength, the hard coating layer may also contain additives. Additives are not limited and can include inorganic microparticles, organic microparticles, or mixtures thereof. The hard coating layer can be, for example, a hardened layer of a UV-curing resin. UV-curing resins include, for example, acrylic resins, polysiloxane resins, polyester resins, amine ester resins, amide resins, and epoxy resins.

The thickness of the protective film 11 is typically between 1 μm and 100 μm. From the perspectives of strength and operability, a thickness between 5 μm and 80 μm is preferred, between 8 μm and 60 μm is even better, and between 12 μm and 45 μm is still the best.

The resin film protecting the film 11 is bonded to the polarizer 10, for example, through an adhesive layer. The adhesive used to form the adhesive layer can be, for example, a water-based adhesive, an active energy radiation-curing adhesive, or a thermosetting adhesive; preferably, a water-based adhesive or an active energy radiation-curing adhesive is used. The two opposing surfaces bonded through the adhesive layer can be pre-treated with corona treatment, plasma treatment, flame treatment, etc., and may also have a primer layer.

[Light-selective absorbent adhesive layer]

The light-selective absorbent adhesive layer 20 is formed by dissolving or dispersing an adhesive composition containing a light-selective absorbent polymer in an organic solvent to create a thinner, applying the thinner to a substrate, and then drying it. Suitable substrates include plastic films; specifically, release films that have undergone release treatment can be cited. Examples of release films include those made of resins such as polyethylene terephthalate, polybutylene terephthalate, polycarbonate, and polyarylate, on one side of which a polysiloxane treatment has been applied.

The thickness of the light-selective absorber adhesive layer is, for example, 0.1 μm to 150 μm. When laminated with an image display panel, the thickness of the light-selective absorber adhesive layer is typically 8 μm to 60 μm, and from a thinning perspective, preferably 30 μm or less, more preferably 25 μm or less, and particularly preferably 20 μm or less. When laminated with other optical films, such as λ/4 retardation layers, the thickness of the light-selective absorber adhesive layer is typically 2 μm to 30 μm, preferably 25 μm or less, more preferably 20 μm or less, and particularly preferably 18 μm or less. It is also preferably 3 μm or more, for example, it can be 10 μm or more, but for further thinning, preferably 10 μm or less, and particularly preferably 7 μm or less.

The light-selective absorbent adhesive layer 20 preferably has an absorbance of 0.1 to 1.6 at a wavelength of 410 nm. This is because, by giving the light-selective absorbent adhesive layer 20 such absorbance, the optical laminate as a whole will exhibit the desired light-selective absorption performance, and the optical laminate as a whole can be easily constructed in a thin form.

The absorbance of light-selective absorbent adhesive layers at a wavelength of 390 nm is typically below 5.0, and can be below 4.5.

The absorbance of light-selective absorbent adhesive layers at a wavelength of 400 nm is typically below 5.0, and can be below 4.5.

The absorbance of the light-selective absorbent adhesive layer at a wavelength of 420 nm is typically below 1.00, preferably below 0.60, and even more preferably below 0.40 and above 0.00.

The absorbance of the light-selective absorbent adhesive layer at a wavelength of 430 nm is typically less than 0.20, preferably less than 0.18, more preferably less than 0.10, and most preferably less than 0.05 and more than 0.00.

The absorbance of the light-selective absorbent adhesive layer at a wavelength of 440 nm is typically less than 0.10, preferably between 0.05 and 0.00. By achieving absorbance within the above range at various wavelengths, ultraviolet light can be sufficiently absorbed, while allowing visible light to pass through directly.

The light-selective absorbent adhesive layer is preferably an adhesive layer satisfying formula (3), and more preferably an adhesive layer satisfying formula (4).

A(405)≧0.5 (3) [In equation (3), A(405) represents the absorbance at a wavelength of 405 nm.]

A(405)/A(440)≧5 (4) [In equation (4), A(405) represents the absorbance at a wavelength of 405 nm, and A(440) represents the absorbance at a wavelength of 440 nm.]

A higher value of A(405) indicates higher absorption at a wavelength of 405 nm. When the value of A(405) is less than 0.5, the absorption at 405 nm is low, and components prone to degradation by light near 400 nm (such as organic EL displays and liquid crystal phase retardation films) are more likely to degrade. A value of A(405) is preferably 0.6 or higher, more preferably 0.8 or higher, and especially preferably 1.0 or higher. While no specific upper limit is specified, it is typically below 10.

The value of A(405)/A(440) represents the magnitude of absorption at wavelength 405 nm relative to the magnitude of absorption at wavelength 440 nm. A larger value indicates more specific absorption in the wavelength region around 405 nm. A value of A(405)/A(440) of 10 or higher is preferred, 30 or higher is even better, 75 or higher is still better, and 100 or higher is exceptionally good.

[Adhesive components]

(Photoselective Absorbing Polymer)

The adhesive composition contains a light-selective absorbing polymer. The light-selective absorbing polymer is a polymer with light-selective absorption properties. Preferably, the light-selective absorbing polymer can absorb light in the wavelength range of 360 nm to 420 nm. The light-selective absorbing polymer contains light-selective absorbing structural units, which have sites with light-selective absorption properties. Preferably, the light-selective absorbing structural units have sites with light-selective absorption properties on the side chains. Examples of sites with light-selective absorption properties include benzophenone groups, benzotriazole groups, and structures shown in the following chemical formula (1).

The light-selective absorbing polymer is preferably a resin (A) containing structural units having the structure shown by the following chemical formula (1) (hereinafter referred to as the "Merocyanine structure") as light-selective absorbing structural units, and having a glass transition temperature of 40°C or below.

>N-C=C-C=C< (1) [However, not all of the one N atom and four C atoms constituting chemical formula (1) are part or all of an aromatic heterocycle].

Resin (A) may have an anthocyanin structure in the main chain or in the side chains. Resin (A) is more preferably a structural unit containing an anthocyanin structure in the side chains.

The glass transition temperature (Tg) of resin (A) is below 40°C, preferably below 20°C, even better below 10°C, and further better below 0°C. Furthermore, the glass transition temperature of resin (A) is typically above -80°C, preferably above -60°C, even better above -50°C, further better above -45°C, and exceptionally good above -30°C. If the glass transition temperature of resin (A) is below 40°C, it is beneficial to improve the adhesion of the light-selective absorbing adhesive layer formed by the adhesive composition containing resin (A) to the adhesive material. Furthermore, if the glass transition temperature of resin (A) is above -80°C, it is beneficial to improve the durability of the light-selective absorbing adhesive layer formed by the adhesive composition containing resin (A) (appearance defects during high-temperature testing: aggregation and damage, etc.). In addition, the glass transition temperature can be measured using a differential scanning calorimeter (DSC).

There are no particular limitations on the structural units with a monotonic structure in the side chains, but they are preferably derived from structural units of compounds having polymeric groups and monotonic structures.

Compounds having polymerizable groups and anthocyanin structures preferably satisfy formula (1-a), and more preferably formula (2-a).

ε(405)≧5 (1-a) [In formula (1-a), ε(405) represents the gram absorptivity of a compound with a polymeric group and anthocyanin structure at a wavelength of 405 nm. The unit of gram absorptivity is L/(g‧cm).]

ε(405)/ε(440)≧20 (2-a) [In formula (2-a), ε(405) represents the gamma absorptivity of a compound with a polymeric group and anthocyanin structure at a wavelength of 405 nm, and ε(440) represents the gamma absorptivity of a compound with a polymeric group and anthocyanin structure at a wavelength of 440 nm.]

For compounds with polymerizable groups and anthocyanin structures, an ε(405) value of 5 L/(g‧cm) or higher is preferred, 10 L/(g‧cm) or higher is even better, 20 L/(g‧cm) or higher is still better, 30 L/(g‧cm) or higher is still even better, and typically below 500 L/(g‧cm). Compounds with higher ε(405) values are more readily absorbed at wavelength 405 nm and are more likely to exhibit the function of suppressing degradation from ultraviolet or short-wavelength visible light.

For compounds with polymerizable groups and anthocyanin structures, a ε(405)/ε(440) value of 20 or higher is preferred, 40 or higher is even better, 70 or higher is still better, and 80 or higher is particularly desirable. Resins containing compounds with high ε(405)/ε(440) values do not impede the color performance of display devices and can suppress light degradation in display devices such as phase retardation films and organic EL elements that absorb light near 405nm.

Structural units with anthocyanin structures in the side chains can be listed, for example, those derived from the structural units of compounds represented by formula (I).

In formula (I), ^R1 , ^R2 , ^R3 , ^R4 and ^R5 represent, respectively, a hydrogen atom, an aliphatic hydrocarbon with 1 to 25 carbon atoms that may have substituents, an aromatic hydrocarbon with 6 to 15 carbon atoms that may have substituents, a heterocyclic group or an vinyl unsaturated group, wherein the _-CH2- contained in the aliphatic hydrocarbon or aromatic hydrocarbon may be substituted by ^-NR1A- , _-SO2- , -CO-, -O- or S-.

^R6 and ^R7 represent, respectively, a hydrogen atom, an alkyl group having 1 to 25 carbon atoms, an electron-withdrawing group, or an ethylene unsaturated group.

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

^R1 and ^R2 can be connected to each other to form a ring structure, ^R2 and ^R3 can be connected to each other to form a ring structure, ^R2 and ^R4 can be connected to each other to form a ring structure, ^R3 and ^R6 can be connected to each other to form a ring structure, ^R5 and ^R7 can be connected to each other to form a ring structure, and ^R6 and ^R7 can be connected to each other to form a ring structure.

However, any one of ^R1 to ^R7 is an vinyl unsaturated group.

The aliphatic hydrocarbons with 1 to 25 carbon atoms represented by ^R1 to ^R5 are preferably listed as follows: methyl, ethyl, n-propyl, isopropyl, n-butyl, tributyl, dibutyl, n-pentyl, isopentyl, n-hexyl, isohexyl, n-octyl, isooctyl, n-nonyl, isonyl, n-decyl, isodel, n-dodecyl, isododecyl, undecyl, lauryl, myristyl, cetyl, stearyl, etc., which are straight-chain or branched-chain alkyl groups with 1 to 25 carbon atoms; cycloalkyl groups with 3 to 25 carbon atoms such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl; cycloalkyl groups with 4 to 25 carbon atoms such as cyclohexylmethyl, etc., preferably alkyl groups with 4 to 25 carbon atoms.

The substituent systems that aliphatic hydrocarbons with carbon numbers of 1 to 25, represented by ^R1 to ^R5, can have include: hydroxyl, cyano, halogen, tanyl, amino, nitro, etc.

Halogen atoms can be listed as follows: fluorine, chlorine, bromine, and iodine.

The aromatic hydrocarbons represented by ^R1 to ^R5 with 6 to 15 carbon atoms can be listed as follows: aryl groups with 6 to 15 carbon atoms, such as phenyl, naphthyl, anthracene, and biphenyl; and aralkyl groups with 7 to 15 carbon atoms, such as benzyl, phenylethyl, naphthylmethyl, and phenyl.

The substituent systems that can exist for aromatic hydrocarbons with 6 to 15 carbon atoms represented by ^R1 to ^R5 include: hydroxyl, cyano, halogen, tanyl, amino, nitro, alkoxy, alkylthio, alkoxycarbonyl, acetyl, acetoxy, -C( ^NR2A ) ^R2B , ^-CONR3AR3B , _-SO2R4A ( ^R2A , ^R2B , ^R3A and ^R3B each independently represent a hydrogen atom or an alkyl group with 1 to 6 carbon atoms, and ^{R4A is} an alkyl ^group with 1 to 6 carbon atoms), etc.

Halogen atoms can be listed as follows: fluorine, chlorine, bromine, and iodine.

Alkoxy groups include: methoxy, ethoxy, propoxy, butoxy, pentoxy, hexoxy, octoxy, 2-ethylhexoxy, nonoxy, decoxy, undecoxy, dodecoxy, and other alkoxy groups with 1 to 12 carbon atoms.

Alkylthio groups include: methylthio, ethylthio, propylthio, butylthio, and other alkylthio groups with 1 to 12 carbon atoms.

Examples of acetyl groups include acetyl, propionic, and butyl, which have 2 to 13 carbon atoms.

Acryloyloxy groups include: methyl carbonyloxy, ethyl carbonyloxy, n-propyl carbonyloxy, isopropyl carbonyloxy, n-butyl carbonyloxy, dibutyl carbonyloxy, tributyl carbonyloxy, pentyl carbonyloxy, hexyl carbonyloxy, octyl carbonyloxy, and 2-ethylhexyl carbonyloxy, which have 2 to 13 carbon atoms.

Alkoxycarbonyl groups include: methoxycarbonyl, ethoxycarbonyl, propoxycarbonyl, butoxycarbonyl, pentoxycarbonyl, hexoxycarbonyl, octoxycarbonyl, 2-ethylhexyloxycarbonyl, nonoxycarbonyl, decoxycarbonyl, undecyloxycarbonyl, dodecyloxycarbonyl, and other alkoxycarbonyl groups with 2 to 13 carbon atoms.

-CONR ^3A R ^3B can include: aminocarbonyl, methylaminocarbonyl, dimethylaminocarbonyl, ethylaminocarbonyl, methylmethylaminocarbonyl, etc.

-C(NR ^2A )R ^2B can include: methylimino, dimethylimino, methylethylimino, etc.

_-SO₂R₄A can ^include : methylsulfonyl, ethylsulfonyl, etc.

Examples of alkyl groups with 1 to 6 carbon atoms represented by R ^1A and R ^1B include: methyl, ethyl, n-propyl, isopropyl, n-butyl, tributyl, dibutyl, etc.

The heterocyclic groups represented by ^R1 to ^R5 can be listed as follows: pyrrolidine cyclic group, pyrrololin cyclic group, imidazoidine cyclic group, imidazoline cyclic group, etc. Azoline cyclic, thiazoline cyclic, piperidine cyclic, morpholine cyclic, piperidine Cycloyl, indole cycloyl, isoindole cycloyl, quinoline cycloyl, thiophene cycloyl, pyrrole cycloyl, thiazoline cycloyl, and furan cycloyl, etc., are aliphatic heterocyclic groups with 4 to 20 carbon atoms or aromatic heterocyclic groups with 3 to 20 carbon atoms.

Alkyl groups with 1 to 25 carbon atoms represented by ^R6 and ^R7 include: methyl, ethyl, n-propyl, isopropyl, n-butyl, tributyl, dibutyl, n-pentyl, isopentyl, n-hexyl, isohexyl, n-octyl, isooctyl, n-nonyl, isonyl, n-decyl, isodecyl, n-dodecyl, isododecyl, undecyl, lauryl, myristyl, cetyl, stearyl, etc., which are straight-chain or branched alkyl groups with 1 to 25 carbon atoms.

Examples of electron-withdrawing groups represented by ^R6 and ^R7 include: cyano, nitro, halogen, alkyl groups substituted with halogen atoms, and groups represented by formula (I-1).

*-X ¹ -R ¹¹¹ (I-1)[where R ¹¹¹ 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 with an oxygen atom.]

X ¹ represents -CO-* ¹ , -COO-* ¹ , -CS-* ¹ , -CSS-* ¹ , -CSNR ¹¹² -* ¹ , -CONR ¹¹³ -* ¹ , -CNR ¹¹⁴ -* ¹ , or SO ₂ -* ¹ .

R ¹¹² , R ¹¹³ and R ¹¹⁴ represent hydrogen atoms, alkyl groups having 1 to 6 carbon atoms, or phenyl groups, respectively.

* ¹ indicates the location where it is bound to R ¹¹¹ .

* Indicates a bond with a carbon atom.

Halogen atoms can be listed as follows: fluorine, chlorine, bromine, and iodine.

Examples of halogen-substituted alkyl groups include: trifluoromethyl, perfluoroethyl, perfluoropropyl, perfluoroisopropyl, perfluorobutyl, perfluorodibutyl, perfluoroterbutyl, perfluoropentyl, and perfluorohexyl, among others. The number of carbon atoms in halogen-substituted alkyl groups typically ranges from 1 to 25.

The hydrocarbons represented by R ¹¹¹ with carbon numbers from 1 to 25 include: methyl, ethyl, n-propyl, isopropyl, n-butyl, tert-butyl, dibutyl, n-pentyl, isopentyl, n-hexyl, isohexyl, n-octyl, isooctyl, n-nonyl, isonyl, n-decyl, isodel, n-dodecyl, isododecyl, undecyl, lauryl, myristyl, cetyl, stearyl Alkyl groups with 1 to 25 carbon atoms, either straight-chain or branched-chain: cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, etc., cycloalkyl groups with 3 to 25 carbon atoms; cyclopropylmethyl, cyclohexylmethyl, etc., cycloalkylalkyl groups with 4 to 25 carbon atoms; phenyl, naphthyl, anthracene, biphenyl, etc., aryl groups with 6 to 25 carbon atoms; benzyl, phenylethyl, naphthylmethyl, phenyl, etc., aralkyl groups with 7 to 25 carbon atoms.

The alkyl groups with 1 to 6 carbons represented by R ¹¹² , R ¹¹³ , and R ¹¹⁴ are the same as those with 1 to 6 carbons represented by R ^1A .

R ¹¹¹ is preferably an alkyl group with 4 to 25 carbon atoms, and even more preferably an alkyl group with 4 to 12 carbon atoms.

X ¹ is preferably -CO-* ¹ and COO-* ¹ .

It is preferable that the electron-withdrawing groups represented by ^R6 and ^R7 are cyano and the group represented by formula (I-1), respectively, independently.

The ring structure formed by the interbonding of ^R1 and ^R2 is a nitrogen-containing ring structure containing nitrogen atoms bonded to ^R1 and ^R2 . Examples include nitrogen-containing heterocycles with 4 to 10 members. The ring structure formed by the interlinking of ^R1 and ^R2 can be monocyclic or polycyclic. Specifically, examples include: pyrrolidine ring, pyrrololine ring, imidazoidine ring, imidazoline ring, etc. Azoline ring, thiazoline ring, piperidine ring, morpholine ring, piperidine ring Rings, indole rings, isoindole rings, etc. The rings formed by the interbonding ^{of R1} and ^R2 may have substituents, such as alkyl groups having 1 to 12 carbons, including methyl, ethyl, propyl, butyl, isobutyl, etc.; and alkoxy groups having 1 to 12 carbons, such as methoxy, ethoxy, propoxy, butoxy, etc.

The ring structure formed by the interbonding of ^R2 and ^R3 is a nitrogen-containing ring structure containing a nitrogen atom bonded to ^R2 . Examples include nitrogen-containing heterocyclic rings with 4 to 10 members. The ring structure formed by the interconnection of ^R2 and ^R3 can be monocyclic or polycyclic. Specifically, examples include: pyrrolidine rings, pyrrololine rings, imidazoidine rings, and imidazoline rings. Azoline ring, thiazoline ring, piperidine ring, morpholine ring, piperidine ring Rings, indole rings, isoindole rings, and ring structures represented by the following formula (I-3).

In formula (I-3), X represents nitrogen atom, oxygen atom, and sulfur atom.

Ring ^W1 represents a ring composed of nitrogen and X.

The preferred ring ^W1 is a 5-membered or 6-membered ring with nitrogen and X as constituent elements.

The ring structure represented by equation (I-3) can be specifically exemplified by the following rings.

The ring structure formed by the mutual bonding of ^R2 and ^R3 can have substituents, such as alkyl groups having 1 to 12 carbons, including methyl, ethyl, propyl, butyl, isobutyl, etc.; and alkoxy groups having 1 to 12 carbons, such as methoxy, ethoxy, propoxy, butoxy, etc.

The ring structure formed by the mutual bonding of ^R2 and ^R3 is preferably represented by the ring structure shown in the following formula (I-4).

In equation (I-4), ^R11 represents the same meaning as above. m2 represents an integer from 1 to 7.

^R11a , ^R11b , ^R11c and ^R11d are each independently represented by a hydrogen atom or an alkyl group having 1 to 12 carbon atoms.

* Indicates a bond with a carbon atom.

A value of 2 or 3 m2 is preferable, with 2 being even better.

The ring structure formed by the interbonding ^{of R2} and ^R4 can be a nitrogen-containing ring structure with 4 to 10 members, preferably a nitrogen-containing ring structure with 5 to 9 members. The ring structure formed by the interbonding of ^R2 and ^R4 can be a monocyclic or polycyclic ring. These rings can have substituents. Such ring structures include: pyrrole rings, indole rings, pyrimidine rings, and rings described below.

The ring structure formed by the interbonding of ^R2 and ^R4 can have substituents, such as: alkyl groups with 1 to 12 carbons, such as methyl, ethyl, propyl, butyl, and isobutyl; alkoxy groups with 1 to 12 carbons, such as methoxy, ethoxy, propoxy, and butoxy; groups represented by -NR ^{22A and} R ^22B , such as amino, methylamino, and dimethylamino (R ^22A and R ^22B represent hydrogen atoms or alkyl groups with 1 to 6 carbons, respectively); alkylthio groups with 1 to 12 carbons, such as methylthio, ethylthio, propylthio, butylthio, and pentylthio; and heterocyclic groups with 4 to 9 carbons, such as pyrrolidinyl, piperidinyl, and morpholinyl.

The ring structure formed by the interconnection of ^R3 and ^R6 is a ring structure in which ^R3 -C=CC= ^CR6 forms the ring skeleton. Examples include phenyl.

The ring structures formed by the interconnection of ^R5 and ^R7 can be listed as described below. The ring structures formed by the interconnection of ^R5 and ^R7 can have substituents, such as alkyl groups having 1 to 12 carbons, such as methyl, ethyl, propyl, butyl, isobutyl; and alkoxy groups having 1 to 12 carbons, such as methoxy, ethoxy, propoxy, butoxy.

The ring structures formed by the interconnection of ^R6 and ^R7 can be listed in the ring structures described below. The ring structures formed by the interconnection of ^R6 and ^R7 can have substituents ( _R1 to _R16 in the following formulas), such substituents as: alkyl groups having 1 to 12 carbons, such as methyl, ethyl, propyl, butyl, isobutyl; alkoxy groups having 1 to 12 carbons, such as methoxy, ethoxy, propoxy, butoxy; and vinyl unsaturated groups, etc., as described below.

[In the formula, * indicates the location where it bonds with a carbon atom.]

The vinyl unsaturated groups represented by ^R1 to ^R7 can be listed as: vinyl, α-methyl vinyl, acrylonitrile, methacrylonitrile, allyl, styryl, and groups represented by formula (I-2).

*-R ¹¹⁵ -X ² (I-2) [In formula (I-2), X ² represents vinyl, acrylonitrile or methacrylonitrile.]

R ¹¹⁵ represents a divalent aliphatic hydrocarbon with 1 to 18 carbon atoms, wherein the -CH ₂ - contained in the aliphatic hydrocarbon can be replaced by -O-, -CO-, -CS- or NR ^116- .

R ¹¹⁶ represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.

* Indicates a bond with a carbon or nitrogen atom.

The aliphatic hydrocarbons with divalent carbon numbers from 1 to 18 represented by R ¹¹⁵ can be listed as follows: methylene, ethyl, propane-1,3-diyl, propane-1,2-diyl, butane-1,4-diyl, pentane-1,5-diyl, hexane-1,6-diyl, butane-1,3-diyl, 2-methylpropane-1,3-diyl, 2-methylpropane-1,2-diyl, pentane-1,4-diyl, and 2-methylbutane-1,4-diyl, etc., which have alkyldiyl carbon numbers from 1 to 18; preferably cyclopropanediyl, cyclobutanediyl, cyclopentanediyl, cyclohexanediyl, etc., which have cycloalkyldiyl carbon numbers from 3 to 18, and aliphatic hydrocarbons with divalent carbon numbers from 1 to 12.

The alkyl groups with 1 to 6 carbons represented by R ¹¹⁶ can be the same as those with 1 to 6 carbons represented by R ^1A .

The vinyl unsaturated groups represented by ^R1 to ^R7 are preferably vinyl, acrylonitrile, methacrylonitrile, and the group represented by formula (I-2), respectively.

It is preferable that either ^R6 or ^R7 is an electron-withdrawing base.

Preferably, either ^R6 or ^R7 is an vinyl unsaturated group.

The structural unit derived from the compound represented by formula (I) is preferably derived from the structural unit derived from the compound represented by formula (II).

In formula (II), ^R11 , ^R12 , ^R13 , ^R14 and ^R15 represent, respectively, a hydrogen atom, an aliphatic hydrocarbon with 1 to 25 carbon atoms that may have substituents, an aromatic hydrocarbon with 6 to 15 carbon atoms that may have substituents, or a heterocyclic hydrocarbon, wherein the _-CH2- contained in the aliphatic hydrocarbon or aromatic hydrocarbon may be substituted by ^NR11A- , _-SO2- , -CO-, -O- or S-.

^R16 and ^R17 represent, independently, a hydrogen atom, an alkyl group having 1 to 25 carbon atoms, an electron-withdrawing group, or an ethylene unsaturated group.

R ^11A represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.

^R12 and ^R13 can be connected to each other to form a ring structure, and ^R12 and ^R14 can be connected to each other to form a ring structure.

However, either ^R16 or ^R17 is an vinyl unsaturated group.

The aliphatic hydrocarbons with 1 to 25 carbon atoms that may have substituents, represented by R ¹¹ to R ^15, can be the same as the aliphatic hydrocarbons with 1 to 25 carbon atoms that may have substituents, represented by R ¹ .

The aromatic hydrocarbons with 6 to 15 carbon atoms that may have substituents, represented by R ¹¹ to R ¹⁵ , can be the same as those with 6 to 15 carbon atoms that may have substituents, represented by R ¹ .

The heterocycles represented by ^R11 to ^R15 are those that are the same as the heterocycles represented by ^R1 .

The alkyl groups with 1 to 25 carbon atoms represented by R ¹⁶ and R ¹⁷ can be listed as the same as the alkyl groups with 1 to 25 carbon atoms represented by R ⁶ .

The electron-withdrawing groups represented by ^R16 and ^R17 are those that are the same as the electron-withdrawing groups represented by ^R6 .

The alkyl groups with 1 to 6 carbons represented by R ^11A and R ^11B can be listed as the same as the alkyl groups with 1 to 6 carbons represented by R ^1A .

The ring structures formed by interconnecting ^R12 and ^R13 can be the same as those formed by interconnecting ^R2 and ^R3 . The ring structures formed by interconnecting ^R12 and ^R13 are preferably single-ring structures.

The ring structures formed by the interconnection of ^R12 and ^R14 can be listed as those identical to those formed by the interconnection ^{of R2} and ^R4 . A monocyclic ring structure is preferred for the interconnection of ^R12 and ^R14 . Aromatic rings are preferred, with pyrimidine ring structures being ^even more preferred.

^R11 , ^R13 and ^R15 are each preferably aliphatic hydrocarbons having 1 to 25 carbon atoms that can have substituents, more preferably alkyl groups having 1 to 25 carbon atoms that can have substituents, and even more preferably alkyl groups having 1 to 12 carbon atoms that can have substituents.

In particular, R ¹¹ is preferably an aliphatic hydrocarbon with 1 to 10 carbon atoms, more preferably an alkyl group with 1 to 10 carbon atoms, and even more preferably a methyl group.

^R12 and ^R14 are each independently an aliphatic hydrocarbon having 1 to 25 carbon atoms and may have substituents, but it is preferred that ^R12 and ^R14 are linked together to form a ring structure.

^R12 and ^R13 are preferably interconnected to form a ring structure, and even more preferably a ring structure represented by the above formula (I-4). Among the ring structures represented by formula (I-4), the ring structure represented by formula (I-4-1) or the ring structure represented by formula (I-4-2) is particularly preferred, and the ring structure represented by formula (I-4-1) is especially preferred.

Preferably, either ^R16 or ^R17 is an ethylene unsaturated group, and the other is an electron-withdrawing group.

The electron-withdrawing groups represented by R ¹⁶ and R ¹⁷ are preferably cyano, nitro, fluoro, trifluoromethyl, and the group represented by formula (I-1), respectively. Cyano is particularly preferred.

The vinyl unsaturated groups represented by R ¹⁶ and R ¹⁷ are preferably vinyl, acrylonitrile, methacrylonitrile, and the group represented by formula (I-2), respectively. More preferably, it is *-CO-O-(CH ₂ )nX ² [X ² represents vinyl, acrylonitrile or methacrylonitrile, n = an integer from 1 to 10 (preferably an integer from 2 to 6)].

The compound represented by formula (II), in which ^R12 and ^R13 are linked together to form a ring structure, is preferably represented by formula (II-A-1) or formula (II-A-2). The compound represented by formula (II), in which ^R12 and ^R14 are linked together to form a ring structure, is preferably represented by formula (II-B-1).

In equations (II-A-1), (II-A-2), and (II-B-1), ^R11 , ^R14 , ^R15 , ^R16 , and ^R17 represent the same meaning as those mentioned above.

^R11e , ^R11f , ^R11g , ^R11h , ^R11k , ^R11m , and ^R11n each independently represent a hydrogen atom or an alkyl group having 1 to 12 carbon atoms.

R ^11q and R ^11p represent, independently, a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, a group represented by -NR ^22A and R ^22B (R ^22A and R ^22B represent, independently, a hydrogen atom or an alkyl group having 1 to 6 carbon atoms), or a heterocyclic ring.

For example, the compound represented by formula (II) with an electron-withdrawing cyano group can be obtained by reacting the compound represented by formula (I’) with the compound represented by formula (L).

[In the formula, ^R222 represents a divalent linker, and ^X2 represents a polymerizable group.]

The reaction between the compound represented by formula (I’) and the compound represented by formula (L) can be carried out under any conditions generally used in Knoevenagel condensation. For example, it is preferably carried out in the presence of a base or carboxylic anhydride. Examples of bases include: triethylamine, N,N-diisopropylethylamine, pyridine, piperidine, pyrrolidine, proline, N,N-dimethylaminopyridine, imidazole, sodium hydroxide, potassium hydroxide, potassium carbonate, sodium carbonate, sodium bicarbonate, potassium bicarbonate, potassium tert-butanol, sodium tert-butanol, sodium hydroxide, etc. Examples of carboxylic anhydrides include: acetic anhydride, succinic anhydride, phthalic anhydride, maleic anhydride, benzoic anhydride, etc. The amount of alkali used is preferably 0.1 to 10 mol relative to 1 mol of the compound represented by formula (I’). The amount of acetic anhydride used is preferably 0.2 to 5 mol relative to 1 mol of the compound represented by formula (I’).

The reaction between the compound represented by formula (I’) and the compound represented by formula (L) is preferably carried out in an organic solvent. Examples of organic solvents include toluene, acetonitrile, dichloromethane, and chloroform.

The reaction between the compound represented by formula (I’) and the compound represented by formula (L) can be carried out by mixing the compound represented by formula (I’) and the compound represented by formula (L).

The reaction temperature for the compounds represented by formula (I’) and formula (L) is preferably -40 to 130°C, and the reaction time is typically 1 to 24 hours.

The compound represented by formula (I’) can be synthesized, for example, according to the method described in Japanese Patent Application Publication No. 2014-194508.

The compound represented by formula (L) can be obtained, for example, by reacting cyanoacetate with hydroxyalkyl acrylate.

The preferred dosage of cyanoacetate is 0.5 to 3 moles, compared to 1 mole of hydroxyalkyl acrylate.

The reaction of cyanoacetate with hydroxyalkyl acrylate can be carried out using any esterification catalyst commonly used in esterification reactions, but is preferably carried out in the presence of a base and a carbodiimide condensing agent. Examples of bases include: triethylamine, diisopropylethylamine, pyridine, piperidine, pyrrolidine, proline, N,N-dimethylaminopyridine, imidazole, sodium hydroxide, potassium hydroxide, potassium carbonate, sodium carbonate, sodium bicarbonate, potassium bicarbonate, potassium terbutoxide, sodium terbutoxide, sodium hydroxide, etc. Examples of carbodiimide condensers include: N,N-dicyclohexylcarbodiimide, N,N-diisopropylcarbodiimide, and 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride. The preferred amount of alkali used is 0.5 to 5 moles relative to 1 mole of cyanoacetate.

The reaction between cyanoacetate and hydroxyalkyl acrylate is preferably carried out in an organic solvent. Examples of organic solvents include acetonitrile, isopropanol, toluene, chloroform, and dichloromethane.

The reaction between cyanoacetate and hydroxyalkyl acrylate can be carried out by mixing cyanoacetate and hydroxyalkyl acrylate.

The reaction temperature between cyanoacetate and hydroxyalkyl acrylate is preferably -40 to 130°C, and the reaction time is typically 1 to 24 hours.

Compounds possessing polymeric groups and anthocyanin structures can be listed below.

Resin (A) can be a homopolymer of structural units having partial anthocyanin structures on the side chains, or a copolymer of structural units having partial anthocyanin structures on the side chains and other structural units. Copolymers are preferred for resin (A).

Besides structural units with anthocyanin structures in the side chains, resin (A) may contain structural units such as those described in group A below.

Group A: Structural units derived from (meth)acrylates, structural units derived from styrene monomers, structural units derived from vinyl monomers, structural units represented by formula (a), structural units represented by formula (b), and structural units represented by formula (c).

[In the formula, ^Ra1 represents a divalent hydrocarbon.]

^Rb1 and ^Rb2 represent hydrogen atoms or hydrocarbon groups independently, respectively.

R c1 and R c2  represent divalent hydrocarbons independently.

Examples of (meth)acrylates include: 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, stearyl (meth)acrylate, and other linear alkyl esters of (meth)acrylate; isopropyl (meth)acrylate, isobutyl (meth)acrylate, tributyl (meth)acrylate, isoamyl (meth)acrylate, isohexyl (meth)acrylate, and so on. Branched alkyl esters of (meth)acrylic acid, such as 2-ethylhexyl acrylate, isooctyl (meth)acrylate, isononyl (meth)acrylate, isostearyl (meth)acrylate, and isopentyl (meth)acrylate; alkyl esters of (meth)acrylic acid containing an alicyclic skeleton, such as cyclohexyl (meth)acrylate, isocamphenyl (meth)acrylate, corundum (meth)acrylate, dicyclopentyl (meth)acrylate, cyclododecyl (meth)acrylate, methylcyclohexyl (meth)acrylate, trimethylcyclohexyl (meth)acrylate, tributylcyclohexyl (meth)acrylate, and α-ethoxycyclohexyl (meth)acrylate; esters of (meth)acrylic acid containing an aromatic ring skeleton, such as phenyl (meth)acrylate; etc.

Structural units derived from (meth)acrylates can also be listed: alkyl (meth)acrylates containing substituents, where the alkyl group in the alkyl group is replaced by a substituent. Substituents in alkyl (meth)acrylates are groups that replace the hydrogen atom of the alkyl group; specific examples include phenyl, alkoxy, and phenoxy groups. Examples of alkyl (meth)acrylates containing substituents include: 2-methoxyethyl (meth)acrylate, ethoxymethyl (meth)acrylate, phenoxyethyl (meth)acrylate, 2-(2-phenoxyethoxy)ethyl (meth)acrylate, diethylene glycol (meth)acrylate phenoxy ester, poly(ethylene glycol) (meth)acrylate phenoxy ester, etc.

These (meth)acrylates can be used individually or in multiple different forms.

The resin (A) of this invention preferably contains structural units of alkyl methacrylate (a1) derived from the homopolymer with a glass transition temperature (Tg) not reaching 0°C, and structural units of alkyl methacrylate (a2) derived from the homopolymer with a Tg above 0°C. This is advantageous for improving the high-temperature durability of the adhesive layer. The Tg of the homopolymer of alkyl methacrylate can be, for example, values from publications such as POLYMER HANDBOOK (Wiley-Interscience).

Specific examples of (meth)acrylate alkyl esters (a1) include: ethyl acrylate, n-propyl acrylate and isopropyl acrylate, n-butyl acrylate and isobutyl acrylate, n-pentyl acrylate, n-hexyl acrylate and isohexyl acrylate, n-heptyl acrylate, n-octyl acrylate and isooctyl acrylate, 2-ethylhexyl acrylate, n-nonyl acrylate and isononyl acrylate, n-decyl acrylate and isodecyl acrylate, n-dodecyl acrylate, and other (meth)acrylate alkyl esters with an alkyl group having approximately 2 to 12 carbon atoms.

Alkyl (meth)acrylate (a1) can be used alone or in combination with two or more types. From the viewpoint of traceability and reworkability during optical film deposition, n-butyl acrylate, n-octyl acrylate, and 2-ethylhexyl acrylate are preferred.

Alkyl methacrylate (a2) refers to alkyl methacrylates other than alkyl methacrylates (a1). Specific examples of alkyl methacrylates (a2) include: methyl acrylate, cyclohexyl acrylate, isoborneol acrylate, stearyl acrylate, tributyl acrylate, etc.

Alkyl methacrylate (a2) can be used alone or in combination with two or more types. From the perspective of high-temperature durability, alkyl methacrylate (a2) containing methyl acrylate, cyclohexyl acrylate, or isoborneol acrylate is preferred, with methyl acrylate being even more desirable.

Furthermore, structural units derived from (meth)acrylates can be exemplified by those derived from (meth)acrylates possessing polar functional groups.

Examples of (meth)acrylate 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, and 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-Hydroxypropyl (meth)acrylate Hydroxyhexyl ester, 4-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, (methyl) 5-Hydroxyl octyl acrylate, 5-Hydroxyl nonyl acrylate, 6-Hydroxyl hexyl acrylate, 6-Hydroxyl heptaacrylate, 6-Hydroxyl octyl acrylate, 6-Hydroxyl nonyl acrylate, 6-Hydroxyl decyl acrylate, 7-Hydroxyl heptaacrylate, 7-Hydroxyl octyl acrylate, 7-Hydroxyl nonyl acrylate Ester, 7-hydroxydecyl methacrylate, 7-hydroxyundecyl methacrylate, 8-hydroxyoctyl methacrylate, 8-hydroxynonyl methacrylate, 8-hydroxydecyl methacrylate, 8-hydroxyundecyl methacrylate, 8-hydroxyundecyl methacrylate, 8-hydroxydodecyl methacrylate, 9-hydroxynonyl methacrylate, 9-hydroxydecyl methacrylate, 9-hydroxyundecyl methacrylate, 9-hydroxydodecyl methacrylate, 9-hydroxytridecyl methacrylate, 10-hydroxydecyl methacrylate, 10-hydroxyundecyl methacrylate, 10-hydroxydodecyl methacrylate, 10-hydroxytridecyl methacrylate, 10-hydroxytetradecyl methacrylate, 1 Alkyl methacrylates containing the hydroxyl group, such as 1-hydroxyundecyl ester, 11-hydroxydodecyl (meth)acrylate, 11-hydroxytetrazyl (meth)acrylate, 11-hydroxytetradecyl (meth)acrylate, 11-hydroxypentadecanyl (meth)acrylate, 12-hydroxydodecyl (meth)acrylate, 12-hydroxytetrazyl (meth)acrylate, 12-hydroxytetradecyl (meth)acrylate, 12-hydroxytetradecyl (meth)acrylate, 13-hydroxypentadecanyl (meth)acrylate, 13-hydroxytetradecyl (meth)acrylate, 13-hydroxytetradecyl (meth)acrylate, 13-hydroxytetradecyl (meth)acrylate, 13-hydroxytetradecyl (meth)acrylate, 13-hydroxytetradecyl (meth)acrylate, 14-hydroxytetradecyl (meth)acrylate, 14-hydroxytetradecyl (meth)acrylate, 15-hydroxytetradecyl (meth)acrylate, and 15-hydroxyheptadecyl (meth)acrylate.

Styrene monomers include styrene; alkylstyrene such as methylstyrene, dimethylstyrene, trimethylstyrene, ethylstyrene, diethylstyrene, triethylstyrene, propylstyrene, butylstyrene, hexylstyrene, heptylstyrene, and octylstyrene; halogenated styrene such as fluorostyrene, chlorostyrene, bromostyrene, dibromostyrene, and iodostyrene; nitrostyrene; acetyrene; methoxystyrene; and divinylbenzene.

Vinyl monomers include: vinyl acetate, vinyl propionate, vinyl butyrate, vinyl 2-ethylhexanoate, vinyl laurate, and other fatty acid vinyl esters; vinyl chloride, vinyl bromide, and other halogenated vinyl groups; vinylidene chloride and other halogenated vinyl groups; vinylpyridine, vinylpyrrolidone, vinyl sulfadiazine, and other nitrogen-containing heteroaromatic vinyl groups; butadiene, isoprene, chloroprene, and other conjugated dienes; and acrylonitrile, methacrylonitrile, and other unsaturated nitrile groups.

Compounds with structural units represented by formula (a) can be synthesized, for example, by the reaction of diisocyanate compounds with polyols.

Compounds with the structural unit represented by formula (b) can be synthesized, for example, by the reaction of halogenated silanes or silanes containing hydroxyl groups.

Compounds with structural units represented by formula (c) can be synthesized, for example, by the reaction of polycarboxylic acids and polyols.

The structural units selected from the structural units described in Group A are preferably structural units derived from (meth)acrylates. Structural units derived from (meth)acrylates are preferably alkyl (meth)acrylates and alkyl (meth)acrylates containing hydroxyl groups.

The resin (A) of this invention may further contain other structural units (sometimes referred to as structural units (aa)). Specifically, these may include: structural units derived from (meth)acrylamide monomers, structural units derived from monomers containing carboxyl groups, structural units derived from monomers containing heterocyclic groups, and structural units derived from monomers containing substituted or unsubstituted amine groups, etc.

(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. Acrylamide, N-isopropyl(meth)acrylamide, N-(3-dimethylaminopropyl)(meth)acrylamide, N-(1,1-dimethyl-3-sideoxybutyl)(meth)acrylamide, N-[2-(2-sideoxy-1-imidazolidine)ethyl](meth)acrylamide, 2-acrylamide amino-2-methyl-1-propanesulfonic acid, N-(methoxymethyl)acrylamide, N-(ethoxymethyl)(meth)acrylamide, N-(propoxy)acrylamide Methyl (methyl)acrylamide, N-(1-methylethoxymethyl)acrylamide, N-(1-methylpropoxymethyl)acrylamide, N-(2-methylpropoxymethyl)acrylamide, N-(butoxymethyl)acrylamide, N-(1,1-dimethylethoxymethyl)acrylamide, N-(2-methoxyethyl)acrylamide, N-(2-ethoxyethyl)acrylamide The formulations include N-(2-propoxyethyl)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, and N-[2-(1,1-dimethylethoxy)ethyl](methyl)acrylamide. Among these, N-(methoxymethyl)acrylamide, N-(ethoxymethyl)acrylamide, N-(propoxymethyl)acrylamide, N-(butoxymethyl)acrylamide, and N-(2-methylpropoxymethyl)acrylamide are preferred.

Monomers containing a carboxyl group include: (meth)acrylic acid, carboxyalkyl esters of (meth)acrylic acid [e.g., carboxyethyl ester of (meth)acrylic acid, carboxypentyl ester of (meth)acrylic acid], maleic acid, maleic anhydride, fumaric acid, crotonic acid, etc., with acrylic acid being preferred.

Monomers containing heterocyclic groups include: acrylamide, vinylcaprolactone, N-vinyl-2-pyrrolidone, vinylpyridine, tetrahydrofuran acrylate, caprolactone-modified tetrahydrofuran acrylate, 3,4-epoxycyclohexylmethyl methacrylate, glycidyl methacrylate, 2,5-dihydrofuran, etc.

Monomer systems with substituted or unsubstituted amino groups include: aminoethyl (meth)acrylate, N,N-dimethylaminoethyl (meth)acrylate, and dimethylaminopropyl (meth)acrylate.

As a structural unit having an anthocyanin structure and a structural unit other than those selected from group A (aa), it is preferably a monomer having a carboxyl group.

Of the total number of structural units in resin (A) per 100 parts by mass, the content of structural units with anthocyanin structures on the side chains is preferably 0.01 to 50 parts by mass, more preferably 0.1 to 20 parts by mass, and even more preferably 0.5 to 10 parts by mass.

For every 100 parts by weight of all structural units of resin (A), the content of at least one structural unit selected from group A is preferably 50 parts by weight or more, and more preferably 60 to 99.99 parts by weight.

When resin (A) contains structural units (aa), the amount of structural unit (aa) is preferably 20 parts by mass or less, more preferably 0.5 parts by mass or more but less than 15 parts by mass, even more preferably 0.5 parts by mass or more but less than 10 parts by mass, and most preferably 1 part by mass or more but less than 7 parts by mass, relative to 100 parts by mass of all structural units in resin (A).

When resin (A) contains structural units derived from alkyl (meth)acrylates having a hydroxyl group, the content of this structural unit is preferably 20 parts by mass or less, more preferably 0.5 parts by mass or more but less than 15 parts by mass, even more preferably 0.5 parts by mass or more but less than 10 parts by mass, and most preferably 1 part by mass or more but less than 7 parts by mass, relative to 100 parts by mass of all structural units in resin (A).

From the viewpoint of preventing excessive peeling force of the separator membrane that can accumulate outside the adhesive layer, it is preferable that it substantially does not contain monomers with amine groups. Here, "substantially does not contain" means less than 0.1 parts by mass out of 100 parts by mass of all structural units constituting resin (A).

Regarding the reactivity of resin (A) with the crosslinking agent (B) described later, resin (A) preferably contains structural units derived from alkyl methacrylates with hydroxyl groups or structural units derived from carboxyl groups, more preferably both. The alkyl methacrylates with hydroxyl groups are 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. The carboxyl group-containing monomer is preferably acrylic acid.

The weight-average molecular weight (Mw) of resin (A) is preferably between 300,000 and 2,500,000, and more preferably between 500,000 and 2,500,000. If the weight-average molecular weight is above 300,000, the durability of the adhesive layer in high-temperature environments will be improved, and it will be easier to suppress defects such as buoyancy peeling between the adhesive and the light-selective absorbent adhesive layer, and aggregation and damage to the light-selective absorbent adhesive layer. If the weight-average molecular weight is below 2,500,000, it is advantageous, for example, from the viewpoint of coatability when the adhesive composition is processed into a sheet (applied to the substrate). From the perspective of balancing the durability of the light-selective absorbent adhesive layer and the coatability of the adhesive composition, a weight-average molecular weight (WM) is preferably 600,000 to 1,800,000, more preferably 700,000 to 1,700,000, and particularly preferably 1,000,000 to 1,600,000. Furthermore, the molecular weight distribution (Mw/Mn), expressed as the ratio of weight-average molecular weight (Mw) to number-average molecular weight (Mn), is typically 2 to 10, preferably 3 to 8. The weight-average molecular weight can be analyzed by gel dialysis and is a value converted from standard polystyrene.

When resin (A) is dissolved in ethyl acetate to prepare a 20% by mass solution, the viscosity at 25°C is preferably below 20 Pa·s, and more preferably between 0.1 and 15 Pa·s. Viscosities within this range are advantageous from the viewpoint of coatability when the adhesive composition is applied to a substrate. Furthermore, the viscosity can be measured using a Brookfield viscometer.

The resin (A) of this invention can be manufactured by known methods such as solution polymerization, bulk polymerization, suspension polymerization, and emulsion polymerization, with solution polymerization being particularly preferred. Solution polymerization can be exemplified by, for example, mixing monomers and an organic solvent, adding a thermal polymerization initiator under a nitrogen atmosphere, and stirring for approximately 3 to 15 hours at a temperature of 40 to 90°C, preferably 50 to 80°C. To control the reaction, the monomers or thermal polymerization initiator can be added continuously or intermittently during polymerization. The monomers or thermal initiator can be already added to the organic solvent.

Polymerization initiators can include thermal polymerization initiators and photopolymerization initiators. Examples of photopolymerization initiators include 4-(2-hydroxyethoxy)phenyl(2-hydroxy-2-propyl)one. Examples of thermal polymerization initiators include: 2,2’-azobisisobutyronitrile, 2,2’-azobis(2-methylbutyronitrile), 1,1’-azobis(cyclohexane-1-formonitrile), 2,2’-azobis(2,4-dimethylpentanonitrile), 2,2’-azobis(2,4-dimethyl-4-methoxypentanonitrile), dimethyl-2,2’-azobis(2-methylpropionate), 2,2’-azobis(2-hydroxymethylpropionitrile), and other azo compounds; lauryl peroxide, tert-butylhydrogen peroxide, benzoyl peroxide, tert-butylbenzoyl peroxide, and cumene hydroperoxide. Organic peroxides include hydroperoxide, diisopropyl peroxide, dipropyl peroxide, tributyl peroxyneodecanoate, tributyl permethylacetic acid, and (3,5,5-trimethylhexylidene peroxide); inorganic peroxides include potassium persulfate, ammonium persulfate, and hydrogen peroxide. Additionally, redox initiators that combine peroxides and reducing agents can also be used.

The proportion of polymerization initiator is approximately 0.001 to 5 parts by mass relative to 100 parts by mass of the total monomers constituting resin (A). The polymerization of resin (A) can be performed using a polymerization method utilizing active energy rays (such as ultraviolet rays).

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; and ketones such as acetone, methyl ethyl ketone, and methyl isobutyl ketone.

Resin (A) is preferably a resin that satisfies formula (1) below, and even more preferably a resin that satisfies formula (2) below.

ε(405)≧0.02 (1) [In equation (1), ε(405) represents the g/cm absorptivity of the resin at a wavelength of 405 nm. The unit of g/cm absorptivity is L/(g‧cm).]

ε(405)/ε(440)≧5 (2) [In equation (2), ε(405) represents the gamma-ray absorptivity of the resin at a wavelength of 405 nm, and ε(440) represents the gamma-ray absorptivity of the resin at a wavelength of 440 nm.]

Furthermore, the gamma absorbance coefficient of resin (A) can be determined by the method described in the embodiments.

The higher the ε(405) value of resin (A), the easier it is to absorb light with a wavelength of 405nm. A ε(405) value of 0.02L/(g‧cm) or higher is preferred, 0.1L/(g‧cm) or higher is even better, and 0.2L/(g‧cm) or higher is still even better. Typically, a value below 10L/(g‧cm) is acceptable.

When adhesive compositions containing resin (A) are applied to display devices such as organic electroluminescent displays (organic EL displays) or liquid crystal displays (FPDs: flat panel displays), if the ε (405) of resin (A) is 0.02 L/(g‧cm) or higher, the absorption performance of visible light near 400 nm is good. Therefore, the degradation of retardation films or organic EL emitting elements used in such displays due to visible light can be suppressed.

The higher the value of resin (A)'s ε(405)/ε(440), the more selectively it absorbs light with wavelengths around 400 nm. A value of ε(405)/ε(440) of 5 or higher is preferred, 50 or higher is even better, 75 or higher is still better, and 100 or higher is exceptionally good.

If the ε(405)/ε(440) of resin (A) is 5 or higher, then when an adhesive composition containing resin (A) is applied to display devices such as organic EL displays or liquid crystal displays (FPDs: flat panel displays), it will not hinder the color performance of the display device, and it can absorb light near 405nm and suppress light degradation of retardation films or organic EL elements.

(Other components contained in the adhesive composition)

The adhesive composition may further contain crosslinking agents (B), silicone compounds (D), antistatic agents, light-selective absorbers, and other resins besides resin (A).

Of the 100% by weight solids of the adhesive composition, the resin (A) content is typically 60% to 99.99% by weight, preferably 70% to 99.9% by weight, and even more preferably 80% to 99.7% by weight.

Adhesive compositions may contain crosslinking agents (B).

Crosslinking agents (B) can include: isocyanate-based crosslinking agents, epoxy-based crosslinking agents, aziridine-based crosslinking agents, metal chelate-based crosslinking agents, etc. In particular, from the perspectives of the adhesive composition's pot life, adhesive layer durability, and crosslinking speed, isocyanate-based crosslinking agents are preferred.

Isocyanate compounds are preferably compounds having at least two isocyanate groups (-NCO) in the molecule, such as aliphatic isocyanate compounds (e.g., hexamethylene diisocyanate), alicyclic isocyanate compounds (e.g., isoflavone diisocyanate, diphenylmethane diisocyanate, xylene diisocyanate), and aromatic isocyanate compounds (e.g., methylphenyl diisocyanate, xylene diisocyanate, diphenylmethane diisocyanate, naphthalene diisocyanate, triphenylmethane triisocyanate). Furthermore, crosslinking agent (B) can be an adduct of a polyol compound derived from the aforementioned isocyanate compound [e.g., an adduct from glycerol, trimethylolpropane, etc.]; or a derivative of an amine ester prepolymer type isocyanate compound that has undergone an addition reaction with a trimerocyanate, a burette-type compound, a polyether polyol, a polyester polyol, an acrylic polyol, a polybutadiene polyol, a polyisoprene polyol, etc. Crosslinking agent (B) can be used alone or in combination with two or more other types. Representative examples of these include adducts of aromatic isocyanate compounds (e.g., methylbenzyl diisocyanate, xylyl diisocyanate), aliphatic isocyanate compounds (e.g., hexamethylene diisocyanate), or polyol compounds of these compounds (e.g., glycerol, trimethylolpropane), or trimer isocyanates. If the crosslinker (B) is an aromatic isocyanate compound and/or a polyol compound of these compounds or an adduct of trimer isocyanates, it is advantageous to form the optimal crosslinking density (or crosslinking structure), thus improving the durability of the adhesive layer. In particular, if the adhesive layer is an adduct from methylbenzene diisocyanate compounds and/or such polyol compounds, durability can be improved, for example, even when the adhesive layer is applied to a polarizing plate.

The content of crosslinking agent (B) is typically 0.01 to 15 parts by weight, preferably 0.05 to 10 parts by weight, and even more preferably 0.1 to 5 parts by weight, relative to 100 parts by weight of resin (A).

Adhesive components may contain more silane compounds (D).

Examples of silane compounds (D) include: vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris(2-methoxyethoxy)silane, 3-glycidyloxypropyltrimethoxysilane, 3-glycidyloxypropyltriethoxysilane, 3-glycidyloxypropylmethyldimethoxysilane, 3-glycidyloxypropylethoxydimethylsilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-chloropropylmethyldimethoxysilane, 3-chloropropyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methylpropyltrimethoxysilane, etc.

The silane compound (D) can be a polysiloxane oligomer. Specific examples of polysiloxane oligomers, indicated by combinations of monomers, are as follows.

Oligopolymers containing 3-propyltrimethoxysilane-tetramethoxysilane, 3-propyltrimethoxysilane-tetraethoxysilane, 3-propyltriethoxysilane-tetramethoxysilane, and 3-propyltriethoxysilane-tetraethoxysilane oligopolymers; oligopolymers containing 3-propyl groups such as 3-propyltrimethoxysilane-tetramethoxysilane oligopolymers; and oligopolymers containing 3-propyltrimethoxysilane-tetramethoxysilane, 3-propyltrimethoxysilane-tetraethoxysilane oligopolymers. Oligopolymers containing methyl groups, such as methyltriethoxysilane-tetraethoxysilane oligomers; 3-glycidoxypropyltrimethoxysilane-tetramethoxysilane copolymers, 3-glycidoxypropyltrimethoxysilane-tetraethoxysilane copolymers, 3-glycidoxypropyltriethoxysilane-tetramethoxysilane copolymers, 3-glycidoxypropyltriethoxysilane-tetramethoxysilane copolymers, 3-glycidoxypropyltriethoxysilane-tetraethoxysilane copolymers, 3-glycidoxypropylmethyldimethoxysilane... 3-glycidyloxypropyl silane 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... Alkyl-tetraethoxysilane oligomers, 3-methacryloxypropyltriethoxysilane-tetramethoxysilane oligomers, 3-methacryloxypropyltriethoxysilane-tetraethoxysilane oligomers, 3-methacryloxypropylmethyldimethoxysilane-tetramethoxysilane oligomers, 3-methacryloxypropylmethyldimethoxysilane-tetraethoxysilane oligomers, 3-methacryloxypropylmethyldiethoxysilane-tetramethoxysilane oligomers, 3-methacryloxypropyltriethoxysilane-tetramethoxysilane oligomers, 3-methacryloxypropyltriethoxysilane-tetramethoxysilane oligomers Oligomers containing methacryloxypropyl groups, such as oxypropylmethyldiethoxysilane-tetraethoxysilane oligomers; 3-propenyloxypropyltrimethoxysilane-tetramethoxysilane oligomers, 3-propenyloxypropyltrimethoxysilane-tetraethoxysilane oligomers, 3-propenyloxypropyltriethoxysilane-tetraethoxysilane oligomers, 3-propenyloxypropyltriethoxysilane-tetraethoxysilane oligomers, 3-propenyloxypropylmethyldieth ... Oligomers containing acryloxypropyl groups, such as 3-propenylated propylmethyldimethoxysilane-tetraethoxysilane oligomers, 3-propenylated propylmethyldiethoxysilane-tetraethoxysilane oligomers, and 3-propenylated propylmethyldiethoxysilane-tetraethoxysilane oligomers; vinyltrimethoxysilane-tetramethoxysilane oligomers, vinyltrimethoxysilane-tetraethoxysilane oligomers, vinyltriethoxysilane- Tetramethoxysilane oligomers, vinyltriethoxysilane-tetraethoxysilane oligomers, vinylmethyldimethoxysilane-tetramethoxysilane oligomers, vinylmethyldimethoxysilane-tetraethoxysilane oligomers, vinylmethyldimethoxysilane-tetraethoxysilane oligomers, vinylmethyldiethoxysilane-tetraethoxysilane oligomers, vinylmethyldiethoxysilane-tetraethoxysilane oligomers, and other oligomers containing vinyl groups; 3-aminopropyltrimethoxysilane-tetramethoxysilane copolymers, 3-aminopropyltrimethoxysilane-tetraethoxysilane... Ethoxysilane copolymers, 3-aminopropyltriethoxysilane-tetramethoxysilane copolymers, 3-aminopropyltriethoxysilane-tetraethoxysilane copolymers, 3-aminopropylmethyldimethoxysilane-tetramethoxysilane copolymers, 3-aminopropylmethyldimethoxysilane-tetraethoxysilane copolymers, 3-aminopropylmethyldiethoxysilane-tetraethoxysilane copolymers, 3-aminopropylmethyldiethoxysilane-tetraethoxysilane copolymers, and other copolymers containing amino groups, etc.

The silane compound (D) can be a silane compound represented by the following formula (d1).

(In the formula, A represents an alkyldiyl group with 1 to 20 carbon atoms or a divalent alicyclic hydrocarbon group with 3 to 20 carbon atoms. The _-CH2- group constituting the alkyldiyl group and the alicyclic hydrocarbon group can be replaced by -O- or -CO-. ^R41 represents an alkyl group with 1 to 5 carbon atoms. ^R42 , ^R43 , ^R44 , ^R45 and ^R46 each independently represent an alkyl group with 1 to 5 carbon atoms or an alkoxy group with 1 to 5 carbon atoms.)

Alkadiyl groups with 1 to 20 carbon atoms represented by A include: methylene, 1,2-ethanediyl, 1,3-propanediyl, 1,4-butanediyl, 1,5-pentanediyl, 1,6-hexanediyl, 1,7-heptanediyl, 1,8-octanediyl, 1,9-nonanediyl, 1,10-decanediyl, 1,12-dodecanediyl, 1,14-tetradecanediyl, 1,16-hexadecanediyl, 1,18-octadecanediyl, and 1,20-eicosenediyl. Divalent alicyclic hydrocarbons with 3 to 20 carbon atoms include: 1,3-cyclopentanediyl and 1,4-cyclohexanediyl. The groups that constitute the alkyl diene and the alicyclic hydrocarbon by substitution of _-CH2 with _-O- or -CO- can be listed as follows: _{-CH2CH2 -O - CH2CH2- , -CH2CH2} - _O - _CH2CH2 -O- _CH2CH2- , _-CH2CH2 - _O - _CH2CH2 - _O - _CH2CH2- , _-CH2CH2 -CO _{- O - CH2CH2- , -CH2CH2 - O} - _CH2CH2 -CO _{- O - CH2CH2- , -CH2CH2CH2CH2 - O - CH2CH2- ,} and _{CH2CH2CH2CH2 - O - CH2CH2CH2- .}

Alkyl groups having 1 to 5 carbon atoms represented by R ⁴¹ to R ⁴⁵ include: methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tributyl, and pentyl; alkoxy groups having 1 to 5 carbon atoms represented by R ⁴² to R ⁴⁵ include: methoxy, ethoxy, propoxy, isopropoxy, butoxy, isobutoxy, tributoxy, and pentoxy.

Examples of silane compounds represented by 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, and 1,5-bis(trimethoxysilyl)propane. (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, etc. (triC1-5 alkoxy) (Dimethoxymethylsilyl)C1-10 alkyl groups; 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)hexane Alkanes, 1,8-bis(dimethoxymethylsilyl)octane, 1,8-bis(dimethoxyethylsilyl)octane, etc. (bis(diC1-5alkoxy-C1-5alkylsilyl)C1-10 alkanes); 1,6-bis(methoxydimethylsilyl)hexane, 1,8-bis(methoxydimethylsilyl)octane, etc. (bis(mono-C1-5alkoxy-diC1-5alkylsilyl)C1-10 alkanes, etc. Of these, 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, which are bis(triC1-3alkoxysilyl)C1-10 alkanes, are preferred, with 1,6-bis(trimethoxysilyl)hexane and 1,8-bis(trimethoxysilyl)octane being particularly preferred.

The content of silane compound (D) is typically 0.01 to 10 parts by weight relative to 100 parts by weight of resin (A), preferably 0.03 to 5 parts by weight, more preferably 0.05 to 2 parts by weight, and even more preferably 0.1 to 1 part by weight.

Adhesive components may contain more antistatic agents.

Antistatic agents include: surfactants, silicone compounds, conductive polymers, and ionic compounds, with ionic compounds being preferred. Examples of commonly used ionic compounds can be listed. The cations that make up ionic compounds include organic and inorganic cations. Examples of organic cations include: pyridinium cations, pyrrolidone cations, piperidinium cations, imidazodium cations, ammonium cations, strontium cations, and phosphonium cations. Inorganic cations include, for example, alkali metal cations such as lithium, potassium, sodium, and cesium; and alkaline earth metal cations such as magnesium and calcium. Particularly from the viewpoint of compatibility with (meth)acrylate resins, pyridinium cations, imidazoline cations, pyrrolidine cations, lithium cations, and potassium cations are preferred. The anionic components constituting ionic compounds can be either inorganic or organic anions, but for antistatic properties, anionic components containing fluorine atoms are preferred. Examples of anionic components containing fluorine atoms include: hexafluorosulfonate anion ( _PF6- ), bis(trifluoromethanesulfonyl)imidine anion [( _CF3SO2 ) _2N- ] _, bis(fluorosulfonyl)imidine anion _{[(FSO2)2N-], tetra(pentafluorophenyl)borate anion [(C6F5)4B- ] , etc. These} ionic compounds can be used alone or in combination of two or more. In _{particular, bis(trifluoromethanesulfonyl)imidin anions [(CF3SO2 ) 2N-} ], bis(fluorosulfonyl)imidin anions [( _FSO2 ) _2N- ], and tetra(pentafluorophenyl)borate anions _[ ( _C6F5 ) _4B- ] are preferred.

Regarding the long-term stability of the antistatic properties of the light-selectively absorbing adhesive layer formed by the adhesive composition, an ionic compound that is solid at room temperature is preferred.

The antistatic agent content is, for example, 0.01 to 20 parts by weight, preferably 0.1 to 10 parts by weight, and more preferably 1 to 7 parts by weight, relative to 100 parts by weight of resin (A).

The adhesive composition contains a resin (A) that is a light-selective absorbing polymer, and may or may not contain a light-selective absorber. Preferably, the adhesive composition does not contain a light-selective absorber. The light-selective absorber is one that selectively absorbs light of a specific wavelength, preferably containing a compound having at least one absorption maximum in the wavelength range of 360 nm to 420 nm, and more preferably containing a compound having an absorption maximum in the wavelength range of 380 nm to 410 nm. If a light-selective absorber is present, its content is preferably less than 0.1 parts by weight per 100 parts by weight of the total resin composition. The content of the light-selective absorber is related to the degree of decolorization at the tip of the polarizer under high temperature and humidity. Therefore, from the perspective of suppressing decolorization, the content of the light-selective absorber is preferably below 0.1 parts by weight.

There are no particular limitations on light-selective absorbers; examples include: benzophenone-based light-selective absorbers, benzotriazole-based light-selective absorbers, salicylate-based light-selective absorbers, benzophenone-based light-selective absorbers, cyanoacrylate-based light-selective absorbers, and trichlorobenzoyl peroxide-based light-selective absorbers. Organic light-selective absorbers, such as photoselective absorbers. More specifically, examples include: 5-chloro-2-(3,5-di-dibutyl-2-hydroxyphenyl)-2H-benzotriazole, (2-2H-benzotriazole-2-yl)-6-(straight-chain and side-chain dodecyl)-4-methylphenol, 2-hydroxy-4-benzylmethyloxybenzophenone, 2,4-benzylmethyloxybenzophenone, etc. These organic light-selective absorbers can be one type or two or more types combined.

Photoselective absorbers can be commercially available; examples include three. The photoselective absorbers include "Kemisorb 102" manufactured by CHEMIPBO KASEI Co., Ltd., "ADEKA stub LA46" and "ADEKA stub 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 light-selective absorbers include: ADEKA stub LA31 and ADEKA stub LA36 manufactured by ADEKA Corporation; Sumisorb 200, Sumisorb 250, Sumisorb 300, Sumisorb 340 and Sumisorb 350 manufactured by Sumitomo Chemical Chemtex Corporation; Kemisorb 74, Kemisorb 79 and Kemisorb 279 manufactured by CHEMIPRO KASEI Corporation; and TINUVIN 99-2, TINUVIN 900 and TINUVIN928 manufactured by BASF Corporation.

Light-selective absorbers can be inorganic. Examples of inorganic light-selective absorbers include: titanium oxide, zinc oxide, indium oxide, tin oxide, talc, kaolin, calcium carbonate, titanium oxide complex oxides, zinc oxide complex oxides, ITO (tin-doped indium oxide), and ATO (antimony-doped tin oxide). Examples of titanium oxide complex oxides include titanium oxide doped with silicon dioxide and alumina. One or more of these inorganic light-selective absorbers can be used. Organic and inorganic light-selective absorbers can also be used in combination.

The adhesive composition may contain one or more solvents, crosslinking catalysts, tackifiers, plasticizers, softeners, pigments, rust inhibitors, inorganic fillers, light-scattering microparticles, and other additives.

[Phase difference layer]

The optical laminate of this invention may contain a retardation layer laminated on the side of the light-selective absorbent adhesive layer opposite to the polarizer. The retardation layer may be one or two or more layers. The optical laminate 200 shown in Figure 2 contains a first retardation layer 30 and a second retardation layer 31.

The phase difference layer is an optical film that displays optical anisotropy. Examples of optical films that display optical anisotropy include stretched films obtained by stretching polymer films composed of polyvinyl alcohol, polycarbonate, polyester, polyarylate, polyimide, polyolefins, polycyclohexenes, polystyrene, polyurethane, polyether ether, polyvinyl difluoroethylene/polymethyl methacrylate, cellulose acetate, ethylene-vinyl acetate copolymer saponification, and polyvinyl chloride by approximately 1.01 to 6 times. Among stretched films, polymer films made by uniaxial or biaxial stretching of cellulose acetate, polyester, polycarbonate films, and cyclohexene resin films are preferred. Furthermore, the phase retardation layer can also be a phase retardation layer composed of a cured polymeric liquid crystal compound, formed by coating/orienting a polymeric liquid crystal compound onto a substrate to exhibit optical anisotropy.

Furthermore, in this specification, the term "phase retardation layer" also includes phase retardation layers containing zero retardation, such as uniaxial phase retardation films, low photoelasticity phase retardation films, and wide field-of-view phase retardation films.

A zero-delay phase difference layer refers to a film where the frontal delay Re and the thickness-direction delay Rth are both within the range of -15 to 15 nm, and it is optically isotropic.

Zero-delay films can be categorized as follows: resin films composed of cellulose-based resins, polyolefin-based resins (chain polyolefin resins, polycycloolefin resins, etc.), or polyethylene terephthalate-based resins. Cellulose-based or polyolefin-based resins are preferred due to their ease of control over delay values and readily available availability. Zero-delay films can also be used as protective films. Examples of zero-delay films include: "Z-TAC" (trade name) sold by Fuji Film Co., Ltd., "ZERO TAC" (registered trademark) sold by Konica Minolta Opto Co., Ltd., and "ZF-14" (trade name) sold by ZEON Co., Ltd. of Japan.

In the optical laminate of this invention, the retardation layer is preferably a hardened retardation layer of a polymeric liquid crystal compound.

The phase retardation layers of cured polymeric liquid crystal compounds can be categorized into five states.

First morphology: Rod-shaped liquid crystal compounds are phase retardation layers oriented horizontally relative to the supporting substrate.

Second morphology: Rod-shaped liquid crystal compounds are phase retardation layers oriented vertically relative to the supporting substrate.

Third state: Rod-shaped liquid crystal compounds are phase difference layers whose orientation is changed in an in-plane spiral manner.

Fourth form: a tilted phase retardation layer in a disk-shaped liquid crystal compound system

Fifth type: Disc-shaped liquid crystal compounds are biaxial phasor layers oriented vertically relative to the supporting substrate.

For example, optical films used in organic electroluminescent displays are suitable for use in their first, second, and fifth forms. Alternatively, phase retardation layers of these forms can be laminated.

The retardation layer is a layer composed of a polymer of a polymeric liquid crystal compound in an aligned state (hereinafter sometimes referred to as an "optical anisotropy layer"). Preferably, the retardation layer exhibits inverse wavelength dispersivity. Inverse wavelength dispersivity refers to the optical characteristic that the phase difference value within the alignment plane of the liquid crystal at shorter wavelengths is smaller than the phase difference value within the alignment plane at longer wavelengths. Preferably, the retardation film satisfies equations (7) and (8) below. Furthermore, Re(λ) represents the in-plane phase difference value for light with a wavelength of λ nm.

Re(450)/Re(550)≦1 (7)

1≦Re(630)/Re(550) (8)

In the optical laminate of this invention, when the phase difference layer is in the first form and has inverse wavelength dispersion, the color rendering in the black display of the display device is reduced, which is preferable. In the aforementioned equation (7), it is even better if it is 0.82≦Re(450)/Re(550)≦0.93. It is even better if it is 120≦Re(550)≦150.

The polymerizable liquid crystal compounds used in the formation of the phase détente layer can be listed as compounds containing polymerizable groups in "3.8.6 Network (Fully Crosslinked Type)" and "6.5.1 Liquid Crystal Materials b. Polymerizable Nematic Liquid Crystal Materials" of the Liquid Crystal Compendium (edited by the Liquid Crystal Compendium Editorial Committee, published by Maruzen (Co., Ltd.) on October 30, 2013), as well as those in Japanese Patent Application Publication No. 2010-31223. Polymerizable liquid crystal compounds as described in Japanese Publications, including Japanese Patent Application Publications No. 2010-270108, 2011-6360, 2011-207765, 2011-162678, 2016-81035, International Publication No. 2017/043438, and Japanese Patent Application Publications No. 2011-207765.

Methods for manufacturing a phase retardation layer from a layer composed of a polymer of a polymeric liquid crystal compound in an oriented state include, for example, the method described in Japanese Patent Application Publication No. 2010-31223.

The thickness of the phase retardation layer, which is a liquid crystal hardened layer formed by curing a polymeric 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.

As phase retardation layers that exhibit optical anisotropy through the coating/orientation of liquid crystal compounds, or through the coating of inorganic layered compounds, examples include: films known as temperature-compensated phase retardation films; the "NH film" (trade name: tilted rod-shaped liquid crystal film) sold by JX Energy (Co., Ltd.); the "WV film" (trade name: tilted disc-shaped liquid crystal film) sold by Fuji Film (Co., Ltd.); the "VAC film" (trade name: fully biaxially oriented film) sold by Sumitomo Chemical (Co., Ltd.); and the "new VAC film" (trade name: biaxially oriented film) sold by Sumitomo Chemical (Co., Ltd.), etc.

The phase difference layer can be a λ/4 phase difference layer that imparts a phase difference of 1/4 wavelength division to the transmitted light, a λ/2 phase difference layer that imparts a phase difference of 1/2 wavelength division to the transmitted light, a positive A-plate, and a positive C-plate. As shown in Figure 2, the optical laminate 200 typically contains a first phase difference layer 30 and a second phase difference layer 31. Combinations of the first phase difference layer 30 and the second phase difference layer 31 include combinations of a λ/2 phase difference layer and a λ/4 phase difference layer, and combinations of a λ/4 phase difference layer and a positive C-plate, etc.

The optical laminate of this invention can be configured as a circular polarizer with a λ/4 phasor layer. The circular polarizer can be used as an anti-reflective polarizer.

[Adhesive layer]

The optical laminate of this invention may include an adhesive layer for bonding two layers. The adhesive layer may include an adhesive layer, a bonding agent layer (hereinafter also referred to as the "second bonding agent layer"), etc. The optical laminate 200 shown in Figure 2 includes an adhesive layer 33 spaced between the first retardation layer 30 and the second retardation layer 31, bonding the layers, and a second bonding agent layer 32 laminated on the surface opposite to the adhesive layer 33 of the second retardation layer 31.

The adhesive layer can be made of water-based adhesives, reactive energy radioactive adhesives, or thermosetting adhesives. The thickness of the adhesive layer is, for example, 10 nm to 20 μm, preferably 100 nm to 10 μm, and even more preferably 500 nm to 5 μm.

The second adhesive layer may be composed of the same adhesive composition as that forming the light-selective absorbent adhesive layer described above, or it may be composed of an adhesive composition whose main component is a resin such as (meth)acrylic, rubber, amine, ester, polysiloxane, or polyvinyl ether resin (hereinafter also referred to as the "second adhesive composition"). The second adhesive composition is preferably an adhesive composition using (meth)acrylic resins with excellent transparency, weather resistance, and heat resistance as the base polymer. The second adhesive composition may be of the active energy radiation curing type or the thermosetting type. The thickness of the second adhesive layer is typically between 0.1 μm and 150 μm, for example, between 8 μm and 60 μm. From a thinner profile perspective, 30 μm or less is preferred, and 20 μm or less is even better.

<Manufacturing Method of Optical Laminates>

Optical laminates 100 and 200 can be manufactured by a method including a step of bonding the layers constituting the laminate 100 to each other with an adhesive layer in between. When bonding the layers with an adhesive layer in between, to improve adhesion, it is preferable to apply a surface-activating treatment, such as corona treatment, to one or both sides of the bonding surface.

<Optical Laminations>

The optical laminate of this invention is planar, with an area ranging from, for example, 30mm × 30mm to 180mm × 90mm.

The optical laminate of this invention can be rectangular, square, or other rectangular shapes, or it can be a shape with a notch cut into part of the side forming the rectangle, or a semi-circular shape, or a shape with a through hole in the surface, i.e., an irregular shape.

The absorption axis of the polarizer constituting the optical laminate, when the optical laminate has a straight edge, can be parallel to that edge, orthogonal to that edge, or inclined at an angle (e.g., 45°).

When an optical laminate has a retardation layer, and this retardation layer has a slow axis in-plane, this slow axis can intersect the absorption axis of the polarizer constituting the optical laminate at 45°, 15°, or 75°.

Image display device

Optical laminates of the 100 and 200 series can be configured in front of the image display panel (viewing side) and used as constituent elements of an image display device. Optical laminates belonging to the category of circular polarizers can also be used in image display devices as anti-reflective polarizers to impart anti-reflective properties. Image display devices are not particularly limited and examples include: organic electroluminescent (organic EL) display devices, inorganic electroluminescent (inorganic EL) display devices, liquid crystal display devices, and electric field luminescent (ESP) display devices.

[Implementation Example]

The following examples illustrate the invention in detail, but the invention is not limited to these examples. Unless otherwise specified, "%" and "parts" in the examples and comparative examples refer to "mass %" and "parts by mass".

[Fabrication of a Single-Sided Protective Polarizing Plate]

(Production of polarizing film)

A 20 μm thick polyvinyl alcohol film with a degree of polymerization of 2400 and a saponification degree of 99% or higher was uniaxially stretched on a hot roller to a stretch ratio of 4.1 times, kept in a taut state, and then immersed in a dyeing bath containing 0.05 parts by weight of iodine and 5 parts by weight of potassium iodide per 100 parts by weight of water at 28°C for 60 seconds.

Next, the sample 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. Afterward, it was washed with pure water at 10°C and dried to obtain the polarizer. The obtained polarizer had a thickness of 8 μm and a boron content of 4.3% by weight.

(Preparation of water-based adhesives)

Relative to 100 parts by weight of water, dissolve 3 parts by weight of carboxyl-modified polyvinyl alcohol (Kuraray Co., Ltd., trade name "KL-318"), and add 1.5 parts by weight of a water-soluble epoxy resin, a polyamide epoxy additive (Taoka Chemical Co., Ltd., trade name "Sumirez resin (registered trademark) 650(30), aqueous solution with a solids concentration of 30% by weight"), to prepare an aqueous adhesive.

(Protective film A and peeling film B)

A protective film A is a 3μm thick hard coating formed on a 25μm thick stretched film of nordrenene-based resin. This film (manufactured by Nippon Paper Co., Ltd., trade name "COP25ST-HC") is used.

A cellulose triacetate membrane (manufactured by Fuji Film 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/ ^m²‧24hr .

(Fabrication of a single-sided protective polarizing plate)

The polarizing film is continuously transported while the protective film A is continuously rolled out from the roll of the protective film A. Meanwhile, the release film B is continuously rolled up from the roll of the release film B. An aqueous adhesive is injected between the polarizing film and the corona-treated protective film A, while pure water is injected between the polarizing film and the release film B. Through a laminating roller, a laminated film consisting of protective film A, aqueous adhesive, polarizing film, pure water, and release film B is obtained. The laminated film is transported and heated in a drying oven at 80°C for 300 seconds to dry the aqueous adhesive and simultaneously evaporate and remove the pure water separating the polarizer and release film B, resulting in a single-sided protective polarizer with the release film attached. The release film B is then peeled off from the single-sided protective polarizer with the release film attached, yielding the single-sided protective polarizer.

[Fabrication of Phase Difference Layers]

(First liquid crystal curing layer)

The first liquid crystal curing layer (first phasing layer) is constructed from a nematic liquid crystal compound cured layer, an alignment film, and a transparent substrate, resulting in a phase difference of λ/4. Furthermore, the combined thickness of the nematic liquid crystal compound cured layer and the alignment layer is 2 μm.

(Fabrication of the second liquid crystal curing layer)

A coating solution for directional layer formation was prepared by dissolving 10.0 parts by weight of polyethylene glycol di(meth)acrylate (manufactured by Shin-Nakamura Chemical Industry Co., Ltd., A-600), 10.0 parts by weight of trimethylolpropane triacrylate (manufactured by Shin-Nakamura Chemical Industry Co., Ltd., A-TMPT), and 10.0 parts by weight of 1,6-hexanediol di(meth)acrylate (manufactured by Shin-Nakamura Chemical Industry Co., Ltd., A-HD-N), which are components used for directional layer formation; and 1.50 parts by weight of Irgacure 907 (manufactured by BASF, Irg-907), which is used as a photopolymerization initiator, in 70.0 parts by weight of methyl ethyl ketone solvent.

A 20 μm thick strip of cyclic olefinic resin (COP) film (manufactured by ZEON Corporation, Japan) was used as the substrate film. An orientation layer forming coating was applied to one side of the substrate film using a rod coater.

After applying a heat treatment of 80°C for 60 seconds, the coated layer is irradiated with 220 mJ/ ^cm² of ultraviolet (UVB) to polymerize and harden the composition for forming the orientation layer, thus forming an orientation layer with a thickness of 2.3 μm on the substrate film.

A coating solution for forming a phase retardation layer was prepared by dissolving 20.0 parts by weight of a photopolymerizable nematic liquid crystal compound (Merck, RMM28B) as a component for forming a phase retardation layer and 1.0 parts by weight of Irgacure 907 (BASF, Irg-907) as a photopolymerization initiator in 80.0 parts by weight of propylene glycol monomethyl ether acetate solvent.

A phase retardation layer forming liquid was applied to the previously obtained alignment layer, and the coating was heat-treated at 80°C for 60 seconds. Afterwards, the phase retardation layer forming composition was polymerized and hardened by irradiation with 220 mJ/ ^cm² of ultraviolet (UVB) light, forming a 0.7 μm thick phase retardation layer on the alignment layer. Thus, a second liquid crystal curing layer (second phase retardation layer) with a thickness of 3 μm, consisting of the alignment layer and the phase retardation layer, was obtained on the substrate film.

(Fabrication of phase difference integrators)

A first liquid crystal layer and a second liquid crystal layer are bonded together using a UV-curable adhesive (1 μm thick), with their respective liquid crystal layer surfaces (the sides opposite to the substrate film) as bonding surfaces. Next, UV light is irradiated to cure the UV-curable adhesive, creating a phase retardation laminate comprising the first and second liquid crystal curing layers. The thickness of the phase retardation laminate comprising the first liquid crystal curing layer, the UV-curable adhesive layer, and the second liquid crystal curing layer is 6 μm.

[Fabrication of a light-selective absorbent adhesive layer]

<Adhesive layer used in the optical laminate of Embodiment 1 (1)>

(Synthesis of photoselectively absorbing monomers)

A 300 mL four-necked flask equipped with a Dimroth condenser and a thermometer was placed in a nitrogen atmosphere. 10 parts of 2-hydroxyethyl acrylate, 8.1 parts of cyanoacetate, 1.1 parts of N,N-dimethyl-4-aminopyridine, 0.95 parts of dibutylhydroxytoluene, and 50 parts of toluene were added and stirred with a magnetic stirrer. After cooling in an ice bath and confirming the internal temperature reached 10°C, 12 parts of N,N-diisopropylcarbodiimide were added dropwise over 1 hour. After the addition was completed, the mixture was kept at an internal temperature of 0-10°C for another 2 hours. Subsequently, the mixture was filtered under reduced pressure to remove insoluble components, yielding 70 parts of a filtrate containing the compound represented by UVA-M-02.

A 300 mL four-necked flask equipped with a Deutsche cooling tube and a thermometer was placed in a nitrogen atmosphere. 20 parts of a compound (represented as UVA-M-01) synthesized according to Japanese Patent Application Publication No. 2014-194508, 7.1 parts of acetic anhydride, 70 parts of filtrate containing UVA-M-02, and 40 parts of acetonitrile were added and stirred with a magnetic stirrer. At an internal temperature of 25°C, 9 parts of N,N-diisopropylethylamine were added dropwise to the obtained mixture over 1 hour. The mixture was then kept at an internal temperature of 25°C for 2 hours. 200 g of ice water was added to the mixture and stirred. The precipitated crude biomass was then removed by reduced pressure filtration. The crude product was recrystallized in isopropanol to obtain 10 parts of the compound represented by UVA-01. The obtained compound represented by UVA-01 was identified by LC-MS and ^1H -NMR.

(Preparation of the light-selective absorber polymer (A-1))

In a reaction vessel equipped with a cooler, nitrogen inlet, thermometer, and stirrer, 96 parts by mass of butyl acrylate (referred to as "BA" in Table 1), 3 parts by mass of 2-hydroxyethyl acrylate (referred to as "HEA" in Table 1), and 1 part by mass of a light-selective absorbing monomer indicated as UVA-01 (total solids 100 parts by mass) are mixed with 135 parts by mass of ethyl acetate as a solvent. Nitrogen gas is used to replace the air in the apparatus to eliminate oxygen, and the internal temperature is simultaneously raised to 60°C.

To the obtained mixture, add the total amount of a solution containing 0.4 parts of azobisisobutyronitrile (polymerization initiator) dissolved in 10 parts of ethyl acetate. The obtained mixture was kept at 60°C for 1 hour, then the internal temperature was maintained at 50-70°C while ethyl acetate was continuously added to the reaction vessel at a rate of 17.3 parts/hr. Addition of ethyl acetate was stopped when the acrylic resin concentration reached 35%. The internal temperature was further maintained at 50-70°C for 12 hours after the addition of ethyl acetate. Ethyl acetate was then added to the obtained mixture of light-selective absorbing polymer (A-1) to adjust the resin concentration to 20%, thus preparing an ethyl acetate solution of the light-selective absorbing polymer (A-1). The light-selective absorbing polymer (A-1), converted from polystyrene by GPC, has a weight-average molecular weight (Mw) of 500,000 and an Mw/Mn ratio of 7.5. The glass transition temperature obtained by DSC is -48.4℃.

(Preparation of adhesive composition and adhesive layer)

(a) Preparation of adhesive components

In an ethyl acetate solution (resin concentration: 20%) of the light-selective absorbing polymer (A-1), 0.5 parts of a crosslinking agent (Coronate L, 75% solids: manufactured by Tosoh) and 0.5 parts of a silane compound (Shin-Etsu Chemical Industry Co., Ltd.: KBM-403) were added relative to 100 parts of the solids of the solution. 2-Butanone was then added to achieve a solids concentration of 14% to obtain the adhesive composition (1). Furthermore, the amount of the crosslinking agent (Coronate L) was calculated as the mass fraction of the active ingredient.

(b) Preparation of the adhesive layer

On the release-treated surface of a polyethylene terephthalate film (Lintec SP-PLR382050, hereinafter referred to as "septum") that has undergone release treatment, the adhesive composition prepared in (a) above was applied using an applicator to achieve a 5 μm thickness of adhesive layer after drying. The adhesive layer was then dried at 100°C for 1 minute to create an adhesive layer. This obtained adhesive layer is designated as adhesive layer (1).

<Adhesive layer used in the optical laminate of Embodiment 2 (2)>

An adhesive layer (2) was prepared using a light-selective absorbing polymer (A-2) in the same manner as the adhesive layer (1) of Example 1. The light-selective absorbing polymer (A-2) differs only in that the amount of BA in the formulation of the light-selective absorbing polymer (A-1) is set to 95 parts by mass, and the amount of the light-selective absorbing monomer indicated by UVA-01 is set to 2 parts by mass. The light-selective absorbing polymer (A-2) has a weight-average molecular weight (Mw) of 500,000 converted from polystyrene obtained by GPC, and an Mw/Mn ratio of 6.3.

<Adhesive layer (3) used in the optical laminate of Embodiment 3>

An adhesive layer (3) was prepared using a light-selective absorbing polymer (A-3) in the same manner as the adhesive layer (1) of Example 1. The light-selective absorbing polymer (A-3) differs only in that the BA in the formulation of the light-selective absorbing polymer (A-1) is set to 93 parts by mass, and the amount of the light-selective absorbing monomer represented by UVA-01 is set to 4 parts by mass. The light-selective absorbing polymer (A-3) has a weight-average molecular weight (Mw) of 600,000 converted from polystyrene obtained by GPC, and an Mw/Mn ratio of 7.0.

<Adhesive layer (4) used in the optical laminate of Comparative Example 1>

(Preparation of acrylic resin (A-4))

In a reaction vessel equipped with a coolant, nitrogen inlet pipe, thermometer, and stirrer, a mixed solution consisting of 61.9 parts butyl acrylate, 1.9 parts 2-hydroxyethyl acrylate, and 86.4 parts ethyl acetate as solvent is added. Nitrogen gas is used to replace the air in the apparatus to eliminate oxygen, and the internal temperature is raised to 60°C. Then, the entire amount of a solution consisting of 0.4 parts azobisisobutyronitrile (polymerization initiator) dissolved in 10 parts ethyl acetate is added. The obtained mixture was kept at 60°C for 1 hour, then the internal temperature was maintained between 50 and 70°C while ethyl acetate was continuously added to the reaction vessel at a rate of 17.3 parts/hr. The addition of ethyl acetate was stopped when the acrylic resin concentration reached 35%, and the temperature was maintained at this level for 12 hours after the start of ethyl acetate addition. Finally, ethyl acetate was added again to adjust the acrylic resin concentration to 20%, thus preparing an ethyl acetate solution of the acrylic resin. The obtained acrylic resin had a weight-average molecular weight (Mw) of 600,000 converted from polystyrene obtained by GPC, and an Mw/Mn ratio of 7.0. The obtained acrylic resin was designated as acrylic resin (A-4). The glass transition temperature obtained by DSC was -52.9°C.

(Preparation of adhesive composition and adhesive layer)

(a) Preparation of adhesive components

In an ethyl acetate solution of acrylic resin (A-4) (resin concentration: 20%), relative to 100 parts of the solids of the solution, 0.5 parts of a crosslinking agent (Coronate L, 75% solids: manufactured by Tosoh), 0.5 parts of a silane compound (Shin-Etsu Chemical Industry Co., Ltd.: KBM-403), and 2.5 parts of the compound represented by the following formula (aa2) as the light-selective absorbing compound (2) as described in paragraph [0142] of Japanese Patent Application Publication No. 2019-007001 (light-selective absorber), were added further to achieve a solids concentration of 14% to obtain an adhesive composition (4). Furthermore, the amount of the crosslinking agent (Coronate L) was the mass fraction of the active ingredient.

(b) Preparation of the adhesive layer

An adhesive layer (4) is made from the adhesive composition using the same method as in Embodiment 1.

<Adhesive layer (5) used in the optical laminate of Comparative Example 2>

Except for setting the amount of light-selective absorber to 3.7 parts in the preparation of the adhesive composition, the adhesive layer (5) is prepared using the same method as in the preparation of the adhesive layer (4).

<Adhesive layer (6) used in the optical laminate of Comparative Example 3>

Except for setting the amount of light-selective absorber to 2.5 parts and the thickness of the adhesive layer to 17 μm in the preparation of the adhesive composition, the adhesive layer (6) is prepared using the same method as in the preparation of adhesive layer (4).

[Creation of the Second Adhesive Layer]

In an ethyl acetate solution of the aforementioned acrylic resin (A-4) (resin concentration: 20%), 0.5 parts of a crosslinking agent (Coronate L, 75% solids: manufactured by Tosoh) and 0.5 parts of a silane compound (Shin-Etsu Chemical Industry Co., Ltd.: KBM-403) were mixed, and 2-butanone was further added to achieve a solids concentration of 14% to obtain the adhesive composition (7). Furthermore, the amount of the crosslinking agent (Coronate L) was calculated as the mass fraction of the active ingredient.

On the release treatment surface of the septum used in the fabrication of the photoselective absorbent adhesive layer, the adhesive composition (7) is applied using a coating applicator to achieve a dried adhesive layer thickness of 15 μm or 25 μm. The layer is then dried at 100°C for 1 minute to create a second adhesive layer.

[Fabrication of Optical Laminates]

(Implementation Example 1)

An adhesive layer (1) is attached to the polarizer side of the fabricated single-sided protective polarizer, and the spacer film is peeled off. The side of the adhesive layer (1) with the spacer film removed is attached to the side of the first liquid crystal curing layer of the fabricated phase difference laminate, and the substrate film of the second liquid crystal curing layer is peeled off. A second adhesive layer with a spacer film and the thickness described in Table 1 is attached to the side with the substrate film removed. The optical laminate system of Embodiment 1 has the configuration shown in FIG. 2.

(Examples 2 and 3, and Comparative Examples 1 to 3)

Using the same method as in the optical laminate of Example 1, the optical laminate of Example 2 is manufactured by replacing the adhesive layer (1) of Example 1 with an adhesive layer (2), and the optical laminate of Example 3 is manufactured by replacing the adhesive layer (1) of Example 1 with an adhesive layer (3). The optical laminate of Comparative Example 1 was fabricated using an adhesive layer (4); the optical laminate of Comparative Example 2 was fabricated using an adhesive layer (5) instead of the adhesive layer (1) of Example 1; and the optical laminate of Comparative Example 3 was fabricated using an adhesive layer (6) instead of the adhesive layer (1) of Example 1.

[Absorbance Measurement of Adhesive Layer]

Adhesive layers (1) to (6) were respectively bonded to glass. After peeling off the spacer, a cycloolefin polymer (COP) film (ZF-14 manufactured by ZEON Corporation, Japan) was bonded to the adhesive layers to create an adhesive layer evaluation laminate. The adhesive layer evaluation laminate was mounted on a UV-2450 spectrophotometer (Shimadzu Corporation), and absorbance was measured in 1 nm increments within the wavelength range of 300 to 800 nm using the double-beam method. The absorbance of the fabricated adhesive layer at 410 nm is shown in Table 1. Furthermore, the absorbance of both the glass and the COP film at 410 nm was 0.

[Determination of weight-average molecular weight (Mw)]

The weight-average molecular weight (Mw) of the light-selective absorption polymers (A-1), (A-2), (A-3), and acrylic resin (A-4) was determined by particle size chromatography (SEC) using tetrahydrofuran as the mobile phase, yielding the polystyrene-converted number-average molecular weight (Mn). The determined (meth)acrylic polymers were dissolved in tetrahydrofuran at a concentration of approximately 0.05% by mass, and 10 μL of the solution was injected into the SEC. The mobile phase was flowed at a flow rate of 1.0 mL/min. The column used was a PLgel MIXED-B (manufactured by Polymer Laboratories). A UV-VIS detector (trade name: Agilent GPC) was used.

[Determination of Boron Content]

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

[Damp heat resistance test and observation of discoloration]

The interlayer membranes of the optical laminates obtained in Examples 1 to 3 and Comparative Examples 1 to 3 were peeled off and bonded to an alkaline glass plate, then placed in an environment of 65°C and 90%RH for 500 hours. Afterwards, a polarizing plate with crossed nicols was bonded to an alkaline glass surface opposite to the experimental optical laminate, and observed using an optical microscope. The observed images were saved. The optical microscope used was a "VHX-500" manufactured by KEYENCE Corporation. Figure 3 shows an example of an image observed using an optical microscope. In Figure 3, if one observes along the straight line indicated by the arrow pointing inward from the end 50 of the optical laminate (a straight line extending vertically from the end 50), it can be seen that there is a decolorized area 51 and an area that does not decolorize (non-decolorized area) 52.

[Determination of desaturation amount using image processing]

The image observed under a microscope was converted to 256 gray levels (0 to 255) using the image analysis software "ImageJ (free software)". The conversion to 256 gray levels (0 to 255) was performed by averaging the RGB values. Figure 4 shows an example of the converted data. The midpoint (the middle of the desaturated color gradient) of the desaturated region 51 and the non-desaturated region 52 in the tonal distribution in the vertical direction (arrow in Figure 3) relative to the end 50 of the optical laminate was taken as the desaturated end of the optical laminate (Figure 4), and the distance (μm) between the desaturated end and the end 50 of the optical laminate was measured as the desaturation distance. The decolorization distance coefficients of the optical laminates are shown in Table 1. A smaller decolorization distance indicates a narrower decolorization range and superior resistance to humidity and heat.

The decolorization distances of optical laminates using adhesive layers exhibiting the same absorbance were compared to each other (Example 1 and Comparative Example 1, Example 2 and Comparative Example 2, Example 3 and Comparative Example 3). The differences and the improvement rate of decolorization distance [(absolute value of difference / decolorization distance of Comparative Examples 1 to 3) × 100] are shown in Table 1.

[Table 1]

10: Polarizing film

11: Protective Film

20: Light-selective absorbent adhesive layer

100: Optical Layers

Claims (9)

An optical laminate comprises a polarizer and a light-selective absorbing adhesive layer laminated in contact with the polarizer; wherein the polarizer adsorbs oriented iodine and has a boron content of 5.0% by mass or less; the adhesive composition forming the light-selective absorbing adhesive layer includes a light-selective absorbing polymer; the adhesive composition does not contain a light-selective absorber, but excludes the light-selective absorbing polymer. The optical laminate as described in claim 1 further includes a protective film deposited on the side of the aforementioned polarizer opposite to the aforementioned light-selective absorbent adhesive layer. The optical laminate as described in claim 1 or 2, wherein the aforementioned light-selective absorbing polymer is a resin containing structural units having the structure shown in the following chemical formula (1) and having a glass transition temperature of 40°C or less, ＞N-C＝C-C＝C＜ (1) However, not all of the 1 N atom and 4 C atoms constituting chemical formula (1) are part or all of an aromatic heterocycle. The optical laminate as described in claim 3, wherein, in the aforementioned light-selective absorbing polymer, the content of the structural unit having the structure shown by the aforementioned chemical formula (1) is 0.01 parts by mass or more and 50 parts by mass or less, relative to 100 parts by mass of all structural units. The optical laminate as described in claim 1 or 2, wherein the weight-average molecular weight of the aforementioned light-selective absorbing polymer is 300,000 or more. The optical laminate as described in claim 1 or 2 further comprises a λ/4 phase difference layer, which is laminated on the side opposite to the aforementioned light-selective absorbent adhesive layer to the aforementioned polarizer. The optical laminate as described in claim 1 or 2 is an anti-reflective polarizing plate. An image display device includes an image display panel and an optical laminate as described in claim 7 disposed in front of the aforementioned image display panel. The image display device described in claim 8 is an organic EL display device.