CN116547144A - Adhesive composition for coated polarizing element, adhesive sheet for image display device constituent member, adhesive sheet with release film, adhesive sheet with image display device constituent member, laminate, coated polarizing element with adhesive layer, adhesive sheet with polarizing element, and image display device - Google Patents

Abstract

The adhesive composition for a coated polarizing element, which comprises the (meth) acrylic polymer (A), the ultraviolet absorber (B) and the radical polymerization initiator (C), has a transmittance of 50% or less at a wavelength of 400nm of an adhesive layer formed from the adhesive composition, and can be used in combination with the coated polarizing element, whereby the deterioration of the polarizing performance of the coated polarizing element with time due to exposure can be prevented.

Description

Adhesive composition for coated polarizing element, adhesive sheet for image display device constituent member, adhesive sheet with release film, adhesive sheet with image display device constituent member, laminate, coated polarizing element with adhesive layer, adhesive sheet with polarizing element, and image display device

Technical Field

The present invention relates to an adhesive composition which can be suitably used for organic electroluminescence (hereinafter, also referred to as "organic EL"). In particular, it relates to: the adhesive composition can be suitably used for a coated polarizing element, an adhesive sheet for a coated polarizing element formed from the adhesive composition, an adhesive sheet with a polarizing element comprising a coated polarizing element, an image display device using the adhesive sheet, a coated polarizing element with an adhesive layer comprising an adhesive layer formed from the adhesive composition, and an image display device using the coated polarizing element with an adhesive layer. In addition, it relates to: the adhesive sheet for image display device constituent members, the release film-equipped adhesive sheet using the adhesive sheet for image display device constituent members, the laminate sheet, and the image display device can be suitably used for bonding image display device constituent members.

Background

In recent years, with the trend of thinning and weight reduction of image display devices such as liquid crystal display devices and organic EL display devices, thinning of optically anisotropic members such as polarizing plates and retardation plates constituting the image display devices has been demanded.

The existing polarizing plate is generally: an adhesive is applied to a protective film such as a TAC (cellulose triacetate) film or a polyvinyl alcohol (PVA) film, or an adhesive sheet is laminated. For example, there are known: the polarizing plate is formed by laminating an adhesive layer/protective film/polarizing film (polarizing plate)/protective film/adhesive layer, or an adhesive layer/protective film/polarizing film (polarizing plate)/retardation plate/adhesive layer.

However, since such a conventional polarizing plate uses a polarizing plate in which a polyvinyl alcohol (PVA) film is stretched, it is very brittle and needs to be sandwiched between 2 protective films, and there is a limit in film formation.

Therefore, as means for thinning a polarizing element such as a polarizing plate, the following coated polarizing element has been attracting attention.

Since a liquid crystal compound having a polymerizable functional group (also referred to as a "polymerizable liquid crystal compound") has both the property as a polymerizable monomer and the property as a liquid crystal, when the liquid crystal compound is polymerized and cured in an aligned state, a cured product of a polymer having a fixed alignment, that is, an optically anisotropic material can be obtained.

Thus, by applying an optically anisotropic composition containing a polymerizable liquid crystal compound to a substrate and curing the composition in an aligned state, a polarizing film having optical anisotropy can be formed. The polarizing element thus obtained is generally called a coated polarizing element in many cases.

On the other hand, in order to suppress photodegradation of the image display device constituent members, an adhesive sheet containing an ultraviolet absorber is known which is disposed between the surface protection panel and the image display module.

For example, patent document 1 discloses an adhesive sheet having an acrylic adhesive layer, b is 0.42 or less, and the transmittance of light having a wavelength of 350nm is 5% or less.

Patent document 2 discloses an ultraviolet curable acrylic pressure-sensitive adhesive layer which is disposed between a polarizing film and a glass cover sheet or a plastic cover sheet in an image display device, and has a transmittance at a wavelength of 380nm of 40% or less and a transmittance at a wavelength of 400nm of 30% or more.

Prior art literature

Patent literature

Patent document 1: japanese patent application laid-open No. 2019-214722

Patent document 2: japanese patent laid-open publication 2016-155981

Disclosure of Invention

Problems to be solved by the invention

The coated polarizing element can be formed into a film by coating, and thus can be reduced in thickness, compared with conventional polarizing elements.

However, such a coated polarizing element is susceptible to degradation by light, and therefore, there is a problem in that the polarization performance is degraded with time due to light such as external light.

In addition, various optical members such as iodine used for a polarizing plate, an organic dye having dichroism, a liquid crystal panel further used for an image display device, an organic EL element, and the like have a problem of insufficient light resistance.

Therefore, the aforementioned adhesive sheet containing an ultraviolet absorber is considered to be used for a coated polarizing element.

However, the transparent adhesives for image display devices having a light absorbing function of patent documents 1 and 2 are not considered to be used in combination with a coating type polarizing element, and therefore, in the case of being used in a coating type polarizing element, it is difficult to prevent the deterioration of the polarizing performance of the coating type polarizing element with time due to light such as external light.

Accordingly, an object of the present invention is to provide: the adhesive composition or adhesive sheet for a coated polarizing element can prevent the deterioration of the polarizing performance of the coated polarizing element with time due to exposure by using the adhesive composition or adhesive sheet in combination with the coated polarizing element.

The transparent adhesives for image display devices having light absorption function of patent documents 1 and 2 supplement the function of a protective film layer for protecting a polarizing plate from ultraviolet rays, that is, a protective film layer containing an ultraviolet absorber. Accordingly, in order to cope with further reduction in film thickness and weight of the image display device, it is required to suppress photodegradation of the optical member without providing a protective film layer, and for this reason, the adhesive itself is required to have light resistance reliability.

Accordingly, another object of the present invention is to provide: the excellent light-resistant reliability enables to cope with the thinning and weight reduction of the image display device.

Solution for solving the problem

In order to solve the above problems, the present invention provides an adhesive composition for a coated polarizing element comprising a (meth) acrylic polymer (a), an ultraviolet absorber (B) and a radical polymerization initiator (C), wherein the adhesive composition has a transmittance at a wavelength of 400nm of 50% or less, and an adhesive sheet for a coated polarizing element comprising an adhesive material layer formed using the adhesive composition.

The present invention also provides an adhesive sheet for image display device constituent members, which is formed from an adhesive composition comprising a (meth) acrylic copolymer (A), a hydroxyl group-containing benzophenone compound (B1) and a radical polymerization initiator (C), and has a light transmittance at a wavelength of 400nm of less than 30%.

ADVANTAGEOUS EFFECTS OF INVENTION

The adhesive composition for a coated polarizing element or the adhesive sheet for a coated polarizing element of the present invention can prevent the deterioration of the polarizing performance of the coated polarizing element with time due to light such as external light by using the adhesive composition in combination with the coated polarizing element. Thus, the coated polarizing element can be bonded to and integrated with other image display device constituent members without using a protective film as in the prior art, and photodegradation can be prevented, so that the image display device can be advantageously reduced in film thickness, reduced in weight, and improved in photodegradation resistance.

The adhesive sheet for image display device constituent members according to the present invention is excellent in light-resistant reliability, and therefore, can bond and integrate the image display device constituent members without providing a protective film layer for protecting a polarizing plate from ultraviolet rays, that is, a protective film layer containing an ultraviolet absorber, as in the conventional art, and can prevent photodegradation of the image display device constituent members, and therefore, can contribute to thinning, weight saving, and improvement in photodegradation resistance of the image display device.

Drawings

Fig. 1 is a cross-sectional view showing an example of the adhesive sheet with a polarizing element or the adhesive sheet with a constituent member of an image display device of the present invention.

Fig. 2 is a cross-sectional view showing an example of the image display device of the present invention.

Fig. 3 is a cross-sectional view showing an example of the image display device of the present invention.

Fig. 4 is a cross-sectional view showing an example of the image display device of the present invention.

Fig. 5 is a cross-sectional view showing an example of the image display device of the present invention.

Fig. 6 is a cross-sectional view showing an example of the release film-carrying pressure-sensitive adhesive sheet of the present invention.

Fig. 7 is a cross-sectional view showing an example of the laminate sheet of the present invention.

Detailed Description

Next, the present invention will be described based on examples of embodiments. However, the present invention is not limited to the embodiments described below.

Adhesive composition I

The adhesive composition I for a coated polarizing element according to an example of the embodiment of the present invention (referred to as "the present adhesive composition I") contains a (meth) acrylic polymer (a), an ultraviolet absorber (B), and a radical polymerization initiator (C), and if necessary, contains a polyfunctional (meth) acrylate (D) and other components.

In the present invention, "(meth) acrylic polymer" means including acrylic copolymer and methacrylic copolymer, "(meth) acrylic ester" means including acrylic ester and methacrylic ester, and "(meth) acryl" means including acryl and methacryl.

In the present invention, the term "polarizing element" means an optical member having optical anisotropy, and the term "coated polarizing element" means a laminate including a film formed by coating an optically anisotropic composition containing a liquid crystal compound. Examples of the liquid crystal compound include polymerizable liquid crystal compounds, polymer liquid crystal compounds, and lyotropic liquid crystal compounds. For example, a cured product obtained by applying an optically anisotropic composition containing a polymerizable liquid crystal compound to a substrate and curing the composition in an aligned state can be used as a polarizing element. In this case, the substrate may be contained or not.

The adhesive composition I can be cured by heat as described later, or can be cured by active energy rays. In particular, curing by active energy rays is preferable because curing is not required and productivity is excellent.

The adhesive composition I can be cured in multiple stages as described later.

In addition, in the case of an adhesive sheet containing an ultraviolet absorber when curing by an active energy ray, the ultraviolet absorber prevents curing by an active energy ray, and therefore, it is generally difficult to use an active energy ray curing system, but in the present invention, it is dared to apply, and as a result, a good adhesive sheet can be obtained.

(meth) acrylic Polymer (A) >, and a process for producing the same

The (meth) acrylic polymer (a) may be a copolymer obtained by polymerizing a monomer component copolymerizable with the (meth) acrylic polymer (a) and a homopolymer of an alkyl (meth) acrylate.

Examples of the copolymer include a copolymer of an alkyl (meth) acrylate (a 1) having an alkyl group having 4 to 18 carbon atoms as a main component and a monomer component copolymerizable therewith.

The main component is a component that exerts a large influence on the properties of the (meth) acrylic polymer (a), and the content of the component is usually 30% by mass or more, preferably 35% by mass or more, more preferably 50% by mass or more, and particularly preferably 60% by mass or more of the entire (meth) acrylic polymer (a).

The (meth) acrylic polymer (a) may contain 2 or more different (meth) acrylic polymers.

Examples of the "alkyl (meth) acrylate having 4 to 18 carbon atoms (a 1)" include (meth) acrylic acid branched alkyl esters such as (meth) acrylic acid straight chain alkyl esters such as (meth) acrylic acid cetyl esters, (meth) acrylic acid isobutyl esters, (meth) acrylic acid sec-butyl esters, (meth) acrylic acid tert-butyl esters, (meth) acrylic acid isopentyl esters, (meth) acrylic acid neopentyl esters, (meth) acrylic acid 2-ethylhexyl esters, (meth) acrylic acid isooctyl esters, (meth) acrylic acid isononyl esters, (meth) acrylic acid isodecyl esters, (meth) acrylic acid isostearyl esters, (meth) acrylic acid branched alkyl esters such as (meth) lauryl esters, (meth) acrylic acid tridecyl esters, (meth) acrylic acid tetradecyl esters, (meth) acrylic acid cetyl esters, (meth) acrylic acid stearyl esters, (meth) acrylic acid linear alkyl esters such as (meth) acrylic acid stearyl esters, (meth) acrylic acid, isobutyl esters, (meth) acrylic acid tert-butyl esters, (meth) acrylic acid tert-amyl esters, (meth) acrylic acid neopentyl esters, (meth) acrylic acid 2-ethylhexyl esters, (meth) acrylic acid isooctyl esters, (meth) acrylic acid isononyl esters, (meth) acrylic acid isodecyl esters, (meth) acrylic acid isostearyl esters, (meth) acrylic acid, and (meth) acrylic acid cyclopentene esters, (5, and (meth) acrylic acid) t-butyl esters Alicyclic (meth) acrylates such as dicyclopentenyloxyethyl (meth) acrylate and isobornyl (meth) acrylate. They may be used in combination of 1 or 2 or more.

The content of the alkyl (meth) acrylate (a 1) is preferably 30 mass% or more, more preferably 40 mass% or more, still more preferably 50 mass% or more, particularly preferably 60 mass% or more, and most preferably 65 mass% or more, based on the entire component of the (meth) acrylic polymer (a), from the viewpoint of improving stress relaxation property and heat resistance reliability in forming the adhesive sheet or the adhesive layer.

In addition, the content of the alkyl (meth) acrylate (a 1) is preferably 90 mass% or less, more preferably 85 mass% or less, further preferably 80 mass% or less, particularly preferably 75 mass% or less, and most preferably 70 mass% or less, with respect to the entire component of the (meth) acrylic polymer (a), from the viewpoint of suppressing the decrease in the adhesive force.

Examples of the monomer component copolymerizable with the alkyl (meth) acrylate (a 1) having 4 to 18 carbon atoms in the alkyl group include a hydroxyl group-containing monomer (a 2), a (meth) acrylate monomer or vinyl ester-based monomer (a 3) having 1 to 3 carbon atoms in the alkyl group, a functional group-containing ethylenically unsaturated monomer (a 4) (excluding the hydroxyl group-containing monomer (a 2)), and other copolymerizable monomers (a 5).

Examples of the "hydroxyl group-containing monomer (a 2)", include 2-hydroxyethyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 5-hydroxypentyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, 8-hydroxyoctyl (meth) acrylate and other (meth) acrylate hydroxyl esters, caprolactone-modified 2-hydroxyethyl (meth) acrylate and other caprolactone-modified monomers, diethylene glycol (meth) acrylate, polyethylene glycol (meth) acrylate and other oxyalkylene-modified monomers, phthalic acid 2-acryloyloxyethyl-2-hydroxyethyl and other primary hydroxyl group-containing monomers; secondary hydroxyl group-containing monomers such as 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, and 3-chloro-2-hydroxypropyl (meth) acrylate; and tertiary hydroxyl group-containing monomers such as 2, 2-dimethyl-2-hydroxyethyl (meth) acrylate. They may be used alone or in combination of 2 or more.

Among the hydroxyl group-containing monomers (a 2), a primary hydroxyl group-containing monomer is preferable, 2-hydroxyethyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate are particularly preferable, and 2-hydroxyethyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate are particularly preferable, in view of excellent balance between moist heat resistance and heat resistance.

The lower limit of the content of the hydroxyl group-containing monomer (a 2) is usually 3 parts by mass or more, preferably 5 parts by mass or more, more preferably 8% by mass or more, still more preferably 10% by mass or more, and particularly preferably 12% by mass or more, based on the entire component of the (meth) acrylic polymer (a), from the viewpoint of improving moist heat resistance.

On the other hand, the upper limit of the content of the hydroxyl group-containing monomer (a 2) is usually 60 mass% or less, preferably 45 mass% or less, more preferably 35 mass% or less, still more preferably 30 mass% or less, and particularly preferably 25 mass% or less, from the viewpoint of suppressing self-crosslinking reaction of the adhesive composition and improving processability and heat resistance reliability.

Examples of the "alkyl group-containing (meth) acrylate monomer having 1 to 3 carbon atoms or vinyl ester-based monomer (a 3)" include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, vinyl propionate, and vinyl acetate. These monomers (a 3) may be used alone or in combination of 2 or more.

Among the above components (a 3), methyl (meth) acrylate and ethyl (meth) acrylate are preferably used from the viewpoint of improving the aggregation force when used as a binder.

In addition, the lower limit value of the content of the component (a 3) is preferably 5% by mass or more, more preferably 7% by mass or more, and still more preferably 10% by mass or more, based on the entire component of the (meth) acrylic polymer (a), from the viewpoint of improving the aggregation force when used as a binder. In addition, the upper limit value of the content of the component (a 3) is preferably 40 mass% or less, more preferably 30 mass% or less, and further preferably 20 mass% or less, relative to the entire component of the (meth) acrylic polymer (a), from the viewpoint of improving processability.

Examples of the "functional group-containing ethylenically unsaturated monomer (a 4)" include monomers having a functional group having a nitrogen atom, carboxyl group-containing monomers, acetoacetyl group-containing monomers, isocyanate group-containing monomers, and glycidyl group-containing monomers.

Among them, in terms of imparting aggregation force and crosslinking acceleration, a monomer containing a functional group having a nitrogen atom is preferable, an amino group-containing monomer and an amide group-containing monomer are more preferable, and an amino group-containing monomer is further preferable.

Examples of the "amino group-containing monomer" as the "functional group-containing monomer having a nitrogen atom" include (meth) acrylic acid esters containing a primary amino group such as aminomethyl (meth) acrylate and aminoethyl (meth) acrylate; secondary amino group-containing (meth) acrylates such as t-butylaminoethyl (meth) acrylate and t-butylaminopropyl (meth) acrylate; tertiary amino group-containing (meth) acrylates such as ethylaminoethyl (meth) acrylate, dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, dimethylaminopropyl (meth) acrylate, diethylaminopropyl (meth) acrylate, dimethylaminopropyl acrylamide, and the like; etc.

Examples of the "amide group-containing monomer" include (meth) acrylamide; n-alkyl (meth) acrylamides such as N-methyl (meth) acrylamide, N-ethyl (meth) acrylamide, N-propyl (meth) acrylamide, N-butyl (meth) acrylamide, diacetone (meth) acrylamide, N' -methylenebis (meth) acrylamide, and the like; n, N-dialkyl (meth) acrylamides such as N, N-dimethyl (meth) acrylamide, N-diethyl (meth) acrylamide, N-dipropyl (meth) acrylamide, N-ethyl methacrylamide, N-diallyl (meth) acrylamide, and the like; hydroxyalkyl (meth) acrylamides such as N-hydroxymethyl (meth) acrylamide and N-hydroxyethyl (meth) acrylamide; alkoxyalkyl (meth) acrylamides such as N-methoxymethyl (meth) acrylamide and N- (N-butoxymethyl) (meth) acrylamide; etc.

Examples of the "carboxyl group-containing monomer" include (meth) acrylic acid, carboxyethyl (meth) acrylate, 2- (meth) acryloyloxyethyl hexahydrophthalate, 2- (meth) acryloyloxypropyl hexahydrophthalate, 2- (meth) acryloyloxyethyl phthalate, 2- (meth) acryloyloxypropyl phthalate, 2- (meth) acryloyloxyethyl maleate, 2- (meth) acryloyloxypropyl maleate, 2- (meth) acryloyloxyethyl succinate, 2- (meth) acryloyloxypropyl succinate, crotonic acid, fumaric acid, maleic acid, itaconic acid, monomethyl maleate, and monomethyl itaconate.

Examples of the "acetoacetyl-containing monomer" include 2- (acetoacetoxy) ethyl (meth) acrylate and allyl acetoacetate.

Examples of the "isocyanate group-containing monomer" include 2-acryloyloxyethyl isocyanate, 2-methacryloyloxyethyl isocyanate, and alkylene oxide adducts thereof. The isocyanate group may be protected with a blocking agent such as methyl ethyl ketoxime, 3, 5-dimethylpyrazole, 1,2, 4-triazole, diethyl malonate, etc.

Examples of the "glycidyl group-containing monomer" include glycidyl (meth) acrylate, allyl glycidyl (meth) acrylate, and the like.

These functional group-containing ethylenically unsaturated monomers (a 4) may be used alone or in combination of 2 or more.

The upper limit of the content of the functional group-containing ethylenically unsaturated monomer (a 4) is preferably 30 mass% or less, more preferably 20 mass% or less, still more preferably 10 mass% or less, and particularly preferably 5 mass% or less, based on the entire component of the (meth) acrylic polymer (a), from the viewpoint of improving the heat resistance and light resistance of the adhesive composition.

The (meth) acrylic polymer (a) may contain other copolymerizable monomer (a 5) as a copolymerization component, if necessary.

Examples of the other copolymerizable monomer (a 5) include aromatic (meth) acrylate monomers such as phenyl (meth) acrylate, benzyl (meth) acrylate, phenoxyethyl (meth) acrylate, phenyl diethylene glycol (meth) acrylate, phenoxypolyethylene glycol-polypropylene glycol- (meth) acrylate, nonylphenol ethylene oxide adduct (meth) acrylate, 4-acryloxybenzophenone, 4-acryloxyethoxybenzophenone, 4-acryloxy4 ' -methoxybenzophenone, 4-acryloxyethoxy-4 ' -methoxybenzophenone, 4-acryloxy4 ' -bromobenzophenone, 4-acryloxyethoxy-4 ' -bromobenzophenone, 4-methacryloxybenzophenone, 4-methacryloxyethoxy-4 ' -methoxybenzophenone, 4-methacryloxyoxy-4 ' -bromobenzophenone, 4-methacryloxyethoxy-4 ' -bromobenzophenone, and a mixture thereof, and the like, and vinyl (meth) acrylate monomers such as those having a structure (meth) such as benzophenone, acrylonitrile, styrene, and the like, vinyl monomers such as vinyl stearate, vinyl chloride, vinylidene chloride, alkyl vinyl ether, vinyl toluene, vinyl pyridine, vinyl pyrrolidone, dialkyl itaconate, dialkyl fumarate, allyl alcohol, acryl chloride, methyl vinyl ketone, N-acrylamidomethyl trimethyl ammonium chloride, allyl trimethyl ammonium chloride, and dimethylallyl vinyl ketone. They may be used alone or in combination of 2 or more.

The (meth) acrylic polymer (a) may have a photoactive site, for example, a polymerizable carbon double bond group introduced into a side chain. Thus, the adhesive composition I can be crosslinked by radical polymerization even if the adhesive composition I does not contain the polyfunctional (meth) acrylate (D).

In addition, the crosslinking sensitivity of the adhesive composition I can be improved, and the adhesive composition I can be crosslinked by irradiation with active energy rays of lower energy, and aggregation force and heat resistance can be imparted.

Examples of the method for introducing a polymerizable carbon double bond group into the side chain of the (meth) acrylic polymer (a) include the following methods: a copolymer comprising the above-mentioned hydroxyl group-containing monomer (a 2) and functional group-containing ethylenically unsaturated monomer (a 4) as copolymerization components is produced, and then, a compound (a 6) having a functional group capable of reacting with the functional groups and a polymerizable carbon double bond group is subjected to condensation or addition reaction in a state where the activity of the polymerizable carbon double bond group is maintained.

Examples of the combination of these functional groups include an epoxy group (glycidyl group) and a carboxyl group, an amino group and an isocyanate group, an epoxy group (glycidyl group) and an amino group, a hydroxyl group and an epoxy group, and a hydroxyl group and an isocyanate group. Among these combinations of functional groups, a combination of hydroxyl groups and isocyanate groups is preferable for ease of reaction control. Among them, a copolymer having a hydroxyl group and the aforementioned compound having an isocyanate group are suitable.

Examples of the isocyanate compound having a polymerizable carbon double bond group include the above-mentioned 2-acryloyloxyethyl isocyanate, 2-methacryloyloxyethyl isocyanate, and alkylene oxide adducts thereof.

The amount of the compound (a 6) to be added is preferably 10 parts by mass or less, more preferably 8 parts by mass or less, further preferably 5 parts by mass or less, and particularly preferably 3 parts by mass or less, per 100 parts by mass of the (meth) acrylic polymer (a) from the viewpoints of adhesion improvement and stress relaxation.

The mass average molecular weight of the (meth) acrylic polymer (a) is preferably 10 ten thousand or more, more preferably 30 ten thousand or more, and still more preferably 50 ten thousand or more, from the viewpoint of obtaining the present adhesive composition I having a high aggregation force.

The upper limit value of the mass average molecular weight of the (meth) acrylic polymer (a) is preferably 200 ten thousand or less, more preferably 150 ten thousand or less, and even more preferably 100 ten thousand or less, from the viewpoint of obtaining the present adhesive composition I having high fluidity and stress relaxation property.

Ultraviolet absorber (B) >)

The adhesive composition I can reduce degradation of the coated polarizing element due to light by containing the ultraviolet absorber (B).

Since the present adhesive composition I contains the ultraviolet absorber (B), it is preferable to cure the adhesive composition by light having a wavelength other than the absorption wavelength of the ultraviolet absorber (B) when the adhesive composition is cured by light.

Examples of the ultraviolet absorber (B) include benzophenone-based ultraviolet absorbers each having a benzophenone structure, benzotriazole-based ultraviolet absorbers each having a benzotriazole structure, triazine-based ultraviolet absorbers each having a triazine structure, salicylic-based ultraviolet absorbers each having a salicylic acid structure, and cyanoacrylate-based ultraviolet absorbers each having a cyanoacrylate structure. These ultraviolet absorbers may be used singly or in combination of 2 or more.

Examples of the benzophenone-based ultraviolet light absorber include 2, 4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-octoxybenzophenone, 2-hydroxy-4-benzyloxy-benzophenone, 2-hydroxy-4-methoxy-5-sulfobenzophenone, 2-hydroxy-4-methoxy-5-sulfoacid trihydrate benzophenone, 2 '-dihydroxy-4-methoxybenzophenone, 2',4 '-tetrahydroxybenzophenone, 2' -dihydroxy-4, 4 '-dimethoxybenzophenone, 2' -dihydroxy-4, 4 '-dimethoxy-5-sodium sulfonate benzophenone, bis (5-benzoyl-4-hydroxy-2-methoxyphenyl) methane, 2-hydroxy-4-n-dodecoxybenzophenone, and 2-hydroxy-4-methoxy-2' -carboxybenzophenone.

Examples of the benzotriazole-based ultraviolet absorber include 2- (2-hydroxy-5-methylphenyl) benzotriazole, 2- (2-hydroxy-5-tert-octylphenyl) benzotriazole, 2- (2-hydroxy-3, 5-dicumylphenyl) phenylbenzotriazole, 2- (2-hydroxy-3-tert-butyl-5-methylphenyl) -5-chlorobenzotriazole, 2' -methylenebis [4- (1, 3-tetramethylbutyl) -6- (2H-benzotriazol-2-yl) phenol ], 2- (2-hydroxy-3, 5-di-tert-butylphenyl) benzotriazole, 2- (2-hydroxy-3, 5-di-tert-butylphenyl) -5-chlorobenzotriazole, 2- (2-hydroxy-3, 5-di-tert-pentylphenyl) benzotriazole, 2- (2-hydroxy-5-tert-octylphenyl) benzotriazole, 2- (2-hydroxy-5-tert-butylphenyl) benzotriazole, 2- (2-hydroxy-4-octylphenyl) benzotriazole, 2' -bis (2-hydroxy-4-octylphenyl) benzotriazole and 2, 6 ' -bis (4-methylphenyl) benzotriazole, 2- [ 2-hydroxy-3- (3, 4,5, 6-tetrahydrophthalimidomethyl) -5-methylphenyl ] benzotriazole, and the like.

Examples of the triazine ultraviolet light absorber include 2- (2-hydroxy-4-methoxyphenyl) -4, 6-diphenyl-1, 3, 5-triazine, 2- (2-hydroxy-4-ethoxyphenyl) -4, 6-diphenyl-1, 3, 5-triazine, 2- (2-hydroxy-4-propoxyphenyl) -4, 6-diphenyl-1, 3, 5-triazine, 2- (2-hydroxy-4-butoxyphenyl) -4, 6-diphenyl-1, 3, 5-triazine, 2- (2-hydroxy-4-hexyloxyphenyl) -4, 6-diphenyl-1, 3, 5-triazine, 2- (2-hydroxy-4-octyloxyphenyl) -4, 6-diphenyl-1, 3, 5-triazine, 2- (2-hydroxy-4-dodecyloxyphenyl) -4, 6-diphenyl-1, 3, 5-triazine, 2- (2-hydroxy-4-benzyloxyphenyl) -4, 6-diphenyl-1, 3, 5-triazine, 2- (2-hydroxy-4-butoxyphenyl) -4, 6-diphenyl-1, 3, 5-triazine, 2- (2-hydroxy-4-hexyloxyphenyl) -4, 6-diphenyl-1, 3, 5-triazine, 2- (2-hydroxy-4-octyloxyphenyl) -4, 6-diphenyl-1, 3, 5-triazine, 2- (2-hydroxy-4-dodecyloxyphenyl) -4, 6-diphenyl-5-triazine, and (2-hydroxy-4-3-butoxyphenyl) -3-hydroxy-3-triazine, 2- (2-hydroxy-4- [ 1-octyloxycarbonylethoxy ] phenyl) -4, 6-bis (4-phenylphenyl) -1,3, 5-triazine, 2- [4- [ (2-hydroxy-3-dodecyloxypropyl) oxy ] -2-hydroxyphenyl ] -4, 6-bis (2, 4-dimethylphenyl) -1,3, 5-triazine, 2- [4- [ (2-hydroxy-3-tridecyloxypropyl) oxy ] -2-hydroxyphenyl ] -4, 6-bis (2, 4-dimethylphenyl) -1,3, 5-triazine, 2- [4- [ (2-hydroxy-3- (2' -ethyl) hexyl) oxy ] -2-hydroxyphenyl ] -4, 6-bis (2, 4-dimethylphenyl) -1,3, 5-triazine, 2, 4-bis (2, 4-dimethylphenyl) -6- [ 2-hydroxy-4- (3-octyloxy-2-hydroxypropyloxy) -5- α -cumylphenyl ] -s-triazine, 2, 4-bis (2, 4-dimethylphenyl) -6- [ 2-hydroxy-4- (3-ethylpropyloxy) -4-nonyloxy) -5- α -cumylphenyl ] -s-triazine, 2, 4-bis (2, 4-dimethylphenyl) -6- [ 2-hydroxy-4- (3-decyloxy-2-hydroxypropyloxy) -5- α -cumylphenyl ] -s-triazine, 2- (2-hydroxy-4-acryloyloxyethoxyphenyl) -4, 6-bis (2, 4-dimethylphenyl) -1,3, 5-triazine, and the like.

Examples of the salicylic acid-based ultraviolet absorber include phenyl salicylate, p-tert-butylphenyl salicylate, and p-octylphenyl salicylate.

Examples of the cyanoacrylate-based ultraviolet absorber include 2-ethylhexyl 2-cyano-3, 3 '-diphenylacrylate and ethyl 2-cyano-3, 3' -diphenylacrylate.

Among them, from the viewpoint of effectively suppressing the light reaching the coated polarizing element, benzophenone-based ultraviolet absorbers, benzotriazole-based ultraviolet absorbers, and triazine-based ultraviolet absorbers are preferable. Among them, a benzophenone-based ultraviolet absorber containing a benzophenone structure is more preferable from the viewpoint of excellent yellowing resistance.

Further, from the viewpoint of blocking light rays in a long wavelength region, a dihydroxybenzophenone-based ultraviolet absorber such as 2, 4-dihydroxybenzophenone, 2' -dihydroxy-4-methoxybenzophenone, 2', 4' -tetrahydroxybenzophenone, 2' -dihydroxy-4, 4' -dimethoxybenzophenone, and 2,2' -dihydroxy-4, 4' -dimethoxy-5-sodium sulfonate benzophenone is more preferable.

The lower limit value of the content of the ultraviolet absorber (B) is preferably 0.1 part by mass or more, more preferably 0.5 part by mass or more, still more preferably 1.5 parts by mass or more, particularly preferably 3 parts by mass or more, particularly preferably 5 parts by mass or more, and most preferably 6 parts by mass or more, relative to 100 parts by mass of the (meth) acrylic polymer (a) from the viewpoint of improving the light resistance reliability.

On the other hand, the upper limit of the content of the ultraviolet absorber (B) is preferably 15 parts by mass or less, more preferably 12 parts by mass or less, further preferably 10 parts by mass or less, particularly preferably 8 parts by mass or less, and most preferably 7 parts by mass or less, per 100 parts by mass of the (meth) acrylic polymer (a), from the viewpoint of suppressing bleeding and improving yellowing resistance.

Radical polymerization initiator (C)

The radical polymerization initiator (C) may be any one that can release a substance that initiates radical polymerization by at least any one of irradiation with active energy rays such as light and heat. In particular, a photoradical polymerization initiator which can initiate a reaction by irradiation with active energy rays such as light is preferable in that curing is not required, and productivity is excellent.

Examples of the thermal radical polymerization initiator include organic peroxides such as hydrogen peroxide and perbenzoic acid, azo compounds such as azobisbutyronitrile, and the like.

On the other hand, photo radical polymerization initiators are roughly classified into 2 types according to a radical generation mechanism, and can be roughly classified into: a photo-cleavage type radical polymerization initiator capable of generating radicals by cleavage and decomposition of a single bond of the photo-radical polymerization initiator itself; the initiator after the light excitation forms an excitation complex with a hydrogen donor in the system, and the hydrogen abstraction type photoradical polymerization initiator can transfer hydrogen of the hydrogen donor.

The photocleavable radical polymerization initiator is decomposed into other compounds when it generates radicals by light irradiation, and once excited, becomes incapable of functioning as a reaction initiator. Therefore, the pressure-sensitive adhesive layer or the pressure-sensitive adhesive sheet after the completion of the crosslinking reaction does not remain as an active material, and there is no possibility of unexpected photodegradation or the like of the pressure-sensitive adhesive layer or the pressure-sensitive adhesive sheet, which is preferable.

On the other hand, the hydrogen abstraction type photo radical polymerization initiator is useful in that it can maintain the function as a reaction initiator even when irradiated with light a plurality of times, and does not generate decomposition products such as a photo-cleavage type radical polymerization initiator when the radical is reacted by irradiation with active energy rays such as ultraviolet rays, and therefore, it is less likely to become volatile after the reaction is completed, and damage to an adherend can be reduced.

Among the above-mentioned photo radical polymerization initiators, the present adhesive composition I preferably selects a photo-cleavage type radical polymerization initiator from the viewpoint of ensuring the photo-reliability of the adhesive layer or the adhesive sheet.

In the case of using a photo radical polymerization initiator, from the viewpoint of avoiding reaction disorder caused by the ultraviolet absorber (B), a visible light initiator which generates radicals by irradiation with visible light, light having wavelengths of at least 390nm, 405nm and 410nm, for example, light having a wavelength range of 380nm to 700nm, and becomes a starting point of the crosslinking reaction of the present adhesive composition I is preferable.

However, the visible light initiator may generate radicals by irradiation with only visible light, or may generate radicals by irradiation with light in a wavelength region other than the visible light region.

Examples of the photocleavable radical polymerization initiator include 2, 2-dimethoxy-1, 2-diphenylethane-1-one, 1-hydroxycyclohexylphenyl ketone, 2-hydroxy-2-methyl-1-phenyl-propan-1-one, 1- (4- (2-hydroxyethoxy) phenyl) -2-hydroxy-2-methyl-1-propan-1-one, 2-hydroxy-1- [4- {4- (2-hydroxy-2-methyl-propionyl) benzyl } phenyl ] -2-methyl-propan-1-one, oligo (2-hydroxy-2-methyl-1- (4- (1-methylvinyl) phenyl) propanone, phenylglyoxylic acid methyl ester, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) butan-1-one, 2-methyl-1- [4- (methylthio) phenyl ] -2-morpholinopropane-1-one, 2- (dimethylamino) -2- [ (4-methylphenyl) methyl) -1- [4- (4-morpholinyl) phenyl ] -1, bis (4, 6-trimethylbutanone, 4-phenylphosphine oxide, 2,4, 6-trimethylbenzoyl diphenyl phosphine oxide, (2, 4, 6-trimethylbenzoyl) ethoxyphenyl phosphine oxide, derivatives thereof, and the like.

Among them, from the viewpoint of decolorization by becoming a decomposition product after the reaction, an acylphosphine oxide-based photoinitiator such as bis (2, 4, 6-trimethylbenzoyl) -phenylphosphine oxide, 2,4, 6-trimethylbenzoyl diphenylphosphine oxide, (2, 4, 6-trimethylbenzoyl) ethoxyphenylphosphine oxide, or bis (2, 6-dimethoxybenzoyl) 2, 4-trimethylpentylphosphine oxide is preferable.

Examples of the hydrogen abstraction type photo radical polymerization initiator include bis (2-phenyl-2-oxoacetic acid) oxybis ethylene ester, methyl phenylglyoxylate, a mixture of 2- [ 2-oxo-2-phenyl-acetoxy-ethoxy ] ethyl oxy-phenyl-acetate and 2- [ 2-hydroxy-ethoxy ] ethyl oxy-phenyl-acetate, thioxanthone, 2-chlorothioxanthone, 3-methylthioxanthone, 2, 4-dimethylthioxanthone, anthraquinone, 2-methylanthraquinone, 2-ethylanthraquinone, 2-t-butylanthraquinone, 2-aminoanthraquinone, camphorquinone, derivatives thereof, and the like.

Among them, any 1 or 2 selected from the group consisting of methyl phenylglyoxylate, a mixture of 2- [ 2-oxo-2-phenyl-acetoxy-ethoxy ] ethyl oxy-phenyl-acetate and 2- [ 2-hydroxy-ethoxy ] ethyl oxy-phenyl-acetate is preferable.

The photo radical polymerization initiator is not limited to the above-listed ones. Any one of the above-listed photo radical polymerization initiators or a derivative thereof may be used, or two or more may be used in combination. The visible light initiator may be mixed with a substance that generates radicals only by irradiation with other light rays such as ultraviolet rays.

A thermal radical polymerization initiator may be used in combination with a photo radical polymerization initiator.

The content of the radical polymerization initiator (C) is not particularly limited, but is preferably 0.1 part by mass or more, more preferably 0.5 part by mass or more, still more preferably 1 part by mass or more, and particularly preferably 2 parts by mass or more, based on 100 parts by mass of the (meth) acrylic polymer (a), from the viewpoint of sufficiently conducting the polymerization reaction and improving the shape stability of the adhesive sheet.

The upper limit of the content of the radical polymerization initiator (C) is preferably 15 parts by mass or less, more preferably 10 parts by mass or less, further preferably 6 parts by mass or less, and particularly preferably 4 parts by mass or less, per 100 parts by mass of the (meth) acrylic polymer (a) from the viewpoint of securing the adhesion.

(multifunctional (meth) acrylate (D))

The present adhesive composition I preferably contains a polyfunctional (meth) acrylate (D) as needed.

The adhesive composition I contains the polyfunctional (meth) acrylate (D), and thus the adhesive composition I forms a crosslinked structure, whereby the adhesive sheet I can be imparted with aggregation force and moderate toughness. In this way, when a coated polarizing element with an adhesive layer described later is produced, it is possible to prevent the adhesive layer from being deformed and broken when the surface of the coated polarizing element is bent or cut.

The polyfunctional (meth) acrylate (D) is a compound or composition forming a crosslinked structure in the present adhesive composition I, and examples thereof include (meth) acrylic monomers having 2 or more functional groups, and (meth) acrylic oligomers.

Examples of the (meth) acrylic monomers include 1, 4-butanediol di (meth) acrylate, glycerol di (meth) acrylate, neopentyl glycol di (meth) acrylate, glycerol glycidyl ether di (meth) acrylate, 1, 6-hexanediol di (meth) acrylate, 1, 9-nonanediol di (meth) acrylate, tricyclodecane dimethanol di (meth) acrylate, bisphenol A polyethoxy di (meth) acrylate, bisphenol A polypropoxy di (meth) acrylate, bisphenol F polyethoxy di (meth) acrylate, ethylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, trimethylol propane trioxyethyl (meth) acrylate, epsilon-caprolactone modified tri (2-hydroxyethyl) isocyanurate tri (meth) acrylate, pentaerythritol tri (meth) acrylate, propoxylated pentaerythritol tri (meth) acrylate, ethoxylated pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, propoxylated pentaerythritol tetra (meth) acrylate, ethoxylated pentaerythritol tetra (meth) acrylate, di (meth) acrylate, polypropylene glycol di (meth) acrylate, and, polytetramethylene glycol di (meth) acrylate, (tris (acryloxyethyl) isocyanurate, dipentaerythritol hexa (meth) acrylate, dipentaerythritol penta (meth) acrylate, tripentaerythritol hexa (meth) acrylate, tripentaerythritol penta (meth) acrylate, neopentyl glycol hydroxypivalate di (meth) acrylate, di (meth) acrylate of epsilon-caprolactone adduct of hydroxypivalate pentanediol, trimethylolpropane tri (meth) acrylate, trimethylolpropane polyethoxy tri (meth) acrylate, ditrimethylolpropane tetra (meth) acrylate, and the like.

Among them, from the viewpoint of imparting moderate toughness to the cured product, (meth) acrylic monomers are preferable, and among them, polyfunctional (meth) acrylic monomers having an alkylene glycol skeleton such as polyethylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, polytetramethylene glycol di (meth) acrylate and the like are more preferable.

The molecular weight of the (meth) acrylic monomer is preferably 200 or more, more preferably 300 or more, still more preferably 400 or more, and particularly preferably 500 or more, from the viewpoint of imparting moderate flexibility to the cured product. The upper limit of the molecular weight is usually 3000 or less, preferably 2000 or less.

Examples of the (meth) acrylic oligomer include polyfunctional (meth) acrylic oligomers such as polyester (meth) acrylate, epoxy (meth) acrylate, urethane (meth) acrylate, and polyether (meth) acrylate.

Among them, urethane (meth) acrylate oligomers are preferable from the viewpoint of imparting moderate toughness to the cured product.

In addition, when the adhesive composition I is cured, a cured product having high toughness, in other words, from the viewpoint of obtaining a cured product having moderate flexibility, the polyfunctional (meth) acrylate (D) is preferably a (meth) acrylic oligomer having a molecular weight of 3000 or more, and among these, polyfunctional (meth) acrylates having a molecular weight of 5000 or more, 8000 or more, 10000 or more are particularly preferable. The upper limit of the molecular weight is usually 100000 or less, preferably 50000 or less.

The content mass of the polyfunctional (meth) acrylate (D) is preferably 1 part by mass or more, more preferably 2 parts by mass or more, still more preferably 5 parts by mass or more, and particularly preferably 10 parts by mass or more relative to 100 parts by mass of the (meth) acrylic polymer (a) from the viewpoint of the shape stability of the adhesive sheet and the durability that can be imparted when a laminate is formed from the adhesive sheet.

The upper limit value of the content mass of the polyfunctional (meth) acrylate (D) is preferably 100 parts by mass or less, more preferably 60 parts by mass or less, further preferably 40 parts by mass or less, and particularly preferably 30 parts by mass or less, per 100 parts by mass of the (meth) acrylic polymer (a) from the viewpoint of securing the adhesion.

< other Components >)

The adhesive composition I may contain various additives such as a tackifying resin, an antioxidant, a light stabilizer, a metal deactivator, an antioxidant, a moisture absorbent, an antirust agent, a silane coupling agent, and inorganic particles as "other components" as necessary.

If necessary, a reaction catalyst such as a tertiary amine compound, a quaternary ammonium compound, and a tin laurate compound may be suitably contained.

< curability >

The adhesive composition I may be cured at one time or may be cured in multiple stages. That is, the resin may be cured with a margin for further curing. In the case of the gel fraction, the gel fraction of the present adhesive composition I may be 60% or more in one-time curing, or may be 20 to 60% in the first-time curing, leaving room for further curing.

For example, in the case where the adhesive composition I has active energy ray curability, after being laminated with an image display device constituent member such as a coating type polarizing element or after forming a laminate with the coating type polarizing element and another image display device constituent member, the adhesive composition I is cured by irradiation with light, and the coating type polarizing element and the other image display device constituent member are more firmly adhered, so that the reliability of the laminate can be improved.

The light source used is preferably ultraviolet rays or visible rays from the viewpoint of suppressing damage to the constituent members of the image display device and controlling the reaction.

The irradiation time and irradiation means are not particularly limited, and it is preferable to irradiate light from the surface opposite to the lamination surface of the image display device constituent member such as the coated polarizing element.

The irradiation energy, irradiation time, irradiation method, and the like of the active energy ray are not particularly limited, as long as the initiator can be activated to polymerize the (meth) acrylate component.

Light transmittance

In the present adhesive composition I, from the viewpoint of preventing photodegradation of the coated polarizing element when the adhesive layer formed from the present adhesive composition I is used in combination with the coated polarizing element, the transmittance at a wavelength of 400nm of the adhesive layer formed from the present adhesive composition I and having a thickness of 50 μm is preferably 50% or less, more preferably 40% or less, further preferably 30% or less, particularly preferably 25% or less.

In addition, in the present adhesive composition I, from the viewpoint of preventing photodegradation of the coated polarizing element when the adhesive layer formed from the present adhesive composition I is used in combination with the coated polarizing element, the transmittance at 380nm of the adhesive layer formed from the present adhesive composition I and having a thickness of 50 μm is preferably less than 20%, more preferably 5% or less, still more preferably 2% or less, and particularly preferably 1% or less.

Further, in the present adhesive composition I, from the viewpoint of securing sufficient image visibility when the adhesive layer formed from the present adhesive composition I is used in an image display device, the transmittance at a wavelength of 430nm of the adhesive layer formed from the present adhesive composition I and having a thickness of 50 μm is preferably 50% or more, more preferably 60% or more, still more preferably 70% or more, particularly preferably 80% or more, and particularly preferably 85% or more.

Adhesive sheet I

The adhesive sheet I for a coated polarizing element (referred to as "present adhesive sheet I") according to one embodiment of the present invention is an adhesive sheet including an adhesive layer I (referred to as "present adhesive layer I") formed using the present adhesive composition I.

The pressure-sensitive adhesive sheet I may be a single layer composed of a pressure-sensitive adhesive layer formed by using the pressure-sensitive adhesive composition I, or may be a multilayer structure of 2 or more layers including layers other than the pressure-sensitive adhesive layer.

When the pressure-sensitive adhesive sheet I has a multilayer structure of 2 or more layers, the composition of the layers other than the layer formed from the pressure-sensitive adhesive composition I is arbitrary. However, for example, when the intermediate layer, the outermost layer, or the innermost layer is formed from a layer other than the present adhesive layer I, the adhesive composition forming the layer other than the present adhesive layer I is also preferably formed from an adhesive composition containing a (meth) acrylic polymer as a main component resin, and more preferably contains the same (meth) acrylic polymer (a) as the main component resin as the present adhesive layer I, from the viewpoint of further improving interlayer adhesiveness. Further, the layers other than the present adhesive layer I more preferably contain a multifunctional (meth) acrylate and a radical polymerization initiator.

When the pressure-sensitive adhesive sheet I has a multilayer structure of 2 or more layers, at least the outermost layer, the innermost layer, or both of the layers are preferably layers corresponding to the pressure-sensitive adhesive layer. All layers may be layers corresponding to the present adhesive layer.

When the pressure-sensitive adhesive sheet I has a multilayer structure of 2 or more layers, the thickness of the layer corresponding to the pressure-sensitive adhesive layer is preferably 10% or more and 100% or less relative to the thickness of the entire pressure-sensitive adhesive sheet I, and more preferably 14% or more and 70% or less, and even more preferably 20% or 50% or less.

(light transmittance)

The pressure-sensitive adhesive layer I or the pressure-sensitive adhesive sheet I preferably has a light transmittance at a wavelength of 400nm of 50% or less, more preferably 40% or less, still more preferably 30% or less, and particularly preferably 25% or less, from the viewpoint of preventing photodegradation of the coated polarizing element when used in combination with the coated polarizing element.

In addition, the pressure-sensitive adhesive layer I or the pressure-sensitive adhesive sheet I preferably has a transmittance at a wavelength of 380nm of less than 20%, more preferably 5% or less, still more preferably 2% or less, and particularly preferably 1% or less, from the viewpoint of preventing photodegradation of the coated polarizing element when used in combination with the coated polarizing element.

In addition, the pressure-sensitive adhesive layer I or the pressure-sensitive adhesive sheet I preferably has a light transmittance at a wavelength of 430nm of 50% or more, more preferably 60% or more, still more preferably 70% or more, particularly preferably 80% or more, and particularly preferably 85% or more, from the viewpoint of securing sufficient image visibility when used in an image display device.

(b value)

The value of b is preferably 10 or less, more preferably 5 or less, even more preferably 3 or less, and particularly preferably 2 or less, from the viewpoint that adverse effects on image quality when used in an image display device can be suppressed.

The value b is a value b in a color space indicated by L x a x b x prescribed in JIS Z8781-4, and means that yellowing increases if it increases on the positive side, bluing increases if it increases on the negative side, and means that it becomes achromatic if it approaches 0.

In the pressure-sensitive adhesive layer I or the pressure-sensitive adhesive sheet I, the type and amount of the ultraviolet absorber are preferably adjusted to an appropriate range in order to adjust the light transmittance at wavelengths of 380nm, 400nm, and 430nm, and the b-value to the above-described ranges. But is not limited to this method.

In addition, the present pressure-sensitive adhesive layer I or the present pressure-sensitive adhesive sheet I preferably satisfies the relationship between the following formulas (I) and (II) in terms of the light transmittance T (380) at a wavelength of 380nm, the light transmittance T (430) at a wavelength of 430nm, and the values b.

0≤T(380)×b*≤50 (I)

70≤T(430)×b*≤220 (II)

The present adhesive layer I or the present adhesive sheet I satisfies the relationships of the above-described formulas (I) and (II), thereby making it possible to simultaneously prevent photodegradation of the coated polarizing element and image visibility of the image display device at a higher level.

From the above point of view, T (380) ×b of the formula (I) is preferably 0 to 50, more preferably 0 to 40, still more preferably 0 to 30, and particularly preferably 0 to 20.

T (430) ×b in the formula (II) is preferably 70 to 220, more preferably 80 or 210 or less, further preferably 90 or more or 200 or less, particularly preferably 100 or more or 190 or less.

(gel fraction)

The adhesive layer I or the adhesive sheet I preferably has a gel fraction of 20% or more when used in adhesion. The gel fraction of 20% or more can provide the adhesive sheet with shape stability and durability when forming a laminate.

From the above viewpoints, the gel fraction of the pressure-sensitive adhesive layer I or the pressure-sensitive adhesive sheet I is more preferably 40% or more, still more preferably 50% or more, and particularly preferably 60% or more.

On the other hand, if the gel fraction is 95% or less, the adherend is a member having a level difference portion on the surface, and the member is free from strain and deformation, and can be filled in every place following the level difference. From the above point of view, it is preferably 95% or less, more preferably 85% or less, still more preferably 80% or less, particularly preferably 75% or less.

In the pressure-sensitive adhesive layer I or the pressure-sensitive adhesive sheet I, in order to adjust the gel fraction in the application to the above range, it is preferable to adjust the composition and molecular weight of the (meth) acrylic polymer (a), the addition amount of the multifunctional (meth) acrylate (D) and the radical polymerization initiator (C), or the intensity of the active energy rays to be irradiated and the cumulative light amount. However, the method is not limited to this method.

(thickness)

The thickness of the pressure-sensitive adhesive layer I or the pressure-sensitive adhesive sheet I is preferably 10 μm or more, more preferably 20 μm or more, still more preferably 30 μm or more, particularly preferably 40 μm or more, from the viewpoint of protecting the coated polarizing element. On the other hand, the upper limit value of the thickness is preferably 175 μm or less, more preferably 120 μm or less, further preferably 80 μm or less, particularly preferably 60 μm or less, from the viewpoint of facilitating the reduction in thickness of the image display device.

Method for producing the adhesive sheet I

Next, a method for producing the adhesive sheet I will be described. However, the following description is an example of a method for producing the adhesive sheet I, and the adhesive sheet I is not limited to the one produced by the above production method.

In the production of the adhesive sheet I, the adhesive composition I is prepared by mixing a predetermined amount of a polyfunctional (meth) acrylate (D) and, if necessary, "other" component in addition to the (meth) acrylic polymer (a), the ultraviolet absorber (B) and the radical polymerization initiator (C), and the adhesive composition I is formed into a sheet, and if necessary, the curable compound is crosslinked, that is, polymerized and cured. However, the method is not limited thereto.

In the preparation of the present adhesive composition I, the above raw materials may be kneaded using a kneading machine capable of temperature adjustment (for example, a single screw extruder, a twin screw extruder, a planetary mixer, a twin screw mixer, a pressure kneader, etc.).

In the case of mixing the various raw materials, the various additives may be blended together with the resin in advance and then supplied to a kneader, or all the raw materials may be melt-mixed in advance and then supplied, or a master batch in which only the additives are pre-concentrated in the resin may be prepared and supplied.

As a method for molding the adhesive composition I into a sheet, a known method, for example, a wet lamination method, a dry lamination method, an extrusion casting method using a T die, an extrusion lamination method, a calendaring method, a inflation method, an injection molding, a liquid injection curing method, or the like can be employed. Among them, in the case of producing a sheet, a wet lamination method, an extrusion casting method, and an extrusion lamination method are suitable.

In the case where the adhesive composition I contains the radical polymerization initiator (C), the cured product can be produced by curing the composition by irradiation with heat and/or active energy rays. In particular, the adhesive sheet I can be produced by irradiating a molded article, for example, a sheet body, with heat and/or active energy rays, which is obtained by molding the adhesive composition I.

Examples of the active energy rays to be irradiated include ionizing radiation such as α rays, β rays, γ rays, neutron beams, and electron beams, ultraviolet rays, and visible rays, and among these, ultraviolet rays and visible rays are preferable from the viewpoints of suppression of damage to components constituting the optical device and control of reaction.

The irradiation energy, irradiation time, irradiation method, and the like of the active energy ray are not particularly limited, as long as the initiator can be activated to polymerize the (meth) acrylate component.

In addition, as another embodiment of the method for producing the adhesive sheet I, the adhesive composition I may be dissolved in an appropriate solvent and applied by various coating methods.

In the case of using the coating method, the present adhesive sheet I can also be obtained by performing heat curing in addition to the above-described irradiation curing with active energy rays.

In the case of coating, the thickness of the present adhesive sheet I can be adjusted according to the coating thickness and the solid content concentration of the coating liquid.

Adhesive composition II

The pressure-sensitive adhesive sheet II for image display device constituent members (referred to as "the present pressure-sensitive adhesive sheet II") according to one embodiment of the present invention is a pressure-sensitive adhesive sheet formed from a pressure-sensitive adhesive composition II (referred to as "the present pressure-sensitive adhesive composition II") containing a (meth) acrylic copolymer (a), a hydroxyl group-containing benzophenone compound (B1), and a radical polymerization initiator (C).

Examples of the "image display device constituting member" of the pressure-sensitive adhesive sheet II for constituting an image display device include a reflecting sheet, a light guide plate, a light source, a diffusion film, a prism sheet, a liquid crystal panel, a retardation plate, a glass substrate, a polarizing plate, an organic EL panel, an electrode, an antireflection film, a color filter, a touch sensor, a glass cover sheet, a plastic cover sheet, and a composite and integrated structure of two or more of them. However, the present invention is not limited to these.

The adhesive composition II may be cured by heat as described later, or may be cured by active energy rays. In particular, curing by active energy rays is preferable in terms of no need for curing and excellent productivity.

The adhesive composition II can be cured in multiple stages as described later.

In addition, in the case of an adhesive sheet containing an ultraviolet absorber when curing by an active energy ray, the ultraviolet absorber prevents curing by an active energy ray, and therefore, it is generally difficult to use an active energy ray curing system, but in the present invention, it is dared to apply, and as a result, a good adhesive sheet can be obtained.

(meth) acrylic Polymer (A) >, and a process for producing the same

The above description of the (meth) acrylic polymer (a) of the present adhesive composition I is cited with respect to the (meth) acrylic polymer (a) of the present adhesive composition II and the content thereof. In this case, the present adhesive composition I was replaced with the present adhesive composition II.

< benzophenone compound (B1) containing hydroxyl group >

The adhesive composition II contains a hydroxyl group-containing benzophenone compound (B1) as an ultraviolet absorber, whereby the light-resistant reliability of the adhesive sheet itself can be ensured and the deterioration caused by light of the constituent members of the image display device can be reduced.

Since the present adhesive composition II contains the hydroxyl group-containing benzophenone compound (B1), it is preferable that the curing is performed by light having a wavelength other than the absorption wavelength of the hydroxyl group-containing benzophenone compound (B1) having ultraviolet absorptivity in the case of performing the photo-curing.

Examples of the hydroxyl-containing benzophenone compound (B1) include 2, 4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-octoxybenzophenone, 2-hydroxy-4-benzyloxy-benzophenone, 2-hydroxy-4-methoxy-5-sulfobenzophenone, 2-hydroxy-4-methoxy-5-sulfoacid trihydrate benzophenone, 2 '-dihydroxy-4-methoxybenzophenone, 2',4 '-tetrahydroxybenzophenone, 2' -dihydroxy-4, 4 '-dimethoxybenzophenone, 2' -dihydroxy-4, 4 '-dimethoxy-5-sodium sulfonate benzophenone, bis (5-benzoyl-4-hydroxy-2-methoxyphenyl) methane, 2-hydroxy-4-n-dodecoxybenzophenone, and 2-hydroxy-4-methoxy-2' -carboxybenzophenone.

Further, from the viewpoint of blocking light rays in a long wavelength region, dihydroxybenzophenone compounds such as 2, 4-dihydroxybenzophenone, 2' -dihydroxy-4-methoxybenzophenone, 2', 4' -tetrahydroxybenzophenone, 2' -dihydroxy-4, 4' -dimethoxybenzophenone, and 2,2' -dihydroxy-4, 4' -dimethoxy-5-sodium sulfonate benzophenone are more preferable.

The lower limit value of the content of the hydroxyl group-containing benzophenone compound (B1) is preferably 0.1 part by mass or more, more preferably 0.5 part by mass or more, still more preferably 1.5 part by mass or more, still more preferably 3 parts by mass or more, still more preferably 5 parts by mass or more, still more preferably 6 parts by mass or more, per 100 parts by mass of the (meth) acrylic polymer (a) from the viewpoint of improving the light resistance reliability.

On the other hand, the upper limit of the content of the hydroxyl group-containing benzophenone compound (B1) is preferably 15 parts by mass or less, more preferably 12 parts by mass or less, still more preferably 10 parts by mass or less, particularly preferably 8 parts by mass or less, and most preferably 7 parts by mass or less, relative to 100 parts by mass of the (meth) acrylic polymer (a), from the viewpoint of suppressing bleeding and improving yellowing resistance.

Radical polymerization initiator (C)

The description of the radical polymerization initiator (C) of the present adhesive composition I is cited with respect to the radical polymerization initiator (C) of the present adhesive composition II and the content thereof. In this case, the present adhesive composition I is replaced with the present adhesive composition II, and the ultraviolet absorber (B) is replaced with the hydroxyl group-containing benzophenone compound (B1).

The radical polymerization initiator (C) of the present adhesive composition II preferably has a maximum absorption at least at a wavelength of 400 to 430nm from the viewpoint of avoiding reaction disorder caused by the hydroxyl group-containing benzophenone compound (B1) and suppressing coloration of the present adhesive sheet II due to the radical polymerization initiator (C) itself.

Maximum absorption refers to the wavelength that shows the maximum absorbance in the absorption spectrum.

In addition, from the viewpoint of ensuring the performance balance between the light-resistant reliability and the shape stability of the present adhesive sheet II itself, the mass ratio of the hydroxyl group-containing benzophenone compound (B1) to the radical polymerization initiator (C) is preferably (B1): (C) =1: 0.05 to 1: 20. more preferably 1:0.1 to 1: 10. further preferably 1:0.3 to 1:2.

(multifunctional (meth) acrylate (D))

The present adhesive composition II preferably contains a polyfunctional (meth) acrylate (D) as needed.

The adhesive composition II contains the polyfunctional (meth) acrylate (D), and thus the adhesive composition II forms a crosslinked structure, whereby the adhesive sheet II can be provided with an aggregation force and a proper toughness. The adhesive sheet II has appropriate toughness, and thus, when an image display device constituent member with an adhesive layer described later is produced, it is possible to prevent the adhesive layer from being deformed and broken when the surface of the image display device constituent member is bent or cut.

The above description of the multifunctional (meth) acrylate (D) of the present adhesive composition I is cited with respect to the multifunctional (meth) acrylate (D) of the present adhesive composition II and the content thereof. In this case, the present adhesive composition I was replaced with the present adhesive composition II.

< other Components >)

The adhesive composition II may contain various additives such as a tackifying resin, an antioxidant, a light stabilizer, a metal deactivator, an antioxidant, a moisture absorbent, an antirust agent, a silane coupling agent, and inorganic particles as "other components" as necessary.

If necessary, a reaction catalyst such as a tertiary amine compound, a quaternary ammonium compound, and a tin laurate compound may be suitably contained.

< curability >

The above description of the curability of the present adhesive composition I is cited for the curability of the present adhesive composition II. In this case, the present adhesive composition I was replaced with the present adhesive composition II.

Light transmittance

In the present adhesive composition II, from the viewpoint of preventing photodegradation of an image display device constituent member when the adhesive layer formed from the present adhesive composition II is used in combination with the image display device constituent member, the transmittance at a wavelength of 400nm of the adhesive layer formed from the present adhesive composition II and having a thickness of 50 μm is preferably less than 30%, more preferably 25% or less, further preferably 22% or less, and particularly preferably 20% or less.

In addition, in the present adhesive composition II, from the viewpoint of preventing photodegradation of an image display device constituent member when the adhesive layer formed from the present adhesive composition II is used in combination with the image display device constituent member, the transmittance at 380nm of the adhesive layer formed from the present adhesive composition II and having a thickness of 50 μm is preferably less than 20%, more preferably 5% or less, still more preferably 2% or less, and particularly preferably 1% or less.

Further, in the present adhesive composition II, from the viewpoint of securing sufficient image visibility when the adhesive layer formed from the present adhesive composition II is used in an image display device, the transmittance at a wavelength of 430nm of the adhesive layer formed from the present adhesive composition II and having a thickness of 50 μm is preferably 50% or more, more preferably 60% or more, still more preferably 70% or more, particularly preferably 80% or more, and particularly preferably 85% or more.

Adhesive sheet II

The pressure-sensitive adhesive sheet II for image display device constituent members (referred to as "the present pressure-sensitive adhesive sheet II") according to one embodiment of the present invention is a pressure-sensitive adhesive sheet including a pressure-sensitive adhesive layer II (referred to as "the present pressure-sensitive adhesive layer II") formed using the present pressure-sensitive adhesive composition II.

The pressure-sensitive adhesive sheet II may be a single layer composed of a pressure-sensitive adhesive layer formed by using the pressure-sensitive adhesive composition II, or may be a multilayer structure of 2 or more layers having layers other than the pressure-sensitive adhesive layer.

When the pressure-sensitive adhesive sheet II has a multilayer structure of 2 or more layers, the composition of the layers other than the layer formed from the pressure-sensitive adhesive composition II is arbitrary. However, for example, when the intermediate layer, the outermost layer, or the innermost layer is formed from a layer other than the present adhesive layer II, the adhesive composition forming the layer other than the present adhesive layer II is also preferably formed from an adhesive composition containing a (meth) acrylic polymer as a main component resin, and more preferably contains the same (meth) acrylic polymer (a) as the main component resin as the present adhesive layer II, from the viewpoint of further improving interlayer adhesiveness. Further, the layers other than the present adhesive layer II more preferably contain a multifunctional (meth) acrylate and a radical polymerization initiator.

When the pressure-sensitive adhesive sheet II has a multilayer structure of 2 or more layers, at least the outermost layer, the innermost layer, or both of the layers are preferably layers corresponding to the pressure-sensitive adhesive layer. All layers may be layers corresponding to the layer II of the present adhesive.

When the pressure-sensitive adhesive sheet II has a multilayer structure of 2 or more layers, the thickness of the layer corresponding to the pressure-sensitive adhesive layer II is preferably 10% or more and 100% or less relative to the thickness of the entire pressure-sensitive adhesive sheet, and more preferably 14% or more and 70% or less, and even more preferably 20% or more and 50% or less.

(light transmittance)

The pressure-sensitive adhesive layer II or the pressure-sensitive adhesive sheet II preferably has a transmittance at a wavelength of 400nm of less than 30%, more preferably 25% or less, still more preferably 22% or less, and particularly preferably 20% or less, from the viewpoint of preventing photodegradation of an image display device constituent member when the pressure-sensitive adhesive layer II or the pressure-sensitive adhesive sheet II is used in combination with the image display device constituent member.

In addition, the pressure-sensitive adhesive layer II or the pressure-sensitive adhesive sheet II preferably has a transmittance at a wavelength of 380nm of less than 20%, more preferably 5% or less, still more preferably 2% or less, and particularly preferably 1% or less, from the viewpoint of preventing photodegradation of the image display device constituent member when the pressure-sensitive adhesive layer II or the pressure-sensitive adhesive sheet II is used in combination with the image display device constituent member.

In addition, the pressure-sensitive adhesive layer II or the pressure-sensitive adhesive sheet II preferably has a light transmittance at a wavelength of 430nm of 50% or more, more preferably 60% or more, still more preferably 70% or more, particularly preferably 80% or more, and particularly preferably 85% or more, from the viewpoint of securing sufficient image visibility when used in an image display device.

(b value)

The value of b is preferably 3.0 or less, more preferably 2.5 or less, even more preferably 2.0 or less, and particularly preferably 1.8 or less, in view of suppressing adverse effects on image quality when used in an image display device.

The value b is a value b in a color space indicated by L x a x b x prescribed in JIS Z8781-4, and means that yellowing increases if it increases on the positive side, bluing increases if it increases on the negative side, and means that it becomes achromatic if it approaches 0.

In addition, the present adhesive layer II or the present adhesive sheet II preferably satisfies the relationship between the following formulas (I) and (II) in terms of the light transmittance T (380) at a wavelength of 380nm, the light transmittance T (430) at a wavelength of 430nm, and b.

0≤T(380)×b*≤50 (I)

70≤T(430)×b*≤220 (II)

The present adhesive layer II or the present adhesive sheet II satisfies the relationship of the above-described formulas (I) and (II), and thus can achieve both prevention of photodegradation of the constituent members of the image display device and image visibility of the image display device at a higher level.

From the above point of view, T (380) ×b of the formula (I) is preferably 0 to 50, more preferably 0 to 40, still more preferably 0 to 30, and particularly preferably 0 to 20.

T (430) ×b in the formula (II) is preferably 70 to 220, more preferably 80 to 210, still more preferably 90 to 200, particularly preferably 100 to 190.

In the pressure-sensitive adhesive layer II or the pressure-sensitive adhesive sheet II, the type and the amount of the hydroxyl group-containing benzophenone compound (B1) to be added are preferably appropriately adjusted in order to adjust the light transmittance at wavelengths of 380nm, 400nm and 430nm and the B-value to the above-mentioned ranges. However, the method is not limited thereto.

(gel fraction)

The above description of the gel fraction of the present adhesive layer I or the present adhesive sheet I is cited for the gel fraction of the present adhesive layer II or the present adhesive sheet II. In this case, the adhesive layer I or the adhesive sheet I is replaced with the adhesive layer II or the adhesive sheet II.

(thickness)

The above description of the thickness of the adhesive layer I or the adhesive sheet I is cited for the thickness of the adhesive layer II or the adhesive sheet II. In this case, the adhesive layer I or the adhesive sheet I is replaced with the adhesive layer II or the adhesive sheet II, and the coated polarizing element is replaced with the constituent member for the image display device.

< method for producing the adhesive sheet II >

The above description of the method for producing the adhesive sheet I is cited for the method for producing the adhesive sheet II. In this case, the present adhesive composition I is replaced with the present adhesive composition II, the present adhesive sheet I is replaced with the present adhesive sheet II, the coated polarizing element is replaced with a structural member for an image display device, and the ultraviolet absorber (B) is replaced with the hydroxyl group-containing benzophenone compound (B1).

Adhesive sheet with release film

The present pressure-sensitive adhesive sheets I and II may be formed into pressure-sensitive adhesive sheets with a release film having a structure in which the present pressure-sensitive adhesive sheets I or II and the release film are laminated (referred to as "pressure-sensitive adhesive sheets with a release film").

For example, a pressure-sensitive adhesive sheet with a release film may be formed by molding a single-layer or multi-layer sheet-like pressure-sensitive adhesive layer containing a layer formed from the pressure-sensitive adhesive composition I or II on a release film (see fig. 6).

As a material of the release film, a known release film can be suitably used.

As a material of the release film, for example, a film such as a polyester film, a polyolefin film, a polycarbonate film, a polystyrene film, an acrylic film, a cellulose triacetate film, a fluororesin film, or the like coated with a silicone resin and subjected to a release treatment, a release paper, or the like can be suitably selected and used.

The film may have an antistatic layer, a hard coat layer, an anchor layer, and the like, and other layers as needed.

In the case where the release films are laminated on both sides of the present adhesive sheet I or II, one release film may have the same laminated structure or material as the other release film, or may have a different laminated structure or material.

The thickness may be the same or different.

In addition, release films having different peeling forces and release films having different thicknesses may be laminated on both sides of the present adhesive sheet I or II.

The thickness of the release film is not particularly limited. Among them, from the viewpoint of workability and handling properties, for example, 12 μm to 250 μm is preferable, 25 μm or more or 200 μm or less, and 38 μm or more or 188 μm or less is more preferable.

The present pressure-sensitive adhesive sheets I and II may be molded by, for example, directly extruding the present resin composition I or II, or by injecting the resin composition into a mold, without using the adherend or the release film as described above.

Further, the present adhesive sheets I and II can be formed by directly filling the present resin composition I or II between constituent members for an image display device as an adherend.

Lamination sheet

A laminate sheet (referred to as "the present laminate sheet") as an example of the embodiment of the present invention includes a resin sheet or a film glass on at least one side of the present adhesive sheet I or II (see fig. 7).

Examples of the resin sheet include resin sheets having one or more resins selected from the group consisting of cycloolefin resins, cellulose triacetate resins, polymethyl methacrylate resins, epoxy resins, polyester resins, and polyimide resins as main component resins.

In this case, the main component resin is a resin having the highest mass ratio among the resins constituting the resin sheet, and is a resin having a mass ratio of 50 mass% or more, 60 mass% or more, 70 mass% or more, 80 mass% or more, 90 mass% or more, or 95 mass% or more (including 100 mass%) among the resins constituting the resin sheet.

Examples of the thin film glass include glass having bending resistance such as ultra-thin plate glass (manufactured by Nitro corporation, G-Leaf).

Coated polarizer with adhesive layer

The adhesive layer-equipped coated polarizing element (referred to as "the adhesive layer-equipped coated polarizing element") as an example of the embodiment of the present invention is a coated polarizing element having an adhesive layer I (referred to as "the adhesive layer I") formed of the adhesive composition I or the adhesive layer of the adhesive sheet I on at least one side of the coated polarizing element.

The coated polarizer with an adhesive layer may be, for example, a coated polarizer-equipped adhesive sheet having a coated polarizer on at least one side of the adhesive sheet I.

The adhesive sheet with a polarizing element can be produced, for example, by the following method: a method of transferring a polarizing element onto the surface of the adhesive sheet I after forming the polarizing element on a substrate having releasability; a method of directly forming the adhesive sheet I on a coated polarizing element; a method of forming a coated polarizing element on the adhesive sheet I; etc.

The adhesive layer-coated polarizing element may be one having an adhesive layer provided on at least one side of the adhesive layer I.

In this case, the adhesive layer I may be directly formed on the coated polarizing element, or the adhesive layer formed of the adhesive composition I may be formed on another substrate and then transferred to the coated polarizing element.

Further, the adhesive layer-attached coated polarizing element may be a structure in which the coated polarizing element and the adhesive layer I or the adhesive sheet I are directly laminated, or may be a structure in which another member is interposed therebetween. They all can enjoy the effects of the present invention.

In this case, examples of the "other member" include a reflective sheet, a light guide plate, a light source, a diffusion film, a prism sheet, a liquid crystal panel, an organic EL panel, an antireflection film, a color filter, a polarizing plate, a retardation plate, a glass substrate, a glass cover sheet, a plastic cover sheet, and a composite and integrated member of two or more of them.

Coated polarizing element

The coated polarizing element is a laminate including a film formed by coating an optically anisotropic composition including a liquid crystal compound as described above. For example, an optically anisotropic layer can be formed by applying an optically anisotropic composition containing a liquid crystal compound to an alignment film formed on a substrate, allowing the optically anisotropic composition to be in an aligned state, and curing the composition in the aligned state. Then, using the optically anisotropic layer with a base material or the optically anisotropic layer peeled from the base material, various optically anisotropic members can be produced. The optically anisotropic member may have an optically anisotropic layer formed of an optically anisotropic composition and an alignment film. Further, the optically anisotropic layer may be provided without an alignment film.

Examples of the liquid crystal compound include polymerizable liquid crystal compounds, polymer liquid crystal compounds, and lyotropic liquid crystal compounds.

The conventional polarizing plate has the following general structure: the adhesive agent is applied to a protective film such as a TAC (cellulose triacetate) film or a polyvinyl alcohol (PVA) film, or an adhesive sheet is laminated.

However, if a polarizing plate using an optically anisotropic layer formed of a coated polarizing element is used, a film can be formed by coating, and therefore, the thickness can be reduced as compared with a conventional polarizing element.

In addition, a conventional retardation plate is generally obtained by stretching a resin sheet of polycarbonate or the like, but if it is excessively thin, breakage of the sheet is likely to occur, and therefore there is a limit in thinning.

However, if a retardation plate having an optically anisotropic layer formed of a coated polarizing element is used, the retardation plate is easier to thin as compared with a conventional stretched sheet, and therefore, the thickness can be reduced.

Such a polarizing plate formed of a coated polarizing element and/or a circularly polarizing plate using a retardation plate is used for an image display device, and thus can contribute to the thinning of the image display device.

Examples of the "substrate" used for forming the coated polarizing element include a resin sheet or glass containing one or more resins selected from the group consisting of polyolefin resins, cyclic polyolefin resins, polyester resins, poly (meth) acrylate resins, cellulose ester resins, polycarbonate resins, and polyimide resins as a main component. The base material may have, as required, other layers such as an antistatic layer, a hard coat layer, an anchor layer, a release layer, an easy-to-adhere layer, a protective layer, a color-impermeable layer, a planarizing layer, and the like.

In order to orient the liquid crystal compound, there may be mentioned a method using an orientation regulating force by an orientation film provided on a substrate, an orientation regulating force by an external field such as an electric field or a magnetic field, and/or a shearing force at the time of coating. The method based on an alignment film is particularly preferable from the viewpoint of obtaining a coated polarizing element exhibiting good optical performance by bringing a polymerizable liquid crystal compound into a highly ordered alignment state.

The alignment film provided on the substrate is a layer having an alignment regulating force for aligning a polymerizable liquid crystal compound described later in a desired direction. The alignment film preferably has solvent resistance which is insoluble when the optically anisotropic composition solution is applied, moderate solution affinity which does not repel the optically anisotropic composition solution, and heat resistance in heating treatment at the time of solvent drying and at the time of liquid crystal alignment.

The alignment film may be subjected to an alignment treatment to control the alignment direction. In this case, examples of the method of alignment treatment include known methods (brushing method, method of forming grooves (fine groove structure) on the surface of the alignment film, method of using polarized ultraviolet light/polarized laser light (photo alignment method), alignment method based on LB film formation, alignment method based on oblique vapor deposition of inorganic substance, and the like) described in pages 226 to 239 of "liquid crystal review" (issued by the charpy company, plain for 12 years, 10 months, 30 days), and the like. The brushing method and the photo-alignment method are particularly preferable from the viewpoint of easy obtaining of a high degree of alignment.

The thickness of the oriented film is usually 10nm to 1000nm, preferably 50nm to 800nm. When the content is within the above range, the sufficient alignment regulating force required for aligning the polymerizable liquid crystal compound and the thinning can be achieved at the same time.

The optically anisotropic composition may be a composition containing, in addition to the liquid crystal compound, a polymerization initiator, a polymerization inhibitor, a polymerization auxiliary agent, a polymerizable non-liquid crystal compound, a surfactant, a leveling agent, a coupling agent, a pH adjuster, a dispersant, an antioxidant, an organic/inorganic filler, a metal oxide or other various additives, and a solvent, as required, and the cured layer of the composition exhibits an optical function as a polarizing element.

When the polarizing element is a polarizing film, it is preferable that the optically anisotropic composition contains a dichroic dye. Examples of the dichroic dye include iodine and a dichroic organic dye, and the dichroic dye used may be one type or a combination of a plurality of different dyes.

The dichroic organic dye is not particularly limited, and examples thereof include azo pigments, quinone pigments (including naphthoquinone pigments, anthraquinone pigments, and the like), stilbene pigments, cyanine pigments, phthalocyanine pigments, indigo pigments, condensed polycyclic pigments (including perylene pigments, oxazine pigments, and acridine pigments, and the like), and the like. Among these pigments, azo pigments are preferable because they have a large ratio of molecular length to axis and exhibit excellent dichroism.

(polymerizable liquid Crystal Compound)

The polymerizable liquid crystal compound has both the property of being a polymerizable monomer and the property of being a liquid crystal, and therefore, the polymerizable functional group is crosslinked in a state in which the liquid crystal is aligned, and thus the alignment can be fixed, and the optical anisotropy is exhibited. The polymerizable liquid crystal compound to be used may be one type, or may be a combination of a plurality of different structures.

The polymerizable liquid crystal compound may be any of a low molecular liquid crystal compound having a polymerizable functional group and a high molecular liquid crystal compound having a polymerizable functional group. Among them, the polymerizable liquid crystal compound tends to easily obtain a cured product exhibiting high alignment properties, and therefore, a low-molecular liquid crystal compound is preferable.

The liquid crystal phase shown by the polymerizable liquid crystal compound may be suitably selected from nematic liquid crystal, smectic liquid crystal, cholesteric liquid crystal, discotic liquid crystal and the like, but from the viewpoint of ease of production and obtaining an alignment state with high order, nematic liquid crystal and smectic liquid crystal are preferable.

The polymerizable functional group is preferably a photopolymerizable group for ease of immobilization of the orientation structure. Specifically, examples thereof include an acryl group, a methacryl group, an acryloyloxy group, a methacryloyloxy group, an acryloylamino group, a methacryloylamino group, a vinyl group, a vinyloxy group, an ethynyl group, an ethynyloxy group, a 1, 3-butadienyl group, a 1, 3-butadienyloxy group, an oxiranyl group, an oxetanyl group, a glycidyl group, a glycidyloxy group, a styryl group, and a styryloxy group. Among them, (meth) acryl is preferable.

As the polymerizable liquid crystal compound, a liquid crystal compound having a polymerizable group can be used, in particular, without specifying a molecular structure. For example, the polymerizable liquid crystal compound contained in the optically anisotropic composition includes a compound represented by the following formula (1) (hereinafter, sometimes referred to as "polymerizable liquid crystal compound (1)").

Q ¹ -R ¹ -A ¹¹ -Y ¹ -A ¹² -(Y ² -A ¹³ ) _k -R ² -Q ² ···(1)

(in the formula (1),

-Q ¹ represents a hydrogen atom or a polymerizable group;

-Q ² represents a polymerizable group;

-R ¹ -and R ² -each independently represents a chain-like organic group;

-A ¹¹ -and A ¹³ -each independently represents a partial structure represented by the following formula (2), a 2-valent organic group, or a single bond;

-A ¹² -represents a partial structure represented by the following formula (2) or a 2-valent organic group;

-Y ¹ -and Y ² -each independently represents a single bond, -C (=o) O-, -OC (=o) -, -C (=s) O-, -OC (=s) -, -C (=o) S-, -SC (=o) -, -CH ₂ CH ₂ -、-CH＝CH-、-C≡C-、-C(＝O)NH-、-NHC(＝O)-、-CH ₂ O-、-OCH ₂ -、-CH ₂ S-, or SCH ₂ -；

-A ¹¹ -and A ¹³ One of them is a partial structure represented by the following formula (2) or a 2-valent organic group;

k is 1 or 2.

In the case where k is 2, 2-Y ² -A ¹³ Which may be the same as or different from each other. )

-Cy-X ² -C≡C-X ¹ -···(2)

(in the formula (2),

-Cy-represents a hydrocarbon or heterocyclic group;

-X ¹ -represent-C (=o) O-, -OC (=o) -, -C (=s) O-, -OC (=s) -, -C (=o) S-, -SC (=o) -, -CH ₂ CH ₂ -、-CH＝CH-、-C(＝O)NH-、-NHC(＝O)-、-CH ₂ O-、-OCH ₂ -、-CH ₂ S-, or-SCH ₂ -；

-X ² -represents a single bond, -C (=o) O-, -OC (=o) -, -C (=s) O-, -OC (=s) -, -C (=o) S-, -SC (=o) -, -CH ₂ CH ₂ -、-CH＝CH-、-C(＝O)NH-、-NHC(＝O)-、-CH ₂ O-、-OCH ₂ -、-CH ₂ S-, or-SCH ₂ -。)

Incidentally, -A ¹¹ In the case of the partial structure represented by formula (2), formula (1) may be represented by formula (1A) or formula (1B).

Q ¹ -R ¹ -Cy-X ² -C≡C-X ¹ -Y ¹ -A ¹² -(Y ² -A ¹³ ) _k -R ² -Q ² ···(1A)

Q ¹ -R ¹ -X ¹ -C≡C-X ² -Cy-Y ¹ -A ¹² -(Y ² -A ¹³ ) _k -R ² -Q ² ···(1B)

In addition, -A ¹² In the case of the partial structure represented by formula (2), formula (1) may be represented by formula (1C) or formula (1D).

Q ¹ -R ¹ -A ¹¹ -Y ¹ -Cy-X ² -C≡C-X ¹ -(Y ² -A ¹³ ) _k -R ² -Q ² ···(1C)

Q ¹ -R ¹ -A ¹¹ -Y ¹ -X ¹ -C≡C-X ² -Cy-(Y ² -A ¹³ ) _k -R ² -Q ² ···(1D)

In addition, -A ¹³ In the case of the partial structure represented by formula (2), formula (1) may be represented by formula (1E) or formula (1F).

Q ¹ -R ¹ -A ¹¹ -Y ¹ -A ¹² -(Y ² -Cy-X ² -C≡C-X ¹ ) _k -R ² -Q ² ···(1E)

Q ¹ -R ¹ -A ¹¹ -Y ¹ -A ¹² -(Y ² -X ¹ -C≡C-X ² -Cy) _k -R ² -Q ² ···(1F)

similarly-A ¹¹ -、-A ¹² -, and-A ¹³ In the case where two or more of them are the partial structures represented by the formula (2), the orientations of the partial structures represented by the formula (2) may be reversed independently of each other.

In addition, as described above,A ¹¹ -、-A ¹² -, and-A ¹³ -each independently is a partial structure represented by formula (2) or a 2-valent organic group, furthermore, -a ¹¹ -and A ¹³ -may be a single bond, but-A ¹¹ -and-A ¹³ Not all single bonds.

The polymerizable liquid crystal compound (1) is preferably a compound represented by the above formula (1A), (1B), (1E) or (1F) for the reason of the tendency to obtain high alignment properties.

When the polymerizable liquid crystal compound is photopolymerized, the optically anisotropic composition preferably contains a photopolymerization initiator. The photopolymerization initiator may be any known one.

The thickness of the cured film of the optically anisotropic composition is preferably 100nm or more, more preferably 300nm or more, and still more preferably 1 μm or more from the viewpoint of securing optical functions.

On the other hand, the upper limit of the thickness is preferably 50 μm or less, more preferably 10 μm or less, and still more preferably 5 μm or less, from the viewpoint of facilitating the thinning of the image display device.

A cover layer, an antistatic layer, a hard coat layer, an anchor layer, a release layer, an easy-to-adhere layer, a protective layer, a color-blocking layer, a planarizing layer, and the like, as needed, may be formed on the cured film of the optically anisotropic composition.

Adhesive sheet with polarizing element

The adhesive sheet with a polarizing element (referred to as "adhesive sheet with a polarizing element") as an example of the embodiment of the present invention has a structure in which the adhesive sheet I is provided on at least one side of the coated polarizing element, in other words, the adhesive sheet I is provided with the coated polarizing element on at least one side of the adhesive sheet I.

The adhesive sheet with a polarizing element can be obtained, for example, by the following method: a method of forming a polarizing element on a releasable substrate and then transferring the polarizing element to the surface of the adhesive sheet I; a method of directly forming the adhesive sheet I on a coated polarizing element; a method of forming a coated polarizing element after forming the adhesive sheet I; etc.

The adhesive sheet with a polarizing element may be a structure in which a coated polarizing element and the adhesive sheet I are directly laminated, or may be a structure in which other members are interposed therebetween. The effects of the present invention can be enjoyed in any case.

In this case, examples of the "other member" include a reflective sheet, a light guide plate, a light source, a diffusion film, a prism sheet, a liquid crystal panel, an organic EL panel, an antireflection film, a color filter, a polarizing plate, a retardation plate, a glass substrate, a glass cover sheet, a plastic cover sheet, or a composite and integrated structure of two or more of them, which is the "other image display device constituent member".

The coated polarizing element of the adhesive sheet with a polarizing element is similar to the coated polarizing element of the coated polarizing element with an adhesive layer.

Image display device structure with adhesive layer

An image display device constituent member with an adhesive layer (referred to as "the image display device constituent member with an adhesive layer") as an example of the embodiment of the present invention is an image display device constituent member with an adhesive layer II (referred to as "the adhesive layer II") formed of the adhesive composition II or an adhesive layer provided with the adhesive sheet on at least one side of the image display device constituent member.

The image display device constituent member with an adhesive layer may be, for example, an adhesive sheet with an image display device constituent member provided on at least one side of the adhesive sheet II.

The image display device constituent member with an adhesive layer may be an image display device constituent member with an adhesive layer including an image display device constituent member on at least one side of the adhesive layer II.

In this case, the adhesive layer II may be directly applied to the image display device constituent member, or the adhesive layer formed of the adhesive composition II may be formed on another substrate and then transferred to the image display device constituent member.

Further, the image display device constituent member with an adhesive layer may be a structure in which the image display device constituent member and the adhesive layer II or the adhesive sheet II are directly laminated, or may be a structure in which another member is interposed therebetween. The effects of the present invention can be enjoyed in any case.

In this case, examples of the "other member" include a reflection sheet, a light guide plate, a light source, a diffusion film, a prism sheet, a liquid crystal panel, a phase difference plate, a glass substrate, a polarizing plate, an organic EL panel, an electrode, an antireflection film, a color filter, a touch sensor, a glass cover sheet, a plastic cover sheet, and a composite and integrated member of two or more of them.

In addition to the above-described members, other layers such as an antistatic layer, a hard coat layer, an anchor layer, a release layer, an easy-to-adhere layer, a protective layer, a color-impermeable layer, and a planarizing layer may be interposed as needed.

Image display device constituent Member Using coated polarizing element

As an example of the image display device constituent member, an optical member using a coated polarizing element can be given.

The foregoing description of the coated polarizing element in the coated polarizing element with an adhesive layer is cited as the coated polarizing element. In this case, the description of the polymerizable liquid crystal compound in this description is also cited.

Adhesive sheet for forming member of image display device of this band

An adhesive sheet with an image display device constituent member (referred to as "adhesive sheet with a self-adhesive image display device constituent member") as an example of an embodiment of the present invention is a structure in which the self-adhesive sheet II is provided on at least one side of the image display device constituent member.

The pressure-sensitive adhesive sheet of the present image display device constituent member can be obtained, for example, by the following method: a method of forming an image display device constituent member on a substrate having releasability and then transferring the image display device constituent member to the surface of the adhesive sheet II; a method of directly molding the adhesive sheet on an image display device constituent member; a method of forming the image display device constituent member on the present adhesive sheet II; etc.

Further, the pressure-sensitive adhesive sheet with the image display device constituent member may be a structure in which the image display device constituent member and the pressure-sensitive adhesive sheet are directly laminated, or may be a structure in which another member is interposed therebetween. The effects of the present invention can be enjoyed in any case.

In this case, examples of the "other member" include a reflective sheet, a light guide plate, a light source, a diffusion film, a prism sheet, a liquid crystal panel, a retardation plate, a glass substrate, a polarizing plate, an organic EL panel, an electrode, an antireflection film, a color filter, a touch sensor, a glass cover sheet, a plastic cover sheet, and a composite and integrated member of two or more of them.

The image display device constituent member of the adhesive sheet with an image display device constituent member is the same as the image display device constituent member of the image display device constituent member with an adhesive layer.

Image display device

An image display device (referred to as "the present image display device") according to an example of the embodiment of the present invention is an image display device including the present adhesive layer I or II.

The present adhesive layer I or II is not limited to the form thereof, and may be a sheet-like adhesive article formed into a sheet shape in advance, that is, the present adhesive sheet I or II.

As an example of the image display device, there is an image display device having a structure in which the adhesive layer I or II formed of the adhesive composition I or II, the coating type polarizing element or the image display device constituent member, and, if necessary, other members such as other image display device constituent members are combined and laminated.

The image display device may be configured by directly laminating the coating type polarizing element or the image display device constituent member and the adhesive layer I or II as shown in fig. 2 or 4, or may be configured by sandwiching another member, for example, another image display device constituent member, between them as shown in fig. 3. The effects of the present invention can be enjoyed in any case.

In this case, examples of the "other image display device constituent member" include a reflective sheet, a light guide plate, a light source, a diffusion film, a prism sheet, a laminate, a liquid crystal panel, a retardation plate, a glass substrate, a polarizing plate, an organic EL panel, an electrode, an antireflection film, a color filter, a touch sensor, a glass cover sheet, a plastic cover sheet, or a composite and integrated member of two or more of them.

In addition to the above-described members, other layers such as an antistatic layer, a hard coat layer, an anchor layer, a release layer, an easy-to-adhere layer, a protective layer, a color-impermeable layer, and a planarizing layer may be interposed as needed.

The adhesive layers I and II in the present image display device are preferably arranged on the visible side of the coated polarizing element as an adherend or the image display device constituent member. Specifically, the present adhesive layer I or II is preferably used for bonding a cover glass or a plastic cover glass. Thus, deterioration of the polarizing element or the constituent member of the image display device due to incident light from the outside can be suppressed.

In the case of an organic EL display device (see fig. 5) including the adhesive layer II, when the organic EL panel is configured by integrating a color filter, a black matrix, and an antireflection layer as needed (color filter-incorporated organic EL panel), the adhesive layer II or the adhesive sheet II is preferably disposed on the visible side of the organic EL panel.

Since the color filter-built-in organic EL panel can reduce external light reflection by the color filter, the black matrix, and the antireflection layer built in the panel, a polarizing plate and a phase difference plate (circular polarizing plate) used in the conventional organic EL panel are not required, and further thinning and weight saving of the image display device are facilitated.

Further, the color filter-built-in organic EL panel does not cause light emission loss because the circularly polarizing plate absorbs the light emitted from the organic EL element, and therefore, the light emission efficiency of the organic EL element is significantly improved, and further, the light emission lifetime of the organic EL element is improved, which is advantageous for further improving the performance of the image display device.

The adhesive layer II or the adhesive sheet II is disposed on the visible side of the organic EL panel, so that deterioration of the organic EL panel due to incident light from the outside can be suppressed.

Specific examples of the present image display device include a liquid crystal display, an organic EL display, an inorganic EL display, electronic paper, a plasma display, and a microelectromechanical system (MEMS) display.

The laminate sheet may be used for the surface of a cover glass or a plastic cover glass of the image display device.

The adhesive layer I or II has the above light transmittance, b-value, gel fraction, and thickness characteristics similarly to the adhesive sheet I or II, and can enjoy the preferable ranges of the respective characteristics shown in the adhesive sheet I or II.

Description of the terms

In the present invention, when the term "X to Y" (X, Y is any number), the term "X or more and Y or less" is included, and the term "preferably greater than X" or "preferably less than Y" is also included, unless otherwise specified.

In addition, the meaning of "preferably greater than X" or "preferably lower than Y" is also included in the case where the meaning is expressed as "X or greater than X" (X is an arbitrary number) or "Y or less" (Y is an arbitrary number).

In addition, "sheet" in the present invention conceptually includes a tablet, a film, a tape.

Examples

Hereinafter, the present invention will be described in further detail with reference to examples and comparative examples. However, the present invention is not limited to these examples.

Description of raw materials

In the following examples and comparative examples, raw materials used in the preparation of the adhesive composition are described.

[ (meth) acrylic Polymer (A) ]

(meth) acrylic polymer (A-1): to contain 2-ethylhexyl acrylate: 67 mass% methyl acrylate: 5 mass%, ethyl acrylate: 10 mass%, 2-hydroxyethyl acrylate: 14 mass%, 4-hydroxybutyl acrylate: 4% by mass of an acrylic copolymer polymer, and the mass average molecular weight (Mw) of the aforementioned acrylic copolymer polymer was 700000 as measured on the basis of GPC.

(meth) acrylic polymer (A-2): for the copolymer of butyl acrylate: 85 mass%, 2-hydroxyethyl acrylate: 15% by mass of a copolymer of 100 parts by mass, 0.06 parts by mass of 2-methacryloyloxyethyl isocyanate was reacted in an ethyl acetate solution to give an acrylic copolymer polymer having a side chain having a polymerizable carbon double bond group introduced thereto, and the acrylic copolymer polymer had a mass average molecular weight (Mw) of 900000 as measured by GPC.

[ ultraviolet absorber (B) ]

Ultraviolet absorber (B-1): 2,2' -dihydroxy-4-methoxybenzophenone (manufactured by CHEMIPRO KASEI KAISHA, LTD., KEMISORB 111)

Ultraviolet absorber (B-2): 2,2', 4' -tetrahydroxybenzophenone (manufactured by SHIPRO KASEI KAISHA, LTD., SEESORB 106)

Ultraviolet absorber (B-3): 2- (5-chloro-2H-benzotriazol-2-yl) -4-methyl-6-tert-butylphenol (Tinuvin 326 manufactured by BASF corporation)

Benzophenone compound (B1-1) containing a hydroxyl group: 2,2' -dihydroxy-4-methoxybenzophenone (manufactured by CHEMIPRO KASEI KAISHA, LTD., KEMISORB 111)

Benzophenone compound (B1-2) containing a hydroxyl group: 2,2', 4' -tetrahydroxybenzophenone (manufactured by SHIPRO KASEI KAISHA, LTD., SEESORB 106)

[ radical polymerization initiator (C) ]

Photo-cleavage type radical polymerization initiator (C-1): 2,4, 6-trimethylbenzoyl diphenylphosphine oxide (Omnirad TPO H, manufactured by IGM Resins Co., ltd.)

[ multifunctional (meth) acrylate (D) ]

Multifunctional (meth) acrylate (D-1): polypropylene glycol #700 diacrylate (APG-700, molecular weight: 823, manufactured by Xinzhongcun chemical Co., ltd.)

Multifunctional (meth) acrylate (D-2): difunctional urethane acrylate (Mitsubishi chemical Co., ltd., violet UV-3700B, molecular weight: 38000)

[ others ]

Solvent: acetic acid ethyl ester

Silane coupling agent: 3-epoxypropoxypropyl methyl diethoxysilane (Xinyue silicone made, KBM 403)

Rust inhibitor: 1,2, 3-triazole

Production of coated polarizing element (image display component)

A coated polarizing element as an image display component used in the evaluation, and a polymerizable liquid crystal compound and a pigment contained in the coated polarizing element will be described.

(Synthesis of polymerizable liquid Crystal Compound)

[ liquid Crystal Compound (I-1) ]

According to Japanese patent application laid-open No. 2020-042305, a liquid crystal compound (I-1) represented by the following formula (I-1) is synthesized.

(Synthesis of pigment)

[ pigment (II-1) ]

The pigment (II-1) represented by the following formula (II-1) was synthesized by the synthesis method described below.

Synthesis of (II-1-a):

into an ice-cooled reactor, tetrahydrofuran (100 mL), sodium hydride (purity: 60%, 6.7g,168.0 mmol) and a mixture of diethyl (4-nitrobenzyl) phosphonate (18.0 g,65.9 mmol), 4-butylbenzaldehyde (9.1 g,56.1 mmol) and tetrahydrofuran (50 mL) were added dropwise over 10 minutes, and after washing with tetrahydrofuran (30 mL), the mixture was stirred at 50℃for 0.5 hours. The reaction solution was poured into water, extracted with ethyl acetate, washed with water and saturated brine, and the solvent was distilled off. After the obtained crude body was dissolved in ethyl acetate (20 mL) by heating, hexane (50 mL) was added and cooled, and the precipitated precipitate was filtered off, washed with hexane and dried under reduced pressure to obtain 15.0g of (II-1-a).

Synthesis of (II-1-b):

(II-1-a) (15.0 g,53.3 mmol), tetrahydrofuran (150 mL), iron powder (13.9 g,248.9 mmol) were mixed, and ammonium chloride (13.3 g,248.6 mmol) dissolved in water (30 mL) was added dropwise thereto and stirred at 50℃for 3 hours. The mixture was filtered through celite, extracted with ethyl acetate, washed with water and saturated brine, and the solvent was distilled off. The obtained crude body was suspended with hexane, and the precipitate was filtered off, washed with hexane and dried to obtain (II-1-b) 10.9g.

Synthesis of (II-1):

(II-1-b) (2.51 g,10.0 mmol), N-methylpyrrolidone (40 mL), concentrated hydrochloric acid (2.2 mL), and water (20 mL) were mixed, cooled to 3℃and then sodium nitrite (789 mg,11.4 mmol) was added thereto, followed by stirring at 15℃for 3.5 hours.

1-phenylpyrrolidine (1.47 g,10.0 mmol), methanol (60 mL), and water (30 mL) were mixed and the pH was adjusted to 3.5 with concentrated hydrochloric acid. An aqueous sodium hydroxide solution was added thereto, and a liquid containing the diazonium salt was added dropwise while maintaining the pH at 3 to 5, followed by stirring at 15℃for 3 hours.

The resulting precipitate was filtered, washed with water and dried under reduced pressure. The obtained crude body was purified by silica gel column chromatography (hexane/methylene chloride) to obtain 3.06g of pigment (II-1) as a red solid.

[ pigment (II-2) ]

The pigment (II-2) represented by the following formula (II-2) was synthesized by the synthesis method described below.

Synthesis of (II-2):

(II-1-b) (1.0 g,4.0 mmol) and N-methylpyrrolidone (13 mL) were mixed, concentrated hydrochloric acid (1.0 g,10.0 mmol) was added thereto, and after cooling in an ice bath, sodium nitrite (0.3 g,4.4 mmol) dissolved in water (1.3 mL) was added thereto and stirred for 1 hour. The reaction mixture was coupled with 1-phenylpiperidine (0.6 g,4.0 mmol) dissolved in methanol (25 mL) and water (6.5 mL) at ph=7, and the precipitate was filtered off, washed with water and dried under reduced pressure. The obtained crude body was purified by silica gel column chromatography (hexane/dichloromethane) to obtain 760mg of pigment (II-2) as an orange solid.

The chemical structures of the liquid crystal compound and the dye synthesized in the above are shown below. In the formula, C ₁₁ H ₂₂ The methylene chain is bonded to 11 in a straight chain.

The chemical structures of the dye (II-3) and the dye (II-4) used in examples and comparative examples are shown below.

(preparation of optically Anisotropic composition)

To 69.31 parts of cyclopentanone were added 28.57 parts of a liquid crystal compound (I-1), 0.10 parts of a pigment (II-1), 0.43 parts of a pigment (II-2), 0.39 parts of a pigment (II-3) (manufactured by Kagaku Kogyo Co., ltd.), 0.90 parts of a pigment (II-4) (manufactured by Showa chemical Co., ltd.), 0.23 parts of the following initiator (PI-1), and 0.34 parts of BYK-361N (manufactured by BYK-Chemie Co., ltd.) and the mixture was heated and stirred at 80℃and then filtered using a syringe having a syringe filter (manufactured by Membrane Solutions Co., PTFE13045, caliber of 0.45 μm), thereby obtaining an optically anisotropic composition.

(production of coated polarizing element)

Orientation with polyimide formed on glassThe optically anisotropic composition prepared above was formed into a film by spin coating on a substrate on which an alignment film was formed by brush polishing, manufactured by LX1400, hitachi Chemical DuPont MicroSystems, ltd., and cooled to a liquid crystal phase after drying at 120 ℃ for 2 minutes, and exposed to 500mJ/cm ² (365 nm basis) to obtain a coated polarizing element having a thickness of about 3. Mu.m.

Further, a coating layer is further provided on the coated polarizing element by using a coating composition in the following manner.

The curable (meth) acryl copolymer (R-1) contained in the composition for covering was synthesized in the following manner.

Into a flask equipped with a thermometer, a stirrer and a reflux condenser, propylene glycol monomethyl ether (157 parts by mass), glycidyl methacrylate (98 parts by mass), methacrylic acid ester (1.0 parts by mass), ethyl acrylate (1.0 parts by mass), 2' -azobis (2, 4-dimethylvaleronitrile) (1.0 parts by mass) and 1.9 parts by mass of gamma-trimethoxysilylpropanethiol (KBM-803 manufactured by Xinyue chemical industries, ltd.) were charged and reacted at 65℃for 3 hours.

After that, 2' -azobis (2, 4-dimethylvaleronitrile) (0.5 mass part) was further added thereto, and after 3 hours of reaction, propylene glycol monomethyl ether (138 mass parts) and p-methoxyphenol (0.45 mass parts) were added thereto, and the mixture was heated to 100 ℃.

Subsequently, acrylic acid (51 parts by mass) and triphenylphosphine (3.1 parts by mass) were added and reacted at 110℃for 6 hours to obtain a (meth) acryl copolymer (R-1) having a carbon-carbon double bond amount (acryl equivalent (acryl introduced)) of 4.6 mmol/g. The mass average molecular weight (Mw) was 17700.

23.08 parts of a 65% propylene glycol monomethyl ether solution of a curable (meth) acryl copolymer (R-1), 0.13 part of a photopolymerization initiator (PI-2) described below, 0.40 part of BYK-3550 (BYK-Chemie Co., ltd.) and 76.39 parts of ethanol were mixed and stirred to obtain a composition for covering.

The coating composition was formed into a film on the coated polarizing element by spin coating, and after drying at 50℃for 2 minutes, the film was exposed to 500mJ/cm ² (365 nm basis) polymerization is carried out, after whichThe coated polarizing element with a coating layer was obtained by laminating a coating layer having a thickness of about 5 μm by heating at 80℃for 5 minutes.

The obtained coated polarizing element with the protective layer was turned while blocking the polarizing plate on the market, and as a result, light and shade were produced, and it was confirmed that the coated polarizing element was capable of being used as a polarizing film.

Example I-1

200 parts by mass of a (meth) acrylic polymer (A-1) solution (dilution solvent: ethyl acetate solid content: 50% by mass), 6 parts by mass of an ultraviolet absorber (B-1), 3 parts by mass of a photo-cleavage type radical polymerization initiator (C-1), 25 parts by mass of a multifunctional (meth) acrylate (D-1), 0.3 part by mass of 3-glycidoxypropyl methyl diethoxysilane (believed to be a silicone system, KBM 403) as a silane coupling agent, 0.3 part by mass of 1,2, 3-triazole as an anti-rust agent, and 101 parts by mass of ethyl acetate were uniformly mixed to prepare an adhesive composition I-1.

On a release film (DIAFOIL MRV, manufactured by Mitsubishi chemical corporation) having a thickness of 100 μm subjected to the silicone release treatment, the adhesive composition I-1 was spread into a sheet so that the thickness of the adhesive composition I-1 after the solvent drying became 50 μm.

Then, the sheet-like adhesive composition I-1 was put into a dryer heated to 95℃together with a release film, and kept for 10 minutes, to volatilize the solvent contained in the adhesive composition I-1.

Further, a release film (DIAFOIL MRQ, manufactured by Mitsubishi chemical corporation) having a thickness of 75 μm was laminated on the sheet-like adhesive composition I-1, which had been subjected to the silicone release treatment, to form a laminate, and the adhesive composition I-1 was subjected to a high-pressure mercury lamp through the release film to give a cumulative irradiation amount of 1000mJ/cm at a wavelength of 365nm ² The cumulative irradiation amount at a wavelength of 405nm was 1400mJ/cm ² The above was irradiated with light to obtain a release film-attached pressure-sensitive adhesive sheet I-1 (pressure-sensitive adhesive sheet thickness: 50 μm) having release films laminated on both front and back sides.

Examples I-2 to I-4 and comparative examples I-1 to I-2

Adhesive compositions I-2 to I-6 and release film-equipped adhesive sheets I-2 to I-6 were produced in the same manner as in example I-1 except that the types and the amounts of the (meth) acrylic polymer (A), the ultraviolet absorber (B), the radical polymerization initiator (C), the multifunctional (meth) acrylate (D) and the other additives used were as shown in Table 1.

< evaluation >

The adhesive compositions I-1 to I-6 and the adhesive sheets I-1 to I-6 obtained in the examples and comparative examples were measured and evaluated as follows.

[ light transmittance ]

The release films on both sides of the release film-equipped adhesive sheets produced in examples and comparative examples were peeled off in order, the adhesive sheets (thickness: 50 μm) were attached so as to be sandwiched between 2 soda lime glass sheets (thickness: 0.5 mm), and autoclave treatment (60 ℃ C., gauge pressure: 0.2MPa, 20 minutes) was performed to carry out finish adhesion, thereby producing samples for evaluation of optical characteristics.

The transmittance of the prepared sample for evaluating optical characteristics was measured in the wavelength region of 360 to 430nm by a spectrophotometer (manufactured by Shimadzu corporation; apparatus name "UV 2450").

[ b value ]

The b-value of the prepared sample for evaluating optical characteristics was measured by a spectrocolorimeter (Suga Test Instruments co., ltd., manufactured by ltd., apparatus name "SC-P") according to JIS Z8781-4.

[ gel fraction ]

The gel fractions of the adhesive compositions prepared in the middle of examples and comparative examples were measured according to the following procedure.

1) The adhesive composition (W1) was weighed and coated on SUS mesh (W0) whose weight was measured in advance.

2) The SUS mesh was immersed in 100mL of ethyl acetate for 24 hours.

3) The SUS net was taken out and dried at 75℃for 4.5 hours.

4) The mass (W2) after drying was determined, and the gel fraction of the adhesive composition was measured according to the following formula.

Gel fraction (%) =100× (W2-W0)/W1

[ adhesion ]

For the release film-attached adhesive sheets produced in examples and comparative examples, one release film was peeled off, and a polyethylene terephthalate film (trade name "cosmosin A4300", thickness 100 μm) as a backing film was roll-pressed with a hand roll. The sheet was cut into strips 10mm wide by 100mm long, and the remaining release film was peeled off to expose the adhesive surface, which was then attached to soda lime glass with a hand roll. Autoclave treatment (60 ℃ C., gauge pressure 0.2MPa, 20 minutes) was performed, and the adhesive force measurement sample was prepared by performing finish adhesion.

The adhesive sheet was peeled from the glass by stretching the liner film at an angle of 180℃at a peeling speed of 60 mm/min using a universal material tester (model "5965" manufactured by INSTRON Co., ltd.), and the tensile strength was measured by a load cell, and the 180℃peeling strength (N/cm) of the adhesive sheet to the glass was measured and shown as "adhesive force" in Table 1.

[ protective function of coated polarizing element ]

For the release film-attached adhesive sheets produced in examples and comparative examples, one release film was peeled off, the adhesive sheet was roll-pressed against the cover layer of the coated polarizing element with a hand roll, and the adhesive surface exposed by peeling off the remaining release film was attached to soda lime glass with a hand roll. Autoclave treatment (60 ℃ C., gauge pressure 0.2MPa, 20 minutes) was performed, and the protective function measurement sample of the coated polarizing element was prepared by performing finish adhesion.

For the foregoing samples, a xenon light resistance tester (Atlas co., ltd, apparatus name "Ci 4000") was used to measure the illuminance: 0.55W/cm ² The light resistance test was conducted under ultraviolet irradiation conditions of (340 nm) for 40 hours.

As a result of the light resistance test, the values of the changes in the polarization degree at the wavelength 595nm before and after the light resistance test (polarization degree before the test-polarization degree after the test) are shown in table 1.

The degree of polarization (Pe) was calculated as follows: the measurement light of the linear polarized light was made incident on the anisotropic dye film, and the "transmittance of the anisotropic dye film for polarized light in the light absorption axis direction" and the "transmittance of the anisotropic dye film for polarized light in the polarization axis direction" were measured by a spectrophotometer (manufactured by Otsuka electronics Co., ltd., product name "RETS-100") having a Glan-Thompson polarizer, and calculated according to the following formulas.

Pe＝(Ty-Tz)/(Ty+Tz)

(in the formula (I),

tz is the transmittance of the anisotropic pigment film for polarized light in the light absorption axis direction;

ty is the transmittance of the anisotropic dye film for polarized light in the direction of the polarization axis. )

Evaluation was performed on the following basis.

O (good): the amount of change in the polarization degree before and after the light resistance test is 0.25 or less.

X (horn): the amount of change in the polarization degree before and after the light resistance test is larger than 0.25.

The results obtained by the measurement and evaluation are shown in table 1.

TABLE 1

As is clear from the results of the experiments performed in the above examples and the present inventors, in order to prevent the polarization performance of the coated polarizing element from decreasing with time due to exposure, at least the transmittance at a wavelength of 400nm lower than that in comparative example 1 is required.

As is clear from the results of the experiments conducted by the present inventors in the examples described above and heretofore, regarding an adhesive composition comprising a (meth) acrylic polymer (a) and an ultraviolet absorber (B), if the transmittance at a wavelength of 400nm of an adhesive layer formed from the adhesive composition is 50% or less, it is possible to prevent the deterioration of polarization performance of a coated polarizer with time due to exposure by using the adhesive composition in combination with the coated polarizer.

Example II-1

200 parts by mass of a (meth) acrylic polymer (A-1) solution (dilution solvent: ethyl acetate solid content: 50% by mass), 6 parts by mass of a hydroxyl group-containing benzophenone compound (B1-1), 3 parts by mass of a photo-cleavage type radical polymerization initiator (C-1), 25 parts by mass of a multifunctional (meth) acrylate initiator (D-1), 0.3 part by mass of 3-glycidoxypropyl methyl diethoxysilane (Xinyue silicone system, KBM 403) as a silane coupling agent, 0.3 part by mass of 1,2, 3-triazole as an anticorrosive agent, and 101 parts by mass of ethyl acetate were uniformly mixed to prepare an adhesive composition II-1.

On a release film (DIAFOIL MRV, manufactured by Mitsubishi chemical corporation) having a thickness of 100 μm subjected to the silicone release treatment, the adhesive composition II-1 was spread into a sheet so that the thickness of the adhesive composition II-1 after the solvent drying became 50. Mu.m.

Then, the sheet-like adhesive composition II-1 was put into a dryer heated to 95℃together with a release film, and kept for 10 minutes, to volatilize the solvent contained in the adhesive composition 1.

Further, a release film (DIAFOIL MRQ, manufactured by Mitsubishi chemical corporation) having a thickness of 75 μm was laminated on the sheet-like adhesive composition II-1, which had been subjected to the silicone release treatment, to form a laminate, and the adhesive composition II-1 was subjected to a high-pressure mercury lamp to give a cumulative irradiation amount of 1000mJ/cm at a wavelength of 365nm through the release film ² The cumulative irradiation amount at a wavelength of 405nm was 1400mJ/cm ² The light irradiation was performed in this manner to obtain a release film-attached pressure-sensitive adhesive sheet II-1 (pressure-sensitive adhesive sheet thickness: 50 μm) having release films laminated on both front and back sides.

Examples II-2 to II-3, reference example II-1, and comparative examples II-1 to II-2

Adhesive compositions II-2 to II-6 and release film-equipped adhesive sheets II-2 to II-6 were produced in the same manner as in example II-1 except that the types and the amounts of the (meth) acrylic polymer (A), the ultraviolet absorber (B), the radical polymerization initiator (C), the polyfunctional (meth) acrylate (D) and other additives used were as shown in Table 2.

< evaluation >

The adhesive compositions II-1 to II-6 and the adhesive sheets II-1 to II-6 obtained in the examples, the reference examples and the comparative examples were measured and evaluated as follows.

[ light transmittance ]

The release films on both sides of the release film-equipped adhesive sheets produced in examples, reference examples and comparative examples were peeled off in order, the adhesive sheets (thickness: 50 μm) were attached so as to be sandwiched between 2 sheets of soda lime glass (thickness: 0.5 mm), autoclave treatment (60 ℃ C., gauge pressure: 0.2MPa, 20 minutes) was performed, and finish attachment was performed to produce samples for evaluation of optical characteristics.

The transmittance of the prepared sample for evaluating optical characteristics was measured in the wavelength region of 360 to 430nm by a spectrophotometer (manufactured by Shimadzu corporation; apparatus name "UV 2450").

[ b value ]

The b-value of the prepared sample for evaluating optical characteristics was measured by a spectrocolorimeter (Suga Test Instruments co., ltd., manufactured by ltd., apparatus name "SC-P") according to JIS Z8781-4.

[ gel fraction ]

The gel fractions of the adhesive compositions prepared halfway in examples, reference examples and comparative examples were measured according to the following procedure.

1) The adhesive composition (W1) was weighed and coated on SUS mesh (W0) whose weight was measured in advance.

2) The SUS mesh was immersed in 100mL of ethyl acetate for 24 hours.

3) The SUS net was taken out and dried at 75℃for 4.5 hours.

4) The mass (W2) after drying was determined, and the gel fraction of the adhesive composition was measured according to the following formula.

Gel fraction (%) =100× (W2-W0)/W1

[ adhesion ]

For the release film-attached adhesive sheets produced in examples, reference examples and comparative examples, one release film was peeled off, and a polyethylene terephthalate film (trade name "cosmosin A4300", thickness 100 μm) as a backing film was roll-pressed with a hand roll. The sheet was cut into strips 10mm wide by 100mm long, and the remaining release film was peeled off to expose the adhesive surface, which was then attached to soda lime glass with a hand roll. Autoclave treatment (60 ℃ C., gauge pressure 0.2MPa, 20 minutes) was performed, and the adhesive force measurement sample was prepared by performing finish adhesion.

The adhesive sheet was peeled from the glass by stretching the liner film at an angle of 180℃at a peeling speed of 60 mm/min using a universal material tester (model "5965" manufactured by INSTRON Co., ltd.), and the tensile strength was measured by a load cell, and the 180℃peeling strength (N/cm) of the adhesive sheet to the glass was measured and shown as "adhesive force" in Table 2.

[ durability ]

The above-mentioned sample for optical evaluation was subjected to illumination intensity with a xenon light resistance tester (Atlas co., ltd, equipment name "Santest xps+"): 60W/cm ² (300-400 nm), black panel temperature: the test was performed under ultraviolet irradiation at 63℃for 100 hours, and the b-value of the sample after the test was measured by a spectrocolorimeter (Suga Test Instruments Co., ltd., apparatus name "SC-P") in accordance with JIS Z8781-4.

Evaluation was performed on the following basis.

O (good): the change in b-value before and after the durability test is 3 or less.

X (horn): the change in b-value before and after the durability test is greater than 3.

[ protection function of constituent Member of image display device ]

The adhesive sheets with release films produced in examples, reference examples and comparative examples were peeled off one release film, the adhesive sheet was rolled onto the cover layer of the coated polarizing element with a hand roll, and the adhesive surface exposed by peeling off the remaining release film was attached to soda lime glass with a hand roll. Autoclave treatment (60 ℃ C., gauge pressure 0.2MPa, 20 minutes) was performed, and the protective function measurement sample of the coated polarizing element was prepared by performing finish adhesion.

For the foregoing samples, a xenon light resistance tester (Atlas co., ltd, apparatus name "Ci 4000") was used to measure the illuminance: 0.55W/cm ² Light resistance under ultraviolet irradiation at 340nm for 40 hoursAnd (5) sex test.

As a result of the light resistance test, the values of the changes in the polarization degree at the wavelength 595nm before and after the light resistance test (polarization degree before the test-polarization degree after the test) are shown in table 2.

The degree of polarization (Pe) was calculated as follows: the measurement light of the linear polarized light was made incident on the anisotropic dye film, and the "transmittance of the anisotropic dye film for polarized light in the light absorption axis direction" and the "transmittance of the anisotropic dye film for polarized light in the polarization axis direction" were measured by a spectrophotometer (manufactured by Otsuka electronics Co., ltd., product name "RETS-100") having a Glan-Thompson polarizer, and calculated according to the following formulas.

Pe＝(Ty-Tz)/(Ty+Tz)

(in the formula (I),

tz is the transmittance of the anisotropic pigment film for polarized light in the light absorption axis direction;

ty is the transmittance of the anisotropic dye film for polarized light in the direction of the polarization axis. )

Evaluation was performed on the following basis.

O (good): the amount of change in the polarization degree before and after the light resistance test is 0.25 or less

X (horn): the amount of change in the polarization degree before and after the light resistance test is greater than a value of 0.25

[ comprehensive evaluation ]

The determination of "good" in the evaluation of the protection function of the image display device constituent member and the determination of "x (pore)" in the evaluation of the protection function of the image display device constituent member are both determined as "good", and the determination of "x (pore)" in either or both of the evaluation of the protection function of the image display device constituent member and the durability test is determined as "x (pore)".

The results obtained by the measurement and evaluation are shown in table 2.

TABLE 2

As is clear from the results of the experiments conducted by the present inventors in the examples and heretofore, it is necessary to make the transmittance at a wavelength of 400nm in reference example II-1 lower than 30% at least in order to obtain excellent light-proof reliability.

Description of the reference numerals

1. Adhesive sheet for coated polarizing element or adhesive sheet for image display device constituent member of the present invention

2. Cover glass or plastic sheet

3. Coated polarizing element (polarizing layer) or optically anisotropic layer (polarizing layer)

4. Orientation film

5. Coated polarizing element (retardation layer) or optically anisotropic layer (retardation layer)

6. Polarizing plate

7. Phase difference plate

8. Liquid crystal panel

9. Organic EL panel

10. Resin sheet or glass

11a, 11b release film

12a to 12c adhesive or pressure-sensitive adhesive layer

Claims (40)

1. An adhesive composition for a coated polarizing element, which comprises a (meth) acrylic polymer (A), an ultraviolet absorber (B) and a radical polymerization initiator (C), wherein the adhesive layer formed from the adhesive composition has a transmittance at a wavelength of 400nm of 50% or less.

2. The adhesive composition for a coated polarizing element according to claim 1, further comprising a multifunctional (meth) acrylate (D).

3. The adhesive composition for a coated polarizing element according to claim 1 or 2, wherein the content of the ultraviolet absorber (B) is 0.1 part by mass or more with respect to 100 parts by mass of the (meth) acrylic polymer (a).

4. The adhesive composition for a coated polarizing element according to any one of claims 1 to 3, wherein the ultraviolet absorber (B) comprises a benzophenone structure.

5. The adhesive composition for coated polarizing elements according to any one of claims 1 to 4, wherein the multifunctional (meth) acrylate (D) is a (meth) acrylate oligomer having a molecular weight of 3000 or more.

6. The adhesive composition for a coated polarizing element according to any one of claims 1 to 5, wherein the (meth) acrylic polymer (a) has a polymerizable carbon double bond group in a side chain.

7. The adhesive composition for a coated polarizing element according to any one of claims 1 to 6, wherein the radical polymerization initiator (C) is a photocleavable radical polymerization initiator.

8. The adhesive composition for a coated polarizing element according to any one of claims 1 to 7, which is curable in multiple stages.

9. An adhesive sheet for a coated polarizing element, comprising an adhesive material layer formed using the adhesive composition for a coated polarizing element according to any one of claims 1 to 8.

10. The adhesive sheet for coated polarizing element according to claim 9, wherein b is 10 or less.

11. The adhesive sheet for a coated polarizing element according to claim 9 or 10, which has a gel fraction of 20% or more and 95% or less.

12. The adhesive sheet for a coated polarizing element according to any one of claims 9 to 11, which has a thickness of 10 μm or more and 175 μm or less.

13. An adhesive sheet with a release film, comprising the adhesive sheet for a coated polarizing element according to any one of claims 9 to 12 and a release film laminated together.

14. A laminated sheet comprising a resin sheet or a film glass comprising, as a main component resin, one or more resins selected from the group consisting of cycloolefin resins, cellulose triacetate resins, polymethyl methacrylate resins, epoxy resins, polyester resins and polyimide resins, on at least one side of the adhesive sheet for a coated polarizing element according to any one of claims 9 to 12.

15. A coated polarizing element with an adhesive layer, comprising an adhesive layer formed from the adhesive composition for a coated polarizing element according to any one of claims 1 to 8 on at least one side of the coated polarizing element.

16. An adhesive sheet with a polarizing element, comprising a coated polarizing element on at least one side of the adhesive sheet according to any one of claims 9 to 12.

17. An image display device having a structure in which a coated polarizing element and an adhesive layer are laminated directly or via other members,

the adhesive layer is formed from an adhesive composition containing a (meth) acrylic polymer (A), an ultraviolet absorber (B), and a radical polymerization initiator (C), and has a transmittance at a wavelength of 400nm of 50% or less.

18. The image display device of claim 17, wherein the adhesive layer has a transmittance of less than 20% at a wavelength of 380 nm.

19. The image display device according to claim 17 or 18, wherein the adhesive layer has a transmittance of 50% or more at a wavelength of 430 nm.

20. The image display device according to any one of claims 17 to 19, wherein the transmittance T (380) at a wavelength of 380nm, the transmittance T (430) at a wavelength of 430nm, and the b value of the adhesive layer satisfy the following formulas (I) and (II),

0≤T(380)×b*≤50(I)

70≤T(430)×b*≤220(II)。

21. An adhesive sheet for image display device constituent members, which is formed from an adhesive composition comprising a (meth) acrylic copolymer (A), a hydroxyl group-containing benzophenone compound (B1) and a radical polymerization initiator (C), and has a light transmittance at a wavelength of 400nm of less than 30%.

22. The adhesive sheet for image display device constitution member according to claim 21, having a transmittance at 380nm of less than 20%.

23. The adhesive sheet for image display device constituent members according to claim 21 or 22, which has a transmittance at a wavelength of 430nm of 50% or more.

24. The adhesive sheet for image display device constituent members according to any one of claims 21 to 23, wherein the transmittance T (380) at a wavelength of 380nm, the transmittance T (430) at a wavelength of 430nm and the values of b satisfy the following formulas (I) and (II),

0≤T(380)×b*≤50(I)

70≤T(430)×b*≤220(II)。

25. the pressure-sensitive adhesive sheet for image display device constituent members according to any one of claims 21 to 24, wherein the content of the hydroxyl group-containing benzophenone compound (B1) is 0.1 parts by mass or more relative to 100 parts by mass of the (meth) acrylic polymer (a).

26. The adhesive sheet for image display device constituent members according to any one of claims 21 to 25, further comprising a polyfunctional (meth) acrylate (D).

27. The adhesive sheet for image display device constitutional members according to any one of claims 21 to 26, wherein the (meth) acrylic polymer (a) has a photoactive site in a side chain.

28. The pressure-sensitive adhesive sheet for image display device constituent members according to claim 26, wherein the polyfunctional (meth) acrylate (D) is a (meth) acrylate oligomer having a molecular weight of 3000 or more.

29. The adhesive sheet for image display device constituent members according to any one of claims 21 to 28, wherein the radical polymerization initiator (C) is a photopolymerization initiator having a great absorption at least at a wavelength of 400 to 430 nm.

30. The pressure-sensitive adhesive sheet for image display device constituent members according to any one of claims 21 to 29, wherein a content mass ratio of the hydroxyl group-containing benzophenone compound (B1) to the radical polymerization initiator (C) is (B1): (C) =1: 0.05 to 1:20.

31. the pressure-sensitive adhesive sheet for image display device constituent members according to any one of claims 21 to 30, having a gel fraction of 20% or more and 95% or less.

32. The pressure-sensitive adhesive sheet for image display device constituent members according to any one of claims 21 to 31, wherein the value of b is 3.0 or less.

33. The pressure-sensitive adhesive sheet for image display device constituent members according to any one of claims 21 to 32, having a thickness of 10 μm or more and 175 μm or less.

34. The adhesive sheet for image display device constituent members according to any one of claims 21 to 33, wherein the image display device constituent members are obtained by integrating a reflective sheet, a light guide plate with a light source, a diffusion film, a prism sheet, a liquid crystal panel, a phase difference plate, a glass substrate, a polarizing plate, an organic EL panel, an electrode, an antireflection film, a color filter, a touch sensor, a glass cover sheet, a plastic cover sheet, or two or more members thereof.

35. The adhesive sheet for image display device constituent members according to any one of claims 21 to 34, which is curable in multiple stages.

36. The pressure-sensitive adhesive sheet for image display device constituent members according to any one of claims 21 to 35, which has a multilayer structure of 2 or more layers.

37. An adhesive sheet with a release film, comprising the adhesive sheet for an image display device constituent member according to any one of claims 21 to 36 and a release film laminated.

38. An adhesive sheet with an image display device constituent member, comprising the adhesive sheet for an image display device constituent member according to any one of claims 21 to 36 on an image display device constituent member.

39. A laminate sheet comprising a resin sheet or a film glass having as a main component resin one or more resins selected from the group consisting of cycloolefin resins, cellulose triacetate resins, polymethyl methacrylate resins, epoxy resins, polyester resins, and polyimide resins, on at least one side of the pressure-sensitive adhesive sheet for an image display device constituent member of any one of claims 21 to 36.

40. An image display device comprising the pressure-sensitive adhesive sheet for image display device constituent members according to any one of claims 21 to 36.