Adhesive sheet and intermediate laminate

Abstract

To provide a pressure-sensitive adhesive sheet of which the pressure-sensitive adhesive layer can be colored by being irradiated with an active ray in an optional timing, and with which the part other than the colored part can be suppressed from being colored by external light, and to provide an intermediate laminate obtained by using the pressure-sensitive adhesive sheet.SOLUTION: A pressure-sensitive adhesive sheet 1 includes a pressure-sensitive adhesive layer 2 composed of a pressure-sensitive adhesive composition of which the visible light transmittance at a wavelength of 550 nm can be lowered by irradiation of an active ray. The pressure-sensitive adhesive composition includes a pressure-sensitive adhesive polymer being a polymer of a monomer component, a compound colored with an acid, and a photoacid generator. The photoacid generator has a maximum absorption wavelength at 300 nm or less in a wavelength range of 250-400 nm.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to an adhesive sheet and an intermediate laminate, and more particularly, to an adhesive sheet and an intermediate laminate obtained using the adhesive sheet.

Background Art

[0002] In recent years, displays equipped with organic EL panels have been known. Since the organic EL panel has a highly reflective electrode layer, external light reflection and background reflection are likely to occur.

[0003] And in order to prevent external light reflection and background reflection, it is known to provide a layer having a function of absorbing light on the reflective surface of the electrode layer.

[0004] As such a layer, a light absorption layer containing a carbon black pigment and a dye has been proposed (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] On the other hand, when the layer having a function of absorbing light is an adhesive layer, transparency may be required from the viewpoint of inspection and the like.

[0007] In such a case, it is considered to include a compound that is colored by an acid and a photoacid generator in the adhesive layer.

[0008] When such an adhesive layer is irradiated with actinic rays, an acid is generated from the photoacid generator, and the compound is colored by the acid.

[0009] That is, in this adhesive layer, by irradiating actinic light at any timing, the adhesive layer can be colored, and thereby, a function of absorbing light can be imparted.

[0010] However, in such an adhesive layer, depending on the purpose and application, there may be cases where parts other than the colored part are desired to remain transparent or where the amount of coloring is desired to be less than that of the colored part.

[0011] In such cases, when parts other than the colored part are exposed to external light, there is a problem that the parts desired to remain transparent are colored, and the amount of coloring of the parts where the amount of coloring is desired to be less than that of the colored part increases.

[0012] An object of the present invention is to provide an adhesive sheet capable of coloring an adhesive layer by irradiating actinic light at any timing and suppressing the coloring of parts other than the colored part by external light, and an intermediate laminate obtained by using the adhesive sheet.

Means for Solving the Problems

[0013] The present invention [1] is an adhesive sheet comprising an adhesive layer made of an adhesive composition capable of reducing the visible light transmittance at a wavelength of 550 nm by irradiation with actinic light, wherein the adhesive composition contains an adhesive polymer which is a polymer of a monomer component, a compound colored by an acid, and a photoacid generator, and the photoacid generator has a maximum absorption wavelength of 300 nm or less in the wavelength range of 250 nm to 400 nm.

[0014] The present invention [2] further includes the adhesive sheet according to [1] above, which is provided with an actinic light absorption layer capable of absorbing the actinic light.

[0015] The present invention [3] includes the adhesive sheet according to [2] above, wherein the actinic light absorption layer has a wavelength region in which the average transmittance of the actinic light is 1% or less in the wavelength range of 300 nm to 400 nm, and the maximum wavelength X (nm) of the wavelength region and the maximum absorption wavelength Y (nm) of the photoacid generator satisfy the following formula (1). X - Y ≧ 100 (1) The present invention [4] includes the pressure - sensitive adhesive sheet according to [2] or [3] above, wherein the average light transmittance in the active light - absorbing layer at wavelengths of 300 nm to 400 nm is 15% or less, and the average light transmittance at wavelengths of 400 nm to 700 nm is 50% or more.

[0016] The present invention [5] includes the pressure - sensitive adhesive sheet according to any one of [2] to [4] above, wherein the active light - absorbing layer is an ultraviolet - absorbing layer capable of absorbing ultraviolet rays.

[0017] The present invention [6] includes an intermediate laminate including an adherend and the pressure - sensitive adhesive sheet according to any one of [1] to [5] above disposed on one surface of the adherend.

[0018] The present invention [7] includes the intermediate laminate according to [6] above, wherein the pressure - sensitive adhesive layer includes a high - light - transmittance portion having a relatively large average light transmittance at wavelengths of 400 to 700 nm and a low - light - transmittance portion having a relatively small average light transmittance at wavelengths of 400 to 700 nm.

Advantages of the Invention

[0019] In the pressure - sensitive adhesive sheet of the present invention, the pressure - sensitive adhesive layer is made of a pressure - sensitive adhesive composition whose visible light transmittance at a wavelength of 550 nm can be reduced by irradiation with active light.

[0020] Therefore, by irradiating the active light at an arbitrary timing, the pressure - sensitive adhesive layer can be colored, and thereby, a function of absorbing light can be imparted.

[0021] Further, in this pressure - sensitive adhesive sheet, the photoacid generator has a maximum absorption wavelength of 300 nm or less in the range of wavelengths of 250 nm to 400 nm.

[0022] Therefore, when it is desired to keep the portion other than the colored portion in the pressure - sensitive adhesive layer transparent or when it is desired to reduce the coloring amount of the portion other than the colored portion compared to the colored portion, it is possible to suppress the portion other than the colored portion from being colored by external light (exceeding 300 nm and 400 nm or less).

[0023] The intermediate laminate of the present invention includes the pressure-sensitive adhesive sheet of the present invention.

[0024] Therefore, in this intermediate laminate, when it is desired to leave the portions other than the colored portion in the pressure-sensitive adhesive layer transparent or to reduce the coloring amount compared to the colored portion, it is possible to suppress the portions other than the colored portion from being colored by external light (exceeding 300 nm and 400 nm or less).

Brief Description of the Drawings

[0025]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

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Figure 8

Figure 9

Figure 10

MODE FOR CARRYING OUT THE INVENTION

[0026] 1. Pressure-sensitive adhesive sheet The pressure-sensitive adhesive sheet 1 has a film shape (including a sheet shape) having a predetermined thickness, extends in a direction orthogonal to the thickness direction (plane direction), and has a flat upper surface and a flat lower surface.

[0027] Specifically, the pressure-sensitive adhesive sheet 1 does not include the active light absorption layer 3 and includes only the pressure-sensitive adhesive layer 2 (first embodiment), or includes the pressure-sensitive adhesive layer 2 and the active light absorption layer 3 (second embodiment).

[0028] Hereinafter, the first embodiment and the second embodiment will be described respectively. 1-1. First embodiment As shown in FIG. 1, in the first embodiment, the pressure-sensitive adhesive sheet 1 includes the pressure-sensitive adhesive layer 2 and does not include the active light absorption layer 3. That is, in the first embodiment, the pressure-sensitive adhesive sheet 1 is composed of the pressure-sensitive adhesive layer 2. 1-1-1. Pressure-sensitive adhesive layer The pressure-sensitive adhesive layer 2 is a pressure-sensitive adhesive layer for adhering the pressure-sensitive adhesive sheet 1 to an adherend 4 (described later).

[0029] The pressure-sensitive adhesive layer 2 has a film shape extending in the plane direction and has a flat upper surface and a flat lower surface.

[0030] The adhesive layer 2 is made of an adhesive composition whose visible light transmittance at a wavelength of 550 nm can be reduced by irradiation with actinic rays.

[0031] Therefore, by irradiating the adhesive layer 2 with actinic rays at an arbitrary timing, the adhesive layer 2 can be colored, and thereby, a function of absorbing light can be imparted.

[0032] Examples of the actinic rays include ultraviolet rays, visible light, infrared rays, X-rays, α-rays, β-rays, and γ-rays. Preferably, ultraviolet rays are mentioned from the viewpoints of the diversity of the equipment used and the ease of handling.

[0033] Also, the ultraviolet rays mean electromagnetic waves in a wavelength range of 1 nm or more and 400 nm or less.

[0034] That is, the adhesive layer 2 is preferably made of an adhesive composition whose visible light transmittance at a wavelength of 550 nm can be reduced by irradiation with ultraviolet rays.

[0035] The adhesive composition contains an adhesive polymer, a compound that is colored by an acid, and a photoacid generator.

[0036] If the adhesive composition contains an adhesive polymer, a compound that is colored by an acid, and a photoacid generator, the visible light transmittance of the adhesive layer 2 at a wavelength of 550 nm can be surely reduced by irradiation with actinic rays (preferably ultraviolet rays).

[0037] The adhesive polymer is blended to impart adhesiveness.

[0038] The adhesive polymer is a polymer of a monomer component (described later), and examples thereof include acrylic polymers, silicone polymers, urethane polymers, and rubber polymers. From the viewpoints of optical transparency, adhesiveness, and control of the storage elastic modulus, preferably, acrylic polymers are mentioned.

[0039] The acrylic polymer is obtained by polymerization of a monomer component containing (meth)acrylic acid alkyl ester as a main component.

[0040] (Meth)acrylic acid alkyl ester is acrylic acid ester and / or methacrylic acid ester, for example, methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, isopropyl (meth)acrylate, butyl (meth)acrylate, isobutyl (meth)acrylate, s-butyl (meth)acrylate, t-butyl (meth)acrylate, pentyl (meth)acrylate, isopentyl (meth)acrylate, neopentyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, octyl (meth)acrylate, isooctyl (meth)acrylate, nonyl (meth)acrylate, isononyl (meth)acrylate, decyl (meth)acrylate, isodecyl (meth)acrylate, undecyl (meth)acrylate, dodecyl (meth)acrylate, isotridecyl (meth)acrylate, tetradecyl (meth)acrylate, isotetradecyl (meth)acrylate, pentadecyl (meth)acrylate, cetyl (meth)acrylate, heptadecyl (meth)acrylate, octadecyl (meth)acrylate, isooctadecyl (meth)acrylate, nonadecyl (meth)acrylate, eicosyl (meth)acrylate, etc., including linear or branched (meth)acrylic acid C1-20 alkyl esters, etc. Preferably, (meth)acrylic acid C4-12 alkyl esters, more preferably, butyl acrylate is mentioned.

[0041] (Meth)acrylic acid alkyl ester can be used alone or in combination of two or more.

[0042] (Meth)acrylic acid alkyl ester compounding ratio is, for example, 50% by mass or more, preferably 60% by mass or more, based on the monomer component, and, for example, 99% by mass or less.

[0043] Moreover, the monomer component preferably contains an acidic vinyl monomer having an anionic group.

[0044] If the monomer component includes an acidic vinyl monomer having an anionic group, it is promoted to dissociate by the strong acid generated from a photoacid generator (described later), resulting in a stronger color and excellent coloring stability.

[0045] Examples of the acidic vinyl monomer having an anionic group include a carboxyl group-containing vinyl monomer, a sulfo group-containing vinyl monomer, a phosphate group-containing vinyl monomer, and the like.

[0046] Examples of the carboxyl group-containing vinyl monomer include (meth)acrylic acid, 2-carboxyethyl (meth)acrylate, carboxypentyl (meth)acrylate, itaconic acid, maleic acid, fumaric acid, crotonic acid, and the like.

[0047] In addition, examples of the carboxyl group-containing vinyl monomer also include acid anhydride group-containing monomers such as maleic anhydride and itaconic anhydride.

[0048] Examples of the sulfo group-containing vinyl monomer include styrene sulfonic acid, allyl sulfonic acid, and the like.

[0049] Examples of the phosphate group-containing vinyl monomer include 2-hydroxyethyl acryloyl phosphate and the like.

[0050] The acidic vinyl monomer having an anionic group is preferably a carboxyl group-containing vinyl monomer, more preferably (meth)acrylic acid, and even more preferably acrylic acid.

[0051] The acidic vinyl monomer having an anionic group can be used alone or in combination of two or more.

[0052] The blending ratio of the acidic vinyl monomer having an anionic group is, for example, 3 parts by mass or more and, for example, 10 parts by mass or less with respect to 100 parts by mass of the alkyl (meth)acrylate, and, for example, 1% by mass or more and, for example, 8% by mass or less with respect to the monomer component.

[0053] Further, the monomer component preferably does not substantially contain a basic vinyl monomer having a lone pair of electrons copolymerizable with the alkyl (meth)acrylate.

[0054] Specifically, the blending ratio of the basic vinyl monomer having a lone pair of electrons is, for example, 3% by mass or less, preferably 1% by mass or less, more preferably 0.5% by mass or less, and particularly preferably 0% by mass or less with respect to the monomer component. In other words, particularly preferably, the monomer component does not contain a basic vinyl monomer having a lone pair of electrons.

[0055] If the monomer component does not substantially contain a basic vinyl monomer having a lone pair of electrons, the generated acid can react with the compound colored by the acid without being trapped, so that the coloring stability can be improved.

[0056] Examples of the basic vinyl monomer having a lone pair of electrons include heterocyclic ring-containing basic vinyl monomers having nitrogen in the heterocyclic ring, such as N-vinylpyrrolidone, methylvinylpyrrolidone, vinylpyridine, vinylpiperidone, vinylpyrimidine, vinylpiperazine, vinylpyrazine, vinylpyrrole, vinylimidazole, vinyloxazole, vinylmorpholine, N-acryloylmorpholine, N-vinylcaprolactam and the like.

[0057] Further, the monomer component may optionally contain a functional group-containing vinyl monomer copolymerizable with the alkyl (meth)acrylate (excluding the above acidic vinyl monomer having an anionic group and the basic vinyl monomer having a lone pair of electrons).

[0058] Examples of the functional group-containing vinyl monomers include hydroxyl group-containing vinyl monomers, cyano group-containing vinyl monomers, glycidyl group-containing vinyl monomers, aromatic vinyl monomers, vinyl ester monomers, vinyl ether monomers and the like.

[0059] Examples of the hydroxyl group-containing vinyl monomers include, for example, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, 8-hydroxyoctyl (meth)acrylate, 10-hydroxydecyl (meth)acrylate, 12-hydroxylauryl (meth)acrylate, 4-(hydroxymethyl)cyclohexyl)methyl (meth)acrylate and the like. Preferably, 2-hydroxyethyl (meth)acrylate is mentioned, and more preferably, 2-hydroxyethyl acrylate is mentioned.

[0060] Examples of the cyano group-containing vinyl monomers include, for example, (meth)acrylonitrile and the like.

[0061] Examples of the glycidyl group-containing vinyl monomers include, for example, glycidyl (meth)acrylate and the like.

[0062] Examples of the aromatic vinyl monomers include, for example, styrene, p-methylstyrene, o-methylstyrene, α-methylstyrene and the like.

[0063] Examples of the vinyl ester monomers include, for example, vinyl acetate, vinyl propionate and the like.

[0064] Examples of the vinyl ether monomers include, for example, methyl vinyl ether and the like.

[0065] The functional group-containing vinyl monomers can be used alone or in combination of two or more. When a crosslinking agent (described later) is blended, from the viewpoint of introducing a crosslinked structure into the polymer, preferably, a hydroxyl group-containing vinyl monomer is mentioned.

[0066] The blending ratio of the functional group-containing vinyl monomer is, for example, 3 parts by mass or more, preferably 5 parts by mass or more, more preferably 15 parts by mass or more, based on 100 parts by mass of the (meth)acrylic acid alkyl ester, and is, for example, 20 parts by mass or less. Also, based on the monomer component, it is, for example, 4% by mass or more, preferably 10% by mass or more, and is, for example, 30% by mass or less, preferably 20% by mass or less.

[0067] And the acrylic polymer is a polymer obtained by polymerizing the above-described monomer component.

[0068] To polymerize the monomer component, for example, the (meth)acrylic acid alkyl ester is blended with an acidic vinyl monomer having an anionic group and a functional group-containing vinyl monomer as necessary to prepare the monomer component, and this is prepared by a known polymerization method such as solution polymerization, bulk polymerization, emulsion polymerization, etc.

[0069] As the polymerization method, preferably, solution polymerization is mentioned.

[0070] In solution polymerization, for example, the monomer component and a polymerization initiator are blended in a known organic solvent to prepare a monomer solution, and then the monomer solution is heated.

[0071] Examples of the polymerization initiator include peroxide-based polymerization initiators and azo-based polymerization initiators.

[0072] Examples of the peroxide-based polymerization initiator include organic peroxides such as peroxycarbonate, ketone peroxide, peroxyketal, hydroperoxide, dialkyl peroxide, diacyl peroxide, and peroxyester.

[0073] Examples of the azo polymerization initiator include azo compounds such as 2,2'-azobisisobutyronitrile, 2,2'-azobis(2-methylbutyronitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), and dimethyl 2,2'-azobisisobutyrate.

[0074] As the polymerization initiator, an azo polymerization initiator is preferable, and 2,2'-azobisisobutyronitrile is more preferable.

[0075] The polymerization initiator can be used alone or in combination of two or more.

[0076] The compounding ratio of the polymerization initiator is, for example, 0.05 parts by mass or more, preferably 0.1 parts by mass or more, and, for example, 1 part by mass or less, preferably 0.5 parts by mass or less, based on 100 parts by mass of the monomer component.

[0077] The heating temperature is, for example, 50°C or higher and 80°C or lower, and the heating time is, for example, 1 hour or longer and 8 hours or shorter.

[0078] Thereby, the monomer component is polymerized to obtain an acrylic polymer solution containing an acrylic polymer.

[0079] The solid content concentration of the acrylic polymer solution is, for example, 20% by mass or more and, for example, 80% by mass or less.

[0080] The weight average molecular weight of the acrylic polymer is, for example, 100,000 or more, preferably 300,000 or more, more preferably 500,000 or more, and, for example, 5,000,000 or less, preferably 3,000,000 or less, more preferably 2,000,000 or less.

[0081] The above weight average molecular weight is a value measured by GPC (gel permeation chromatography) and calculated in terms of polystyrene.

[0082] The glass transition temperature of the pressure-sensitive polymer is, for example, 0 °C or lower, preferably -20 °C or lower, and usually -70 °C or higher.

[0083] If the glass transition temperature of the pressure-sensitive polymer is equal to or lower than the above upper limit, the step-following property is excellent.

[0084] The glass transition temperature is obtained by calculation using the FOX equation.

[0085] The compound that is colored by an acid is a compound that changes from colorless (transparent) to colored by an acid. Examples thereof include leuco dyes, for example, triarylmethane dyes such as p,p’,p”-tris-dimethylaminotriphenylmethane, for example, diphenylmethane dyes such as 4,4-bis-dimethylaminophenylbenzhydryl benzyl ether, for example, fluoran dyes such as 3-diethylamino-6-methyl-7-chlorofluoran, for example, spiropyran dyes such as 3-methylspirodinaphthopyran, for example, rhodamine dyes such as rhodamine-B-anilinolactam, etc. are mentioned, and preferably, leuco dyes are mentioned.

[0086] The compound that is colored by an acid can be used alone or in combination of two or more.

[0087] The compounding ratio of the compound that is colored by an acid is, for example, 0.5 part by mass or more with respect to 100 parts by mass of the pressure-sensitive polymer, and, for example, 5 parts by mass or less, preferably 2 parts by mass or less.

[0088] The photoacid generator is a compound that generates an acid upon irradiation with actinic light.

[0089] Further, the photoacid generator has a maximum absorption wavelength of 300 nm or less, preferably 280 nm or less, more preferably 260 nm or less in the wavelength range of 250 nm to 400 nm.

[0090] By using such a photoacid generator, generation of an acid by external light (exceeding 300 nm and 400 nm or less) can be suppressed.

[0091] As a result, when it is desired to leave the portion other than the colored portion in the adhesive layer 2 transparent, or when it is desired to reduce the coloring amount of the portion other than the colored portion, it is possible to suppress the portion other than the colored portion from being colored by external light (exceeding 300 nm and 400 nm or less).

[0092] Examples of such photoacid generators include onium compounds and the like.

[0093] Examples of the onium compound include onium cations such as iodonium and sulfonium, and Cl - 、Br - 、I - 、ZnCl3 - 、HSO3 - 、BF4 - 、PF6 - 、AsF6 - 、SbF6 - 、CH3SO3 - 、CF3SO3 - 、(C6F5)4B - 、(C4H9)4B - 、C4F9SO3 - 、CH3C6H4SO3 - Salts composed of anions such as these are included.

[0094] Examples of iodonium include bis(4-tert-butylphenyl)iodonium.

[0095] Examples of sulfonium include diphenyl-2,4,6-trimethylphenylsulfonium.

[0096] Specific examples of such photoacid generators include bis(4-tert-butylphenyl)iodonium-p-toluenesulfonate and diphenyl-2,4,6-trimethylphenylsulfonium-p-toluenesulfonate.

[0097] In addition, commercially available products can also be used as the ultraviolet acid generator. For example, SP-056 (maximum absorption wavelength of 250 nm in the range of 250 nm to 400 nm, manufactured by ADEKA Corporation) and the like can be mentioned.

[0098] The photoacid generator can be used alone or in combination of two or more.

[0099] The compounding ratio of the photoacid generator is, for example, 1 part by mass or more with respect to 100 parts by mass of the pressure-sensitive polymer, and is, for example, 20 parts by mass or less, preferably 15 parts by mass or less, more preferably 5 parts by mass or less.

[0100] Then, the pressure-sensitive composition is prepared by blending and mixing the pressure-sensitive polymer (when the pressure-sensitive polymer is prepared by solution polymerization, the polymer solution), the compound that is colored by an acid, and the photoacid generator at the above ratios (when a polymer solution is used as the pressure-sensitive polymer, it is prepared as a solution of the pressure-sensitive composition).

[0101] From the viewpoint of introducing a crosslinked structure into the pressure-sensitive polymer, a crosslinking agent is preferably blended in the pressure-sensitive composition.

[0102] Examples of the crosslinking agent include isocyanate-based crosslinking agents, epoxy-based crosslinking agents, oxazoline-based crosslinking agents, aziridine-based crosslinking agents, carbodiimide-based crosslinking agents, metal chelate-based crosslinking agents, and the like.

[0103] Examples of the isocyanate-based crosslinking agent include aliphatic diisocyanates such as butylene diisocyanate and hexamethylene diisocyanate, alicyclic diisocyanates such as cyclopentylene diisocyanate, cyclohexylene diisocyanate, and isophorone diisocyanate, and aromatic diisocyanates such as 2,4-tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate, and xylylene diisocyanate.

[0104] In addition, as the isocyanate-based crosslinking agent, derivatives of the above isocyanates (for example, isocyanurate-modified products, polyol-modified products, etc.) are also included.

[0105] As the isocyanate-based crosslinking agent, commercially available products can also be used. For example, Coronate L (trimethylolpropane adduct of tolylene diisocyanate, manufactured by Tosoh Corporation), Coronate HL (trimethylolpropane adduct of hexamethylene diisocyanate, manufactured by Tosoh Corporation), Coronate HX (isocyanurate of hexamethylene diisocyanate, manufactured by Tosoh Corporation), Takenate D110N (trimethylolpropane adduct of xylylene diisocyanate, manufactured by Mitsui Chemicals, Inc.), etc. can be mentioned.

[0106] As the isocyanate-based crosslinking agent, preferably, a trimethylolpropane adduct of hexamethylene diisocyanate and a trimethylolpropane adduct of xylylene diisocyanate can be mentioned.

[0107] As the epoxy-based crosslinking agent, for example, diglycidylaniline, 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane, etc. can be mentioned.

[0108] As the epoxy-based crosslinking agent, commercially available products can also be used. For example, Tetrad C (manufactured by Mitsubishi Gas Chemical Company, Inc.), etc. can be mentioned.

[0109] As the epoxy-based crosslinking agent, preferably, 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane can be mentioned.

[0110] As the crosslinking agent, preferably, an isocyanate-based crosslinking agent and an epoxy-based crosslinking agent, more preferably, an epoxy-based crosslinking agent can be mentioned.

[0111] The crosslinking agent can be used alone or in combination of two or more.

[0112] If a crosslinking agent is blended into the adhesive composition, a functional group such as a hydroxyl group in the polymer reacts with the crosslinking agent, and a crosslinked structure is introduced into the polymer.

[0113] The blending ratio of the crosslinking agent is, for example, 0.01 parts by mass or more, preferably 0.1 parts by mass or more, based on 100 parts by mass of the pressure-sensitive adhesive polymer, and, for example, 10 parts by mass or less, preferably 5 parts by mass or less, more preferably 4 parts by mass or less, still more preferably 3 parts by mass or less, and particularly preferably 1 part by mass or less.

[0114] In addition, when a crosslinking agent is blended into the adhesive composition, a crosslinking catalyst can also be blended in order to accelerate the crosslinking reaction.

[0115] Examples of the crosslinking catalyst include metal-based crosslinking catalysts such as tetra-n-butyl titanate, tetra-isopropyl titanate, ferric naphthenate, butyltin oxide, and dioctyltin dilaurate.

[0116] The crosslinking catalyst can be used alone or in combination of two or more.

[0117] The blending ratio of the crosslinking catalyst is, for example, 0.001 parts by mass or more, preferably 0.01 parts by mass or more, based on 100 parts by mass of the pressure-sensitive adhesive polymer, and, for example, 0.05 parts by mass or less.

[0118] In addition, the adhesive composition may contain various additives such as, for example, a silane coupling agent, an adhesion promoter, a plasticizer, a softening agent, an anti-degradant, a filler, a colorant, a surfactant, an antistatic agent, a rust inhibitor, and an ultraviolet absorber and an antioxidant from the viewpoint of stabilization under a fluorescent lamp or natural light, within a range not impairing the effects of the present invention.

[0119] Thereby, an adhesive composition (when a polymer solution is used as the pressure-sensitive adhesive polymer, a solution of the adhesive composition) is obtained.

[0120] The shear storage modulus G' of this pressure-sensitive adhesive composition (solid content) at 20°C to 50°C is, for example, 1.0×10 4 Pa or more, preferably 2.0×10 4 Pa or more, more preferably 4.0×10 4 Pa or more, and also, for example, 1.0×10 6 Pa or less, preferably 5.0×10 5 Pa or less.

[0121] If the above shear storage modulus G' is within the above range, the adhesion is excellent. When the shear storage modulus G' is lower, the step-following property is also excellent.

[0122] The above shear storage modulus G' is measured by dynamic viscoelasticity measurement under the conditions of a frequency of 1 Hz, a temperature increase rate of 5°C / min, and a temperature range of -70°C to 250°C.

[0123] Then, the pressure-sensitive adhesive layer 2 is formed from the pressure-sensitive adhesive composition by the method described later.

[0124] Since the pressure-sensitive adhesive layer 2 is made of a pressure-sensitive adhesive composition, by irradiating with actinic rays (preferably ultraviolet rays), an acid is generated from a photoacid generator, and the acid causes a compound that is colored by the acid to be colored, whereby the pressure-sensitive adhesive layer 2 changes from colorless (transparent) to colored. That is, before irradiation with actinic rays (preferably ultraviolet rays), the pressure-sensitive adhesive layer 2 is colorless (transparent).

[0125] Also, colorless (transparent) means that the average transmittance at wavelengths of 400 nm or more and 700 nm or less is, for example, 60% or more, preferably 70% or more, more preferably 90% or more, and also, for example, 100% or less.

[0126] Also, colored means that the average transmittance at wavelengths of 400 nm or more and 700 nm or less is, for example, 0% or more, and also, for example, less than 60%, preferably 50% or less.

[0127] The thickness of the adhesive layer 2 is, for example, 3 μm or more, preferably 10 μm or more, and, for example, 50 μm or less, preferably 30 μm or less. 1-1-2. Method for manufacturing the adhesive sheet Next, in the first embodiment, a method for manufacturing the adhesive sheet 1 will be described with reference to FIG. 2.

[0128] In this method, the adhesive sheet 1 is manufactured by preparing the adhesive layer 2.

[0129] To prepare the adhesive layer 2, as shown in FIG. 2A, first, a release film 5 is prepared.

[0130] Examples of the release film 5 include flexible plastic films such as polyethylene, polypropylene, polyethylene terephthalate, and polyester film.

[0131] The thickness of the release film 5 is, for example, 3 μm or more, preferably 10 μm or more, and, for example, 200 μm or less, preferably 100 μm or less, more preferably 50 μm or less.

[0132] The release film 5 is preferably subjected to a release treatment with a release agent such as a silicone-based, fluorine-based, long-chain alkyl-based, or fatty acid amide-based release agent, or a release treatment with silica powder.

[0133] Next, the above adhesive composition (solution of the adhesive composition) is applied to one surface of the release film 5, and the solvent is dried and removed if necessary.

[0134] Examples of the application method of the adhesive composition include roll coating, kiss roll coating, gravure coating, reverse coating, roll brush coating, spray coating, dip roll coating, bar coating, knife coating, air knife coating, curtain coating, lip coating, die coating, and the like.

[0135] As drying conditions, the drying temperature is, for example, 50°C or higher, preferably 70°C or higher, more preferably 100°C or higher, and also, for example, 200°C or lower, preferably 180°C or lower, more preferably 150°C or lower. The drying time is, for example, 5 seconds or longer, preferably 10 seconds or longer, and also, for example, 20 minutes or shorter, preferably 15 minutes or shorter, more preferably 10 minutes or shorter.

[0136] Thereby, the adhesive layer 2 is disposed (prepared) on one surface of the release film 5.

[0137] When the pressure-sensitive adhesive composition contains a crosslinking agent, crosslinking is preferably allowed to proceed by aging simultaneously with drying removal or after drying of the solvent (optionally, after laminating the release film 5 on one surface of the adhesive layer 2).

[0138] The aging conditions are appropriately set according to the type of the crosslinking agent. The aging temperature is, for example, 20°C or higher, and also, for example, 160°C or lower, preferably 50°C or lower. The aging time is 1 minute or longer, preferably 12 hours or longer, more preferably 1 day or longer, and also, for example, 7 days or shorter.

[0139] Thereafter, as shown in FIG. 2B, if necessary, the release film 5 disposed on the other surface of the adhesive layer 2 is peeled off.

[0140] Thereby, the adhesive sheet 1 composed of the adhesive layer 2 is obtained. When the release film 5 is not peeled off, an adhesive sheet 1 including the release film 5 (refer to the dotted line in FIG. 2) and the adhesive layer 2 disposed on one surface of the release film 5 is obtained. Further, a release film 5 can be further disposed on one surface of the adhesive layer 2. In such a case, the adhesive sheet 1 includes the release film 5, the adhesive layer 2 disposed on one surface of the release film 5, and the release film 5 disposed on one surface of the adhesive layer 2.

[0141] In such an adhesive sheet 1, the adhesive layer 2 is formed from an adhesive composition containing a photoacid generator having a maximum absorption wavelength of 300 nm or less in the wavelength range of 250 nm to 400 nm.

[0142] Therefore, it is possible to suppress the photoacid generator from generating an acid by external light (exceeding 300 nm and 400 nm or less).

[0143] As a result, when it is desired to leave the portion other than the colored portion in the adhesive layer 2 transparent, or when it is desired to reduce the coloring amount compared to the colored portion, it is possible to suppress the portion other than the colored portion from being colored by external light (exceeding 300 nm and 400 nm or less). 1-2. Second Embodiment As shown in FIG. 3, in the second embodiment, the adhesive sheet 1 includes an adhesive layer 2 and an actinic ray absorbing layer 3. Specifically, the adhesive sheet 1 includes an adhesive layer 2 and an actinic ray absorbing layer 3 disposed on one surface of the adhesive layer 2.

[0144] When the adhesive sheet 1 includes the actinic ray absorbing layer 3, the actinic ray absorbing layer 3 can block external light (exceeding 300 nm and 400 nm or less) irradiated to the adhesive layer 2. As a result, when it is desired to leave the portion other than the colored portion in this adhesive layer 2 transparent, or when it is desired to reduce the coloring amount compared to the colored portion, it is possible to further suppress the portion other than the colored portion from being colored by external light (exceeding 300 nm and 400 nm or less). 1-2-1. Adhesive Layer The adhesive layer 2 is the lower layer of the adhesive sheet 1.

[0145] The adhesive layer 2 is the same as the adhesive layer 2 in the above-described first embodiment and is formed from the above-described adhesive composition. 1-2-2. Actinic Ray Absorbing Layer The actinic ray absorbing layer 3 is disposed on the entire surface of one surface of the adhesive layer 2, and the actinic ray absorbing layer 3 is the upper layer of the adhesive sheet 1.

[0146] The actinic ray absorbing layer 3 has a film shape extending in the plane direction and has a flat plane and a flat lower surface.

[0147] The active light absorption layer 3 is a layer capable of absorbing active light (it has active light absorption properties). )

[0148] Specifically, the average transmittance of the active light of the active light absorption layer 3 is 15% or less, preferably 10% or less, more preferably 9% or less, still more preferably 8% or less, particularly preferably 7% or less, most preferably 3% or less, and further 1% or less.

[0149] If the above average transmittance is below the above upper limit, when it is desired to leave the portion other than the colored portion in the adhesive layer 2 transparent or when it is desired to reduce the coloring amount compared to the colored portion, it is possible to further suppress the coloring of the portion other than the colored portion by external light.

[0150] The method for measuring the average transmittance will be described in detail in the examples described later.

[0151] The active light absorption layer 3 preferably has ultraviolet absorption properties.

[0152] That is, the active light absorption layer 3 is preferably an ultraviolet absorption layer.

[0153] If the active light absorption layer 3 is an ultraviolet absorption layer, there are advantages such as expanding the options for reflection control and the materials that can be used.

[0154] Examples of the ultraviolet absorption layer include a resin film containing an ultraviolet absorber and an adhesive tape containing an ultraviolet absorber. That is, such an ultraviolet absorption layer contains an ultraviolet absorber.

[0155] The materials constituting the resin film are materials that do not have ultraviolet absorptivity unless an ultraviolet absorber is blended, such as cellulose resins such as triacetyl cellulose (TAC), cyclic polyolefin resins such as cycloolefin polymers, such as acrylic resins, phenyl maleimide resins, polycarbonate resins, polyester resins, polyamide resins, polystyrene resins, etc., preferably cellulose resins, more preferably triacetyl cellulose (TAC).

[0156] These materials can be used alone or in combination of two or more.

[0157] Examples of the ultraviolet absorber include benzotriazole-based compounds, hydroxyphenyltriazine-based compounds, benzophenone-based compounds, salicylic acid ester-based compounds, cyanoacrylate-based compounds, nickel complex salt-based compounds, etc.

[0158] The ultraviolet absorber can be used alone or in combination of two or more.

[0159] As the resin film blended with an ultraviolet absorber, commercially available products can also be used, such as KC2UA (TAC film blended with an ultraviolet absorber, manufactured by Konica Minolta), etc.

[0160] Also, as the adhesive tape blended with an ultraviolet absorber, commercially available products can also be used, such as CS9934U (manufactured by Nitto Denko Corporation), etc.

[0161] Also, as the ultraviolet absorption layer, even if an ultraviolet absorber is not blended, a film formed from a material having ultraviolet absorptivity, such as a polyimide film, etc. can also be mentioned.

[0162] As the polyimide film, commercially available products can also be used, such as Kapton 200H (manufactured by Toray DuPont), etc.

[0163] The average transmittance of the ultraviolet absorption layer at wavelengths of 300 nm or more and 400 nm or less is, for example, 15% or less, preferably 10% or less, more preferably 9% or less.

[0164] If the above average transmittance is equal to or less than the above upper limit, when it is desired to keep the portion other than the colored portion in the adhesive layer 2 transparent or when it is desired to reduce the coloring amount compared to the colored portion, it is possible to suppress the portion other than the colored portion from being colored by external light (ultraviolet rays).

[0165] The average transmittance of the active ray absorption layer 3 at wavelengths of 400 nm or more and 700 nm or less is, for example, 50% or more, preferably 70% or more, more preferably 80% or more, still more preferably 90% or more.

[0166] If the above average transmittance is equal to or more than the above lower limit, the active ray absorption layer 3 has excellent transparency.

[0167] Therefore, this adhesive sheet 1 can be suitably used for optical devices and their components that require transparency.

[0168] That is, the active ray absorption layer 3 preferably has ultraviolet absorptivity (the average transmittance at wavelengths of 300 nm or more and 400 nm or less is equal to or less than the above upper limit), and the average transmittance at wavelengths of 400 nm or more and 700 nm or less is equal to or more than the above lower limit.

[0169] Thereby, the active ray absorption layer 3 has excellent ultraviolet absorptivity and excellent transparency.

[0170] More preferably, the active ray absorption layer 3 has a wavelength region in the range of 300 nm to 400 nm where the average transmittance of the active rays is 1% or less, and the maximum wavelength X (nm) of this wavelength region and the maximum absorption wavelength Y (nm) of the above photoacid generator satisfy the following formula (1). X - Y ≧ 100 (1) That is, X and Y are sufficiently separated.

[0171] If the above formula (1) is satisfied, the active light absorption layer 3 can sufficiently block the active light having the maximum absorption wavelength of the photoacid generator. As a result, when it is desired to leave the portion other than the colored portion in the pressure-sensitive adhesive layer 2 transparent, or when it is desired to reduce the coloring amount compared to the colored portion, it is possible to further suppress the portion other than the colored portion from being colored by external light (exceeding 300 nm and 400 nm or less).

[0172] The thickness of the active light absorption layer 3 is the thickness at which the above-described average transmittance can be obtained. For example, it is 10 μm or more, preferably 20 μm or more, and for example, 200 μm or less, preferably 120 μm or less, more preferably 50 μm or less.

[0173] The active light absorption layer 3 may be a single layer or a plurality of layers.

[0174] When the active light absorption layer 3 is a plurality of layers, the same or different types of active light absorption layers 3 are laminated so that the above-described average transmittance and the above-described thickness are within the above-described ranges.

[0175] Further, the active light absorption layer 3 can be surface-treated (for example, hard coat treatment) if necessary. 1-2-3. Method for manufacturing the pressure-sensitive adhesive sheet Next, in the second embodiment, a method for manufacturing the pressure-sensitive adhesive sheet 1 will be described with reference to FIG. 4.

[0176] This method includes a pressure-sensitive adhesive layer preparation step of preparing the pressure-sensitive adhesive layer 2 and an arrangement step of arranging the active light absorption layer 3 on one surface of the pressure-sensitive adhesive layer 2.

[0177] In the pressure-sensitive adhesive layer preparation step, as shown in FIG. 4A, the pressure-sensitive adhesive layer 2 is prepared in the same manner as in the first embodiment described above.

[0178] Next, in the arrangement step, as shown in FIG. 4B, the active light absorption layer 3 is arranged on one surface of the pressure-sensitive adhesive layer 2.

[0179] Thereafter, if necessary, the release film 5 disposed on the other surface of the adhesive layer 2 is peeled off.

[0180] Thereby, an adhesive sheet 1 including the adhesive layer 2 and the active ray absorbing layer 3 disposed on one surface of the adhesive layer 2 is obtained. When the release film 5 is not peeled off, an adhesive sheet 1 including the release film 5 (refer to the dotted line in FIG. 4B), the adhesive layer 2 disposed on one surface of the release film 5, and the active ray absorbing layer 3 disposed on one surface of the adhesive layer 2 is obtained.

[0181] In the above description, the adhesive sheet 1 is composed of the adhesive layer 2 and the active ray absorbing layer 3, but an intermediate layer such as a transparent substrate made of a flexible plastic material can also be interposed between the adhesive layer 2 and the active ray absorbing layer 3.

[0182] In such an adhesive sheet 1, the adhesive layer 2 is formed from an adhesive composition containing a photoacid generator having a maximum absorption wavelength of 300 nm or less in the wavelength range of 250 nm to 400 nm.

[0183] Therefore, it is possible to suppress the photoacid generator from generating an acid by external light (exceeding 300 nm and 400 nm or less).

[0184] As a result, when it is desired to leave the portion other than the colored portion in the adhesive layer 2 transparent or to reduce the coloring amount compared to the colored portion, it is possible to suppress the portion other than the colored portion from being colored by external light (exceeding 300 nm and 400 nm or less).

[0185] Further, such an adhesive sheet 1 includes an active ray absorbing layer 3. Therefore, the active ray absorbing layer 3 can block external light (exceeding 300 nm and 400 nm or less) irradiated to the adhesive layer 2. As a result, when it is desired to leave the portion other than the colored portion in the adhesive layer 2 transparent or to reduce the coloring amount compared to the colored portion, it is possible to further suppress the portion other than the colored portion from being colored by external light (exceeding 300 nm and 400 nm or less). 2. Intermediate laminate Next, the intermediate laminate 6 obtained using the above-described adhesive sheet 1 will be described.

[0186] The intermediate laminate 6 has a film shape (including a sheet shape) having a predetermined thickness, extends in a direction orthogonal to the thickness direction (plane direction), and has a flat upper surface and a flat lower surface.

[0187] Specifically, the intermediate laminate 6 includes an adherend 4 and an adhesive sheet 1 disposed on one surface of the adherend 4.

[0188] More specifically, when the intermediate laminate 6 is obtained using the adhesive sheet 1 of the first embodiment, as shown in FIG. 5, the intermediate laminate 6 includes an adherend 4 and an adhesive layer 2 disposed on one surface of the adherend 4. Further, in this intermediate laminate 6, if necessary, a release film 5 can be disposed on one surface of the adhesive layer 2. In such a case, the intermediate laminate 6 includes an adherend 4, an adhesive layer 2 disposed on one surface of the adherend 4, and a release film 5 disposed on one surface of the adhesive layer 2 (see the dotted line in FIG. 5).

[0189] Further, when the intermediate laminate 6 is obtained using the adhesive sheet 1 of the second embodiment, as shown in FIG. 6, the intermediate laminate 6 includes an adherend 4, an adhesive layer 2 disposed on one surface of the adherend 4, and an active ray absorption layer 3 disposed on one surface of the adhesive layer 2.

[0190] On the other hand, in the above-described intermediate laminate 6, the adhesive layer 2 is not pre-colored. However, as will be described in detail later, in the intermediate laminate 6, a part of the adhesive layer 2 can be pre-colored.

[0191] In such a case, as shown in FIGS. 7 (when the adhesive sheet 1 of the first embodiment is used) and 8 (when the adhesive sheet 1 of the second embodiment is used), respectively, the adhesive layer 2 in the intermediate laminate 6 includes a high light transmittance portion 10 having a relatively large average light transmittance at wavelengths of 400 to 700 nm and a low light transmittance portion 11 having a relatively small average light transmittance at wavelengths of 400 to 700 nm.

[0192] Further, as will be described in detail later, the intermediate laminate 6 is obtained by attaching the above-described adhesive sheet 1 to the adherend 4.

[0193] In the following description, the intermediate laminate 6 obtained by using the adhesive sheet 1 of the first embodiment will be described. 2-1. Adherend The adherend 4 is a body to be reinforced by the adhesive sheet 1, and examples thereof include optical devices, electronic devices, and their components.

[0194] In FIGS. 5 and 6, the adherend 4 has a flat plate shape, but the shape of the adherend 4 is not particularly limited, and various shapes are selected depending on the types of optical devices, electronic devices, and their structural components. 2-2. Manufacturing method of intermediate laminate As described above, the adhesive layer 2 in the intermediate laminate 6 does not have to be pre-colored, or a part of the adhesive layer 2 may be pre-colored.

[0195] Therefore, the manufacturing method of the intermediate laminate 6 when the adhesive layer 2 is not pre-colored and the manufacturing method of the intermediate laminate 6 when a part of the adhesive layer 2 is pre-colored will be separately described below. 2-2-1. Manufacturing method of intermediate laminate when adhesive layer is not pre-colored The manufacturing method of the intermediate laminate 6 when the adhesive layer 2 is not pre-colored will be described with reference to FIG. 9.

[0196] The manufacturing method of the intermediate laminate 6 includes a preparation step of preparing the above-described adhesive sheet 1 and an attachment step of disposing (attaching) the adherend 4 on the other surface of the adhesive sheet 1.

[0197] In the preparation step, as shown in FIG. 9A, the adhesive sheet 1 is prepared.

[0198] Specifically, an adhesive sheet 1 including a release film 5, an adhesive layer 2 disposed on one surface of the release film 5, and a release film 5 disposed on one surface of the adhesive layer 2 is prepared.

[0199] In the pasting step, the adherend 4 is placed (pasted) on the other side of the adhesive sheet 1.

[0200] Specifically, as shown in FIG. 9B, the release film 5 disposed on the other side of the adhesive sheet 1 (the other side of the adhesive layer 2) is peeled off, and the adherend 4 is placed (pasted) on the other side of the adhesive sheet 1 (the other side of the adhesive layer 2).

[0201] Thereafter, if necessary, the release film 5 disposed on one side of the adhesive layer 2 is peeled off.

[0202] Thereby, an intermediate laminate 6 including the adherend 4 and the adhesive sheet 1 (adhesive layer 2) disposed on one side of the adherend 4 is obtained. Also, when the release film 5 is not peeled off, an intermediate laminate 6 including the adherend 4, the adhesive layer 2 disposed on one side of the adherend 4, and the release film 5 disposed on one side of the adhesive layer 2 (see the dotted line in FIG. 9B) is obtained.

[0203] Since this intermediate laminate 6 includes the above-mentioned adhesive sheet 1, when it is desired to leave the portion other than the colored portion in the adhesive layer 2 transparent or when it is desired to reduce the coloring amount compared to the colored portion, it is possible to suppress the portion other than the colored portion from being colored by external light (exceeding 300 nm and 400 nm or less). 2-2-2. Manufacturing method of intermediate laminate when a part of the adhesive layer is pre-colored The manufacturing method of the intermediate laminate 6 when a part of the adhesive layer 2 is pre-colored will be described with reference to FIG. 10.

[0204] The manufacturing method of the intermediate laminate 6 includes a preparation step of preparing the above-mentioned adhesive sheet 1, an irradiation step of irradiating a part of the adhesive layer 2 with actinic rays (preferably ultraviolet rays), and a pasting step of placing (pasting) the adherend 4 on the other side of the adhesive sheet 1.

[0205] In the preparation step, as shown in FIG. 10A, the adhesive sheet 1 is prepared.

[0206] Specifically, an adhesive sheet 1 is prepared, which includes a release film 5, an adhesive layer 2 disposed on one surface of the release film 5, and a release film 5 disposed on one surface of the adhesive layer 2.

[0207] In the irradiation step, as shown in FIG. 10B, a part of the adhesive layer 2 is irradiated with actinic rays (preferably, ultraviolet rays) to form an irradiated portion 20 where the irradiation amount of the actinic rays (preferably, ultraviolet rays) is relatively high and a non-irradiated portion 21 where the actinic rays (preferably, ultraviolet rays) are not irradiated in the adhesive layer 2.

[0208] In the following description, the adhesive sheet 1 is irradiated with actinic rays (preferably, ultraviolet rays) at two locations at both ends of the adhesive sheet 1 divided into three parts in the plane direction, and a part of the adhesive sheet 1 (adhesive layer 2) irradiated with the actinic rays (preferably, ultraviolet rays) is used as the irradiated portion 20 (in other words, only one part in the middle of the adhesive sheet 1 divided into three parts in the plane direction is the non-irradiated portion 21) for explanation.

[0209] Specifically, in the irradiation step, in the adhesive sheet 1, the irradiated portion 20 is irradiated with actinic rays (preferably, ultraviolet rays) from the surface side of the release film 5 on one side, and the non-irradiated portion 21 is not irradiated with actinic rays (preferably, ultraviolet rays).

[0210] Specifically, a mask 7 that blocks actinic rays (preferably, ultraviolet rays) is not disposed on the irradiated portion 20 (specifically, one surface of the release film 5 disposed on one surface of the irradiated portion 20), and a mask 7 that blocks actinic rays (preferably, ultraviolet rays) is disposed on the non-irradiated portion 21 (specifically, one surface of the release film 5 disposed on one surface of the non-irradiated portion 21), and then the actinic rays (preferably, ultraviolet rays) are irradiated.

[0211] As a result, only the irradiated portion 20 is irradiated with actinic rays (preferably, ultraviolet rays).

[0212] In the adhesive layer 2 in the irradiation portion 20, an acid is generated from the photoacid generator, and the acid causes a compound that is colored by the acid to be colored (specifically, black). As a result, the adhesive layer 2 in the irradiation portion 20 changes from colorless (transparent) to colored (the average light transmittance at wavelengths of 400 to 700 nm decreases). Then, the average light transmittance at wavelengths of 400 to 700 nm in the irradiation portion 20 becomes smaller than the average light transmittance at wavelengths of 400 to 700 nm in the non-irradiation portion 21 (specifically, the irradiation portion 20 becomes blacker than the non-irradiation portion 21).

[0213] That is, a relatively low average light transmittance irradiation portion 20 at wavelengths of 400 to 700 nm and a relatively high average light transmittance non-irradiation portion 21 at wavelengths of 400 to 700 nm are formed.

[0214] Then, the irradiation portion 20 becomes the low light transmittance portion 11, and the non-irradiation portion 21 becomes the high light transmittance portion 10.

[0215] In the pasting step, the adherend 4 is placed (pasted) on the other surface of the adhesive sheet 1.

[0216] Specifically, as shown in FIG. 10C, the release film 5 disposed on the other surface of the adhesive sheet 1 (the other surface of the adhesive layer 2) is peeled off, and the adherend 4 is placed (pasted) on the other surface of the adhesive sheet 1 (the other surface of the adhesive layer 2).

[0217] After that, if necessary, the release film 5 disposed on one surface of the adhesive layer 2 is peeled off.

[0218] Thereby, an intermediate laminate 6 including the adherend 4 and the adhesive sheet 1 (adhesive layer 2) disposed on one surface of the adherend 4 is obtained. When the release film 5 is not peeled off, an intermediate laminate 6 including the adherend 4, the adhesive layer 2 disposed on one surface of the adherend 4, and the release film 5 disposed on one surface of the adhesive layer 2 (refer to the dotted line in FIG. 10C) is obtained.

[0219] Since this intermediate laminate 6 includes the above-described adhesive sheet 1, when it is desired to leave the portions other than the colored portions in the adhesive layer 2 transparent, it is possible to suppress the portions other than the colored portions from being colored by external light.

[0220] Further, in such an intermediate laminate 6, the adhesive layer 2 includes a high light transmittance portion 10 having a relatively large average light transmittance at wavelengths of 400 to 700 nm and a low light transmittance portion 11 having a relatively small average light transmittance at wavelengths of 400 to 700 nm.

[0221] In the above description, the sticking step is carried out after the irradiation step, but the irradiation step can also be carried out after the sticking step.

[0222] In the above description, the manufacturing method of the intermediate laminate 6 using the adhesive sheet 1 of the first embodiment has been described. However, even when using the adhesive sheet 1 of the second embodiment, the intermediate laminate 6 can be manufactured by the same procedure as above.

[0223] In the above description, the irradiated portion 20 is the low light transmittance portion 11 and the non-irradiated portion 21 is the high light transmittance portion 10. However, by forming a high irradiation portion with a large amount of actinic ray irradiation and a low irradiation portion with a small amount of actinic ray irradiation, the high irradiation portion can be the low light transmittance portion 11 and the low irradiation portion can be the high light transmittance portion 10.

Examples

[0224] Examples and comparative examples are shown below to more specifically explain the present invention. Note that the present invention is not limited to any examples and comparative examples. Further, specific numerical values such as the blending ratio (content ratio), physical property values, parameters, etc. used in the following description can be replaced with the upper limit values (numerical values defined as "hereinafter", "less than") or lower limit values (numerical values defined as "above", "exceeding") of the corresponding blending ratio (content ratio), physical property values, parameters, etc. described in the above "Mode for Carrying Out the Invention". Note that "parts" and "%" are based on mass unless otherwise specified.

[0225] 1. Details of Components The components used in each example and each comparative example are described below. BA: Butyl acrylate AA: Acrylic acid Tetrad C: Trade name: 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane (epoxy crosslinking agent), manufactured by Mitsubishi Gas Chemical BLACK ND1: Leuco dye, manufactured by Yamada Chemical Industry SP-056: Photoacid generator, maximum absorption wavelength 250 nm in the range of 250 nm to 400 nm, manufactured by ADEKA Bis(4-tert-butylphenyl)iodonium p-toluenesulfonate: Photoacid generator, maximum absorption wavelength 250 nm in the range of 250 nm to 400 nm Diphenyl-2,4,6-trimethylphenylsulfonium p-toluenesulfonate: Photoacid generator, maximum absorption wavelength 257 nm in the range of 250 nm to 400 nm SP-606: Photoacid generator, maximum absorption wavelength 343 nm in the range of 250 nm to 400 nm, manufactured by ADEKA KC2UA: TAC film containing an ultraviolet absorber, thickness 25 μm, manufactured by Konica Minolta Inc. UVA-TAC: Film comprising KC2UA and a hard coat layer in this order (obtained by forming a hard coat layer (thickness: 7 μm) on one surface of KC2UA (thickness: 25 μm) by hard coat treatment), thickness 32 μm UVA-OCA: Adhesive tape having an ultraviolet absorption function, trade name "CS9934U", thickness 100 μm, manufactured by Nitto Denko Corporation

[0226] 2. Preparation of Adhesive Polymer Synthesis Example 1 Into a reaction vessel equipped with a thermometer, a stirrer, a reflux condenser tube, and a nitrogen gas inlet tube, 95 parts by mass of butyl acrylate (BA), 5 parts by mass of acrylic acid (AA) as monomer components, 0.2 parts by mass of azobisisobutyronitrile as a polymerization initiator, and 233 parts by mass of ethyl acetate as a solvent were charged. Nitrogen gas was passed through, and nitrogen substitution was carried out for about 1 hour while stirring. Then, it was heated to 60 °C and reacted for 7 hours to obtain a solution of a tacky polymer having a weight average molecular weight (Mw) of 600,000.

[0227] 3. Production of the pressure-sensitive adhesive sheet Comparison Example 2 To the solution of the tacky polymer of Synthesis Example 1, 0.075 part by mass of Tetrad C as a crosslinking agent, 1 part by mass of BLACK ND1 (leuco dye) as a compound colored by an acid, and 2 parts by mass of SP-056 as a photoacid generator were added per 100 parts by mass of the tacky polymer in the solution of the tacky polymer, and they were uniformly mixed to prepare a pressure-sensitive adhesive composition.

[0228] Next, on one side of a 50-μm-thick polyethylene terephthalate film (hereinafter referred to as Release Film A) that has been surface release-treated, the pressure-sensitive adhesive composition of Synthesis Example 1 was applied with a fountain roll so that the thickness after drying would be 25 μm, and it was dried at 130 °C for 1 minute to remove the solvent. Thereby, a pressure-sensitive adhesive layer provided with Release Film A on the other side was formed. Further, on one side of the pressure-sensitive adhesive layer, the release-treated surface of Release Film B (a 25-μm-thick polyethylene terephthalate film whose surface has been silicone release-treated) was laminated. Then, aging treatment was carried out in an atmosphere of 25 °C for 4 days to allow the crosslinking reaction to proceed. Thereby, the pressure-sensitive adhesive layer was produced (prepared).

[0229] Next, the Release Film B disposed on one side of the pressure-sensitive adhesive layer was peeled off, and a glass substrate, a low-adhesion layer made of a known adhesive, a PET film, a high-adhesion layer made of a known adhesive, and a PET film were sequentially arranged on one side of the pressure-sensitive adhesive layer.

[0230] Note that the low-adhesion layer has an adhesion force that allows the glass substrate and the PET film to be peeled off.

[0231] In addition, the average transmittance of ultraviolet rays through the low-adhesion layer and the high-adhesion layer is 50% or more.

[0232] As a result, a test intermediate laminate including a release film A, an adhesive layer, a glass substrate, a low-adhesion layer, a PET film, a high-adhesion layer, and a PET film (specifically, a test intermediate laminate without an active light absorption layer) was obtained.

[0233] Example 2 Comparison Example 2 After preparing an adhesive layer in the same procedure as in Example, the release film B disposed on one surface of the adhesive layer was peeled off, and a glass substrate, a low-adhesion layer made of a known adhesive, a PET film, a high-adhesion layer made of a known adhesive, and UVA-TAC as an active light absorption layer were sequentially disposed on one surface of the adhesive layer.

[0234] As a result, a test intermediate laminate including a release film A, an adhesive layer, a glass substrate, a low-adhesion layer, a PET film, a high-adhesion layer, and an active light absorption layer (specifically, a test intermediate laminate with an active light absorption layer) was obtained.

[0235] Example 3 A test intermediate laminate (specifically, a test intermediate laminate with an active light absorption layer) was manufactured in the same manner as in Example 2, except that UVA-OCA was used as the active light absorption layer.

[0236] Example 4 A test intermediate laminate (specifically, a test intermediate laminate with an active light absorption layer) was manufactured in the same manner as in Example 2, except that UVA-TAC and UVA-OCA were used as the active light absorption layer (specifically, UVA-TAC was disposed on one surface of the high-adhesion layer, and UVA-OCA was disposed on one surface of UVA-TAC).

[0237] ComparisonExample 3 Except for changing to the pressure-sensitive adhesive composition shown below, Comparison Example 2 In the same procedure as , a test intermediate laminate (specifically, a test intermediate laminate without an active ray absorbing layer) was produced. (Pressure-sensitive adhesive composition) To a solution of the pressure-sensitive adhesive polymer of Synthesis Example 1, as a crosslinking agent, Tetrad C was added in an amount of 0.075 parts by mass based on 100 parts by mass of the pressure-sensitive adhesive polymer in the solution of the pressure-sensitive adhesive polymer, and as a compound that is colored by an acid, BLACK ND1 (leuco dye) was added in an amount of 1 part by mass based on 100 parts by mass of the pressure-sensitive adhesive polymer in the solution of the pressure-sensitive adhesive polymer, and as a photoacid generator, bis(4-tert-butylphenyl)iodonium p-toluenesulfonate was added in an amount of 2 parts by mass based on 100 parts by mass of the pressure-sensitive adhesive polymer in the solution of the pressure-sensitive adhesive polymer, and they were uniformly mixed to prepare a pressure-sensitive adhesive composition. per 100 parts by mass of the pressure-sensitive adhesive polymer in the solution of the pressure-sensitive adhesive polymer, and a photoacid generator, bis(4-tert-butylphenyl)iodonium p-toluenesulfonate, was added in an amount of 2 parts by mass per 100 parts by mass of the pressure-sensitive adhesive polymer in the solution of the pressure-sensitive adhesive polymer, and they were uniformly mixed to prepare a pressure-sensitive adhesive composition. olymer, and as a compound that is colored by an acid, BLACK ND1 (leuco dye) was added in an amount of 1 part by mass per 100 parts by mass of the pressure-sensitive adhesive polymer in the solution of the pressure-sensitive adhesive polymer, and as a photoacid generator, bis(4-tert-butylphenyl)iodonium p-toluenesulfonate was added in an amount of 2 parts by mass per 100 parts by mass of the pressure-sensitive adhesive polymer in the solution of the pressure-sensitive adhesive polymer, and they were uniformly mixed to prepare a pressure-sensitive adhesive composition. per 100 parts by mass of the pressure-sensitive adhesive polymer in the solution of the pressure-sensitive adhesive polymer, and they were uniformly mixed to prepare a pressure-sensitive adhesive composition.

[0238] Comparison Example 4 Except for changing to the pressure-sensitive adhesive composition shown below, Comparison Example 2 In the same procedure as , a test intermediate laminate (specifically, a test intermediate laminate without an active ray absorbing layer) was produced. (Pressure-sensitive adhesive composition) To a solution of the pressure-sensitive adhesive polymer of Synthesis Example 1, as a crosslinking agent, Tetrad C was added in an amount of 0.075 parts by mass based on 100 parts by mass of the pressure-sensitive adhesive polymer in the solution of the pressure-sensitive adhesive polymer, and as a compound that is colored by an acid, BLACK ND1 (leuco dye) was added in an amount of 1 part by mass based on 100 parts by mass of the pressure-sensitive adhesive polymer in the solution of the pressure-sensitive adhesive polymer, and as a photoacid generator, diphenyl-2,4,6-trimethylphenylsulfonium p-toluenesulfonate was added in an amount of 2 parts by mass based on 100 parts by mass of the pressure-sensitive adhesive polymer in the solution of the pressure-sensitive adhesive polymer, and they were uniformly mixed to prepare a pressure-sensitive adhesive composition.

[0239] Example 7 Comparison Example 3In the same manner as described above, an adhesive layer was prepared, and a test intermediate laminate (specifically, a test intermediate laminate including an active ray absorbing layer) was produced in the same manner as in Example 2, except that UVA-OCA was used as the active ray absorbing layer.

[0240] Example 8 Comparison Example 4 In the same manner as described above, an adhesive was prepared, and a test intermediate laminate (specifically, a test intermediate laminate including an active ray absorbing layer) was produced in the same manner as in Example 2, except that UVA-OCA was used as the active ray absorbing layer.

[0241] Comparative Example 1 Except that SP-606 was used as the photoacid generator, Comparison Example 2 In the same manner as described above, a test intermediate laminate (specifically, a test intermediate laminate not including an active ray absorbing layer) was produced.

[0242] As described above, Ratio Comparative Example 1 to Comparative Example 4 is a test intermediate laminate not including an active ray absorbing layer, and Examples 2 to 4, Example 7, and Example 8 are test intermediate laminates including an active ray absorbing layer.

[0243] In other words, Ratio Comparative Example 1 to Comparative Example 4 is a laminate in which the active ray absorbing layer in Examples 2 to 4, Example 7, and Example 8 is replaced with a PET film.

[0244] 4. Evaluation (Measurement of the maximum absorption wavelength Y of the photoacid generator in the range of 250 nm to 400 nm) Each photoacid generator was dissolved in THF, and after preparing a 0.01 mass% THF solution, this THF photoacid generator solution was added to a quartz cell, and the absorption wavelength was measured using a V750 manufactured by JASCO Corporation. Note that only THF was used for the baseline. (Average transmittance of the adhesive layer before LED irradiation) Ratio Comparative Example 1 to Comparative Example 4The release film B disposed on one surface of the adhesive layer was peeled off, and one surface of the adhesive layer was adhered to the glass substrate.

[0245] Thereafter, the release film A disposed on the other surface of the adhesive layer was peeled off. Thus, a sample for measuring the average transmittance was prepared.

[0246] This sample for measuring the average transmittance was installed in a transmittance measuring device (U4100 type spectrophotometer, manufactured by Nippon High-Techno Co., Ltd.) such that the adhesive layer was disposed on the light source side, and the average transmittance at wavelengths from 400 nm to 700 nm was measured.

[0247] Note that the data measured with only the glass substrate was used as the baseline.

[0248] The results are shown in Table 1.

[0249] (Average transmittance of the adhesive layer after LED irradiation) After irradiating the adhesive layer in the above sample for measuring the average transmittance with light from an LED (365 nm, 8000 mJ / □), the average transmittance at wavelengths from 400 nm to 700 nm was measured in the same manner as above.

[0250] Separately, after irradiating the adhesive layer in the above sample for measuring the average transmittance with light from an LED (365 nm, 16000 mJ / □), the average transmittance at wavelengths from 400 nm to 700 nm was measured in the same manner as above.

[0251] Also, the change rate before and after LED irradiation was determined by the following formula (2). Change rate before and after LED irradiation = (Average transmittance before LED irradiation - Average transmittance after LED irradiation) / (Average transmittance before LED irradiation) (2) The results are shown in Table 1.

[0252] (Average transmittance of the active ray absorbing layer) Each active light absorption layer was placed in a transmittance measuring device (U4100 spectrophotometer, manufactured by Nippon High-Techno Co., Ltd.), and the average transmittance at wavelengths from 300 nm to 400 nm and the average transmittance at wavelengths from 400 nm to 700 nm were measured.

[0253] Note that the data measured with nothing placed in the measuring device was used as the baseline.

[0254] The results are shown in Table 2.

[0255] In addition, in Table 2, for each active light absorption layer, the maximum wavelength X (nm) of the wavelength region where the average transmittance of the active light is 1% or less within the range of wavelengths from 300 nm to 400 nm is also noted.

[0256] (External light stability) On one side of the test intermediate laminate of each example and each comparative example ( Comparison Example 2 and in Comparative Example 1, on the PET film side of one side, in Examples 2 to 4, Example 7, and Example 8, on the active light absorption layer side), the test intermediate laminates of each example and each comparative example were left to stand so that sunlight was irradiated.

[0257] Then, the average transmittance at wavelengths from 400 nm to 700 nm at the start of leaving to stand and 2 weeks after the start of leaving to stand was measured.

[0258] Specifically, Comparison Example 2 and in Comparative Example 1, the low adhesion layer disposed on one surface of the glass substrate, the PET film, the high adhesion layer, and the PET film were peeled off, and the release film A disposed on the other surface of the adhesion layer was peeled off. Also, in Examples 2 to 4, Example 7, and Example 8, the low adhesion layer disposed on one surface of the glass substrate, the PET film, the high adhesion layer, and the ultraviolet absorption layer were peeled off from the adhesion layer, and the release film A disposed on the other surface of the adhesion layer was peeled off.

[0259] Thereby, a sample for measuring external light stability having an adhesive layer and a glass substrate in this order was prepared.

[0260] Then, this sample for measuring external light stability was installed in a transmittance measuring device (U4100 type spectrophotometer, manufactured by Nippon High-Techno Co., Ltd.) so that the adhesive layer was disposed on the light source side, and the average transmittance at wavelengths of 400 nm to 700 nm was measured.

[0261] Note that the data measured with only the glass substrate was used as the baseline.

[0262] In addition, the change rate after each lapse of time was determined by the following formula (3). Change rate after each lapse of time = (Average transmittance at the start of standing - Average transmittance after each lapse of time) / (Average transmittance at the start of standing) (3) The results are shown in Table 2.

[0263] 5. Discussion In the evaluation of the average transmittance, the adhesive layer is composed of an adhesive composition capable of reducing the visible light transmittance at a wavelength of 550 nm by irradiation with ultraviolet rays Comparison Example 2 to Comparison Example 4 The average transmittance at wavelengths of 400 nm to 700 nm before and after irradiating the adhesive sheet with an LED has decreased.

[0264] From this, it can be seen that when using the adhesive sheet provided with the above adhesive layer, the adhesive layer can be colored by irradiating ultraviolet rays at an arbitrary timing.

[0265] In addition, in the evaluation of the average transmittance, the adhesive layer is formed from an adhesive composition containing a photoacid generator (SP-056 (maximum absorption wavelength 250 nm in the range of 250 nm to 400 nm)) having a maximum absorption wavelength of 300 nm or less in the range of 250 nm to 400 nm Comparison Example 2has a lower change rate of the average transmittance in the wavelength range of 400 nm to 700 nm than Comparative Example 1 in which the pressure-sensitive adhesive layer is formed from a pressure-sensitive adhesive composition containing a photoacid generator (SP-606 (maximum absorption wavelength: 343 nm in the range of 250 nm to 400 nm)) that does not have a maximum absorption wavelength of 300 nm or less in the wavelength range of 250 nm to 400 nm.

[0266] From this, it can be seen that when the pressure-sensitive adhesive layer is formed from a pressure-sensitive adhesive composition containing a photoacid generator having a maximum absorption wavelength of 300 nm or less in the wavelength range of 250 nm to 400 nm, coloring by external light (exceeding 300 nm and 400 nm or less) can be suppressed (excellent external light stability).

[0267] This is because the pressure-sensitive adhesive layer is formed from a pressure-sensitive adhesive composition containing a photoacid generator (bis(4-tert-butylphenyl)iodonium p-toluenesulfonate (maximum absorption wavelength: 250 nm in the range of 250 nm to 400 nm)) having a maximum absorption wavelength of 300 nm or less in the wavelength range of 250 nm to 400 nm Comparison Example 3 and the pressure-sensitive adhesive layer is formed from a pressure-sensitive adhesive composition containing a photoacid generator (diphenyl-2,4,6-trimethylphenylsulfonium p-toluenesulfonate (maximum absorption wavelength: 257 nm in the range of 250 nm to 400 nm)) having a maximum absorption wavelength of 300 nm or less in the wavelength range of 250 nm to 400 nm Comparison Example 4 is the same.

[0268] And because of the excellent external light stability, it can be seen that when it is desired to leave the portion other than the colored portion in the pressure-sensitive adhesive layer transparent or to reduce the coloring amount compared to the colored portion, coloring of the portion other than the colored portion by external light can be suppressed.

[0269] Also, this is clear from the evaluation of external light stability.

[0270] Specifically, in the evaluation of outdoor light stability, the pressure-sensitive adhesive layer is formed from a pressure-sensitive adhesive composition containing a photoacid generator (SP-056, bis(4-tert-butylphenyl)iodonium p-toluenesulfonate, diphenyl-2,4,6-trimethylphenylsulfonium p-toluenesulfonate) having a maximum absorption wavelength of 300 nm or less in the wavelength range of 250 nm to 400 nm. Comparative Example 2, Example 2 ~In Examples 4, 7, and 8, the change rate is 13.9% or less after 2 weeks from the start of standing.

[0271] On the other hand, Comparative Example 1, in which the pressure-sensitive adhesive layer is formed from a pressure-sensitive adhesive composition containing a photoacid generator (SP-606) having no maximum absorption wavelength of 300 nm or less in the wavelength range of 250 nm to 400 nm, has a change rate of 60% after 2 weeks from the start of standing.

[0272] From this, it can be seen that when the pressure-sensitive adhesive layer is formed from a pressure-sensitive adhesive composition containing a photoacid generator having a maximum absorption wavelength of 300 nm or less in the wavelength range of 250 nm to 400 nm, it has excellent outdoor light stability.

[0273]

Table 1

[0274]

Table 2

Explanation of Reference Numerals

[0275] 1 Adhesive sheet 2 Pressure-sensitive adhesive layer 3 Active ray absorption layer 4 Adherend 6 Intermediate laminate 10 High light transmittance portion 11 Low light transmittance portion

Claims

Claim 1: A pressure-sensitive adhesive sheet comprising a pressure-sensitive adhesive layer made of a pressure-sensitive adhesive composition capable of reducing the visible light transmittance at a wavelength of 550 nm upon irradiation with actinic light. The pressure-sensitive adhesive composition contains a pressure-sensitive adhesive polymer that is a polymer of a monomer component, a compound that is colored by an acid, and a photoacid generator. The photoacid generator has a maximum absorption wavelength of 300 nm or less in the wavelength range of 250 nm to 400 nm. Furthermore, it comprises an actinic light absorption layer capable of absorbing the actinic light. The pressure-sensitive adhesive sheet is characterized in that the average light transmittance in the wavelength range of 300 nm to 400 nm in the actinic light absorption layer is 15% or less, and the average light transmittance in the wavelength range of 400 nm to 700 nm is 50% or more. Claim 2 The actinic light absorption layer has a wavelength region in the range of 300 nm to 400 nm where the average transmittance of the actinic light is 1% or less. The pressure-sensitive adhesive sheet according to claim 1, characterized in that the maximum wavelength X (nm) of the wavelength region and the maximum absorption wavelength Y (nm) of the photoacid generator satisfy the following formula (1). X - Y ≧ 100 (1). Claim 3 The pressure-sensitive adhesive sheet according to claim 1 or 2, characterized in that the actinic light absorption layer is an ultraviolet absorption layer capable of absorbing ultraviolet light. Claim 4 An adherend, and a pressure-sensitive adhesive sheet according to any one of claims 1 to 3 disposed on one surface of the adherend. An intermediate laminate characterized by comprising. Claim 5 The intermediate laminate according to claim 4, characterized in that the pressure-sensitive adhesive layer comprises a high light transmittance portion having a relatively large average light transmittance in the wavelength range of 400 to 700 nm and a low light transmittance portion having a relatively small average light transmittance in the wavelength range of 400 to 700 nm.

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