Adhesives and adhesive layers

Abstract

To provide an adhesive sheet carrying an adhesive layer in which yellow discoloration hardly occurs even when the adhesive layer is stuck on a substrate having a metallic electrode portion and which exhibits a function to shield ultraviolet light of a wide range from a short wavelength region of around 200 nm to a long wavelength region around 400 nm, and to provide an adhesive sheet from which an ultraviolet absorber hardly precipitates even after a lapse of time.SOLUTION: Provided is an adhesive comprising: a dye (A) that has at least one triazine ring and has one, two, or three naphthalene rings bound directly to one triazine ring; a dye (B) that has at least one triazine ring and has one, two, or three aromatic rings bound directly to one triazine ring, where one of the aromatic rings has a hydroxy group on a carbon neighboring the position of bonding to the triazine ring while other one or two of the aromatic rings do not have hydroxy groups on carbons neighboring the positions of bonding to the triazine ring; an acrylic polymer (C); and a curing agent (D) (where the dye (B) is other than the dye (A)).SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a pressure-sensitive adhesive, and more particularly to a pressure-sensitive adhesive that is suitable for use in forming a pressure-sensitive adhesive layer in a pressure-sensitive adhesive sheet that has excellent ultraviolet shielding performance and is used in a variety of products, including electronic devices and displays. [Background technology]

[0002] BACKGROUND ART Pressure-sensitive adhesive sheets having a pressure-sensitive adhesive layer formed from a pressure-sensitive adhesive are easy to handle and are therefore used in a variety of products in a wide range of fields, including electronic devices and displays. Among these, acrylic adhesives are widely used due to their excellent weather resistance, durability, heat resistance, transparency, etc. The highly transparent adhesive sheets used in the formation of display devices, which have become thinner and lighter in recent years, are generally called OCA (Optical Clear Adhesive).

[0003] Because the OCA used in displays has a direct impact on display performance, it is required to have high transparency, as well as resistance to peeling and degradation by ultraviolet rays. For example, Patent Document 1 discloses the use of a pressure-sensitive acrylate adhesive containing a benzotriazole derivative as an optical pressure-sensitive adhesive tape that does not affect the electrical conductivity of the indium tin oxide film (ITO film) used in capacitive touch panels and minimizes yellowing of the ITO film. Furthermore, Patent Document 2 describes an adhesive composition for decorating window glass, which contains an acrylic polymer using a specific amount of a monomer having an amide group, a compound having a triazine structure, and a compound having a benzotriazole structure, and describes that the adhesive composition undergoes little change in appearance and has excellent reworkability. Furthermore, Patent Document 3 discloses triazine compounds with various skeletons. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Special Publication No. 2016-537479 [Patent Document 2] Japanese Patent Application Publication No. 2018-058915 [Patent Document 3] Japanese Patent Application Laid-Open No. 2013-075841 Summary of the Invention [Problem to be solved by the invention]

[0005] The pressure-sensitive acrylate adhesive containing a benzotriazole derivative described in Patent Document 1 can absorb ultraviolet light with a maximum wavelength of about 360 nm, making it extremely difficult to efficiently absorb UVA with a long wavelength of about 400 nm. The benzotriazole-based compounds and triazine-based compounds described in Patent Document 2 bond with metal ions such as copper ions, causing the adhesive layer to yellow, which is a problem in that OCAs containing these UV absorbers cannot be used to bond substrates having metal electrode sites. Furthermore, the triazine-based compound disclosed in Patent Document 3 contains many aromatic rings and has a rigid skeletal structure, so it has extremely low solubility in organic solvents and resins contained in adhesives, and the amount that can be uniformly supported in a dissolved state in the adhesive layer after coating and drying is very small, so it is unable to exhibit sufficient UV absorption ability. Furthermore, there is a concern that the UV absorber that was uniformly supported in the adhesive layer may crystallize and precipitate in the adhesive layer over time, which poses a problem of inconvenient handling.

[0006] The present invention aims to solve the above-mentioned problems, and specifically aims to provide an adhesive sheet that is resistant to yellowing even when attached to a substrate having a metal electrode portion, and that carries an adhesive layer that exhibits a wide range of ultraviolet blocking function from the short wavelength region around 200 nm to the long wavelength region around 400 nm. In addition to the above, a further object of the present invention is to provide a pressure-sensitive adhesive sheet that is excellent in stability over time, in which the ultraviolet absorber is unlikely to precipitate even over time. [Means for solving the problem]

[0007] As a result of extensive research, the present inventors have found that the above problems can be solved by an adhesive and an adhesive layer containing two specific types of dyes having a triazine ring, as shown below, and have completed the present inventions [1] to

[10] below.

[0008] [1] A dye (A) which is a triazine compound having at least one triazine ring and one, two or three naphthalene rings directly bonded to one triazine ring; a dye (B) which is a triazine compound having at least one triazine ring and one, two or three aromatic rings directly bonded to one triazine ring, wherein one of the aromatic rings has a hydroxyl group on a carbon atom adjacent to the bonding position to the triazine ring, and the other one or two of the aromatic rings do not have a hydroxyl group on a carbon atom adjacent to the bonding position to the triazine ring; an acrylic polymer (C); a curing agent (D), Contains adhesive. (However, the dye (B) is other than the dye (A).)

[0009] [2] The pressure-sensitive adhesive according to [1], wherein the dye (A) comprises a compound selected from the group consisting of the following general formulas (1), (2), and (3):

[0010] [ka]

[0011] (In general formulas (1) to (3), R 1b ~R 1g , R 2a ~R 2g , R 3a ~R 3gare each independently a hydrogen atom, a hydroxyl group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a nitrile group, a nitro group, a sulfo group, R7, Ar1, or a group represented by the following general formulas (4-1) to (4-3). R7 is an alkyl group having 1 to 20 carbon atoms which may have a substituent, an alkenyl group having 2 to 20 carbon atoms which may have a substituent, an alkoxy group having 1 to 20 carbon atoms which may have a substituent, or an alkenyloxy group having 2 to 20 carbon atoms which may have a substituent, a functional group in which carbon atoms of an optionally substituted alkyl group having 1 to 20 carbon atoms are linked together by one or more of -O-, -CO-, -COO-, -OCO-, -CONH-, or -NHCO-, wherein carbon atoms of an optionally substituted alkenyl group having 2 to 20 carbon atoms are linked together, carbon atoms of an optionally substituted alkoxy group having 1 to 20 carbon atoms are linked together, and carbon atoms of an optionally substituted alkenyloxy group having 2 to 20 carbon atoms are linked together by one or more of -O-, -CO-, -COO-, -OCO-, -CONH-, or -NHCO-, The substituent is selected from the group consisting of a hydroxyl group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a nitrile group, a nitro group, a carboxyl group, and a sulfo group. Ar1 is an aryl group having 6 to 20 carbon atoms which may have a substituent, or an aryloxy group having 6 to 20 carbon atoms which may have a substituent, and the substituent is a hydroxyl group, an alkyl group having 1 to 20 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, an alkenyloxy group having 2 to 20 carbon atoms, an aryloxy group having 6 to 20 carbon atoms, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a nitrile group, a nitro group, It is selected from the group consisting of a carboxyl group and a sulfo group. In addition, in the general formulae (2) and (3), R4, R5, and R6 are a hydroxyl group, R7, or Ar1.

[0012] [ka]

[0013] In general formula (4-1), X1 is -CO-, -COO-, -OCO-, -CONH-, or -NHCO-. R8 is a hydrogen atom, a hydroxyl group, R7, or Ar1. However, * in general formula (4-1) represents the bonding site with the naphthalene ring of general formulas (1) to (3).

[0014] [ka]

[0015] [ka]

[0016] In general formula (4-3), X4 and X5 each independently represent -CO-, -COO-, -OCO-, -CONH-, or -NHCO-. 11 R is a linear or branched alkylene group having 1 to 20 carbon atoms or an arylene group having 6 to 20 carbon atoms. 12 is R7 or Ar1, and n is 1 to 20. However, * in general formula (4-3) represents the bonding site with the naphthalene ring of general formulas (1) to (3).

[0017] [3] The dye (A) is In the case of general formula (1), R 2a and R 3a is not a hydroxyl group, In the case of general formula (2), R 2a is not a hydroxyl group, and when R4 is R7 or Ar1, and Ar1 is an aryl group having 6 to 20 carbon atoms which may have a substituent, or an aryloxy group having 6 to 20 carbon atoms which may have a substituent, the carbon atom adjacent to the bonding position to the triazine ring does not have a hydroxyl group, In the case of general formula (3), R5 and R6 are each independently R7 or Ar1, and when Ar1 is an aryl group having 6 to 20 carbon atoms which may have a substituent, or an aryloxy group having 6 to 20 carbon atoms which may have a substituent, the carbon atom adjacent to the bonding position to the triazine ring does not have a hydroxyl group. [2] The adhesive of.

[0018] [4] The pressure-sensitive adhesive according to any one of [1] to [3], wherein the dye (B) is a compound represented by the following general formula (12):

[0019] [ka]

[0020] In general formula (12), R1 is an alkyl group having 1 to 20 carbon atoms which may have a substituent; an alkenyl group having a prime number of 2 to 20; a functional group in which carbon atoms of an optionally substituted alkyl group having 1 to 20 carbon atoms are linked together by one or more of -O-, -CO-, -COO-, -OCO-, -CONH-, or -NHCO-, wherein carbon atoms of an optionally substituted alkenyl group having 2 to 20 carbon atoms are linked together, carbon atoms of an optionally substituted alkoxy group having 1 to 20 carbon atoms are linked together, and carbon atoms of an optionally substituted alkenyloxy group having 2 to 20 carbon atoms are linked together by one or more of -O-, -CO-, -COO-, -OCO-, -CONH-, or -NHCO-, The substituent is 、 selected from the group consisting of a hydroxyl group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a nitrile group, a nitro group, a carboxyl group, and a sulfo group; Ar1 and Ar2 are each independently an aryl group having 6 to 20 carbon atoms which may have a substituent. or an aryloxy group having 6 to 20 carbon atoms which may have a substituent, and the substituent is 、 It is selected from the group consisting of a hydroxyl group, an alkyl group having 1 to 20 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, an alkenyloxy group having 2 to 20 carbon atoms, an aryloxy group having 6 to 20 carbon atoms, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a nitrile group, a nitro group, a carboxyl group, and a sulfo group.

[0021] [5] The pressure-sensitive adhesive according to any one of [1] to [4], wherein the acrylic polymer (C) is a copolymer of an amide acrylic monomer and another monomer.

[0022] [6] The pressure-sensitive adhesive according to any one of [1] to [5], wherein the acrylic polymer (C) is a polymer having a hydroxyl group.

[0023] [7] The pressure-sensitive adhesive according to [5] or [6], wherein the amide-based acrylic monomer is diacetone acrylamide and / or N-vinylpyrrolidone.

[0024] [8] The pressure-sensitive adhesive according to any one of [1] to [7], wherein the curing agent (D) is an isocyanate-based curing agent.

[0025] [9] An adhesive layer which is a cured product of the adhesive according to any one of [1] to [8].

[0026]

[10] The optical transmittance of the optical fiber according to [9] is 5% or less over the entire range of 200 to 400 nm. Adhesive layer on the back. [Effects of the Invention]

[0027] The present invention makes it possible to provide a pressure-sensitive adhesive sheet that is resistant to yellowing even when attached to a substrate having a metal electrode portion and has a wide range of ultraviolet blocking properties from the short wavelength region around 200 nm to the long wavelength region around 400 nm.In addition to the above, the present invention also makes it possible to provide a pressure-sensitive adhesive sheet in which the ultraviolet absorber is resistant to precipitation over time by compatibilizing the ultraviolet absorber and the acrylic polymer in the pressure-sensitive adhesive layer. DETAILED DESCRIPTION OF THE INVENTION

[0028] The present invention will be described in detail below. Note that the embodiment described below is an example of the present invention. The present invention is not limited to the following embodiment, and includes modifications that are implemented within the scope of the present invention.

[0029] As described above, the present invention contains two specific dyes (A) and (B) having a triazine ring. [Dye (A)] The dye (A) is a triazine compound having at least one triazine ring and one, two, or three naphthalene rings directly bonded to one triazine ring. The dye (A) has excellent absorption properties for ultraviolet light in the long wavelength region around 400 nm and visible light in the short wavelength region of 400 to 420 nm. The dye (A) is also called an ultraviolet absorber (A). The dye (A) preferably used in the present invention includes compounds selected from the group consisting of the following general formulae (1), (2) and (3).

[0030] [ka]

[0031] (In general formulas (1) to (3), R 1b ~R 1g , R 2a ~R 2g , R 3a ~R 3g are each independently a hydrogen atom, a hydroxyl group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a nitrile group, a nitro group, a sulfo group, R7, Ar1, or a group represented by the following general formulas (4-1) to (4-3). R7 is an alkyl group having 1 to 20 carbon atoms which may have a substituent, an alkenyl group having 2 to 20 carbon atoms which may have a substituent, an alkoxy group having 1 to 20 carbon atoms which may have a substituent, or an alkenyloxy group having 2 to 20 carbon atoms which may have a substituent, a functional group in which carbon atoms of an optionally substituted alkyl group having 1 to 20 carbon atoms are linked together by one or more of -O-, -CO-, -COO-, -OCO-, -CONH-, or -NHCO-, wherein carbon atoms of an optionally substituted alkenyl group having 2 to 20 carbon atoms are linked together, carbon atoms of an optionally substituted alkoxy group having 1 to 20 carbon atoms are linked together, and carbon atoms of an optionally substituted alkenyloxy group having 2 to 20 carbon atoms are linked together by one or more of -O-, -CO-, -COO-, -OCO-, -CONH-, or -NHCO-, The substituent is selected from the group consisting of a hydroxyl group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a nitrile group, a nitro group, a carboxyl group, and a sulfo group. Ar1 is an aryl group having 6 to 20 carbon atoms which may have a substituent, or an aryloxy group having 6 to 20 carbon atoms which may have a substituent, and the substituent is a hydroxyl group, an alkyl group having 1 to 20 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, an alkenyloxy group having 2 to 20 carbon atoms, an aryloxy group having 6 to 20 carbon atoms, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a nitrile group, a nitro group, It is selected from the group consisting of a carboxyl group and a sulfo group. In addition, in the general formulae (2) and (3), R4, R5, and R6 are a hydroxyl group, R7, or Ar1.

[0032] [ka]

[0033] In general formula (4-1), X1 is -CO-, -COO-, -OCO-, -CONH-, or -NHCO-. R8 is a hydrogen atom, a hydroxyl group, R7, or Ar1. However, * in general formula (4-1) represents the bonding site with the naphthalene ring of general formulas (1) to (3).

[0034] [ka]

[0035] In the general formula (4-2), X2 and X3 are each independently -CO-, -COO-, -OCO-, -CONH-, or -NHCO-. R9 is an arylene group having 6 to 20 carbon atoms. R 10 is R7 or Ar1, where * in general formula (4-2) represents the bonding site with the naphthalene ring of general formulas (1) to (3).

[0036] [ka]

[0037] In general formula (4-3), X4 and X5 each independently represent -CO-, -COO-, -OCO-, -CONH-, or -NHCO-. 11 R is a linear or branched alkylene group having 1 to 20 carbon atoms or an arylene group having 6 to 20 carbon atoms. 12 is R7 or Ar1, and n is 1 to 20. However, * in general formula (4-3) represents the bonding site with the naphthalene ring of general formulas (1) to (3).

[0038] The general formula (4-1) is preferably a group containing the general formula (4).

[0039] [ka]

[0040] In the general formula (4), Y is -NH- or -O-. 13 is a hydrogen atom, a hydroxyl group, an alkyl group having 1 to 20 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, an alkenyloxy group having 2 to 20 carbon atoms, an aryloxy group having 6 to 20 carbon atoms, an alkyl group having 1 to 20 carbon atoms or an aryl group having 6 to 20 carbon atoms which may have a substituent such as a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a nitrile group, a nitro group, a carboxyl group or a sulfo group. However, the * mark in general formula (4) indicates the bonding site with the naphthalene ring in general formulas (1) to (3).

[0041] Examples of the compound represented by general formula (1) include the following compounds. [ka]

[0042] [ka]

[0043] [ka]

[0044] [ka]

[0045] Examples of the compound represented by general formula (2) include the following compounds. [ka]

[0046] Examples of the compound represented by general formula (3) include the following compounds. [ka]

[0047] In terms of solubility in organic solvents and acrylic polymers, the dye (A) preferably has one naphthalene ring bonded to one triazine ring. In addition, the dye (A) may be: In the case of general formula (1), R 2a and R 3a is not a hydroxyl group, In the case of general formula (2), R 2a is not a hydroxyl group, and when R4 is R7 or Ar1, and Ar1 is an aryl group having 6 to 20 carbon atoms which may have a substituent, or an aryloxy group having 6 to 20 carbon atoms which may have a substituent, the position adjacent to the bonding position to the triazine ring is The carbon atom at the position does not have a hydroxyl group, In the case of general formula (3), R5 and R6 are each independently R7 or Ar1, and when Ar1 is an aryl group having 6 to 20 carbon atoms which may have a substituent, or an aryloxy group having 6 to 20 carbon atoms which may have a substituent, a triazine compound in which the carbon atom adjacent to the bonding position to the triazine ring does not have a hydroxyl group is preferred from the viewpoint of low reactivity with metals and of preventing yellowing of the adhesive layer even when the adhesive sheet is attached to a substrate having a metal electrode site. Examples of such dyes (A) include (A-4), (A-20), (A-22) to (A-25), and (A-28) to (A-33), with (A-28) being particularly preferred from the viewpoint of the ultraviolet wavelengths absorbed. Although the detailed reason is unknown, compared to triazine compounds in which multiple benzene rings, rather than a naphthalene ring, are directly bonded to a triazine ring and each benzene ring has a hydroxyl group at the ortho-position, compounds such as (A-14) and (A-26) in which multiple naphthalene rings directly bonded to the triazine ring each have a hydroxyl group at the 2-position are less reactive with metals, and the adhesive layer is less likely to yellow even when the adhesive sheet is attached to a substrate with a metal electrode site.

[0048] The triazine compounds can be synthesized using known methods for synthesizing compounds having a triazine structure. For example, a method of adding naphthol or a naphthol derivative to cyanuric chloride using aluminum trichloride can be used. Another method is a cyclocondensation reaction of methyl 2-hydroxy-1-naphthoate with benzamidine hydrochloride using sodium methoxide. The naphthalene ring connected to the triazine ring via a single bond and the substituents on R4, R5, and R6 can be introduced after or before the triazine structure is formed.

[0049] [Dye (B)] Dye (B) is a triazine compound having at least one triazine ring and one, two, or three aromatic rings directly bonded to one triazine ring, in which one of the aromatic rings has a hydroxyl group on the carbon adjacent to the bonding position to the triazine ring, and the other one or two aromatic rings do not have a hydroxyl group on the carbon adjacent to the bonding position to the triazine ring, provided that the dye (B) is other than the dye (A).

[0050] An example of the dye (B) preferably used in the present invention is a compound represented by the following general formula (12). [ka]

[0051] In general formula (12), R1 is an alkyl group having 1 to 20 carbon atoms which may have a substituent; an alkenyl group having a prime number of 2 to 20; Between the carbon atoms of an alkyl group having 1 to 20 carbon atoms which may have a substituent, between the carbon atoms of an alkenyl group having 2 to 20 carbon atoms which may have a substituent, between the carbon atoms of an alkoxy group having 1 to 20 carbon atoms which may have a substituent, a functional group in which carbon atoms of an alkenyloxy group having 2 to 20 carbon atoms may be linked by one or more of -O-, -CO-, -COO-, -OCO-, -CONH-, or -NHCO-; The substituent is 、 selected from the group consisting of a hydroxyl group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a nitrile group, a nitro group, a carboxyl group, and a sulfo group; Ar1 and Ar2 are each independently an aryl group having 6 to 20 carbon atoms which may have a substituent. or an aryloxy group having 6 to 20 carbon atoms which may have a substituent, and the substituent is、 It is selected from the group consisting of a hydroxyl group, an alkyl group having 1 to 20 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, an alkenyloxy group having 2 to 20 carbon atoms, an aryloxy group having 6 to 20 carbon atoms, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a nitrile group, a nitro group, a carboxyl group, and a sulfo group.

[0052] From the viewpoint that the above dye (B) has low reactivity with metals and is unlikely to cause yellowing of the adhesive layer even when the adhesive sheet is attached to a substrate having a metal electrode portion, it is important that one aromatic ring directly bonded to one triazine ring has a hydroxyl group on the carbon adjacent to the bonding position to the triazine ring, and if there is another aromatic ring directly bonded to the triazine ring, the other aromatic ring does not have a hydroxyl group on the carbon adjacent to the bonding position to the triazine ring. Specifically, the following compound manufactured by BASF Japan Ltd. is more preferred from the viewpoint of solubility in organic solvents when preparing the adhesive. Although the exact reason is unknown, when a triazine compound is used that has one, two, or three aromatic rings directly bonded to one triazine ring, in which one of the aromatic rings has a hydroxyl group on the carbon adjacent to the bonding position with the triazine ring, and the other one or two aromatic rings among the aromatic rings also have hydroxyl groups on the carbon adjacent to the bonding position with the triazine ring, a metal complex is easily formed at the hydroxyl group site in the ortho position of the aromatic ring and the nitrogen site of the triazine ring, and the adhesive layer is prone to yellowing.

[0053] [ka]

[0054] Although the details are unknown, dye (A) and dye (B) have a skeletal structure centered on a triazine ring, and it is thought that the inclusion of two types of dye increases the affinity of the dye as a whole with organic solvents and acrylic polymers. In this case, compatibility is improved while maintaining the dye's UV blocking ability, so when an adhesive sheet is made, precipitation due to crystallization in the adhesive layer is less likely to occur. As a result, it is believed that a pressure-sensitive adhesive sheet having excellent stability over time and UV-shielding function can be obtained.

[0055] When these dyes (A) and (B) are combined, one type of each may be used, two or more types of one may be used and one type of the other, or two or more types of both may be used. Also, a third dye that is not classified as dye (A) or dye (B) may be included.

[0056] Examples of the third dye include dyes generally referred to as ultraviolet absorbers, and are not particularly limited thereto. Specifically, examples of the third dye include organic dyes containing a benzophenone skeleton, an oxybenzophenone skeleton, a salicylate skeleton, a cyanoacrylate skeleton, etc., excluding triazine skeletons and benzotriazole skeletons. Other examples include inorganic pigments such as iron oxide, titanium oxide, bismuth oxide, and zinc oxide.

[0057] The dye (A) is preferably added in an amount of 0.1 to 5 parts by mass, more preferably 0.5 to 3 parts by mass, and most preferably 0.8 to 2 parts by mass, per 100 parts by mass of the acrylic polymer (C). This is because adding 0.1 to 5 parts by mass of the dye (A) per 100 parts by mass of the acrylic polymer (C) makes it possible to maintain the compatibility between the acrylic polymer (C) and the dye (A) even in the adhesive layer after the adhesive coating film has been dried to remove the organic solvent, thereby improving the stability over time of the adhesive sheet.

[0058] The dye (B) is preferably contained in an amount 0.1 to 5 times, and more preferably 0.5 to 3 times, the content (parts by mass) of dye (A) as a standard. This is because by containing the dye (B) in an amount 0.1 to 5 times the content of dye (A), the dyes (A) and (B) can be made compatible with each other, crystallization in the adhesive layer is less likely to occur than in the case of a single dye, and the stability over time of the adhesive sheet is improved.

[0059] [Acrylic polymer (C)] The acrylic polymer (C) used in the present invention is a polymer of monomer components mainly containing a monomer having a (meth)acryloyl group, and can also polymerize styrene-based monomers and vinyl monomers having a carboxy group. Examples of the monomer having a (meth)acryloyl group include (meth)acrylate monomers and (meth)acrylamide-based monomers. Examples of the (meth)acrylate monomer include alkyl (meth)acrylates having no functional group and alkyl (meth)acrylates having a hydroxyl group. The polymerization method is preferably solution polymerization, bulk polymerization, emulsion polymerization, suspension polymerization, etc., but solution polymerization is most preferred because of ease of polymerization control.

[0060] Examples of alkyl (meth)acrylates having no functional group include methyl (meth)acrylate, ethyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, sec-butyl (meth)acrylate, t-butyl (meth)acrylate, n-pentyl (meth)acrylate, isopentyl (meth)acrylate, neopentyl (meth)acrylate, n-hexyl (meth)acrylate, cyclohexyl (meth)acrylate, heptyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, n-octyl (meth)acrylate, and isooctyl (meth)acrylate. Acrylate, n-nonyl (meth)acrylate, isononyl (meth)acrylate, t-butylcyclohexyl (meth)acrylate, n-decyl (meth)acrylate, isodecyl (meth)acrylate, n-undecyl (meth)acrylate, n-lauryl (meth)acrylate, n-tridecyl (meth)acrylate, n-tetradecyl (meth)acrylate, n-hexadecyl (meth)acrylate, stearyl (meth)acrylate, isostearyl (meth)acrylate, cyclohexyl (meth)acrylate, 3,5,5-trimethylcyclohexane (meth)acrylate.

[0061] Examples of vinyl monomers having a carboxy group include (meth)acrylic acid, maleic acid, itaconic acid, crotonic acid, and fumaric acid.

[0062] Examples of alkyl (meth)acrylates having a hydroxyl group include 2-hydroxyethyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, 2-(meth)acryloyloxyethyl hexahydrophthalate, 2-(meth)acryloyloxyethyl phthalate, and 2-(meth)acryloyloxyethyl succinate.

[0063] Examples of (meth)acrylamide monomers include N,N-dimethyl(meth)acrylamide, N,N-diethyl(meth)acrylamide, Nt-butyl(meth)acrylamide, N,N-isopropyl(meth)acrylamide, N-(2-hydroxyethyl)acrylamide, N-methoxymethylacrylamide, N-butoxymethylacrylamide, N,N-dimethylaminoethyl(meth)acrylamide, 2-dimethylaminoethyl(meth)acrylate, 2-diethylaminoethyl(meth)acrylate, 2-dimethylaminopropyl(meth)acrylate, diacetoneacrylamide, N-vinylpyrrolidone, and N-vinyl-2-caprolactam. In the present invention, those having a hydroxyl group and an amide group are classified as those having an amide group.

[0064] Examples of the acrylate having an aromatic ring include phenyl (meth)acrylate, benzyl (meth)acrylate, and phenoxyethyl (meth)acrylate. Examples of those having an alkylene oxide chain include butoxyethylene glycol (meth)acrylate, butoxydiethylene glycol (meth)acrylate, methoxytriethylene glycol (meth)acrylate, tetraethylene glycol monomethyl ether (meth)acrylate, hexaethylene glycol monomethyl ether (meth)acrylate, octaethylene glycol monomethyl ether (meth)acrylate, nonaethylene glycol methyl ether (meth)acrylate, heptapropylene glycol monomethyl ether (meth)acrylate, tetraethylene glycol ethyl ether (meth)acrylate, tetraethylene glycol mono(meth)acrylate, hexaethylene glycol mono(meth)acrylate, and octapropylene glycol mono(meth)acrylate. Examples of those having an epoxy group include glycidyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate glycidyl ether, and 3,4-epoxycyclohexylmethyl (meth)acrylate. Other examples include tetrahydrofurfuryl (meth)acrylate, isobornyl (meth)acrylate, dicyclopentenyl (meth)acrylate, dicyclopentanyl (meth)acrylate, and dicyclopentenyloxyethyl (meth)acrylate.

[0065] Among these, from the viewpoint of the durability of the adhesive layer, methyl acrylate, n-butyl acrylate, 4-hydroxybutyl acrylate, acrylic acid, 2-ethylhexyl acrylate, 2-hydroxyethyl acrylate, n-lauryl methacrylate, diacetone acrylamide, dimethyl acrylamide, hydroxyethyl acrylamide, and 2-(dimethylamino)ethyl methacrylate are preferred, and further, from the viewpoint of the solubility of the dye (A), it is particularly preferred that the compound contains diacetone acrylamide.

[0066] The weight average molecular weight of the acrylic polymer (C) is preferably 200,000 to 2,000,000, more preferably 400,000 to 1,500,000, even more preferably 500,000 to 1,500,000, and most preferably 600,000 to 1,300,000. is also preferred. The weight-average molecular weight is preferably 200,000 or more in order to increase the cohesive strength of the adhesive layer, suppress adhesive residue when peeling the adhesive sheet from the adherend, and improve reworkability. Furthermore, the weight-average molecular weight is preferably 2,000,000 or less in order to maintain good cohesive strength and adhesive strength of the adhesive layer. Furthermore, a weight-average molecular weight of 400,000 to 1,500,000 makes it easier to obtain good adhesive retention. The weight-average molecular weight is a value measured in terms of polystyrene by gel permeation chromatography (GPC). The weight-average molecular weight in the present invention was measured using Showa Denko's "GPC101" (column "Shodex KF-806L, KF-804L, KF-802 connected together"; solvent: tetrahydrofuran (THF); measurement temperature: 40°C).

[0067] The glass transition temperature (Tg) of the acrylic polymer (C) is preferably -60°C to 0°C, more preferably -50°C to -20°C. A Tg of -60°C to 0°C makes it easier to obtain high adhesive strength. The Tg of the acrylic polymer (C) is a theoretical value obtained by substituting the Tg of the homopolymer of the monomer into the FOX formula. The homopolymer Tg is according to the Polymer Handbook.

[0068] In the present invention, in addition to the acrylic polymer (C), urethane polymers, polyester polymers, synthetic rubber polymers, natural rubber polymers, silicone polymers, polyvinyl butyral polymers, etc. These other polymers may be used alone or in combination of two or more. In the present invention, it is preferable to use 50% by mass or more of the acrylic polymer (C) in 100% by mass of the total polymers.

[0069] [Hardening agent (D)] The pressure-sensitive adhesive (D) in the present invention contains a curing agent, and the cohesive strength of the pressure-sensitive adhesive is obtained by a curing reaction, thereby making it possible to increase the adhesive strength. The curing agent can be a compound having a functional group reactive with the functional group of the acrylic polymer (C). Specifically, when the acrylic polymer (C) has a hydroxyl group, a (poly)isocyanate-based curing agent, an epoxy-based curing agent, or the like is preferred. When the acrylic polymer (C) has a carboxyl group, an aziridine-based curing agent, a metal chelate-based curing agent, an epoxy-based curing agent, or the like is preferred. Other curing agents that can be used include melamine resins, urea resins, dialdehydes, methylol polymers, and the like. These curing agents may be used alone or in combination of two or more. In the present invention, it is preferable to use a (poly)isocyanate-based curing agent as the curing agent (D) from the viewpoint of ease of adjusting adhesive properties.

[0070] Specific examples of the (poly)isocyanate curing agent include hexamethylene diisocyanate, m-xylylene diisocyanate, p-xylylene diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, diphenylmethane-4,4-diisocyanate, isophorone diisocyanate, 1,3-bis(isocyanatomethyl)cyclohexane, tetramethylxylylene diisocyanate, 1,5-naphthalene diisocyanate, and triphenylmethane triisocyanate. Among these, from the viewpoint of the flexibility of the adhesive, it is particularly preferable to use hexamethylene diisocyanate and m-xylylene diisocyanate.

[0071] Specific examples of epoxy curing agents include N,N,N',N'-tetraglycidyl-m-xylenediamine, (poly)ethylene glycol diglycidyl ether, glycerin diglycidyl ether, glycerin triglycidyl ether, 1,6-hexanediol diglycidyl ether, and the like. Glycidyl ethers and the like.

[0072] The amount of curing agent (D) used is preferably 0.01 to 15 parts by mass, more preferably 0.1 to 10 parts by mass, and even more preferably 0.1 to 5 parts by mass, per 100 parts by mass of acrylic polymer (C). By using 0.01 to 15 parts by mass of curing agent (D) per 100 parts by mass of acrylic polymer (C), the cohesive strength of the adhesive layer can be further improved, and the holding power can be further improved.

[0073] [Other ingredients] The adhesive of the present invention may contain various additives commonly used in adhesives, such as tackifiers, antioxidants, light stabilizers, softeners, coupling agents, curing accelerators, curing retarders, antistatic agents, lubricants, antiblocking agents, and phosphate esters, as long as the additives do not impair the object of the present invention.

[0074] [Adhesive layer, adhesive sheet] The adhesive of the present invention can provide an adhesive sheet by coating an adhesive containing the above-mentioned materials onto a release liner or a substrate, removing the organic solvent, and reacting the acrylic polymer (C) with the curing agent (D) to form an adhesive layer. In particular, the adhesive sheet having the adhesive layer of the present invention is highly transparent, and is therefore excellent in peel resistance and UV resistance, making it suitable for use as an optical adhesive sheet for attachment to touch panels, cover glass, etc.

[0075] Here, the optical pressure-sensitive adhesive sheet includes a single-sided pressure-sensitive adhesive tape in which the pressure-sensitive adhesive layer is formed on one side of a substrate, or a double-sided tape in which the pressure-sensitive adhesive layer is formed on both sides or only one side of a substrate. Alternatively, it may be a so-called cast pressure-sensitive adhesive tape in which the pressure-sensitive adhesive layer is formed between two release liners. In the present invention, the pressure-sensitive adhesive sheet, pressure-sensitive adhesive tape, and pressure-sensitive adhesive film are synonymous terms.

[0076] The thickness of the adhesive layer of the adhesive sheet of the present invention is preferably 2 to 1000 μm, more preferably 5 to 500 μm, more preferably 10 to 300 μm, and most preferably 15 to 150 μm. The adhesive layer may be in the form of a single layer or a laminate of two or more layers.

[0077] The method for forming the adhesive layer is not particularly limited, but a suitable example is a coating method, which can be performed using known coating machines and techniques such as a comma coater, die coater, roll coater, lip coater, reverse coater, gravure coater, bar coater, dip coating, spin coating, silk screen coating, and casting. In a preferred embodiment, the adhesive layer can be formed on one side of the support by applying the adhesive layer-forming coating liquid to the support and then heating and drying the coating film using a hot air oven, an infrared heater, or the like. The adhesive layer-forming coating liquid is preferably prepared by mixing the dye (A), dye (B), acrylic polymer (C), and curing agent (D) using a stirrer such as a disper, mixer, or shaker. When mixing the adhesive layer-forming coating liquid, it is preferable to add a solvent to adjust the processing suitability. Examples of solvents that can be used include 2-butanone, ethyl acetate, cyclohexanone, toluene, and N-methyl-2-pyrrolidone.

[0078] Examples of the release liner include a plastic film or plastic sheet, such as a polyester film such as polyethylene terephthalate, polybutylene terephthalate, or polyethylene naphthalate, or a polyolefin film such as polypropylene or polyethylene, to which a release agent such as silicone resin is applied to provide a release layer. There is no particular limitation on the thickness of the release liner, but it is about 20 to 150 μm.

[0079] In the present invention, the substrate is not particularly limited, but examples thereof include various optical films such as plastic films, antireflection (AR) films, polarizing plates, and retardation plates. Examples of the plastic films include polyvinyl chloride films, polyethylene films, polyethylene terephthalate (PET) films, polyurethane films, nylon films, polyolefin films, triacetyl cellulose films, and cycloolefin films. The thickness of the substrate described above is not particularly limited, but is preferably 10 to 2000 μm.

[0080] The adherend of the pressure-sensitive adhesive layer of the present invention is not particularly limited, but is preferably made of acrylic, polycarbonate, glass, polyethylene terephthalate, or the like, and more preferably has a substrate electrode portion made of metal. Furthermore, the adhesive layer of the present invention is suitable for optical applications, and is preferably used as a laminate for displays that require high quality, such as organic EL display panels, liquid crystal display panels, plasma display panels, touch panels, and electronic paper. [Example]

[0081] The present invention will be specifically described below with reference to examples and comparative examples, but the present invention is not particularly limited to these examples. In the following description, "parts" and "%" represent "parts by mass" and "% by mass", respectively, unless otherwise specified.

[0082] [polymer] [Production example of acrylic polymer (C1)] Using a reactor equipped with a stirrer, reflux condenser, nitrogen inlet tube, thermometer, and dropping tube, 50% of the total amount of 68 parts n-butyl acrylate, 1 part 4-hydroxybutyl acrylate, 23 parts 2-hydroxyethyl acrylate, and 8 parts diacetone acrylamide, along with an appropriate amount of 2,2'-azobisisobutylnitrile as a polymerization initiator and ethyl acetate as a solvent, was charged into a reaction vessel under a nitrogen atmosphere. The remaining 50% of the total amount and an appropriate amount of ethyl acetate were then charged into a dropping vessel. Heating was then initiated, and after confirming the start of the reaction in the reaction vessel, the contents of the dropping tube and an appropriate amount of 2,2'-azobisisobutylnitrile diluted with ethyl acetate were added dropwise under reflux. After the addition was completed, the reaction was continued for 5 hours while maintaining the reflux state, and then the reaction was completed. After cooling, the mixture was diluted with ethyl acetate to obtain a solution of acrylic polymer (C1) with a weight average molecular weight of 650,000 and a glass transition temperature of -36°C (non-volatile content: 40%, viscosity at 25°C: 3000 mPa·s). Moreover, solutions of acrylic polymers (C2) to (C7) were obtained by the same procedure, except that the types and blending amounts of each monomer were changed to those shown in Table 1 below.

[0083] [Table 1]

[0084] [Dye (A-14)] A 300 mL Erlenmeyer flask was charged with 170 parts of chlorobenzene, 43.4 mmol of cyanuric chloride, and 65.1 mmol of aluminum chloride, and the mixture was stirred to form a suspension. Next, while cooling with ice water, 151.8 mmol of 5-acetyl-2-naphthol was added little by little. The mixture was then gradually returned to room temperature and stirred overnight. Meanwhile, a 500 mL beaker was charged with 38.1 parts of water, 10.0 parts of 35% hydrochloric acid, and 45.0 parts of methanol, and the reaction solution was added dropwise little by little. Furthermore, 45.0 parts of methanol were added to the Erlenmeyer flask in multiple portions, and the mixture was then added to the 500 mL beaker while washing. The precipitate was filtered and washed by sprinkling with a mixed solvent of water / methanol = 75 parts / 75 parts. The resulting wet cake was returned to 150 parts of water, reslurried at room temperature for 30 minutes, and filtered. It was then washed by sprinkling with 150 parts of water. The resulting wet cake was dried overnight at 80°C to obtain dye (A-14).

[0085] [Dye (A-25)] A 300 mL Erlenmeyer flask was charged with 170 parts of chlorobenzene, 43.4 mmol of 2-chloro-4,6-di(naphthalen-1-yl)-1,3,5-triazine, and 65.1 mmol of aluminum chloride, and the mixture was stirred to form a suspension. Next, while cooling with ice water, 65.1 mmol of 2-naphthol was added in small portions. The mixture was then gradually returned to room temperature and stirred overnight. Meanwhile, a 500 mL beaker was charged with 38.1 parts of water, 10.0 parts of 35% hydrochloric acid, and 45.0 parts of methanol, and the reaction solution was added dropwise. Furthermore, 45.0 parts of methanol were added to the Erlenmeyer flask in multiple portions, followed by washing, and then added to the 500 mL beaker. The precipitate was filtered and washed by spraying with a 75 / 75 water / methanol mixed solvent. The resulting wet cake was returned to 150 parts of water, reslurried at room temperature for 30 minutes, and filtered. Thereafter, 150 parts of water was sprinkled on the cake for washing, and the resulting wet cake was dried overnight at 80°C to obtain a dye (A-25).

[0086] [Dye (A-26)] A 300 mL Erlenmeyer flask was charged with 170 parts of chlorobenzene, 43.4 mmol of 2,4-dichloro-6-phenyl-1,3,5-triazine, and 65.1 mmol of aluminum chloride, and the mixture was stirred to form a suspension. Next, while cooling with ice water, 108.5 mmol of 2-naphthol was added in small portions. The mixture was then gradually returned to room temperature and stirred overnight. Meanwhile, a 500 mL beaker was charged with 38.1 parts of water, 10.0 parts of 35% hydrochloric acid, and 45.0 parts of methanol, and the reaction solution was added dropwise. Furthermore, 45.0 parts of methanol were added to the Erlenmeyer flask in multiple portions, followed by washing, and then added to the 500 mL beaker. The precipitate was filtered and washed by sprinkling with a 75 / 75 water / methanol mixed solvent. The resulting wet cake was returned to 150 parts of water, reslurried at room temperature for 30 minutes, and filtered. It was then washed by sprinkling with 150 parts of water. The resulting wet cake was dried overnight at 80°C to obtain dye (A-26).

[0087] [Dye (A-28)] Dye (A-28) was obtained in the same manner as in the production of dye (A-25), except that 2-chloro-4,6-diphenyl-1,3,5-triazine was used instead of 2-chloro-4,6-di(naphthalen-1-yl)-1,3,5-triazine. For example, dye (A-28) was prepared by adding 420 mmol of methyl 2-hydroxy-1-naphthoate to a 500 mL Erlenmeyer flask and heating to 90°C with stirring. Next, 128 mmol of benzamidine hydrochloride and 26 parts of a 30% solution of sodium methylate were added and stirred at 90°C for 22 hours. Then, 200 parts of methanol were added, cooled to room temperature, and filtered. The resulting wet cake was added back to 150 parts of methanol and reslurried at room temperature for 30 minutes, followed by filtration. The resulting wet cake was then washed by sprinkling with 150 parts of methanol. It can also be obtained by drying the resulting wet cake overnight at 80°C.

[0088] [Dye (A-31)] An ultraviolet absorber (A-31) was obtained in the same manner as in the production of dye (A-25), except that 2-chloro-4,6-dimethoxy-1,3,5-triazine was used instead of 2-chloro-4,6-di(naphthalen-1-yl)-1,3,5-triazine.

[0089] [Example 1] [Adhesive manufacturing example] 5 parts of (A-28) as dye (A), 5 parts of Tinuvin 400 (non-volatile content: 85%, manufactured by BASF Japan Ltd.) as dye (B) (based on non-volatile content), and 58 parts of ethyl acetate as solvent were added in sequence while stirring with a disperser, and the mixture was stirred until sufficiently uniform. The mixture was stirred. 250 parts of a solution containing 100 parts of an acrylic polymer (C1) and 2 parts of a solution containing 1 part of Curing 1 (hexamethylene diisocyanate) as a curing agent (D) were added, and the mixture was stirred with a disperser, and stirred until the mixture was sufficiently uniform. The mixture was then filtered through a membrane filter with a pore size of 10 μm to remove coarse foreign matter that could cause coating unevenness, yielding Pressure-Sensitive Adhesive 1 with a non-volatile content of 35%.

[0090] [Adhesive sheet manufacturing example] PSA 1 was applied to a 50 μm thick release liner so that the thickness after drying would be 50 μm, and after drying for 3 minutes in a hot air oven at 100°C, a 38 μm release liner was attached to the adhesive layer side. The sheet was then aged at room temperature for 7 days to allow the reaction of the adhesive layer to proceed, yielding an adhesive sheet. The yellowing resistance, UV shielding property, stability over time, and adhesive strength were evaluated according to the methods described below. Each evaluation was made on a four-point scale, with the most excellent being ⊚, the next best being ◯, then good being △, and the target performance not being achieved being ×. Note that films with all the better △ ratings for each performance category correspond to the present invention.

[0091] [Examples 2 to 24], [Comparative Examples 1 to 7] Pressure-sensitive adhesives 2 to 31 and pressure-sensitive adhesive sheets were prepared in the same manner as for Pressure-sensitive Adhesive 1, except that the materials shown in Tables 2 and 3 were used in the amounts shown in Tables 4 and 5, and were evaluated in the same manner. In Tables 4 and 5, the amount of each dye is the amount converted into nonvolatile matter, the amount of the acrylic polymer (C) and curing agent is the amount as a solution, and blank spaces indicate that no compounding is performed.

[0092] [Table 2]

[0093] [Table 3]

[0094] [Table 4]

[0095] [Table 5]

[0096] [Evaluation method and criteria] [Yellowing resistance] A copper-deposited PET film (50 μm thick, manufactured by Toray Industries, Inc.) was prepared by vapor-depositing copper onto the PET film. The 38 μm release liner was peeled off from the adhesive sheet, and the sheet was then bonded to the vapor-deposited copper surface of the copper-deposited PET. This sheet was then cut into 3 cm × 10 cm pieces, and the 50 μm release liner on the other side of the adhesive sheet was peeled off. A 2 kg load was applied to the exposed adhesive layer using a tape pressure roller, and a 1 mm thick glass plate was then pressed against the exposed adhesive layer to produce a four-layer laminate: PET / vapor-deposited copper / adhesive layer / glass plate. Using a spectrophotometer SE-6000 manufactured by Nippon Denshoku Industries Co., Ltd., the color was measured at any five points on the glass plate side of the laminate under light source conditions of C / 2°, and the average L*a*b* values ​​were calculated. Next, this laminate was left to stand for 30, 50, and 80 hours in an environment of 85°C and 85% humidity, and then the color was measured at five arbitrary points from the glass plate side in the same manner, and the average L*a*b* values ​​were calculated. The change in color difference before and after leaving the sheet to stand was taken as ΔE. If the color difference ΔE is 5.0 or less, it is considered that no color change occurs because copper ions do not migrate from the vapor deposition layer to the adhesive layer. The evaluation criteria are as follows, with △ or better being considered good. ◎: Color difference ΔE after 80 hours is 5.0 or less 〇: Color difference ΔE after 50 hours is 5.0 or less △: Color difference ΔE after 30 hours is 5.0 or less ×: Color difference ΔE after 30 hours is greater than 5.0

[0097] [UV shielding property] The pressure-sensitive adhesive sheet was cut into 2 cm x 5 cm pieces, and a 1 mm thick glass plate was attached to the surface from which the 38 μm release liner had been peeled off, and the sheet was pressed with a 2 kg load using a tape pressure roller. The 50 μm release liner on the other side of the pressure-sensitive adhesive sheet was then peeled off to expose the adhesive layer, and the UV transmittance from 200 nm to 400 nm was measured. The measurement was performed using a V-570 UV-visible spectrophotometer manufactured by JASCO Corporation. The evaluation criteria were as follows, with △ or better being considered good. ◎: Transmittance is less than 3% across the entire range from 200nm to 400nm ○: Transmittance is 3% or more and less than 5% across the entire range from 200nm to 400nm △: Transmittance is 5% or more and less than 10% across the entire range from 200nm to 400nm ×: Transmittance is 10% or more across the entire range from 200 nm to 400 nm

[0098] [Stability over time] The 38 μm release liner was peeled off from the pressure-sensitive adhesive sheet, and the sheet was laminated to a PET film (Lumirror T60, 50 μm thick, manufactured by Toray Industries, Inc.) This sheet was then cut to 3 cm × 10 cm, and a 1 mm thick glass plate was attached to the opposite side of the pressure-sensitive adhesive sheet, and the sheets were pressed together using a tape pressing roller with a 2 kg load to produce a laminate with a three-layer structure of PET / pressure-sensitive adhesive layer / glass plate. This laminate was left to stand in an environment at 100°C for up to 120 hours, and then observed using an optical microscope at 50x magnification to determine whether there were any crystallized dye particles of 0.5 mm or more in the adhesive layer. A similar laminate was also left to stand in an environment at -40°C, and similar precipitates were observed. The evaluation criteria were as follows, with fair or better being considered good. ◎: Under any environment, there was one or less precipitate after 120 hours ○: Under any environment, there was one or less precipitate after 80 hours △: Under any environment, there was one or less precipitate after 50 hours. ×: One or more precipitates were observed after 50 hours under any environment.

[0099] [Adhesive strength] The 38 μm release liner was peeled off from the pressure-sensitive adhesive sheet, and the sheet was attached to a PET film (Lumirror T60, manufactured by Toray Industries, Inc., thickness 50 μm). The adhesive sheet was cut into 1 / 4" thick pieces, and the 50μm release liner on the other side was peeled off to expose the adhesive layer, which was then attached to a glass plate and pressed with a 2kg load using a tape pressure roller. After leaving the sheet standing for 24 hours at 23°C and 50% relative humidity, the adhesive strength was measured using a tensile tester at a peel speed of 300mm / min and a peel angle of 180°. The evaluation criteria were as follows, with a score of △ or better being considered good. ◎: Adhesive strength is 1400gf / 25mm or more 〇: Adhesive strength is 1200gf / 25mm or more, less than 1400gf / 25mm △: Adhesive strength is 1000gf / 25mm or more, less than 1200gf / 25mm ×: Adhesive strength is less than 1000gf / 25mm

[0100] As shown in Table 4, it was found that the adhesive layer made using the adhesive of the present invention has excellent resistance to yellowing even when in contact with metal, excellent UV blocking properties over a wide range from the short wavelength region around 200 nm to the long wavelength region close to visible light, excellent stability over time, and excellent adhesive strength. On the other hand, as shown in Table 5, the adhesive layers formed using the adhesives of Comparative Examples 1 to 7 were unable to achieve a satisfactory balance of high levels of yellowing resistance, UV blocking properties, stability over time, and adhesive strength.

Claims

1. a dye (A) which is a triazine compound having at least one triazine ring and one, two or three naphthalene rings directly bonded to one triazine ring; a dye (B) having at least one triazine ring and possibly having three or less aromatic rings directly bonded to one triazine ring, wherein one of the aromatic rings has a hydroxyl group on a carbon atom adjacent to the bonding position to the triazine ring, and when another aromatic ring is present among the aromatic rings, the other aromatic ring does not have a hydroxyl group on a carbon atom adjacent to the bonding position to the triazine ring; an acrylic polymer (C); a curing agent (D), Contains adhesive. (However, the dye (B) is other than the dye (A).)

2. The adhesive according to claim 1, wherein the dye (A) comprises a compound selected from the group consisting of the following general formulas (1), (2), and (3): 【Chemistry 1】 (In general formulas (1) to (3), R １ｂ ~R １ｇ , R ２ａ ~R ２ｇ , R ３ａ ~R ３ｇ each independently represents a hydrogen atom, a hydroxyl group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a nitrile group, a nitro group, a sulfo group, R ７ , Ar １ , and groups represented by the following general formulas (4-1) to (4-3). R ７ represents an alkyl group having 1 to 20 carbon atoms which may have a substituent, an alkenyl group having 2 to 20 carbon atoms which may have a substituent, an alkoxy group having 1 to 20 carbon atoms which may have a substituent, or an alkenyloxy group having 2 to 20 carbon atoms which may have a substituent, a functional group in which carbon atoms of an optionally substituted alkyl group having 1 to 20 carbon atoms are linked by one or more of -O-, -CO-, -COO-, -OCO-, -CONH-, or -NHCO-; a functional group in which carbon atoms of an optionally substituted alkenyl group having 2 to 20 carbon atoms are linked together by one or more of -O-, -CO-, -COO-, -OCO-, -CONH-, or -NHCO-, The substituent is selected from the group consisting of a hydroxyl group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a nitrile group, a nitro group, a carboxyl group, and a sulfo group. Ar １ represents an aryl group having 6 to 20 carbon atoms which may have a substituent, or an aryloxy group having 6 to 20 carbon atoms which may have a substituent, and the substituent is selected from the group consisting of a hydroxyl group, an alkyl group having 1 to 20 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, an alkenyloxy group having 2 to 20 carbon atoms, an aryloxy group having 6 to 20 carbon atoms, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a nitrile group, a nitro group, a carboxyl group, and a sulfo group. In addition, in the general formulas (2) to (3), R ４ , R ５ , R ６ is a hydroxyl group, R ７ or Ar １ is. 【Chemistry 2】 In general formula (4-1), X １ is —CO—, —COO—, —OCO—, —CONH—, or —NHCO—. ８ represents a hydrogen atom, a hydroxyl group, R ７ or Ar １ In the formula (4-1), * represents the bonding site with the naphthalene ring of the formulae (1) to (3). 【Transformation 3】 In general formula (4-2), X ２ , X ３ are each independently —CO—, —COO—, —OCO—, —CONH—, or —NHCO—. ９ is an arylene group having 6 to 20 carbon atoms. １０ is R ７ or Ar １ In the formula (4-2), * represents the bonding site with the naphthalene ring of the formulae (1) to (3). 【Chemistry 4】 In general formula (4-3), X ４ , X ５ are each independently —CO—, —COO—, —OCO—, —CONH—, or —NHCO—. １１ is a linear or branched alkylene group having 1 to 20 carbon atoms, or an arylene group having 6 to 20 carbon atoms. １２ is R ７ or Ar １ n is 1 to 20. However, * in general formula (4-3) represents the bonding site with the naphthalene ring of general formulas (1) to (3).

3. The dye (A) is In the case of general formula (1), R ２ａ and R ３ａ is not a hydroxyl group, In the case of general formula (2), R ２ａ is not a hydroxyl group, but R ４ is R ７ or Ar １ and Ar １ However, in the case of an aryl group having 6 to 20 carbon atoms which may have a substituent, or an aryloxy group having 6 to 20 carbon atoms which may have a substituent, the carbon atom adjacent to the bonding position to the triazine ring does not have a hydroxyl group, In the case of general formula (3), R ５ , R ６ are each independently R ７ or Ar １ and Ar １ is an optionally substituted aryl group having 6 to 20 carbon atoms, or an optionally substituted aryloxy group having 6 to 20 carbon atoms, the carbon atom adjacent to the bonding position to the triazine ring does not have a hydroxyl group.

4. An adhesive described in any one of claims 1 to 3, wherein the dye (A) is any compound selected from the following formulas: 【Transformation 6】 【Transformation 7】 【Transformation 8】 【Chemistry 9】 【Chemistry 10】 【Chemistry 11】

5. The pressure-sensitive adhesive according to any one of claims 1 to 4, wherein the dye (B) is a compound represented by the following general formula (12): 【Chemistry 12】 In general formula (12), R 1 represents an alkyl group having 1 to 20 carbon atoms which may have a substituent, or an alkenyl group having 2 to 20 carbon atoms which may have a substituent, a functional group in which carbon atoms of an optionally substituted alkyl group having 1 to 20 carbon atoms are linked by one or more -O-, -CO-, -COO-, -OCO-, -CONH-, or -NHCO-; a functional group in which carbon atoms of an optionally substituted alkenyl group having 2 to 20 carbon atoms are linked together by one or more of -O-, -CO-, -COO-, -OCO-, -CONH-, or -NHCO-; The substituent is 、 selected from the group consisting of a hydroxyl group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a nitrile group, a nitro group, a carboxyl group, and a sulfo group; Ar １ , Ar 2 are each independently an aryl group having 6 to 20 carbon atoms which may have a substituent, or an aryloxy group having 6 to 20 carbon atoms which may have a substituent, and the substituents are 、 It is selected from the group consisting of a hydroxyl group, an alkyl group having 1 to 20 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, an alkenyloxy group having 2 to 20 carbon atoms, an aryloxy group having 6 to 20 carbon atoms, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a nitrile group, a nitro group, a carboxyl group, and a sulfo group.

6. An adhesive described in any one of claims 1 to 5, wherein the dye (B) is any compound selected from the following formulas: 【Chemistry 13】

7. The pressure-sensitive adhesive according to any one of claims 1 to 6, wherein the acrylic polymer (C) is a copolymer of an amide acrylic monomer and another monomer.

8. The pressure-sensitive adhesive according to claim 7, wherein the amide-based acrylic monomer is diacetone acrylamide and / or N-vinylpyrrolidone.

9. The pressure-sensitive adhesive according to any one of claims 1 to 8, wherein the acrylic polymer (C) is a polymer having a hydroxyl group.

10. The pressure-sensitive adhesive according to any one of claims 1 to 9, wherein the curing agent (D) is an isocyanate-based curing agent.

11. An adhesive layer which is a cured product of the adhesive according to any one of claims 1 to 10.

12. The adhesive layer according to claim 11, wherein the light transmittance is 5% or less over the entire range of 200 to 400 nm.

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