Adhesive sheet

Abstract

The adhesive sheet (10) contains a base polymer and a metal complex salt black dye. The acid value of the base polymer is 50 mgKOH / g or less.

Description

Technical Field

[0001] This invention relates to adhesive sheets. Background Technology

[0002] In the manufacturing process of display panels such as organic EL panels, adhesive sheets are used as bonding materials between components. As such adhesive sheets, black adhesive sheets incorporating black pigments are known from the viewpoints of design, light-shielding, or anti-reflective properties. Such adhesive sheets are described, for example, in Patent Document 1 below.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2013-32430 Summary of the Invention

[0006] The problem that the invention aims to solve

[0007] The adhesive sheet described in Patent Document 1 contains a base polymer and a black pigment. Carbon black is preferably used as the black pigment. However, the black pigment is dispersed without dissolving in the adhesive sheet. Therefore, the black pigment increases the haze of the adhesive sheet. In a black adhesive sheet, a lower haze is preferred to ensure good designability, light-blocking properties, or anti-reflective properties.

[0008] As the black component in the adhesive sheet, black dye can be considered instead of black pigment as in Patent Document 1. However, in the past, the black weather resistance of black dyes has been reduced.

[0009] This invention provides adhesive sheets suitable for black pigments that ensure good lightfastness while suppressing haze.

[0010] means for solving problems

[0011] The present invention [1] includes an adhesive sheet, wherein the adhesive sheet contains a base polymer with an acid value of less than 50 mg KOH / g and a metal complex salt black dye.

[0012] The present invention [2] includes the adhesive sheet described in [1] above, wherein the metal complex salt black dye comprises at least one metal selected from the group consisting of chromium and copper.

[0013] The present invention [3] includes the adhesive sheet described in [1] or [2] above, wherein the metal complex salt black dye includes an azo dye compound as the dye compound.

[0014] The present invention [4] includes the adhesive sheet described in [3] above, wherein the azo dye compound is an aromatic azo dye compound.

[0015] The present invention [5] comprises the adhesive sheet described in any one of [1] to [4] above, wherein the metal complex salt black dye has a molecular weight of 400 or more.

[0016] The present invention [6] includes the adhesive sheet described in any one of [1] to [5] above, wherein the adhesive sheet is... Transmitted hues in the color system Values ​​below 0.

[0017] The present invention [7] includes the adhesive sheet described in any one of [1] to [6] above, wherein the haze of the adhesive sheet is 3.0% or less.

[0018] Invention Effects

[0019] The adhesive sheet of the present invention, as described above, contains a metal complex salt black dye as the black component. The dye is soluble in the adhesive composition forming the adhesive sheet during the manufacturing process. Therefore, compared to pigments, the dye can be well dispersed in the adhesive sheet. Thus, the presence of dye as the black component in the adhesive sheet is suitable for reducing the haze of the adhesive sheet.

[0020] Furthermore, in the adhesive sheet of the present invention, as described above, the acid value of the base polymer is 50 mg KOH / g or less. The fact that the adhesive sheet contains a base polymer with a low acid value of 50 mg KOH / g or less is beneficial for ensuring the stability of the coordination bonds between the metal and the dye compound in the metal complex salt black dye (the higher the acid value of the base polymer, the more damaged the coordination bonds). Stabilization of the metal complex salt black dye helps ensure its lightfastness.

[0021] Therefore, the adhesive sheet of the present invention is suitable for ensuring good black lightfastness while suppressing haze. Attached Figure Description

[0022] Figure 1 This is a cross-sectional schematic diagram of one embodiment of the adhesive sheet of the present invention.

[0023] Figure 2 express Figure 1 An example of a method for manufacturing an optical adhesive sheet. Figure 2 A represents the film formation process of the adhesive composition. Figure 2 B indicates the basic adhesive sheet formation process. Figure 2 C represents a peeling process for a peeling liner. Figure 2 D indicates the process of supplying the added components to the base adhesive sheet. Figure 2 E indicates the process of attaching the release liner to the adhesive sheet. Detailed Implementation

[0024] like Figure 1 As shown, the adhesive sheet 10, as an embodiment of the present invention, has a sheet shape with a predetermined thickness and extends in a direction orthogonal to the thickness direction H (plane direction). The adhesive sheet 10 has an adhesive surface 11 (first adhesive surface) and an adhesive surface 12 (second adhesive surface) opposite to the adhesive surface 11. Figure 1 This illustration shows a state where release liner 21 and 22 are attached to the adhesive surfaces 11 and 12 of the adhesive sheet 10. Release liner 21 is peelably in contact with the adhesive surface 11. Release liner 22 is peelably in contact with the adhesive surface 12. Release liner 21 and 22 are peeled off from the adhesive sheet 10 at predetermined times during use.

[0025] In this embodiment, the adhesive sheet 10 is a sheet-like pressure-sensitive adhesive formed from an adhesive composition. The adhesive composition contains a base polymer with an acid value of less than 50 mg KOH / g and a metal complex salt black dye. That is, the adhesive sheet 10 contains a base polymer with an acid value of less than 50 mg KOH / g and a metal complex salt black dye.

[0026] Examples of base polymers include acrylic polymers, polyurethane polymers, polyamide polymers, and polyvinyl ether polymers. Base polymers can be used alone or in combination of two or more. From the viewpoint of ensuring good adhesion and transparency in the adhesive sheet 10, acrylic polymers are preferred as base polymers.

[0027] Acrylic polymers are copolymers containing monomers of (meth)acrylate in a proportion of 50% or more by mass. "(Meth)acrylate" refers to acrylic acid and / or methacrylic acid.

[0028] (Meth)acrylates are preferably alkyl (meth)acrylates, and more preferably alkyl (meth)acrylates having alkyl groups having 1 to 20 carbon atoms. Examples of such alkyl methacrylates include: methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, sec-butyl methacrylate, tert-butyl methacrylate, pentyl methacrylate, isoamyl methacrylate, neopentyl methacrylate, hexyl methacrylate, heptyl methacrylate, 2-ethylhexyl methacrylate, n-octyl methacrylate, isooctyl methacrylate, nonyl methacrylate, isononyl methacrylate, n-decyl methacrylate, isodecyl methacrylate, undecyl methacrylate, dodecyl methacrylate, n-tridecyl methacrylate, isotridecyl methacrylate, tetradecyl methacrylate, isotetradecyl methacrylate, pentadecyl methacrylate, n-octadecyl methacrylate, isooctadecyl methacrylate, and nonadecanyl methacrylate. Alkyl methacrylates can be used alone or in combination with two or more. Alkyl methacrylates are preferably at least one selected from the group consisting of methyl methacrylate (MMA), n-butyl acrylate (BA), and 2-ethylhexyl acrylate (2EHA).

[0029] The proportion of alkyl (meth)acrylate in the monomer component is preferably 55% to 99.9% by mass, more preferably 60% to 99.5% by mass, and even more preferably 62% to 99% by mass. The proportion of alkyl (meth)acrylate in the monomer component is preferably 55% by mass or more, more preferably 60% by mass or more, and even more preferably 62% by mass or more. When the proportion of alkyl (meth)acrylate is at or above the aforementioned lower limit, basic properties such as adhesion can be appropriately exhibited in the adhesive sheet 10. Furthermore, the proportion of alkyl (meth)acrylate in the monomer component is, for example, 99.9% by mass or less, 99.5% by mass or less, or 99% by mass or less.

[0030] The monomer component may include copolymerizable monomers capable of copolymerizing with alkyl (meth)acrylates. Examples of copolymerizable monomers include, for example, monomers containing polar groups. Examples of monomers containing polar groups include, for example, hydroxyl-containing monomers, monomers having a nitrogen-containing ring, and carboxyl-containing monomers. Copolymerizable monomers may be used alone or in combination of two or more. Monomers containing polar groups contribute to ensuring the cohesiveness of acrylic polymers and the modification of acrylic polymers. The monomers containing polar groups are preferably at least one selected from the group consisting of hydroxyl-containing monomers and monomers having a nitrogen-containing ring.

[0031] Examples of hydroxyl-containing monomers include: 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, 8-hydroxyoctyl (meth)acrylate, 10-hydroxydecyl (meth)acrylate, and 12-hydroxylaurate (meth)acrylate. The hydroxyl-containing monomer is preferably at least one selected from the group consisting of 2-hydroxyethyl acrylate (2HEA), 4-hydroxyethyl acrylate (4HEA), and 4-hydroxybutyl acrylate (4HBA).

[0032] The proportion of hydroxyl-containing monomers in the monomer component is preferably 0.1% to 30% by mass, more preferably 0.5% to 20% by mass, and even more preferably 1% to 15% by mass. The proportion of hydroxyl-containing monomers in the monomer component is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, and even more preferably 1% by mass or more. When this proportion of hydroxyl-containing monomers is at or above the aforementioned lower limit, the cohesive force of the adhesive sheet 10 can be ensured, and the adhesion force of the adhesive sheet 10 to the adhered object can also be ensured. Furthermore, the proportion of hydroxyl-containing monomers in the monomer component is preferably 30% by mass or less, more preferably 20% by mass or less, and even more preferably 15% by mass or less. When this proportion of hydroxyl-containing monomers is at or below the aforementioned upper limit, the polarity of the acrylic polymer (which relates to the compatibility of various additive components in the adhesive sheet 10 with the acrylic polymer) can be appropriately adjusted.

[0033] Examples of monomers having a nitrogen-containing ring include: N-vinyl-2-pyrrolidone, N-methylvinylpyrrolidone, N-vinylpyridine, N-vinylpiperidone, N-vinylpyrimidine, N-vinylpiperazine, N-vinylpyrrazine, N-vinylpyrrole, N-vinylimidazolium, N-vinylpyrazole, N-(meth)acryloyl-2-pyrrolidone, N-(meth)acryloylpiperidine, N-(meth)acryloylpyrrolidine, N-vinylmorpholine, N-vinyl-3-morpholinone, N-vinyl-2-caprolactam, N-vinyl-1,3-pyrazin-2-one, N-vinyl-3,5-morpholinedione, N-vinylpyrazole, N-vinylisopyrazole, N-vinylthiazole, N-vinylisothiazole, and acryloylmorpholine. N-vinyl-2-pyrrolidone (NVP) is preferred as the monomer having a nitrogen-containing ring.

[0034] The proportion of monomers containing nitrogen-containing rings in the monomer composition is preferably 1% to 30% by mass, more preferably 5% to 20% by mass, and even more preferably 8% to 17% by mass. The proportion of monomers containing nitrogen-containing rings in the monomer composition is preferably 1% or more by mass, more preferably 5% or more by mass, and even more preferably 8% or more by mass. When this proportion of monomers containing nitrogen-containing rings is at or above the aforementioned lower limit, the cohesive force of the adhesive sheet 10 can be ensured, and the adhesion force of the adhesive sheet 10 to the adhered object can also be ensured. Furthermore, the proportion of monomers containing nitrogen-containing rings in the monomer composition is preferably 30% or less by mass, more preferably 20% or less by mass, and even more preferably 17% or less by mass. When this proportion of monomers containing nitrogen-containing rings is at or below the aforementioned upper limit, the glass transition temperature of the acrylic polymer can be appropriately adjusted, and the polarity of the acrylic polymer (which relates to the compatibility of various additive components in the adhesive sheet with the acrylic polymer) can be appropriately adjusted.

[0035] Examples of carboxyl-containing monomers include: acrylic acid, methacrylic acid, carboxyethyl acrylate, carboxypentyl acrylate, itaconic acid, maleic acid, fumaric acid, crotonic acid, and isocrotonic acid.

[0036] The proportion of carboxyl-containing monomers in the monomer component is preferably 0.0% to 3% by mass, more preferably 0.0% to 1% by mass, even more preferably 0.0% to 0.5% by mass, and even more preferably 0.0% to 0.1% by mass. The proportion of carboxyl-containing monomers in the monomer component is preferably 3% by mass or less, more preferably 1% by mass or less, even more preferably 0.5% by mass or less, even more preferably 0.1% by mass or less, and particularly preferably 0.0% by mass. When the proportion of carboxyl-containing monomers in the monomer component is below the above-mentioned upper limit, the acid value of the base polymer can be adjusted to 50 mg KOH / g or less. Furthermore, when the proportion of carboxyl-containing monomers in the monomer component is below the above-mentioned upper limit, acid-induced corrosion in the adhered material of the adhesive sheet 10 can be suppressed.

[0037] The monomer component may include other copolymerizable monomers. Examples of other copolymerizable monomers include: acid anhydride monomers, sulfonic acid monomers, phosphate monomers, epoxy monomers, cyano monomers, alkoxy monomers, and aromatic vinyl compounds.

[0038] Acrylic polymers can be formed by polymerizing the aforementioned monomer components. Examples of polymerization methods include solution polymerization, emulsion polymerization, bulk polymerization, and photopolymerization. A polymerization initiator is used depending on the polymerization method. Examples of polymerization initiators include thermal polymerization initiators and photopolymerization initiators. The amount of polymerization initiator used relative to 100 parts by mass of the monomer component is, for example, 0.05 parts by mass or more, and, for example, 1 part by mass or less.

[0039] Examples of thermal polymerization initiators include azo polymerization initiators and peroxide polymerization initiators. Examples of azo polymerization initiators include 2,2'-azobisisobutyronitrile, 2,2'-azobis(2-methylbutyronitrile), and dimethyl 2,2'-azobis(2-methylpropionic acid). Examples of peroxide polymerization initiators include benzoyl peroxide, tert-butyl maleate peroxide, and lauroyl peroxide.

[0040] Examples of photopolymerization initiators include: free radical photopolymerization initiators, cationic photopolymerization initiators, and anionic photopolymerization initiators. Examples of free radical photopolymerization initiators include: acylphosphine oxide photopolymerization initiators, benzoin ether photopolymerization initiators, acetophenone photopolymerization initiators, α-keto alcohol photopolymerization initiators, aromatic sulfonyl chloride photopolymerization initiators, photoactive oxime photopolymerization initiators, benzoin photopolymerization initiators, benzoyl photopolymerization initiators, benzophenone photopolymerization initiators, ketal photopolymerization initiators, and thioxanone photopolymerization initiators.

[0041] From the viewpoint of ensuring the cohesiveness of the adhesive sheet 10, the weight-average molecular weight of the base polymer is preferably 100,000 to 5,000,000, more preferably 300,000 to 3,000,000, and even more preferably 500,000 to 2,000,000. The weight-average molecular weight of the base polymer is preferably 100,000 or more, more preferably 300,000 or more, and even more preferably 500,000 or more. When the weight-average molecular weight of the base polymer is at or above the aforementioned lower limit, the cohesiveness of the adhesive sheet 10 can be ensured. The weight-average molecular weight of the base polymer is preferably 5,000,000 or less, more preferably 3,000,000 or less, and even more preferably 2,000,000 or less. When the weight-average molecular weight of the base polymer is below the aforementioned upper limit, the flexibility of the adhesive sheet 10 can be ensured. The weight-average molecular weight of the acrylic polymer is determined by gel permeation chromatography (GPC) and calculated by conversion to polystyrene.

[0042] The glass transition temperature (Tg) of the base polymer is preferably below 0°C, more preferably below -10°C, and even more preferably below -20°C. This glass transition temperature is, for example, above -80°C. That is, the glass transition temperature of the base polymer is preferably between -80°C and 0°C, more preferably between -80°C and -10°C, and even more preferably between -80°C and -20°C.

[0043] From the viewpoint of ensuring the cohesiveness of the adhesive sheet 10, the base polymer preferably has a crosslinked structure. As methods for introducing the crosslinked structure into the base polymer, examples include the following first and second methods. In the first method, a base polymer having functional groups capable of reacting with a crosslinking agent and a crosslinking agent are incorporated into the adhesive composition, and the base polymer and the crosslinking agent react in the adhesive sheet. In the second method, a multifunctional compound (crosslinking agent) such as a multifunctional monomer is included in the monomer component forming the base polymer, and a base polymer with a branched structure (crosslinked structure) introduced into the polymer chain is formed by the polymerization of this monomer component. These methods can be used in combination.

[0044] As a crosslinking agent used in the first method described above, examples include compounds that react with functional groups (hydroxyl and carboxyl groups, etc.) contained in the base polymer. Examples of such crosslinking agents include isocyanate crosslinking agents, epoxy crosslinking agents, α-azoline crosslinking agents, aziridine crosslinking agents, carbodiimide crosslinking agents, and metal chelate crosslinking agents; isocyanate crosslinking agents are preferred. The crosslinking agent can be used alone or in combination of two or more.

[0045] Examples of isocyanate crosslinking agents include: toluene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, phenylenediamine diisocyanate, hydrogenated phenylenediamine diisocyanate, and diphenylmethane diisocyanate. Derivatives of these isocyanates can also be listed as isocyanate crosslinking agents. Examples of isocyanate derivatives include isocyanurate modified forms and polyol modified forms. Commercially available isocyanate crosslinking agents include CORONATE L (trimethylolpropane adduct of toluene diisocyanate, manufactured by Tosoh), CORONATE HL (trimethylolpropane adduct of hexamethylene diisocyanate, manufactured by Tosoh), CORONATE HX (isocyanurate form of hexamethylene diisocyanate, manufactured by Tosoh), and TAKENATED 110N (trimethylolpropane adduct of phenylenediamine diisocyanate, manufactured by Mitsui Chemicals).

[0046] From the viewpoint of ensuring the cohesiveness of the adhesive sheet 10, the amount of crosslinking agent in the first method is preferably 0.01 parts by mass or more, more preferably 0.05 parts by mass or more, and even more preferably 0.07 parts by mass or more, relative to 100 parts by mass of the base polymer. From the viewpoint of ensuring good adhesion in the adhesive sheet 10, the amount of crosslinking agent relative to 100 parts by mass of the base polymer is preferably 10 parts by mass or less, more preferably 5 parts by mass or less, and even more preferably 3 parts by mass or less. From the viewpoint of balancing the cohesiveness of the adhesive sheet 10 and good adhesion, the amount of crosslinking agent relative to 100 parts by mass of the base polymer is preferably 0.01 to 10 parts by mass, more preferably 0.05 to 5 parts by mass, and even more preferably 0.07 to 3 parts by mass.

[0047] In the second method described above, monofunctional monomers and polyfunctional compounds (crosslinking agents) can be polymerized in a single step or in multiple steps. In the multi-step polymerization method, the monofunctional monomers are first polymerized (prepolymerization), thereby preparing a prepolymer composition containing a portion of the polymer (a mixture of low-degree polymers and unreacted monomers). Then, after adding the polyfunctional compound (crosslinking agent) to the prepolymer composition, the portion of the polymer is polymerized with the polyfunctional compound (main polymerization).

[0048] Examples of multifunctional compounds include multifunctional monomers and multifunctional oligomers containing two or more olefinic unsaturated double bonds in one molecule. Examples of multifunctional monomers include multifunctional (meth)acrylates.

[0049] Examples of polyfunctional (meth)acrylates include difunctional (meth)acrylates, trifunctional (meth)acrylates, and polyfunctional (meth)acrylates with four or more functions.

[0050] Examples of bifunctional (meth)acrylates include: ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, tetraethylene glycol dimethacrylate, 1,6-hexanediol dimethacrylate, 1,9-nonanediol dimethacrylate, glycerol dimethacrylate, ethoxylated bisphenol A dimethacrylate (BPAEODE), and neopentyl glycol dimethacrylate.

[0051] Examples of trifunctional (meth)acrylates include: trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, and tri(acryloyloxyethyl) isocyanurate.

[0052] Examples of polyfunctional (meth)acrylates with more than four functions include: di(trimethylolpropane)tetra(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol monohydroxypenta(meth)acrylate, alkyl-modified dipentaerythritol penta(meth)acrylate, and dipentaerythritol hexa(meth)acrylate.

[0053] Examples of multifunctional oligomers include: urethane (meth)acrylate oligomers, polyester (meth)acrylate oligomers, polyether (meth)acrylate oligomers, polyol (meth)acrylate oligomers, epoxy (meth)acrylate oligomers, polyethylene glycol di(meth)acrylate, and polypropylene glycol di(meth)acrylate.

[0054] The multifunctional compound used as the crosslinking agent in the second method can be used alone or in combination with two or more. Preferably, at least one compound selected from the group consisting of 1,6-hexanediol diacrylate (HDDA) and dipentaerythritol hexaacrylate (DPHA) is used.

[0055] The content of the base polymer in the adhesive sheet 10 is preferably 80% to 99.9% by mass, more preferably 90% to 99.5% by mass, and even more preferably 95% to 99.0% by mass.

[0056] The content of the base polymer in the adhesive sheet 10 is preferably 80% by mass or more, more preferably 90% by mass or more, and even more preferably 95% by mass or more. When the content of the base polymer is at or above the aforementioned lower limit, the adhesive sheet 10 can appropriately exhibit basic properties such as adhesion. The content of the base polymer in the adhesive sheet 10 is preferably 99.9% by mass or less, more preferably 99.5% by mass or less, and even more preferably 99.0% by mass or less. When the content of the base polymer is at or below the aforementioned upper limit, the content of the metal complex salt black dye can be ensured.

[0057] From the viewpoint of the stability of the coordination bonds in the metal complex salt black dye, the acid value of the base polymer is preferably 30 mg KOH / g or less, more preferably 10 mg KOH / g or less, even more preferably 5.0 mg KOH / g or less, even more preferably 3.0 mg KOH / g or less, even more preferably 1.0 mg KOH / g or less, and particularly preferably 0.0 mg KOH / g. The acid value of the base polymer is, for example, 0.0 mg KOH / g or more. Methods for adjusting the acid value of the base polymer include, for example, adjusting the composition (monomer composition) of the monomer components forming the base polymer. Adjusting the monomer composition includes, for example, adjusting the proportion of carboxyl-containing monomers in the monomer components. The method for determining the acid value of the base polymer is based on JIS K0070:1992, specifically as described in the examples below.

[0058] Metal complex salt black dyes are complex salts of a metal (central metal ion) and a dye compound (ligand). Metal complex salt black dyes can also carry protons. Metal complex salt black dyes can be used as black components with different shades than carbon black (a black with a yellowish tint). However, the lightfastness of the black color of adhesive sheets containing metal complex salt black dyes varies depending on the acid value of the base polymer. The inventors have arrived at this understanding. This invention is based on this understanding.

[0059] Examples of metal complex salt black dyes (central metal ions) include chromium, cobalt, nickel, and copper. From the viewpoint of the stability of metal complex salt black dyes, chromium or copper is preferred. That is, the metal complex salt black dye of the adhesive sheet 10 contains at least one metal (central metal ion of the complex salt) selected from the group consisting of chromium and copper.

[0060] The dye compound (ligand) of the metal complex salt black dye is preferably an azo dye compound, more preferably an aromatic azo dye compound. Furthermore, examples of metal complex salt black dyes include those with a dye compound to metal ratio (quantity ratio) of 1:1 (1:1 type complex salt) and those with a dye compound to metal ratio (quantity ratio) of 2:1 (2:1 type complex salt). From the viewpoint of good color development in the adhesive sheet 10, 2:1 type complex salts are preferred as metal complex salt black dyes. The metal complex salt black dye, which is a 2:1 type complex salt formed from metal M and an aromatic azo dye compound, is shown below with structural formula (1).

[0061]

[0062] In structural formula (1), Ar 1 ~Ar 4Each represents an aromatic ring that can have substituents. Examples of aromatic rings include: benzene rings, naphthalene rings, indene rings, and anthracene rings. Ar is formed. 1 ~Ar 4 The aromatic rings can be all identical to each other, partially identical, or completely different. Examples of substituents include: nitro (-NO2), sulfonic acid (-SO3H), and straight-chain or branched alkyl groups. Examples of alkyl groups include: methyl, ethyl, propyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, isopentyl, neopentyl, n-hexyl, n-heptyl, and 2-ethylhexyl. Furthermore, in structural formula (1), X... 1 ~X 4 Each represents -O- or -COO-. X 1 ~X 4 They can be completely identical, or only partially identical.

[0063] Commercially available metallic complex salt black dyes include, for example: Valifafast Black 3804, 3807, 3808, 3810, 3820, 3830, 3840, 3866, 3870, 3877, and 3878 manufactured by Orient Chemical Industries, Ltd. Other commercially available metallic complex salt black dyes include Orasol Black X45, X51, and X55 manufactured by BASF Japan. Other commercially available metallic complex salt black dyes include Intraplast Black CN manufactured by Sensient. Other commercially available metallic complex salt black dyes include Aizen Spilon Black BH and RLH manufactured by Hodogaya Chemical Industries, Ltd.

[0064] Metal complex salt black dyes can be used alone or in combination with two or more types.

[0065] Metal complex salt black dyes have a blue tint in black, and are therefore preferably selected from at least one of the group consisting of the following structural formulas (2) to (4).

[0066]

[0067] From the viewpoint of suppressing leakage from the adhesive sheet 10, the molecular weight of the metal complex salt black dye is preferably 400 or more, more preferably 500 or more, and even more preferably 600 or more. From the viewpoint of ensuring compatibility with the base polymer, the molecular weight of the metal complex salt black dye is preferably 50,000 or less, more preferably 40,000 or less, even more preferably 30,000 or less, and even more preferably 10,000 or less. From the viewpoint of balancing the above-mentioned leakage suppression and the above-mentioned compatibility assurance, the molecular weight of the metal complex salt black dye is preferably 400 to 50,000, more preferably 500 to 40,000, even more preferably 600 to 30,000, and even more preferably 600 to 10,000. The molecular weight of the metal complex salt black dye is determined based on the structural formula of the metal complex salt black dye.

[0068] From the viewpoint of blackening the adhesive sheet 10, the content of the metal complex salt black dye in the adhesive sheet 10 is preferably 0.01% by mass or more, more preferably 0.05% by mass or more, and even more preferably 0.10% by mass or more. From the viewpoint of ensuring compatibility with the base polymer, the content of the metal complex salt black dye in the adhesive sheet 10 is preferably 10% by mass or less, more preferably 7.0% by mass or less, and even more preferably 5.0% by mass or less. From the viewpoint of balancing the blackening of the adhesive sheet 10 and ensuring the above-mentioned compatibility, the content of the metal complex salt black dye in the adhesive sheet 10 is preferably 0.01% by mass to 10% by mass, more preferably 0.05% by mass to 7.0% by mass, and even more preferably 0.10% by mass to 5.0% by mass. In addition, from the viewpoint of blackening the adhesive sheet 10, the content of the metal complex salt black dye in the adhesive sheet 10 relative to 100 parts by mass of the base polymer is preferably 0.01 parts by mass or more, more preferably 0.05 parts by mass or more, and even more preferably 0.10 parts by mass or more. From the viewpoint of ensuring compatibility with the base polymer, the content of the metal complex salt black dye in the adhesive sheet 10 is preferably 10 parts by mass or less relative to 100 parts by mass of the base polymer, more preferably 7.0 parts by mass or less, and even more preferably 5.0 parts by mass or less.

[0069] The adhesive composition may contain other ingredients as needed. Examples of other ingredients include: silane coupling agents, ultraviolet absorbers, tackifiers, plasticizers, softeners, antioxidants, surfactants, and antistatic agents.

[0070] Examples of UV absorbers include: benzotriazole UV absorbers, hydroxyphenyltriazine UV absorbers, benzophenone UV absorbers, salicylates UV absorbers, cyanoacrylate UV absorbers, and nickel complex salt UV absorbers. UV absorbers can be used alone or in combination of two or more.

[0071] Examples of release liner 21 include, for example, release liners having a release treatment layer on the surface of the liner substrate, and release liners formed of low-adhesion materials. Examples of liner substrates include, for example, resin films and paper. Examples of resins used in resin films include, for example, polyester resins and polycarbonate resins. Examples of polyester resins include, for example, polyethylene terephthalate (PET) and polybutylene terephthalate. The release treatment layer can be formed by surface treatment of the liner substrate using a release treatment agent. Examples of release treatment agents include, for example, polysiloxane release treatment agents, long-chain alkyl release treatment agents, and fluorinated release treatment agents. Examples of low-adhesion materials include, for example, polyolefin resins and fluorinated polymers. Examples of polyolefin resins include, for example, polyethylene, polypropylene, and cyclic olefin polymers (COP). Examples of fluorinated polymers include, for example, polytetrafluoroethylene.

[0072] Examples of release liner 22 include, for instance, release liners having a release treatment layer on the surface of the liner substrate, and release liners formed of low-adhesion materials. Specifically, release liner 22 is the same as described above regarding release liner 21.

[0073] The adhesive composition is prepared by combining a base polymer, a metal complex salt black dye, and other components added as needed. Furthermore, the adhesive sheet 10 can be manufactured using the adhesive composition, for example, by the following operation (first manufacturing method). First, a polymer solution (varnish) is prepared by combining a solvent with the adhesive composition. Examples of solvents include ethyl acetate and toluene. Next, the polymer solution is coated onto a release liner 21 (first release liner) to form a film, and then the film is dried and cured, thereby forming the adhesive sheet 10. Then, the release liner 22 is attached to the adhesive sheet 10 on the release liner 21 as needed. In the first manufacturing method, the metal complex salt black dye is soluble in the polymer solution containing the solvent. Therefore, the metal complex salt black dye is better dispersed in the adhesive sheet 10 compared to pigments (which are insoluble in solvents).

[0074] The adhesive sheet 10 can also be manufactured by, for example, the following method (second manufacturing method).

[0075] First, a prepolymer composition is prepared. Specifically, first, a mixture (liquid state) comprising the aforementioned monofunctional monomers for forming the base polymer and a photopolymerization initiator is prepared (prepolymer composition preparation step). Next, the mixture is irradiated with ultraviolet light, causing a portion of the monofunctional monomers in the mixture to undergo photopolymerization to obtain the prepolymer composition. Examples of light sources for ultraviolet irradiation include ultraviolet LED lamps, black light lamps, high-pressure mercury lamps, and metal halide lamps. During ultraviolet irradiation, the illuminance is, for example, 5 mW / cm². 2m~200mW / cm 2 m, the cumulative irradiation intensity is, for example, 100 mJ / cm. 2 ~5000mJ / cm 2 Ultraviolet irradiation is preferably continued until the viscosity of the composition reaches about 15 Pa·s to about 25 Pa·s. This viscosity was measured using a Type B viscometer under the conditions of rotor No. 5, rotor speed 10 rpm, and temperature 30°C. The prepolymer composition contains a photopolymer of a monofunctional monomer and a monofunctional monomer that has not undergone polymerization (residual monomer). Furthermore, the prepolymer composition does not contain a solvent.

[0076] Next, a multifunctional compound (crosslinking agent), an additional photopolymerization initiator, and other components as needed are added to the prepolymer composition to prepare an adhesive composition (adhesive composition preparation step). Other components may include, for example, oligomers, antioxidants, silane coupling agents, and rust inhibitors. This adhesive composition does not contain solvents. That is, the adhesive composition prepared in this step is a solvent-free adhesive composition.

[0077] Next, as Figure 2 As shown in Figure A, a coating film 10A is formed between release liner 21 and 22' (coating film formation process). Specifically, firstly, an adhesive composition is applied to the release surface of the release liner 21 to form the coating film 10A. Examples of methods for applying the adhesive composition include roller coating, licker coating, gravure coating, reverse coating, roller brush coating, spray coating, dip roller coating, bar coating, doctor blade coating, air knife coating, curtain coating, die lip coating, and die-cutting. Next, the release surface of the release liner 22' is adhered to the coating film 10A on the release liner 21. For example, the same release liner as the release liner 22 can be used as the release liner 22.

[0078] Next, as Figure 2 As shown in Figure B, ultraviolet light is irradiated onto the coating 10A between the release liner 21 and 22' to form a base adhesive sheet 10B (base adhesive sheet formation step). During ultraviolet irradiation, a photopolymerization reaction occurs in the coating within a reaction system containing a monofunctional monomer (residual monomer) and a polyfunctional compound (crosslinking agent) to form a base polymer. This base polymer has a crosslinked structure in which linear units derived from the monofunctional monomer are linked by the polyfunctional compound.

[0079] Next, as Figure 2 As shown in C, the peelable liner 22' will be removed from the base adhesive sheet 10B. Figure 2 B) Peeling (peeling process).

[0080] Next, as Figure 2As shown in Figure D, an additive component is supplied to the base adhesive sheet 10B (the additive component supply process). Specifically, an additive component solution (not shown) containing the additive component and a solvent is applied to the exposed surface of the base adhesive sheet 10B. Examples of solvents include ethyl acetate and toluene. The additive component contains a metal complex salt black dye. Other components may also be included. Examples of other additives include ultraviolet absorbers and antioxidants. In this process, for example, heating is performed as needed while allowing the additive component to penetrate from the surface of the base adhesive sheet 10B into the base adhesive sheet 10B, thereby vaporizing the solvent. The metal complex salt black dye is soluble in the additive component solution containing the solvent. Therefore, in this process, after the metal complex salt black dye in the additive component solution penetrates into the base adhesive sheet 10B as an additive component, it can be well dispersed in the adhesive sheet 10. Furthermore, prior to this process, the base polymer already has a cross-linked structure, thus forming the base adhesive sheet 10B.

[0081] Therefore, through the vaporization of the solvent in this process, the base adhesive sheet 10B is less likely to form (actually does not form) an orange peel-like (yuzuhashi) surface.

[0082] Next, as Figure 2 As shown in E, an additional release liner 22 is bonded to the adhesive sheet 10 (bonding process).

[0083] Through the above operations, it is possible to manufacture an adhesive sheet 10 in which the adhesive surface is covered and protected by release liner 21, 22.

[0084] The adhesive sheet 10 can also be manufactured using the same manufacturing method as the second manufacturing method described above, except for the following (third manufacturing method). In the adhesive composition preparation step, a metal complex salt black dye is added to the solvent-free adhesive composition. Figure 2 In the process shown in B, an adhesive sheet 10 is formed from an adhesive composition (containing a base polymer and a metal complex salt black dye). (Not implemented) Figure 2 C to Figure 2 The processes shown in E. This third manufacturing method also enables the production of adhesive sheets 10 with the adhesive surfaces covered and protected by release liner 21, 22.

[0085] In the second and third manufacturing methods, the adhesive sheet 10 can be manufactured from a solvent-free adhesive composition. Such an adhesive sheet 10 is suitable for reducing environmental impact. That is, the adhesive sheet 10 formed from a solvent-free adhesive composition is preferred from the viewpoint of being environmentally friendly and sustainable.

[0086] From the viewpoint of ensuring sufficient adhesion to the adhered object, the thickness of the adhesive sheet 10 is preferably 10 μm or more, more preferably 15 μm or more, and even more preferably 20 μm or more. From the viewpoint of operability and thinness of the adhesive sheet 10, the thickness of the adhesive sheet 10 is preferably 300 μm or less, more preferably 200 μm or less, even more preferably 100 μm or less, and even more preferably 50 μm or less. From the viewpoint of balancing the above-mentioned adhesion, operability, and thinness, the thickness of the adhesive sheet 10 is preferably 10 μm to 300 μm, more preferably 15 μm to 200 μm, even more preferably 20 μm to 100 μm, and even more preferably 20 μm to 50 μm.

[0087] From the perspective of ensuring the blue tone within the black of adhesive sheet 10, the L of adhesive sheet 10... a b b, the transmitted hue in the color system The value is preferably 0 or less, more preferably -1 or less, and even more preferably -2 or less.

[0088] From the viewpoint of ensuring the transparency required for the adhesive sheet 10 used in the display panel, the haze of the adhesive sheet 10 is preferably 3.0% or less, more preferably 1.0% or less, and even more preferably 0.8% or less. The haze of the adhesive sheet 10 is, for example, 0.0% or more, 0.2% or more, or 0.4% or more. The method for measuring the haze is as described in the embodiments described later.

[0089] As described above, the adhesive sheet 10 contains a metal complex salt black dye as a black component. The dye is soluble in the solution used to form the adhesive sheet 10 during the manufacturing process. Therefore, compared to pigments, the dye is better dispersed in the adhesive sheet 10. Thus, the presence of dye as a black component in the adhesive sheet 10 is suitable for reducing the haze of the adhesive sheet 10.

[0090] Furthermore, in adhesive sheet 10, as described above, the acid value of the base polymer is below 50 mg KOH / g. Acid value refers to the amount (mg) of potassium hydroxide required to neutralize the acidic components contained in 1g of the target material. The lower the acid value of the target material, the less acidic the component. Adhesive sheet 10 containing a base polymer with a low acid value of below 50 mg KOH / g is suitable for ensuring the stability of the coordination bonds between the metal and the dye compound in metal complex salt black dyes (the higher the acid value of the base polymer, the more damaged the coordination bonds). Stabilization of metal complex salt black dyes helps ensure their lightfastness.

[0091] Therefore, adhesive sheet 10 is suitable for ensuring good black lightfastness while suppressing haze.

[0092] The adhesive sheet 10 is, for example, an optical adhesive sheet to be disposed in the light-passing portion of a display panel. Examples of display panels include, for example, liquid crystal display panels and organic EL display panels. The display panel, for example, has a laminated structure including elements such as a pixel panel, a polarizing film, a touch panel, and a protective glass. The adhesive sheet 10 is used, for example, during the manufacturing process of the display panel to bond the elements included in the laminated structure to each other.

[0093] Example

[0094] The following examples illustrate the present invention in detail, but the present invention is not limited to the examples. In addition, the specific values ​​of the amount (content), physical property value, parameters, etc. described below can be replaced with the upper limit (defined as "less than" or "less than") or lower limit (defined as "more than" or "greater than") of the amount (content), physical property value, parameters, etc. corresponding to them described in the above "Specific Embodiments".

[0095] <Preparation of acrylic polymer P1>

[0096] In a reaction vessel equipped with a reflux condenser, a nitrogen inlet pipe, a thermometer, and a stirrer, a mixture comprising 63 parts by mass of 2-ethylhexyl acrylate (2EHA), 9 parts by mass of methyl methacrylate (MMA), 13 parts by mass of 2-hydroxyethyl acrylate (2HEA), 15 parts by mass of N-vinyl-2-pyrrolidone (NVP), 0.2 parts by mass of 2,2'-azobisisobutyronitrile (AIBN) as a polymerization initiator, and 233 parts by mass of ethyl acetate as a solvent was stirred at 60°C under a nitrogen atmosphere for 7 hours (polymerization reaction). This yielded a polymer solution S1 containing an acrylic polymer P1.

[0097] <Preparation of acrylic polymer P2>

[0098] In a reaction vessel equipped with a reflux condenser, a nitrogen inlet pipe, a thermometer, and a stirrer, a mixture containing 99 parts by mass of butyl acrylate (BA), 1 part by mass of 4-hydroxybutyl acrylate (4HBA), 0.2 parts by mass of AIBN as a polymerization initiator, and 155 parts by mass of ethyl acetate as a solvent was stirred at 60°C under a nitrogen atmosphere for 7 hours (polymerization reaction). This yielded a polymer solution S2 containing the acrylic polymer P2.

[0099] <Preparation of acrylic polymer P3>

[0100] In a reaction vessel equipped with a reflux condenser, a nitrogen inlet pipe, a thermometer, and a stirrer, a mixture containing 90 parts by mass of BA, 10 parts by mass of 4HBA, 0.2 parts by mass of AIBN as a polymerization initiator, and 233 parts by mass of ethyl acetate as a solvent was stirred at 60°C under a nitrogen atmosphere for 7 hours (polymerization reaction). This yielded a polymer solution S3 containing acrylic polymer P3.

[0101] <Preparation of acrylic polymer P4>

[0102] In a reaction vessel equipped with a reflux condenser, a nitrogen inlet pipe, a thermometer, and a stirrer, a mixture containing 95 parts by mass of BA, 5 parts by mass of acrylic acid (AA), 0.2 parts by mass of AIBN as a polymerization initiator, and 233 parts by mass of ethyl acetate as a solvent was stirred at 60°C under a nitrogen atmosphere for 7 hours (polymerization reaction). This yielded a polymer solution S4 containing acrylic polymer P4.

[0103] [Example 1]

[0104] <Preparation of Adhesive Compositions>

[0105] In polymer solution S1, relative to 100 parts by mass of acrylic polymer P1, 0.25 parts by mass (converted to solids) of isocyanate crosslinking agent (brand name "TAKENATE D110N", manufactured by Mitsui Chemicals) and 0.16 parts by mass (converted to solids) of a first black dye as the black component (brand name "Valifast Black 3810", 1% ethyl acetate solution, manufactured by Orient Chemical Industries, Ltd.) were added and mixed to prepare an adhesive composition. The first black dye contains: a metal complex salt black dye represented by the above structural formula (2), a metal complex salt black dye represented by the above structural formula (3), and a metal complex salt black dye represented by the above structural formula (4).

[0106] <Making Adhesive Sheets>

[0107] First, an adhesive composition was applied to the release-treated surface of a first release liner (brand name "MRF#38", polyester film, manufactured by Mitsubishi Chemical Corporation) with a thickness of 38 μm and one side having undergone peel treatment, forming a coating film. Next, the coating film was dried by heating at 132°C for 3 minutes. This formed an adhesive layer with a thickness of 25 μm on the first release liner. Then, the release-treated surface of a second release liner (brand name "MRE#38", polyester film, manufactured by Mitsubishi Chemical Corporation) with a thickness of 38 μm and one side having undergone peel treatment was bonded to the adhesive layer on the first release liner. A curing treatment was then performed at 60°C for 24 hours to allow the crosslinking reaction in the adhesive layer to occur. Through the above operations, a black adhesive sheet (25 μm thick) with a release liner was produced as the adhesive sheet of Example 1.

[0108] [Example 2]

[0109] Except for the following, the adhesive sheet with a release liner of Example 2 was made in the same manner as the adhesive sheet of Example 1. In the preparation of the adhesive composition, polymer solution S2 (containing acrylic polymer P2) was used instead of polymer solution S1.

[0110] [Example 3]

[0111] Except for the following, the adhesive sheet with a release liner of Example 3 was made in the same manner as the adhesive sheet of Example 1. In the preparation of the adhesive composition, polymer solution S3 (containing acrylic polymer P3) was used instead of polymer solution S1.

[0112] [Example 4]

[0113] Except for the following, the adhesive sheet with a release liner of Example 4 was prepared in the same manner as the adhesive sheet of Example 1. In the preparation of the adhesive composition, 0.16 parts by weight (converted to solids) of a second black dye (brand name "Valifast Black 3820", 1% MEK solution, manufactured by Orient Chemical Company) was used instead of the first black dye as the black component. The second black dye is a metal complex salt black dye represented by the above structural formula (2).

[0114] [Example 5]

[0115] Except for the following, the adhesive sheet with a release liner of Example 5 was made in the same manner as the adhesive sheet of Example 1. In the preparation of the adhesive composition, polymer solution S2 (containing acrylic polymer P2) was used instead of polymer solution S1, and 0.16 parts by weight (converted to solids amount) of the second black dye (Valifast Black 3820) was used instead of the first black dye as the black component.

[0116] [Example 6]

[0117] Except for the following, the adhesive sheet with a release liner of Example 6 was made in the same manner as the adhesive sheet of Example 1. In the preparation of the adhesive composition, polymer solution S3 (containing acrylic polymer P3) was used instead of polymer solution S1, and 0.16 parts by weight (converted to solids amount) of the second black dye (Valifast Black 3820) was used instead of the first black dye as the black component.

[0118] [Comparative Example 1]

[0119] First, in polymer solution S4, 0.25 parts by weight (converted to solids content) of epoxy crosslinking agent (brand name "Tetrad-c", manufactured by Mitsui Chemicals Co., Ltd.) and 0.16 parts by weight (converted to solids content) of a first black dye (Valifast Black 3810) as the black component were added and mixed relative to 100 parts by weight of acrylic polymer P4 to prepare an adhesive composition. Then, as described above with respect to Example 1, a coating of the adhesive composition was formed on the first release liner, the coating was dried to form an adhesive layer, a second release liner (MRE#38) was bonded onto the adhesive layer, and the adhesive layer was cured. Through the above operations, a black adhesive sheet (25 μm thick) with a release liner was produced as the adhesive sheet of Comparative Example 1.

[0120] [Comparative Example 2]

[0121] Except for the following, an adhesive sheet with a release liner was prepared in Comparative Example 2 in the same manner as the adhesive sheet of Comparative Example 1. In the preparation of the adhesive composition, 0.16 parts by weight (converted to solids amount) of the second black dye (Valifast Black 3820) was used instead of the first black dye as the black component.

[0122] [Comparative Example 3]

[0123] Except for the following, an adhesive sheet with a release liner was prepared in Comparative Example 3 in the same manner as the adhesive sheet of Example 1. In the preparation of the adhesive composition, 0.16 parts by weight (converted to solids) of a third black dye (brand name "OIL BLACK HBB", 1% methyl ethyl ketone solution, manufactured by Orient Chemical Company) was used instead of the first black dye as the black component. The third black dye is not a metal complex salt black dye.

[0124] [Comparative Example 4]

[0125] Except as otherwise provided, an adhesive sheet with a release liner was prepared in Comparative Example 4 in the same manner as the adhesive sheet of Example 1. In the preparation of the adhesive composition, 0.16 parts by weight (converted to solids) of a fourth black dye (brand name "Solvent Violet 13", 1% methyl ethyl ketone solution, manufactured by Taiyo Fine Chemicals) was used instead of the first black dye as the black component. The fourth black dye is not a metal complex salt black dye.

[0126] [Comparative Example 5]

[0127] Except for the following, an adhesive sheet with a release liner was prepared in Comparative Example 5 in the same manner as the adhesive sheet of Example 1. In the preparation of the adhesive composition, carbon black (CB) pigment (brand name "ATDN 101 Black", manufactured by Daihatsu Seika Co., Ltd.) was added in 0.25% by mass in the adhesive layer instead of the first black dye as the black component.

[0128] <Haze, visual transmittance, hue>

[0129] For each adhesive sheet in the embodiments and comparative examples, haze, visual transmittance (Y value) and hue were examined as described below.

[0130] First, a sample for testing is prepared. Specifically, after peeling the second release liner from the adhesive sheet (first release liner / adhesive sheet / second release liner) with the release liner, the exposed adhesive sheet is bonded to an alkali-free glass plate (0.55 mm thick, Eagle glass, manufactured by Matsunami Glass Co., Ltd.). Next, after peeling the first release liner from the adhesive sheet on the alkali-free glass, a polyethylene terephthalate (PET) film (trade name "G 981 E75", 75 μm thick, manufactured by Mitsubishi Chemical Co., Ltd.) is bonded to the exposed adhesive sheet. This yields a laminate containing the adhesive sheet (alkali-free glass / adhesive sheet / PET film). The laminate is then subjected to autoclaving at 50°C, 0.5 MPa, and 15 minutes. This yields the sample for testing.

[0131] Then, for the samples used in the measurement, haze, visual transmittance, and hue were measured using a spectrometer (HSP-150Vis, manufactured by Murakami Color Technology Laboratory Co., Ltd.). value and Value (First Measurement). In this measurement, the sample is placed in the apparatus such that light is irradiated onto the sample from the alkali-free glass side. Furthermore, in this measurement, the measurement result (transmittance spectrum) obtained by measuring the laminated film of the aforementioned alkali-free glass plate (Eagle glass) and PET film (G 981 E75) under the same conditions is used as a baseline. Visual transmittance is specifically: the transmittance (Y value) of transmitted light with wavelengths from 380 nm to 780 nm through the sample in the CIE-XYZ colorimetric system. value and The value is the transmitted light at Hue in the color system , The values ​​are shown in Table 1. Regarding visual transmittance, the Y values ​​(%) before the lightfastness test described later are shown in Table 1.

[0132] <Acid value of acrylic polymers>

[0133] For each of the acrylic polymers P1 to P4, the acid value was determined according to JIS K0070:1992. Specifically, firstly, approximately 2 g of the acrylic polymer (sample) was accurately weighed into a 100 mL container (Eragonal flask) using a precision balance. Next, 10 mL of solvent was added to the container to dissolve the acrylic polymer, thus preparing a first solution. A mixed solvent containing ethanol and diethyl ether in a 1:1 mass ratio was used as the solvent. Then, 1-3 drops of phenolphthalein ethanol solution as an indicator were added to the first solution, and the solution was stirred. This yielded a second solution (the solution for determination). The second solution was then titrated with a 0.1 N potassium hydroxide-ethanol solution. In this titration, the endpoint of neutralization was defined as the occurrence of a light red color (indicator) lasting for more than 30 seconds. Based on the results of this neutralization titration, the acid value of the acrylic polymer was calculated using the following formula. In the calculation formula, B is the volume (mL) of 0.1N potassium hydroxide-ethanol solution used, f is the coefficient of the 0.1N potassium hydroxide-ethanol solution, and 5.611 is the formula weight of potassium hydroxide, 56.11 × 10⁻⁶. -1 S represents the amount of sample (acrylic polymer) collected (g).

[0134] Acid value (mgKOH / g) = (B × f × 5.611) / S

[0135] <Lightfastness Test>

[0136] For each adhesive sheet of the examples and comparative examples, a lightfastness test was performed by the following procedure.

[0137] First, the test sample (alkali-free glass / adhesive sheet / PET film) used in the first test was placed in the chamber of the lightfastness testing apparatus (brand name "Super Xenon Weather Meter SX75", manufactured by Suga Testing Equipment Co., Ltd.). Specifically, the test sample was placed in the chamber with the PET film of the test sample facing the light source (super xenon lamp). Next, the adhesive sheet in the test sample was exposed to light for 168 hours (lightfastness test) using a super xenon lamp (wavelength 300nm~400nm) at 55°C and 55% relative humidity.

[0138] Then, for the samples used in the lightfastness test, the visual transmittance (second measurement) was measured using a spectrometer (HSP-150Vis, manufactured by Murakami Color Technology Research Institute Co., Ltd.). The method and conditions for this measurement were the same as those for the first measurement. The measured visual transmittance is shown as the Y value (%) after the lightfastness test in Table 1. The difference in Y values ​​before and after the lightfastness test, ΔY value (Y value after test - Y value before test), is also shown in Table 1.

[0139] [evaluate]

[0140] The adhesive sheet of Comparative Example 5 contains carbon black (CB) as the black component, with a relatively high haze of 4.5%. The adhesive sheets of Comparative Examples 3 and 4 each contain a black dye compound (not a metal complex salt black dye) as the black component, resulting in large ΔY values ​​(Comparative Example 3: 16.7%, Comparative Example 4: 16.9%). Although the adhesive sheets of Comparative Examples 1 and 2 each contain a metal complex salt black dye as the black component, the acid value of the base polymer is greater than 50 mg KOH / g, resulting in large ΔY values ​​(Comparative Example 1: 15.2%, Comparative Example 2: 14.4%). In other words, the adhesive sheets of Comparative Examples 1 to 4 have low lightfastness.

[0141] In contrast, the adhesive sheets of the embodiments contain a metal complex salt black dye as the black component, and the acid value of the base polymer is 50 mg KOH / g or less. The haze of the adhesive sheets of such embodiments is 1 or less, which is relatively low. Furthermore, the ΔY value of the adhesive sheets of the embodiments is 6.5% or less (Example 5), which is relatively low. That is, the adhesive sheets of the embodiments exhibit higher black lightfastness compared to the adhesive sheets of Comparative Examples 1 to 4.

[0142] Table 1

[0143] It should be noted that the above-described invention is provided as an illustrative embodiment of the present invention, but this is merely illustrative and not a limiting interpretation. Modifications of the invention that will be apparent to those skilled in the art are included within the scope of the claims.

[0144] Industrial practicality

[0145] The adhesive sheet of the present invention can be suitably used, for example, in the manufacture of display panels such as organic EL panels.

[0146] Label Explanation

[0147] 10 Adhesive Sheets

[0148] H Thickness direction

[0149] 11 First page

[0150] 12 Second page

[0151] 21, 22 Peeling off the gasket

Claims

1. An adhesive sheet, wherein, The adhesive sheet contains a base polymer with an acid value of less than 50 mg KOH / g and a metal complex salt black dye.

2. The adhesive sheet according to claim 1, wherein, The metal complex salt black dye contains at least one metal selected from the group consisting of chromium and copper.

3. The adhesive sheet according to claim 1, wherein, The metal complex salt black dye contains azo dye compounds as dye compounds.

4. The adhesive sheet according to claim 3, wherein, The azo dye compound is an aromatic azo dye compound.

5. The adhesive sheet according to claim 1, wherein, The metal complex salt black dye has a molecular weight of over 400.

6. The adhesive sheet according to claim 1, wherein, The adhesive sheet, L a b b, the transmitted hue in the color system Values ​​below 0.

7. The adhesive sheet according to any one of claims 1 to 6, wherein, The haze of the adhesive sheet is below 3.0%.

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